开发笔记——ServletFileUpload

最新推荐文章于 2024-05-23 16:06:46 发布

原创最新推荐文章于 2024-05-23 16:06:46 发布 · 450 阅读

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CC 4.0 BY-SA版权

本文介绍了一个使用Servlet处理图片上传的示例代码。该示例通过Apache Commons FileUpload库解析请求中的文件，并将其保存到服务器指定目录。同时展示了如何获取上传文件的路径。

1.下面是一个servlet,在dopost方法中处理图片上传

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;

import com.bluetorch.image.service.ImageService;

/**
 * Servlet implementation class RegisterController
 */
@WebServlet(name = "ImageServlet", urlPatterns = "/Image")
public class ImageServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;
	Logger logger = Logger.getLogger(this.getClass());

	/**
	 * @see HttpServlet#HttpServlet()
	 */
	public ImageServlet() {

		super();
	}

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		doPost(request, response);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		request.setCharacterEncoding("UTF-8");
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/xml");
		
		String url = new Upload(request).getUrl();
		System.out.println(url);
		}

	@Override
	public void init() throws ServletException {

	}
}

2.Upload类

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.log4j.Logger;

public class Upload {

	Logger logger = null;
	HttpServletRequest request = null;
	public Upload(HttpServletRequest request){
		this.request = request;
		this.logger = Logger.getLogger(Upload.class);
	}
	
	//得到图片文件的路径
	public String getUrl() {
		String paramValue = "";
		String folder = "/upload";
		String path = request.getSession().getServletContext().getRealPath(folder);
		
		logger.debug("<path>" + path);
		System.out.println("<path>" + path);
		
		
		DiskFileItemFactory factory = new DiskFileItemFactory();
		factory.setRepository(new File(path));
		factory.setSizeThreshold(1024*1024);
		ServletFileUpload upload = new ServletFileUpload(factory);
		upload.setSizeMax(1024*1024*10);//最大上传10M
		String name = null;
		String filename = null;
		try {
			List<FileItem> itemList = (List<FileItem>) upload.parseRequest(request);
			
			for(FileItem item : itemList){
				name = item.getFieldName();
				if(item.isFormField()){
				}else{
					String value = item.getName();
					if("".equals(value)){
						return null;
					}
					int start = value.lastIndexOf("\\");
					filename = value.substring(start + 1);
					
					OutputStream out = new FileOutputStream(new File(path, filename));
					InputStream in;
					in = item.getInputStream();

					int length = 0;
					byte[] buf = new byte[1024];

					logger.debug("获取上传文件的总共的容量：" + item.getSize());

					// in.read(buf) 每次读到的数据存放在 buf 数组中
					while ((length = in.read(buf)) != -1) {
						// 在 buf 数组中 取出数据 写到 （输出流）磁盘上
						out.write(buf, 0, length);
					}

					in.close();
					out.close();

				}
			}
		} catch (FileUploadException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	
		
		return getDefaultUrl(filename, folder);
	}
	
	//得到系统图片的路径
	public String getDefaultUrl(String img, String folder){
		
		StringBuffer sb = new StringBuffer();
		sb.append("http://");
//		sb.append(request.getLocalAddr());
		sb.append(request.getServerName());
//		sb.append("域名");
		sb.append(":");
		sb.append(request.getServerPort());
		sb.append(request.getContextPath());
		sb.append(folder);
		sb.append("/");
		sb.append(img);
		
		logger.debug("<path>" + sb.toString());
		return sb.toString();
		
	}

}

这样就完成了，但是我在部署的时候出现了一些问题，如果用IDE工具部署的话，path的路径指向的是IDE工具生成的一个临时文件夹，得到的图片路径找不到图片。

直接用tomcat部署的话，就没问题了