java使用文件流实现查看下载次数

package cn.tr.test;

import java.io.bufferedreader;

import java.io.bufferedwriter;

import java.io.file;

import java.io.fileinputstream;

import java.io.filenotfoundexception;

import java.io.fileoutputstream;

import java.io.filereader;

import java.io.filewriter;

import java.io.ioexception;

import java.io.inputstream;

import java.io.outputstream;

import java.io.reader;

import java.io.writer;

public class testdemo {

   private static int in ;

   private static file file;

   public static void main(string[] args) {

     fun2();

   }

   public static void fun(){

     /** 初始化文件中的值为0*/

     try {

       outputstream out = new fileoutputstream(file);

       string str = "00" ;

       out.write(str.getbytes());

       out.close();

     } catch (filenotfoundexception e) {

       e.printstacktrace();

     } catch (ioexception e) {

       // todo auto-generated catch block

       e.printstacktrace();

     }

   }

   public static void fun2() {

     file= new file( "d:/test/d.txt" );

     if (!file.exists()) {

       try {

         file.createnewfile();

       } catch (ioexception e) {

         // todo auto-generated catch block

         e.printstacktrace();

       }

     }

     try {

       /** 读取文件中的内容 */

       if (file.exists()&&file.length()== 0 ) {

         fun();

       }

       inputstream is = new fileinputstream(file);

       byte b[] = new byte [( int ) file.length()];

       for ( int i = 0 ; i < b.length; i++) {

         // 值字节在0-255 范围之内是作为int 来返回的

         b[i] = ( byte ) is.read();

       }

       in =integer.parseint( new string(b));

       in++;

       system.out.println( "读出来的" +in);

       /**再写入到文件中 */

       outputstream out = new fileoutputstream(file);

       string str = string.valueof(in);

       byte [] bytes = str.getbytes();

       for ( int i = 0 ; i < bytes.length; i++) {

         out.write(bytes[i]);  // 一个字节一个字节的写入

       }

       is.close();

       out.close();

       system.out.println( "写入的" +in);

     } catch (filenotfoundexception e) {

       e.printstacktrace();

     } catch (ioexception e) {

       e.printstacktrace();

     }

   }

   public static void fun3(){

     file= new file( "d:/test/d.txt" );

     if (!file.exists()) {

       try {

         file.createnewfile();

       } catch (ioexception e) {

         // todo auto-generated catch block

         e.printstacktrace();

       }

     }

     /** 先读出来*/

     try {

       if (file.exists()&&file.length()== 0 ) {

         fun();

       }

       reader reader = new filereader(file);

       char [] c = new char [( int )file.length()];

       int temp = 0 ;

       int len = 0 ;

       while ((temp=reader.read()) != - 1 ){

         c[len]=( char )temp;

         len++;

       }

       reader.close();

       system.out.println( "初始值" + new string(c, 0 ,len));

       in =integer.parseint( new string(c, 0 ,len));

       in++;

       system.out.println( "下载一次：" +in);

     /** 再写进去*/

       writer writer = new filewriter(file);

       writer.write(in+ "" );

       writer.close();

       system.out.println( "再写进去：" +in);

     } catch (filenotfoundexception e) {

       // todo auto-generated catch block

       e.printstacktrace();

     } catch (ioexception e) {

       // todo auto-generated catch block

       e.printstacktrace();

     }

   }

   public static void fun4(){

     reader reader;

     writer writer;

     file= new file( "d:/test/d.txt" );

     if (!file.exists()) {

       try {

         file.createnewfile();

       } catch (ioexception e) {

         // todo auto-generated catch block

         e.printstacktrace();

       }

     }

     try {

       if (file.exists()&&file.length()== 0 ) {

         fun();

       }

       /** 读出来*/

       reader = new filereader(file);

       bufferedreader br = new bufferedreader(reader);

       char [] c = new char [( int )file.length()];

       int len = 0 ;

       int temp = 0 ;

       while ((temp=br.read())!= - 1 ){

         c[len]=( char )temp;

         len++;

       }

       in =integer.parseint( new string(c, 0 , len));

       in++;

       system.out.println( "读出来：" + in);

       /** 写进去*/

       writer = new filewriter(file);

       bufferedwriter bw = new bufferedwriter(writer);

       bw.write(in+ "" );

       system.out.println( "写进去：" +in);

       br.close();

       bw.close();

     } catch (filenotfoundexception e) {

       // todo auto-generated catch block

       e.printstacktrace();

     } catch (ioexception e) {

       // todo auto-generated catch block

       e.printstacktrace();

     }

   } 

}