JDBC配置文件和工具類

db.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/news
user=root
password=admin

jdbcUtil.java

package cn.itcast.souhu.util;

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

/**
 * 工具類
 */
public class JdbcUtil {
    private static String driver;
    private static String url;
    private static String user;
    private static String password;
    private JdbcUtil(){}
    //加載src/db.properties文件
    static{
        try {
            InputStream is = JdbcUtil.class.getClassLoader().getResourceAsStream("db.properties");
            Properties props = new Properties();
            props.load(is);
            driver = props.getProperty("driver");
            url = props.getProperty("url");
            user = props.getProperty("user");
            password = props.getProperty("password");
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }
    //通過反射註冊數據庫驅動
    static{
        try {
            Class.forName(driver);
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }
    //獲取與數據庫服務器的連接
    public static Connection getConnection(){
        try {
            return DriverManager.getConnection(url,user,password);
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }
    //關閉三個數據庫連接對象
    public static void close(Connection conn){
        if(conn!=null){
            try {
                conn.close();
            } catch (Exception e) {
                e.printStackTrace();
                throw new RuntimeException(e);
            }
        }
    }
    public static void close(Statement stmt){
        if(stmt!=null){
            try {
                stmt.close();
            } catch (Exception e) {
                e.printStackTrace();
                throw new RuntimeException(e);
            }
        }
    }
    public static void close(ResultSet rs){
        if(rs!=null){
            try {
                rs.close();
            } catch (Exception e) {
                e.printStackTrace();
                throw new RuntimeException(e);
            }
        }
    }
}