一、統一處理返回結果和異常處理的原因：
1、在springboot項目里我們希望接口返回的數據包含至少三個屬性：
a、code：請求接口的返回碼，成功或者異常等返回編碼，例如定義請求成功，code = "0000",查詢結果為null，code = "0001";
b、msg：請求接口的描述，也就是對返回編碼的描述，"0000"：就表示請求成功，"0001"：表示結果為null；
c、data：請求接口成功，返回的結果。
-
{
-
"data": {
-
"id":
1,
-
"studentId":
"13240115",
-
"name":
"Tiger",
-
"age":
25,
-
"famillyAddress":
"北京",
-
"createdDate":
"2018-10-08T05:45:49.000+0000",
-
"updatedDate":
"2018-10-09T03:15:33.000+0000"
-
},
-
"code":
"0000",
-
"msg":
"請求成功"
-
}
2、在springboot項目里我們希望請求結果失敗之后，通過返回碼和返回描述來告訴前端接口請求異常。
-
{
-
"code":
"0001",
-
"msg":
"學號不存在"
-
}
二、案例
1、建一張學生信息表，包含學生的學號、姓名、年齡、家庭住址等
-
CREATE
TABLE student_info (
-
id
bigint(
20)
NOT
NULL AUTO_INCREMENT
COMMENT
'自增',
-
student_id
varchar(
20)
NOT
NULL
COMMENT
'學號',
-
name
varchar(
64)
NOT
NULL
COMMENT
'姓名',
-
age
int(
2)
NOT
NULL
COMMENT
'年齡',
-
familly_address
varchar(
256)
NOT
NULL
COMMENT
'家庭地址',
-
created_date datetime
NOT
NULL
DEFAULT
CURRENT_TIMESTAMP
COMMENT
'創建時間',
-
updated_date datetime
NOT
NULL
DEFAULT
CURRENT_TIMESTAMP
COMMENT
'更新時間',
-
PRIMARY
KEY (student_id),
-
KEY
id (
id)
-
)
ENGINE=
InnoDB
DEFAULT
CHARSET=utf8mb4
2、pom.xml
-
<dependencies>
-
<dependency>
-
<groupId>org.springframework.boot
</groupId>
-
<artifactId>spring-boot-starter-web
</artifactId>
-
</dependency>
-
-
<dependency>
-
<groupId>org.springframework.boot
</groupId>
-
<artifactId>spring-boot-starter-test
</artifactId>
-
<scope>test
</scope>
-
</dependency>
-
-
<dependency>
-
<groupId>org.springframework.boot
</groupId>
-
<artifactId>spring-boot-starter-data-redis
</artifactId>
-
</dependency>
-
-
<dependency>
-
<groupId>org.mybatis.spring.boot
</groupId>
-
<artifactId>mybatis-spring-boot-starter
</artifactId>
-
<version>1.3.1
</version>
-
</dependency>
-
-
<dependency>
-
<groupId>mysql
</groupId>
-
<artifactId>mysql-connector-java
</artifactId>
-
<version>5.1.46
</version>
-
</dependency>
-
-
<dependency>
-
<groupId>com.alibaba
</groupId>
-
<artifactId>druid
</artifactId>
-
<version>1.1.9
</version>
-
</dependency>
-
-
<dependency>
-
<groupId>org.projectlombok
</groupId>
-
<artifactId>lombok
</artifactId>
-
<version>1.16.22
</version>
-
</dependency>
-
-
<dependency>
-
<groupId>com.alibaba
</groupId>
-
<artifactId>fastjson
</artifactId>
-
<version>1.2.43
</version>
-
</dependency>
-
-
-
<dependency>
-
<groupId>com.squareup.okhttp3
</groupId>
-
<artifactId>okhttp
</artifactId>
-
<version>3.9.1
</version>
-
</dependency>
-
-
<dependency>
-
<groupId>org.glassfish
</groupId>
-
<artifactId>javax.json
</artifactId>
-
<version>1.0.4
</version>
-
</dependency>
-
-
<dependency>
-
<groupId>org.apache.tomcat.embed
</groupId>
-
<artifactId>tomcat-embed-jasper
</artifactId>
-
</dependency>
-
-
</dependencies>
3、案例中使用redis進行緩存，可以不需要
4、創建實體類：StudentInfo
-
package com.dl.cn.message.bean;
-
-
import lombok.AllArgsConstructor;
-
import lombok.Builder;
-
import lombok.Data;
-
import lombok.NoArgsConstructor;
-
-
import java.io.Serializable;
-
import java.util.Date;
-
-
/**
-
* Created by Tiger on 2018/10/8.
