Question

谁能帮我解释下面每段代码的含义，详细点！

package com.mujinlei.study;

public class JavaClassStudyTest {
public JavaClassStudyTest(){

}

public JavaClassStudyTest(String s){

}

public JavaClassStudyTest(double d){

}

public JavaClassStudyTest(int i){

}

private String name;
private double salary;
public java.util.Date birthday;

public String getName(){
return name;
}

protected double getSalary(){
return salary;
}

private java.util.Date getBirthday(){
return birthday;
}

public void setName (String s){
name = s;
}
public void setSalary (double d){
salary = d;
}
public static void main(String[] args){
JavaClassStudyTest jcst = new JavaClassStudyTest();
JavaClassStudyTest jcst2 = new JavaClassStudyTest(9.99);
jcst.setName("mujinlei");
jcst2.setSalary(50000);
System.out.println(jcst.getName());
System.out.println(jcst2.getSalary());
}

}

Answer 1

package com.mujinlei.study;

public class JavaClassStudyTest {

//以下是类JavaClassStudyTest 的构造方法,当创建一个JavaClassStudyTest的实例的时候用到,如:
JavaClassStudyTest j1=new JavaClassStudyTest();
默认调用JavaClassStudyTest类的无参数构造方法-->
public JavaClassStudyTest(){
}

JavaClassStudyTest j2=new JavaClassStudyTest ("String");
调用JavaClassStudyTest类的有一个String 型参数的构造方法-->
public JavaClassStudyTest(String s){

}

JavaClassStudyTest j3=new JavaClassStudyTest (2.3);
调用JavaClassStudyTest 类的有一个double型参数的构造方法-->
public JavaClassStudyTest(double d){

}

JavaClassStudyTest j4=new JavaClassStudyTest (5);
调用JavaClassStudyTest 类的有一个int型参数的构造方法-->
public JavaClassStudyTest(int i){

}

//这是无参数的构造方法
public JavaClassStudyTest(){
}

//有一个String 型参数的构造方法
public JavaClassStudyTest(String s){

}

//有一个double型参数的构造方法
public JavaClassStudyTest(double d){

}

//有一个int 型参数的构造方法
public JavaClassStudyTest(int i){

}

private String name; //JavaClassStudyTest类的name属性,类型:String
private double salary; //JavaClassStudyTest类的salary属性,类型:double
public java.util.Date birthday; //JavaClassStudyTest类的birthday属性,类型:Date

//以下是get和set方法
因为private String name;private double salary; 都是private(私有)的.
在该类的外部不能直接访问该属性,所以要提供以下的get和set方法来获取或设置该属性的值

//获取name属性的值
public String getName(){
return name;
}

//获取salary属性的值
protected double getSalary(){
return salary;
}

//获取birthday属性的值,该方法是私有(private)的,在该类的外部不能调用该方法
private java.util.Date getBirthday(){
return birthday;
}

//设置name属性的值等于s
public void setName (String s){
name = s;
}

//设置salary属性的值等于d
public void setSalary (double d){
salary = d;
}

//main()方法,程序执行入口

public static void main(String[] args){

//创建JavaClassStudyTest 类的一个实例jcst,调用无参数构造方法
JavaClassStudyTest jcst = new JavaClassStudyTest();

//创建JavaClassStudyTest 类的一个实例jcst2,调用有一个double类型参数的构造方法
JavaClassStudyTest jcst2 = new JavaClassStudyTest(9.99);

//设置name属性的值为"mujinlei";
jcst.setName("mujinlei");
//设置salary属性的值为50000
jcst2.setSalary(50000);

//打印输出name和salary的值
jcst.getName();调用JavaClassStudyTest类实例jcst的getName()方法,返回name的值;

jcst2.getSalary(); 调用JavaClassStudyTest类实例jcst2的getSalary()方法,返回salay的值;

System.out.println(jcst.getName());
System.out.println(jcst2.getSalary());
}

}

Answer 2

package com.mujinlei.study; //这是包名

public class JavaClassStudyTest { //类声明
//以下是构造方法
public JavaClassStudyTest(){

}

public JavaClassStudyTest(String s){

}

public JavaClassStudyTest(double d){

}

public JavaClassStudyTest(int i){

}
//变量声明
private String name;
private double salary;
public java.util.Date birthday;
//变量的setter和getter
public String getName(){
return name;
}

protected double getSalary(){
return salary;
}

private java.util.Date getBirthday(){
return birthday;
}

public void setName (String s){
name = s;
}
public void setSalary (double d){
salary = d;
}
//main方法，这是程序的入口
public static void main(String[] args){
JavaClassStudyTest jcst = new JavaClassStudyTest(); //实例化
JavaClassStudyTest jcst2 = new JavaClassStudyTest(9.99); //实例化
//方法调用
jcst.setName("mujinlei");
jcst2.setSalary(50000);
System.out.println(jcst.getName()); //输出为mujinlei
System.out.println(jcst2.getSalary()); //输出为50000
}

}

Answer 3

//---------以下为JavaClassStudyTest的构造函数的重载
public JavaClassStudyTest(){

}

public JavaClassStudyTest(String s){

}

public JavaClassStudyTest(double d){

}

public JavaClassStudyTest(int i){

}
//---------以下为设置姓名 工资 和返回姓名 工资 函数
public String getName(){
return name;
}

protected double getSalary(){
return salary;
}

private java.util.Date getBirthday(){
return birthday;
}

public void setName (String s){
name = s;
}
public void setSalary (double d){
salary = d;
}