java 如何根据taskType 查询不同的表

可以通过使用条件语句和动态 SQL 来实现根据任务类型查询不同的表。

假设有以下两个表：

- task_type_1：包含任务类型为 1 的数据
- task_type_2：包含任务类型为 2 的数据

可以使用以下伪代码实现：

String sql = "SELECT * FROM ";
if (taskType == 1) {
    sql += "task_type_1";
} else if (taskType == 2) {
    sql += "task_type_2";
} else {
    // 处理其他情况
}

在这个例子中，我们通过根据任务类型动态构建 SQL 语句来实现查询不同的表。当任务类型为 1 时，查询的是 task_type_1 表；当任务类型为 2 时，查询的是 task_type_2 表。如果任务类型不是 1 或 2，则可以添加适当的处理逻辑。

请注意，使用动态 SQL 时需要注意防止 SQL 注入攻击。可以使用参数化查询或者输入验证等方式来增加 SQL 查询的安全性。

相关问题

把下表建成java类CREATE TABLE `t_vbs_vas_data_import_task` ( `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键', `created_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间', `updated_time` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '更新时间', `is_deleted` tinyint(1) NOT NULL DEFAULT '0' COMMENT '是否删除', `task_type` smallint(6) NOT NULL DEFAULT '0' COMMENT '任务类型 1-拉数任务 2-补数任务', `task_code` varchar(50) NOT NULL DEFAULT '' COMMENT '任务编码', `task_description` varchar(200) NOT NULL DEFAULT '' COMMENT '任务描述', `last_catch_data_where_start_time` datetime NOT NULL DEFAULT '1900-01-01 00:00:00' COMMENT '上一次取数的条件的执行开始时间', `last_catch_data_where_end_time` datetime NOT NULL DEFAULT '1900-01-01 00:00:00' COMMENT '上一次取数的条件的执行结束时间', `last_catch_data_where_time_step` int(11) NOT NULL DEFAULT '0' COMMENT '上一次取数的条件的执行时间的步频(单位:分钟)', `add_where_condition_of_loan_kind` varchar(200) NOT NULL DEFAULT '' COMMENT '补充where条件之LoanKind', `data_push_batch_num_in_dimension` int(11) NOT NULL DEFAULT '50' COMMENT '维度化的数据推送量(并非真正的batchSize)', PRIMARY KEY (`id`) /*T![clustered_index] CLUSTERED */ ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin AUTO_INCREMENT=270017 COMMENT='从vbs抽取数据至vas的计划任务';

以下是将上述表创建为Java类的示例代码：

import java.util.Date;

public class VbsVasDataImportTask {
    private int id;
    private Date createdTime;
    private Date updatedTime;
    private boolean isDeleted;
    private int taskType;
    private String taskCode;
    private String taskDescription;
    private Date lastCatchDataWhereStartTime;
    private Date lastCatchDataWhereEndTime;
    private int lastCatchDataWhereTimeStep;
    private String addWhereConditionOfLoanKind;
    private int dataPushBatchNumInDimension;

    // 构造函数
    public VbsVasDataImportTask() {
        // 默认构造函数
    }

    // Getters 和 Setters
    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public Date getCreatedTime() {
        return createdTime;
    }

    public void setCreatedTime(Date createdTime) {
        this.createdTime = createdTime;
    }

    public Date getUpdatedTime() {
        return updatedTime;
    }

    public void setUpdatedTime(Date updatedTime) {
        this.updatedTime = updatedTime;
    }

    public boolean getIsDeleted() {
        return isDeleted;
    }

    public void setIsDeleted(boolean isDeleted) {
        this.isDeleted = isDeleted;
    }

    public int getTaskType() {
        return taskType;
    }

    public void setTaskType(int taskType) {
        this.taskType = taskType;
    }

    public String getTaskCode() {
        return taskCode;
    }

    public void setTaskCode(String taskCode) {
        this.taskCode = taskCode;
    }

    public String getTaskDescription() {
        return taskDescription;
    }

    public void setTaskDescription(String taskDescription) {
        this.taskDescription = taskDescription;
    }

    public Date getLastCatchDataWhereStartTime() {
        return lastCatchDataWhereStartTime;
    }

    public void setLastCatchDataWhereStartTime(Date lastCatchDataWhereStartTime) {
        this.lastCatchDataWhereStartTime = lastCatchDataWhereStartTime;
    }

    public Date getLastCatchDataWhereEndTime() {
        return lastCatchDataWhereEndTime;
    }

    public void setLastCatchDataWhereEndTime(Date lastCatchDataWhereEndTime) {
        this.lastCatchDataWhereEndTime = lastCatchDataWhereEndTime;
    }

    public int getLastCatchDataWhereTimeStep() {
        return lastCatchDataWhereTimeStep;
    }

    public void setLastCatchDataWhereTimeStep(int lastCatchDataWhereTimeStep) {
        this.lastCatchDataWhereTimeStep = lastCatchDataWhereTimeStep;
    }

    public String getAddWhereConditionOfLoanKind() {
        return addWhereConditionOfLoanKind;
    }

    public void setAddWhereConditionOfLoanKind(String addWhereConditionOfLoanKind) {
        this.addWhereConditionOfLoanKind = addWhereConditionOfLoanKind;
    }

    public int getDataPushBatchNumInDimension() {
        return dataPushBatchNumInDimension;
    }

    public void setDataPushBatchNumInDimension(int dataPushBatchNumInDimension) {
        this.dataPushBatchNumInDimension = dataPushBatchNumInDimension;
    }
}

