java的String

àì夳堔傛蜴生んèń 2023-07-18 04:47 2阅读 0赞

# java的String #

#### 1. String a1="hello"和 new String(“hello”)的区别 ####

代码；

public class StringTest { 
    
        public static void main(String[] args) { 
            String h1 = "hello";
            String h2 = new String("hello");
            System.out.println("equals方法" + h1.equals(h2));
            System.out.println("h1的hashCode的值:" + h1.hashCode());
            System.out.println("h2的hashCode的值:" + h2.hashCode());
            System.out.println("内存地址是否相等：" + h1 == h2);
        }

结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTk4MDA0_size_16_color_FFFFFF_t_70]

String a1="hello";
            String a2="hello";
            String b1=new String("hello");
            /** * 。intern 方法会从字符串常量池中查询当前字符串是否存在，若不存在就会将当前字符串放入常量池中, * 若存在直接指向 */
            String b2=new String("hello").intern();//
            String b3=new String("hello");
    
            System.out.println(a1==a2);//ture
            System.out.println(a1==b1);//false
            System.out.println(a1==b2);//true
            System.out.println(b1==b2);//false
            System.out.println(b1==b3);//false

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTk4MDA0_size_16_color_FFFFFF_t_70 1]  
参加：  
https://www.cnblogs.com/aspirant/p/9193112.html  
https://www.cnblogs.com/pokid/p/10437716.html  
https://juejin.im/post/5c9441686fb9a070b153e711  
https://zhuanlan.zhihu.com/p/60370408

#### 2.String为什么要用final修饰 ####

https://cloud.tencent.com/developer/article/1334960

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMTk4MDA0_size_16_color_FFFFFF_t_70 1]: /images/20230528/70b98852fbe4467fbbc97db728953ea0.png