File upload 使用Struts2上传文件（我使用的web服务器是Tomcat7）

当我使用Struts2上传文件时，我在jsp中单击了submit，但是tomcat给我显示了错误的消息，我在互联网上搜索过，但是我找不到答案，所以我希望有人能帮助我，谢谢

下面是错误的消息：

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
java.io.FileInputStream.<init>(FileInputStream.java:134)
lanxiaoxing.upload.upLoadAction.execute(upLoadAction.java:58)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:601)
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:306)
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.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)

<?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="lanxiaoxing.user" extends="struts-default">
<action name="loginUser" class="lanxiaoxing.user.userAction">
  <result name="success">success.jsp</result>
  <result name="error">error.jsp</result>
</action>
</package>
<package name="lanxiaoxing.upload" extends="struts-default">
<action name="upLoad" class="lanxiaoxing.upload.upLoadAction">
  <result name="SUCCESS">upload_success.jsp</result>
</action>
</package>
</struts>

package lanxiaoxing.upload;

import java.io.*;
import javax.servlet.http.*;
import org.apache.struts2.*;
import com.opensymphony.xwork2.*;

public class upLoadAction extends ActionSupport{

/**
 * 
 */
private static final long serialVersionUID = 1L;
private File lanxiaoxingfile;
private String lanxiaoxingfileContentType;
private String lanxiaoxingfileName;
private String savePath;


private String getSavePath(){
    HttpServletRequest request = ServletActionContext.getRequest();
    return request.getSession().getServletContext().getRealPath(savePath);
}


public File getlanxiaoxingfile(){
    return lanxiaoxingfile;
}
public void setlanxiaoxingfile(File lanxiaoxingfile){
    this.lanxiaoxingfile=lanxiaoxingfile;
}

public String getlanxiaoxingfileContentType(){
    return lanxiaoxingfileContentType;
}
public void setlanxiaoxingfileContenType(String lanxiaoxingfileContentType){
    this.lanxiaoxingfileContentType=lanxiaoxingfileContentType;
}

public String getlanxiaoxingfileName(){
    return lanxiaoxingfileName;
}
public void setlanxiaoxingfileName(String lanxiaoxingfileName){
    this.lanxiaoxingfileName=lanxiaoxingfileName;
}

public void setsavePath(String savePath){
    this.savePath=savePath;
}

public String execute() throws Exception{
    setsavePath("");

    FileOutputStream fos = new FileOutputStream(getSavePath()+"\\"+getlanxiaoxingfileName());

    FileInputStream fis = new FileInputStream(getlanxiaoxingfile());

    byte[]buffer = new byte[1024];
    int len=0;
    while((len=fis.read(buffer))>0){
        fos.write(buffer, 0, len);
    }
    return SUCCESS;
}

---

}

使用Struts2进行文件上传，但缺少

FileUpload

和

defaultStack

拦截器似乎是导致错误的原因。尝试更改您的操作声明，如：

<action name="upLoad" class="lanxiaoxing.upload.upLoadAction">
    <interceptor-ref name="fileUpload">
        <param name="maximumSize">999999999999</param>
        <param name="allowedTypes">
            image/png,image/gif,image/jpeg,image/pjpeg
        </param>
    </interceptor-ref>
    <interceptor-ref name="defaultStack"></interceptor-ref>
    <result name="success">upload_success.jsp</result>
</action>

---

 你的getter和setter名称都不正确；它们应该遵循正常的Java命名约定，以及文件上载拦截器所期望的约定，例如：

public void setLanxiaoxingfile(File lanxiaoxingfile) { // Note capital "L"

假设文件输入字段的名称为“lanxiaoxinfile”

在我看来，变量名的
“file”
部分是多余的

有关更多信息，请参阅

此外，正如tusar所说，结果名称应该是小写的
“success”
，或者只是留空，因为这是默认值。不过，默认堆栈已经包含
“fileUpload”
拦截器，因此为此操作重新配置它将是多余的，并且会产生误导

考虑通过实用程序方法进行文件复制，或者只使用其中一种方法。
似乎找不到文件。我能看看你在struts.xml和JAVA部分上的动作映射吗？我想看看这个部分
lanxiaoxing.upload.upLoadAction.execute（upLoadAction.JAVA:58）
+1，好让大家看看！我为未来的访客回复了之前的答案：）