java io 處理流，BufferdInputStream、BufferedWriter、BufferedReader

BufferdInputStream：讀取helloworld。java

helloworld.java:

 

package io;

public class HelloWorld {

    public static void main(String[] args) {
        
        System.out.println("Hello World");
    }
}

 

 

 

package io;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class TestBufferdStream {

    public static void main(String[] args) {
        try {
            FileInputStream fis = new FileInputStream("f:\\share\\j2se\\IO\\HelloWorld.java");
            BufferedInputStream bis = new BufferedInputStream(fis);
            
            int c = 0;    
            System.out.println(bis.read());
            System.out.println(bis.read());
            //在輸入流中的當前位置上作標記。
            //reset 方法的后續調用將此流重新定位在最后標記的位置上，以便后續讀取操作重新讀取相同的字節。
            bis.mark(104);
            for(int i=0;i<10 && (c=bis.read())!=-1;i++){
                System.out.print((char)c+" ");
            }
            System.out.println();
            //將此流重新定位到對此輸入流最后調用 mark 方法時的位置。 
            bis.reset();
            for(int i=0;i<10 && (c=bis.read())!=-1;i++){
                System.out.print((char)c+" ");
            }
            bis.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

BufferedWriter\BufferedReader:

例子程序：

 

package io;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class TestBufferdInputStream2 {

    public static void main(String[] args) {
        try {    
            BufferedWriter bw = new BufferedWriter(new FileWriter("f:\\share\\j2se\\IO\\dat2.txt"));
            BufferedReader br = new BufferedReader(new FileReader("f:\\share\\j2se\\IO\\dat2.txt"));
            
            String s = null;
            //寫50個隨機數到dat2.txt
            for(int i=1; i < 50; i++){
                s = String.valueOf(Math.random());
                bw.write(s);
                bw.newLine();//換行
            }
            bw.flush();
            //讀取50行隨機字符，一次讀取一行
            while((s=br.readLine()) != null){
                System.out.println(s);
            }
            bw.close();
            br.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

 

dat2.txt:

0.24435601362218273
0.07126801193316767
0.445311738285074
0.35293158421910387
0.04822819969288661
0.464188774352171
0.6905170100489313
0.8547166555962266
0.5541870091691403
0.9247856173061691
0.48488882959764723
0.5193802516020373
0.04851570819954021
0.3532430846365504
0.5913492607077712
0.7269377024915321
0.46016618867662185
0.8830446251301621
0.2703242210883656
0.07017468795157189
0.10078493531688781
0.23783445875014186
0.00409907542074428
0.9501608886342727
0.3959891143119634
0.7696311492996133
0.023352826602872856
0.9771539795955477
0.9819466949500667
0.03218300631060633
0.9869752588243724
0.8710162291479447
0.003228411938660858
0.7442323830163325
0.7688111962900284
0.3218677237396862
0.44106400125074907
0.7796821087986395
0.9387643377368098
0.31955151461514586
0.825548588820152
0.38513415381788396
0.19073290448507962
0.7895878480795029
0.741009435685509
0.16999690403089585
0.6661380207280028
0.9836458017809654
0.12065762566480698