Java对各种文件的操作详解

Java对各种文件的操作详解

时间：2006-5-15

<script type="text/javascript"> </script> <script src="http://pagead2.googlesyndication.com/pagead/show_ads.js" type="text/javascript"> </script> name="google_ads_frame" marginwidth="0" marginheight="0" src="http://pagead2.googlesyndication.com/pagead/ads?client=ca-pub-8907903490048952&dt=1151053741468&lmt=1147677889&prev_fmts=728x90_as%2C160x90_0ads_al&format=468x60_as&output=html&url=http%3A%2F%2Fwww.zebcn.com%2Fhtml%2F200605%2F3336.html&color_bg=EDF0F5&color_text=000000&color_link=DE7008&color_url=666666&color_border=EDF0F5&ad_type=text_image&ref=http%3A%2F%2Fwww.zebcn.com%2Fhtml%2F75%2F20.html&cc=118&u_h=768&u_w=1024&u_ah=738&u_aw=1024&u_cd=32&u_tz=480&u_java=true" frameborder="0" width="468" scrolling="no" height="60" allowtransparency="allowtransparency">   Web www.zebcn.com java中提供了io类库，可以轻松的用java实现对文件的各种操作。下面就来说一下如何用java来实现这些操作。   新建目录<%@ page contentType="text/html;charset=gb2312"%> <% //String URL = request.getRequestURI(); String filePath="C://测试//"; filePath=filePath.toString();//中文转换 java.io.File myFilePath=new java.io.File(filePath); if(!myFilePath.exists()) myFilePath.mkdir(); %>   新建文件 <%@ page contentType="text/html;charset=gb2312"%> <%@ page import="java.io.*" %> <% String filePath="c:/测试/newFile.txt"; filePath=filePath.toString(); File myFilePath=new File(filePath); if(!myFilePath.exists()) myFilePath.createNewFile(); FileWriter resultFile=new FileWriter(myFilePath); PrintWriter myFile=new PrintWriter(resultFile); String content ="这是测试数据"; String strContent = content.toString(); myFile.println(strContent); resultFile.close(); %>   删除文件<%@ page contentType="text/html;charset=gb2312"%> <% String filePath="c://测试//newFile.txt"; filePath=filePath.toString(); java.io.File myDelFile=new java.io.File(filePath); if(myDelFile.exists()) {       myDelFile.delete();     out.println(filePath+"删除成功！！！"); } else {     out.println(filePath+"该文件不存在"); } %> 文件拷贝<%@ page contentType="text/html; charset=gb2312" %> <%@ page import="java.io.*" %> <% int bytesum=0; int byteread=0; //file:读到流中 InputStream inStream=new FileInputStream("c://测试//newFile.txt"); FileOutputStream fs=new FileOutputStream( "c://测试//copyFile.txt"); byte[]  buffer =new  byte[1444]; int length; while ((byteread=inStream.read(buffer))!=-1)  {    out.println("<DT><B>"+byteread+"</B></DT>");    bytesum+=byteread;    out.println(bytesum);    fs.write(buffer,0,byteread);  } inStream.close(); %>   整个文件夹拷贝 <%@ page contentType="text/html;charset=gb2312"%> <%@ page import="java.io.*" %> <%String url1="C:/aaa";   String url2="d:/java/";   (new File(url2)).mkdirs();  File[] file=(new File(url1)).listFiles();  for(int i=0;i<file.length;i++){   if(file[i].isFile()){    file[i].toString();    FileInputStream input=new FileInputStream(file[i]);    FileOutputStream output=new FileOutputStream(url2+"/"+(file[i].getName()).toString());    byte[] b=new byte[1024*5];     int len;     while((len=input.read(b))!=-1){     output.write(b,0,len);     }     output.flush();     output.close();     input.close();   }  } %>   文件下载 <%@ page contentType="text/html; charset=gb2312"%> <%@ page import="java.io.*" %> <%   String fileName = "newFile.txt".toString();   //读到流中   InputStream inStream=new FileInputStream("c://测试//newFile.txt");   //设置输出的格式   response.reset();   response.setContentType("text/plain");   response.addHeader("Content-Disposition","attachment; filename=/"" + fileName + "/"");   //循环取出流中的数据   byte[] b = new byte[100];   int len;   ServletOutputStream outStream = response.getOutputStream();     while((len=inStream.read(b)) >0)   outStream.write(b,0,len);   outStream.flush();   outStream.close();   inStream.close(); %>   数据库字段中的文件下载 <%@ page contentType="text/html;charset=gb2312"%> <%@ page import="java.util.*,java.sql.*,java.io.*"%> <%     String id = request.getParameter("id");     if(id==null)     {   throw new Exception ("没有找到图片");     }     else     {        try        { com.gzrealmap.lib.jdbc.JDBCUtil  SqlBean= com.gzrealmap.lib.jdbc.JDBCUtil.getInstance();                SqlBean.connect();                String sql = "select * from innernews where id = '"+79+"'";                ResultSet rs = SqlBean.queryforUpdate(sql);                rs.next();                //String fileNamedb = rs.getString("imageName");                String file= rs.getString("acc");                //String fileName = new String(fileNamedb.getBytes(),"iso-8859-1");                String fileName = "a.jpg";                 response.setHeader("Content-Disposition",  "inline; filename=/"" + fileName + "/"");                    String filter = fileName.substring(fileName.lastIndexOf("."));                               