java使用文件流实现查看下载次数

本文实例为大家分享了java使用文件流实现查看下载次数的具体代码，供大家参考，具体内容如下

需求：点击一个按钮的次数或者是展示文件，游戏被下载的次数

实现：开辟一个流文件，用来保存被下载的次数，然后读文件中value，点击一次value加1，再将此value保存到流文件中。
三种方法：

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();
    }

  }  

}

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