JDBC 学习笔记

Posted 2021-09-04 笑虾

JDBC 学习笔记

• 带参数查询
• 工具 commons-dbutils
• 参考资料

带参数查询

demo 所以完全没有处理异常。

package com.jerry.utilsdemo;

import java.sql.*;

public class mysqlDemo {

    static final String JDBC_DRIVER = "com.mysql.cj.jdbc.Driver";
    static final String DB_URL = "jdbc:mysql://localhost:3306/demo?useSSL=false&serverTimezone=UTC&characterEncoding=UTF-8";
    static final String USER = "root";
    static final String PASS = "root";

    public static void main(String[] args) throws Exception {
        // 注册 JDBC 驱动
        Class.forName(JDBC_DRIVER);

        // 打开链接
        Connection conn = DriverManager.getConnection(DB_URL,USER,PASS);

        // 带参查询
        PreparedStatement pstmt = conn.prepareStatement("SELECT title, content, author FROM poem where title = ?");
        pstmt.setString(1, "痴情癫");
        ResultSet rs = pstmt.executeQuery();

        // 展开结果
        while(rs.next()){
            System.out.println("title   : " + rs.getString("title"));
            System.out.println("content : " + rs.getString("content"));
            System.out.println("author  : " + rs.getString("author"));
        }

        // 释放资源
        rs.close();
        pstmt.close();
        conn.close();
    }
}

工具 commons-dbutils

• pom.xml

<dependency>
    <groupId>commons-dbutils</groupId>
    <artifactId>commons-dbutils</artifactId>
    <version>1.7</version>
</dependency>

• DBUtilsDemo.java

package com.jerry.utilsdemo;

import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.ResultSetHandler;
import org.apache.commons.dbutils.handlers.BeanHandler;

import java.sql.Connection;
import java.sql.DriverManager;

public class DBUtilsDemo {

    static final String JDBC_DRIVER = "com.mysql.cj.jdbc.Driver";
    static final String DB_URL = "jdbc:mysql://localhost:3306/demo?useSSL=false&serverTimezone=UTC&characterEncoding=UTF-8";
    static final String USER = "root";
    static final String PASS = "root";

    public static void main(String[] args) throws Exception {
        Connection conn = null;
        QueryRunner queryRunner = new QueryRunner();
        //1: 注册 JDBC 驱动
        DbUtils.loadDriver(JDBC_DRIVER);

        //2: 打开连接
        System.out.println("连接到数据库...");
        conn = DriverManager.getConnection(DB_URL, USER, PASS);

        //3: 创建返回集
        ResultSetHandler<Poem> resultHandler = new BeanHandler<Poem>(Poem.class);
        try {
            String sql = "SELECT title, content, author FROM poem WHERE title = ?";
            Poem poem = queryRunner.query(conn, sql, resultHandler, "爱云说");
            System.out.println(poem);
        } finally {
            DbUtils.close(conn);
        }
    }
}

参考资料

JDBC Tutorial
Apache Commons DBUtils - Read Query