直接上代碼和截圖
public static void main(String[] args) {
String str1 = "abc";
String str2 = "abc";
String str3 = "efg";
String str4 = new String("abc");
String str5 = new String("abc");
String str6 = new String("efg");
String str7 = "efg";
System.out.println(str1 == str2);//true
System.out.println(str1 == str4);//false
System.out.println(str1 == str5);//false
System.out.println(str4 == str5);//false
System.out.println(str3 == str6);//false
System.out.println(str3 == str7);//true
System.out.println(str1 == str3);//false
}
運作結果如下:
注意:看如下代碼,看看null+null等于什麼?
System.out.println(null + null);//報錯,連編譯都通不過
String n = null;
String m = null;
System.out.println(n + m);//nullnull