this的二种使用方式

package com.ht.TestThis;

public class TestThisKey {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Student s1 = new Student("ht",23,"男",107);
		System.out.println(s1.name+"\t"+s1.age+"\t"+s1.sex+"\t"+s1.score);
	}

}
class Student{
	String name;
	int age;
	String sex;
	double score;
	public Student() {};
	public Student(String n,int a,String s,double d) {
		System.out.println("四参构造执行");
		name = n;
		age = a;
		sex = s;
		score = d;
	}
}

　　

package com.ht.TestThis;

public class TestThisKey {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Student s1 = new Student("ht",23,"男",107);
		Student s2 = new Student("hts",223,"男s",1207);
		System.out.println(s1.name+"\t"+s1.age+"\t"+s1.sex+"\t"+s1.score);
		System.out.println(s2.name+"\t"+s2.age+"\t"+s2.sex+"\t"+s2.score);
	}

}
class Student{
	String name;
	int age;
	String sex;
	double score;
	public Student() {};
	public Student(String name,int age,String sex,double score) {
		System.out.println("四参构造执行");
		this.name = name;
		this.age = age;
		this.sex = sex;
		this.score = score;
	}
}

　　this第二种用法：调用本类中的其他构造方法。如：this(),this(实参)

package com.ht.TestThis;

public class TestThisKey {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Student s1 = new Student("ht",23,"男",107);
		Student s2 = new Student("hts",223,"男s",1207);
		System.out.println(s1.name+"\t"+s1.age+"\t"+s1.sex+"\t"+s1.score);
		System.out.println(s2.name+"\t"+s2.age+"\t"+s2.sex+"\t"+s2.score);
	}

}
class Student{
	String name;
	int age;
	String sex;
	double score;
	public Student() {};
        public Student(String name,int age,String sex) {
              this.name= name;
	      this.age= age;
              this.sex= sex;
	}

	public Student(String name,int age,String sex,double score) {
                this(name,age,sex)//this[实参]必须在构造方法的首行 只能在构造方法，不能在普通方法中
		this.score = score;
	}
}