sql之jdbc连接数据库

package com.xs.db;

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

public class DbUtil {

    static String url ;
    static String username; 
    static String pass ;
    static String drivername ;

    static FileInputStream stream = null;
    static Properties properties = null;

    static Connection con = null;
    static PreparedStatement ps = null;
    static ResultSet rs = null;
    static {
        try {
            properties = new Properties();
            stream = new FileInputStream("dbinfo.properties");
            properties.load(stream);
            url = properties.getProperty("url");
            username = properties.getProperty("username");
            pass = properties.getProperty("pass");
            drivername = properties.getProperty("drivername");
            con = DriverManager.getConnection(url, username, pass);

            Class.forName(drivername);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            try {
                stream.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            stream = null;
        }
    }

    public Connection getConnection() {
        try {
            con = DriverManager.getConnection(url, username, pass);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return con;

    }

    /**
     * 如果只有一个sql语句，不需要考虑事务 select * from person where id=? and pass=?;
     * 则parameters的值就是(1,"123") 利用占位符惊进行查找
     * 
     * @param sql
     * @param parameters
     */
    public  void executeUpdate(String sql, String[] parameters) {

        try {
            con = getConnection();
            ps = con.prepareStatement(sql);
            if (parameters != null) {
                for (int i = 0; i < parameters.length; i++) {
                    ps.setString(i + 1, parameters[i]);
                }
            }
            ps.executeUpdate();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            // 抛出异常
            throw new RuntimeException(e.getMessage());
        } finally {
            // 关闭函数
            close(con, ps, rs);
        }

    }

    /**
     * 如果是多个sql语句的话，需要考虑事务啦
     * 
     * @param sql
     * @param parameters
     */
    public void executeUpdate2(String sql[], String[][] parameters) {

        try {
            con = getConnection();
            con.setAutoCommit(false);
            for (int i = 0; i < sql.length; i++) {
                ps = con.prepareStatement(sql[i]);
                if (parameters[i] != null) {
                    for (int j = 0; j < parameters.length; j++) {
                        ps.setString(j + 1, parameters[i][j]);
                    }
                    ps.executeUpdate();
                }
            }
            con.commit();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            throw new RuntimeException(e.getMessage());
        } finally {
            close(con, ps, rs);
        }
    }

    public void close(Connection con, Statement st, ResultSet rs) {
        if (st != null) {
            try {
                st.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            st = null;
            if (con != null) {
                try {
                    con.close();
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                con = null;
            }
            if (rs != null) {
                try {
                    rs.close();
                } catch (SQLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                rs = null;
            }
        }
    }

}