TestCar.java
复制代码 代码如下:
public class TestCar {
public static void main(String[] args) {
Car c1 = new Car();
c1.color = "red";
c1.brand = "xxx";//如果这辆汽车有很多属性，这样一一赋值不是很麻烦？有没有办法一生产出来就设定它的属性（初始化）吗？有~~~看下面
}
}

class Car {
String color;
String brand;

void run() {
System.out.printf("I am running...running..running~~~~\n");
}

void showMessage() {
System.out.printf("汽车颜色:%s, 汽车品牌:%s\n", color, brand);
}
}

改进后的TestCar_EX.java
复制代码 代码如下:

public class TestCar_EX {
public static void main(String[] args) {
Car c1 = new Car("red", "xxx");
}
}

class Car {
String color;
String brand;

public Car(String color, String brand) {
this.color = color; //这里的this是这个对象的意思.第一个color是这个对象的color属性，第二个是局部变量color
this.brand = brand; //同上
}

void run() {
System.out.printf("I am running...running..running~~~~\n");
}

void showMessage() {
System.out.printf("汽车颜色:%s, 汽车品牌:%s\n", color, brand);
}
}