jdbc查询数据库基础

连接数据库的代码：

package chow;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

import org.apache.commons.dbcp.BasicDataSource;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;

/**
 * 基本的jdbc连接数据库
 * 
 * @author chow
 * @date 2010-7-19
 */

public class BasicJDBC {
	private static BasicDataSource dataSource;
	static {
		ApplicationContext context = new FileSystemXmlApplicationContext(
				"resource/applicationContext.xml");
		dataSource = (BasicDataSource) context.getBean("DataSource");
	}

	public static void main(String[] args) {
		Connection con = null;
		String sql = "select id from table1 where name = ?";
		try {
			// 装入数据库特定的驱动器
			Class.forName(dataSource.getDriverClassName());

			// 与数据库建立连接
			con = DriverManager.getConnection(dataSource.getUrl(), dataSource
					.getUsername(), dataSource.getPassword());

			// 使用Statement对象查询数据库
			PreparedStatement ps = con.prepareStatement(sql);
			int parameterIndex = 1;
			ps.setString(parameterIndex, "");

			//1. 执行查询，ResultSet保存查询结果
			ResultSet rs = ps.executeQuery();
			
			//2. 执行update,insert,delete语句，返回int，为影响的行数
			// ps.executeUpdate(); 
			
			while(rs.next()){
				rs.getString("columnName");
			}
			
			//最后必须关闭ResultSet和Connection
			rs.close();
			con.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

 

 

配置文件：resource目录下，applicationContext.xml文件

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

	<bean id="DataSource" destroy-method="close"
		class="org.apache.commons.dbcp.BasicDataSource">
		<property name="driverClassName" value="com.mysql.jdbc.Driver" />
		<property name="url"
			value="jdbc:mysql://" />
		<property name="username" value="" />
		<property name="password" value="" />
	</bean>

</beans>