JSON和全局异常处理

一、SpringMVC对JSON的支持

1、JOSN的各种场景

1.1返回List
1.2返回List
1.3返回T
1.4返回Map
1.5返回混合
1.6返回JSON字符串

2、pom依赖

 <dependency>
      <groupId>com.fasterxml.jackson.coregroupId>
      <artifactId>jackson-databindartifactId>
      <version>2.9.3version>
    dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.coregroupId>
      <artifactId>jackson-coreartifactId>
      <version>2.9.3version>
    dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.coregroupId>
      <artifactId>jackson-annotationsartifactId>
      <version>2.9.3version>
    dependency>

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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">
        
        <property name="supportedMediaTypes">
            <list>
                <value>text/html;charset=UTF-8value>
                <value>text/json;charset=UTF-8value>
                <value>application/json;charset=UTF-8value>
            list>
        property>
    bean>

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4、后台代码

①ClazzBiz

package com.xnx.ssm.biz;

import com.xnx.ssm.model.Clazz;
import com.xnx.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);
}
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②ClazzBizImpl

package com.xnx.ssm.biz.impl;

import com.xnx.ssm.biz.ClazzBiz;
import com.xnx.ssm.mapper.ClazzMapper;
import com.xnx.ssm.model.Clazz;
import com.xnx.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);
    }
}

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③ClazzMapper.java

package com.xnx.ssm.mapper;

import com.xnx.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);
}
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④ClazzMapper.xml


DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.xnx.ssm.mapper.ClazzMapper" >
  <resultMap id="BaseResultMap" type="com.xnx.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.xnx.ssm.model.Clazz" parameterType="com.xnx.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.xnx.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.xnx.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.xnx.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.xnx.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.xnx.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>
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⑤JsonController

package com.xnx.ssm.web;

import com.xnx.ssm.biz.ClazzBiz;
import com.xnx.ssm.model.Clazz;
import com.xnx.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 xnx
 * @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
    @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
    @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);
    }
}

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5、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="${pageContext.request.contextPath}/clz/json/list">返回List&lt;T&gt;对象</a><hr>
    <a href="${pageContext.request.contextPath}/clz/json/listMap">返回List&lt;Map&gt;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>

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运行效果：

在这里插入图片描述
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、SpringMVC自带的简单异常处理器

SpringMVC的配置文件


    <bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
        
        <property name="defaultErrorView" value="error"/>
        
        <property name="exceptionAttribute" value="ex"/>
        
        <property name="exceptionMappings">
            <props>
                <prop key="java.lang.RuntimeException">errorprop>
            props>
            
        property>
    bean>

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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>

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返回List对象
在这里插入图片描述
返回List对象

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

①GlobalException

package com.xnx.ssm.exception;

/**
 * @author xnx
 * @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);
    }
}

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②GlobalExceptionHandler

package com.xnx.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 xnx
 * @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;
    }
}

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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;
    }
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在这里插入图片描述

3、使用@ControllerAdvice+@ExceptionHandler实现全局异常

GlobalExceptionResolver：

package com.xnx.ssm.exception;

import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.servlet.ModelAndView;

/**
 * @author xnx
 * @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;
    }
}

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4、全局异常处理JSON返回

GlobalExceptionJsonResolver：

package com.xnx.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 xnx
 * @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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点击返回T对象：
在这里插入图片描述

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原文地址：https://blog.csdn.net/weixin_67677668/article/details/126469526

JSON和全局异常处理

目录

一、SpringMVC对JSON的支持

1、JOSN的各种场景

2、pom依赖

3、Springmvc.xml配置

4、后台代码

①ClazzBiz

②ClazzBizImpl

③ClazzMapper.java

④ClazzMapper.xml

⑤JsonController

5、前台测试

①index.jsp

运行效果：

二、SpringMVC 的全局异常处理

1、SpringMVC自带的简单异常处理器

2、通过HandlerExceptionResovler接口实现全局异常

①GlobalException

②GlobalExceptionHandler

③controller层

3、使用@ControllerAdvice+@ExceptionHandler实现全局异常

4、全局异常处理JSON返回