image.png

1、创建后端项目

pom文件所需要的依赖

  1. <dependencies>
  2.         <!-- SpringBoot-Web依赖-->
  3.         <dependency>
  4.             <groupId>org.springframework.boot</groupId>
  5.             <artifactId>spring-boot-starter-web</artifactId>
  6.         </dependency>
  7.         <!-- MySQL依赖-->
  8.         <dependency>
  9.             <groupId>mysql</groupId>
  10.             <artifactId>mysql-connector-java</artifactId>
  11.             <scope>runtime</scope>
  12.         </dependency>
  13.         <!-- MybatisPlus和SpringBoot整合-->
  14.         <dependency>
  15.             <groupId>com.baomidou</groupId>
  16.             <artifactId>mybatis-plus-boot-starter</artifactId>
  17.             <version>3.5.1</version>
  18.         </dependency>
  19.         <!-- 适用版本：mybatis-plus-generator代码生成器-->
  20.         <dependency>
  21.             <groupId>com.baomidou</groupId>
  22.             <artifactId>mybatis-plus-generator</artifactId>
  23.             <version>3.5.1</version>
  24.         </dependency>
  25.         <!-- Freemarker模板引擎依赖-->
  26.         <dependency>
  27.             <groupId>org.freemarker</groupId>
  28.             <artifactId>freemarker</artifactId>
  29.             <version>2.3.31</version>
  30.         </dependency>
  31.         <!-- Swagger相关依赖-->
  32.         <dependency>
  33.             <groupId>io.springfox</groupId>
  34.             <artifactId>springfox-swagger2</artifactId>
  35.             <version>2.9.2</version>
  36.         </dependency>
  37.         <dependency>
  38.             <groupId>io.springfox</groupId>
  39.             <artifactId>springfox-swagger-ui</artifactId>
  40.             <version>2.9.2</version>
  41.         </dependency>
  42.         <!-- Lombok -->
  43.         <dependency>
  44.             <groupId>org.projectlombok</groupId>
  45.             <artifactId>lombok</artifactId>
  46.             <optional>true</optional>
  47.         </dependency>
  48.         <!-- 加入log4j2的日志框架 -->
  49.         <dependency>
  50.             <groupId>log4j</groupId>
  51.             <artifactId>log4j</artifactId>
  52.             <version>1.2.17</version>
  53.         </dependency>
  54.         <!-- Redis依赖-->
  55.         <dependency>
  56.             <groupId>org.springframework.boot</groupId>
  57.             <artifactId>spring-boot-starter-data-redis</artifactId>
  58.         </dependency>
  59.         <!-- 测试依赖-->
  60.         <dependency>
  61.             <groupId>org.springframework.boot</groupId>
  62.             <artifactId>spring-boot-starter-test</artifactId>
  63.             <scope>test</scope>
  64.         </dependency>
  65.     </dependencies>

2、上传项目到码云

image.png
项目地址：https://gitee.com/yangcunle/YangCunle-Blog

3、整合MyBatisPlus

3.1配置乐观锁和分页插件

  1. @Configuration
  2. public class MyBatisPlusConfig {
  3.     /**
  4.      * 注册乐观锁插件和分页插件
  5.      * 不同版本的配置插件不一样（本次是用的是最新的版本3.5.1）
  6.      * 详情见MyBatisPlus官方文档：https://baomidou.com
  7.      * @return
  8.      */
  9.     @Bean
  10.     public MybatisPlusInterceptor mybatisPlusInterceptor() {
  11.         MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();
  12.         //添加乐观锁
  13.         mybatisPlusInterceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
  14.         //添加分页
  15.         mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
  16.         return mybatisPlusInterceptor;
  17.     }
  18. }

3.2插入修改的填充策略

  1. @Component
  2. public class MyMetaObjectHandler implements MetaObjectHandler {
  4.     /**
  5.      * 插入时的填充策略
  6.      * @param metaObject
  7.      */
  8.     @Override
  9.     public void insertFill(MetaObject metaObject) {
  10.         //setFieldValByName(String fieldName, Object fieldVal, MetaObject metaObject)
  11.         this.setFieldValByName("createTime", new Date(), metaObject);
  12.         this.setFieldValByName("updateTime", new Date(), metaObject);
  13.     }
  15.     /**
  16.      * 修改时的填充策略
  17.      * @param metaObject
  18.      */
  19.     @Override
  20.     public void updateFill(MetaObject metaObject) {
  21.         this.setFieldValByName("updateTime", new Date(), metaObject);
  23.     }
  24. }

