• SpringMVC之对JSON的支持以及全局异常处理

    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

    2、返回List

    3、返回T

    4、返回Map

    5、返回混合

            2、pom依赖

            导入pom依赖

    1. <dependency>
    2.       <groupId>com.fasterxml.jackson.coregroupId>
    3.       <artifactId>jackson-databindartifactId>
    4.       <version>2.9.3version>
    5.     dependency>
    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>

            3、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>

            4、后台代码

            JsonController

    1. package com.zhw.web;
    2.  
    3. import com.zhw.biz.ClazzBiz;
    4. import com.zhw.model.Clazz;
    5. import com.zhw.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 louis
    18.  * @create  2022-08-22 20:18
    19.  */
    20. @Controller
    21. @RequestMapping("/clz/json")
    22. public class JsonController {
    23.     @Autowired
    24.     private ClazzBiz clazzBiz;
    25.  
    26.     /**
    27.      * 返回List
    28.      * @param req
    29.      * @param clazz
    30.      * @return
    31.      */
    32.     @ResponseBody
    33.     @RequestMapping("/list")
    34.     public List list(HttpServletRequest req, Clazz clazz){
    35.         PageBean pageBean = new PageBean();
    36.         pageBean.setRequest(req);
    37.         List lst = this.clazzBiz.listPager(clazz, pageBean);
    38.         return lst;
    39.     }
    40.  
    41.     /**
    42.      * 返回T
    43.      * @param req
    44.      * @param clazz
    45.      * @return
    46.      */
    47.     @ResponseBody
    48.     @RequestMapping("/load")
    49.     public Clazz load(HttpServletRequest req, Clazz clazz){
    50.         if(clazz.getCid() != null){
    51.             List lst = this.clazzBiz.listPager(clazz, null);
    52.             return lst.get(0);
    53.         }
    54.         return null;
    55.     }
    56.  
    57.  
    58.     /**
    59.      * 返回List
    60.      * @param req
    61.      * @param clazz
    62.      * @return
    63.      */
    64.     @ResponseBody
    65.     @RequestMapping("/mapList")
    66.     public List mapList(HttpServletRequest req, Clazz clazz){
    67.         PageBean pageBean = new PageBean();
    68.         pageBean.setRequest(req);
    69. //        List lst = this.clazzBiz.mapListPager(clazz, pageBean);
    70. //        return lst;
    71.         return null;
    72.     }
    73.  
    74.     /**
    75.      * 返回Map
    76.      * @param req
    77.      * @param clazz
    78.      * @return
    79.      */
    80.     @ResponseBody
    81.     @RequestMapping("/mapLoad")
    82.     public Map mapLoad(HttpServletRequest req, Clazz clazz){
    83.         if(clazz.getCid() != null){
    84.             List lst = this.clazzBiz.mapListPager(clazz, null);
    85.             return lst.get(0);
    86.         }
    87.         return null;
    88.     }
    89.  
    90.  
    91.     @ResponseBody
    92.     @RequestMapping("/all")
    93.     public Map all(HttpServletRequest req, Clazz clazz){
    94.         PageBean pageBean = new PageBean();
    95.         pageBean.setRequest(req);
    96.         List lst = this.clazzBiz.listPager(clazz, pageBean);
    97.         Map map = new HashMap();
    98.         map.put("lst",lst);
    99.         map.put("pageBean",pageBean);
    100.         return map;
    101.     }
    102.  
    103.     @ResponseBody
    104.     @RequestMapping("/jsonStr")
    105.     public String jsonStr(HttpServletRequest req, Clazz clazz){
    106.         return "clzEdit";
    107.     }
    108.  
    109.  
    110. }

            mapper.xml

    1. <select id="mapListPager" parameterType="com.zhw.model.Clazz" resultType="java.util.Map">
    2.         select
    3.         <include refid="Base_Column_List" />
    4.         from t_struts_class
    5.         <where>
    6.             <if test="cname != null and cname != ''">
    7.                 cname like CONCAT('%',#{cname},'%')
    8.             if>
    9.             <if test="cid != null and cid != ''">
    10.                 cid = #{cid}
    11.             if>
    12.         where>
    13.     select>

            5、前台代码

    1. <body>
    2. <h3>JSONh3>
    3. <a href="${pageContext.request.contextPath}/clz/json/list">返回List<T>a><hr>
    4. <a href="${pageContext.request.contextPath}/clz/json/mapList">返回List<Map>a><hr>
    5. <a href="${pageContext.request.contextPath}/clz/json/load?cid=1">返回Ta><hr>
    6. <a href="${pageContext.request.contextPath}/clz/json/mapLoad?cid=1">返回Mapa><hr>
    7. <a href="${pageContext.request.contextPath}/clz/json/all">返回混合a><hr>
    8. <a href="${pageContext.request.contextPath}/clz/json/jsonStr">返回JSON字符串a><hr>
    9. 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

    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.

