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 {

    @Override
    public Object beforeBodyWrite(Object o, MethodParameter methodParameter, MediaType mediaType, Class aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) {

        System.out.println("TestResponseBodyAdvice==>beforeBodyWrite:" + o.toString() + ","
                + methodParameter);
        return o;
    }

    @Override
    public 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);
    }

    @Override
    public 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));
    }

    @Override
    public 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
    @Override
    public 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 */
    @Override
    public 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> {
    @Override
    public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
        return true;
    }
 
    @Override
    public 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() {
    }
 
    @Override
    public 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;
    }
}