• JSON和全局异常处理

    目录

    一、SpringMVC对JSON的支持

     1、pom依赖

    2、Springmvc.xml配置

    3、后台代码

    ①ClazzBiz

    ②ClazzBizImpl

    ③ClazzMapper.java

    ④ClazzMapper.xml

    ⑤JsonController

    4、前台测试

    ①index.jsp

    运行效果：

    二、SpringMVC 的全局异常处理

    1、为什么要全局异常处理

    2、SpringMVC自带的简单异常处理器

    3、通过HandlerExceptionResovler接口实现全局异常

    ①GlobalException

    ②GlobalExceptionHandler

    ③controller层

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

     5、全局异常处理JSON返回

    一、SpringMVC对JSON的支持

     1、pom依赖

    1.  
    2.       <groupId>com.fasterxml.jackson.coregroupId>
    3.       <artifactId>jackson-databindartifactId>
    4.       <version>2.9.3version>
    5.     
    6.     <dependency>
    7.       <groupId>com.fasterxml.jackson.coregroupId>
    8.       <artifactId>jackson-coreartifactId>
    9.       <version>2.9.3version>
    10.     dependency>
    11.     <dependency>
    12.       <groupId>com.fasterxml.jackson.coregroupId>
    13.       <artifactId>jackson-annotationsartifactId>
    14.       <version>2.9.3version>
    15.     dependency>
    16.

    2、Springmvc.xml配置

    1. <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
    2.         <property name="messageConverters">
    3.             <list>
    4.                 <ref bean="mappingJackson2HttpMessageConverter"/>
    5.             list>
    6.         property>
    7.     bean>
    8.     <bean id="mappingJackson2HttpMessageConverter"
    9.           class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
    10.         
    11.         <property name="supportedMediaTypes">
    12.             <list>
    13.                 <value>text/html;charset=UTF-8value>
    14.                 <value>text/json;charset=UTF-8value>
    15.                 <value>application/json;charset=UTF-8value>
    16.             list>
    17.         property>
    18.     bean>
    19.

    3、后台代码

    ①ClazzBiz

    1. package com.liaoxin.ssm.biz;
    2.  
    3. import com.liaoxin.ssm.model.Clazz;
    4. import com.liaoxin.ssm.util.PageBean;
    5.  
    6. import java.util.List;
    7. import java.util.Map;
    8.  
    9. public interface ClazzBiz {
    10.     int deleteByPrimaryKey(Integer cid);
    11.  
    12.     int insert(Clazz record);
    13.  
    14.     int insertSelective(Clazz record);
    15.  
    16.     Clazz selectByPrimaryKey(Integer cid);
    17.  
    18.     int updateByPrimaryKeySelective(Clazz record);
    19.  
    20.     int updateByPrimaryKey(Clazz record);
    21.  
    22.     List listPager(Clazz clazz, PageBean pageBean);
    23.  
    24.     List listMapPager(Clazz clazz, PageBean pageBean);
    25. }

    ②ClazzBizImpl

    1. package com.liaoxin.ssm.biz.impl;
    2.  
    3. import com.liaoxin.ssm.biz.ClazzBiz;
    4. import com.liaoxin.ssm.mapper.ClazzMapper;
    5. import com.liaoxin.ssm.model.Clazz;
    6. import com.liaoxin.ssm.util.PageBean;
    7. import org.springframework.beans.factory.annotation.Autowired;
    8. import org.springframework.stereotype.Service;
    9.  
    10. import java.util.List;
    11. import java.util.Map;
    12.  
    13. @Service
    14. public class ClazzBizImpl implements ClazzBiz {
    15.     @Autowired
    16.     private ClazzMapper clazzMapper;
    17.     @Override
    18.     public int deleteByPrimaryKey(Integer cid) {
    19.         return clazzMapper.deleteByPrimaryKey(cid);
    20.     }
    21.  
    22.     @Override
    23.     public int insert(Clazz record) {
    24.         return clazzMapper.insert(record);
    25.     }
    26.  
    27.     @Override
    28.     public int insertSelective(Clazz record) {
    29.         return clazzMapper.insertSelective(record);
    30.     }
    31.  
    32.     @Override
    33.     public Clazz selectByPrimaryKey(Integer cid) {
    34.         return clazzMapper.selectByPrimaryKey(cid);
    35.     }
    36.  
    37.     @Override
    38.     public int updateByPrimaryKeySelective(Clazz record) {
    39.         return clazzMapper.updateByPrimaryKeySelective(record);
    40.     }
    41.  
    42.     @Override
    43.     public int updateByPrimaryKey(Clazz record) {
    44.         return clazzMapper.updateByPrimaryKey(record);
    45.     }
    46.  
    47.     @Override
    48.     public List listPager(Clazz clazz, PageBean pageBean) {
    49.         return clazzMapper.listPager(clazz);
    50.     }
    51.  
    52.     @Override
    53.     public List listMapPager(Clazz clazz, PageBean pageBean) {
    54.         return clazzMapper.listMapPager(clazz);
    55.     }
    56. }
    57.

