装饰SpringMVC的适配器实现响应自动包装

1.common-tool-starter

1.目录结构

2.ResultWrapper.java

package com.sunxiansheng.tool.response;import lombok.Data;import java.io.Serializable;/*** Description: 通用响应封装类，通过枚举来获取code和message** @Author sun* @Create 2024/10/11* @Version 1.0*/
@Data
public class ResultWrapper<T> implements Serializable {private static final long serialVersionUID = 1L;// 是否成功private boolean success;// 响应代码private int code;// 响应消息private String message;// 响应数据private T data;// 私有构造器，防止外部直接创建private ResultWrapper() {}// 使用内部建造者类进行对象构建public static class Builder<T> {private boolean success;private int code;private String message;private T data;// ============================== 链式调用设置建造者对象 ==============================public Builder<T> success(boolean success) {this.success = success;return this;}public Builder<T> code(int code) {this.code = code;return this;}public Builder<T> message(String message) {this.message = message;return this;}public Builder<T> data(T data) {this.data = data;return this;}// ============================== 链式调用设置建造者对象 ==============================// ============================== 构建ResultWrapper对象 ==============================public ResultWrapper<T> build() {ResultWrapper<T> result = new ResultWrapper<>();result.success = this.success;result.code = this.code;result.message = this.message;result.data = this.data;return result;}// ============================== 构建ResultWrapper对象 ==============================}// ============================== 快捷方法 ==============================public static <T> ResultWrapper<T> ok() {return new Builder<T>().success(true).code(RespBeanEnum.SUCCESS.getCode()).message(RespBeanEnum.SUCCESS.getMessage()).build();}public static <T> ResultWrapper<T> ok(T data) {return new Builder<T>().success(true).code(RespBeanEnum.SUCCESS.getCode()).message(RespBeanEnum.SUCCESS.getMessage()).data(data).build();}public static <T> ResultWrapper<T> ok(T data, String message) {return new Builder<T>().success(true).code(RespBeanEnum.SUCCESS.getCode()).message(message).data(data).build();}public static <T> ResultWrapper<T> fail() {return new Builder<T>().success(false).code(RespBeanEnum.ERROR.getCode()).message(RespBeanEnum.ERROR.getMessage()).build();}public static <T> ResultWrapper<T> fail(String message) {return new Builder<T>().success(false).code(RespBeanEnum.ERROR.getCode()).message(message).build();}public static <T> ResultWrapper<T> fail(int code, String message) {return new Builder<T>().success(false).code(code).message(message).build();}public static <T> ResultWrapper<T> fail(int code, String message, T data) {return new Builder<T>().success(false).code(code).message(message).data(data).build();}public static <T> ResultWrapper<T> fail(RespBeanEnum respBeanEnum) {return new Builder<T>().success(false).code(respBeanEnum.getCode()).message(respBeanEnum.getMessage()).build();}// ============================== 快捷方法 ==============================
}

2.common-web-starter

1.目录结构

2.IgnoredResultWrapper.java 自定义注解，忽略对返回结果的自动包装

package com.sunxiansheng.web.annotation;import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;/*** Description: 忽略对返回结果的自动包装** @Author sun* @Create 2025/1/6 15:58* @Version 1.0*/
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface IgnoredResultWrapper {}

