Java传址还是传型:丢进函数括号中…

丢进函数括号中参数的object全部都是传址的。除非是初始化在类的内部自己用new方法新建的object才是属于类本身的object：

public class MainClass {

    public static void main(String[] args) {

        SmallTester smt1 = new SmallTester();

        Shape sp1 = new Shape();

        System.out.println("new sp1.a=" + sp1.getA());

        System.out.println("new smt1.sp.a=" + smt1.getShapeA());

        sp1.setA(1);

        System.out.println("sp1.setA(1);new sp1.a=" + sp1.getA());

        System.out.println("sp1.setA(1);new smt1.sp.a=" + smt1.getShapeA());

        smt1.set(sp1);

        System.out.println("smt1.set(sp1);new sp1.a=" + sp1.getA());

        System.out.println("smt1.set(sp1);new smt1.sp.a=" + smt1.getShapeA());

        sp1.setA(2);

        System.out.println("sp1.setA(2);new sp1.a=" + sp1.getA());

        System.out.println("sp1.setA(2);new smt1.sp.a=" + smt1.getShapeA());

    }

}

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输出结果如下：

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run:

new sp1.a=0

new smt1.sp.a=0

sp1.setA(1);new sp1.a=1

sp1.setA(1);new smt1.sp.a=0

smt1.set(sp1);new sp1.a=1

smt1.set(sp1);new smt1.sp.a=1

sp1.setA(2);new sp1.a=2

sp1.setA(2);new smt1.sp.a=2

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用到的类的代码：

——————————————————————————————————————————

public class SmallTester {

    private Shape ps;

    SmallTester(){

        ps=new Shape();

    }

    public void set(Shape s){

        this.ps=s;

    }

    public int getShapeA(){

        return this.ps.getA();

    }

    public void setShapeA(int num){

        this.ps.setA(num);

    }

}

//==============================================

public class Shape {

    private int a;

    Shape(){

        a=0;

    }

    public void setA(int num){

        a=num;

    }

    public int getA(){

        return this.a;

    }

    

    public class SimpleClass {

        private Integer num = 3;

        private Boolean isGood;

        public Boolean isGoodEnough(Integer goodrange) {

            return null;

        }

        public Integer getNum() {

            return null;

        }

        public class InnerClass {

            private Integer coolNum;

            public Integer getCoolNum() {

                return null;

            }

        }

    }

}