SpringMVC之JSON返回&异常处理机制

bing人2023-09-21 20:25

一.什么是SpringMVC之JSON返回&异常处理机制

二.Json处理

导入pom.xml依赖

导入Spring-Mvc.xml

编写JsonController

编写Sql语句

测试结果

json转换的注解

测试结果（@JsonIgnore）

三.全局异常处理机制

为什么要全局异常处理

异常处理思路

​编辑

自写一个错误代码

[​编辑 输出结果](#编辑 输出结果)

异常处理方式（一）

新建一个erreo.jsp

输出结果

异常处理（二）

编写GlobalException类

编写全局异常处理类GlobalExceptionHandler

在error.jsp中编写

在JsonController类编写异常

测试结果

[​编辑 异常处理（三）](#编辑 异常处理（三）)

编写GlobalExceptionResolver类

测试结果

重新编写GlobalExceptionResolver类

测试结果

一.什么是SpringMVC之JSON返回&异常处理机制

SpringMVC是一个Web框架，它提供了许多方便的特性，其中之一就是JSON返回和异常处理机制。

JSON返回指的是，当客户端向服务器发起请求时，服务器可以返回JSON格式的响应数据。这是非常常见的一种情况，特别是在前后端分离的开发模式中，后端通常会返回JSON格式的数据。

SpringMVC提供了多种方式来实现JSON返回，其中最简单的方式是使用@ResponseBody注解，这个注解可以将Controller方法返回的对象自动转换成JSON格式的数据，然后响应给客户端。如果需要更加灵活的JSON格式化方式，可以使用Jackson或者FastJSON等库进行定制化配置。

异常处理机制指的是当服务器出现异常时，SpringMVC提供了一套通用的异常处理机制，可以统一处理异常，返回友好的错误信息给客户端。在SpringMVC中，异常处理主要分为两种方式，一种是基于@ControllerAdvice注解的全局异常处理方式，另一种是基于@ExceptionHandler注解的局部异常处理方式。通过这两种方式，我们可以针对不同的异常类型进行不同的处理，比如返回特定的错误码、错误信息等。这样可以提高系统的容错性和可靠性。

二.Json处理

导入pom.xml依赖
java 复制代码 
<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.example</groupId>
  <artifactId>xyzy</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>xyzy Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <maven.compiler.plugin.version>3.7.0</maven.compiler.plugin.version>

    <!--添加jar包依赖-->
    <!--1.spring 5.0.2.RELEASE相关-->
    <spring.version>5.0.2.RELEASE</spring.version>
    <!--2.mybatis相关-->
    <mybatis.version>3.4.5</mybatis.version>
    <!--mysql-->
    <mysql.version>5.1.44</mysql.version>
    <!--pagehelper分页jar依赖-->
    <pagehelper.version>5.1.2</pagehelper.version>
    <!--mybatis与spring集成jar依赖-->
    <mybatis.spring.version>1.3.1</mybatis.spring.version>
    <!--3.dbcp2连接池相关 druid-->
    <commons.dbcp2.version>2.1.1</commons.dbcp2.version>
    <commons.pool2.version>2.4.3</commons.pool2.version>
    <!--4.log日志相关-->
    <log4j2.version>2.9.1</log4j2.version>
    <log4j2.disruptor.version>3.2.0</log4j2.disruptor.version>
    <slf4j.version>1.7.13</slf4j.version>
    <!--5.其他-->
    <junit.version>4.12</junit.version>
    <servlet.version>4.0.0</servlet.version>
    <lombok.version>1.18.2</lombok.version>

    <mybatis.ehcache.version>1.1.0</mybatis.ehcache.version>
    <ehcache.version>2.10.0</ehcache.version>

    <redis.version>2.9.0</redis.version>
    <redis.spring.version>1.7.1.RELEASE</redis.spring.version>
    <jackson.version>2.9.3</jackson.version>
    <jstl.version>1.2</jstl.version>
    <standard.version>1.1.2</standard.version>
    <tomcat-jsp-api.version>8.0.47</tomcat-jsp-api.version>
    <commons-fileupload.version>1.3.3</commons-fileupload.version>
    <hibernate-validator.version>5.0.2.Final</hibernate-validator.version>

    <shiro.version>1.3.2</shiro.version>
  </properties>

  <dependencies>
    <!--1.spring相关-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-beans</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-orm</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aspects</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>${spring.version}</version>
    </dependency>


