package rpgGenerateor;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Scanner;


/**
 * 
 * @author Administrator
 *
 */
public class RPG {
	PreparedStatement psql;
	boolean flag=false;		
	Conn conn = new Conn();
    Connection connection = null; 
 

    
	
	
	public void printout(String type,String name) throws Exception{
		boolean flag=false;		
		Conn conn = new Conn();
        Connection connection = null;  
        connection = conn.getCon();     
        connection = conn.getCon();     
        String sql="select * from "+type+" where name=?";
        psql=connection.prepareStatement(sql);	
        

		psql.setString(1, name);
		ResultSet rs = psql.executeQuery();
		while(rs.next()) {
			String names=rs.getString("name");
			int speed=rs.getInt("speed");
			int power=rs.getInt("power");
			int stamina=rs.getInt("stamina");
			int wit=rs.getInt("wit");
			System.out.println("    速度:"+speed+"    力量:"+power+"    耐力:"+stamina+"    智力:"+wit);
		}
		
		psql.close();
		connection.close();
  
	}
	public void people() throws Exception {

        System.out.println("請選擇人物:劉備/關羽/張飛/諸葛亮");		
        
        
		Scanner scan2=new Scanner(System.in);
		String people;
		while(flag==false) {
			people=scan2.next();
			if(people.equals("劉備")) {
				flag=true;
				System.out.print("姓名:劉備");
				printout("people","liubei");

				
			}
			else if(people.equals("關羽")) {
				flag=true;
				System.out.print("姓名:關羽");
				printout("people","guanyu");
			}
			else if(people.equals("張飛")) {
				flag=true;
				System.out.print("姓名,張飛");
				printout("people","zhangfei");
			}
			else if(people.equals("諸葛亮")) {
				flag=true;
				System.out.print("姓名:諸葛亮");
				printout("people","zhugeliang");
			}
			else {
				System.out.println("人物不存在,請正確輸入");	
			}
		}
		scan2.close();


	}
	
	
	
	
	
	
	public void animal() throws Exception{
		boolean flag=false;

		while(flag==false) {

			System.out.println("請選擇人物:夢奇/孫悟空/妲己");
			Scanner scan2=new Scanner(System.in);
			String people=scan2.next();
			if(people.equals("夢奇")) {

				flag=true;
				System.out.print("姓名:夢奇");
				printout("animal","mengqi");
			}
			else if(people.equals("孫悟空")) {
				flag=true;
				System.out.print("姓名:孫悟空");
				printout("animal","sunwukong");
			}
			else if(people.equals("妲己")) {
				flag=true;
				System.out.print("姓名:妲己");
				printout("animal","daji");
			}
			else {
				System.out.println("人物不存在,請正確輸入");	

			}
		}

	}
	
	
	public static void main(String[] args) throws Exception {
		boolean flag=false;
		RPG rpg=new RPG();
		
		
		Scanner scan2=new Scanner(System.in);
		System.out.println("請選擇種族:人族/獸族");
		while(flag==false) {

			String type=scan2.next();

			if(type.equals("人族")) {
				flag=true;
				try {
					rpg.people();
				} catch (Exception e) {
					e.printStackTrace();
				}
				
			}
			else if(type.equals("獸族")) {
				flag=true;
				rpg.animal();
			}
			else {
				System.out.println("種族不存在,請正確輸入");
				
			}
		}
		scan2.close();


	}
}

 

程式碼與資料庫相連線，通過讀取資料庫資訊，來實現選擇人物，輸出人物相應的資訊

1. 執行資料庫語句有兩種方式

1） 通過createStatement()成statement語句，呼叫statement物件的executeQuery(sql)執行mysql語句,一般用來執行查詢語句。

       Statement statement=connection.createStatement();
       statement.execureQuery(sql);

2）通過preparedStatement(sql)生成preparedStatement語句，呼叫物件的executeQuery()執行，可以呼叫物件的SetString()為preparedStatement語句賦值，多用於insert, update, alter等語句。

        String sql="select * from people where name=?";
        psql=connection.prepareStatement(sql);	
		psql.setString(1, name);
		ResultSet rs = psql.executeQuery();

兩者的區別： 
          用st，在動態組裝sql時，執行動態的sql語句；
          用ps時，可以更好的進行維護，避免sql語句的注入，效率更高

2. Scanner過多生成會造成nullpointerExection異常，一般主函式生成一個，主函式關閉一次，類函式生成，不用關閉
3. 資料庫連線包括4個部分 載入驅動，獲取連線物件，穿件執行語句並執行SQL，關閉jdbc並釋放資源