Java学习笔记（二）不定时更新

Java语言画图

package cn.witksy.dev;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

/**
 * Author: Alfred
 * Created: 2015/5/7
 */
public class Main {

    public void run() {
        BufferedImage bufferedImage = new BufferedImage(100,50,BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2 = bufferedImage.createGraphics();
        g2.setColor(Color.red);
        g2.fillRect(0,0,5,5);
        g2.setColor(Color.blue);
        g2.fillRect(10,20,5,5);
        File outputFile = new File("D:\\dev\\java\\workspace\\draw2dtest\\test.png");
        try {
            ImageIO.write(bufferedImage, "png", outputFile);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        new Main().run();
    }
}

 不循环，直接打印List元素

 

[12.3, 1.3, 10.3]

 

 

<span style="font-size:14px;">打印一个数组中的所有的元素:
1、使用for循环打印
2、将数组转化为有序的List打印出来
package com.inc.test;
 
import java.util.Arrays;
 
public class Test {
 public static void main(String[] args) {
  String names[] = { "Georgianna", "Tenn", "Simon", "Tom" };
  System.out.println(Arrays.asList(names));
 }
}
 

</span>

 

 

 

命令行运行jar 并传参数

博客分类：

• Java原创

Java 

Java代码  

1. public class Test  
2. {  
3.     public static void main(String[] args) {  
4.         String str = args[0];  
5.         System.out.println(str);  
6.     }  
7. }  

2.javac Test.java

3.jar cvf test.jar Test.class

//更新manifest.mf 将自己写的manifest.mf 放到Test.class目录
内容为 Main-Class: Test注意回车

4.jar umf MANIFEST.MF test.jar

5.java -jar test.jar 你的参数