SpringBoot项目

简介

本项目主要参考 B站 up 主三更的视频

B站最通俗易懂手把手SpringBoot+Vue项目实战-前后端分离博客项目-Java项目 | 三更草堂 | 哔哩哔哩

工程创建

IDEA > File > New > Project > Maven ArcheType

Name: JavaProject
Location: ~\Desktop\code\Java
JDK: 1.8
Catalog: Internal
Archetype: org.apache.maven.archetypes:maven-archetype-quickstart
version: 1.0
// Advanced Settings
GroupId: com.wenxiang
ArtifactId: JavaProject
version: 1.0-SNAPSHOT

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.wenxiang</groupId>
  <artifactId>JavaProject</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>pom</packaging>

  <name>JavaProject</name>
  <url>http://maven.apache.org</url>
  <modules>
    <module>PublicFramework</module>
  </modules>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <java.version>1.8</java.version>
  </properties>

  <dependencyManagement>
    <dependencies>
      <!--Spring Boot-->
      <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-dependencies</artifactId>
        <version>2.5.0</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>

      <!--fastjson-->
      <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>fastjson</artifactId>
        <version>1.2.33</version>
      </dependency>

      <!--jwt-->
      <dependency>
        <groupId>io.jsonwebtoken</groupId>
        <artifactId>jjwt</artifactId>
        <version>0.9.0</version>
      </dependency>

      <!--mybatisplus-->
      <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>3.4.3</version>
      </dependency>

      <!--阿里云oss-->
      <dependency>
        <groupId>com.aliyun.oss</groupId>
        <artifactId>aliyun-sdk-oss</artifactId>
        <version>3.10.2</version>
      </dependency>

      <!--easyexcel-->
      <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>easyexcel</artifactId>
        <version>3.0.5</version>
      </dependency>

      <!--swagger2-->
      <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger2</artifactId>
        <version>2.9.2</version>
      </dependency>

      <!--swagger-ui-->
      <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger-ui</artifactId>
        <version>2.9.2</version>
      </dependency>
    </dependencies>
  </dependencyManagement>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.1</version>
        <configuration>
          <source>${java.version}</source>
          <target>${java.version}</target>
          <encoding>${project.build.sourceEncoding}</encoding>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

多模块开发

公共模块 PublicFramework
后台管理模块 AdminFramework
前台使用模块 UserFramework

第一个子模块-公共依赖

右键项目根目录 > New > Module > Maven ArcheType

Name: PublicFramework
Location: ~\Desktop\code\Java\JavaProject
JDK: 1.8
Parent: JavaProject
Catalog: Internal
Archetype: org.apache.maven.archetypes:maven-archetype-quickstart
version: 1.1
// Advanced Settings
GroupId: com.wenxiang
ArtifactId: PublicFramework
version: 1.0-SNAPSHOT

配置 pom.xml 文件

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-security</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-redis</artifactId>
    </dependency>

    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>fastjson</artifactId>
    </dependency>

    <dependency>
        <groupId>io.jsonwebtoken</groupId>
        <artifactId>jjwt</artifactId>
    </dependency>

    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
    </dependency>

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>

    <dependency>
        <groupId>com.aliyun.oss</groupId>
        <artifactId>aliyun-sdk-oss</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-aop</artifactId>
    </dependency>

    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>easyexcel</artifactId>
    </dependency>

    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger2</artifactId>
    </dependency>

    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger-ui</artifactId>
    </dependency>
</dependencies>

手动下载 jar 包
以 springfox-swagger2 为例, 在 maven repo 仓库中找到对应的版本 io/springfox/springfox-swagger2/2.9.2, 下载 .jar, .jar.sha1, .pom, .pom.sha1 为后缀的四个文件, 将其放到 maven 本地仓库对应的目录下.

UserFramework > src > main > resource > application.yml

server:
  port: 7777
spring:
  # 数据库相关配置
  datasource:
    url: jdbc:mysql://localhost:3306/blog?characterEncoding=utf-8
    username: root
    password: "162670"
    driver-class-name: com.mysql.cj.jdbc.Driver
  # 文件上传配置
  servlet:
    multipart:
      max-file-size: 2MB
      max-request-size: 5MB
# mybatis-plus 配置
mybatis-plus:
  configuration:
    # 日志
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
  global-config:
    # 逻辑删除字段
    db-config:
      logic-delete-field: delFlag
      logic-delete-value: 1
      logic-not-delete-value: 0
      id-type: auto

第二个子模块-后台管理

右键项目根目录 > New > Module > Maven ArcheType

Name: AdminFramework
Location: ~\Desktop\code\Java\JavaProject
JDK: 1.8
Parent: JavaProject
Catalog: Internal
Archetype: org.apache.maven.archetypes:maven-archetype-quickstart
version: 1.1
// Advanced Settings
GroupId: com.wenxiang
ArtifactId: AdminFramework
version: 1.0-SNAPSHOT