                    2、后台代码

    ClazzBizImpl

    1.  @Override
    2.     public List mapListPager(Clazz clazz, PageBean pageBean) {
    3.         if (true)
    4.             throw new RuntimeException("错误出现在 ClazzBizImpl.mapListPager...");
    5.         return clazzMapper.mapListPager(clazz);
    6.     }
    7.

    Controller

    1.  @ResponseBody
    2.     @RequestMapping("/list")
    3.     public List list(HttpServletRequest req, Clazz clazz){
    4.         PageBean pageBean = new PageBean();
    5.         pageBean.setRequest(req);
    6.         if (true)
    7.             throw new RuntimeException("错误出现在 JsonController.list...");
    8.         List lst = this.clazzBiz.listPager(clazz, pageBean);
    9.         return lst;
    10.     }

     

    1. <%--
    2.   Created by IntelliJ IDEA.
    3.   User: Administrator
    4.   Date: 2022/8/22
    5.   Time: 20:32
    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.

            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

    1. package com.zhw.exception;
    2.  
    3. /**
    4.  * @author louis
    5.  * @create  2022-08-22 20:47
    6.  */
    7. public class GlobalException extends RuntimeException{
    8.     public GlobalException() {
    9.         super();
    10.     }
    11.  
    12.     public GlobalException(String message) {
    13.         super(message);
    14.     }
    15.  
    16.     public GlobalException(String message, Throwable cause) {
    17.         super(message, cause);
    18.     }
    19.  
    20.     public GlobalException(Throwable cause) {
    21.         super(cause);
    22.     }
    23.  
    24.     protected GlobalException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
    25.         super(message, cause, enableSuppression, writableStackTrace);
    26.     }
    27. }

                    2、GlobalExceptionHandler 

    1. package com.zhw.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 louis
    12.  * @create  2022-08-22 20:49
    13.  */
    14. @Component
    15. public class GlobalExceptionHandler implements HandlerExceptionResolver {
    16.     @Override
    17.     public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) {
    18.         ModelAndView mv=new ModelAndView();
    19.         mv.setViewName("error");
    20.         if(e instanceof GlobalException){
    21.             GlobalException globalException = (GlobalException) e;
    22.             mv.addObject("ex",globalException);
    23.             mv.addObject("msg","全局异常。。。");
    24.         }else if(e instanceof RuntimeException){
    25.             RuntimeException runtimeException = (RuntimeException) e;
    26.             mv.addObject("ex",runtimeException.getMessage());
    27.             mv.addObject("msg","运行时异常。。。");
    28.         }
    29.         return mv;
    30.     }
    31. }

            3、controller

    1.  @ResponseBody
    2.     @RequestMapping("/load")
    3.     public Clazz load(HttpServletRequest req, Clazz clazz){
    4.         if(clazz.getCid() != null){
    5.             List lst = this.clazzBiz.listPager(clazz, null);
    6.             return lst.get(0);
    7.         }
    8.         return null;
    9.     }

             4、效果

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

            

    1. package com.zhw.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 louis
    9.  * @create  2022-08-22 20:59
    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. }

            4、全局异常处理JSON返回

    1. package com.zhw.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 louis
    11.  * @create  2022-08-22 21:02
    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. }

     

     

             

     

  • 相关阅读:
    说说UE5中的几种字符串类
    Linux笔记
    Vue 指令、计算属性、侦听器
    MySQL 高级(进阶) SQL 语句 (一)
    【BP-Adaboost预测】基于BP神经网络的Adaboost的单维时间序列预测研究（Matlab代码实现）
    Kafka系列之高频面试题
    我为什么要学习openCV，什么是openCV
    centos7系统下，实现1台服务器免密登录多台服务器功能
    YOLO学习
    JS【filter过滤器】的用法
  • 原文地址：https://blog.csdn.net/qq_62331938/article/details/126497043