jdbc 链接数据库工具类

package com.util;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;
/**
 * jdbc 链接数据库工具类
 * @author Administrator
 *
 */
public class DBUtils {
private static Properties props = new Properties();
static{
InputStream is = null;
is = DBUtils.class.getClassLoader().getResourceAsStream("jdbc.properties");
try {
props.load(is);
} catch (IOException e) {
e.printStackTrace();
} finally{
if(is!=null){
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
/**
* 获得连接
* @return conn
*/
public static Connection createConn(){
Connection conn = null; 
try {
Class.forName((String)props.get("driver"));
//ip地址 + 数据库名称
conn = DriverManager.getConnection(
(String)props.get("url"),
(String)props.get("username"), 
(String)props.get("password")
);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
/**
* 编译执行
* */
public static PreparedStatement getPs(Connection conn , String sql){
PreparedStatement ps = null; 
try {
ps = conn.prepareStatement(sql);
} catch (SQLException e) {
e.printStackTrace();
}
return ps ; 
}
  /**
   * 关闭连接
   * @param conn
   */
public static void close(Connection conn){
if(conn != null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public static void close(ResultSet rs){
if(rs != null){
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public static void close(PreparedStatement ps){
if(ps != null){
try {
ps.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}