if(filter.equals(".txt"))                {                    response.setContentType("text/plain");                }                else if(filter.equals(".doc")||filter.equals(".dot"))                {                    response.setContentType("application/msword");                }                else                {                  response.setContentType("image/jpeg;charset=GB2312");                }                ServletOutputStream o = response.getOutputStream();                //o.write(file);                out.println(file);                //o.flush();                //o.close();                SqlBean.disconnect();        }         catch(Exception ex)        {            out.println(ex.getMessage());        }     }   %>   把网页保存成文件<%@ page contentType="text/html;charset=gb2312"%> <%@ page import="java.text.*,java.util.*,java.net.*,java.io.*"%> <%  URL stdURL = null;  BufferedReader stdIn = null;  PrintWriter stdOut = null;  try {   stdURL = new URL("http://www.163.com");  }  catch (MalformedURLException e) {    throw e;  }   try {     //将字节流转变成为字符流     stdIn = new BufferedReader(new InputStreamReader(stdURL.openStream()));     String theFileName = "c://测试//163.html";     stdOut = new PrintWriter(new BufferedWriter(new FileWriter(theFileName.toString())));  }  catch (IOException e) {  }    /***把URL指定的页面以流的形式读出，写成指定的文件***/  try {     String strHtml = "";    while((strHtml = stdIn.readLine())!=null) {    stdOut.println(strHtml);    }  }  catch (IOException e) {    throw e;  }  finally {      try {      if(stdIn != null)        stdIn.close();      if(stdOut != null)        stdOut.close();        }    catch (Exception e) {      System.out.println(e);    }  } %>   直接下载网上的文件 <%@ page contentType="text/html;charset=gb2312"%> <%@ page import="java.io.*"%> <%@ page import="java.net.*"%> <%   int bytesum=0;   int byteread=0;   URL url = new URL("http://pimg.163.com/sms/micheal/logo.gif");   URLConnection conn = url.openConnection();   InputStream inStream = conn.getInputStream();     /**   String theFileName = "c:/测试/logo.gif";   theFileName = theFileName.toString();   File myFilePath=new File(theFileName);   if(!myFilePath.exists())   myFilePath.createNewFile();   **/     FileOutputStream fs=new FileOutputStream("c:/测试/logo2.gif");   byte[]  buffer =new  byte[1444];     while ((byteread=inStream.read(buffer))!=-1)     {        out.println("<DT><B>"+byteread+"</B></DT>");        bytesum+=byteread;        //System.out.println(bytesum);        fs.write(buffer,0,byteread);      } %>   按行读文件 <%@ page contentType="text/html; charset=gb2312" %> <%@ page import="java.io.*" %> <% FileReader myFileReader=new FileReader("c:/哈哈.txt"); BufferedReader myBufferedReader=new BufferedReader(myFileReader); String myString=null; String resultString=new String(); while((myString=myBufferedReader.readLine())!=null) { resultString=resultString+myString+"<br>"; } out.println(resultString); myFileReader.close(); %>   对word文档的处理（上传与下载）<%@ page contentType="application/msword" %> <!-- 以上这行设定本网页为excel格式的网页 --> <%    response.setHeader("Content-disposition","inline; filename=test1.doc"); //线上浏览方式   // response.setHeader("Content-disposition","attachment; filename=test1.doc");//下载方式    //以上这行设定传送到前端浏览器时的档名为test1.doc    //就是靠这一行，让前端浏览器以为接收到一个word档 %> //然后输出动态内容就可以得到一个word文档了   1,打开： 1）文件头上加：<%@ page  contentType="application/msword"%>  xml文件里： <mime-mapping>         <extension>doc</extension>         <mime-type>application/msword</mime-type> </mime-mapping> 2）可以用js,以下代码来自引用： <%@ page contentType="text/html;charset=gb2312" import= "java.io.*"%> <HTML> <script> var wrd=new ActiveXObject("Word.Application") wrd.visible=true alert("您的"+wrd.Application.Caption+"安装路径为：/n"+wrd.Application.Path+"/n版本号是："+wrd.Application.version+"/n注册使用者是："+wrd.Application.UserName) wrd.Documents.Add() //wrd.Documents.Open("c://exam.doc") wrd.Selection.TypeText("This is some text.") wrd.Application.Activate() wrd.ActiveDocument.SaveAs("c://exam111.doc") wrd=null </script> </HTML>   2，下载： <%@ page contentType="text/html;charset=gb2312" import= "java.io.*"%> <%// 得到文件名字和路径   String filename = "jsp.doc";   String filepath = "C://";     // 设置响应头和下载保存的文件名   response.setContentType("APPLICATION/OCTET-STREAM");   response.setHeader("Content-Disposition","attachment; filename=/"" + filename + "/"");     // 打开指定文件的流信息   java.io.FileInputStream fileInputStream = new java.io.FileInputStream(filepath + filename);   //FileOutputStream out  = new FileOutputStream(filepath+"测试//" + filename);   // 写出流信息   int i;   while ((i=fileInputStream.read()) != -1) {    out.write(i);   }   fileInputStream.close();   out.close();  %>