new String比字符串池浪费空间,为什么要用它?

对于下面程序中：ss0 = new String( "hello" );是用new()来新建对象的，存于堆中。每调用一次就会创建一个新的对象。当然从节省空间的角度来讲，肯定不如str="hello"，有童鞋一定问，那要它有什么用？当时设计编译器时，为什么要设计它？马克-to-win，那我请问你，如果在你编程序时，你还不知道字符串内容怎么办？这时就用到new String(String original)，所以，什么都有什么的用处。 

(注意不能看调试窗口里value id，eclipse的问题)

public class Test

{

    public static void main(String args[]) {

        String str, str1, ss0, ss1, ss2, ss3, ss4;

        str = "hello";

        str1 = "hello";

        ss0 = new String("hello");

        ss1 = new String("hello");

        ss2 = new String("bye");

        ss3 = new String("chi le ma");

        ss4 = new String("chi le ma");

/* ==在测内存地址是否相同，如果相同，就证明是同一个对象。== means address space is the same.str and str1 point to the same

String constant.only one place

*/

        System.out.println(str1 == str);

        System.out.println(ss1 == ss0);

/* equals 是看内容是否相等，equals means as long as value is the same, it is the same.but == mean

memory address should be the same. */

        System.out.println(ss1.equals("hello"));

        System.out.println(str1 == "hello");

        System.out.println(ss1 == "hello");

    }

}

更多请看：https://blog.csdn.net/qq_44639795/article/details/103124466