Java中常用的数据库操作函数及使用实例

Java中常用的数据库操作函数有：

1. DriverManager类的getConnection()函数：用于建立与数据库的连接。

2. Statement类的executeQuery()函数：用于执行SQL查询语句并返回查询结果。

3. Statement类的executeUpdate()函数：用于执行SQL更新语句，如插入、修改、删除。

4. PreparedStatement类的setXXX()函数：用于设置SQL语句中的参数，其中XXX表示不同的数据类型。

5. ResultSet类的next()函数：用于判断查询结果集是否还有下一条记录。

6. ResultSet类的getString()、getInt()等函数：用于获取查询结果集中的数据。

以下是使用实例：

1. 连接数据库并执行查询语句：

String url = "jdbc:mysql://localhost:3306/test";
String user = "root";
String password = "123456";
Connection connection = DriverManager.getConnection(url, user, password);
Statement statement = connection.createStatement();
ResultSet resultSet = statement.executeQuery("SELECT * FROM student");
while (resultSet.next()) {
    String name = resultSet.getString("name");
    int age = resultSet.getInt("age");
    System.out.println("Name: " + name + ", Age: " + age);
}
resultSet.close();
statement.close();
connection.close();

2. 插入数据：

String url = "jdbc:mysql://localhost:3306/test";
String user = "root";
String password = "123456";
Connection connection = DriverManager.getConnection(url, user, password);
String sql = "INSERT INTO student (name, age) VALUES (?, ?)";
PreparedStatement statement = connection.prepareStatement(sql);
statement.setString(1, "John");
statement.setInt(2, 20);
statement.executeUpdate();
statement.close();
connection.close();

3. 修改数据：

String url = "jdbc:mysql://localhost:3306/test";
String user = "root";
String password = "123456";
Connection connection = DriverManager.getConnection(url, user, password);
String sql = "UPDATE student SET age = ? WHERE name = ?";
PreparedStatement statement = connection.prepareStatement(sql);
statement.setInt(1, 25);
statement.setString(2, "John");
statement.executeUpdate();
statement.close();
connection.close();

4. 删除数据：

String url = "jdbc:mysql://localhost:3306/test";
String user = "root";
String password = "123456";
Connection connection = DriverManager.getConnection(url, user, password);
String sql = "DELETE FROM student WHERE name = ?";
PreparedStatement statement = connection.prepareStatement(sql);
statement.setString(1, "John");
statement.executeUpdate();
statement.close();
connection.close();