    ③ClazzMapper.java

    1. package com.liaoxin.ssm.mapper;
    2.  
    3. import com.liaoxin.ssm.model.Clazz;
    4. import org.springframework.stereotype.Repository;
    5.  
    6. import java.util.List;
    7. import java.util.Map;
    8.  
    9. @Repository
    10. public interface ClazzMapper {
    11.     int deleteByPrimaryKey(Integer cid);
    12.  
    13.     int insert(Clazz record);
    14.  
    15.     int insertSelective(Clazz record);
    16.  
    17.     Clazz selectByPrimaryKey(Integer cid);
    18.  
    19.     List listPager(Clazz clazz);
    20.  
    21.     List listMapPager(Clazz clazz);
    22.  
    23.     int updateByPrimaryKeySelective(Clazz record);
    24.  
    25.     int updateByPrimaryKey(Clazz record);
    26. }

    ④ClazzMapper.xml

    1. "1.0" encoding="UTF-8" ?>
    2. mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
    3. <mapper namespace="com.liaoxin.ssm.mapper.ClazzMapper" >
    4.   <resultMap id="BaseResultMap" type="com.liaoxin.ssm.model.Clazz" >
    5.     <constructor >
    6.       <idArg column="cid" jdbcType="INTEGER" javaType="java.lang.Integer" />
    7.       <arg column="cname" jdbcType="VARCHAR" javaType="java.lang.String" />
    8.       <arg column="cteacher" jdbcType="VARCHAR" javaType="java.lang.String" />
    9.       <arg column="pic" jdbcType="VARCHAR" javaType="java.lang.String" />
    10.     constructor>
    11.   resultMap>
    12.   <sql id="Base_Column_List" >
    13.     cid, cname, cteacher, pic
    14.   sql>
    15.   <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    16.     select
    17.     <include refid="Base_Column_List" />
    18.     from t_struts_class
    19.     where cid = #{cid,jdbcType=INTEGER}
    20.   select>
    21.  
    22.   <select id="listPager" resultType="com.liaoxin.ssm.model.Clazz" parameterType="com.liaoxin.ssm.model.Clazz" >
    23.     select
    24.     <include refid="Base_Column_List" />
    25.     from t_struts_class
    26.     <where>
    27.       <if test="cname != null and cname != ''">
    28.          and cname like concat('%',#{cname},'%')
    29.       if>
    30.       <if test="cid != null and cid != ''">
    31.         and cid = #{cid}
    32.       if>
    33.     where>
    34.   select>
    35.  
    36.   <select id="listMapPager" resultType="java.util.Map" parameterType="com.liaoxin.ssm.model.Clazz" >
    37.     select
    38.     <include refid="Base_Column_List" />
    39.     from t_struts_class
    40.     <where>
    41.       <if test="cname != null and cname != ''">
    42.         and cname like concat('%',#{cname},'%')
    43.       if>
    44.       <if test="cid != null and cid != ''">
    45.         and cid = #{cid}
    46.       if>
    47.     where>
    48.   select>
    49.  
    50.   <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    51.     delete from t_struts_class
    52.     where cid = #{cid,jdbcType=INTEGER}
    53.   delete>
    54.   <insert id="insert" parameterType="com.liaoxin.ssm.model.Clazz" >
    55.     insert into t_struts_class (cid, cname, cteacher, 
    56.       pic)
    57.     values (#{cid,jdbcType=INTEGER}, #{cname,jdbcType=VARCHAR}, #{cteacher,jdbcType=VARCHAR}, 
    58.       #{pic,jdbcType=VARCHAR})
    59.   insert>
    60.   <insert id="insertSelective" parameterType="com.liaoxin.ssm.model.Clazz" >
    61.     insert into t_struts_class
    62.     <trim prefix="(" suffix=")" suffixOverrides="," >
    63.       <if test="cid != null" >
    64.         cid,
    65.       if>
    66.       <if test="cname != null" >
    67.         cname,
    68.       if>
    69.       <if test="cteacher != null" >
    70.         cteacher,
    71.       if>
    72.       <if test="pic != null" >
    73.         pic,
    74.       if>
    75.     trim>
    76.     <trim prefix="values (" suffix=")" suffixOverrides="," >
    77.       <if test="cid != null" >
    78.         #{cid,jdbcType=INTEGER},
    79.       if>
    80.       <if test="cname != null" >
    81.         #{cname,jdbcType=VARCHAR},
    82.       if>
    83.       <if test="cteacher != null" >
    84.         #{cteacher,jdbcType=VARCHAR},
    85.       if>
    86.       <if test="pic != null" >
    87.         #{pic,jdbcType=VARCHAR},
    88.       if>
    89.     trim>
    90.   insert>
    91.   <update id="updateByPrimaryKeySelective" parameterType="com.liaoxin.ssm.model.Clazz" >
    92.     update t_struts_class
    93.     <set >
    94.       <if test="cname != null" >
    95.         cname = #{cname,jdbcType=VARCHAR},
    96.       if>
    97.       <if test="cteacher != null" >
    98.         cteacher = #{cteacher,jdbcType=VARCHAR},
    99.       if>
    100.       <if test="pic != null" >
    101.         pic = #{pic,jdbcType=VARCHAR},
    102.       if>
    103.     set>
    104.     where cid = #{cid,jdbcType=INTEGER}
    105.   update>
    106.   <update id="updateByPrimaryKey" parameterType="com.liaoxin.ssm.model.Clazz" >
    107.     update t_struts_class
    108.     set cname = #{cname,jdbcType=VARCHAR},
    109.       cteacher = #{cteacher,jdbcType=VARCHAR},
    110.       pic = #{pic,jdbcType=VARCHAR}
    111.     where cid = #{cid,jdbcType=INTEGER}
    112.   update>
    113. mapper>

