java中提供了io類庫，可以輕松的用java實現對文件的各種操作。下面就來說一下如何用java來實現這些操作。
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新建目錄

  1. <%@ page contentType="text/html;charset=gb2312"%>
  2. <%
  3. //String URL = request.getRequestURI();
  4. String filePath="C:\\測試\\";
  5. filePath=filePath.toString();//中文轉換
  6. java.io.File myFilePath=new java.io.File(filePath);
  7. if(!myFilePath.exists())
  8. myFilePath.mkdir();
  9. %>

新建文件

  1. <%@ page contentType="text/html;charset=gb2312"%>
  2. <%@ page import="java.io.*" %>
  3. <%
  4. String filePath="c:/測試/newFile.txt";
  5. filePath=filePath.toString();
  6. File myFilePath=new File(filePath);
  7. if(!myFilePath.exists())
  8. myFilePath.createNewFile();
  9. FileWriter resultFile=new FileWriter(myFilePath);
  10. PrintWriter myFile=new PrintWriter(resultFile);
  11. String content ="這是測試數據";
  12. String strContent = content.toString();
  13. myFile.println(strContent);
  14. resultFile.close();
  15. %>


刪除文件

  1. <%@ page contentType="text/html;charset=gb2312"%>
  2. <%
  3. String filePath="c://測試//newFile.txt";
  4. filePath=filePath.toString();
  5. java.io.File myDelFile=new java.io.File(filePath);
  6. if(myDelFile.exists())
  7. {??
  8. ??? myDelFile.delete();
  9. ??? out.println(filePath+"刪除成功！！！");
  10. }
  11. else
  12. {
  13. ??? out.println(filePath+"該文件不存在");
  14. }
  15. %>

文件拷貝

  1. <%@ page contentType="text/html; charset=gb2312" %>
  2. <%@ page import="java.io.*" %>
  3. <%
  4. int bytesum=0;
  5. int byteread=0;
  6. //file:讀到流中
  7. InputStream inStream=new FileInputStream("c://測試//newFile.txt");
  8. FileOutputStream fs=new FileOutputStream( "c://測試//copyFile.txt");
  9. byte[]? buffer =new? byte[1444];
  10. int length;
  11. while ((byteread=inStream.read(buffer))!=-1)
  12. ?{
  13. ?? out.println("<DT><B>"+byteread+"</B></DT>");
  14. ?? bytesum+=byteread;
  15. ?? out.println(bytesum);
  16. ?? fs.write(buffer,0,byteread);
  17. ?}
  18. inStream.close();
  19. %>

整個文件夾拷貝

  1. <%@ page contentType="text/html;charset=gb2312"%>
  2. <%@ page import="java.io.*" %>
  3. <%String url1="C:/aaa";
  4. ? String url2="d:/java/";
  5. ? (new File(url2)).mkdirs();
  6. ?File[] file=(new File(url1)).listFiles();
  7. ?for(int i=0;i<file.length;i++){
  8. ? if(file[i].isFile()){
  9. ?? file[i].toString();
  10. ?? FileInputStream input=new FileInputStream(file[i]);
  11. ?? FileOutputStream output=new FileOutputStream(url2+"/"+(file[i].getName()).toString());
  12. ?? byte[] b=new byte[1024*5];
  13. ??? int len;
  14. ??? while((len=input.read(b))!=-1){
  15. ??? output.write(b,0,len);
  16. ??? }
  17. ??? output.flush();
  18. ??? output.close();
  19. ??? input.close();
  20. ? }
  21. ?}
  22. %>

文件下載

  1. <%@ page contentType="text/html; charset=gb2312"%>
  2. <%@ page import="java.io.*" %>
  3. <%
  4. ? String fileName = "newFile.txt".toString();
  5. ? //讀到流中
  6. ? InputStream inStream=new FileInputStream("c://測試//newFile.txt");
  7. ? //設置輸出的格式
  8. ? response.reset();
  9. ? response.setContentType("text/plain");
  10. ? response.addHeader("Content-Disposition","attachment; filename=\"" + fileName + "\"");
  11. ? //循環取出流中的數據
  12. ? byte[] b = new byte[100];
  13. ? int len;
  14. ? ServletOutputStream outStream = response.getOutputStream();
  16. ? while((len=inStream.read(b)) >0)
  17. ? outStream.write(b,0,len);
  18. ? outStream.flush();
  19. ? outStream.close();
  20. ? inStream.close();
  21. %>

