Java全面细致讲解==和equals的使用

//基本数据类型
		int i = 10;
		int j = 10;
		double d = 10.0;
		System.out.println(i == j);//true
		System.out.println(i == d);//true
		char c = 10;
		System.out.println(i == c);//true
		char c1 = 'A';
		char c2 = 65;
		System.out.println(c1 == c2);//true

   String str1 = new String("嘻嘻");
   String str2 = new String("嘻嘻");
   System.out.println(str1 == str2);//false

		int i = 10;
		boolean b = true;
//		System.out.println(i == b); 
// 报错： Operator '==' cannot be applied to 'int', 'boolean'

public boolean equals(Object obj) { return (this == obj); } 

    Person p1=new Person();
    Person p2=new Person();
    System.out.println(p1.equals(p2));//false
    //Person为自定义的类，没有对equals()进行重写
    String str1 = new String("小老师ir");
	String str2 = new String("小老师ir");
    System.out.println(str1.equals(str2));//true
    Date date1 = new Date(32432525324L);
	Date date2 = new Date(32432525324L);
	System.out.println(date1.equals(date2));//true

public class Customer {	
	private String name;
	private int age;	
@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Customer other = (Customer) obj;
		if (age != other.age)
			return false;
		if (name == null) {
			if (other.name != null)
				return false;
		} else if (!name.equals(other.name))
			return false;
		return true;
	}	
}

   int it = 65;
   float fl = 65.0f;
   System.out.println(“65和65.0f是否相等？” + (it == fl)); //true
   char ch1 = 'A'; 
   char ch2 = 12;
   System.out.println("65和'A'是否相等？" + (it == ch1));//true
   System.out.println(“12和ch2是否相等？" + (12 == ch2));//true
   String str1 = new String("hello");
   String str2 = new String("hello");
   System.out.println("str1和str2是否相等？"+ (str1 == str2));//false
   System.out.println("str1是否equals str2？"+(str1.equals(str2)));//true
   System.out.println(“hello” == new java.util.Date()); //编译不通过