使用 @ControllerAdvice 和 实现ResponseBodyAdvice接口， 拦截Controller方法默认返回参数，统一处理返回值/响应体

1、Controller代码
以下是Controller方法源码：

@RestController
@RequestMapping("/manage/user")
public class TestController {private Logger logger = LoggerFactory.getLogger(TestController.class);/*** 通过会员id获取会员信息及详情** @param id 会员id* @return app msg*/@GetMapping("/edit/{id}")public AppMessage edit(@PathVariable Integer id) {if (null == id) {return AppMessage.error(-3, "会员ID不能为空");}// 查询会员对象User user = userService.queryById(id);if (user == null) {return AppMessage.error(-3, "根据会员ID未查询到对应会员");}return AppMessage.success(user);}}

2、拦截处理器
下面已经封装好了一个拦截处理类以供参考：

package com.yclimb.test;import org.springframework.core.MethodParameter;
import org.springframework.http.MediaType;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;/*** 拦截Controller方法默认返回参数，统一处理返回值/响应体*/
@ControllerAdvice
public class TestResponseBodyAdvice implements ResponseBodyAdvice {@Overridepublic Object beforeBodyWrite(Object o, MethodParameter methodParameter, MediaType mediaType, Class aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {System.out.println("TestResponseBodyAdvice==>beforeBodyWrite:" + o.toString() + ","+ methodParameter);return o;}@Overridepublic boolean supports(MethodParameter methodParameter, Class aClass) {return true;}
}

ResponseBodyAdvice

方法讲解

• supports对你需要进行拦截的response进行判断筛选，返回true则进行拦截反之放行，
• beforeBodyWrite对supports进行拦截的response进行处理，封装你需要的类型参数，加密等等。

个人理解：

ResponseBodyAdvice 接口是在 Controller 执行 return 之后，在 response 返回给客户端之前，执行的对 response 的一些处理，可以实现对 response 数据的一些统一封装或者加密等操作。

该接口一共有两个方法：

（1）supports —— 判断是否要执行beforeBodyWrite方法，true为执行，false不执行 —— 通过supports方法，我们可以选择哪些类或哪些方法要对response进行处理，其余的则不处理。

（2）beforeBodyWrite —— 对 response 处理的具体执行方法。

package com.abc.demo;import com.github.pagehelper.Page;
import com.abc.pojo.bean.ResponseResult;
import org.springframework.core.MethodParameter;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;@ControllerAdvice
public class ControllerAdviceHandler implements ResponseBodyAdvice<Object> {@ResponseBody@ExceptionHandler(value = Throwable.class)public ResponseResult catchAllError(HttpServletRequest request, HttpServletResponse response, Throwable error) {return ResponseResult.exception(error);}@Overridepublic boolean supports(MethodParameter method, Class<? extends HttpMessageConverter<?>> clazz) {return method.getContainingClass().getPackage().getName().startsWith("com.abc") &&(method.getContainingClass().getAnnotation(RestController.class) != null ||(method.getMethod() != null && method.getMethod().getAnnotation(ResponseBody.class) != null));}@Overridepublic Object beforeBodyWrite(Object result, MethodParameter methodParameter, MediaType mediaType,Class<? extends HttpMessageConverter<?>> aClass,ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {return result instanceof ResponseResult ? result :result instanceof Page ? ResponseResult.page((Page<?>) result) :ResponseResult.successData(result);}
}

实例

有一个Controller类，返回参数为OutputObject，我们通过ResponseBodyAdvice，对该类的所有方法返回的OutputObject中的部分数据进行统一加密处理。

// 对响应报文统一处理，对bean内容进行加密
@Component
//声明该类要处理的包路径
@ControllerAdvice("com.cmos.edcreg.web.controller")
public class ResponseAdvice implements ResponseBodyAdvice {private final Logger logger = LoggerFactory.getLogger(ResponseAdvice.class);// 对response处理的具体方法@Overridepublic Object beforeBodyWrite(Object arg0, MethodParameter arg1,MediaType arg2, Class arg3, ServerHttpRequest arg4,ServerHttpResponse arg5) {OutputObject out = new OutputObject();try {//arg0转换为OutputObject类型ObjectMapper objectMapper=new ObjectMapper();out = objectMapper.readValue(org.json.JSONObject.valueToString(arg0), OutputObject.class);//获取加密密钥String oldEncryptKey = out.getBean().get("oldEncryptKey");//获取加密字符串DesSpecial des = new DesSpecial();String encryptData = des.strEnc(JSON.toJSONString(out.getBean()), oldEncryptKey, null, null);//封装数据（清除原来数据，放入加密数据）out.getBean().clear();out.getBean().put("data", encryptData);return out;} catch (Exception e) {logger.error("返回报文处理出错", e);out.setReturnCode(ReturnInfoEnums.PROCESS_ERROR.getCode());out.setReturnMessage(ReturnInfoEnums.PROCESS_ERROR.getMessage());return out;}}/* 选择哪些类，或哪些方法需要走beforeBodyWrite* 从arg0中可以获取方法名和类名* arg0.getMethod().getDeclaringClass().getName()为获取方法名*/@Overridepublic boolean supports(MethodParameter arg0, Class arg1) {return "com.cmos.edcreg.web.controller.GdH5AppointmentActiveVideoNewController".equals(arg0.getMethod().getDeclaringClass().getName());}
}

在spring项目开发过程中的应用场景

对controller层返回值进行修改增强处理。比如返回值5，需要封装成：{“code”:“0”,“data”:5,“msg”:“success”} 格式返回前端

1、controller层业务代码

@RestController //此注解包含@ResponseBody注解
@RequestMapping("/mp")
public class ResponseBodyAdviceController {@RequestMapping(value = "/hello", method = RequestMethod.GET)public int hello() {return 5;} 
}

2、实现ResponseBodyAdvice接口的切面类

/**
*此注解针对controller层的类做增强功能，即对加了@RestController注解的类进行处理
*/
@ControllerAdvice(annotations = RestController.class)
public class RestResultWrapper implements ResponseBodyAdvice<Object> {@Overridepublic boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {return true;}@Overridepublic Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request,ServerHttpResponse response) {//定义一个统一的返回类RestResult responseResult = new RestResult( "0", body, "success");//如果handler处理类的返回类型是String（即控制层的返回值类型），为了保证一致性，这里需要将ResponseResult转回去if(body instanceof String) {return JSON.toJSONString(responseResult);}//封装后的数据返回到前端页面return JSONObject.toJSON(responseResult);       } 
}

3、返回公共类的创建

// 统一返回Rest风格的数据结构
public class RestResult<T>  implements Serializable {private String code = "2000";// 成功时返回的数据，失败时返回具体的异常信息private T data;// 请求失败返回的提示信息，给前端进行页面展示的信息private String message ; public RestResult() {}@Overridepublic String toString() {return "RestResult{" +"code='" + code + '\'' +", data=" + data +", message=" + message +'}';}public RestResult(String code, T data, String message) {this.code = code;this.data = data;this.message = message;}
}