目录
3、通过HandlerExceptionResovler接口实现全局异常
4、使用@ControllerAdvice+@ExceptionHandler实现全局异常
一、SpringMVC对JSON的支持
1、pom依赖
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.3</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.9.3</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>2.9.3</version>
</dependency>
2、Springmvc.xml配置
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
<property name="messageConverters">
<list>
<ref bean="mappingJackson2HttpMessageConverter"/>
</list>
</property>
</bean>
<bean id="mappingJackson2HttpMessageConverter"
class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<!--处理中文乱码以及避免IE执行AJAX时，返回JSON出现下载文件-->
<property name="supportedMediaTypes">
<list>
<value>text/html;charset=UTF-8</value>
<value>text/json;charset=UTF-8</value>
<value>application/json;charset=UTF-8</value>
</list>
</property>
</bean>
3、后台代码
①ClazzBiz
package com.liaoxin.ssm.biz;
import com.liaoxin.ssm.model.Clazz;
import com.liaoxin.ssm.util.PageBean;
import java.util.List;
import java.util.Map;
public interface ClazzBiz {
int deleteByPrimaryKey(Integer cid);
int insert(Clazz record);
int insertSelective(Clazz record);
Clazz selectByPrimaryKey(Integer cid);
int updateByPrimaryKeySelective(Clazz record);
int updateByPrimaryKey(Clazz record);
List<Clazz> listPager(Clazz clazz, PageBean pageBean);
List<Map> listMapPager(Clazz clazz, PageBean pageBean);
}
②ClazzBizImpl
package com.liaoxin.ssm.biz.impl;
import com.liaoxin.ssm.biz.ClazzBiz;
import com.liaoxin.ssm.mapper.ClazzMapper;
import com.liaoxin.ssm.model.Clazz;
import com.liaoxin.ssm.util.PageBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
import java.util.Map;
@Service
public class ClazzBizImpl implements ClazzBiz {
@Autowired
private ClazzMapper clazzMapper;
@Override
public int deleteByPrimaryKey(Integer cid) {
return clazzMapper.deleteByPrimaryKey(cid);
}
@Override
public int insert(Clazz record) {
return clazzMapper.insert(record);
}
@Override
public int insertSelective(Clazz record) {
return clazzMapper.insertSelective(record);
}
@Override
public Clazz selectByPrimaryKey(Integer cid) {
return clazzMapper.selectByPrimaryKey(cid);
}
@Override
public int updateByPrimaryKeySelective(Clazz record) {
return clazzMapper.updateByPrimaryKeySelective(record);
}
@Override
public int updateByPrimaryKey(Clazz record) {
return clazzMapper.updateByPrimaryKey(record);
}
@Override
public List<Clazz> listPager(Clazz clazz, PageBean pageBean) {
return clazzMapper.listPager(clazz);
}
@Override
public List<Map> listMapPager(Clazz clazz, PageBean pageBean) {
return clazzMapper.listMapPager(clazz);
}
}
③ClazzMapper.java
package com.liaoxin.ssm.mapper;
import com.liaoxin.ssm.model.Clazz;
import org.springframework.stereotype.Repository;
import java.util.List;
import java.util.Map;
@Repository
public interface ClazzMapper {
int deleteByPrimaryKey(Integer cid);
int insert(Clazz record);
int insertSelective(Clazz record);
Clazz selectByPrimaryKey(Integer cid);
List<Clazz> listPager(Clazz clazz);
List<Map> listMapPager(Clazz clazz);
int updateByPrimaryKeySelective(Clazz record);
int updateByPrimaryKey(Clazz record);
}
④ClazzMapper.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.liaoxin.ssm.mapper.ClazzMapper" >
<resultMap id="BaseResultMap" type="com.liaoxin.ssm.model.Clazz" >
<constructor >
