package db;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class jdbcmysql {
private Connection con = null; //Database objects
//連接object
private Statement stat = null;
//執行,傳入之sql為完整字串
private ResultSet rs = null;
//結果集
private PreparedStatement pst = null;
//執行,傳入之sql為預儲之字申,需要傳入變數之位置
//先利用?來做標示
private String dropdbSQL = "DROP TABLE User ";
private String createdbSQL = "CREATE TABLE User (" +
" id INTEGER " +
" , name VARCHAR(20) " +
" , passwd VARCHAR(20))";
private String insertdbSQL = "insert into User(id,name,passwd) " +
"select ifNULL(max(id),0)+1,?,? FROM User";
private String selectSQL = "select * from User ";
public jdbcmysql()
{
try {
Class.forName("com.mysql.jdbc.Driver");
//註冊driver
con = DriverManager.getConnection(
"jdbc:mysql://localhost/test?useUnicode=true&characterEncoding=Big5",
"","");
//取得connection
//jdbc:mysql://localhost/test?useUnicode=true&characterEncoding=Big5
//localhost是主機名,test是database名
//useUnicode=true&characterEncoding=Big5使用的編碼
}
catch(ClassNotFoundException e)
{
System.out.println("DriverClassNotFound :"+e.toString());
}//有可能會產生sqlexception
catch(SQLException x) {
System.out.println("Exception :"+x.toString());
}
}
//建立table的方式
//可以看看Statement的使用方式
public void createTable()
{
try
{
stat = con.createStatement();
stat.executeUpdate(createdbSQL);
}
catch(SQLException e)
{
System.out.println("CreateDB Exception :" + e.toString());
}
finally
{
Close();
}
}
//新增資料
//可以看看PrepareStatement的使用方式
public void insertTable( String name,String passwd)
{
try
{
pst = con.prepareStatement(insertdbSQL);
pst.setString(1, name);
pst.setString(2, passwd);
pst.executeUpdate();
}
catch(SQLException e)
{
System.out.println("InsertDB Exception :" + e.toString());
}
finally
{
Close();
}
}
//刪除Table,
//跟建立table很像
public void dropTable()
{
try
{
stat = con.createStatement();
stat.executeUpdate(dropdbSQL);
}
catch(SQLException e)
{
System.out.println("DropDB Exception :" + e.toString());
}
finally
{
Close();
}
}
//查詢資料
//可以看看回傳結果集及取得資料方式
public void SelectTable()
{
try
{
stat = con.createStatement();
rs = stat.executeQuery(selectSQL);
System.out.println("ID\t\tName\t\tPASSWORD");
while(rs.next())
{
System.out.println(rs.getInt("id")+"\t\t"+
rs.getString("name")+"\t\t"+rs.getString("passwd"));
}
}
catch(SQLException e)
{
System.out.println("DropDB Exception :" + e.toString());
}
finally
{
Close();
}
}
//完整使用完資料庫後,記得要關閉所有Object
//否則在等待Timeout時,可能會有Connection poor的狀況
private void Close()
{
try
{
if(rs!=null)
{
rs.close();
rs = null;
}
if(stat!=null)
{
stat.close();
stat = null;
}
if(pst!=null)
{
pst.close();
pst = null;
}
}
catch(SQLException e)
{
System.out.println("Close Exception :" + e.toString());
}
}
public static void main(String[] args)
{
//測看看是否正常
jdbcmysql test = new jdbcmysql();
test.dropTable();
test.createTable();
test.insertTable("yku", "12356");
test.insertTable("yku2", "7890");
test.SelectTable();
}
}
電腦隨機0-9選出3個數字(數字可重複)
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