數據庫字段中的文件下載

  1. <%@ page contentType="text/html;charset=gb2312"%>
  2. <%@ page import="java.util.*,java.sql.*,java.io.*"%>
  3. <%
  4. ??? String id = request.getParameter("id");
  5. ??? if(id==null)
  6. ??? {?? throw new Exception ("沒有找到圖片");
  7. ??? }
  8. ??? else
  9. ??? {
  10. ?????? try
  11. ?????? {
  12. com.gzrealmap.lib.jdbc.JDBCUtil? SqlBean= com.gzrealmap.lib.jdbc.JDBCUtil.getInstance();
  13. ?????????????? SqlBean.connect();
  14. ?????????????? String sql = "select * from innernews where id = '"+79+"'";
  15. ?????????????? ResultSet rs = SqlBean.queryforUpdate(sql);
  16. ?????????????? rs.next();
  17. ?????????????? //String fileNamedb = rs.getString("imageName");
  18. ?????????????? String file= rs.getString("acc");
  19. ?????????????? //String fileName = new String(fileNamedb.getBytes(),"iso-8859-1");
  20. ?????????????? String fileName = "a.jpg";
  21. ??????????????? response.setHeader("Content-Disposition",? "inline; filename=\"" + fileName + "\"");????
  22. ?????????????? String filter = fileName.substring(fileName.lastIndexOf("."));
  23. ??????????????
  24. ?????????????? if(filter.equals(".txt"))
  25. ?????????????? {
  26. ?????????????????? response.setContentType("text/plain");
  27. ?????????????? }
  28. ?????????????? else if(filter.equals(".doc")||filter.equals(".dot"))
  29. ?????????????? {
  30. ?????????????????? response.setContentType("application/msword");
  31. ?????????????? }
  32. ?????????????? else
  33. ?????????????? {
  34. ???????????????? response.setContentType("image/jpeg;charset=GB2312");
  35. ?????????????? }
  36. ?????????????? ServletOutputStream o = response.getOutputStream();
  37. ?????????????? //o.write(file);
  38. ?????????????? out.println(file);
  39. ?????????????? //o.flush();
  40. ?????????????? //o.close();
  41. ?????????????? SqlBean.disconnect();
  42. ?????? }
  43. ??????? catch(Exception ex)
  44. ?????? {
  45. ?????????? out.println(ex.getMessage());
  46. ?????? }
  47. ??? }??
  48. %>

把網頁保存成文件

  1. <%@ page contentType="text/html;charset=gb2312"%>
  2. <%@ page import="java.text.*,java.util.*,java.net.*,java.io.*"%>
  3. <%
  4. ?URL stdURL = null;
  5. ?BufferedReader stdIn = null;
  6. ?PrintWriter stdOut = null;
  7. ?try {
  8. ? stdURL = new URL("<a );
  9. ?}
  10. ?catch (MalformedURLException e) {
  11. ?? throw e;
  12. ?}
  14. try {
  15. ??? //將字節流轉變成為字符流
  16. ??? stdIn = new BufferedReader(new InputStreamReader(stdURL.openStream()));
  17. ??? String theFileName = "c://測試//163.html";
  18. ??? stdOut = new PrintWriter(new BufferedWriter(new FileWriter(theFileName.toString())));
  19. ?}
  20. ?catch (IOException e) {
  21. ?}
  23. ?/***把URL指定的頁面以流的形式讀出，寫成指定的文件***/
  24. ?try {
  25. ??? String strHtml = "";
  26. ?? while((strHtml = stdIn.readLine())!=null) {
  27. ?? stdOut.println(strHtml);
  28. ?? }
  29. ?}
  30. ?catch (IOException e) {
  31. ?? throw e;
  32. ?}
  33. ?finally {??
  34. ?? try {
  35. ???? if(stdIn != null)
  36. ?????? stdIn.close();
  37. ???? if(stdOut != null)
  38. ?????? stdOut.close();
  39. ?????? }
  40. ?? catch (Exception e) {
  41. ???? System.out.println(e);
  42. ?? }
  43. ?}
  44. %>

