基础框架 SpringMVC异常处理

旧城等待， 2023-01-01 11:57 180阅读 0赞

## 基础框架 SpringMVC异常处理 ##

### 异常处理分析 ###

系统中异常分为两类：编译异常 与 运行时异常。
    其中运行时异常有可以分为可预测异常与未预测到的异常。
    当Controller调用的service或者dao层抛出异常，如果直接抛到页面则不是很友好，而且存在一定风险，为此springmvc提供了异常处理方式。

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3NTgzNjU1_size_16_color_FFFFFF_t_70][推荐35个非常有创意的404错误页面][35_404]

### 案例验证 ###

1.  项目结构  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3NTgzNjU1_size_16_color_FFFFFF_t_70 1]
2.  maven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.hello</groupId>
        <artifactId>springmvc_exception</artifactId>
        <version>1.0-SNAPSHOT</version>
        <packaging>war</packaging>
    
        <name>springmvc_exception Maven Webapp</name>
        
        <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>
            <spring.version>5.0.2.RELEASE</spring.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context</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-webmvc</artifactId>
                <version>${spring.version}</version>
            </dependency>
    
            <dependency>
                <groupId>javax.servlet</groupId>
                <artifactId>servlet-api</artifactId>
                <version>2.5</version>
                <scope>provided</scope>
            </dependency>
    
            <dependency>
                <groupId>javax.servlet.jsp</groupId>
                <artifactId>jsp-api</artifactId>
                <version>2.0</version>
                <scope>provided</scope>
            </dependency>
        </dependencies>
    
        <build>
            <finalName>springmvc_day02_03_exception</finalName>
            <pluginManagement>
                <plugins>
                    <plugin>
                        <artifactId>maven-clean-plugin</artifactId>
                        <version>3.0.0</version>
                    </plugin>
                    
                    <plugin>
                        <artifactId>maven-resources-plugin</artifactId>
                        <version>3.0.2</version>
                    </plugin>
                    <plugin>
                        <artifactId>maven-compiler-plugin</artifactId>
                        <version>3.7.0</version>
                    </plugin>
                    <plugin>
                        <artifactId>maven-surefire-plugin</artifactId>
                        <version>2.20.1</version>
                    </plugin>
                    <plugin>
                        <artifactId>maven-war-plugin</artifactId>
                        <version>3.2.0</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>
            </pluginManagement>
        </build>
    </project>

1.  web.xml

<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd" >
    
    <web-app>
        <display-name>Archetype Created Web Application</display-name>
    
        
        <filter>
            <filter-name>characterEncodingFilter</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>characterEncodingFilter</filter-name>
            <url-pattern>/*</url-pattern>
        </filter-mapping>
    
        
        <servlet>
            <servlet-name>dispatcherServlet</servlet-name>
            <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
            <init-param>
                <param-name>contextConfigLocation</param-name>
                <param-value>classpath:springmvc.xml</param-value>
            </init-param>
            <load-on-startup>1</load-on-startup>
        </servlet>
        <servlet-mapping>
            <servlet-name>dispatcherServlet</servlet-name>
            <url-pattern>/</url-pattern>
        </servlet-mapping>
    
    </web-app>

1.  springmvc.xml

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    
        
        <context:component-scan base-package="com.hello"/>
    
        
        <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
            <property name="prefix" value="/WEB-INF/pages/"/>
            <property name="suffix" value=".jsp"/>
        </bean>
    
        
        <mvc:resources location="/css/" mapping="/css/**"/>
        <mvc:resources location="/images/" mapping="/images/**"/>
        <mvc:resources location="/js/" mapping="/js/**"/>
    
        
        <bean id="sysExceptionResolver" class="com.hello.exception.SysExceptionResolver"/>
    
        
        <mvc:annotation-driven/>
    
    </beans>

1.  自定义异常处理器

测试Controller

/** * 异常测试 * * @author zrj * @date 2021/1/2 * @since V1.0 **/
    @Controller
    @RequestMapping("/user")
    public class UserController { 
        /** * 异常测试 * * @return * @throws SysException */
        @RequestMapping("/testException")
        public String testException() throws SysException { 
            System.out.println( "testException执行了..." );
    
            /** * 异常不处理直接向上抛，异常会返回前端页面 * 如果配置了异常处理器SysExceptionResolver则会按照异常处理器定义业务逻辑处理 */
            //int a = 10 / 0;
    
            try { 
                // 模拟异常
                int a = 10 / 0;
            } catch (Exception e) { 
                // 打印异常信息
                e.printStackTrace();
                // 抛出自定义异常信息
                throw new SysException( "查询所有用户出现错误了..." );
            }
    
    
            return "success";
        }
    
    }

自定义异常类

/** * 自定义异常类 * * @author zrj * @date 2021/1/2 * @since V1.0 **/
    public class SysException extends Exception { 
    
        // 存储提示信息的
        private String message;
    
        @Override
        public String getMessage() { 
            return message;
        }
    
        public void setMessage(String message) { 
            this.message = message;
        }
    
        public SysException(String message) { 
            this.message = message;
        }
    
    }

自定义异常处理器

/** * 自定义异常处理器 * * @author zrj * @date 2021/1/2 * @since V1.0 **/
    public class SysExceptionResolver implements HandlerExceptionResolver { 
    
        /** * 处理异常业务逻辑 * * @param request * @param response * @param handler * @param ex * @return */
        @Override
        public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) { 
            // 获取到异常对象
            SysException e = null;
            if (ex instanceof SysException) { 
                e = (SysException) ex;
            } else { 
                e = new SysException( "系统错误，请与系统管理员联系！" );
            }
            // 创建ModelAndView对象
            ModelAndView mv = new ModelAndView();
            mv.addObject( "errorMsg", e.getMessage() );
            mv.setViewName( "error" );
            return mv;
        }
    
    }

1.  自定义异常页面  
    index.jsp

<%--
      Created by IntelliJ IDEA.
      User: zrj
      Date: 2021/1/2
      Time: 16:58
      To change this template use File | Settings | File Templates.
    --%>
    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
    <head>
        <title>index</title>
    </head>
    <body>
        <h3>异常处理</h3>
    
        <a href="user/testException" >异常处理</a>
    
    </body>
    </html>

error.jsp

<%--
      Created by IntelliJ IDEA.
      User: zrj
      Date: 2021/1/2
      Time: 16:58
      To change this template use File | Settings | File Templates.
    --%>
    <%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
    <html>
    <head>
        <title>Title</title>
    </head>
    <body>
    
        ${ errorMsg}
    
    </body>
    </html>

success.jsp

<%--
      Created by IntelliJ IDEA.
      User: zrj
      Date: 2021/1/2
      Time: 16:58
      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>
    
        <h3>执行成功</h3>
    
    </body>
    </html>

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[35_404]: /images/20221120/b46968e0bb5a434aa57a8a02e71f7426.png
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