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Servlet中使用getInputStream进行文件上传

2016-05-07 11:45 351 查看

据说古老了点，所以代码比较繁琐，主要用于处理文件的地方太多。

下节用SERVLET3.0的Part进行操作一下。

form.html:

<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html ;charset=UTF-8">
</head>
<body>
<form method="post" action="upload.do" enctype="multipart/form-data">
file: <input type="file" name="filename" value="" /><br>
<input type="submit" value="Upload" name="upload" />
</form>
</body>
</html>

uploadServlet.java:

package cc.openhome;

import java.io.DataInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
* Servlet implementation class UploadServlet
*/
@WebServlet("/upload.do")
public class UploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#HttpServlet()
*/
public UploadServlet() {
super();
// TODO Auto-generated constructor stub
}

/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
byte[] body = readBody(request);
String textBody = new String(body, "ISO-8859-1");
String filename = getFilename(textBody);
Position p = getFilePosition(request, textBody);
writeTo(filename, body, p);
}

class Position {
int begin;
int end;
Position(int begin, int end) {
this.begin = begin;
this.end = end;
}
}

private byte[] readBody(HttpServletRequest request)
throws IOException{
int formDataLength = request.getContentLength();
DataInputStream dataStream = new DataInputStream(request.getInputStream());
byte body[] = new byte[formDataLength];
int totalBytes = 0;
while (totalBytes < formDataLength) {
int bytes = dataStream.read(body, totalBytes, formDataLength);
totalBytes += bytes;
}
return body;
}

private Position getFilePosition(HttpServletRequest request, String textBody) throws IOException {

String contentType = request.getContentType();
String boundaryText = contentType.substring(
contentType.lastIndexOf("=") + 1, contentType.length());
int pos = textBody.indexOf("filename=\"");
pos = textBody.indexOf("\n", pos) + 1;
pos = textBody.indexOf("\n", pos) + 1;
pos = textBody.indexOf("\n", pos) + 1;
int boundaryLoc = textBody.indexOf(boundaryText, pos) -4;
int begin = ((textBody.substring(0,
pos)).getBytes("ISO-8859-1")).length;
int end = ((textBody.substring(0,
boundaryLoc)).getBytes("ISO-8859-1")).length;

return new Position(begin, end);
}

private String getFilename(String reqBody) {
String filename = reqBody.substring(
reqBody.indexOf("filename=\"") + 10);
filename = filename.substring(0, filename.indexOf("\n"));
filename = filename.substring(
filename.lastIndexOf("\\") + 1, filename.indexOf("\""));
return filename;
}

private void writeTo(String filename, byte[] body, Position p)
throws FileNotFoundException, IOException {
FileOutputStream fileOutputStream =
new FileOutputStream("c:/workspace/" + filename);
fileOutputStream.write(body, p.begin, (p.end - p.begin));
fileOutputStream.flush();
fileOutputStream.close();

}

}

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