jdbc连接池详解

t通过读取配置文件propertise来获取连接词的url，username,password

                ResourceBundle init = ResourceBundle.getBundle("config.demo.demo-jdbc");

String driver = init.getString("jdbc.driver");
String url = init.getString("jdbc.url");
String user = init.getString("jdbc.username");

代码：

import java.sql.Connection;

import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ResourceBundle;

public class JdbcUtil {
static Connection conn = null;        //把连接词配置成为一个单例的模式
public static Connection getConn() {
if(null == conn) {
ResourceBundle init = ResourceBundle.getBundle("config.demo.demo-jdbc");
String driver = init.getString("jdbc.driver");
String url = init.getString("jdbc.url");
String user = init.getString("jdbc.username");
String password = init.getString("jdbc.password");
try {
Class.forName(driver);
//conn = DriverManager.getConnection(url, user, password);
conn = DriverManager.getConnection(url, "root", "root");
System.out.println(conn);
} catch (Exception e) {
e.printStackTrace();
}
}
return conn;
}

//插入数据到数据库

public static void insertData(String sql) {
Connection conn = getConn();
Statement stmt = null;

try {
stmt = conn.createStatement();
stmt. execute(sql);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();

}finally{

                       //使用完statment之后要记得要关闭

if(null != stmt){
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}

}

//查询数据库

public static void main(String[] args) {

Connection conn=JdbcUtil.getConn();
//查询 
String Select = "select id,msg,time,username,app,operation,object,result,detail from startstopinfo ";
Statement st=null;
ResultSet rs=null;
try {
st = (Statement) conn.createStatement();
rs= st. executeQuery(Select);
while (rs.next()){ 
System.out.print("   "+rs.getInt(1));
System.out.print("   "+rs.getString(2));
System.out.print("   "+rs.getString(3));
System.out.print("   "+rs.getString(4));
System.out.print("   "+rs.getString(5));
System.out.print("   "+rs.getString(6));
System.out.print("   "+rs.getString(7));
System.out.print("   "+rs.getString(8));
System.out.print("   "+rs.getString(9));
System.out.println();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} 
        }
}