在上述代码中，我们将表中的字段映射到了Java类中的属性，并提供了相应的Getters和Setters方法。这样，我们就可以在Java中方便地操作该表的数据了。

kotlin 代码使用AIDL 技术实现一个服务端可以接收来自多个不同的APP客户端的请求，要区分来自哪一个客户端app的什么类型请求，把请求加入任务栈，任务栈用一个单独的类TaskStack来管理，任务和注册的回调消息绑定。在一个子线程中while循环取出任务栈中的任务，有一个Dispach类来管理任务的分发，在Dispach类中按照请求的优先级同步或者异步的将任务分发执行,还需要考虑任务的优先级、同步或异步处理等问题，执行完成后通过Dispach把消息回调给发请求的那个客户端app，要求线程安全，给出详细的每一个类的代码

好的，以下是Kotlin代码实现：

Task.kt

data class Task(val clientId: String, val taskType: String, val priority: Int, val task: Runnable)

TaskStack.kt

import java.util.*
import java.util.concurrent.locks.ReentrantLock

class TaskStack {
    private val lock = ReentrantLock()
    private val taskQueue: Queue<Task> = PriorityQueue(Comparator<Task> { t1, t2 -> t1.priority - t2.priority })

    fun addTask(task: Task) {
        lock.lock()
        taskQueue.add(task)
        lock.unlock()
    }

    fun getTask(): Task? {
        lock.lock()
        val task = taskQueue.poll()
        lock.unlock()
        return task
    }
}

Dispatcher.kt

import java.util.concurrent.ExecutorService
import java.util.concurrent.Executors

class Dispatcher {
    private val executorService: ExecutorService = Executors.newCachedThreadPool()

    fun dispatchTask(task: Task, callback: Callback) {
        val runnable = Runnable {
            val result = task.task.run()
            callback.onResult(task.clientId, task.taskType, result)
        }
        if (task.priority == TaskPriority.HIGH) {
            executorService.execute(runnable)
        } else {
            runnable.run()
        }
    }

    interface Callback {
        fun onResult(clientId: String, taskType: String, result: Any)
    }
}

TaskPriority.kt

object TaskPriority {
    const val LOW = 0
    const val HIGH = 1
}

TaskHandler.kt

import android.os.Handler
import android.os.IBinder
import android.os.RemoteException

class TaskHandler(private val taskStack: TaskStack) : ITaskHandler.Stub() {
    private val dispatch = Dispatcher()

    override fun addTask(clientId: String, taskType: String, priority: Int, task: ITask): Boolean {
        val runnable = Runnable {
            try {
                task.run()
            } catch (e: RemoteException) {
                e.printStackTrace()
            }
        }
        taskStack.addTask(Task(clientId, taskType, priority, runnable))
        return true
    }

    override fun registerCallback(clientId: String, taskType: String, callback: ITaskCallback) {
        // TODO: 将callback注册到任务和任务结果的映射表中
    }

    override fun unregisterCallback(clientId: String, taskType: String) {
        // TODO: 从任务和任务结果的映射表中移除callback
    }

    fun start() {
        Thread {
            while (true) {
                val task = taskStack.getTask()
                if (task == null) {
                    Thread.sleep(1000)
                    continue
                }
                val callback = getCallback(task.clientId, task.taskType)
                dispatch.dispatchTask(task, object : Dispatcher.Callback {
                    override fun onResult(clientId: String, taskType: String, result: Any) {
                        try {
                            callback?.onResult(result)
                        } catch (e: RemoteException) {
                            e.printStackTrace()
                        }
                    }
                })
            }
        }.start()
    }

    private fun getCallback(clientId: String, taskType: String): ITaskCallback? {
        // TODO: 从任务和任务结果的映射表中获取callback
        return null
    }
}

ITaskHandler.aidl

interface ITaskHandler {
    boolean addTask(in String clientId, in String taskType, in int priority, in ITask task);
    void registerCallback(in String clientId, in String taskType, in ITaskCallback callback);
    void unregisterCallback(in String clientId, in String taskType);
}

ITask.aidl

interface ITask {
    void run();
}

ITaskCallback.aidl

interface ITaskCallback {
    void onResult(in Object result);
}