学步园

1、直接以固定方式写在一个java类里进行连接，例如：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

/**
 * 封装数据库常用操作
 * @author Administrator
 *
 */
public class DbUtil {
	/**
	 * 取得Connection
	 * @return
	 */
	public static Connection getConnection(){
		Connection conn = null;
		try {
			Class.forName("oracle.jdbc.driver.OracleDriver");
			String url = "jdbc:oracle:thin:@192.168.26.3:1521:bjpowernode";
			String username = "test";
			String password = "test";
			conn = DriverManager.getConnection(url,username,password);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}catch (SQLException e) {
			e.printStackTrace();
		}
		return conn;
	}
	public static void main(String[] arges){
		System.out.println(DbUtil.getConnection());
		
	}
}

2、配合xml配置文件灵活的进行数据库连接（更容易修改）例如：

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

/**
 * 封装数据库常用操作
 * @author Administrator
 *
 */
public class DbUtil {
	/**
	 * 取得Connection
	 * @return
	 */
	public static Connection getConnection(){
		Connection conn = null;		
		try {
			JdbcConfig jdbcConfig = XmlConfigReader.getInstance().getJdbcConfig();
			Class.forName(jdbcConfig.getDriverName());
			String url = jdbcConfig.getUrl();
			String username = jdbcConfig.getUserName();
			String password = jdbcConfig.getPassword();
			conn = DriverManager.getConnection(url,username,password);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}catch (SQLException e) {
			e.printStackTrace();
		}
		return conn;
	}
	public static void main(String[] arges){
		System.out.println(DbUtil.getConnection());
		
	}
}

JdbcConfig.java类（这里面还重写了toString()方法）

/**
 * jdbc配置信息
 * @author Administrator
 *
 */
public class JdbcConfig {


	private String driverName;
	
	private String url;
	
	private String userName;
	
	private String password;

	public String getDriverName() {
		return driverName;
	}

	public void setDriverName(String driverName) {
		this.driverName = driverName;
	}

	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}

	public String getUserName() {
		return userName;
	}

	public void setUserName(String userName) {
		this.userName = userName;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}
	
	@Override
	public String toString() {
		return this.getClass().getName() + "{driverName:" + driverName + ", url:" + url + ", userName:" + userName + ", password:" + password + "}";
	}	
}

XmlConfigReader.java类（读取xml配置信息使用了单例模式）

import java.io.InputStream;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

/**
 * 采用单利模式解析sys-config.xml文件
 * @param args
 */
public class XmlConfigReader {

//	//饿汉式(预先加载)
//	private static XmlConfigReader instance = new XmlConfigReader();
//	
//	private XmlConfigReader(){
//		
//	}
//	
//	public static XmlConfigReader getInstance(){
//		return instance;
//	}
	
	//懒汉试（延迟加载lazy）
	private static XmlConfigReader instance = null;
	//保存jdbc相关配置信息
	private JdbcConfig jdbcConfig = new JdbcConfig();
	
	
	private XmlConfigReader(){
		SAXReader reader = new SAXReader();
		InputStream in = Thread.currentThread().getContextClassLoader().getResourceAsStream("sys-config.xml");
		try {
			Document doc = reader.read(in);
			//取得jdbc相关的配置
			Element driverNameElt = (Element)doc.selectObject("/config/db-info/driver-name");
			Element urlElt = (Element)doc.selectObject("/config/db-info/url");
			Element userNameElt = (Element)doc.selectObject("/config/db-info/user-name");
			Element passwordElt = (Element)doc.selectObject("/config/db-info/password");
			//设置jdbc相关的配置
			jdbcConfig.setDriverName(driverNameElt.getStringValue());
			jdbcConfig.setUrl(urlElt.getStringValue());
			jdbcConfig.setUserName(userNameElt.getStringValue());
			jdbcConfig.setPassword(passwordElt.getStringValue());
		} catch (DocumentException e) {
			e.printStackTrace();
		}
	}
	
	public static synchronized XmlConfigReader getInstance(){
		if(instance == null){
			instance = new XmlConfigReader();
		}
		return instance;
	}
	
	//返回jdbc相关配置信息
	public JdbcConfig getJdbcConfig(){
		return jdbcConfig;
	}
	
	public static void main(String[] args) {
		JdbcConfig jdbcConfig = XmlConfigReader.getInstance().getJdbcConfig();
		System.out.println(jdbcConfig);
	}
}

sys-config.xml（配置文件）

<?xml version="1.0" encoding="UTF-8"?>
<config>
	<db-info>
		<driver-name>oracle.jdbc.driver.OracleDriver</driver-name>
		<url>jdbc:oracle:thin:@192.168.26.3:1521:bjpowernode</url>
		<user-name>test</user-name>
		<password>test</password>
	</db-info>
</config>