定义一个老师类，创建这个类的两个对象

public class Teacher{
    private String name;
    private int age;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public boolean equals(Object o) {
        //同一个对象，equals肯定是true
        if (this == o){
            return true;
        }
        //为null 或者类型不一样那为false
        if (o == null || getClass() != o.getClass()){
            return false;
        }
        Teacher teacher = (Teacher) o;
        //2个属性一样为true
        if (age == teacher.age && name.equals(teacher.name)){
            return true;
        }
        //其他为false
        return false;
    }

    //求u的个数
    public int countU(String value){
        int len = value.length();  //没替换u之前的字符串长度
        value = value.replaceAll("u", "");
        int len2 = value.length();  //替换u之后的字符串长度
        //2个长度相减，就知道有几个u被替换了
        return len - len2;
    }

    //获取传入英文语句中间的单词
    public String findCentreStr(String value){
        //使用空格进行切分:
        //比如：传入的value为：All roads lead to Rome
        //切分之后 strs = [All, roads, lead, to,  Rome]
        //取中间那个即可
        //这里有限制，输入的单词间只允许一个空格
        String[] strs = value.split(" ");
        int mid = strs.length / 2;  //中间值索引
        return strs[mid];
    }

    public static void main(String[] args) {
        Teacher t1 = new Teacher();
        t1.setName("zhangsan");
        t1.setAge(18);
        Teacher t2 = new Teacher();
        t2.setName("zhangsan");
        t2.setAge(18);

        System.out.println(t1.equals(t2));  //true
        System.out.println(t1.countU("good good study, day day up!")); //2
        System.out.println(t1.findCentreStr("All roads lead to Rome")); //lead

    }

}