3.ReturnValueHandlersDecorator.java 对适配器进行扩展的装饰器

package com.sunxiansheng.web.config;import com.sunxiansheng.tool.response.ResultWrapper;
import com.sunxiansheng.web.annotation.IgnoredResultWrapper;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.core.MethodParameter;
import org.springframework.core.annotation.AnnotatedElementUtils;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
import org.springframework.web.method.support.ModelAndViewContainer;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
import org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor;import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;/*** Description: 装饰器** @Author sun* @Create 2025/1/6 14:40* @Version 1.0*/
@Slf4j
public class ReturnValueHandlersDecorator implements InitializingBean {/*** 注入适配器，可以获取*/@Resourceprivate RequestMappingHandlerAdapter requestMappingHandlerAdapter;@Overridepublic void afterPropertiesSet() {List<HandlerMethodReturnValueHandler> returnValueHandlers = requestMappingHandlerAdapter.getReturnValueHandlers();// 因为默认List<HandlerMethodReturnValueHandler>是不可修改列表，所以需要给他转换成一个可修改的列表assert returnValueHandlers != null;List<HandlerMethodReturnValueHandler> handlers = new ArrayList<>(returnValueHandlers);// 装饰一下然后重新设置this.decorateHandlers(handlers);// 将装饰后的handlers替换原来的不可变列表requestMappingHandlerAdapter.setReturnValueHandlers(handlers);}private void decorateHandlers(List<HandlerMethodReturnValueHandler> returnValueHandlers) {for (HandlerMethodReturnValueHandler returnValueHandler : returnValueHandlers) {if (returnValueHandler instanceof RequestResponseBodyMethodProcessor) {// 找到RequestResponseBodyMethodProcessorControllerReturnValueHandler controllerReturnValueHandler = new ControllerReturnValueHandler(returnValueHandler);// 找到在原列表中的索引位置int index = returnValueHandlers.indexOf(returnValueHandler);// 将装饰后的HandlerMethodReturnValueHandler放到原来的位置returnValueHandlers.set(index, controllerReturnValueHandler);}}}private static class ControllerReturnValueHandler implements HandlerMethodReturnValueHandler {// 拿到被装饰的对象private final HandlerMethodReturnValueHandler handler;public ControllerReturnValueHandler(HandlerMethodReturnValueHandler handler) {this.handler = handler;}/*** 保持跟原生的一致** @param returnType* @return*/@Overridepublic boolean supportsReturnType(MethodParameter returnType) {return AnnotatedElementUtils.hasAnnotation(returnType.getContainingClass(), ResponseBody.class) || returnType.hasMethodAnnotation(ResponseBody.class);}@Overridepublic void handleReturnValue(Object o, MethodParameter methodParameter, ModelAndViewContainer modelAndViewContainer, NativeWebRequest nativeWebRequest) throws Exception {IgnoredResultWrapper methodAnnotation = methodParameter.getMethodAnnotation(IgnoredResultWrapper.class);// 如果有IgnoredResultWrapper注解，就不进行包装，走原来的逻辑if (Objects.nonNull(methodAnnotation)) {handler.handleReturnValue(o, methodParameter, modelAndViewContainer, nativeWebRequest);return;}// 如果返回值是ResultWrapper类型，也不进行包装，走原来的逻辑if (o instanceof ResultWrapper) {handler.handleReturnValue(o, methodParameter, modelAndViewContainer, nativeWebRequest);return;}// 其余情况，进行包装log.info("Controller返回值已被自动包装，如果上传文件，请加@IgnoredResultWrapper注解取消自动包装！");ResultWrapper<Object> ok = ResultWrapper.ok(o);handler.handleReturnValue(ok, methodParameter, modelAndViewContainer, nativeWebRequest);}}
}

4.WebAutoConfiguration.java 将装饰器注入容器

    /*** 注入对返回结果增强的装饰器** @return*/@Bean@ConditionalOnMissingBeanpublic ReturnValueHandlersDecorator returnValueHandlersDecorator() {return new ReturnValueHandlersDecorator();}

3.common-web-starter-demo

1.WebController.java 测试三种使用方式

package com.sunxiansheng.web.controller;import com.sunxiansheng.tool.response.ResultWrapper;
import com.sunxiansheng.web.annotation.IgnoredResultWrapper;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;/*** Description: 测试** @Author sun* @Create 2024/10/4 22:56* @Version 1.0*/
@RestController
public class WebController {/*** 第一种方式：直接使用自动包装成功结果** @return*/@RequestMapping("/method1")public String method1() {return "method1";}/*** 第二种方式：使用 @IgnoredResultWrapper注解忽略掉自动包装** @return*/@IgnoredResultWrapper@RequestMapping("/method2")public String method2() {return "method2";}/*** 第三种方式：直接使用ResultWrapper来自己封装结果** @return*/@RequestMapping("/method3")public ResultWrapper<String> method3() {return ResultWrapper.fail("method3");}
}

2.测试

1.第一种：直接使用自动包装成功结果

2.第二种：使用 @IgnoredResultWrapper注解忽略掉自动包装

3.第三种：直接使用ResultWrapper来自己封装结果