java中讲讲PrintStream的用法

PrintStream的用法 
马克-to-win：从学java第一天，我们就经常用到System.out.println()，实际上查阅文档可知，System.out就是Sun 编的一个PrintStream的实例对象。PrintStream顾名思义，Sun编它，就是用来打印的，以各种各样的格式，打印各种各样的数据，（boolean，char，double，float）。下面的例子就介绍了println(int x)，print（String）和print(char c)的用法。马克- to-win：马克 java社区：防盗版实名手机尾号： 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="我们是good123";
        System.out.println(s);
        double d=3.14;
        System.out.println(d);
    }
}
      



结果是：
97
98
99
a
b
c
z
我们是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我们";
        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();
    }
}
输出的结果是：
在4.txt文件中我们写入了：
qi hello bye97我们
z
97
3.14