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springMVC实现全局异常(完整demo)

程序员文章站 2023-12-22 16:20:16
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springMVC实现全局异常(完整demo)

一.为什么会有全局异常

​ 在工作过程中,为了更好的处理业务中出现的异常,经常会使用自定义异常的方式,但是过多的抛出自定义异常,并try{}catch(){} 会使代码看起来臃肿、冗余,那么全局异常便应用而出了,全局异常很好的解决了这些问题。

二.springMVC实现全局异常的3中方式

  • 使用Spring MVC提供的SimpleMappingExceptionResolver
  • 实现Spring的异常处理接口HandlerExceptionResolver 自定义自己的异常处理器
  • 使用@ExceptionHandler注解实现异常处理

笔者这里提供的是第二种,通过实现HandlerExceptionResolver接口实现全局异常,废话少说直接上代码

1.创建maven web项目

springMVC实现全局异常(完整demo)

2.pom中添加依赖 mvc依赖 web依赖 servlet依赖
<?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>com.shsxt</groupId>
  <artifactId>springmvc01</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>web Maven Webapp</name>

  <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>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>
    <!-- spring web 依赖 -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>4.3.2.RELEASE</version>
    </dependency>

    <!-- spring mvc 依赖 -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>4.3.2.RELEASE</version>
    </dependency>

    <!-- web servlet 依赖 -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.0.1</version>
    </dependency>

  </dependencies>

  <!-- jetty 插件 -->
  <build>
    <finalName>web</finalName>
    <plugins>
      <plugin>
        <groupId>org.mortbay.jetty</groupId>
        <artifactId>maven-jetty-plugin</artifactId>
        <version>6.1.25</version>
        <configuration>
          <scanIntervalSeconds>10</scanIntervalSeconds>
          <-- 项目访问路径 如:localhost:8000/web -->
          <contextPath>/web</contextPath>
        </configuration>
      </plugin>
    </plugins>

  </build>
</project>
3.自定义异常类
package cn.cui.test;

//自定义异常类 继承RuntimeException
public class LoginException extends RuntimeException{
    private Integer code = 300;
    private String msg = "参数异常";

    public LoginException() {
        super();
    }
    public LoginException(String msg) {
        super("参数异常");
        this.msg = msg;
    }
    public LoginException(Integer code, String msg) {
        super();
        this.code = code;
        this.msg = msg;
    }

    public Integer getCode() {
        return code;
    }

    public void setCode(Integer code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

}
4.编写全局异常类
package cn.cui.test;

import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;

/**
* 实现HandlerExceptionResolver接口 重写resolveException方法
* 通过@Component表示捕获异常后执行这个类 或者可以通过在 mvc配置文件中加入
* <bean *id="handlerExceptionResolver" class="cn.cui.test.GlobalException"/>
*
**/

@Component
public class GlobalException implements HandlerExceptionResolver {
    @Override
    public ModelAndView resolveException(
        javax.servlet.http.HttpServletRequest httpServletRequest,
        javax.servlet.http.HttpServletResponse httpServletResponse,
                                         Object o, Exception e) {
	
       //通过 instanceof 方法判断捕获的异常是否是自定义的LoginException异常
       if (e instanceof  LoginException)
           System.out.println(((LoginException) e).getMsg()+":"+((LoginException) e).getCode());
        
        return null;
    }
}

5.spring-context配置文件
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd
        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.xsd
        http://www.springframework.org/schema/aop
        http://www.springframework.org/schema/aop/spring-aop.xsd">
    <!-- 扫描com.shsxt.controller 下包 -->
    <context:component-scan base-package="cn.cui.test" />
    <!-- mvc 请求映射 处理器与适配器配置-->
    <mvc:annotation-driven/>

    <!--配置视图解析器  默认的视图解析器- -->
    <bean id="defaultViewResolver"
          class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
        <property name="contentType" value="text/html" />
        <property name="prefix" value="/WEB-INF/jsp/" />
        <property name="suffix" value=".jsp" />
    </bean>
	<-- 全局异常类中没有配置component 就配置这个bean -->
    <bean id="handlerExceptionResolver" class="cn.cui.test.GlobalException"/>
</beans>
6.web.xml配置
<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="3.0"
         xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
    http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">

  <!-- 表示容器启动时 加载上下文配置  这里指定spring 相关配置 -->
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:*.xml</param-value>
  </context-param>

  <!-- 启用spring容器环境上下文监听 -->
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>

  <!-- 编码过滤 utf-8 -->
  <filter>
    <description>char encoding filter</description>
    <filter-name>encodingFilter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
      <param-name>encoding</param-name>
      <param-value>UTF-8</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>encodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

  <!-- servlet请求分发器 -->
  <servlet>
    <servlet-name>springMvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:spring-context.xml</param-value>
    </init-param>
    <!-- 表示启动容器时初始化该Servlet -->
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>springMvc</servlet-name>
    <!-- 这是拦截请求, /代表拦截所有请求 -->
    <url-pattern>/</url-pattern>
  </servlet-mapping>
</web-app>
7.抛出异常测试类
package cn.cui.test;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class ProductException {

    @RequestMapping("/test")
    public void testEx(){
        if (true)
            throw new LoginException(200,"未登录");
    }
}

8.启动项目

springMVC实现全局异常(完整demo)

9.本地浏览器访问

springMVC实现全局异常(完整demo)springMVC实现全局异常(完整demo)

执行操作了全局异常的打印方法。

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