关于Controller|关于Controller 层返回值的公共包装类的问题关于Controller层返回值的公共包

【关于Controller|关于Controller 层返回值的公共包装类的问题】场景：在微服务中，一般返回数据都会有个返回码、返回信息和返回消息体，但是每次返回时候调用或者是封装，太过麻烦，有没有什么办法不用每次都封装呢？
答案是有的。

返回值对象 ResponseData

package com.study.auth.comm; import com.alibaba.fastjson.JSON; import com.alibaba.fastjson.annotation.JSONField; import com.alibaba.fastjson.serializer.SerializerFeature; import java.io.Serializable; /** * @Package: com.study.auth.comm * @Description: <返回数据> * @Author: MILLA * @CreateDate: 2018/4/8 9:10 * @UpdateUser: MILLA * @UpdateDate: 2018/4/8 9:10 * @Version: 1.0 */public final class ResponseData implements Serializable {private static final long serialVersionUID = 7824278330465676943L; private static final String SUCCESS_CODE = "1000"; private static final String SUCCESS_MSG = "success"; /*** 响应编码*/@JSONField(serialzeFeatures = {SerializerFeature.WriteMapNullValue}, ordinal = 1)private String code; /*** 响应提示*/@JSONField(serialzeFeatures = {SerializerFeature.WriteMapNullValue}, ordinal = 2)private String msg; /*** 返回的数据*/@JSONField(serialzeFeatures = {SerializerFeature.WriteMapNullValue}, ordinal = 10)private T data; public static ResponseData success() {return initData(SUCCESS_CODE, SUCCESS_MSG, null); } public static ResponseData error(String code) {String msg = PropertiesReaderUtil.getProperty(code, null); return initData(code, msg, null); } public static ResponseData error(String code, String msg) {return initData(code, msg, null); } public static ResponseData success(T t) {return initData(SUCCESS_CODE, SUCCESS_MSG, t); } public static ResponseData errorData(String code, T data) {String msg = PropertiesReaderUtil.getProperty(code, null); return initData(code, msg, data); } public static ResponseData errorData(String code, String msg, T data) {return initData(code, msg, data); } private static ResponseData initData(String code, String msg, T t) {ResponseData data = https://www.it610.com/article/new ResponseData(SUCCESS_CODE); if (!isBlank(msg)) {data.setMsg(msg); }if (!isBlank(code)) {data.setCode(code); }if (t != null) {data.setData(t); }return data; } private static boolean isBlank(CharSequence cs) {int strLen; if (cs != null && (strLen = cs.length()) != 0) {for (int i = 0; i < strLen; ++i) {if (!Character.isWhitespace(cs.charAt(i))) {return false; }}return true; } else {return true; }} public ResponseData() {} public ResponseData(String code) {this.code = code; } public String getCode() {return code; } public void setCode(String code) {this.code = code; } public String getMsg() {return msg; } public void setMsg(String msg) {this.msg = msg; } public T getData() {return data; } public void setData(T data) {this.data = data; } @Overridepublic String toString() {return JSON.toJSONString(this); }}

文章图片

如上图的包装，还是太繁琐了。

装饰者模式使用-增强类InitializingAdviceDecorator通过实现InitializingBean和装饰者模式对Controller层的返回值进行包装，大致思路：
通过 RequestMappingHandlerAdapter获取所有的返回值处理对象 HandlerMethodReturnValueHandler创建一个新的集合存储上一步获取的集合（因为上一步的结果是unmodifiableList类型的）遍历该集合找到 HandlerMethodReturnValueHandler对象，将这个位置的handler替换程自定义的handler将新获到的集合重新设置到 RequestMappingHandlerAdapter的setReturnValueHandlers方法中