-
*/
-
@Data
-
@Builder
-
@AllArgsConstructor
-
@NoArgsConstructor
-
public
class StudentInfo implements Serializable{
-
-
private
static
final
long serialVersionUID =
2597547944454691103L;
-
-
private Long id;
-
private String studentId;
-
private String name;
-
private Integer age;
-
private String famillyAddress;
-
private Date createdDate;
-
private Date updatedDate;
-
}
5、創建Mapper：StudentInfoMapper
-
package com.dl.cn.message.mapper;
-
-
import com.dl.cn.message.bean.StudentInfo;
-
import org.apache.ibatis.annotations.*;
-
-
/**
-
* Created by Tiger on 2018/10/8.
-
*/
-
@Mapper
-
public
interface StudentInfoMapper {
-
@Insert("insert into student_info(student_id,name,age,familly_address)" +
-
" values(#{studentId},#{name},#{age},#{famillyAddress})")
-
/**
-
* 通過bean保存實體類是，建議不要通過@Param注解，負責實體類的屬性都在@Param中找
-
* */
-
void saveStudentInfo(StudentInfo studentInfo);
-
-
-
@Select("select * from student_info where student_id = #{studentId}")
-
StudentInfo findByStudentId(
@Param("studentId") String studentId);
-
-
-
@Update("update student_info set familly_address = #{famillyAddress},updated_date = now() ")
-
void updateFamillyAddress(
@Param("studentId") String studentId,
@Param("famillyAddress") String famillyAddress);
-
}
6、創建service：StudentInfoService
-
package com.dl.cn.message.service;
-
-
import com.dl.cn.message.bean.StudentInfo;
-
import com.dl.cn.message.mapper.StudentInfoMapper;
-
import lombok.extern.slf4j.Slf4j;
-
import org.springframework.beans.factory.
annotation.Autowired;
-
import org.springframework.cache.
annotation.CacheConfig;
-
import org.springframework.cache.
annotation.CacheEvict;
-
import org.springframework.cache.
annotation.Cacheable;
-
import org.springframework.stereotype.Service;
-
-
/**
-
* Created by Tiger on 2018/10/8.
-
*/
-
@Service
-
@CacheConfig(cacheNames = "studentInfo")
-
@Slf4j
-
public
class StudentInfoService {
-
-
@Autowired
-
StudentInfoMapper studentInfoMapper;
-
-
/**
-
* 保存學生信息
-
* @param studentInfo
-
* */
-
public void saveStudentInfo(StudentInfo studentInfo){
-
studentInfoMapper.saveStudentInfo(studentInfo);
-
}
-
-
/**
-
* 根據學號查學生信息
-
* @param studentId
-
* @return
-
* */
-
@Cacheable(key = "#studentId",unless = "#result == null")
-
public StudentInfo findByStudentId(String studentId){
-
log.info(
"查找信息:{}",studentId);
-
return studentInfoMapper.findByStudentId(studentId);
-
}
-
-
/**
-
* 根據學號更新家庭地址
-
* @param studentId
-
* @param famillyAddress
-
* */
-
//刪除對應key的緩存
-
@CacheEvict(key = "#studentId")
-
public void updateFamillyAddress(String studentId,String famillyAddress){
-
studentInfoMapper.updateFamillyAddress(studentId,famillyAddress);
-
}
-
}
7、創建統一返回結果類：Response
-
package com.dl.cn.message.response;
-
-
import com.fasterxml.jackson.databind.
annotation.JsonSerialize;
-
import lombok.Getter;
-
import lombok.Setter;
-
-
import java.io.Serializable;
-
-
/**
-
* 請求返回類
-
* Created by Tiger on 2018/10/9.
