idea通过jdbc创建一个表,有用户和密码,添加用户,删除用户,查询用户
时间: 2024-06-13 14:08:20 浏览: 14
以下是使用Java和JDBC实现对指定数据库表的增删改查操作的示例代码:
1. 加载驱动和创建连接
```java
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "password");
```
2. 创建表
```java
Statement stmt = conn.createStatement();
String sql = "CREATE TABLE users (id INT NOT NULL AUTO_INCREMENT, username VARCHAR(20) NOT NULL, password VARCHAR(20) NOT NULL, PRIMARY KEY (id))";
stmt.executeUpdate(sql);
```
3. 添加用户
```java
String username = "user1";
String password = "password1";
String sql = "INSERT INTO users (username, password) VALUES (?, ?)";
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setString(1, username);
pstmt.setString(2, password);
pstmt.executeUpdate();
```
4. 删除用户
```java
String username = "user1";
String sql = "DELETE FROM users WHERE username=?";
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setString(1, username);
pstmt.executeUpdate();
```
5. 查询用户
```java
String username = "user1";
String password = "password1";String sql = "SELECT * FROM users WHERE username=?";
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setString(1, username);
ResultSet rs = pstmt.executeQuery();
if (rs.next()) {
String dbPassword = rs.getString("password");
if (dbPassword.equals(password)) {
// 用户名和密码正确,跳转到欢迎界面
} else {
// 密码错误,弹窗提示错误类型并跳转回登录界面
}
} else {
// 用户名错误,弹窗提示错误类型并跳转回登录界面
}
```