前言
上一次分享了JSR303 以及 拦截器。 本次分享的内容为，JSON 以及全局异常的处理
一、SpringMVC对JSON的支持
1、JSON的各种场景
1、返回List<T>
2、返回List<Map>
3、返回T
4、返回Map
5、返回混合
2、pom依赖
导入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>3、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>JsonController
package com.zhw.web;
import com.zhw.biz.ClazzBiz;
import com.zhw.model.Clazz;
import com.zhw.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 louis
* @create 2022-08-22 20:18
*/
@Controller
@RequestMapping("/clz/json")
public class JsonController {
@Autowired
private ClazzBiz clazzBiz;
/**
* 返回List<T>
* @param req
* @param clazz
* @return
*/
@ResponseBody
@RequestMapping("/list")
public List<Clazz> list(HttpServletRequest req, Clazz clazz){
PageBean pageBean = new PageBean();
pageBean.setRequest(req);
List<Clazz> lst = this.clazzBiz.listPager(clazz, pageBean);
return lst;
}
/**
* 返回T
* @param req
* @param clazz
* @return
*/
@ResponseBody
@RequestMapping("/load")
public Clazz load(HttpServletRequest req, Clazz clazz){
if(clazz.getCid() != null){
List<Clazz> lst = this.clazzBiz.listPager(clazz, null);
return lst.get(0);
}
return null;
}
/**
* 返回List<Map>
* @param req
* @param clazz
* @return
*/
@ResponseBody
@RequestMapping("/mapList")
public List<Map> mapList(HttpServletRequest req, Clazz clazz){
PageBean pageBean = new PageBean();
pageBean.setRequest(req);
// List<Map> lst = this.clazzBiz.mapListPager(clazz, pageBean);
// return lst;
return null;
}
/**
* 返回Map
* @param req
* @param clazz
* @return
*/
@ResponseBody
@RequestMapping("/mapLoad")
public Map mapLoad(HttpServletRequest req, Clazz clazz){
if(clazz.getCid() != null){
List<Map> lst = this.clazzBiz.mapListPager(clazz, null);
return lst.get(0);
}
return null;
}
@ResponseBody
@RequestMapping("/all")
public Map all(HttpServletRequest req, Clazz clazz){
PageBean pageBean = new PageBean();
pageBean.setRequest(req);
List<Clazz> lst = this.clazzBiz.listPager(clazz, pageBean);
Map map = new HashMap();
map.put("lst",lst);
map.put("pageBean",pageBean);
return map;
}
@ResponseBody
@RequestMapping("/jsonStr")
public String jsonStr(HttpServletRequest req, Clazz clazz){
return "clzEdit";
}
}
mapper.xml
<select id="mapListPager" parameterType="com.zhw.model.Clazz" resultType="java.util.Map">
select
<include refid="Base_Column_List" />
from t_struts_class
<where>
<if test="cname != null and cname != ''">
cname like CONCAT('%',#{cname},'%')
</if>
<if test="cid != null and cid != ''">
cid = #{cid}
</if>
</where>
</select><body>
<h3>JSON</h3>
<a href="${pageContext.request.contextpath}/clz/json/list">返回List<T></a><hr>
<a href="${pageContext.request.contextpath}/clz/json/mapList">返回List<Map></a><hr>
<a href="${pageContext.request.contextpath}/clz/json/load?cid=1">返回T</a><hr>
<a href="${pageContext.request.contextpath}/clz/json/mapLoad?cid=1">返回Map</a><hr>
<a href="${pageContext.request.contextpath}/clz/json/all">返回混合</a><hr>
<a href="${pageContext.request.contextpath}/clz/json/jsonStr">返回JSON字符串</a><hr>
</body>6、效果展示
二、全局异常处理
1、SpringMVC自带的简单异常处理
1、Springmvc.xml配置
<!-- 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>
ClazzBizImpl
@Override
public List<Map> mapListPager(Clazz clazz, PageBean pageBean) {
if (true)
throw new RuntimeException("错误出现在 ClazzBizImpl.mapListPager...");
return clazzMapper.mapListPager(clazz);
}
Controller
@ResponseBody
@RequestMapping("/list")
public List<Clazz> list(HttpServletRequest req, Clazz clazz){
PageBean pageBean = new PageBean();
pageBean.setRequest(req);
if (true)
throw new RuntimeException("错误出现在 JsonController.list...");
List<Clazz> lst = this.clazzBiz.listPager(clazz, pageBean);
return lst;
}
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2022/8/22
Time: 20:32
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>
3、效果演示
2、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
1、GlobalException
package com.zhw.exception;
/**
* @author louis
* @create 2022-08-22 20:47
*/
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);
}
}
2、GlobalExceptionHandler
package com.zhw.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 louis
* @create 2022-08-22 20:49
*/
@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;
}
}
3、controller
@ResponseBody
@RequestMapping("/load")
public Clazz load(HttpServletRequest req, Clazz clazz){
if(clazz.getCid() != null){
List<Clazz> lst = this.clazzBiz.listPager(clazz, null);
return lst.get(0);
}
return null;
}4、效果
3、使用@ControllerAdvice+@ExceptionHandler实现全局异常
package com.zhw.exception;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.servlet.ModelAndView;
/**
* @author louis
* @create 2022-08-22 20:59
*/
@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;
}
}
4、全局异常处理JSON返回
package com.zhw.exception;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import java.util.HashMap;
import java.util.Map;
/**
* @author louis
* @create 2022-08-22 21:02
*/
@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;
}
}
原文地址：https://www.jb51.cc/wenti/3286287.html
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