SSH学习（五）Struts2文件上传

原文来自搬砖工，如需转载请注明出处

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博主SSH框架专栏请戳这里http://blog.csdn.net/column/details/14227.html

一、使用commons-fileupload上传文件

commons-fileupload是一个开源框架，要使用该项目实现文件上传需要使用两个文件：

1.commons-io.jar

2.commons-fileupload.jar

实现上传文件的步骤如下：

1.创建上传页面，注意form表单的enctype的属性值应为“multipart/form-data”

2.创建servlet调用commons-fileupload API实现文件上传 

示例代码如下：

上传页面form表单

	

		

			
File:
			

		
		

			

		
	

然后创建一个servlet，重新UploadServlet的doPost方法：

public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

	FileItemFactory factory = new DiskFileItemFactory();
	ServletFileUpload upload = new ServletFileUpload(factory);
	try {
		List items = upload.parseRequest(request);
		Iterator iter = items.iterator();
		while(iter.hasNext()){
			FileItem item = (FileItem) iter.next();
			if(item.isFormField()){
				System.out.println(item.getFieldName());
			}else{
				System.out.println(item.getFieldName());
				String filename = item.getName();
				System.out.println(filename);
				
				String path = this.getServletContext().getRealPath("\\file");
				File file = new File(path+"\\"+filename);
				
				item.write(file);
			}
		}
	} catch (Exception e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
}

注意：表单在设置参数的时候必须加上method=post，否则后台会报错。

二、使用Struts2上传文件

首先创建一个UploadAction

package com.study.action;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class UploadAction extends ActionSupport{
	private File upload;
	private String uploadContentType;
	private String uploadFileName;
	private String savePath;
	
	
	public String execute() throws Exception {
		String path = this.getSavePath();
		String filename = this.getUploadFileName();
		System.out.println(path);
		System.out.println(filename);
		FileOutputStream out = new FileOutputStream(path+"//"+filename);
		FileInputStream in = new FileInputStream(this.getUpload());
		byte[]b = new byte[in.available()];
		in.read(b);
		out.write(b);
		in.close();
		out.close();
		return SUCCESS;
	}
	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;
	}
	public String getSavePath() {
		savePath = ServletActionContext.getServletContext().getRealPath("//file");
		return savePath;
	}
	public void setSavePath(String savePath) {
		this.savePath = savePath;
	}
	
}

在Action中包含了如下参数，一个File对象upload，文件名称uploadFileName，ContentType是uploadContentType还有一个保存路径savePath。在Struts2中，根据特有的命名规则，根据upload文件对象就可以给uploadFileName赋真实的文件名称。而upload实际中是取得的一个临时文件。最后保存到我们指定的路径下。

struts.xml中的配置：

	
	 
		
			/Success.jsp
			/file
		
	
    

在配置中，我们指定一个临时文件路径struts.multipart.saveDir，自己创建一个文件夹来当做临时文件夹。临时文件在文件操作完毕后会自动删除。然后我们在action中声明一个参数savePath，它的值就是/file。对于如何根据upload取得uploadFileName，大家可以理解为将upload当做参数{1}，然后文件名属性就是*FileName。其他的同理。

然后就是一个简单的jsp页面

	

		

			
File:
			

		
		

			

		
	

注意，在这里的input就必须定义名称name，它的值就是我们后台所命名的属性值名称。

三、多个文件上传

对于同时提交多个文件，我们需要把Action中的属性定义为数组类型或list类型。在文件读写的时候用for循环取出所有文件即可，如：

package com.study.action;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import com.opensymphony.xwork2.ActionSupport;

public class UploadAction extends ActionSupport{
	private File[] upload;
	private String[] uploadContentType;
	private String[] uploadFileName;
	private String savePath;
	public String execute() throws Exception {
		String path = this.getSavePath();
		for (int i = 0; i < upload.length; i++) {
			String filename = this.getUploadFileName()[i];
			System.out.println(path);
			System.out.println(filename);
			FileOutputStream out = new FileOutputStream(path+"//"+filename);
			FileInputStream in = new FileInputStream(this.getUpload()[i]);
			byte[]b = new byte[in.available()];
			in.read(b);
			out.write(b);
			in.close();
			out.close();
		}
		
		return SUCCESS;
	}
	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;
	}
	public String getSavePath() {
		return savePath;
	}
	public void setSavePath(String savePath) {
		this.savePath = savePath;
	}
}

注：在Struts2中还可以使用它的标签来作文件上传