java中講講PrintStream的用法

PrintStream的用法 
馬克-to-win：從學(xué)java第一天，我們就經(jīng)常用到System.out.println()，實(shí)際上查閱文檔可知，System.out就是Sun 編的一個(gè)PrintStream的實(shí)例對(duì)象。PrintStream顧名思義，Sun編它，就是用來打印的，以各種各樣的格式，打印各種各樣的數(shù)據(jù)，（boolean，char，double，float）。下面的例子就介紹了println(int x)，print（String）和print(char c)的用法。馬克- to-win：馬克 java社區(qū)：防盜版實(shí)名手機(jī)尾號(hào)： 73203。





例：1.2.1

import java.io.*;
public class TestMark_to_win {
    public static void main(String args[]) throws Exception {
        byte inp[] = new byte[3];
        inp[0] = 97;inp[1] = 98;inp[2] = 99;
        for (int i = 0; i < 3; i++) {
            /*there is no such method as println(Byte x), only sun. have the
following public void println(int x) if you want to print out
"a", use System.out.println((char)inp[i]);*/
            System.out.println(inp[i]);
        }

        for (int i = 0; i < 3; i++) {
/*public void print(char c)Print a character.*/
            System.out.println((char) inp[i]);
        }
        char c='z';
        System.out.println(c);
        String s="我們是good123";
        System.out.println(s);
        double d=3.14;
        System.out.println(d);
    }
}
      



結(jié)果是：
97
98
99
a
b
c
z
我們是good123
3.14





例：1.2.2

import java.io.*;
public class TestMark_to_win {
    public static void main(String args[]) throws Exception {
        String m = "qi hello bye97我們";
        FileOutputStream f2 = new FileOutputStream("i:/4.txt");
        PrintStream ps = new PrintStream(f2);
        /*void println(String x) Print a String and then terminate the line.
*/
        ps.println(m);
        /*Close the stream. This is done by flushing the stream and then
closing the underlying output stream. Close the stream.
the close statement can be commented out, still things can be print to
the file, but for the writer's example---ReaderWriter.java, you must
use close , otherwise nothing can be printed out to the file, because
reader's close is not the same as stream's close.*/
        char c='z';
        ps.println(c);
        byte b=97;
        ps.println(b);
        double d=3.14;
        ps.println(d);
        ps.close();
    }
}
輸出的結(jié)果是：
在4.txt文件中我們寫入了：
qi hello bye97我們
z
97
3.14