注：如果代码中的配置有些看不懂的，可以去看我之前写的Struts2配置，其他的我都会做出解释

1、全局图片

2、struts.xml （主配置文件） 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
	"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
	"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
	<!-- 这是设置你上传文件的大小的常量配置  这两点都必须写上，不然你上传的文件稍微大点都会报错 -->			
	<constant name="struts.multipart.maxSize" value="100000000000"></constant>
	<package name="struts-upload" namespace="/" extends="struts-default">
		<!-- 全局结果集配置，如果返回error就从定向到error.jsp页面 -->
		<global-results>
			<result name="error" type="redirect">/error.jsp</result>
		</global-results>
				
		<action name="StrutsUploadAction" class="StrutsUploadAction" method="execute">
			<!-- 这是设置你上传文件的大小的配置 -->			
			<interceptor-ref name="defaultStack">
				<param name="fileUpload.maximumSize">500000000</param>	
			</interceptor-ref>	
			<result name="success" type="redirect">/success.jsp</result>
		</action>
	</package>

</struts>

3、error.jsp （上传失败的jsp）

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
	<h1>上传失败</h1>
</body>
</html>

4、success.jsp  （上传成功的jsp）

4、success.jsp  （上传成功的jsp）
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
	<h1>上传成功</h1>
</body>
</html>

5、upload.jsp （上传jsp，这里说一点：form的enctype值必须是multipart/form-data）


<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
	<form action="${pageContext.request.contextPath }/StrutsUploadAction" method="post" enctype="multipart/form-data">
		<input type="file" name="upload"> <br/>		
		<input type="submit" value="上传">
	</form>
</body>
</html>

6、StrutsUploadAction.java （这里先给出最基础的Action，最好是看到这里停下来，然后用上面的代码 + 这个Action就自己去写出上传的全部，如果是会简单的java上传文件，那么你就可以写出来了）

import java.io.File;

import com.opensymphony.xwork2.ActionSupport;

public class StrutsUploadAction extends ActionSupport{

	private File upload;				//得到上传的文件
	private String uploadContentType;	//得到上传文件的类型
	private String uploadFileName;		//得到上传文件的名称
	
	@Override
	public String execute() throws Exception {

		System.out.println("filename   :" + this.getUploadFileName());
		System.out.println("uploadType    :" + this.getUploadContentType());
		System.out.println("file" + this.getUpload());
		
		
		
		return SUCCESS;
	}

	//get / set  
	public File getUpload() {
		return upload;
	}

	public void setUpload(File upload) {
		this.upload = upload;
	}

	public String getUploadContentType() {
		return uploadContentType;
	}


	public void setUploadContentType(String uploadContentType) {
		this.uploadContentType = uploadContentType;
	}

	public String getUploadFileName() {
		return uploadFileName;
	}

	public void setUploadFileName(String uploadFileName) {
		this.uploadFileName = uploadFileName;
	}
	
}

 

7、如果看到这里你还是写不出完整的上传，也没有关系。下面我会把完整的Action给你，你可以参考的看看 （代码亲测有效）

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;

import org.apache.commons.io.IOUtils;
import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class StrutsUploadAction extends ActionSupport{

	private File upload;				//得到上传的文件
	private String uploadFileName;		//得到上传文件的名称
	
	@Override
	public String execute() throws Exception {

		//这个upload的路径是相对于WebContent下的	
		String path = ServletActionContext.getServletContext().getRealPath("/upload");	
		//准备这个文件的文件名	
		String filename = UUID.randomUUID().toString() + "." +this.getUploadFileName().substring(this.getUploadFileName().lastIndexOf(".")+1);
				
		OutputStream out = new FileOutputStream(path + "/" + filename);
		InputStream in = new FileInputStream(upload);
		IOUtils.copy(in, out);
		
		in.close();
		out.close();
		
		
		return SUCCESS;
	}

	//get / set  
	public File getUpload() {
		return upload;
	}

	public void setUpload(File upload) {
		this.upload = upload;
	}

	public String getUploadFileName() {
		return uploadFileName;
	}

	public void setUploadFileName(String uploadFileName) {
		this.uploadFileName = uploadFileName;
	}
	
}

如果还有问题，可以给我留言或者联系我，我会尽可能的帮你解决的。