    ⑤JsonController

    1. package com.liaoxin.ssm.web;
    2.  
    3. import com.liaoxin.ssm.biz.ClazzBiz;
    4. import com.liaoxin.ssm.model.Clazz;
    5. import com.liaoxin.ssm.util.PageBean;
    6. import org.springframework.beans.factory.annotation.Autowired;
    7. import org.springframework.stereotype.Controller;
    8. import org.springframework.web.bind.annotation.RequestMapping;
    9. import org.springframework.web.bind.annotation.ResponseBody;
    10.  
    11. import javax.servlet.http.HttpServletRequest;
    12. import java.util.HashMap;
    13. import java.util.List;
    14. import java.util.Map;
    15.  
    16. /**
    17.  * @author liaoxin
    18.  * @create 2022-08-22 16:27
    19.  */
    20. @Controller
    21. @RequestMapping("/clz/json")
    22. public class JsonController {
    23.     @Autowired
    24.     private ClazzBiz clazzBiz;
    25.  
    26.     @ResponseBody
    27.     @RequestMapping("/clzEdit")
    28.     public String clzEdit(){
    29.         System.out.println("JsonController.list");
    30.         return "clzEdit";
    31.     }
    32.  
    33. //    list
    34.     @ResponseBody
    35.     @RequestMapping("/list")
    36.     public List list(HttpServletRequest request,Clazz clazz){
    37. //        System.out.println("JsonController.list");
    38.         PageBean pageBean=new PageBean();
    39.         pageBean.setRequest(request);
    40. //        [{},{}]
    41.         return this.clazzBiz.listPager(clazz,pageBean);
    42.     }
    43.  
    44. //    list
    45.     @ResponseBody
    46.     @RequestMapping("/listMap")
    47.     public List listMap(HttpServletRequest request, Clazz clazz){
    48. //        System.out.println("JsonController.list");
    49.         PageBean pageBean=new PageBean();
    50.         pageBean.setRequest(request);
    51. //        [{},{}]
    52.         return
    53.                 this.clazzBiz.listMapPager(clazz,pageBean);
    54.     }
    55.  
    56. //    Map
    57.     @ResponseBody
    58.     @RequestMapping("/map")
    59.     public Map map(HttpServletRequest request, Clazz clazz){
    60.     //        System.out.println("JsonController.list");
    61.         PageBean pageBean=new PageBean();
    62.         pageBean.setRequest(request);
    63.     //        {}
    64.         return this.clazzBiz.listMapPager(clazz,pageBean).get(0);
    65.     }
    66.  
    67. //    T
    68.     @ResponseBody
    69.     @RequestMapping("/load")
    70.     public Clazz load(HttpServletRequest request, Clazz clazz){
    71. //        http://localhost:8080/clz/json/load?cid=2
    72.         //        System.out.println("JsonController.list");
    73.         PageBean pageBean=new PageBean();
    74.         pageBean.setRequest(request);
    75.         //        {}
    76.         return this.clazzBiz.listPager(clazz,pageBean).get(0);
    77.     }
    78.  
    79. //    {
    80. //         msg:"",
    81. //        code:200,