    <!--2.mybatis相关-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>${mybatis.version}</version>
    </dependency>
    <!--mysql-->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>${mysql.version}</version>
    </dependency>
    <!--pagehelper分页插件jar包依赖-->
    <dependency>
      <groupId>com.github.pagehelper</groupId>
      <artifactId>pagehelper</artifactId>
      <version>${pagehelper.version}</version>
    </dependency>
    <!--mybatis与spring集成jar包依赖-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>${mybatis.spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context-support</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <!--mybatis与ehcache整合-->
    <dependency>
      <groupId>org.mybatis.caches</groupId>
      <artifactId>mybatis-ehcache</artifactId>
      <version>${mybatis.ehcache.version}</version>
    </dependency>
    <!--ehcache依赖-->
    <dependency>
      <groupId>net.sf.ehcache</groupId>
      <artifactId>ehcache</artifactId>
      <version>${ehcache.version}</version>
    </dependency>

    <dependency>
      <groupId>redis.clients</groupId>
      <artifactId>jedis</artifactId>
      <version>${redis.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework.data</groupId>
      <artifactId>spring-data-redis</artifactId>
      <version>${redis.spring.version}</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>${jackson.version}</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>${jackson.version}</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-annotations</artifactId>
      <version>${jackson.version}</version>
    </dependency>

    <!--3.dbcp2连接池相关-->
    <dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-dbcp2</artifactId>
      <version>${commons.dbcp2.version}</version>
      <exclusions>
        <exclusion>
          <artifactId>commons-pool2</artifactId>
          <groupId>org.apache.commons</groupId>
        </exclusion>
      </exclusions>
    </dependency>
    <dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-pool2</artifactId>
      <version>${commons.pool2.version}</version>
    </dependency>

    <!--springmvc依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <!--4.log日志相关依赖-->

    <!-- log4j2日志相关依赖 -->
    <!-- log配置：Log4j2 + Slf4j -->
    <!-- slf4j核心包-->
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>${slf4j.version}</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>jcl-over-slf4j</artifactId>
      <version>${slf4j.version}</version>
      <scope>runtime</scope>
    </dependency>

    <!--核心log4j2jar包-->
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-api</artifactId>
      <version>${log4j2.version}</version>
    </dependency>
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-core</artifactId>
      <version>${log4j2.version}</version>
    </dependency>
    <!--用于与slf4j保持桥接-->
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-slf4j-impl</artifactId>
      <version>${log4j2.version}</version>
    </dependency>
    <!--web工程需要包含log4j-web，非web工程不需要-->
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-web</artifactId>
      <version>${log4j2.version}</version>
      <scope>runtime</scope>
    </dependency>

    <!--需要使用log4j2的AsyncLogger需要包含disruptor-->
    <dependency>
      <groupId>com.lmax</groupId>
      <artifactId>disruptor</artifactId>
      <version>${log4j2.disruptor.version}</version>
    </dependency>

    <!--5.其他-->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>${junit.version}</version>
<!--      <scope>test</scope>-->
    </dependency>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>${servlet.version}</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>${lombok.version}</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>jstl</groupId>
      <artifactId>jstl</artifactId>
      <version>${jstl.version}</version>
    </dependency>
    <dependency>
      <groupId>taglibs</groupId>
      <artifactId>standard</artifactId>
      <version>${standard.version}</version>
    </dependency>
    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat-jsp-api</artifactId>
      <version>${tomcat-jsp-api.version}</version>
    </dependency>
    <dependency>
      <groupId>commons-fileupload</groupId>
      <artifactId>commons-fileupload</artifactId>
      <version>${commons-fileupload.version}</version>
    </dependency>

    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-validator</artifactId>
      <version>${hibernate-validator.version}</version>
    </dependency>

    <!--shiro依赖-->
    <dependency>
      <groupId>org.apache.shiro</groupId>
      <artifactId>shiro-core</artifactId>
      <version>${shiro.version}</version>
    </dependency>
    <dependency>
      <groupId>org.apache.shiro</groupId>
      <artifactId>shiro-web</artifactId>
      <version>${shiro.version}</version>
    </dependency>
    <dependency>
      <groupId>org.apache.shiro</groupId>
      <artifactId>shiro-spring</artifactId>
      <version>${shiro.version}</version>
    </dependency>
  </dependencies>

  <build>
    <finalName>xyzy</finalName>


    <resources>
      <!--解决mybatis-generator-maven-plugin运行时没有将XxxMapper.xml文件放入target文件夹的问题-->
      <resource>
        <directory>src/main/java</directory>
        <includes>
          <include>**/*.xml</include>
        </includes>
      </resource>
      <!--解决mybatis-generator-maven-plugin运行时没有将jdbc.properites文件放入target文件夹的问题-->
      <resource>
        <directory>src/main/resources</directory>
        <includes>
          <include>*.properties</include>
          <include>*.xml</include>
        </includes>
      </resource>
    </resources>


