java例程练习（String类的一些常用方法）

//String类常用方法集锦

public class TestString {
public static void main(String[] args) {
String s1 = "sun java";
String s2 = "Sun Java";
//取字符
System.out.println(s1.charAt(1));//u
//长度
System.out.println(s2.length());//8
//子串位置
System.out.println(s1.indexOf("java"));//4
System.out.println(s1.indexOf("Java"));//-1
//与什么相等
System.out.println(s1.equals(s2));//false
System.out.println(s1.equalsIgnoreCase(s2));//true
//字符替换
String s = "我是程序员，我在学java";
String sr = s.replace('我', '你');
System.out.println(sr);//你是程序员，你在学java

//以什么字符串开头或结尾
String ss = "Welcome to Java World!";
System.out.println(ss.startsWith("Welcome"));//true
System.out.println(ss.endsWith("World"));//false

//转成大写或小写
String ssL = ss.toLowerCase();
String ssU = ss.toUpperCase();
System.out.println(ssL);//welcome to java world!
System.out.println(ssU);//WELCOME TO JAVA WORLD!

//截子串
String subSS = ss.substring(11);
System.out.println(subSS);//Java World!

//去掉首位空格
String st = "  sun java  ";
String sp = st.trim();
System.out.println(sp);//sun java

//valueOf静态方法求数字位数
int j = 1234567;
String sNumber = String.valueOf(j);
System.out.println("j是" + sNumber.length() + "位数");//j是7位数

//分割字符
String bd = "Mary,F,1976";
String [] bdSplit = bd.split(",");
for(int i = 0; i < bdSplit.length; i++) {
System.out.println(bdSplit[i]);
}
//		Mary
//		F
//		1976

}
}