MySQL实现乐观锁的方式详解

// 读取数据
String sql = "SELECT id, name, version FROM table_name WHERE id = ?";
PreparedStatement pstmt = connection.prepareStatement(sql);
pstmt.setInt(1, id);
ResultSet rs = pstmt.executeQuery();
if (rs.next()) {
    int version = rs.getInt("version");
    // 更新数据
    String updateSql = "UPDATE table_name SET name = ?, version = ? WHERE id = ? AND version = ?";
    PreparedStatement updateStmt = connection.prepareStatement(updateSql);
    updateStmt.setString(1, newName);
    updateStmt.setInt(2, version + 1);
    updateStmt.setInt(3, id);
    updateStmt.setInt(4, version);
    int affectedRows = updateStmt.executeUpdate();
    if (affectedRows == 0) {
        // 更新失败，数据已被其他事务修改
        // 进行相应的处理
    }
}

// 读取数据
String sql = "SELECT id, name, timestamp FROM table_name WHERE id = ?";
PreparedStatement pstmt = connection.prepareStatement(sql);
pstmt.setInt(1, id);
ResultSet rs = pstmt.executeQuery();
if (rs.next()) {
    Timestamp timestamp = rs.getTimestamp("timestamp");
    // 更新数据
    String updateSql = "UPDATE table_name SET name = ?, timestamp = ? WHERE id = ? AND timestamp = ?";
    PreparedStatement updateStmt = connection.prepareStatement(updateSql);
    updateStmt.setString(1, newName);
    updateStmt.setTimestamp(2, newTimestamp);
    updateStmt.setInt(3, id);
    updateStmt.setTimestamp(4, timestamp);
    int affectedRows = updateStmt.executeUpdate();
    if (affectedRows == 0) {
        // 更新失败，数据已被其他事务修改
        // 进行相应的处理
    }
}