小编RKP*_*RKP的帖子

请你解释下面的行为.

public class EqAndRef {

    public static void main(String[] args) {
        Integer i = 10;
        Integer j = 10;

        Double a = 10D;
        Double b = 10D;

        System.out.println(i.equals(j));
        System.out.println(i == j);


        System.out.println(a.equals(b));
        System.out.println(a == b);


    }
}

输出jdk 6

true
true
true
false

为什么a == b是假的而我= = j不是假的？

我会问一个小问题,我可能没有清楚地遵守代码.我们是否需要在这里做更多的事情.对于弹簧注射,我得到以下异常...它对于构造函数arg工作正常但不是简单的原理....

        can you point mistake here that I am committing...
        Caused by: org.springframework.beans.NotWritablePropertyException: Invalid property 'triangleType' of bean class [com.raj.spring.core.Triangle]: Bean property 'triangleType' is not writable or has an invalid setter method. Does the parameter type of the setter match the return type of the getter?

        classes ...




        package com.raj.spring.core;

        public class Triangle {

            private String triangleType;

            public Triangle(String triangleType){
                this.triangleType = triangleType;
            }
            public Triangle(){
                System.out.println("constructor");
            }
            public void drawShape() {
                System.out.println(getTriangleType()+" Shape drawn.");
            }

            /**
             * @return the …