配置 pom.xml 文件

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.wenxiang</groupId>
        <artifactId>JavaProject</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>AdminFramework</artifactId>
    <packaging>jar</packaging>

    <name>AdminFramework</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <!--直接依赖PublicFramework的依赖-->
        <dependency>
            <groupId>com.wenxiang</groupId>
            <artifactId>PublicFramework</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>
</project>

第三个子模块-前台用户

右键项目根目录 > New > Module > Maven ArcheType

Name: UserFramework
Location: ~\Desktop\code\Java\JavaProject
JDK: 1.8
Parent: JavaProject
Catalog: Internal
Archetype: org.apache.maven.archetypes:maven-archetype-quickstart
version: 1.1
// Advanced Settings
GroupId: com.wenxiang
ArtifactId: UserFramework
version: 1.0-SNAPSHOT

配置 pom.xml 文件

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.wenxiang</groupId>
        <artifactId>JavaProject</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>UserFramework</artifactId>
    <packaging>jar</packaging>

    <name>UserFramework</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <!--直接依赖PublicFramework的依赖-->
        <dependency>
            <groupId>com.wenxiang</groupId>
            <artifactId>PublicFramework</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>
</project>

数据库

执行数据库脚本
连接数据库
IDEA侧栏 > DataBase > New > Data Source > MySQL
填写用户名, 密码, 名字

初次使用会提示安装组件
安装 Easy Code 插件
IDEA > File > Settings > Plugins > Easycode

配置 Easy Code 模板

IDEA > File > Settings > EasyCode > Template > Group Name: MybatisPlus > entity.java.vm

修改后的模板如下

##导入宏定义
$!{define.vm}

##保存文件（宏定义）
#save("/entity", ".java")

##包路径（宏定义）
#setPackageSuffix("entity")

##自动导入包（全局变量）
$!{autoImport.vm}
import java.io.Serializable;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

##表注释（宏定义）
#tableComment("表实体类")
@SuppressWarnings("serial")
@AllArgsConstructor
@Data
@NoArgsConstructor
public class $!{tableInfo.name} {
#foreach($column in $tableInfo.fullColumn)
    #if(${column.comment})//${column.comment}#end

    private $!{tool.getClsNameByFullName($column.type)} $!{column.name};
#end
}

点击右上角的实时调试可以来查看修改后的效果

导入数据库中的表
IDEA侧栏 > DataBase > blog > schemas > 右键article > EasyCode > Generate Code

创建实体类 Mapper 和 service

在 ==PublicFramework== > ··· > com.wenxinag 下创建 domain 包, 将整个 entity 移入 domain 下

同时在 com.wenxiang 下创建 Mapper 包和 service 包

在 Mapper 下新建 Java Class 命名 ArticleMapper

package com.wenxiang.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.wenxiang.domain.entity.Article;

public interface ArticleMapper extends BaseMapper<Article> {
    
}

在 service 下新建 Java Class 命名 ArticleService

package com.wenxiang.sevice;

import com.baomidou.mybatisplus.extension.service.IService;
import com.wenxiang.domain.entity.Article;

public interface ArticleService extends IService<Article> {
    
}

在 service 下新建 Java Class 命名 impl.ArticleServiceImpl

package com.wenxiang.sevice.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.wenxiang.domain.entity.Article;
import com.wenxiang.mapper.ArticleMapper;
import com.wenxiang.sevice.ArticleService;
import org.springframework.stereotype.Service;

@Service
public class ArticleServiceImpl extends ServiceImpl<ArticleMapper, Article> implements ArticleService {
    
}

创建 controller

在 ==UserFramework== > ··· > com.wenxinag 下创建 controller 包
在 controller 包下新建 Java Class, 命名 ArticleController

package com.wenxiang.controller;

import com.wenxiang.domain.entity.Article;
import com.wenxiang.sevice.ArticleService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
@RequestMapping("/article")
public class ArticleController {

    @Autowired
    private ArticleService articleService;

    @GetMapping("/list")
    public List<Article> test(){
        return articleService.list();
    }
}

此时切到 UserFramework 下的 BlogApplication, 点击 Run, 报错如下

1	Error creating bean with name 'articleController': Unsatisfied dependency expressed through field 'articleService'; ...