      <plugins>

        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>${maven.compiler.plugin.version}</version>
          <configuration>
            <source>${maven.compiler.source}</source>
            <target>${maven.compiler.target}</target>
            <encoding>${project.build.sourceEncoding}</encoding>
          </configuration>
        </plugin>
        <plugin>
          <groupId>org.mybatis.generator</groupId>
          <artifactId>mybatis-generator-maven-plugin</artifactId>
          <version>1.3.2</version>
          <dependencies>
            <!--使用Mybatis-generator插件不能使用太高版本的mysql驱动 -->
            <dependency>
              <groupId>mysql</groupId>
              <artifactId>mysql-connector-java</artifactId>
              <version>${mysql.version}</version>
            </dependency>
          </dependencies>
          <configuration>
            <overwrite>true</overwrite>
          </configuration>
        </plugin>


        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
  </build>
</project>
导入Spring-Mvc.xml
java 复制代码 
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
      http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
      http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
      http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">
    <!--1) 扫描com.zking.zf及子子孙孙包下的控制器(扫描范围过大，耗时)-->
    <context:component-scan base-package="com.xy"/>

    <!--2) 此标签默认注册DefaultAnnotationHandlerMapping和AnnotationMethodHandlerAdapter -->
    <mvc:annotation-driven />

    <!--3) 创建ViewResolver视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!-- viewClass需要在pom中引入两个包：standard.jar and jstl.jar -->
        <property name="viewClass"
                  value="org.springframework.web.servlet.view.JstlView"></property>
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>



    <!--4) 单独处理图片、样式、js等资源 -->
<!--    <mvc:resources location="/css/" mapping="/css/**"/>-->
<!--     <mvc:resources location="/js/" mapping="/js/**"/>-->
<!--     <mvc:resources location="WEB-INF/images/" mapping="/images/**"/>-->
    <mvc:resources location="/static/" mapping="/static/**"/>

    <!--处理文件的上传下载-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <!-- 必须和用户JSP 的pageEncoding属性一致，以便正确解析表单的内容 -->
        <property name="defaultEncoding" value="UTF-8"></property>
        <!-- 文件最大大小(字节) 1024*1024*50=50M-->
        <property name="maxUploadSize" value="52428800"></property>
        <!--resolveLazily属性启用是为了推迟文件解析，以便捕获文件大小异常-->
        <property name="resolveLazily" value="true"/>
    </bean>

    <!--配置拦截器-->
    <mvc:interceptors>
      <bean class="com.xy.interceptor.LoginInterceptor"></bean>

    </mvc:interceptors>

        <!--2) 多拦截器（拦截器链）-->
    <!--<mvc:interceptors>-->
        <!--<mvc:interceptor>
            <mvc:mapping path="/**"/>
            <bean class="com.xy.interceptor.OneInterceptor"/>
        </mvc:interceptor>
        <mvc:interceptor>
            <mvc:mapping path="/hpjy/**"/>
            <bean class="com.xy.interceptor.TwoInterceptor"/>
        </mvc:interceptor>
    </mvc:interceptors>-->
    <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>
    <!--处理controller层发送请求到biz,会经过切面的拦截处理-->
    <aop:aspectj-autoproxy/>
</beans>
编写JsonController
java 复制代码 
package com.xy.web;

import com.xy.biz.hpjyBiz;
import com.xy.biz.hpjyBiz;
import com.xy.model.hpjy;
import com.xy.utils.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 org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletRequest;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author小李飞刀
 * @site www.javaxl.com
 * @company xxx公司
 * @create  2022-08-17 9:41
 */
//@ResponseBody
//@Controller
   @RestController
@RequestMapping("/hpjy/json")
public class JsonController {
    @Autowired
    private hpjyBiz hpjyBiz;

    /**
     * 返回List<T>
     * @param req
     * @param hpjy
     * @return
     */
//    @ResponseBody
    @RequestMapping("/list")
    public List<hpjy> list(HttpServletRequest req, hpjy hpjy){
        PageBean pageBean = new PageBean();
        pageBean.setRequest(req);
        List<hpjy> lst = this.hpjyBiz.listPager(hpjy, pageBean);
        return lst;
    }

    /**
     * 返回T
     * @param req
     * @param hpjy
     * @return
     */
//    @ResponseBody
    @RequestMapping("/load")
    public hpjy load(HttpServletRequest req, hpjy hpjy){
        if(hpjy.getId() != null){
            List<hpjy> lst = this.hpjyBiz.listPager(hpjy, null);
            return lst.get(0);
        }
        return null;
    }


    /**
     * 返回List<Map>
     * @param req
     * @param hpjy
     * @return
     */
//    @ResponseBody
    @RequestMapping("/mapList")
    public List<Map> mapList(HttpServletRequest req, hpjy hpjy){
        PageBean pageBean = new PageBean();
        pageBean.setRequest(req);
        List<Map> lst = this.hpjyBiz.mapListPager(hpjy, pageBean);
        return lst;
    }