<idArg column="cid" jdbcType="INTEGER" javaType="java.lang.Integer" />
<arg column="cname" jdbcType="VARCHAR" javaType="java.lang.String" />
<arg column="cteacher" jdbcType="VARCHAR" javaType="java.lang.String" />
<arg column="pic" jdbcType="VARCHAR" javaType="java.lang.String" />
</constructor>
</resultMap>
<sql id="Base_Column_List" >
cid, cname, cteacher, pic
</sql>
<select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
select
<include refid="Base_Column_List" />
from t_struts_class
where cid = #{cid,jdbcType=INTEGER}
</select>
<select id="listPager" resultType="com.liaoxin.ssm.model.Clazz" parameterType="com.liaoxin.ssm.model.Clazz" >
select
<include refid="Base_Column_List" />
from t_struts_class
<where>
<if test="cname != null and cname != ''">
and cname like concat('%',#{cname},'%')
</if>
<if test="cid != null and cid != ''">
and cid = #{cid}
</if>
</where>
</select>
<select id="listMapPager" resultType="java.util.Map" parameterType="com.liaoxin.ssm.model.Clazz" >
select
<include refid="Base_Column_List" />
from t_struts_class
<where>
<if test="cname != null and cname != ''">
and cname like concat('%',#{cname},'%')
</if>
<if test="cid != null and cid != ''">
and cid = #{cid}
</if>
</where>
</select>
<delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
delete from t_struts_class
where cid = #{cid,jdbcType=INTEGER}
</delete>
<insert id="insert" parameterType="com.liaoxin.ssm.model.Clazz" >
insert into t_struts_class (cid, cname, cteacher,
pic)
values (#{cid,jdbcType=INTEGER}, #{cname,jdbcType=VARCHAR}, #{cteacher,jdbcType=VARCHAR},
#{pic,jdbcType=VARCHAR})
</insert>
<insert id="insertSelective" parameterType="com.liaoxin.ssm.model.Clazz" >
insert into t_struts_class
<trim prefix="(" suffix=")" suffixOverrides="," >
<if test="cid != null" >
cid,
</if>
<if test="cname != null" >
cname,
</if>
<if test="cteacher != null" >
cteacher,
</if>
<if test="pic != null" >
pic,
</if>
</trim>
<trim prefix="values (" suffix=")" suffixOverrides="," >
<if test="cid != null" >
#{cid,jdbcType=INTEGER},
</if>
<if test="cname != null" >
#{cname,jdbcType=VARCHAR},
</if>
<if test="cteacher != null" >
#{cteacher,jdbcType=VARCHAR},
</if>
<if test="pic != null" >
#{pic,jdbcType=VARCHAR},
</if>
</trim>
</insert>
<update id="updateByPrimaryKeySelective" parameterType="com.liaoxin.ssm.model.Clazz" >
update t_struts_class
<set >
<if test="cname != null" >
cname = #{cname,jdbcType=VARCHAR},
</if>
<if test="cteacher != null" >
cteacher = #{cteacher,jdbcType=VARCHAR},
</if>
<if test="pic != null" >
pic = #{pic,jdbcType=VARCHAR},
</if>
</set>
where cid = #{cid,jdbcType=INTEGER}
</update>
<update id="updateByPrimaryKey" parameterType="com.liaoxin.ssm.model.Clazz" >
update t_struts_class
set cname = #{cname,jdbcType=VARCHAR},
cteacher = #{cteacher,jdbcType=VARCHAR},
pic = #{pic,jdbcType=VARCHAR}
where cid = #{cid,jdbcType=INTEGER}
</update>
</mapper>
⑤JsonController
package com.liaoxin.ssm.web;
import com.liaoxin.ssm.biz.ClazzBiz;
import com.liaoxin.ssm.model.Clazz;
import com.liaoxin.ssm.util.PageBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import javax.servlet.http.HttpServletRequest;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* @author liaoxin
* @create 2022-08-22 16:27
*/
@Controller
@RequestMapping("/clz/json")
public class JsonController {
@Autowired
private ClazzBiz clazzBiz;
