Encapsulated JDBC tools

encapsulation JDBC

For the convenience of adding and modifying the database , You need to encapsulate the method of connecting to the database , In this way, it will be more convenient for us to develop . Write less code , Do more . Next, I will show how to operate the database with the encapsulated tool

import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.sql.*;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Properties;

/** * @author Rhine_He * @date 2020-06-24-15:23 * @fuction JDBC encapsulation  **/
public class DBUtilUseProperties {
    
    private  static final Properties pro = new Properties();
    static Connection connection =null;
    static PreparedStatement preparedStatement =null;
    static ResultSet resultSet=null;
    static {
    
        InputStream is = DBUtilUseProperties.class.getResourceAsStream("db.propertise");
        try {
    
            pro.load(is);
            Class.forName(pro.getProperty("driver"));
        } catch (IOException | ClassNotFoundException e) {
    
                e.printStackTrace();
            }
    }
    public  static Connection getConnection(){
    
        try {
    
            connection = DriverManager.getConnection(pro.getProperty("url"),
                    pro.getProperty("user"),pro.getProperty("password"));
            return connection;
        } catch (SQLException e) {
    
            e.printStackTrace();
        }
        return null;
    }
}

test

import bean.User;
import jdbcPool.JDBCPool;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.Statement;
import java.util.List;

/** * @author Rhine_He * @date 2020-06-24-15:37 **/
public class JDBCDemoUseUtil2 {
    
    public static void main(String[] args) throws Exception {
    

        /* * Use garbage packaging JDBC operation ： */
/* Connection connection = DBUtilUseProperties.getConnection(); *//* // This method is slow , There is still SQL The danger of Injection  Statement statement = connection.createStatement(); int result = statement.executeUpdate("insert into user(userid,username,sex)values(5,' Sun Qi ',' male ')");*//* // The following methods can effectively avoid SQL The risk of Injection , To compile the first , Post run  String sql="insert into user(userid,username,sex)values(2,' Li Si ',' male ')"; PreparedStatement statement = connection.prepareStatement(sql); int result =statement.executeUpdate(); if(result != -1){ System.out.println(" Registered successfully ！"); }else { System.out.println(" Registration failed ！"); } DBUtilUseProperties.closeAll(connection,statement,null);*/
        /* * Use good packaging JDBC, You just need to use the encapsulated class to call the method , Pass on SQL And parameters , *  If it is a query, you also need to pass the class of the returned object, such as student object ：（Student.class） Premise , Write it yourself Student Entity class  */
        // Modifying data ： This method can modify and delete database data 
        DBUtilUseProperties.update("delete from user where userid>?",5);// Delete 
        DBUtilUseProperties.update("update user set username=? where userid=? "," Zhang SA ",2);// modify 
        // Query data 
        User user = DBUtilUseProperties.queryOne("select *from user where userid=?",User.class,4);// Query a piece of data 
        System.out.println(user);
        // Query multiple data 
        List<User> users = DBUtilUseProperties.queryList("select *from user", User.class, null);
        for (Object object : users) {
    
            System.out.println(object);
        }
    }
}