案例：

假设有四个人，频繁地通过海关出口，规定每次只能通过一个人，通过一个人时，将通过海关的总人次加1，同时记录该次通过人的姓名和出生地，如果出生地和名字不一致，不允许通过。

海关代码

package com.jane.service;/** * 海关入口 */public class GateWay {    private int counter = 0;    private String name = "无名";    private String address = "无地址";#     /**     * 通行     * @param name     * @param address     */    public void pass(String name, String address) {        this.counter++;        this.name = name;        this.address = address;        checkPassport();    }    /**     * 检查护照     */    private void checkPassport() {        //名字和地址匹配上才能通过        if(!this.name.equals(this.address)) {            System.out.println("禁止通行:" + "第" + this.counter + "人，姓名：" + this.name + ",来自：" + this.address);        }    }}

人的代码

package com.jane.service;/** * 人模拟线程，循环入关 */public class Person extends Thread{   private final GateWay gateWay;   private final String name;   private final String address;   public Person(GateWay gateWay, String name, String address) {       this.gateWay = gateWay;       this.name = name;       this.address = address;   }   public void run() {       System.out.println(this.name + "，开始入关");       while(true) {          this.gateWay.pass(this.name, this.address);       }   }}

启动函数

System.out.println("开始入关");        GateWay gate = new GateWay();        new Person(gate, "张三", "张三").start();        new Person(gate, "李四", "李四").start();        new Person(gate, "王五", "王五").start();        new Person(gate, "赵六", "赵六").start();