package com.study.auth.config; import com.study.auth.comm.ResponseData; import org.springframework.beans.factory.InitializingBean; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.annotation.Configuration; import org.springframework.core.MethodParameter; 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 java.util.ArrayList; import java.util.List; /** * @Package: com.study.auth.config.core * @Description: <增强controller层返回值> * @Author: milla * @CreateDate: 2020/09/04 14:42 * @UpdateUser: milla * @UpdateDate: 2020/09/04 14:42 * @UpdateRemark: <> * @Version: 1.0 */@Configurationpublic class InitializingAdviceDecorator implements InitializingBean {@Autowiredprivate RequestMappingHandlerAdapter adapter; @Overridepublic void afterPropertiesSet() {//获取所有的handler对象List returnValueHandlers = adapter.getReturnValueHandlers(); //因为上面返回的是unmodifiableList，所以需要新建list处理List handlers = new ArrayList(returnValueHandlers); this.decorateHandlers(handlers); //将增强的返回值回写回去adapter.setReturnValueHandlers(handlers); } /*** 使用自定义的返回值控制类** @param handlers*/private void decorateHandlers(List handlers) {for (HandlerMethodReturnValueHandler handler : handlers) {if (handler instanceof RequestResponseBodyMethodProcessor) {//找到返回值的handler并将起包装成自定义的handlerControllerReturnValueHandler decorator = new ControllerReturnValueHandler((RequestResponseBodyMethodProcessor) handler); int index = handlers.indexOf(handler); handlers.set(index, decorator); break; }}} /*** 自定义返回值的Handler* 采用装饰者模式*/private class ControllerReturnValueHandler implements HandlerMethodReturnValueHandler {//持有一个被装饰者对象private HandlerMethodReturnValueHandler handler; ControllerReturnValueHandler(RequestResponseBodyMethodProcessor handler) {this.handler = handler; } @Overridepublic boolean supportsReturnType(MethodParameter returnType) {return true; } /*** 增强被装饰者的功能** @param returnValue返回值* @param returnType返回类型* @param mavContainer view* @param webRequest请求对象* @throws Exception 抛出异常*/@Overridepublic void handleReturnValue(Object returnValue, MethodParameter returnType, ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception {//如果已经封装了结构体就直接放行if (returnValue instanceof ResponseData) {handler.handleReturnValue(returnValue, returnType, mavContainer, webRequest); return; }//正常返回successResponseData success = ResponseData.success(returnValue); handler.handleReturnValue(success, returnType, mavContainer, webRequest); }}}

配置文件读取类PropertiesReaderUtil

package com.study.auth.comm; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.util.Properties; /** * @Package: com.milla.navicat.comm * @Description: <读取配置properties工具类> * @Author: MILLA * @CreateDate: 2018/8/10 10:30 * @UpdateUser: MILLA * @UpdateDate: 2018/8/10 10:30 * @UpdateRemark: <> * @Version: 1.0 */public final class PropertiesReaderUtil {private static final String ENCODING = "UTF-8"; private static final Logger logger = LoggerFactory.getLogger(PropertiesReaderUtil.class); private static Properties propsZH; private static Properties propsCN; private static String name = null; static {//加载英文//loadProps(false); //加载中文loadProps(true); } /*** 第一种，通过类加载器进行获取properties文件流* 第二种，通过类进行获取properties文件流* in = PropertyUtil.class.getResourceAsStream("/properties/message_ZH.properties"); * in = PropertiesReaderUtil.class.getClassLoader().getResourceAsStream("properties/message_ZH.properties"); */synchronized static private void loadProps(boolean isZh) {logger.debug("start loading properties"); InputStream in = null; if (isZh) {propsZH = new Properties(); name = "properties/message_ZH.properties"; in = PropertiesReaderUtil.class.getClassLoader().getResourceAsStream(name); } else {propsCN = new Properties(); name = "properties/message_EN.properties"; in = PropertiesReaderUtil.class.getClassLoader().getResourceAsStream(name); }try {if (isZh) {propsZH.load(new InputStreamReader(in, ENCODING)); } else {propsCN.load(new InputStreamReader(in, ENCODING)); }} catch (Exception e) {logger.debug("loading properties error :{}", e); } finally {try {if (null != in) {in.close(); }} catch (IOException e) {logger.debug("closing properties io error :{}", e); }}} public static String getProperty(String key) {return getPropertyZH(key); } public static String getProperty(String key, String defaultValue) {return getPropertyZH(key, defaultValue); } public static String getPropertyZH(String key) {if (null == propsZH) {loadProps(true); }return propsZH.getProperty(key); } public static String getPropertyZH(String key, String defaultValue) {if (null == propsZH) {loadProps(true); }return propsZH.getProperty(key, defaultValue); } public static String getPropertyCN(String key) {if (null == propsCN) {loadProps(false); }return propsCN.getProperty(key); } public static String getPropertyCN(String key, String defaultValue) {if (null == propsCN) {loadProps(false); }return propsCN.getProperty(key, defaultValue); }}

配置文件message_ZH.properties 路径为：properties/message_ZH.properties
也可添加国家化英文或者是其他语言配置

1001=用户未登录
#====非业务返回码=========
1100=服务器内部错误
1101=空指针异常
1102=数据类型转换异常
1103=IO异常
1104=该方法找不到异常
1105=数组越界异常
1106=请求体缺失异常
1107=类型匹配异常
1108=请求参数缺失异常
1109=请求方法不支持异常
1110=请求头类型不支持异常
1111=参数解析异常
1112=必要参数不能为空
#=======================

