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自己写的一个JSP上传文件和下载文件的JavaBean
摘要: 自己写的一个JSP上传文件和下载文件的JavaBean
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-1);
fos.close();
}
/**
* 获取上传的文件buffer,结尾处将多一个换行符
* @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,结尾处多一个换行符
* @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()) {
System.out.println(readStreamLineAsString(bis)); // skip a line
System.out.println(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;
System.out.println(new String(lineData,"ASCII"));
while(!isByteArraystartWith(lineData, lineSeparatorByte)) {
lineData = readStreamLine(bis);
if(lineData == null)
return null;
System.out.println(new String(lineData,"ASCII"));
}
}
}
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 && b != '\n') {
bos.write(b);
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
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：
<%
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");
}