快速读写文件字符流, 坚决用 Buffered ...

1. Scanner , PrintWriter 什么的都是渣 ( 读写 50M 的文本, Scanner 慢 10 倍, PrintWriter 慢 1/4 倍 )

2. bufferedWriter : write(str); newLine(); 比 write( str+"/n" ); 快 且 移植性好

 

 

// 请自行去掉相应注释进行测试import java.io.*;import java.util.*;public class Test{public static void main(String[] args) throws IOException{long start, end;File file1 = new File("f://1.txt");File file2 = new File("f://2.txt");/*FileReader fr1 = new FileReader(file1);FileReader fr2 = new FileReader(file2);/**//*final int MAX = 5000000;FileWriter fw1 = new FileWriter(file1);FileWriter fw2 = new FileWriter(file2);/**///@@@@@@@@@@@@@@@@@@@@@@@*********************************start = System.currentTimeMillis();/*String s;BufferedReader br = new BufferedReader(fr1);while ((s = br.readLine()) != null);/**//*BufferedWriter bw = new BufferedWriter(fw1);for( int i = 0; i < MAX; i++ ){bw.write(Integer.toString(i));bw.newLine();}/**/end = System.currentTimeMillis();System.out.println("buffer用时 " + (end - start) + " 毫秒");//@@@@@@@@@@@@@@@@@@@@@@@*********************************start = System.currentTimeMillis();/*Scanner scan = new Scanner(file2);while(scan.hasNextLine())scan.nextLine();/**//*PrintWriter pw = new PrintWriter(file2);for( int i = 0; i < MAX; i++ ){pw.println(i);}/**/end = System.currentTimeMillis();//System.out.println("scan用时 " + (end - start) + " 毫秒");//System.out.println("print用时 " + (end - start) + " 毫秒");}}