    82. //        data:[],
    83. //         pageBean:{}
    84. //    }
    85.     @ResponseBody
    86.     @RequestMapping("/hunhe")
    87.     public Map hunhe(HttpServletRequest request, Clazz clazz){
    88.     //        http://localhost:8080/clz/json/load?cid=2
    89.         PageBean pageBean=new PageBean();
    90.         pageBean.setRequest(request);
    91.         List lst = this.clazzBiz.listPager(clazz, pageBean);
    92.         Map map = new HashMap();
    93.         map.put("data",lst);
    94.         map.put("pagebean",pageBean);
    95.         return map;
    96. //        return this.clazzBiz.listPager(clazz,pageBean).get(0);
    97.     }
    98. }
    99.

    4、前台测试

    ①index.jsp

    1. <%--
    2.   Created by IntelliJ IDEA.
    3.   User: Administrator
    4.   Date: 2022/8/22
    5.   Time: 16:50
    6.   To change this template use File | Settings | File Templates.
    7. --%>
    8. <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    11.     测试json数据返回
    14.     返回List<T>对象
    15.     返回List<Map>对象
    16.     返回T对象
    17.     返回Map对象
    18.     返回混合对象
    21.

    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

    2.     <bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
    3.         
    4.         <property name="defaultErrorView" value="error"/>
    5.         
    6.         <property name="exceptionAttribute" value="ex"/>
    7.         
    8.         <property name="exceptionMappings">
    9.             <props>
    10.                 <prop key="java.lang.RuntimeException">errorprop>
    11.             props>
    12.             
    13.         property>
    14.     bean>
    15.

    Error.jsp

    1. <%--
    2.   Created by IntelliJ IDEA.
    3.   User: Administrator
    4.   Date: 2022/8/22
    5.   Time: 17:17
    6.   To change this template use File | Settings | File Templates.
    7. --%>
    8. <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    9. <html>
    10. <head>
    11.     <title>Titletitle>
    12. head>
    13. <body>
    14. ${ex}
    15. body>
    16. html>
    17.

    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

    1. package com.liaoxin.ssm.exception;
    2.  
    3. /**
    4.  * @author liaoxin
    5.  * @create 2022-08-22 17:20
    6.  */
    7. public class GlobalException extends RuntimeException{
    8.  
    9.     public GlobalException() {
    10.         super();
    11.     }
    12.  
    13.     public GlobalException(String message) {
    14.         super(message);
    15.     }
    16.  
    17.     public GlobalException(String message, Throwable cause) {
    18.         super(message, cause);
    19.     }
    20.  
    21.     public GlobalException(Throwable cause) {
    22.         super(cause);
    23.     }
    24.  
    25.     protected GlobalException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
    26.         super(message, cause, enableSuppression, writableStackTrace);
    27.     }
    28. }
    29.