-
*/
-
@Getter
-
@Setter
-
@JsonSerialize(include= JsonSerialize.Inclusion.NON_NULL)
-
public
class Response<T> implements Serializable {
-
-
private static
final long serialVersionUID =
-4505655308965878999L;
-
-
//請求成功返回碼為：0000
-
private static
final String successCode =
"0000";
-
//返回數據
-
private T
data;
-
//返回碼
-
private String code;
-
//返回描述
-
private String msg;
-
-
public Response(){
-
this.code = successCode;
-
this.msg =
"請求成功";
-
}
-
-
public Response(String code,String msg){
-
this();
-
this.code = code;
-
this.msg = msg;
-
}
-
public Response(String code,String msg,T
data){
-
this();
-
this.code = code;
-
this.msg = msg;
-
this.
data =
data;
-
}
-
public Response(T
data){
-
this();
-
this.
data =
data;
-
}
-
}
8、創建異常編碼和描述類：ErrorCodeAndMsg
-
package com.dl.cn.message.enums;
-
-
/**
-
* Created by Tiger on 2018/10/9.
-
*/
-
public
enum ErrorCodeAndMsg {
-
-
Student_number_does_not_exist(
"0001",
"學號不存在"),
-
Insufficient_student_number(
"0002",
"學號長度不足"),
-
Student_number_is_empty(
"0003",
"學號為空"),
-
Network_error(
"9999",
"網絡錯誤，待會重試"),
-
;
-
-
private String code;
-
private String msg;
-
-
ErrorCodeAndMsg(String code, String msg) {
-
this.code = code;
-
this.msg = msg;
-
}
-
-
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;
-
}
-
}
9、創建統一異常處理類：StudentException
-
package com.dl.cn.message.exception;
-
-
import com.dl.cn.message.enums.ErrorCodeAndMsg;
-
-
import java.io.Serializable;
-
-
/**
-
* 統一異常捕獲類
-
* Created by Tiger on 2018/10/9.
-
*/
-
public
class StudentException extends RuntimeException{
-
-
private
static
final
long serialVersionUID = -
6370612186038915645L;
-
-
private
final ErrorCodeAndMsg response;
-
-
public StudentException(ErrorCodeAndMsg response) {
-
this.response = response;
-
}
-
public ErrorCodeAndMsg getResponse() {
-
return response;
-
}
-
}
10、創建異常處理的全局配置類：ExceptionHandler
-
package com.dl.cn.message.exception;
-
-
import com.dl.cn.message.enums.ErrorCodeAndMsg;
-
import com.dl.cn.message.
response.
Response;
-
import lombok.extern.slf4j.Slf4j;
-
import org.springframework.web.bind.annotation.ControllerAdvice;
-
import org.springframework.web.bind.annotation.ResponseBody;
-
-
import javax.servlet.http.HttpServletRequest;
-
-
/**
-
* Created by Tiger
on
2018/
10/
9.
-
*/
-
@ControllerAdvice
-
@Slf4j
-
public
class ExceptionHandler {
-
@org.springframework.web.bind.annotation.ExceptionHandler(StudentException.
class)
-
@ResponseBody
-
public
Response handleStudentException(HttpServletRequest
request, StudentException ex) {
-
Response
response;
-
log.
error(
"StudentException code:{},msg:{}",ex.getResponse().getCode(),ex.getResponse().getMsg());
-
response =
new
Response(ex.getResponse().getCode(),ex.getResponse().getMsg());
-
return
response;
-
}
-
@org.springframework.web.bind.annotation.ExceptionHandler(Exception.
class)
-
@ResponseBody
-
public
Response handleException(HttpServletRequest
request, Exception ex) {
-
Response
response;
-
log.