统一异常捕捉类RestfulExceptionHandler此时，基本能保证增强Controller层的返回值了，如果有需要的话，可能通过@RestControllerAdvice注解，针对抛出的异常使用返回值对象进行包装

package com.study.auth.exception; import com.alibaba.fastjson.JSONException; import com.study.auth.comm.PropertiesReaderUtil; import com.study.auth.comm.ResponseData; import com.study.auth.constant.CommonConstant; import lombok.extern.slf4j.Slf4j; import org.springframework.beans.TypeMismatchException; import org.springframework.boot.json.JsonParseException; import org.springframework.http.converter.HttpMessageNotReadableException; import org.springframework.web.HttpMediaTypeNotSupportedException; import org.springframework.web.HttpRequestMethodNotSupportedException; import org.springframework.web.bind.MethodArgumentNotValidException; import org.springframework.web.bind.MissingServletRequestParameterException; import org.springframework.web.bind.annotation.ExceptionHandler; import org.springframework.web.bind.annotation.ResponseStatus; import org.springframework.web.bind.annotation.RestControllerAdvice; import javax.security.auth.login.AccountException; import java.io.IOException; import java.sql.SQLException; /** * @Package: com.study.auth.exception * @Description: <所有异常拦截类> * @Author: milla * @CreateDate: 2020/09/04 15:35 * @UpdateUser: milla * @UpdateDate: 2020/09/04 15:35 * @UpdateRemark: <> * @Version: 1.0 */@Slf4j@RestControllerAdvicepublic class RestfulExceptionHandler {private ResponseData responseData(String code, Exception e) {log.error("异常代码:{},异常描述:{},异常堆栈:", code, PropertiesReaderUtil.getProperty(code), e); return ResponseData.error(code); } private ResponseData responseData(String code, String message, Exception e) {log.error("异常代码:{},异常描述:{},异常堆栈:", code, message, e); return ResponseData.error(code, message); } /*** 运行时异常** @param e 异常* @return*/@ExceptionHandler(Exception.class)public ResponseData runtimeExceptionHandler(Exception e) {return responseData(CommonConstant.EX_RUN_TIME_EXCEPTION, e); } /*** 处理SQLSyntaxErrorException** @param e 异常* @return*/@ExceptionHandler(SQLException.class)public ResponseData sqlException(SQLException e) {return responseData(CommonConstant.EX_RUN_TIME_EXCEPTION, e.getMessage(), e); } /*** 处理CustomerMessageException** @param e 异常* @return*/@ExceptionHandler(CustomMessageException.class)public ResponseData customerMessageException(CustomMessageException e) {return responseData(CommonConstant.EX_RUN_TIME_EXCEPTION, e.getMessage(), e); } /*** 处理AccountException** @param e 异常* @return*/@ExceptionHandler(AccountException.class)public ResponseData accountException(AccountException e) {return responseData(e.getMessage(), e); } //---------------------------------------jdk/spring自带的异常---------------------------------- /*** 处理IllegalArgumentException** @param e 异常* @return*/@ExceptionHandler(IllegalArgumentException.class)public ResponseData illegalArgumentException(IllegalArgumentException e) {return responseData(CommonConstant.EX_RUN_TIME_EXCEPTION, e.getMessage(), e); } /*** 空指针异常** @param e 异常* @return*/@ResponseStatus@ExceptionHandler(NullPointerException.class)public ResponseData nullPointerExceptionHandler(NullPointerException e) {return responseData(CommonConstant.EX_NULL_POINTER_EXCEPTION, e); } /*** 类型转换异常** @param e 异常* @return*/@ExceptionHandler(ClassCastException.class)public ResponseData classCastExceptionHandler(ClassCastException e) {return responseData(CommonConstant.EX_CLASS_CAST_EXCEPTION, e); } /*** IO异常** @param e 异常* @return*/@ExceptionHandler(IOException.class)public ResponseData iOExceptionHandler(IOException e) {return responseData(CommonConstant.EX_IO_EXCEPTION, e); } /*** 未知方法异常** @param e 异常* @return*/@ExceptionHandler(NoSuchMethodException.class)public ResponseData noSuchMethodExceptionHandler(NoSuchMethodException e) {return responseData(CommonConstant.EX_NO_SUCH_METHOD_EXCEPTION, e); } /*** 数组越界异常** @param e 异常* @return*/@ExceptionHandler(IndexOutOfBoundsException.class)public ResponseData indexOutOfBoundsExceptionHandler(IndexOutOfBoundsException e) {return responseData(CommonConstant.EX_INDEX_OUT_OF_BOUNDS_EXCEPTION, e); } /*** 请求body缺失异常** @param e 异常* @return*/@ExceptionHandler({HttpMessageNotReadableException.class})public ResponseData requestNotReadable(HttpMessageNotReadableException e) {return responseData(CommonConstant.EX_HTTP_MESSAGE_NOT_READABLE_EXCEPTION, e); } /*** 类型匹配异常** @param e 异常* @return*/@ExceptionHandler({TypeMismatchException.class})public ResponseData requestTypeMismatch(TypeMismatchException e) {return responseData(CommonConstant.EX_HTTP_MESSAGE_NOT_READABLE_EXCEPTION, e); } /*** 方法不支持异常** @param e 异常* @return*/@ExceptionHandler({HttpRequestMethodNotSupportedException.class})public ResponseData methodNotSupported(HttpRequestMethodNotSupportedException e) {return responseData(CommonConstant.EX_HTTP_REQUEST_METHOD_NOT_SUPPORTED_EXCEPTION, e); } /*** 请求头不支持异常** @param e 异常* @return*/@ExceptionHandler({HttpMediaTypeNotSupportedException.class})public ResponseData mediaTypeNotAcceptable(HttpMediaTypeNotSupportedException e) {return responseData(CommonConstant.EX_HTTP_MEDIA_TYPE_NOT_ACCEPTABLE_EXCEPTION, e); } /*** 参数解析异常** @param e 异常* @return*/@ExceptionHandler(JSONException.class)public ResponseData runtimeExceptionHandler(JSONException e) {return responseData(CommonConstant.PARAMS_PARSE_EXCEPTION, e); } /*** 参数解析异常** @param e 异常* @return*/@ExceptionHandler(JsonParseException.class)public ResponseData runtimeExceptionHandler(JsonParseException e) {return responseData(CommonConstant.PARAMS_PARSE_EXCEPTION, e); } /*** 请求参数缺失异常** @param e 异常* @return*/ @ExceptionHandler({MissingServletRequestParameterException.class})public ResponseData requestMissingServletRequest(MissingServletRequestParameterException e) {return responseData(CommonConstant.EX_MISSING_SERVLET_REQUEST_PARAMETER_EXCEPTION, e); } /*** 参数不能为空** @param e 异常* @return*/@ExceptionHandler(MethodArgumentNotValidException.class)public ResponseData exceptionHandler(MethodArgumentNotValidException e) {return responseData(CommonConstant.PARAMS_IS_NULL, e); }}

