这个周末终于可以好好锻炼一下我的IBM ThinkPad T43了。今天看了一些关于JSP,Servlet方面的资料,写了简单的两个JavaBean。一个是UpLoad,一个是DownLoad。写得很简单,没有使用其它任何组件,自己做的。大家可以来看看。
1.RunningUpLoader上传Bean
首先是RunningUpLoader.java,代码有些多,因为我是自己来解析输入流的。
package testupload; import java.io.*; import javax.servlet.http.HttpServletRequest;
public class RunningUpLoader { public RunningUpLoader() { }
/** * 上传文件 * @param request HttpServletRequest Servlet的请求对象 * @param name String 要上传的文件在表单中的参数名 * @param fileName String 保存在服务器上的文件名 * @throws IOException */ public void doUpload(HttpServletRequest request, String name,String fileName) throws IOException { InputStream in = request.getInputStream(); byte[] buffer = getFileContent(name,in); FileOutputStream fos = new FileOutputStream(fileName); fos.write(buffer,0,buffer.length-2); fos.close(); }
/** * 获取上传的文件buffer,结尾处将多2个字节 * @param name String 文件上传参数的名字 * @param is InputStream 服务器对话的输入流 * @return byte[] 返回获取的文件的buffer,结尾处将多2个字节 * @throws IOException */ private byte[] getFileContent(String name, InputStream is) throws IOException{ int index; boolean isEnd = false; byte[] lineSeparatorByte; byte[] lineData; String content_disposition; ByteArrayOutputStream bos = new ByteArrayOutputStream(); BufferedInputStream bis = new BufferedInputStream(is);
lineSeparatorByte = readStreamLine(bis); while(!isEnd) { lineData = readStreamLine(bis); if(lineData == null) { break; } content_disposition = new String(lineData,"ASCII"); index = content_disposition.indexOf("name=\"" + name + "\""); if (index >= 0 && index < content_disposition.length()) { readStreamLineAsString(bis); // skip a line readStreamLineAsString(bis); // skip a line
while ((lineData = readStreamLine(bis)) != null) { System.out.println(new String(lineData)); if (isByteArraystartWith(lineData, lineSeparatorByte)) { // end isEnd = true; break; } else { bos.write(lineData); } } }else { lineData = readStreamLine(bis); if(lineData == null) return null; while(!isByteArraystartWith(lineData, lineSeparatorByte)) { lineData = readStreamLine(bis); if(lineData == null) return null; } } } return bos.toByteArray(); }
private byte[] readStreamLine(BufferedInputStream in) throws IOException{ ByteArrayOutputStream bos = new ByteArrayOutputStream(); int b = in.read(); if(b== -1) return null; while(b != -1) { bos.write(b); if(b == ‘\n‘) break; b = in.read(); } return bos.toByteArray(); }
private String readStreamLineAsString(BufferedInputStream in) throws IOException { return new String(readStreamLine(in),"ASCII"); }
private boolean isByteArraystartWith(byte[] arr,byte[] pat) { int i; if(arr == null || pat == null) return false; if(arr.length < pat.length) return false; for(i=0;i<pat.length;i++) { if(arr[i] != pat[i]) return false; } return true; } }
上传文件文件的时候,需要在之前的html中增加一个form表单,里面需要有个<input type="file" name="fileUpload" >的输入按钮。这样,浏览器才会将要上传的文件递交给服务器。 其中name="fileUpload"的名字,就是RunnningUpLoader.doUpload函数中的name参数。
使用的时候直接用bean就OK了。比如upload.jsp如下:
<jsp:useBean id="upBean" scope="page" class="testupload.RunningUpLoader" />
<%
upBean.doUpload(request,"fileupload","runningUpLoad.txt");
%>
2. RunningDownLoader下载Bean
package testupload; import java.io.*; import javax.servlet.http.HttpServletResponse; import java.net.URLEncoder;
public class RunningDownLoader { public RunningDownLoader() { }
public void doDownload(HttpServletResponse response, String filePath,String fileName) throws IOException { response.reset();//可以加也可以不加 response.setContentType("application/x-download");//设置为下载application/x-download System.out.println(this.getClass().getClassLoader().getResource("/").getPath()); String filenamedownload = filePath; String filenamedisplay = fileName;//系统解决方案.txt filenamedisplay = URLEncoder.encode(filenamedisplay,"UTF-8"); response.addHeader("Content-Disposition","attachment;filename=" + filenamedisplay);
OutputStream output = null; FileInputStream fis = null; try { output = response.getOutputStream(); fis = new FileInputStream(filenamedownload);
byte[] b = new byte[1024]; int i = 0;
while((i = fis.read(b)) > 0) { output.write(b, 0, i); } output.flush(); } catch(Exception e) { System.out.println("Error!"); e.printStackTrace(); } finally { if(fis != null) { fis.close(); fis = null; } if(output != null) { output.close(); output = null; } }
}
}
下载文件,最好是做到Servlet上。直接在Servlet的doGet下面增加如下代码即可
//Process the HTTP Get request public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { RunningDownLoader downloader= new RunningDownLoader(); downloader.doDownload(response,"E:\\MyProjects\\testupload.rar","upload.bin"); }
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