@ResponseBody
@RequestMapping("/clzEdit")
public String clzEdit(){
System.out.println("JsonController.list");
return "clzEdit";
}
// list<T>
@ResponseBody
@RequestMapping("/list")
public List<Clazz> list(HttpServletRequest request,Clazz clazz){
// System.out.println("JsonController.list");
PageBean pageBean=new PageBean();
pageBean.setRequest(request);
// [{},{}]
return this.clazzBiz.listPager(clazz,pageBean);
}
// list<Map>
@ResponseBody
@RequestMapping("/listMap")
public List<Map> listMap(HttpServletRequest request, Clazz clazz){
// System.out.println("JsonController.list");
PageBean pageBean=new PageBean();
pageBean.setRequest(request);
// [{},{}]
return
this.clazzBiz.listMapPager(clazz,pageBean);
}
// Map
@ResponseBody
@RequestMapping("/map")
public Map map(HttpServletRequest request, Clazz clazz){
// System.out.println("JsonController.list");
PageBean pageBean=new PageBean();
pageBean.setRequest(request);
// {}
return this.clazzBiz.listMapPager(clazz,pageBean).get(0);
}
// T
@ResponseBody
@RequestMapping("/load")
public Clazz load(HttpServletRequest request, Clazz clazz){
// http://localhost:8080/clz/json/load?cid=2
// System.out.println("JsonController.list");
PageBean pageBean=new PageBean();
pageBean.setRequest(request);
// {}
return this.clazzBiz.listPager(clazz,pageBean).get(0);
}
// {
// msg:"",
// code:200,
// data:[],
// pageBean:{}
// }
@ResponseBody
@RequestMapping("/hunhe")
public Map hunhe(HttpServletRequest request, Clazz clazz){
// http://localhost:8080/clz/json/load?cid=2
PageBean pageBean=new PageBean();
pageBean.setRequest(request);
List<Clazz> lst = this.clazzBiz.listPager(clazz, pageBean);
Map map = new HashMap();
map.put("data",lst);
map.put("pagebean",pageBean);
return map;
// return this.clazzBiz.listPager(clazz,pageBean).get(0);
}
}
4、前台测试
①index.jsp
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2022/8/22
Time: 16:50
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>测试json数据返回</title>
</head>
<body>
<a href="${pageContext.request.contextpath}/clz/json/list">返回List<T>对象</a><hr>
<a href="${pageContext.request.contextpath}/clz/json/listMap">返回List<Map>对象</a><hr>
<a href="${pageContext.request.contextpath}/clz/json/load?cid=1">返回T对象</a><hr>
<a href="${pageContext.request.contextpath}/clz/json/map?cid=1">返回Map对象</a><hr>
<a href="${pageContext.request.contextpath}/clz/json/hunhe">返回混合对象</a><hr>
</body>
</html>
运行效果：
List
List
返回T对象
返回map对象
返回混合对象
二、SpringMVC 的全局异常处理
1、为什么要全局异常处理
我们知道，系统中异常包括：编译时异常和运行时异常RuntimeException，前者通过捕获异常从而获取异常信息，后者主要通过规范代码开发、测试通过手段减少运行时异常的发生。在开发中，不管是dao层、service层还是controller层，都有可能抛出异常，在springmvc中，能将所有类型的异常处理从各处理过程解耦出来，既保证了相关处理过程的功能较单一，也实现了异常信息的统一处理和维护。
2、SpringMVC自带的简单异常处理器
SpringMVC的配置文件
<!-- springmvc提供的简单异常处理器 -->
<bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
<!-- 定义默认的异常处理页面 -->
<property name="defaultErrorView" value="error"/>
<!-- 定义异常处理页面用来获取异常信息的变量名，也可不定义，默认名为exception -->
<property name="exceptionAttribute" value="ex"/>
<!-- 定义需要特殊处理的异常，这是重要点 -->
<property name="exceptionMappings">
<props>
<prop key="java.lang.RuntimeException">error</prop>
</props>
<!-- 还可以定义其他的自定义异常 -->
</property>
</bean>
Error.jsp
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2022/8/22
Time: 17:17
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
${ex}
</body>
</html>
返回List对象
返回List对象
