Java后台-Spring MVC 异常处理-2020-12-2

• Student.java 文件的内容：

package com.tutorialspoint;
public class Student {
   private Integer age;
   private String name;
   private Integer id;
   public void setAge(Integer age) {
      this.age = age;
   }
   public Integer getAge() {
      return age;
   }
   public void setName(String name) {
      this.name = name;
   }
   public String getName() {
      return name;
   }
   public void setId(Integer id) {
      this.id = id;
   }
   public Integer getId() {
      return id;
   }
}

• SpringException.java 文件的内容：

package com.tutorialspoint;
public class SpringException extends RuntimeException{
   private String exceptionMsg;   
   public SpringException(String exceptionMsg) {
      this.exceptionMsg = exceptionMsg;
   }   
   public String getExceptionMsg(){
      return this.exceptionMsg;
   }   
   public void setExceptionMsg(String exceptionMsg) {
      this.exceptionMsg = exceptionMsg;
   }
}

• StudentController.java 文件的内容:

package com.tutorialspoint;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.ui.ModelMap;
@Controller
public class StudentController {
   @RequestMapping(value = "/student", method = RequestMethod.GET)
   public ModelAndView student() {
      return new ModelAndView("student", "command", new Student());
   }
   @RequestMapping(value = "/addStudent", method = RequestMethod.POST)
   @ExceptionHandler({SpringException.class})
   public String addStudent( @ModelAttribute("HelloWeb")Student student, 
      ModelMap model) {
      if(student.getName().length() < 5 ){
         throw new SpringException("Given name is too short");
      }else{
       model.addAttribute("name", student.getName());
      }     
      if( student.getAge() < 10 ){
         throw new SpringException("Given age is too low");
      }else{
       model.addAttribute("age", student.getAge());
      }
      model.addAttribute("id", student.getId());
      return "result";
   }
}

• 配置文件 web.xml 的内容：

<web-app id="WebApp_ID" version="2.4"
    xmlns="http://java.sun.com/xml/ns/j2ee" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

    <display-name>Spring Exception Handling</display-name>

    <servlet>
        <servlet-name>HelloWeb</servlet-name>
        <servlet-class>
           org.springframework.web.servlet.DispatcherServlet
        </servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>HelloWeb</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

• 配置文件 HelloWeb-servlet.xml 的内容:

<beans xmlns="http://www.springframework.org/schema/beans"
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-3.0.xsd
http://www.springframework.org/schema/context 
http://www.springframework.org/schema/context/spring-context-3.0.xsd">

<context:component-scan base-package="com.tutorialspoint" />

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
   <property name="prefix" value="/WEB-INF/jsp/" />
   <property name="suffix" value=".jsp" />
</bean>

<bean class="org.springframework.web.servlet.handler.
      SimpleMappingExceptionResolver">
   <property name="exceptionMappings">
      <props>
         <prop key="com.tutorialspoint.SpringException">
            ExceptionPage
         </prop>
      </props>
   </property>
   <property name="defaultErrorView" value="error"/>
</bean>

</beans>

• 视图文件 student.jsp 的内容：

<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<html>
<head>
    <title>Spring MVC Exception Handling</title>
</head>
<body>

<h2>Student Information</h2>
<form:form method="POST" action="/HelloWeb/addStudent">
   <table>
   <tr>
   <td><form:label path="name">Name</form:label></td>
   <td><form:input path="name" /></td>
   </tr>
   <tr>
   <td><form:label path="age">Age</form:label></td>
   <td><form:input path="age" /></td>
   </tr>
   <tr>
   <td><form:label path="id">id</form:label></td>
   <td><form:input path="id" /></td>
   </tr>
   <tr>
   <td colspan="2">
   <input type="submit" value="Submit"/>
   </td>
   </tr>
   </table>  
</form:form>
</body>
</html>

• 视图文件 error.jsp 的内容：

<head>
    <title>Spring Error Page</title>
</head>
<body>

<p>An error occured, please contact webmaster.</p>

</body>
</html>;

• 视图文件 ExceptionPage.jsp 的内容:

<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<html>
<head>
    <title>Spring MVC Exception Handling</title>
</head>
<body>

<h2>Spring MVC Exception Handling</h2>

<h3>${exception.exceptionMsg}</h3>

</body>
</html>

• 视图文件 result.jsp 的内容：

<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<html>
<head>
    <title>Spring MVC Form Handling</title>
</head>
<body>

<h2>Submitted Student Information</h2>
   <table>
   <tr>
   <td>Name</td>
   <td>${name}</td>
   </tr>
   <tr>
   <td>Age</td>
   <td>${age}</td>
   </tr>
   <tr>
   <td>ID</td>
   <td>${id}</td>
   </tr>
   </table>  
</body>
</html>

• 1. 访问该 URL http://localhost:8080/SpringWeb/student

image.png

• 2. 输入如上图所示的值，然后单击提交按钮。如果你的 Spring Web 应用程序一切都正常，你应该看到下面的结果：

image.png