java - 无法在Java中一起打印字符串和 boolean 值

Question

public class Main
{
    public static void main(String[] args) {
        final String man1="All man are created equal:27";
        final String man2="All man are created equal:"+man1.length();
        System.out.print("All man are created equal:"+man1==man2);
    }
}

为什么只打印false而不打印整个print语句。

Answer 1

由于Operator Precedence

==低于+，因此首先将评估字符串连接（+），然后评估其相等性（==）

顺序为：


+：“所有人的平等创造：” + man1 =>“所有人的平等创造：所有人平等创造：27”
==：“所有人的创造力相等：所有人的创造力相等：27” == man2 =>否
System.out.println(false)


奖励使用equals比较字符串（对象）

public static void main(String[] args) {
    final String man1 = "All man are created equal:28";
    final String man2 = "All man are created equal:" + man1.length();

    System.out.println(("All man are created equal:" + man1) == man2);
    System.out.println("All man are created equal:" + (man1 == man2));
    System.out.println("All man are created equal:" + man1.equals(man2));
}

输出量

false
All man are created equal:false
All man are created equal:true