Java字符串理解

 1 public static void main(String[] args) {
 2     String s1 = new String();
 3     String s2 = new String("Hello");
 4         
 5     //错误的创建方式
 6     //String s3 = new String(‘H‘,‘e‘,‘l‘,‘l‘,‘o‘);
 7     char[] Arr = {‘H‘,‘e‘,‘l‘,‘l‘,‘o‘};
 8     //public String(char[] value)
 9     String s3 = new String(Arr);
10         
11     //public String(char[] value, int offset, int count)
12     //offset数组起始元素下标, count表示元素个数
13     String s4 = new String(Arr,0,4);
14         
15     //特殊方式
16     String s5="Hello";
17     
18     System.out.println("s1="+s1);
19     System.out.println("s2="+s2);
20     System.out.println("s3="+s3);
21     System.out.println("s4="+s4);
22     System.out.println("s5="+s5);
23 }

1 String s1 = "Hello!";
2 String s2 = "Hello!";
3 System.out.println ( s1 == s2 );//输出true
4 
5 String s1 = "Hello!";
6 String s2 = new  String("Hello!");
7 System.out.println(s1 == s2);//输出false