error(
"exception error:{}",ex);
-
response =
new
Response(ErrorCodeAndMsg.Network_error.getCode(),
-
ErrorCodeAndMsg.Network_error.getMsg());
-
return
response;
-
}
-
}
11、創建controler類：StudentInofController
-
package com.dl.cn.message.controller;
-
-
import com.dl.cn.message.enums.ErrorCodeAndMsg;
-
import com.dl.cn.message.exception.StudentException;
-
import com.dl.cn.message.response.Response;
-
import com.dl.cn.message.service.StudentInfoService;
-
import com.dl.cn.message.bean.StudentInfo;
-
import lombok.extern.slf4j.Slf4j;
-
import org.springframework.beans.factory.
annotation.Autowired;
-
import org.springframework.web.bind.
annotation.PostMapping;
-
import org.springframework.web.bind.
annotation.RequestMapping;
-
import org.springframework.web.bind.
annotation.RequestParam;
-
import org.springframework.web.bind.
annotation.RestController;
-
-
/**
-
* Created by Tiger on 2018/10/8.
-
*/
-
@RestController
-
@RequestMapping("/student")
-
@Slf4j
-
public
class StudentInofController {
-
@Autowired
-
StudentInfoService studentInfoService;
-
-
/**
-
* 保存學生信息
-
* @param studentId
-
* @param name
-
* @param age
-
* @param famillyAddress
-
* */
-
@PostMapping("/save")
-
public void saveStudentInfo(
@RequestParam("student_id") String studentId,
-
@RequestParam("name") String name,
-
@RequestParam("age") Integer age,
-
@RequestParam("familly_address") String famillyAddress){
-
StudentInfo studentInfo = StudentInfo.builder()
-
.studentId(studentId)
-
.name(name)
-
.age(age)
-
.famillyAddress(famillyAddress)
-
.build();
-
studentInfoService.saveStudentInfo(studentInfo);
-
}
-
-
/**
-
* 根據學號查學生信息
-
* @param studentId
-
* @return
-
* */
-
@PostMapping("/findByStudentId")
-
public Response findByStudentId(
@RequestParam("student_id") String studentId){
-
try{
-
log.info(
"Get student information based on student number:{}",studentId);
-
if(studentId ==
null){
-
throw new StudentException(ErrorCodeAndMsg.Student_number_is_empty);
-
}
-
//學號固定為8位
-
if(studentId.length() !=
8){
-
throw new StudentException(ErrorCodeAndMsg.Insufficient_student_number);
-
}
-
StudentInfo studentInfo = studentInfoService.findByStudentId(studentId);
-
if(studentInfo ==
null){
-
throw new StudentException(ErrorCodeAndMsg.Student_number_does_not_exist);
-
}
-
return new Response(studentInfo);
-
}
catch (Exception e){
-
if(e instanceof StudentException){
-
throw e;
-
}
else {
-
log.error(
"findByStudentId error:",e);
-
throw new StudentException(ErrorCodeAndMsg.Network_error);
-
}
-
}
-
}
-
-
@PostMapping("/updateFamillyAddress")
-
public Response updateFamillyAddress(
@RequestParam("student_id") String studentId,
-
@RequestParam("familly_address") String famillyAddress){
-
studentInfoService.updateFamillyAddress(studentId,famillyAddress);
-
Response response = new Response();
-
System.
