JDBC 学习笔记

心已赠人 2022-09-03 13:14 165阅读 0赞

### 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][]

[JDBC Tutorial]: https://www.tutorialspoint.com/jdbc/index.htm
[Apache Commons DBUtils - Read Query]: https://www.tutorialspoint.com/dbutils/dbutils_read_query.htm