常量类 CommonConstant

package com.study.auth.constant; /** * @Package: com.study.auth.constant * @Description: <公共常量类> * @Author: milla * @CreateDate: 2020/09/04 15:37 * @UpdateUser: milla * @UpdateDate: 2020/09/04 15:37 * @UpdateRemark: <> * @Version: 1.0 */public final class CommonConstant {/*** 当前用户名称*/public static final String C_CURRENT_ACCOUNT = "current_account"; /*** 用户未登录*/public static final String EX_NO_TOKEN_EXCEPTION = "1001"; //--------------------------------非业务返回码---------------------------------------/*** 运行时异常*/public static final String EX_RUN_TIME_EXCEPTION = "1100"; /*** 空指针异常*/public static final String EX_NULL_POINTER_EXCEPTION = "1101"; /*** 数据转换异常*/public static final String EX_CLASS_CAST_EXCEPTION = "1102"; /*** IO异常*/public static final String EX_IO_EXCEPTION = "1103"; /*** 找不到该方法异常*/public static final String EX_NO_SUCH_METHOD_EXCEPTION = "1104"; /*** 数组越界异常*/public static final String EX_INDEX_OUT_OF_BOUNDS_EXCEPTION = "1105"; /*** 请求体缺失异常*/public static final String EX_HTTP_MESSAGE_NOT_READABLE_EXCEPTION = "1106"; /*** TYPE匹配异常*/public static final String EX_TYPE_MISMATCH_EXCEPTION = "1107"; /*** 请求参数丢失*/public static final String EX_MISSING_SERVLET_REQUEST_PARAMETER_EXCEPTION = "1108"; /*** 请求方法类型不支持异常*/public static final String EX_HTTP_REQUEST_METHOD_NOT_SUPPORTED_EXCEPTION = "1109"; /*** MEDIA 类型不支持异常*/public static final String EX_HTTP_MEDIA_TYPE_NOT_ACCEPTABLE_EXCEPTION = "1110"; /*** 参数解析异常*/public static final String PARAMS_PARSE_EXCEPTION = "1111"; /*** 参数不能为空*/public static final String PARAMS_IS_NULL = "1112"; //-----------------------------------------------------------------------------------}

自定义异常类 CustomMessageException

package com.study.auth.exception; /** * @Package: com.study.auth.exception * @Description: <自定义异常类> * @Author: MILLA * @CreateDate: 2019/8/15 18:39 * @UpdateUser: MILLA * @UpdateDate: 2019/8/15 18:39 * @UpdateRemark: <> * @Version: 1.0 */public class CustomMessageException extends RuntimeException { public CustomMessageException() {super(); } public CustomMessageException(String message) {super(message); } public CustomMessageException(String message, Throwable cause) {super(message, cause); } public CustomMessageException(Throwable cause) {super(cause); } protected CustomMessageException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {super(message, cause, enableSuppression, writableStackTrace); }}