java实现数据库增删改查
时间: 2023-07-07 12:12:44 浏览: 56
Java通过JDBC接口可以实现数据库的增删改查。下面是一个简单的Java JDBC示例,演示如何连接到MySQL数据库并进行增删改查操作:
```java
import java.sql.*;
public class DatabaseExample {
public static void main(String[] args) {
String url = "jdbc:mysql://localhost:3306/mydatabase";
String user = "root";
String password = "mypassword";
try {
Connection conn = DriverManager.getConnection(url, user, password);
// 增加数据
PreparedStatement insertStatement = conn.prepareStatement("INSERT INTO mytable (id, name, age) VALUES (?, ?, ?)");
insertStatement.setInt(1, 1);
insertStatement.setString(2, "张三");
insertStatement.setInt(3, 20);
insertStatement.executeUpdate();
// 修改数据
PreparedStatement updateStatement = conn.prepareStatement("UPDATE mytable SET age = ? WHERE name = ?");
updateStatement.setInt(1, 21);
updateStatement.setString(2, "张三");
updateStatement.executeUpdate();
// 删除数据
PreparedStatement deleteStatement = conn.prepareStatement("DELETE FROM mytable WHERE name = ?");
deleteStatement.setString(1, "张三");
deleteStatement.executeUpdate();
// 查询数据
Statement selectStatement = conn.createStatement();
ResultSet resultSet = selectStatement.executeQuery("SELECT * FROM mytable");
while (resultSet.next()) {
int id = resultSet.getInt("id");
String name = resultSet.getString("name");
int age = resultSet.getInt("age");
System.out.println("ID: " + id + ", Name: " + name + ", Age: " + age);
}
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
```
在这个示例中,我们首先定义了数据库的URL、用户名和密码。然后使用`DriverManager.getConnection()`方法连接到数据库。接下来,我们使用`PreparedStatement`对象来执行INSERT、UPDATE和DELETE操作,并分别设置参数。最后,我们使用`Statement`对象执行SELECT查询,并遍历结果集取出每条记录的数据。最后,我们关闭了数据库连接。