Struts2类型转换500错误 亟待解决

Agile牧 2010-02-21 10:39:07
package com.fairy;
// User.java
public class User {
private String name;
private String pass;

public User(String name , String pass)
{
this.name = name;
this.pass = pass;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getPass() {
return pass;
}

public void setPass(String pass) {
this.pass = pass;
}


}

package com.fairy;
// LoginAction.java
import com.opensymphony.xwork2.Action;

public class LoginAction implements Action
{
//User类型属性封装请求参数
private User user;
private String tip;
//user属性的setter和getter方法
public void setUser(User user)
{
this.user = user;
}
public User getUser()
{
return (this.user);
}
//tip属性的setter和getter方法
public void setTip(String tip)
{
this.tip = tip;
}
public String getTip()
{
return (this.tip);
}
//处理用户请求的execute方法
public String execute() throws Exception
{
//通过user属性的name属性和pass属性来决定转向
if (getUser().getName().equals("aoxiang")
&& getUser().getPass().equals("aoxiang"))
{
setTip("转换成功");
return SUCCESS;
}
else
{
setTip("转换失败");
return ERROR;
}
}
}


<!--struts.xml-->
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.1//EN"
"http://struts.apache.org/dtds/struts-2.1.dtd">
<struts>
<package name="com.fairy" extends="struts-default">
<action name="login" class="com.fairy.LoginAction">
<result name="success">/welcome.jsp</result>
<result name="error">/welcome.jsp</result>
</action>
<action name="">
<result name="success">.</result>
</action>
</package>
</struts>


<!--input.jsp-->
<%@ page language="java" contentType="text/html; charset=UTF-8"%>

<html>
<head>
<title>直接封装成对象</title>
</head>

<body>
<form action="login.action" method="post">
<table align="center" width="360">
<caption>
<h3>
直接封装成Object
</h3>
</caption>
<tr>
<td>
用户名:
<input type="text" name="user.name" />
</td>
</tr>
<tr>
<td>
密  码:
<input type="text" name="user.pass" />
</td>
</tr>
<tr align="center">
<td>
<input type="submit" value="转换" />
<input type="reset" value="重填" />
</td>
</tr>
</table>
</form>
</body>
</html>




<!--welcome.jsp-->
<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<%@taglib prefix="s" uri="/struts-tags"%>

<html>
<head>
<title>转换结果</title>
</head>

<body>
<s:property value="tip" /><br />
用户名为:<s:property value="user.name"/><br />
密码为:<s:property value="user.pass"/><br />
</body>
</html>


Tomcat的错误提示:
HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

java.lang.NullPointerException
com.fairy.LoginAction.execute(LoginAction.java:32)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:441)
com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:280)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:243)
com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:165)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:252)
org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:179)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:130)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:165)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:179)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237)
org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:488)
org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:395)

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.24 logs.
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SambaGao 2010-02-22
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1.
不建议public class LoginAction implements Action
改为 public class LoginAction implements ActionSupport
引用 2 楼 winit 的回复:
if (!null == getUser() && "aoxiang".equals(getUser().getName())
            && "aoxiang".equals(getUser().getPass()))
z这样就不会有空指针异常了
winit 2010-02-21
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if (!null == getUser() && "aoxiang".equals(getUser().getName())
&& "aoxiang".equals(getUser().getPass()))
z这样就不会有空指针异常了
litaisheng001 2010-02-21
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不行 加上一个转换器看看 既然出空指针异常说明user实体没有封装得到

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