这是由于 UserFramework 对 PublicFramework 模块的依赖还停留在老版本, 于是 PublicFramework 下新建的新建的类就没有出现在 UserFramework 的依赖中
处理方法是在 Maven 中, 选择父工程, JavaProject > Lifecycle > 双击install, 重新打包依赖

关于 Cannot resolve symbol junit 报错
是由于此前在 pom.xml 中注释掉了关于 junit 的依赖

<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>3.8.1</version>
    <scope>test</scope>
</dependency>

第二次运行 BlogApplication.java 报错, 此时需要添加

...
@MapperScan("com.wenxiang.mapper") //添加映射
public class BlogApplication {
    ...
}

此时运行成功.
在浏览器地址栏中输入 localhost:7777/article/list, 并没有出现 article, 而是加载出登录页面, 这是由于项目依赖了 spring-boot-starter-security 造成的.
当前为了方便测试, 暂时将 PublicFramework 下 pom.xml 中关于 spring-boot-starter-security 的依赖注释掉.

<!--        <dependency>-->
<!--            <groupId>org.springframework.boot</groupId>-->
<!--            <artifactId>spring-boot-starter-security</artifactId>-->
<!--        </dependency>-->

注释之后需要先更新 Maven, 然后由于修改了 PublicFramework 所以需要再次 Maven > JavaProject (root) > Lifecycle > 双击install, 重新打包

打包完成后重启项目, 浏览器访问 localhost:7777/article/list, 再次报错
报错状态为 500, Console 中给出的报错信息为 Access denied for user 'root'@'localhost' (using password: YES), 排查为 UserFramework > src > main > resource > application.yml 中关于数据库的配置有问题, 修改 password 字段

server:
  port: 7777
spring:
  # 数据库相关配置
  datasource:
    url: jdbc:mysql://localhost:3306/blog?characterEncoding=utf-8
    username: root
    password: "162670" #记得加上双引号
    driver-class-name: com.mysql.cj.jdbc.Driver

重新运行, 刷新浏览器页面, 正常显示出 article 中的内容.

课程中出现的一个报错: Table 'sg_blog.article' doesn't exist
这是由于课程中示例的数据库 sg_blog 中的表单名称为 sg_article, 但是对应的实体类名称为 Article, 再没有额外指明的情况下, Java 默认认为数据的名称和实体类的名称一致, 所以去 sg_blog 数据库下查询 article 表单而没有找到, 所以返回上述信息.
解决办法: 在 PublicFramework/src/main/java/com/wenxiang/domain/entity/Article.java 实体类中添加一个注解, 让其和数据库表单的名称对应起来, 如下

...
@TableName("数据库对应的表单名称") //添加 TableName 注解, 将数据库表单的名称和实体类建立映射
public class Article {

    @TableId //添加 TableId 注解
    private Long id;
    ...
}

而我在实际操作的时候, 数据库表单名称 article (没有 sg_ 前缀)和实体类名称 Article 是一致的, 所以没有报这个错误.

热门文章列表

Note: 在项目目录上栏右侧的 Options > Tree Appearance > 取消勾选 Compact Middle Packges 可以展开连在一起的 Package

准备工作

右键 PublicFramework/src/main/java/com/wenxiang/domain 目录, 粘贴下面的代码, IDEA 将直接创建一个 Java Class 类

package com.wenxiang.domain;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.wenxiang.enums.AppHttpCodeEnum;

import java.io.Serializable;

@JsonInclude(JsonInclude.Include.NON_NULL)
public class ResponseResult<T> implements Serializable {
    private Integer code;
    private String msg;
    private T data;

    public ResponseResult() {
        this.code = AppHttpCodeEnum.SUCCESS.getCode();
        this.msg = AppHttpCodeEnum.SUCCESS.getMsg();
    }

    public ResponseResult(Integer code, T data) {
        this.code = code;
        this.data = data;
    }

    public ResponseResult(Integer code, String msg, T data) {
        this.code = code;
        this.msg = msg;
        this.data = data;
    }

    public ResponseResult(Integer code, String msg) {
        this.code = code;
        this.msg = msg;
    }

    public static ResponseResult errorResult(int code, String msg) {
        ResponseResult result = new ResponseResult();
        return result.error(code, msg);
    }
    public static ResponseResult okResult() {
        ResponseResult result = new ResponseResult();
        return result;
    }
    public static ResponseResult okResult(int code, String msg) {
        ResponseResult result = new ResponseResult();
        return result.ok(code, null, msg);
    }

    public static ResponseResult okResult(Object data) {
        ResponseResult result = setAppHttpCodeEnum(AppHttpCodeEnum.SUCCESS, AppHttpCodeEnum.SUCCESS.getMsg());
        if(data!=null) {
            result.setData(data);
        }
        return result;
    }

    public static ResponseResult errorResult(AppHttpCodeEnum enums){
        return setAppHttpCodeEnum(enums,enums.getMsg());
    }

    public static ResponseResult errorResult(AppHttpCodeEnum enums, String msg){
        return setAppHttpCodeEnum(enums,msg);
    }

    public static ResponseResult setAppHttpCodeEnum(AppHttpCodeEnum enums){
        return okResult(enums.getCode(),enums.getMsg());
    }