直接下載網上的文件

  1. <%@ page contentType="text/html;charset=gb2312"%>
  2. <%@ page import="java.io.*"%>
  3. <%@ page import="java.net.*"%>
  4. <%
  5. ? int bytesum=0;
  6. ? int byteread=0;
  7. ? URL url = new URL("<a );
  8. ? URLConnection conn = url.openConnection();
  9. ? InputStream inStream = conn.getInputStream();
  11. ? /**
  12. ? String theFileName = "c:/測試/logo.gif";
  13. ? theFileName = theFileName.toString();
  14. ? File myFilePath=new File(theFileName);
  15. ? if(!myFilePath.exists())
  16. ? myFilePath.createNewFile();
  17. ? **/
  19. ? FileOutputStream fs=new FileOutputStream("c:/測試/logo2.gif");
  20. ? byte[]? buffer =new? byte[1444];
  21. ??? while ((byteread=inStream.read(buffer))!=-1)
  22. ??? {
  23. ?????? out.println("<DT><B>"+byteread+"</B></DT>");
  24. ?????? bytesum+=byteread;
  25. ?????? //System.out.println(bytesum);
  26. ?????? fs.write(buffer,0,byteread);
  27. ???? }
  28. %>

按行讀文件

  1. <%@ page contentType="text/html; charset=gb2312" %>
  2. <%@ page import="java.io.*" %>
  3. <%
  4. FileReader myFileReader=new FileReader("c:/哈哈.txt");
  5. BufferedReader myBufferedReader=new BufferedReader(myFileReader);
  6. String myString=null;
  7. String resultString=new String();
  8. while((myString=myBufferedReader.readLine())!=null) {
  9. resultString=resultString+myString+"
  10. ";
  11. }
  12. out.println(resultString);
  13. myFileReader.close();
  14. %>

對word文檔的處理（上傳與下載）

  1. <%@ page contentType="application/msword" %>
  2. <!-- 以上這行設定本網頁為excel格式的網頁 -->
  3. <%
  4. ?? response.setHeader("Content-disposition","inline; filename=test1.doc"); //線上瀏覽方式
  5. ? // response.setHeader("Content-disposition","attachment; filename=test1.doc");//下載方式
  6. ?? //以上這行設定傳送到前端瀏覽器時的檔名為test1.doc
  7. ?? //就是靠這一行，讓前端瀏覽器以為接收到一個word檔
  8. %>
  9. //然后輸出動態內容就可以得到一個word文檔了

1,打開：
1）文件頭上加：

  1. <%@ page? contentType="application/msword"%>?
  3. xml文件里：
  4. <mime-mapping>
  5. ??????? <extension>doc</extension>
  6. ??????? <mime-type>application/msword</mime-type>
  7. </mime-mapping>

2）可以用js,以下代碼來自引用：

]]>




?
2，下載：

  1. <%@ page contentType="text/html;charset=gb2312" import= "java.io.*"%>
  2. <%// 得到文件名字和路徑
  3. ? String filename = "jsp.doc";
  4. ? String filepath = "C:\\";
  6. ? // 設置響應頭和下載保存的文件名
  7. ? response.setContentType("APPLICATION/OCTET-STREAM");
  8. ? response.setHeader("Content-Disposition","attachment; filename=\"" + filename + "\"");
  10. ? // 打開指定文件的流信息
  11. ? java.io.FileInputStream fileInputStream = new java.io.FileInputStream(filepath + filename);
  12. ? //FileOutputStream out? = new FileOutputStream(filepath+"測試\\" + filename);
  13. ? // 寫出流信息
  14. ? int i;
  15. ? while ((i=fileInputStream.read()) != -1) {
  16. ?? out.write(i);
  17. ? }
  18. ? fileInputStream.close();
  19. ? out.close()
  20. ?%>