DBUtil的創(chuàng)建

昵稱(chēng)17131130 2014-05-03

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DBUtil初級(jí)原始版

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package BaseDao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.sql.DataSource;
public class DBUtil {
public static Connection getConn() throws ClassNotFoundException,
SQLException {
// ORACLE的連接方式
Class.forName("oracle.jdbc.driver.OracleDriver");
String url = "jdbc:oracle:thin:@localhost:1521:orcl";
// MYSQL的連接方式
// Class.forName("com.mysql.jdbc.Driver");
// String url = "jdbc:mysql://localhost:3306/DatabaseName"; 這個(gè)沒(méi)有驗(yàn)證，錯(cuò)誤了要更正。
String user = "scott";
String password = "tiger";
Connection conn = DriverManager.getConnection(url, user, password);
return conn;
}
public static void closeConn(Connection conn, PreparedStatement ps,
ResultSet rs) throws SQLException {
if (conn != null)
conn.close();
if (rs != null)
rs.close();
if (ps != null)
ps.close();
}
}

使用DBCP 注意在main方法中不能使用在servlet中使用成功

1.先建立一個(gè)db.properties文件在src下邊

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url=jdbc\:mysql\://localhost\:3306/mr
username=root
password=root
driverName=com.mysql.jdbc.Driver

2.寫(xiě)一個(gè)監(jiān)聽(tīng)器，在tomcat啟動(dòng)的時(shí)候就把連接池就初始化

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package Listener;
import java.io.IOException;
import java.util.Properties;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import org.apache.commons.dbcp.BasicDataSource;
import java.util.Properties;
import util.DBUtil;
public class InitDataSourceListener implements ServletContextListener{
@Override
public void contextDestroyed(ServletContextEvent arg0) {
}
@Override
public void contextInitialized(ServletContextEvent arg0) {
Properties properties = new Properties();
try {
properties.load(InitDataSourceListener.class.getClassLoader().getResourceAsStream("db.properties"));
String url = properties.getProperty("url");
String username = properties.getProperty("username");
String password = properties.getProperty("password");
String driverName = properties.getProperty("driverName");
BasicDataSource basicDataSource = new BasicDataSource();
basicDataSource.setUrl(url);
basicDataSource.setUsername(username);
basicDataSource.setPassword(password);
basicDataSource.setDriverClassName(driverName);
basicDataSource.setInitialSize(30);
basicDataSource.setMaxActive(10);
basicDataSource.setMaxIdle(20); //最大閑置個(gè)數(shù)
basicDataSource.setMaxWait(1000); //最大等待時(shí)間
System.out.println(basicDataSource);
DBUtil.setDataSource(basicDataSource);
} catch (IOException e) {
e.printStackTrace();
}
}
}

3.配置web.xml

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<listener>
<listener-class>Listener.InitDataSourceListener</listener-class>
</listener>

4.再寫(xiě)DBUtil

[java] view plain copy

package util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.sql.DataSource;
public class DBUtil {
private static DataSource dataSource = null;
public static DataSource getDataSource() {
return dataSource;
}
public static Connection getConnection(){
Connection conn = null;
try {
conn = dataSource.getConnection();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
public static void setDataSource(DataSource dataSource) {
DBUtil.dataSource = dataSource;
}
public static void closeConn(Connection conn, PreparedStatement ps,
ResultSet rs) throws SQLException {
if (conn != null)
conn.close();
if (rs != null)
rs.close();
if (ps != null)
ps.close();
}
}

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