Java操作SQL資料庫(JDBC)

0.引入驅動jar包

使用jdbc進行具體操作前，需要引入相關資料庫的jar包, 或者使用mave管理依賴

<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->

<dependency>

    <groupId>mysql</groupId>

    <artifactId>mysql-connector-java</artifactId>

    <version>8.0.23</version>

</dependency>

<!-- https://mvnrepository.com/artifact/org.xerial/sqlite-jdbc -->

<dependency>

    <groupId>org.xerial</groupId>

    <artifactId>sqlite-jdbc</artifactId>

    <version>3.34.0</version>

</dependency>

1.載入驅動

Class.forName(DRIVER);

2.獲取資料庫連線物件

Connection conn=DriverManager.getConnection(URL);

3.建立(預處理)語句物件

普通語句物件

Statement stmt=conn.createStatement();

預處理語句物件

PreparedStatement pstmt=conn.prepareStatement(sql);

pstmt.setXxx(int parameterIndex, Xxx x); // 引數索引從1開始

4.執行sql語句

普通語句物件執行sql

boolean b=stmt.execute(sql);

int i=stmt.executeUpdate(sql);

ResultSet resultSet=stmt.executeQuery(sql);

預處理語句物件執行sql

int i=pstmt.executeUpdate();

ResultSet resultSet=pstmt.executeQuery();

5.處理結果集

while(resultSet.next())

{

    int id=resultSet.getInt("id");

    String name=resultSet.getString("name");

}

6.關閉結果集,語句,連線

resultSet.close();

stmt.close();

conn.close();

jdbc工具類封裝

在類路徑下建立配置檔案

mysql.properties

DRIVER=com.mysql.cj.jdbc.Driver

URL=jdbc:mysql://localhost:3306/test

USER=root

PASSWORD=root

DBUtil.java

public class DBUtil

{

    private static final String URL;

    private static final String USER;

    private static final String PASSWORD;

    private DBUtil(){}

    static

    {

        // 從properties檔案中載入配置資訊

        ResourceBundle bundle=ResourceBundle.getBundle("mysql");

        String DRIVER=bundle.getString("DRIVER");

        URL=bundle.getString("URL");

        USER=bundle.getString("USER");

        PASSWORD=bundle.getString("PASSWORD");

        try

        {

            Class.forName(DRIVER);

        }

        catch(ClassNotFoundException e)

        {

            e.printStackTrace();

        }

    }

    public static Connection getConnection() throws SQLException

    {

        return DriverManager.getConnection(URL,USER,PASSWORD);

    }

}