struts2 上传时报错，求教原因？

[hollin1987]

java.lang.NullPointerException
	java.io.File.<init>(File.java:262)
	com.yiyi.action.UploadAction.upload(UploadAction.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:452)
	com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:291)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:254)
	com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:133)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:207)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:207)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:166)
	com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:314)
	com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
	org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
	org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:485)
	org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
	org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)


note The full stack trace of the root cause is available in the Apache Tomcat/6.0.18 logs.

[devin_jia]

空指针错误啊

[hollin1987]

我的uploadaction类

package com.yiyi.action;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class UploadAction extends ActionSupport{

	/**
	 * 
	 */
	private static final long serialVersionUID = -8936956951350346958L;
	
	private File picture;
	@SuppressWarnings("unused")
	private String pictureContentType;
	private String pictureFileName;
	
	public String execute(){
	 return "input";	
	}
	
	public String upload() throws Exception{
		
		File saved = new File(ServletActionContext.getServletContext().getRealPath("upload"),pictureFileName);
		InputStream ins = null;
		OutputStream ous = null;
		try {
			saved.getParentFile().mkdirs();//确保文件夹upload存在
			ins = new FileInputStream(picture);
			ous = new FileOutputStream(saved);
			byte[] b = new byte[1024]; // 字节缓存
			int len = 0 ;
			while((len = ins.read(b))!= -1){ //循环读入，直至结束
				ous.write(b,0,len);
			}
			
			
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if(ins != null ){
				try {
					ins.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			if(ous != null){
				try {
					ous.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
		
		return "list";
		
	}

}

[hollin1987]

[Quote=引用 1 楼 yewuqing007 的回复:]

空指针错误啊
[/Quote]

请问是什么原因了，我上传了文件啊,在页面提交就出现500错误

[hollin1987]

struts的配置
<package name="test" namespace="/test" extends="struts-default">
<action name="upload" class="com.yiyi.action.UploadAction" method="upload">
<result name="list">/upload_list.jsp</result>
<result name="input">/upload.jsp</result>
</action>
</package>


upload.jsp

<s:form action="test/upload" enctype="multipart/form-data" method="post">
<s:label value="上传测试"></s:label>
<s:file name="picture" label="文件："></s:file>
<s:submit value="上传" method="upload"></s:submit>
</s:form>

[hollin1988]

请教高手啊。最好说明错误的原因。需要什么文件都可以贴

[ZZZ5512536]

    private File picture;
    @SuppressWarnings("unused")
    private String pictureContentType;
    private String pictureFileName;

这些有get/set方法没？