Java连接MySQL数据库

Posted 2020-06-18 phlsheji

1 下载安装Connector/J，下载地址：http://www.mysql.com/products/connector/。Connector/J是专门针对mysql而开发的JDBC驱动程序包。
2 将安装文件夹下的mysql-connector-java-5.1.36-bin.jar加入到环境变量的classpath。或者加入到项目的Java Build Path。
3 JDBC基本编程的步骤：

• 载入驱动
  其使用的方法有Class.forName()或者
  Class.forName().newInstance()或者
  new DriverName()
• 连接数据库
  DriverManager.getConnection()
• 运行SQL语句
  Connection.CreateStatement()
Statement.executeQuery()
Statement.executeUpdate()
• 取得结果集
  while(rs.next())
• 显示数据
  将数据库中的各种类型转化为java中的类型（getXXX）方法
• 关闭
  close the resultset
close the statement
close the connection

实例：

package ms;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.ResultSet;

public class TestMySQL {
    public static void main(String[] args){
        ResultSet rs = null;
        Statement stmt = null;
        Connection conn = null;
        try{
            Class.forName("com.mysql.jdbc.Driver"); //创建该字符串标识的类的实例
            String url = "jdbc:mysql://localhost:3306/test"; //标识一个被注冊的驱动程序
            String user = "root";
            String pwd = "";
            conn = DriverManager.getConnection(url, user, pwd);
            stmt = conn.createStatement();
            String query = "select * from person where age > 18";
            rs = stmt.executeQuery(query);
            while (rs.next()){
                String id = rs.getString("id");
                String name = rs.getString(2);
                int age = rs.getInt("age");
                System.out.println(id + "\t" + name + "\t" + age);
            }
        }
        catch (ClassNotFoundException e){
            e.printStackTrace();
        }
        catch (SQLException e){
            e.printStackTrace();
        }
        finally {
            try{
                if (rs != null){
                    rs.close();
                }
                if (stmt != null){
                    stmt.close();
                }
                if (conn != null){
                    conn.close();
                }
            }
            catch (SQLException e){
                e.printStackTrace();
            }
        }
    }
}

PreparedStatement的预处理语句：

String sql = "insert into person values(?,?
,?)";
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setString(1, "005");
pstmt.setString(2, "Zhao");
pstmt.setInt(3, 18);
pstmt.executeUpdate();

statement语句的批处理：

Statement stmt = conn.createStatement();
stmt.addBatch("insert into person values(‘006‘, ‘Zeng‘, 26)");
stmt.addBatch("insert into person values(‘007‘, ‘Liu‘, 24)");
stmt.addBatch("insert into person values(‘008‘, ‘Zeng‘, 17)");
stmt.executeBatch();

PreparedStatement语句的批处理

String sql = "insert into person values(?,?,?)";
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setString(1, "006");
pstmt.setString(2, "Zeng");
pstmt.setInt(3, 26);

pstmt.setString(1, "007");
pstmt.setString(2, "Liu");
pstmt.setInt(3, 24);

pstmt.setString(1, "008");
pstmt.setString(2, "Zeng");
pstmt.setInt(3, 17);
pstmt.executeUpdate();