    private static ResponseResult setAppHttpCodeEnum(AppHttpCodeEnum enums, String msg){
        return okResult(enums.getCode(),msg);
    }

    public ResponseResult<?> error(Integer code, String msg) {
        this.code = code;
        this.msg = msg;
        return this;
    }

    public ResponseResult<?> ok(Integer code, T data) {
        this.code = code;
        this.data = data;
        return this;
    }

    public ResponseResult<?> ok(Integer code, T data, String msg) {
        this.code = code;
        this.data = data;
        this.msg = msg;
        return this;
    }

    public ResponseResult<?> ok(T data) {
        this.data = data;
        return this;
    }

    public Integer getCode() {
        return code;
    }

    public void setCode(Integer code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public T getData() {
        return data;
    }

    public void setData(T data) {
        this.data = data;
    }
    
}

在 PublicFramework/src/main/java/com/wenxiang 目录下创建 Package 命名为 enums, 右键 enums 粘贴下面的代码

package com.wenxiang.enums;

public enum AppHttpCodeEnum {
    // 成功
    SUCCESS(200,"操作成功"),
    // 登录
    NEED_LOGIN(401,"需要登录后操作"),
    NO_OPERATOR_AUTH(403,"无权限操作"),
    SYSTEM_ERROR(500,"出现错误"),
    USERNAME_EXIST(501,"用户名已存在"),
    PHONENUMBER_EXIST(502,"手机号已存在"), EMAIL_EXIST(503, "邮箱已存在"),
    REQUIRE_USERNAME(504, "必需填写用户名"),
    LOGIN_ERROR(505,"用户名或密码错误");
    int code;
    String msg;

    AppHttpCodeEnum(int code, String errorMessage){
        this.code = code;
        this.msg = errorMessage;
    }

    public int getCode() {
        return code;
    }

    public String getMsg() {
        return msg;
    }
}

代码实现

UserFramework/src/main/java/com/wenxiang/controller/ArticleController.java

package com.wenxiang.controller;

import com.wenxiang.domain.ResponseResult;
import com.wenxiang.domain.entity.Article;
import com.wenxiang.sevice.ArticleService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
@RequestMapping("/article")
public class ArticleController {

    @Autowired
    private ArticleService articleService;

//    @GetMapping("/list")
//    public List<Article> test(){
//        return articleService.list();
//    }

    @GetMapping("/hotArticleList")
    public ResponseResult hotArticleList(){

        ResponseResult result = articleService.hotArticleList();
        return result;
    }
}

PublicFramework/src/main/java/com/wenxiang/sevice/ArticleService.java

package com.wenxiang.sevice;

import com.baomidou.mybatisplus.extension.service.IService;
import com.wenxiang.domain.ResponseResult;
import com.wenxiang.domain.entity.Article;

public interface ArticleService extends IService<Article> {

    ResponseResult hotArticleList();
}

PublicFramework/com/wenxiang/sevice/impl/ArticleServiceImpl.java

package com.wenxiang.sevice.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.wenxiang.domain.ResponseResult;
import com.wenxiang.domain.entity.Article;
import com.wenxiang.mapper.ArticleMapper;
import com.wenxiang.sevice.ArticleService;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class ArticleServiceImpl extends ServiceImpl<ArticleMapper, Article> implements ArticleService {

    @Override
    public ResponseResult hotArticleList() {
        //查询热门文章, 封装成 ResponseResult 并返回
        LambdaQueryWrapper<Article> queryWrapper = new LambdaQueryWrapper<>();
        //必须是正式文章
        queryWrapper.eq(Article::getStatus, 0);
        //按照浏览量进行排序
        queryWrapper.orderByDesc(Article::getViewCount);
        //最多之查询10条
        Page<Article> page = new Page(1, 10);
        page(page, queryWrapper);

        List<Article> articles = page.getRecords();
        return ResponseResult.okResult(articles);
    }
}

Postman 测试
Run BlogApplication.java, 正常运行
在 Postman Desktop 中使用 GET 访问 http://localhost:7777/article/hotArticleList

Note: 使用 Postman Desktop 版本进行测试, 使用网页版不能正确得到 Response, 给出下面提示:
Could not send request
Cloud Agent Error: Can not send requests to localhost. Select a different agent. | Use Postman's Desktop Agent

