ResponseEntity为单独接口实现灵活返回值控制

• 2019 年 12 月 20 日
• 筆記

Restful API的Web后台服务，一般都提供了统一的接口规范。但是有时候又需要提供回调地址给外部服务，比如微信支付。那么这个回调接口的返回值需要满足微信支付回调的返回值协议（这个协议跟项目的Web后台服务不一致）。 利用ResponseEntity可以单独为某个接口实现返回值的完全控制，也不用修改项目的整体协议规范。

实现

• 项目的统一返回值协议WebResult

/**   * @author timxia   * @since 2019/8/13   */  @Getter  @Setter  @ToString  @NoArgsConstructor  public class WebResult<T> {      private static final int SUCCESS_CODE = 200;      private static final int SERVER_ERROR_CODE = 500;        private static final String SUCCESS_MSG = "操作成功";      private static final String ERROR_SERVER = "服务器繁忙，请稍后再试";        public static final WebResult<Void> SUCCESS_RESULT = new WebResult<>();      public static final WebResult<Void> SERVER_ERROR_RESULT = new WebResult<>(SERVER_ERROR_CODE, ERROR_SERVER);        /**       * 错误码.       */      private int code = SUCCESS_CODE;        /**       * 错误信息.       */      private String msg = SUCCESS_MSG;        /**       * 结果内容.       */      private T data;        public WebResult(int code, String msg) {          this.code = code;          this.msg = msg;      }        public WebResult(T data) {          this.data = data;      }  }

• 返回不同的HttpStatus

@RequestMapping("home")  @RestController  @SpringBootApplication  public class BootEntityApplication {        public static void main(String[] args) {          SpringApplication.run(BootEntityApplication.class, args);      }        @GetMapping("ping")      public WebResult<Void> ping() {          return WebResult.SUCCESS_RESULT;      }        /**       * 根据不同的异常情况，配置不同的HttpStatus       */      @GetMapping("exception")      public ResponseEntity<WebResult> exception(int ex) {          try {              doWork(ex);              return ResponseEntity.ok(WebResult.SUCCESS_RESULT);          } catch (IllegalArgumentException e) {              //不同的异常设置不同的HttpStatus              return ResponseEntity.status(HttpStatus.BAD_REQUEST)                      .body(new WebResult<>(400, e.getMessage()));          } catch (RuntimeException e) {              return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR)                      .body(WebResult.SERVER_ERROR_RESULT);          }      }        private void doWork(int ex) {          switch (ex) {              case 0:                  return;              case 1:                  throw new IllegalArgumentException("bad request");              default:                  throw new RuntimeException("服务器繁忙");          }      }  }

测试

# 没有异常HttpStatus=200  $ curl -i -X GET 'http://localhost:8080/home/exception?ex=0'    HTTP/1.1 200  Content-Type: application/json  Transfer-Encoding: chunked  Date: Tue, 17 Dec 2019 13:29:55 GMT    {"code":200,"msg":"操作成功","data":null,"success":true}    #参数异常HttpStatus=400  $ curl -i -X GET 'http://localhost:8080/home/exception?ex=1'    HTTP/1.1 400  Content-Type: application/json  Transfer-Encoding: chunked  Date: Tue, 17 Dec 2019 13:29:19 GMT  Connection: close    {"code":400,"msg":"bad request","data":null,"success":false}    #服务器异常HttpStatus=500  $ curl -i -X GET 'http://localhost:8080/home/exception?ex=2'    HTTP/1.1 500  Content-Type: application/json  Transfer-Encoding: chunked  Date: Tue, 17 Dec 2019 13:30:05 GMT  Connection: close    {"code":500,"msg":"服务器繁忙，请稍后再试","data":null,"success":false}

优点

• 使用ResponseEntity可以针对单个接口实现灵活的返回值控制，包括HttpStatus
• 如果在所有接口实现对某一个异常都设置统一的HttpStatus，可以使用ExceptionHandler
• 使用HttpServletResponse也可以实现非常灵活的返回值控制，但是太底层了，不够面向对象，不建议使用