out.println(response.toString());
-
return response;
-
}
-
-
-
}
12、application.properties配置
-
#redis
-
spring.redis.host=
127.0
.0
.1
-
spring.redis.port=
6379
-
spring.redis.password=tiger
-
-
#mybatis
-
#開啟mybatis駝峰命名，這樣可以將mysql中帶有下划線的映射成駝峰命名的字段
-
mybatis.configuration.map-underscore-to-camel-
case=
true
-
-
#datasource
-
spring.datasource.url=jdbc:mysql:
//127.0.0.1:3306/tiger?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&autoReconnect=true&generateSimpleParameterMetadata=true
-
spring.datasource.username=tiger
-
spring.datasource.password=tiger
-
spring.datasource.driver-
class-name=com.mysql.jdbc.Driver
-
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
-
spring.datasource.max-idle=
10
-
spring.datasource.max-wait=
60000
-
spring.datasource.min-idle=
5
-
spring.datasource.initial-size=
5
-
spring.datasource.validationQuery=select
'x'
三、說明
1、controller層使用注解@RestController，這樣返回結果就是json格式，而@Controller返回結果是字符串
2、throw 異常
如果exception類型是自定義的異常StudentException，直接拋出，如果是其它異常統一拋出網絡錯誤
-
try{
-
-
}
catch (
Exception e){
-
if(e
instanceof StudentException){
-
throw e;
-
}
else {
-
log.error(
"findByStudentId error:",e);
-
throw
new StudentException(ErrorCodeAndMsg.Network_error);
-
}
-
}
3、在返回結果類添加了注解@JsonSerialize(include= JsonSerialize.Inclusion.NON_NULL)
是因為更新或者刪除操作，一般沒有返回值，我只需要知道是否更新成功或者刪除成功就OK了，如果不加這個注解
我們返回的結果中data為null！！！
-
{
-
"data":
null,
-
"code":
"0000",
-
"msg":
"請求成功"
-
}
加上注解再更新數據，返回結果：
-
{
-
"code":
"0000",
-
"msg":
"請求成功"
-
}
因此這個注解的作用就是：返回結果中有null值，干掉它！
四、測試結果
mysql數據庫中有一條學號為13240115的數據：
1、student_id = "13240115"時
-
{
-
"data": {
-
"id":
1,
-
"studentId":
"13240115",
-
"name":
"Tiger",
-
"age":
25,
-
"famillyAddress":
"北京",
-
"createdDate":
"2018-10-08T05:45:49.000+0000",
-
"updatedDate":
"2018-10-09T05:36:36.000+0000"
-
},
-
"code":
"0000",
-
"msg":
"請求成功"
-
}
2、student_id = "13240114"時
-
{
-
"code":
"0001",
-
"msg":
"學號不存在"
-
}
3、student_id = "1324011"，不足8位時
-
{
-
"code":
"0002",
-
"msg":
"學號長度不足"
-
}
4、student_id = "13240115"，然后在接口中加上一行代碼，System.out.println(1/0);
返回結果：
-
{
-
"code":
"9999",
-
"msg":
"網絡錯誤，待會重試"
-
}
控制台日志：
-
java.lang.
ArithmeticException: / by zero
-
at com.dl.cn.message.controller.
StudentInofController.findByStudentId(
StudentInofController.java:
54) ~[classes/:na]
-
at sun.
reflect.
NativeMethodAccessorImpl.invoke0(
Native
Method) ~[na:
1.8.
0_161]
-
at sun.
reflect.
NativeMethodAccessorImpl.invoke(
NativeMethodAccessorImpl.java:
62) ~[na:
1.8.
0_161]
-
at sun.
reflect.
DelegatingMethodAccessorImpl.invoke(
DelegatingMethodAccessorImpl.java:
43) ~[na:
1.8.
0_161]
-
at java.lang.
reflect.
Method.invoke(
Method.java:
498) ~[na:
1.8.
0_161]
-
at org.springframework.web.method.support.
InvocableHandlerMethod.doInvoke(
InvocableHandlerMethod.java:
209) [spring-web-
5.0.
8.
RELEASE.jar:
5.0.
8.
RELEASE]
-
at org.springframework.web.method.support.
InvocableHandlerMethod.invokeForRequest(
InvocableHandlerMethod.java:
136) [spring-web-
5.0.
8.
RELEASE.jar:
5.0.
8.
RELEASE]
通過測試，發現這個小案例滿足剛開始我們提出的需求，一定還有很多其它問題，暫時沒有發現，我會及時修改，不知道有人是否看我的博客？我只是想把自己的學習成果總結記錄下來。人可以成長為芳草，也可以長成雜莠！！！
原文地址：https://blog.csdn.net/qq_31289187/article/details/82980714