定义通用的返回对象--返回错误信息

README.md

@@ -43,3 +43,5 @@
 **Tips:** Model与Data Object并非完全一一对应，例如UserModel是由ServiceImpl将UserDO和UserPasswordDO组装而成的。
 
 response: 用于处理HTTP请求返回
+
+error: 用于返回错误信息

src/main/java/com/cxyxiaomo/flashsale/controller/UserController.java

@@ -1,6 +1,8 @@
 package com.cxyxiaomo.flashsale.controller;
 
 import com.cxyxiaomo.flashsale.controller.viewobject.UserVO;
+import com.cxyxiaomo.flashsale.error.BusinessException;
+import com.cxyxiaomo.flashsale.error.EmBusinessError;
 import com.cxyxiaomo.flashsale.response.CommonReturnType;
 import com.cxyxiaomo.flashsale.service.UserService;
 import com.cxyxiaomo.flashsale.service.model.UserModel;
@@ -21,9 +23,14 @@ public class UserController {
 
     @RequestMapping("/get")
     @ResponseBody
-    public CommonReturnType getUser(@RequestParam(name = "id") Integer id) {
+    public CommonReturnType getUser(@RequestParam(name = "id") Integer id) throws BusinessException {
         // 调用Services服务获取对应id的用户对象并返回给前端
         UserModel userModel = userService.getUserById(id);
+
+        // 若获取的用户信息不存在
+        if(userModel==null){
+            throw new BusinessException(EmBusinessError.USER_NOT_EXIST);
+        }
         // 将核心领域模型用户对象转化为可供UI使用的viewobject
         UserVO userVO = convertFromModel(userModel);
 

src/main/java/com/cxyxiaomo/flashsale/error/BusinessException.java

@@ -0,0 +1,37 @@
+package com.cxyxiaomo.flashsale.error;
+
+/**
+ * 包装器业务异常类实现
+ */
+public class BusinessException extends Exception implements CommonError {
+
+    private CommonError commonError;
+
+    public BusinessException(CommonError commonError) {
+        super();
+        this.commonError = commonError;
+    }
+
+    // 接收自定义errMsg的方式构造业务异常
+    public BusinessException(CommonError commonError,String errMsg){
+        super();
+        this.commonError=commonError;
+        this.commonError.setErrMsg(errMsg);
+    }
+
+    @Override
+    public int getErrCode() {
+        return this.commonError.getErrCode();
+    }
+
+    @Override
+    public String getErrMsg() {
+        return this.commonError.getErrMsg();
+    }
+
+    @Override
+    public CommonError setErrMsg(String errMsg) {
+        this.commonError.setErrMsg(errMsg);
+        return this;
+    }
+}

src/main/java/com/cxyxiaomo/flashsale/error/CommonError.java

@@ -0,0 +1,7 @@
+package com.cxyxiaomo.flashsale.error;
+
+public interface CommonError {
+    public int getErrCode();
+    public String getErrMsg();
+    public CommonError setErrMsg(String errMsg);
+}

src/main/java/com/cxyxiaomo/flashsale/error/EmBusinessError.java

@@ -0,0 +1,35 @@
+package com.cxyxiaomo.flashsale.error;
+
+public enum EmBusinessError implements CommonError {
+    // 通用错误类型 00001
+    PARAMETER_VALIDATION_ERROR(00001,"参数不合法"),
+
+    // 10000开头为用户信息相关错误定义
+    USER_NOT_EXIST(10001, "用户不存在");
+
+    private EmBusinessError(int errCode, String errMsg) {
+        this.errCode = errCode;
+        this.errMsg = errMsg;
+    }
+
+    private int errCode;
+    private String errMsg;
+
+
+    @Override
+    public int getErrCode() {
+        return this.errCode;
+    }
+
+    @Override
+    public String getErrMsg() {
+        return this.errMsg;
+    }
+
+    @Override
+    public CommonError setErrMsg(String errMsg) {
+        this.errCode = errCode;
+        this.errMsg = errMsg;
+        return this;
+    }
+}