java中基本数据类型的包装类也是值传递

喜欢ヅ旅行 2022-11-10 05:42 64阅读 0赞

> java中**基本数据类型**的**包装类**也是值传递，比如：Boolean、Integer等这些包装类以及String类，他们走的是值传递，这些类可以理解成永恒不可变类。

**直接上代码和截图：**

**案例1**

![2021031617203526.png][]

public void handle(int parm1, Integer parm2, double parm3, Double parm4) {
    		System.out.println("形参parm1=" + parm1 + ",形参parm2=" + parm2 + ",形参parm3=" + parm3 + ",形参parm4=" + parm4);
    		parm1 = 12;
    		parm2 = 16;
    		parm3 = 27.98;
    		parm4 = 168.92;
    		System.out.println("形参parm1=" + parm1 + ",形参parm2=" + parm2 + ",形参parm3=" + parm3 + ",形参parm4=" + parm4);
    	}
    
    public static void main(String[] args) {
    		User user = new User();
    
    		int a = 67; //基本数据类型
    		Integer b = new Integer(23); //引用数据类型
    		
    		double c = 92.53; //基本数据类型
    		Double d = new Double(56.34); //引用数据类型
    		System.out.println("实参a=" + a + ",实参b=" + b + ",实参c=" + c + ",实d=" + d);
    		user.handle(a, b, c, d);
    		System.out.println("实参a=" + a + ",实参b=" + b + ",实参c=" + c + ",实d=" + d);
    	}

**运行结果如下：**

![20210316172309576.png][]

**案例2**

![20210316172841679.png][]

public void handle(boolean parm1, Boolean parm2) {
    		System.out.println("形参parm1=" + parm1 + ",形参parm2=" + parm2);
    		parm1 = true;
    		parm2 = true;
    		System.out.println("形参parm1=" + parm1 + ",形参parm2=" + parm2);
    	}
    
    public static void main(String[] args) {
    		User user = new User();
    		
    		boolean e = false; //基本数据类型
    		Boolean f = new Boolean(false); //引用数据类型
    		System.out.println("实参e=" + e + ",实参f=" + f);
    		user.handle(e, f);
    		System.out.println("实参e=" + e + ",实参f=" + f);
    	}

**运行结果如下：**

![2021031617292768.png][]

[2021031617203526.png]: /images/20221023/b4741dd168284cb8bb1a2f1de49b00f2.png
[20210316172309576.png]: /images/20221023/ef40e537058e4bdea169ddc13df31c47.png
[20210316172841679.png]: /images/20221023/dcebb7b074764111994edcf1902a4dde.png
[2021031617292768.png]: /images/20221023/07da871d1f7e4f0ab8c8e860f2b56496.png