java中string类的使用

package com.te.jdkapi;
/*
字符串不可变。一经初始化就不会改变
 */
public class Study_String {
    public static void main(String[] args) {
        String a = "123";
        System.out.println(a.hashCode());
        a+="123";
        String b = "123123";
        System.out.println(a.hashCode());//1450572480
        System.out.println(b.hashCode());//1450572480
        String c = new String("123123");
        System.out.println(c.hashCode()); // 字符串只要初始化就不会改变1450572480
        // 根据字符数组的内容，创建字符串对象
        char[] chars = new char[]{'1','2','3','1','2','3'};
        String d = new String(chars);
        System.out.println(d.hashCode());//1450572480
        // 根据字节数组的内容，创建字符串对象
        byte[] by = new byte[]{49,50,51,49,50,51};
        String e = new String(by);
        System.out.println(e.hashCode());//1450572480
    }
}