    ②GlobalExceptionHandler

    1. package com.liaoxin.ssm.exception;
    2.  
    3. import org.springframework.stereotype.Component;
    4. import org.springframework.web.servlet.HandlerExceptionResolver;
    5. import org.springframework.web.servlet.ModelAndView;
    6.  
    7. import javax.servlet.http.HttpServletRequest;
    8. import javax.servlet.http.HttpServletResponse;
    9.  
    10. /**
    11.  * @author liaoxin
    12.  * @create 2022-08-22 18:11
    13.  */
    14. @Component
    15. public class GlobalExceptionHandler implements HandlerExceptionResolver {
    16.  
    17.     @Override
    18.     public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) {
    19.         ModelAndView mv=new ModelAndView();
    20.         mv.setViewName("error");
    21.         if(e instanceof GlobalException){
    22.             GlobalException globalException = (GlobalException) e;
    23.             mv.addObject("ex",globalException);
    24.             mv.addObject("msg","全局异常");
    25.         }else if(e instanceof RuntimeException){
    26.             RuntimeException runtimeException = (RuntimeException) e;
    27.             mv.addObject("ex",runtimeException.getMessage());
    28.             mv.addObject("msg","运行时异常");
    29.         }
    30.         return mv;
    31.     }
    32. }
    33.

    ③controller层

    1. //    T
    2.     @ResponseBody
    3.     @RequestMapping("/load")
    4.     public Clazz load(HttpServletRequest request, Clazz clazz){
    5. //        http://localhost:8080/clz/json/load?cid=2
    6.         //        System.out.println("JsonController.list");
    7. //        PageBean pageBean=new PageBean();
    8. //        pageBean.setRequest(request);
    9.         //        {}
    10.         if(clazz.getCid()!=null){
    11.             List lst=this.clazzBiz.listPager(clazz,null);
    12.             if(true)
    13.                 throw new GlobalException("错误出现在JsonController.load");
    14.             return lst.get(0);
    15.         }
    16.         return null;
    17.     }

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

    GlobalExceptionResolver：

    1. package com.liaoxin.ssm.exception;
    2.  
    3. import org.springframework.web.bind.annotation.ControllerAdvice;
    4. import org.springframework.web.bind.annotation.ExceptionHandler;
    5. import org.springframework.web.servlet.ModelAndView;
    6.  
    7. /**
    8.  * @author liaoxin
    9.  * @create 2022-08-22 18:40
    10.  */
    11. @ControllerAdvice
    12. public class GlobalExceptionResolver {
    13.     @ExceptionHandler
    14.     public ModelAndView handler(Exception e){
    15.         ModelAndView mv = new ModelAndView();
    16.         mv.setViewName("error");
    17.         if(e instanceof GlobalException){
    18.             GlobalException globalException = (GlobalException) e;
    19.             mv.addObject("ex",globalException.getMessage());
    20.             mv.addObject("msg","全局异常");
    21.         }else if(e instanceof RuntimeException){
    22.             RuntimeException runtimeException = (RuntimeException) e;
    23.             mv.addObject("ex",runtimeException.getMessage());
    24.             mv.addObject("msg","运行时异常..");
    25.         }
    26.         return mv;
    27.     }
    28. }
    29.

     5、全局异常处理JSON返回

    GlobalExceptionJsonResolver：

    1. package com.liaoxin.ssm.exception;
    2.  
    3. import org.springframework.web.bind.annotation.ExceptionHandler;
    4. import org.springframework.web.bind.annotation.RestControllerAdvice;
    5.  
    6. import java.util.HashMap;
    7. import java.util.Map;
    8.  
    9. /**
    10.  * @author liaoxin
    11.  * @create 2022-08-22 18:50
    12.  */
    13. @RestControllerAdvice
    14. public class GlobalExceptionJsonResolver {
    15.     @ExceptionHandler
    16.     public Map handler(Exception e){
    17.         Map map = new HashMap();
    18.         if(e instanceof GlobalException){
    19.             GlobalException globalException = (GlobalException) e;
    20.             map.put("ex",globalException.getMessage());
    21.             map.put("msg","全局异常");
    22.         }else if(e instanceof RuntimeException){
    23.             RuntimeException runtimeException = (RuntimeException) e;
    24.             map.put("ex",runtimeException.getMessage());
    25.             map.put("msg","运行时异常");
    26.         }
    27.         return map;
    28.     }
    29. }
    30.

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  • 原文地址：https://blog.csdn.net/qq_44247968/article/details/126495268