事務(wù): 是一個完整的業(yè)務(wù)流程,可以有效的防止數(shù)據(jù)丟失

事務(wù)特性: 原子性 一致性 隔離性 持久性

使用事務(wù)的方法:

1.關(guān)閉自動提交，開啟事務(wù)：通過 connection.setAutoCommit(false) 關(guān)閉自動提交，手動控制事務(wù)。
2.提交事務(wù)：通過connection.commit() 提交事務(wù)，使所有操作生效
3.異常處理：如果發(fā)生 SQLException，捕獲異常并使用connection.rollback(); 回滾事務(wù)，確保數(shù)據(jù)一致性。

示例代碼

假設(shè)我們有兩個表：accounts 和 transactions。accounts 表存儲賬戶信息，transactions 表存儲交易記錄。

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;

public class JdbcTransactionExample {

    // 數(shù)據(jù)庫連接信息
    private static final String URL = "jdbc:mysql://localhost:3306/your_database";
    private static final String USER = "your_username";
    private static final String PASSWORD = "your_password";

    public static void main(String[] args) {
        Connection connection = null;
        PreparedStatement updateAccountStmt = null;
        PreparedStatement insertTransactionStmt = null;

        try {
            // 1. 加載數(shù)據(jù)庫驅(qū)動
            Class.forName("com.mysql.cj.jdbc.Driver");
            // 2. 建立數(shù)據(jù)庫連接
            connection = DriverManager.getConnection(URL, USER, PASSWORD);

            // 3. 關(guān)閉自動提交，開啟事務(wù)
            connection.setAutoCommit(false);

            // 4. 創(chuàng)建 PreparedStatement 對象
            String updateAccountSql = "UPDATE accounts SET balance = balance + ? WHERE id = ?";
            String insertTransactionSql = "INSERT INTO transactions (account_id, amount, transaction_type) VALUES (?, ?, ?)";

            updateAccountStmt = connection.prepareStatement(updateAccountSql);
            insertTransactionStmt = connection.prepareStatement(insertTransactionSql);

            // 5. 執(zhí)行轉(zhuǎn)賬操作
            int fromAccountId = 1; // 轉(zhuǎn)出賬戶ID
            int toAccountId = 2;   // 轉(zhuǎn)入賬戶ID
            double amount = 100.00; // 轉(zhuǎn)賬金額

            // 從轉(zhuǎn)出賬戶扣款
            updateAccountStmt.setDouble(1, -amount);
            updateAccountStmt.setInt(2, fromAccountId);
            updateAccountStmt.executeUpdate();

            // 向轉(zhuǎn)入賬戶加款
            updateAccountStmt.setDouble(1, amount);
            updateAccountStmt.setInt(2, toAccountId);
            updateAccountStmt.executeUpdate();

            // 插入交易記錄
            insertTransactionStmt.setInt(1, fromAccountId);
            insertTransactionStmt.setDouble(2, -amount);
            insertTransactionStmt.setString(3, "DEBIT");
            insertTransactionStmt.executeUpdate();

            insertTransactionStmt.setInt(1, toAccountId);
            insertTransactionStmt.setDouble(2, amount);
            insertTransactionStmt.setString(3, "CREDIT");
            insertTransactionStmt.executeUpdate();

            // 6. 提交事務(wù)
            connection.commit();
            System.out.println("Transaction completed successfully.");

        } catch (ClassNotFoundException e) {
            System.err.println("Database driver not found.");
            e.printStackTrace();
        } catch (SQLException e) {
            System.err.println("SQL error occurred. Rolling back transaction.");
            e.printStackTrace();
            try {
                if (connection != null) {
                    connection.rollback(); // 回滾事務(wù)
                }
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        } finally {
            // 7. 關(guān)閉資源
            try {
                if (updateAccountStmt != null) {
                    updateAccountStmt.close();
                }
                if (insertTransactionStmt != null) {
                    insertTransactionStmt.close();
                }
                if (connection != null) {
                    connection.setAutoCommit(true); // 恢復(fù)自動提交
                    connection.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}