    /**
     * 返回Map
     * @param req
     * @param hpjy
     * @return
     */
//    @ResponseBody
    @RequestMapping("/mapLoad")
    public Map mapLoad(HttpServletRequest req, hpjy hpjy){
        if(hpjy.getId() != null){
            List<Map> lst = this.hpjyBiz.mapListPager(hpjy, null);
            return lst.get(0);
        }
        return null;
    }


//    @ResponseBody
    @RequestMapping("/all")
    public Map all(HttpServletRequest req, hpjy hpjy){
        PageBean pageBean = new PageBean();
        pageBean.setRequest(req);
        List<hpjy> lst = this.hpjyBiz.listPager(hpjy, pageBean);
        Map map = new HashMap();
        map.put("lst",lst);
        map.put("pageBean",pageBean);
        return map;
    }

//    @ResponseBody
    @RequestMapping("/jsonStr")
    public String jsonStr(HttpServletRequest req, hpjy hpjy){
        return "hpjyEdit";
    }


}
编写Sql语句
测试结果
复制代码 
//    @ResponseBody
    @RequestMapping("/load")
    public hpjy load(HttpServletRequest req, hpjy hpjy){
        if(hpjy.getId() != null){
            List<hpjy> lst = this.hpjyBiz.listPager(hpjy, null);
            return lst.get(0);
        }
        return null;
    }
测试结果如下：
复制代码 
  /**
     * 返回List<Map>
     * @param req
     * @param hpjy
     * @return
     */
//    @ResponseBody
    @RequestMapping("/mapList")
    public List<Map> mapList(HttpServletRequest req, hpjy hpjy){
        PageBean pageBean = new PageBean();
        pageBean.setRequest(req);
        List<Map> lst = hpjyBiz.mapListPager(hpjy, pageBean);
        return lst;
    }

测试结果如下：

复制代码 
 /**
     * 返回Map
     * @param req
     * @param hpjy
     * @return
     */
//    @ResponseBody
    @RequestMapping("/mapLoad")
    public Map mapLoad(HttpServletRequest req, hpjy hpjy){
        if(hpjy.getId() != null){
            List<Map> lst = this.hpjyBiz.mapListPager(hpjy, null);
            return lst.get(0);
        }
        return null;
    }

测试结果如下：

复制代码 
//    @ResponseBody
    @RequestMapping("/all")
    public Map all(HttpServletRequest req, hpjy hpjy){
        PageBean pageBean = new PageBean();
        pageBean.setRequest(req);
        List<hpjy> lst = this.hpjyBiz.listPager(hpjy, pageBean);
        Map map = new HashMap();
        map.put("lst",lst);
        map.put("pageBean",pageBean);
        return map;
    }

测试结果如下：

复制代码 
//    @ResponseBody
    @RequestMapping("/jsonStr")
    public String jsonStr(HttpServletRequest req, hpjy hpjy){
        return "hpjyEdit";
    }
测试结果如下：
json转换的注解
测试结果（@JsonIgnore）

(注：隐藏想要隐藏的)

三.全局异常处理机制

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。

异常处理思路
自写一个错误代码
输出结果
异常处理方式（一）

在Spring-Mvc.xml中写异常处理方式

新建一个erreo.jsp

(注：获取异常的xx)

输出结果
异常处理（二）
编写GlobalException类
java 复制代码 
package com.xy.exception;

public class GlobalException extends RuntimeException {
    public GlobalException() {
    }

    public GlobalException(String message) {
        super(message);
    }

    public GlobalException(String message, Throwable cause) {
        super(message, cause);
    }

    public GlobalException(Throwable cause) {
        super(cause);
    }

    public GlobalException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
        super(message, cause, enableSuppression, writableStackTrace);
    }
}
编写全局异常处理类GlobalExceptionHandler
java 复制代码 
package com.xy.component;

import com.xy.exception.GlobalException;
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;
//全局异常处理类
@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.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....");
        }else {
            mv.addObject("ex",e.getMessage());
            mv.addObject("msg","其他异常....");
        }

        return mv;
    }
}
在error.jsp中编写
在JsonController类编写异常
测试结果
异常处理（三）
编写GlobalExceptionResolver类
java 复制代码 
package com.xy.component;

import com.xy.exception.GlobalException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;

import java.util.HashMap;
import java.util.Map;

@ControllerAdvice
public class GlobalExceptionResolver {

// 返回错误json数据
    @ResponseBody
    @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....");
        }else {
            map.put("ex",e.getMessage());
            map.put("msg","其它异常....");
        }
        return map;
    }
测试结果
重新编写GlobalExceptionResolver类
java 复制代码 
package com.xy.component;

import com.xy.exception.GlobalException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;

import java.util.HashMap;
import java.util.Map;

@ControllerAdvice
public class GlobalExceptionResolver {

    //    跳转错误页面
    @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;
    }
测试结果
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