7.2 字符串比较

demo1

public class HelloWorld {
    public static void main(String[] args){

        String strA = "mldn";// 直接赋值定义字符串
        String strB = new String("mldn");//构造方法定义字符串
        String strC = strB;// 引用传递
        System.out.println(strA == strB);//false
        System.out.println(strA == strC);//false
        System.out.println(strB == strC);//true
    }

}

demo2 通过自定义类型使用“==”

class Dept {}   // 随意定义一个空类

public class HelloWorld {
    public static void main(String[] args){

        Dept deptA = new Dept();// 开辟堆内存
        Dept deptB = new Dept();// 开辟堆内存
        Dept deptC = deptB;// 引用传递,堆内存地址相同;
        System.out.println(deptA == deptB);//false
        System.out.println(deptA == deptC);//false
        System.out.println(deptB == deptC);//true

    }

}

demo3 equals 字符串内容比较

public class HelloWorld {
    public static void main(String[] args){

        String strA = "mldn";// 直接赋值定义字符串
        String strB = new String("mldn");//构造方法定义字符串
        System.out.println(strA.equals(strB));// true 字符串内容比较
    }

}