java学习之联接Mysql

java 学习之连接 Mysql 首先导入 mysql-connector-java-5.1.10-bin.ja 下载地址： http://download.csdn.net/detail/u014112584/7359185 鼠标放在项目上，右击选择Properties-----Java Build Path ------Add External JARS 测试代码： import java.sql.Connec

首先导入mysql-connector-java-5.1.10-bin.ja

下载地址：http://download.csdn.net/detail/u014112584/7359185

鼠标放在项目上，右击选择Properties----->Java Build Path ------>Add External JARS

测试代码：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import com.mysql.jdbc.PreparedStatement;
import com.mysql.jdbc.Statement;
public class MysqlTest {
static String drivername="com.mysql.jdbc.Driver";
    static String url="jdbc:mysql://localhost:3306/expression";//指向数据源
    static String username="root";
    static String password="";
    static java.sql.Statement stmt=null;
    static ResultSet re=null;
    static Connection conn=null;
    static PreparedStatement pstm=null;
    /*
     * 构造函数进行初始化
     */
    public MysqlTest(){
    
try{
    
Class.forName(drivername);//将驱动加载到运行环境中，加载的时候，驱动会自动向DriverManager完成注册
    
System.out.println("创建驱动成功");
    
}catch(ClassNotFoundException e){
    
e.printStackTrace();
    
}
    }
    /*
     * 获取连接
     */
    public static Connection getConnection(){
   
 conn=null;
   
try{
   
conn=(Connection)DriverManager.getConnection(url, username, password);//有了驱动和连接地址后，需要使用DriverManager来获取连接
   
System.out.println("连接数据库成功！");
   
}catch(SQLException e){
   
e.printStackTrace();
   
}
   
return conn;
   }
    /**
     * 关闭连接
     * @param args
     */
    public static void free(ResultSet rs,Connection conn,java.sql.Statement stmt2){
    
if(rs!=null){
    
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
System.out.println("关闭ResultSet失败！");
e.printStackTrace();
}finally{
if(conn!=null){
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
System.out.println("关闭Connection失败！");
e.printStackTrace();
}finally{
if(stmt2!=null){
try {
stmt2.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
   System.out.println("关闭Statement失败！");
e.printStackTrace();
}
}
}
}
}
    
}
    }
    public static void main(String[]args){
    
MysqlTest.getConnection();
    
try {
stmt=conn.createStatement();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
re=stmt.executeQuery("select * from data");
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
int i=1;
try {
while(re.next()){
System.out.println(i++);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
free(re,conn,stmt);
System.out.println("OK");
    }
}