3.3MyBatisPlus代码生成器

  1. public class MyBatisPlusGenerator {
  2.     public static void main(String[] args) {
  3.         //数据库相关配置
  4.         String url = "jdbc:mysql://119.23.106.219:3306/ycl_blog?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC";
  5.         String username = "root";
  6.         String password = "ycl1207";
  7.         String projectPath = System.getProperty("user.dir");
  8.         //表名集合
  9.         List<String> tables = new ArrayList<>();
  10.         tables.add("t_user");
  11.         FastAutoGenerator.create(url, username, password)
  12.                 //全局配置
  13.                 .globalConfig(builder -> {
  14.                     builder.author("YangCunle") // 设置作者
  15.                             .enableSwagger() // 开启 swagger 模式
  16.                             .fileOverride() // 覆盖已生成文件
  17.                             .dateType(DateType.ONLY_DATE)
  18.                             .outputDir(projectPath + "/src/main/java"); // 指定输出目录
  19.                 })
  20.                 //包配置
  21.                 .packageConfig(builder -> {
  22.                     builder.parent("com.yangcunle.blog") // 设置父包名
  23.                             //设置包的命名
  24.                             .entity("entity")
  25.                             .service("service")
  26.                             .serviceImpl("service.impl")
  27.                             .controller("controller")
  28.                             .mapper("mapper")
  29.                             .xml("mapper")
  30.                             .pathInfo(Collections.singletonMap(OutputFile.mapperXml, projectPath + "/src/main/resources/mapper/")); // 设置mapperXml生成路径
  31.                 })
  32.                 //策略配置
  33.                 .strategyConfig(builder -> {
  34.                     builder.addInclude(tables) // 设置需要生成的表名
  35.                             .addTablePrefix("t_")// 设置过滤表前缀
  36.                             // 控制器配置：controllerBuilder
  37.                             .controllerBuilder()
  38.                             .enableHyphenStyle()//开启驼峰命名转字符
  39.                             .enableRestStyle()//设置@RestController注解
  40.                             // 逻辑层配置：serviceBuilder
  41.                             .serviceBuilder()
  42.                             .formatServiceFileName("%sService")//格式化 service 接口文件名称
  43.                             .formatServiceImplFileName("%sServiceImpl")//格式化 serviceImpl 接口文件名称
  44.                             // 实体类配置：entityBuilder
  45.                             .entityBuilder()
  46.                             .enableLombok()//设置Lombok
  47.                             .enableTableFieldAnnotation()//开启生成实体时生成字段注解
  48.                             .idType(IdType.AUTO)//设置主键类型：自增
  49.                             .versionColumnName("version")//乐观锁
  50.                             .logicDeleteColumnName("deleted")//逻辑删除
  51.                             .addTableFills(new Column("create_time", FieldFill.INSERT), new Column("update_time", FieldFill.INSERT_UPDATE))//添加、修改时间自动填充
  52.                             // Mapper配置：mapperBuilder
  53.                             .mapperBuilder()
  54.                             .enableBaseResultMap()//mapper自动生成通用查询映射结果
  55.                             .enableBaseColumnList();//mapper自动生成通用列
  56.                 })
  57.                 .templateEngine(new FreemarkerTemplateEngine()) // 使用Freemarker引擎模板，默认的是Velocity引擎模板
  58.                 .execute();
  59.     }
  60. }

3.4一键生成代码

image.png

4、统一异常处理

统一异常处理包括：全局异常处理、特殊异常处理、自定义异常处理

4.1全局异常处理

  1. @RestControllerAdvice
  2. public class GlobalExceptionHandler {
  4.     //获取日志记录器对象
  5.     private final Logger logger = Logger.getLogger(GlobalExceptionHandler.class);
  8.        /**
  9.      * 处理运行时异常
  10.      * @param e
  11.      * @return
  12.      */
  13.     @ResponseBody
  14.     @ExceptionHandler(value = RuntimeException.class)
  15.     public CommonResult handler(RuntimeException e) {
  16.         logger.error("运行时异常：{}" + e.getMessage());
  17.         return CommonResult.failed("博客系统貌似出现了问题o(╥﹏╥)o，请联系管理员处理。微信：YCL357486967");
  18.     }
  19. }