前端工程联调

安装依赖和启动

切到前端工程 blog-vue 目录下, 调出 cmd

# install dependencies
npm install

# serve with hot reload at localhost:8080 
npm run dev

直接只用 npm install 报错, 请按照下面步骤使用 cnpm 安装依赖

清除缓存
1
npm cache clean --force
删除项目中的 node_modules 文件夹

安装 cnpm

1	npm install -g cnpm --registry=https://registry.npm.taobao.org

用 cnpm 安装依赖
1
cnpm install

测试联调

解决跨域访问问题

PublicFramework/src/main/java/com/wenxiang/ 下新建 config 包, 右键粘贴下面代码

package com.wenxiang.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addCorsMappings(CorsRegistry registry) {
      // 设置允许跨域的路径
        registry.addMapping("/**")
                // 设置允许跨域请求的域名
                .allowedOriginPatterns("*")
                // 是否允许cookie
                .allowCredentials(true)
                // 设置允许的请求方式
                .allowedMethods("GET", "POST", "DELETE", "PUT")
                // 设置允许的header属性
                .allowedHeaders("*")
                // 跨域允许时间
                .maxAge(3600);
    }
}

Maven 下重新 install 整个项目, 重启项目. 此时刷新前端页面, 可以看到 “热门文章” 栏.
可以 F12 (或者鼠标右键>检查) 调出开发者工具, 切换到 Network, 点击页面地址栏左边的刷新, 筛选选择 Fetch/XHR, 可以看到 hotArticleList, 点击 Preview 可以看到返回的信息.

VO 优化

VO 即 View Object

在 PublicFramework/src/main/java/com/wenxiang/domain 目录下新建 Package 命名为 vo, 在 vo 下新建 Java Class 命名为 HotArticleVo

PublicFramework/src/main/java/com/wenxiang/domain/vo/HotArticleVo.java

package com.wenxiang.domain.vo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class HotArticleVo {
    private Long id;
    //标题
    private String title;
    //访问量
    private String viewCount;
}

PublicFramework/src/main/java/com/wenxiang/sevice/impl/ArticleServiceImpl.java

package com.wenxiang.sevice.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.fasterxml.jackson.databind.util.BeanUtil;
import com.wenxiang.domain.ResponseResult;
import com.wenxiang.domain.entity.Article;
import com.wenxiang.domain.vo.HotArticleVo;
import com.wenxiang.mapper.ArticleMapper;
import com.wenxiang.sevice.ArticleService;
import org.springframework.beans.BeanUtils;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

@Service
public class ArticleServiceImpl extends ServiceImpl<ArticleMapper, Article> implements ArticleService {

    @Override
    public ResponseResult hotArticleList() {
        //查询热门文章, 封装成 ResponseResult 并返回
        LambdaQueryWrapper<Article> queryWrapper = new LambdaQueryWrapper<>();
        //必须是正式文章
        queryWrapper.eq(Article::getStatus, 0);
        //按照浏览量进行排序
        queryWrapper.orderByDesc(Article::getViewCount);
        //最多之查询10条
        Page<Article> page = new Page(1, 10);
        page(page, queryWrapper);

        List<Article> articles = page.getRecords();

        // Bean 拷贝
        List<HotArticleVo> articleVos = new ArrayList<>();
        for (Article article : articles) {
            HotArticleVo vo = new HotArticleVo();
            BeanUtils.copyProperties(article, vo);
            articleVos.add(vo);
        }

        return ResponseResult.okResult(articleVos);
    }
}

字面量处理

PublicFramework/src/main/java/com/wenxiang/constants/SystemConstants.java

public class SystemConstants
{
    /**
     *  文章是草稿
     */
    public static final int ARTICLE_STATUS_DRAFT = 1;
    /**
     *  文章是正常分布状态
     */
    public static final int ARTICLE_STATUS_NORMAL = 0;
    
}

将 PublicFramework/src/main/java/com/wenxiang/sevice/impl/ArticleServiceImpl.java 中的 0 修改为 SystemConstants.ARTICLE_STATUS_NORMAL

...
    @Override
    public ResponseResult hotArticleList() {
        ...
        queryWrapper.eq(Article::getStatus, SystemConstants.ARTICLE_STATUS_NORMAL);
        ...
    }
...

Bean 拷贝工具类封装

PublicFramework\src\main\java\com\wenxiang\utils\BeanCopyUtils.java

package com.wenxiang.utils;

import com.wenxiang.constants.SystemConstants;
import com.wenxiang.domain.entity.Article;
import com.wenxiang.domain.vo.HotArticleVo;
import org.springframework.beans.BeanUtils;

import java.sql.SQLOutput;
import java.util.List;
import java.util.stream.Collectors;

public class BeanCopyUtils {

    private BeanCopyUtils(){

    }

    public static <V> V copyBean(Object source, Class<V> clazz) {
        // 创建目标对象
        V result = null;
        try {
            result = clazz.newInstance();
            // 实现属性 Copy
            BeanUtils.copyProperties(source, result);

