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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