java.io的日常用法

xiaoxiao2021-03-01  18

[size=medium][color=violet][size=small] <%@ page contentType="text/html;charset=gb2312"%> <% String filePath="c:/aaa/"; filePath=filePath.toString();//中文转换 java.io.File myFilePath=new java.io.File(filePath); if(!myFilePath.exists()) myFilePath.mkdir(); %> 2。新建文件 <%@ page contentType="text/html;charset=gb2312"%> <%@ page import="java.io.*" %> <% String filePath="c:/哈哈.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 strContent = "中文测试".toString(); myFile.println(strContent); resultFile.close(); %> 3。删除文件 <%@ page contentType="text/html;charset=gb2312"%> <% String filePath="c:/支出证明单.xls"; filePath=filePath.toString(); java.io.File myDelFile=new java.io.File(filePath); myDelFile.delete(); %> 4。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:/aaa.doc"); FileOutputStream fs=new FileOutputStream( "d:/aaa.doc");byte[] buffer =new byte[1444]; int length; while ((byteread=inStream.read(buffer))!=-1) { out.println("<DT><B>"+byteread+"</B></DT>"); bytesum+=byteread; System.out.println(bytesum); fs.write(buffer,0,byteread); } inStream.close(); %> 5。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.isFile()){ file.toString(); FileInputStream input=new FileInputStream(file); FileOutputStream output=new FileOutputStream(url2+"/"+(file.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(); } } %> 6。文件下载 <%@ page contentType="text/html; charset=gb2312" %> <%@ page import="java.io.*" %> <% String fileName = "zsc104.swf".toString(); //读到流中 InputStream inStream=new FileInputStream("c:/zsc104.swf"); //设置输出的格式 response.reset(); response.setContentType("bin"); response.addHeader("Content-Disposition","attachment; filename="" + fileName + """); //循环取出流中的数据 byte[] b = new byte[100]; int len; while((len=inStream.read(b)) >0) response.getOutputStream().write(b,0,len); inStream.close(); %> 7。数据库字段中的文件下载 <%@ page contentType="text/html; charset=gb2312" %> <%@ page import="java.sql.*"%> <%@ page import="java.lang.*" %> <%@ page import="java.io.*" %> <%@ page import="com.jspsmart.upload.*" %> <%@ page import="DBstep.iDBManager2000.*"%> <% int bytesum=0; int byteread=0; //打开数据库 ResultSet result=null; String Sql=null; PreparedStatement prestmt=null; DBstep.iDBManager2000 DbaObj=new DBstep.iDBManager2000(); DbaObj.OpenConnection(); //取得数据库中的数据 Sql="select * from t_local_zhongzhuan "; result=DbaObj.ExecuteQuery(Sql); result.next(); file://将数据库中的数据读到流中 InputStream inStream=result.getBinaryStream("content"); FileOutputStream fs=new FileOutputStream( "c:/dffdsafd.doc"); byte[] buffer =new byte[1444]; int length; while ((byteread=inStream.read(buffer))!=-1) { out.println("<DT><B>"+byteread+"</B></DT>"); bytesum+=byteread; System.out.println(bytesum); fs.write(buffer,0,byteread); } %> 8。把网页保存成文件 <%@ page import="java.text.*"%> <%@ page import="java.util.*"%> <%@ page import="java.io.*"%> <%@ page import="java.net.*"%> <% URL stdURL = null; BufferedReader stdIn = null; PrintWriter stdOut = null; try { stdURL = new URL("http://www.163.com"); } catch (MalformedURLException e) { throw e; } try { stdIn = new BufferedReader(new InputStreamReader(stdURL.openStream())); stdOut = new PrintWriter(new BufferedWriter(new FileWriter("c:/163.html"))); } 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); } } %> 9。直接下载网上的文件 <%@ 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(); FileOutputStream fs=new FileOutputStream( "c:/abc.gif"); byte[] buffer =new byte[1444]; int length; while ((byteread=inStream.read(buffer))!=-1) { out.println("<DT><B>"+byteread+"</B></DT>"); bytesum+=byteread; System.out.println(bytesum); fs.write(buffer,0,byteread); } %> [/size][/color][/size]
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