字符串的基本运算

比较字符串、字符串前后缀、查找字符串、提取字符串、字符串转换

import  java.awt.*;
import java.applet.*;
public class StringDemo extends Applet{
    String str1="student";
    String str2=new String("china");
    char a[]={'t','e','a','c','h','e','r'};
    String str3=new String(a);
    String str4=new String(a,2,4);
    byte b[]={97,98,99,100,101};
    String str5=new String(b,0);
    public void init(){}
    public void paint(Graphics g){
        g.drawString("str1="+str1, 20, 20);
        g.drawString("str2="+str2, 20, 40);
        g.drawString("str3="+str3, 20, 60);
        g.drawString("str4="+str4, 20, 80);
        g.drawString("str5="+str5, 20, 100);
        g.drawString("str1的长度"+str1.length(), 20, 120);
        g.drawString("str2的第二个字符为:"+str2.charAt(1), 20, 140);
        g.drawString("str2转化成为大写:"+str2.toUpperCase(), 20, 160);
        g.drawString(""ch"在str3中的位置为:"+str3.indexOf("ch"), 20, 180);
        g.drawString("str4的前缀与"ac"比较的结果为:"+str4.startsWith("ac"), 20, 200);
        g.drawString("str5的第二个位置开始长度为2的子串为:"+str5.substring(1,3), 20, 220);
    }
}