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在 Java 中使用 JDBC 实现增删改查的步骤如下:
1. 导入 JDBC 相关的包和类:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
2. 建立数据库连接:
String url = "jdbc:mysql://localhost:3306/mydatabase";
String username = "root";
String password = "123456";
Connection conn = null;
try { conn = DriverManager.getConnection(url, username, password);
} catch (SQLException e) {
e.printStackTrace();}
3. 创建 SQL 语句并预编译:
String sql =“SELECT * FROM mytable WHERE id = ?”;
PreparedStatement pstmt = conn.prepareStatement(sql);
4. 设置参数并执行查询:
int id = 1;
pstmt.setInt(1, id);
ResultSet rs = pstmt.executeQuery();
5. 遍历结果集:
while (rs.next()) {
int id = rs.getInt(“id”);
String name = rs.getString(“name”);
System.out.println("ID: " + id + ", Name: " + name);
}
6. 关闭数据库连接和结果集:
rs.close();
pstmt.close();
conn.close();
上述代码演示的是查询操作,若要实现增删改,只需将 SQL 语句和执行方法进行相应的修改。
– 增加数据:
String sql =“INSERT INTO mytable (id, name) VALUES (?, ?)”;
PreparedStatement pstmt = conn.prepareStatement(sql);
int id = 1;
String name =“John Doe”;
pstmt.setInt(1, id);
pstmt.setString(2, name);
int rows = pstmt.executeUpdate();
– 删除数据:
String sql =“DELETE FROM mytable WHERE id = ?”;
PreparedStatement pstmt = conn.prepareStatement(sql);
int id = 1;
pstmt.setInt(1, id);
int rows = pstmt.executeUpdate();
- 修改数据:```java
String sql = "UPDATE mytable SET name = ? WHERE id = ?";
PreparedStatement pstmt = conn.prepareStatement(sql);
int id = 1;
String name = "Jane Doe";
pstmt.setString(1, name);
pstmt.setInt(2, id);
int rows = pstmt.executeUpdate();</pre><p> 以上是使用 JDBC 实现增删改查的基本步骤,具体的操作可以根据需求进行调整和扩展。<br/></p>
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