        } catch (Exception e) {
            e.printStackTrace();
        }

        // 返回结果
        return result;
    }

    public static <O, V> List<V> copyBeanList(List<O> list, Class<V> clazz){
        return list.stream()
                .map(o -> copyBean(o, clazz))
                .collect(Collectors.toList());
    }

    public static void main(String[] args){
        Article article = new Article();
        article.setId(1L);
        article.setTitle("ss");

        HotArticleVo hotArticleVo = copyBean(article, HotArticleVo.class);
        System.out.println(hotArticleVo);

    }
}

PublicFramework\src\main\java\com\wenxiang\sevice\impl\ArticleServiceImpl.java

package com.wenxiang.sevice.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.fasterxml.jackson.databind.util.BeanUtil;
import com.wenxiang.constants.SystemConstants;
import com.wenxiang.domain.ResponseResult;
import com.wenxiang.domain.entity.Article;
import com.wenxiang.domain.vo.HotArticleVo;
import com.wenxiang.mapper.ArticleMapper;
import com.wenxiang.sevice.ArticleService;
import com.wenxiang.utils.BeanCopyUtils;
import org.springframework.beans.BeanUtils;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

@Service
public class ArticleServiceImpl extends ServiceImpl<ArticleMapper, Article> implements ArticleService {

    @Override
    public ResponseResult hotArticleList() {
        //查询热门文章, 封装成 ResponseResult 并返回
        LambdaQueryWrapper<Article> queryWrapper = new LambdaQueryWrapper<>();
        //必须是正式文章
        queryWrapper.eq(Article::getStatus, SystemConstants.ARTICLE_STATUS_NORMAL);
        //按照浏览量进行排序
        queryWrapper.orderByDesc(Article::getViewCount);
        //最多之查询10条
        Page<Article> page = new Page(1, 10);
        page(page, queryWrapper);

        List<Article> articles = page.getRecords();

//        // Bean 拷贝
//        List<HotArticleVo> articleVos = new ArrayList<>();
//        for (Article article : articles) {
//            HotArticleVo vo = new HotArticleVo();
//            BeanUtils.copyProperties(article, vo);
//            articleVos.add(vo);
//        }

        List<HotArticleVo> vs = BeanCopyUtils.copyBeanList(articles, HotArticleVo.class);

        return ResponseResult.okResult(vs);
    }
}

分类列表查询

EasyCode 代码模板

IDEA > File > Settings > EasyCode > Template > Group Name: MybatisPlus > entity.java.vm

##导入宏定义
$!{define.vm}

##保存文件（宏定义）
#save("/entity", ".java")

##包路径（宏定义）
#setPackageSuffix("entity")

##自动导入包（全局变量）
$!{autoImport.vm}

import java.io.Serializable;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
##表注释（宏定义）
#tableComment("表实体类")
@SuppressWarnings("serial")
@Data
@AllArgsConstructor
@NoArgsConstructor
@TableName("$!{tableInfo.obj.name}")
public class $!{tableInfo.name}  {
#foreach($column in $tableInfo.pkColumn)
    #if(${column.comment})//${column.comment}#end
@TableId
    private $!{tool.getClsNameByFullName($column.type)} $!{column.name};
#end

#foreach($column in $tableInfo.otherColumn)
    #if(${column.comment})//${column.comment}#end

    private $!{tool.getClsNameByFullName($column.type)} $!{column.name};
#end
}

IDEA > File > Settings > EasyCode > Template > Group Name: MybatisPlus > dao.java.vm

##导入宏定义
$!{define.vm}

##设置表后缀（宏定义）
#setTableSuffix("Mapper")

##保存文件（宏定义）
#save("/mapper", "Mapper.java")

##包路径（宏定义）
#setPackageSuffix("mapper")

import com.baomidou.mybatisplus.core.mapper.BaseMapper;


##表注释（宏定义）
#tableComment("表数据库访问层")
public interface $!{tableName} extends BaseMapper<$!tableInfo.name> {

}

IDEA > File > Settings > EasyCode > Template > Group Name: MybatisPlus > service.java.vm

##导入宏定义
$!{define.vm}

##设置表后缀（宏定义）
#setTableSuffix("Service")

##保存文件（宏定义）
#save("/service", "Service.java")

##包路径（宏定义）
#setPackageSuffix("service")

import com.baomidou.mybatisplus.extension.service.IService;


##表注释（宏定义）
#tableComment("表服务接口")
public interface $!{tableName} extends IService<$!tableInfo.name> {

}

IDEA > File > Settings > EasyCode > Template > Group Name: MybatisPlus > serviceImpl.java.vm

##导入宏定义
$!{define.vm}

##设置表后缀（宏定义）
#setTableSuffix("ServiceImpl")

##保存文件（宏定义）
#save("/service/impl", "ServiceImpl.java")

##包路径（宏定义）
#setPackageSuffix("service.impl")

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.stereotype.Service;

