Fourteen weeks learning Summary & Simple Notepad

Learning Summary:
a, JDBC:
1.JDBC provided in a platform-independent standard database operations interfaces and classes, as long as the support of java database vendors, provided the database can use JDBC to operate.
2.JDBC primary action classes and interfaces:

3.JDBC steps:
(1) load the driver: driver has generated the respective database provider.
(2) connect to the database: To provide a connection path connection, a user name and password.
(3) Example of Operation: Statement or PreparedStatement objects instantiated by the connection object.
(4) Operation databases: Statement PreparedStatemen operation or, if the query, the query result that all ResultSet reception.

Two, MySQL database: It is a small relational database management systems.
Installation and configuration:

常用命令：
连接MySQL数据库：mysql -u用户名 -p密码
创建数据库：CREATE DATABASE 数据库名称
删除数据库：DROP DATABASE 数据库名称
使用数据库:USE 数据库名称
创建数据库表：
CREATE TABLE 表名称（
    字段名称1    字段类型[DEFAULT 默认值][约束]，
    字段名称2    字段类型[DEFAULT 默认值][约束]，
    ...，
    字段名称n    字段类型[DEFAULT 默认值][约束] 
）
删除数据库表：DROP TABLE 表名称；
查看表结构：DESC 表名称；
查看数据库信息：
查看全部数据库：SHOW ADTABASES；
查看一个数据库的全部表：SHOW TABLES；

Experimental: notepad
implementation code:

package jishi;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;

import javax.swing.*;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;



public class Notepad implements ActionListener {
    JFrame frame;
    JMenuBar bar;
    JMenu fileMenu,editMenu;
    JMenuItem newItem,openItem,saveItem,closeItem;
    ImageIcon newIcon,openIcon,saveIcon,closeIcon;
    JScrollPane scroll;
    JTextArea area;
    JFileChooser chooser;
    File file;
    
    public Notepad(){
        frame = new JFrame("记事本");
        bar = new JMenuBar();
        fileMenu = new JMenu("文件（F）");
        editMenu = new JMenu("编辑（E）");
        area = new JTextArea();
        scroll = new JScrollPane(area);
        
        newItem = new JMenuItem("新建（N）",newIcon);
        openItem = new JMenuItem("打开（O）",newIcon);
        saveItem = new JMenuItem("保存（S）",newIcon);
        saveItem = new JMenuItem("另存为（A)",newIcon);
        closeItem = new JMenuItem("关闭（X）",newIcon);
        JScrollPane scroll = new JScrollPane(area, ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS, ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
        
        //加监听器
        newItem.addActionListener(this);
        openItem.addActionListener(this);
        saveItem.addActionListener(this);
        saveItem.addActionListener(this);
        closeItem.addActionListener(this);
        
        fileMenu.add(newItem);
        fileMenu.add(openItem);
        fileMenu.add(saveItem);
        fileMenu.add(saveItem);
        fileMenu.add(closeItem);
        
        newItem.setMnemonic(KeyEvent.VK_N);
        newItem.setAccelerator(KeyStroke.getKeyStroke('N', java.awt.Event.CTRL_MASK));
        openItem.setMnemonic(KeyEvent.VK_D);
        openItem.setAccelerator(KeyStroke.getKeyStroke('D', java.awt.Event.CTRL_MASK));
        closeItem.setMnemonic(KeyEvent.VK_K);
        closeItem.setAccelerator(KeyStroke.getKeyStroke('K', java.awt.Event.CTRL_MASK));
        saveItem.setMnemonic(KeyEvent.VK_S);
        saveItem.setAccelerator(KeyStroke.getKeyStroke('S', java.awt.Event.CTRL_MASK));
        
        bar.add(fileMenu);
        bar.add(editMenu);
        
        frame.setJMenuBar(bar);
        frame.add(scroll);
        frame.setSize(600,400);
        frame.setVisible(true);
    }
    
    //事件监听处理
    public void actionPerformed(ActionEvent event){
        Object ob = event.getSource();
        if(ob instanceof JMenuItem){
            JMenuItem item = (JMenuItem) ob;
            if(item == newItem){
                new Notepad();
            }
            else if (item == openItem){
                chooser = new JFileChooser();
                chooser.showOpenDialog(null);
                file = chooser.getSelectedFile();
                try{
                    FileInputStream fs = new FileInputStream(file);
                    byte[] b = new byte[fs.available()];
                    fs.read(b);
                    area.append(new String(b));
                    fs.close();
                }catch(FileNotFoundException e){
                    e.printStackTrace();
                }catch(IOException e){
                    e.printStackTrace();
                }
            }
            else if (item == saveItem){
                chooser = new JFileChooser();
                chooser.showSaveDialog(null);
                file = chooser.getSelectedFile();
                try{
                    if(!file.exists()){
                        file.createNewFile();
                    }
                    
                    FileOutputStream fos = new FileOutputStream(file);
                    byte[] b = area.getText().getBytes();
                    fos.write(b);
                    fos.close();
                }catch(IOException e){
                    e.printStackTrace();
                }
            }
            else if (item == closeItem){
                System.exit(1);
            }
        }
    }
    
    
}

package jishi;

public class Demo {

    public static void main(String[] args) {
        new Notepad();

    }

}

operation result:

Fourteen weeks learning Summary & Simple Notepad

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