4.2特殊异常处理

我们知道的一些异常可以列举出来，进行捕获，这里以除数不能为0举例
image.png
如果不处理，就会报以下错误：
image.png

  1.     /**
  2.      * 特殊异常处理 ：ArithmeticException
  3.      * @param e
  4.      * @return
  5.      */
  6.     @ResponseBody
  7.     @ExceptionHandler(value = ArithmeticException.class)
  8.     public CommonResult handler(ArithmeticException e) {
  9.         logger.error("除数不能为0异常：{}" + e.getMessage());
  10.         return CommonResult.failed(e.getMessage());
  11.     }

成功捕获：
image.png

4.3自定义异常处理

自己创建一个自定义异常类：BlogException 继承运行时异常 RuntimeException

  1. @Data
  2. public class BlogException extends RuntimeException {
  4.     private Integer code;
  5.     private String message;
  7.     public BlogException(Integer code, String message) {
  8.         super(message);
  9.         this.code = code;
  10.         this.message = message;
  11.     }
  13.     public BlogException(ResultCode ResultCode) {
  14.         super(ResultCode.getMessage());
  15.         this.code = ResultCode.getCode();
  16.         this.message = ResultCode.getMessage();
  17.     }
  18. }

在全局异常处理中加入捕获自定义异常

  1.     /**
  2.      * 自定义异常处理
  3.      * @param e
  4.      * @return
  5.      */
  6.     @ResponseBody
  7.     @ExceptionHandler(value = BlogException.class)
  8.     public CommonResult handler(BlogException e) {
  9.         logger.error("自定义异常：{}" + e.getMessage());
  10.         return CommonResult.failed(e.getMessage());
  11.     }

测试一波：
image.png
自定义异常捕获成功
image.png

5、封装统一返回结果工具类

  1. public class ResultUtil<T>  {
  3.     // 状态码
  4.     private Integer code;
  5.     // 消息
  6.     private String msg;
  7.     // 数据
  8.     private T data;
  10.     public ResultUtil(T data) {
  11.         this.data = data;
  12.     }
  15.     /**
  16.      * 成功（无返回数据）
  17.      * @return
  18.      */
  19.     public static ResultUtil success() {
  20.         ResultUtil result = new ResultUtil<>();
  21.         result.setCode(ResponseCode.SUCCEED);
  22.         result.setMsg(ResponseMsg.SUCCEED);
  23.         return result;
  24.     }
  26.     /**
  27.      * 成功（有返回数据）
  28.      * @param data
  29.      * @param <T>
  30.      * @return
  31.      */
  32.     public static <T> ResultUtil<T> success(T data) {
  33.         ResultUtil<T> result = new ResultUtil<>(data);
  34.         result.setCode(ResponseCode.SUCCEED);
  35.         result.setMsg(ResponseMsg.SUCCEED);
  36.         return result;
  37.     }
  39.     /**
  40.      * 错误
  41.      * @param code
  42.      * @param msg
  43.      * @return
  44.      */
  45.     public static ResultUtil error(Integer code, String msg) {
  46.         ResultUtil result = new ResultUtil();
  47.         result.setCode(code);
  48.         result.setMsg(msg);
  49.         return result;
  50.     }
  52. }