3、通过HandlerExceptionResovler接口实现全局异常
先将上面SpringMVC中关于异常处理的配置取消掉
①GlobalException
package com.liaoxin.ssm.exception;
/**
* @author liaoxin
* @create 2022-08-22 17:20
*/
public class GlobalException extends RuntimeException{
public GlobalException() {
super();
}
public GlobalException(String message) {
super(message);
}
public GlobalException(String message, Throwable cause) {
super(message, cause);
}
public GlobalException(Throwable cause) {
super(cause);
}
protected GlobalException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
super(message, cause, enableSuppression, writableStackTrace);
}
}
②GlobalExceptionHandler
package com.liaoxin.ssm.exception;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* @author liaoxin
* @create 2022-08-22 18:11
*/
@Component
public class GlobalExceptionHandler implements HandlerExceptionResolver {
@Override
public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) {
ModelAndView mv=new ModelAndView();
mv.setViewName("error");
if(e instanceof GlobalException){
GlobalException globalException = (GlobalException) e;
mv.addobject("ex",globalException);
mv.addobject("msg","全局异常");
}else if(e instanceof RuntimeException){
RuntimeException runtimeException = (RuntimeException) e;
mv.addobject("ex",runtimeException.getMessage());
mv.addobject("msg","运行时异常");
}
return mv;
}
}
③controller层
// T
@ResponseBody
@RequestMapping("/load")
public Clazz load(HttpServletRequest request, Clazz clazz){
// http://localhost:8080/clz/json/load?cid=2
// System.out.println("JsonController.list");
// PageBean pageBean=new PageBean();
// pageBean.setRequest(request);
// {}
if(clazz.getCid()!=null){
List<Clazz> lst=this.clazzBiz.listPager(clazz,null);
if(true)
throw new GlobalException("错误出现在JsonController.load");
return lst.get(0);
}
return null;
}
4、使用@ControllerAdvice+@ExceptionHandler实现全局异常
GlobalExceptionResolver：
package com.liaoxin.ssm.exception;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.servlet.ModelAndView;
/**
* @author liaoxin
* @create 2022-08-22 18:40
*/
@ControllerAdvice
public class GlobalExceptionResolver {
@ExceptionHandler
public ModelAndView handler(Exception e){
ModelAndView mv = new ModelAndView();
mv.setViewName("error");
if(e instanceof GlobalException){
GlobalException globalException = (GlobalException) e;
mv.addobject("ex",globalException.getMessage());
mv.addobject("msg","全局异常");
}else if(e instanceof RuntimeException){
RuntimeException runtimeException = (RuntimeException) e;
mv.addobject("ex",runtimeException.getMessage());
mv.addobject("msg","运行时异常..");
}
return mv;
}
}
5、全局异常处理JSON返回
GlobalExceptionjsonResolver：
package com.liaoxin.ssm.exception;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import java.util.HashMap;
import java.util.Map;
/**
* @author liaoxin
* @create 2022-08-22 18:50
*/
@RestControllerAdvice
public class GlobalExceptionjsonResolver {
@ExceptionHandler
public Map handler(Exception e){
Map map = new HashMap();
if(e instanceof GlobalException){
GlobalException globalException = (GlobalException) e;
map.put("ex",globalException.getMessage());
map.put("msg","全局异常");
}else if(e instanceof RuntimeException){
RuntimeException runtimeException = (RuntimeException) e;
map.put("ex",runtimeException.getMessage());
map.put("msg","运行时异常");
}
return map;
}
}
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