JDBC封装及资源文件

一、简单封装

package com.lgd.jdbc;

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

public class JDBCUtil {

    public static Connection getConn()
    {       
        try {
            Class.forName("com.mysql.jdbc.Driver");
            return DriverManager.getConnection("jdbc:mysql://localhost:3306/testjdbc","root","liguodong");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
            return null;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        }               
    }

    public static void close(Connection conn)
    {               
        if(conn!=null){
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    public static void close(Statement stat,Connection conn)
    {       
        if(stat!=null){
            try {
                stat.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

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

    public static void close(ResultSet rs, Statement stat,Connection conn)
    {
        if(rs!=null){
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

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

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

}

package com.lgd.jdbc;

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

/**
 * 使用JDBCUtil工具类简化操作
 * @author liguodong
 *
 */

public class Demo12 {
    public static void main(String[] args) {
        Connection conn = null;
        PreparedStatement  ps = null;
        ResultSet rs = null;
        try {
            conn = JDBCUtil.getConn();

            ps = conn.prepareStatement("insert into user(username) values(?)");
            ps.setString(1, "扎西娅");
            ps.executeUpdate(); 

        } catch (Exception e) {
            e.printStackTrace();
        } finally{
            JDBCUtil.close(rs, ps, conn);           
        }
    }

}

二、资源文件

/src/db.properties

mysqlDriver=com.mysql.jdbc.Driver
oracleDriver=oracle.jdbc.driver.OracleDriver
oracleURL=jdbc\:oracle\:thin\:@localhost\:1521\:database
mysqlURL=jdbc\:mysql\://localhost\:3306/testjdbc
mysqlUser=root
mysqlPwd=liguodong
oracleUser=root
oraclePwd=liguodong

---

---

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package com.lgd.jdbc;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;



public class JDBCUtil2 {

    static Properties pros = null; //可以帮助和处理资源文件中的信息

    static{//加载JDBCUtil2类的时候调用一次
        pros = new Properties();
        try {
            pros.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("db.properties"));
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    public static Connection getMysqlConn()
    {       
        try {
            Class.forName(pros.getProperty("mysqlDriver"));
            return DriverManager.getConnection(pros.getProperty("mysqlURL"),
                    pros.getProperty("mysqlUser"),pros.getProperty("mysqlPwd"));
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
            return null;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        }               
    }

    public static Connection getOracleConn()
    {       
        try {
            Class.forName(pros.getProperty("oracleDriver"));
            return DriverManager.getConnection(pros.getProperty("oracleURL"),
                    pros.getProperty("oracleUser"),pros.getProperty("oraclePwd"));
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
            return null;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        }               
    }

    public static void close(Connection conn)
    {               
        if(conn!=null){
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    public static void close(Statement stat,Connection conn)
    {       
        if(stat!=null){
            try {
                stat.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

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

    public static void close(ResultSet rs, Statement stat,Connection conn)
    {
        if(rs!=null){
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

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

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

}