温岭建设网站,广州网站建设哪个平台好,设计专业,WordPress音乐悬浮插件1、broadcast广播 在Spark中#xff0c;broadcast是一种优化技术#xff0c;它可以将一个只读变量缓存到每个节点上#xff0c;以便在执行任务时使用。这样可以避免在每个任务中重复传输数据。
2、构建缓存
import org.apache.spark.sql.SparkSession
import org.apache.s…1、broadcast广播 在Spark中broadcast是一种优化技术它可以将一个只读变量缓存到每个节点上以便在执行任务时使用。这样可以避免在每个任务中重复传输数据。
2、构建缓存
import org.apache.spark.sql.SparkSession
import org.apache.spark.broadcast.Broadcast
import com.alibaba.fastjson.JSONObject// 定义全局缓存单例对象
object GlobalCache extends Serializable {// 广播变量用于存储缓存数据private var cacheData: Broadcast[collection.mutable.Map[String, JSONObject]] _// 设置 SparkSession 和广播变量def setSparkSession(spark: SparkSession): Unit {cacheData spark.sparkContext.broadcast(collection.mutable.Map.empty[String, JSONObject])}// 按订单ID和用户ID缓存JSONObject对象def cacheJSONObject(orderId: String, userId: String, jsonObject: JSONObject): Unit {// 获取广播变量的值并进行修改val data cacheData.valuedata.synchronized {data.put(generateKey(orderId, userId), jsonObject)}}// 根据订单ID和用户ID删除缓存的JSONObject对象def removeJSONObject(orderId: String, userId: String): Unit {// 获取广播变量的值并进行修改val data cacheData.valuedata.synchronized {data.remove(generateKey(orderId, userId))}}// 根据订单ID和用户ID获取缓存的JSONObject对象def getJSONObjet(orderId: String, userId: String): JSONObject {// 获取广播变量的值并进行访问val data cacheData.valuedata.synchronized {data.get(generateKey(orderId, userId)).orNull}}// 生成缓存键使用订单ID和用户ID拼接private def generateKey(orderId: String, userId: String): String s$orderId|$userId
}3、缓存测试
import org.apache.spark.sql.SparkSession
import org.apache.spark.broadcast.Broadcast
import com.alibaba.fastjson.JSONObject
import org.apache.log4j.{Level, Logger}object CacheTest {Logger.getLogger(org).setLevel(Level.ERROR)Logger.getRootLogger().setLevel(Level.ERROR) // 设置日志级别def addItem(orderId:String, userId:String, name:String): Unit {val jsonObject new JSONObject()jsonObject.put(name, name)// 缓存JSONObject对象GlobalCache.cacheJSONObject(orderId, userId, jsonObject)}def getCache(orderId: String, userId: String): JSONObject {// 获取缓存的JSONObject对象GlobalCache.getJSONObjet(orderId, userId)}def delItem(orderId:String, userId:String): Unit {// 删除缓存的JSONObject对象GlobalCache.removeJSONObject(orderId, userId)}def getSparkSession(appName: String, localType: Int): SparkSession {val builder: SparkSession.Builder SparkSession.builder().appName(appName)if (localType 1) {builder.master(local[8]) // 本地模式启用8个核心}val spark builder.getOrCreate() // 获取或创建一个新的SparkSessionspark.sparkContext.setLogLevel(ERROR) // Spark设置日志级别spark}def main(args: Array[String]): Unit {println(Start CacheTest)val spark: SparkSession getSparkSession(CacheTest, 1)GlobalCache.setSparkSession(spark) // 构造全局缓存addItem(001, 456, 苹果) // 添加元素addItem(002, 789, 香蕉) // 添加元素var cachedObject getCache(001, 456)println(sCached Object: $cachedObject)delItem(001, 456) // 删除元素cachedObject getCache(001, 456)println(sCached Object: $cachedObject)spark.stop()}
}4、控制台输出
Start CacheTest
Using Sparks default log4j profile: org/apache/spark/log4j-defaults.properties
Cached Object: {name:苹果}
Cached Object: nullProcess finished with exit code 0
