Java定义形式及可变参数实例解析

package com.my.pac05;

/**
 * @author Summerday
 * @date 2019/12/1 15:30
 */
public class MethodTest {
  public static void main(String[] args) {
    //通过类直接调用static修饰的first()方法
    MethodTest.first();
    //MethodTest.second();错误
    //方法由static修饰，可以通过类直接调用static修饰的方法
    //创建实例对象，访问没有static修饰的普通方法
    MethodTest method = new MethodTest();
    method.second();
    //接收secondVal方法的返回值
    int secondValue = method.secondVal();
    System.out.println(secondValue);//10
    
    method.third(2);
    //接收thirdVal方法的返回值
    int thirdValue = method.thirdVal(20);
    System.out.println(thirdValue);//20
    
    method.fourth('a', 'b');
    method.fifth("hello","what's","your","name");
    System.out.println();
    method.sixth(new String[]{"hello","what's","your","name"});
  }

  //static修饰的静态方法
  public static void first(){
    System.out.println("static: no param...");
  }
  //无参数(无参无返）
  public void second() {
    System.out.println("no param..");
  }
  //无参有返
  public int secondVal(){
    return 10;
  }
  //一个参数（有参无返）
  public void third(int param1) {
    System.out.println("one param.. value is " + param1);
  }
  //有参有返
  public int thirdVal(int param1){
    return param1;
  }
  //两个参数
  public void fourth(char param1, char param2) {
    System.out.println("two params.. param1 is "
        + param1 + ",param2 is " + param2);
  }
  //多个参数1
  public void fifth(String...params){
    System.out.println("*type...param*");
    for(String param:params){
      System.out.print(param+" ");
    }
  }
  //错误：public void fifth1(String...params,int a )
  //多个参数2
  public void sixth(String[] params){
    System.out.println("*type[] param*");
    for(String param:params){
      System.out.print(param+" ");
    }
  }
}

//通过类直接调用static修饰的fourth()方法
  MethodTest.first();
//也可以通过创建的对象调用static修饰的方法
  method.first();
//static修饰的静态方法
  public static void first(){
    System.out.println("static: no param...");
}

//MethodTest.second();错误
//创建实例对象，访问没有static修饰的普通方法
  MethodTest method = new MethodTest();
  method.second();

//无static修饰的普通方法
  public void second() {
    System.out.println("no param..");
  }

//无参无返
  public void second() {
    System.out.println("no param..");
  }

 //无参有返
  public int secondVal(){
    return 10;
  }

//有参无返
  public void third(int param1) {
    System.out.println("one param.. value is " + param1);
  }

 //有参有返
  public int thirdVal(int param1){
    return param1;
  }

//多个参数2
  public void sixth(String[] params){
    System.out.println("*type[] param*");
    for(String param:params){
      System.out.print(param+" ");
    }
  }

 //多个参数1
  public void fifth(String...params){
    System.out.println("*type...param*");
    for(String param:params){
      System.out.print(param+" ");
    }
  }
  //需要在最后一个参数类型和参数名之间！！！
  //错误：public void fifth1(String...params,int a )