6、用户模块的接口开发

  1. public class UserController {
  3.     //获取日志记录器对象
  4.     private final Logger logger = Logger.getLogger(UserController.class);
  6.     @Autowired
  7.     private UserService userService;
  9.     /**
  10.      * 分页查询用户列表
  11.      * @param username
  12.      * @param pageNum
  13.      * @param pageSize
  14.      * @return
  15.      */
  16.     @GetMapping("/list")
  17.     public ResultUtil<Page<User>> list(String username,
  18.                                        @RequestParam(required = false, defaultValue = "1") Integer pageNum,
  19.                                        @RequestParam(required = false, defaultValue = "10") Integer pageSize) {
  20.         logger.info("查询用户列表开始：入参{username}:" + username);
  21.         LambdaQueryWrapper<User> query = Wrappers.<User>lambdaQuery().orderByDesc(User::getId);
  22.         if (!StringUtils.isEmpty(username)) {
  23.             query.like(User::getUsername, username);
  24.         }
  25.         Page<User> userPage = userService.page(new Page<>(pageNum, pageSize), query);
  26.         return ResultUtil.success(userPage);
  27.     }
  29.     /**
  30.      * 保存用户
  31.      * @param user
  32.      * @return
  33.      */
  34.     @PostMapping("/save")
  35.     public ResultUtil<Boolean> save(@RequestBody User user) {
  36.         logger.info("添加用户：入参{user}:" + user.toString());
  37.         boolean result = userService.save(user);
  38.         return ResultUtil.success(result);
  39.     }
  41.     /**
  42.      * 修改用户信息
  43.      * @param user
  44.      * @return
  45.      */
  46.     @PostMapping("/update")
  47.     public ResultUtil<Boolean> update(@RequestBody User user) {
  48.         logger.info("修改用户：入参{user}:" + user.toString());
  49.         boolean result = userService.updateById(user);
  50.         return ResultUtil.success(result);
  51.     }
  53.     /**
  54.      * 查看用户信息
  55.      * @param id
  56.      * @return
  57.      */
  58.     @GetMapping("/read")
  59.     public ResultUtil<User> read(Integer id) {
  60.         logger.info("查看用户信息：入参{id}:" + id);
  61.         User user = userService.getById(id);
  62.         return ResultUtil.success(user);
  63.     }
  65.     /**
  66.      * 删除用户
  67.      * @param id
  68.      * @return
  69.      */
  70.     @GetMapping("/delete")
  71.     public ResultUtil<Boolean> delete(Integer id) {
  72.         logger.info("删除用户信息：入参{id}:" + id);
  73.         boolean result = userService.removeById(id);
  74.         return ResultUtil.success(result);
  75.     }
  77. }

7、ApiPost测试接口

image.png

https://console-docs.apipost.cn/preview/e66f1e46125af959/222ee42959f879ef
文档支持在线查看
image.png
用户列表支持分页查询

  1. http://localhost:8081/user/list

返回结果

  1. {
  2.     "code": 0,
  3.     "msg": "成功",
  4.     "data": {
  5.         "records": [
  6.             {
  7.                 "id": 3,
  8.                 "username": "ycl",
  9.                 "password": "123",
  10.                 "role": 2,
  11.                 "email": "123@qq.com",
  12.                 "phone": "123",
  13.                 "age": null,
  14.                 "headImg": null,
  15.                 "createTime": "2021-08-02T08:11:47.000+00:00",
  16.                 "updateTime": "2021-08-02T08:11:47.000+00:00",
  17.                 "deleted": 0
  18.             },
  19.             {
  20.                 "id": 2,
  21.                 "username": "乐多多",
  22.                 "password": "123456",
  23.                 "role": 2,
  24.                 "email": "123456@qq.com",
  25.                 "phone": "123456",
  26.                 "age": null,
  27.                 "headImg": null,
  28.                 "createTime": "2021-08-02T08:06:14.000+00:00",
  29.                 "updateTime": "2021-08-02T08:06:14.000+00:00",
  30.                 "deleted": 0
  31.             },
  32.             {
  33.                 "id": 1,
  34.                 "username": "admin",
  35.                 "password": "admin",
  36.                 "role": 1,
  37.                 "email": "357487967@qq.com",
  38.                 "phone": "15971397103",
  39.                 "age": 25,
  40.                 "headImg": null,
  41.                 "createTime": "2021-08-02T10:33:11.000+00:00",
  42.                 "updateTime": "2021-08-02T10:33:15.000+00:00",
  43.                 "deleted": 0
  44.             }
  45.         ],
  46.         "total": 3,
  47.         "size": 10,
  48.         "current": 1,
  49.         "orders": [],
  50.         "optimizeCountSql": true,
  51.         "searchCount": true,
  52.         "countId": null,
  53.         "maxLimit": null,
  54.         "pages": 1
  55.     }
  56. }