Java利用JDBC访问数据库的编程步骤

Java利用JDBC访问数据库的编程步骤

Java利用JDBC访问数据库的编程步骤

1）加载连接数据库的驱动程序 Class.forName("com.mysql.jdbc.Driver");

2）创建与数据源的连接

tring url ="jdbc:mysql://localhost:3306/databases"

Connection conn=DriverManager.getConnection(url,"user","Password");

3）查询数据库：创建Statement对象并执行SQL语句以返回一个ResultSet对象。

Statement stmt=conn.createStatement();

ResultSet rs=stmt.executeQuery("select * from DBTableName");

4）获得当前记录集中的某一记录的各个字段的值

String name=rs.getString("Name");

int age=rs.getInt("age");

float wage=rs.getFloat("wage");

5）关闭查询语句及与数据库的连接（注意关闭的顺序先rs再stmt最后为conn）

rs.close();

stmt.close();

con.close();

import java.sql.*;

public class WebRs {

private Connection conn=null;

private Statement stmt=null;

private ResultSet rs=null;

private ResultSetMetaData stmd=null;

public WebRs(String dri,String user,String pass,String url){

try {

Class.forName(dri);

} catch (Exception e) {

System.out.println("加载驱动异常");

}

try {

conn=DriverManager.getConnection(url,user,pass);

if(conn!=null){

stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);

}

} catch (Exception e) {

System.out.println("数据库链接失败");

}

}

public ResultSet getres(String sql){

try {

rs=stmt.executeQuery(sql);

if(rs!=null){

return rs;

}else{

return null;

}

} catch (Exception e) {

System.out.println("数据库查询失败");

}

return rs;

}

public static void main(String[] args) throws SQLException{

String driver="com.mysql.jdbc.Driver";

String url="jdbc:mysql://localhost:3306/mysql";

String sql="select * from user";

WebRs mysql=new WebRs(driver,"root","pass",url);

ResultSet rs=mysql.getres(sql);

while(rs.next()){

System.out.println(rs.getString(1));

}

}

}