##表注释（宏定义）
#tableComment("表服务实现类")
@Service("$!tool.firstLowerCase($tableInfo.name)Service")
public class $!{tableName} extends ServiceImpl<$!{tableInfo.name}Mapper, $!{tableInfo.name}> implements $!{tableInfo.name}Service {

}

IDEA侧栏 > DataBase > blog > schemas > 右键category > EasyCode > Generate Code

Easy Code

这个是直接在 java 目录下创建的, 要将 mapper, entity, service 和 serviceImpl 分别移入到各自的目录下

分类列表代码实现

UserFramework\src\main\java\com\wenxiang\controller\CategoryController.java

package com.wenxiang.controller;

import com.wenxiang.domain.ResponseResult;
import com.wenxiang.sevice.CategoryService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/category")
public class CategoryController {

    @Autowired
    private CategoryService categoryService;

    @GetMapping("/getCategoryList")
    public ResponseResult getCategoryList(){
        return categoryService.getCategoryList();
    }
}

PublicFramework\src\main\java\com\wenxiang\sevice\CategoryService.java

package com.wenxiang.sevice;

import com.baomidou.mybatisplus.extension.service.IService;
import com.wenxiang.domain.ResponseResult;
import com.wenxiang.domain.entity.Category;


/**
 * 分类表(Category)表服务接口
 *
 * @author makejava
 * @since 2023-05-28 21:22:01
 */
public interface CategoryService extends IService<Category> {

    ResponseResult getCategoryList();
}

PublicFramework\src\main\java\com\wenxiang\sevice\impl\CategoryServiceImpl.java

package com.wenxiang.sevice.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.wenxiang.constants.SystemConstants;
import com.wenxiang.domain.ResponseResult;
import com.wenxiang.domain.entity.Article;
import com.wenxiang.domain.entity.Category;
import com.wenxiang.domain.vo.CategoryVo;
import com.wenxiang.mapper.CategoryMapper;
import com.wenxiang.sevice.ArticleService;
import com.wenxiang.sevice.CategoryService;
import com.wenxiang.utils.BeanCopyUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Set;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.Stream;

/**
 * 分类表(Category)表服务实现类
 *
 * @author makejava
 * @since 2023-05-28 21:22:02
 */
@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryMapper, Category> implements CategoryService {

    @Autowired
    private ArticleService articleService;

    @Override
    public ResponseResult getCategoryList() {
        //查询文章表, 状态为已发布的文章
        LambdaQueryWrapper<Article> articleWrapper = new LambdaQueryWrapper<>();
        articleWrapper.eq(Article::getStatus, SystemConstants.ARTICLE_STATUS_NORMAL);
        List<Article> articleList = articleService.list(articleWrapper);

        //获取文章的分类id, 并且去重
        Set<Long> categoryIds = articleList.stream()
                .map(article -> article.getCategoryId())
                .collect(Collectors.toSet());

        //查询分类表
        List<Category> categories = listByIds(categoryIds);

        categories = categories.stream()
                .filter(category -> SystemConstants.STATUS_NORMAL.equals(category.getStatus()))
                .collect(Collectors.toList());

        //封装vo
        List<CategoryVo> categoryVos = BeanCopyUtils.copyBeanList(categories, CategoryVo.class);

        return ResponseResult.okResult(categoryVos);
    }
}

PublicFramework\src\main\java\com\wenxiang\domain\vo\CategoryVo.java

package com.wenxiang.domain.vo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class CategoryVo {

    private Long id;
    private String name;

}

PublicFramework\src\main\java\com\wenxiang\constants\SystemConstants.java 中添加常量

1	public static final String STATUS_NORMAL = "0";

Postman 测试

http://localhost:7777/category/getCategoryList

查询文章列表

查询文章列表代码实现

在 UserFramework\src\main\java\com\wenxiang\controller\ArticleController.java 中添加 articleList 方法

...
@RestController
@RequestMapping("/article")
public class ArticleController {

    ...

    @GetMapping("/articleList")
    public ResponseResult articleList(Integer pageNum, Integer pageSize, Long categoryId){
        return articleService.articleList(pageNum, pageSize, categoryId);
    }
}

articleList 的具体实现是在 articleService 中实现的

Note: 光标放到标红的 articleList 上 Alt+Enter,
Create method 'articleList' in 'ArticleService' + Enter
可以快速在 ArticleService 中创建该方法

PublicFramework\src\main\java\com\wenxiang\sevice\ArticleService.java

...
public interface ArticleService extends IService<Article> {

    ...

