引用传递的实际应用（一对多省份城市）

//部分setter,getter和无参构造略

class Province {
	private int pid;
	private String pname;
	private City city[];//一个省有多个城市

	public Province(int pid, String pname) {
		this.pid = pid;
		this.pname = pname;
	}

	public void setCity(City city[]) {
		this.city = city;
	}
	public City[] getCity() {
		return this.city;
	}

	public String getInfo() {
		return "省份标号: " + this.pid + " 省份名: " + this.pname;
	}
}

class City {
	private int cid;
	private String cname;
	private Province province;//一个城市属于一个省

	public City(int cid, String cname) {
		this.cid = cid;
		this.cname = cname;
	}

	public void setProvince(Province province) {
		this.province = province;
	}
	public Province getProvince() {
		return this.province;
	}

	public String getInfo() {
		return "城市名: " + this.cid + " 城市编号: " + this.cname;
	}
}

public class TestDemo {
	public static void main(String args[]) {
		//实例化对象
		City ca = new City(61,"西安");
		City cb = new City(62,"宝鸡");
		City cc = new City(63,"咸阳");
		Province province = new Province(6,"陕西");
		//设置关系
		ca.setProvince(province);
		cb.setProvince(province);
		cc.setProvince(province);
		province.setCity(new City[] {ca,cb,cc});
		//取出数据
		//一个城市找到他对应的省份
		//一个省找到他包含的城市
		System.out.println("\t -|" + ca.getProvince().getInfo());
		for (int x = 0;  x < province.getCity().length; x++) {
			System.out.println("\t -|" + province.getCity()[x].getInfo());
		}

	}
}