数据库连接与操作：使用Java访问MySQL数据库，实现增删查操作

原创偏执的太偏执、 2024-10-08 00:06 60阅读 0赞

在Java中，我们可以使用JDBC（Java Database Connectivity）来访问MySQL数据库。以下是一个简单的示例，包括如何进行增删查操作：

1. **添加数据库连接**：
```java
import java.sql.Connection;
import java.sql.DriverManager;

public class MySQLConnection {
    private static final String DATABASE_URL = "jdbc:mysql://localhost:3306/mydatabase";
    private static final String USER = "username";
    private static final String PASSWORD = "password";

public static Connection getConnection() {
        try {
            return DriverManager.getConnection(DATABASE_URL, USER, PASSWORD));
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}
```

2. **执行操作**：
- **增加（Insert）操作**：
```java
import java.sql.Statement;

public class OperationExample {
    public static void insertData() {
        Connection connection = MySQLConnection.getConnection();
        if (connection != null) {
            try {
                Statement statement = connection.createStatement();
                // 假设你有一个数据表，名为`users`
                String sql = "INSERT INTO users (name, email) VALUES ('John Doe', 'john.doe@example.com')";

int rowsInserted = statement.executeUpdate(sql);
                if (rowsInserted > 0) {
                    System.out.println("Data inserted successfully");
                } else {
                    System.out.println("No data inserted");
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (connection != null) {
                    connection.close();
                }
            }
        }
    }

public static void main(String[] args) {
        insertData();
    }
}
```
- **查询（Select）操作**：
```java
import java.sql.ResultSet;
import java.sql.Statement;

public class QueryExample {
    public static void queryData() {
        Connection connection = MySQLConnection.getConnection();
        if (connection != null) {
            try {
                Statement statement = connection.createStatement();
                String sql = "SELECT name, email FROM users WHERE name = 'John Doe'";

ResultSet resultSet = statement.executeQuery(sql);
                while (resultSet.next()) {
                    String name = resultSet.getString("name"));
                    String email = resultSet.getString("email");

System.out.println("Name: " + name + ", Email: " + email);
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (connection != null) {
                    connection.close();
                }
            }
        }
    }

public static void main(String[] args) {
        queryData();
    }
}
```
3. **更新（Update）操作**：
```java
import java.sql.Statement;

public class UpdateExample {
    public static void updateData() {
        Connection connection = MySQLConnection.getConnection();
        if (connection != null) {
            try {
                Statement statement = connection.createStatement();
                String sql = "UPDATE users SET email = 'new.email@example.com' WHERE name = 'John Doe'";

int rowsUpdated = statement.executeUpdate(sql);
                if (rowsUpdated > 0) {
                    System.out.println("Data updated successfully");
                } else {
                    System.out.println("No data updated");
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (connection != null) {
                    connection.close();
                }
            }
        }
    }

public static void main(String[] args) {
        updateData();
    }
}
```
以上示例展示了如何使用Java访问MySQL数据库，实现增删查操作。