    ResponseResult articleList(Integer pageNum, Integer pageSize, Long categoryId);
}

Note: Alt+Ctrl+鼠标左键点击 ArticleService 可以快速跳转到实现类 ArticleServiceImpl

PublicFramework\src\main\java\com\wenxiang\sevice\impl\ArticleServiceImpl.java

Note: 光标放到标红色波浪线的地方 Alt+Enter > Implement methods + Enter > articleList(…) + Enter 可以快速在 ArticleServiceImpl 中创建 articleList() 方法

...
@Service
public class ArticleServiceImpl extends ServiceImpl<ArticleMapper, Article> implements ArticleService {

    ...

    @Override
    public ResponseResult articleList(Integer pageNum, Integer pageSize, Long categoryId) {
        //查询条件
        LambdaQueryWrapper<Article> lambdaQueryWrapper = new LambdaQueryWrapper<>();

        //如果有 categoryId 就要 查询时和传入的相同
        lambdaQueryWrapper.eq(Objects.nonNull(categoryId)&&categoryId>0, Article::getCategoryId, categoryId);

        //状态是正式发布的
        lambdaQueryWrapper.eq(Article::getStatus, SystemConstants.ARTICLE_STATUS_NORMAL);

        //对 isTop 进行降序排序
        lambdaQueryWrapper.orderByDesc(Article::getIsTop);


        //分页查询
        Page<Article> page = new Page<>(pageNum, pageSize);
        page(page, lambdaQueryWrapper);

        //封装查询结果
        List<ArticleListVo> articleListVos = BeanCopyUtils.copyBeanList(page.getRecords(), ArticleListVo.class);

        PageVo pageVo = new PageVo(articleListVos, page.getTotal());
        return ResponseResult.okResult(pageVo);
    }
}

PublicFramework\src\main\java\com\wenxiang\domain\vo\ArticleListVo.java

package com.wenxiang.domain.vo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.Date;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class ArticleListVo {

    private Long id;
    //标题
    private String title;
    //文章内容
    private String content;
    //文章摘要
    private String summary;
    //所属分类名
    private Long categoryName;
    //缩略图
    private String thumbnail;
    //访问量
    private Long viewCount;
    private Date createTime;
}

PublicFramework\src\main\java\com\wenxiang\domain\vo\PageVo.java

package com.wenxiang.domain.vo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.List;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class PageVo {
    private List rows;
    private Long total;
}

Postman 测试

http://localhost:7777/article/articleList

报错, 返回状态码 500

{
    "timestamp": "2023-05-29T03:39:38.178+00:00",
    "status": 500,
    "error": "Internal Server Error",
    "path": "/article/articleList"
}

传入参数

MybatisPlus 分页支持配置
PublicFramework\src\main\java\com\wenxiang\config\MbatisPlusConfig.java

@Configuration
public class MbatisPlusConfig {

    /**
     * 3.4.0之后版本
     * @return
     */
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor(){
        MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();
        mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor());
        return mybatisPlusInterceptor;
    }
}

配置完成后重新 install, Postman 中再次检测, 分页正常

分页正常

分类名称问题解决-普通循环方式

添加 categoryName 字段, 并且要加上注释
PublicFramework\src\main\java\com\wenxiang\domain\entity\Article.java

...
public class Article {
    ...
    @TableField(exist = false) //注释
    private String categoryName;
    ...
}

主体代码
PublicFramework\src\main\java\com\wenxiang\sevice\impl\ArticleServiceImpl.java

...
@Service
public class ArticleServiceImpl extends ServiceImpl<ArticleMapper, Article> implements ArticleService {
    ...
    @Override
    public ResponseResult articleList(...) {
        ...
        //分页查询
        ...
        //查询categoryName
        List<Article> articles = page.getRecords();
        //articleId去查询articleName进行设置
        for (Article article : articles) {
            Category category = categoryService.getById(article.getCategoryId());
            article.setCategoryName(category.getName());
        }
        //封装查询结果
        ...
    }
}

测试没有正常显示 categoryName 字段, 修改 categoryName 的属性为 String 类型
PublicFramework\src\main\java\com\wenxiang\domain\vo\ArticleListVo.java
1
2
3
4
5
6
7
8
...
public class ArticleListVo {
...
//所属分类名
// private Long categoryName;
private String categoryName;
...
}
再次测试, 成功

http://localhost:7777/article/articleList?pageNum=1&pageSize=10&categoryId=1

分类名称问题解决-Stream流

PublicFramework\src\main\java\com\wenxiang\sevice\impl\ArticleServiceImpl.java

...
@Service
public class ArticleServiceImpl extends ServiceImpl<ArticleMapper, Article> implements ArticleService {

    ...

    @Override
    public ResponseResult articleList(Integer pageNum, Integer pageSize, Long categoryId) {
        ...
        List<Article> articles = page.getRecords();
        //查询categoryName
        articles.stream()
                .map(article -> article.setCategoryName(categoryService.getById(article.getCategoryId()).getName()))
                .collect(Collectors.toList());

        //封装查询结果
        ...
    }
}