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將python檔案提交到本地服務器時,Windows10上的Sparktwitter流應用程式出錯

2021-12-10 03:05:53 前端設計

我正在嘗試運行一個流應用程式,為特定用戶計算推文。生產者代碼:

# -*- coding: utf-8 -*-
import tweepy
import json
import base64
from kafka import KafkaProducer
import kafka.errors

# Twitter API credentials
CONSUMER_KEY   = "***"
CONSUMER_SECRET   = "***"
ACCESS_TOKEN   = "***"
ACCESS_TOKEN_SECRET   = "***"

# Kafka topic name
TOPIC_NAME = "tweet-kafka"

# Kafka server
KAFKA_HOST = "localhost"
KAFKA_PORT = "9092"

#a list of ids, the actual ids have been hidden in this question
ids = ["11111", "222222"]

auth= tweepy.OAuthHandler(CONSUMER_KEY,CONSUMER_SECRET)
auth.set_access_token(ACCESS_TOKEN,ACCESS_TOKEN_SECRET)

class KafkaCommunicator:
    def __init__(self, producer, topic):
        self.producer = producer
        self.topic = topic

    def send(self, message):
        self.producer.send(self.topic, message.encode("utf-8"))

    def close(self):
        self.producer.close()
        
class MyStreamListener(tweepy.StreamListener):
    """Listener to tweet stream from twitter."""
    def __init__(self,communicator,api=None):
        super(MyStreamListener,self).__init__()
        self.communicator = communicator
        self.num_tweets=0

    def on_data(self, raw_data):
        data = json.loads(raw_data)
        #print(data)
        if "user" in data:
            user_id = data["user"]["id_str"]
            if user_id in ids:
                print("Time: "   data["created_at"]   "; id: "   user_id   "; screen_name: "   data["user"]["screen_name"] )
                # put message into Kafka
                self.communicator.send(data["user"]["screen_name"])
        return True
        
    def on_error(self, status):
        print(status)
        return True

def create_communicator():
    """Create Kafka producer."""
    producer = KafkaProducer(bootstrap_servers=KAFKA_HOST   ":"   KAFKA_PORT)
    return KafkaCommunicator(producer, TOPIC_NAME)


def create_stream(communicator):
    """Set stream for twitter api with custom listener."""
    listener = MyStreamListener(communicator=communicator)
    stream =tweepy.Stream(auth,listener)
    return stream

def run_processing(stream):
    # Start filtering messages
    stream.filter(follow=ids)

def main():
    communicator = None
    tweet_stream = None
    try:
        communicator = create_communicator()
        tweet_stream = create_stream(communicator)
        run_processing(tweet_stream)
    except KeyboardInterrupt:
        pass
    except kafka.errors.NoBrokersAvailable:
        print("Kafka broker not found.")
    finally:
        if communicator:
            communicator.close()
        if tweet_stream:
            tweet_stream.disconnect()


if __name__ == "__main__":
    main()

流媒體應用代碼:

# -*- coding: utf-8 -*-
import sys
import os

spark_path = "D:/spark/spark-2.4.7-bin-hadoop2.7" # spark installed folder
os.environ['SPARK_HOME'] = spark_path
os.environ['HADOOP_HOME'] = spark_path
sys.path.insert(0, spark_path   "/bin")
sys.path.insert(0, spark_path   "/python/pyspark/")
sys.path.insert(0, spark_path   "/python/lib/pyspark.zip")
sys.path.insert(0, spark_path   "/python/lib/py4j-0.10.7-src.zip")

os.environ['PYSPARK_SUBMIT_ARGS'] = '--packages org.apache.spark:spark-streaming-kafka-0-8_2.11:2.4.7 pyspark-shell'
os.environ['PYSPARK_DRIVER_PYTHON_OPTS']= "notebook"
os.environ['PYSPARK_DRIVER_PYTHON'] = sys.executable
os.environ['PYSPARK_PYTHON'] = sys.executable
os.environ['PYTHONHASHSEED'] = "0"
os.environ['SPARK_YARN_USER_ENV'] = PYTHONHASHSEED = "0"

from pyspark import SparkContext, SparkConf
from pyspark.streaming import StreamingContext
from pyspark.streaming.kafka import KafkaUtils

SPARK_APP_NAME = "SparkStreamingKafkaTwitter"
SPARK_CHECKPOINT_TMP_DIR = "D:/tmp"
SPARK_BATCH_INTERVAL = 10
SPARK_LOG_LEVEL = "OFF"

KAFKA_BOOTSTRAP_SERVERS = "localhost:9092" #Default Zookeeper Consumer Address
KAFKA_TOPIC = "tweet-kafka"

import json

def create_streaming_context():
    """Create Spark streaming context."""
    conf = SparkConf().set("spark.executor.memory", "2g")\
                .set("spark.driver.memory", "2g")\
                .set("spark.driver.bindAddress", "0.0.0.0")
    # Create Spark Context
    sc = SparkContext(master = "local[2]", appName=SPARK_APP_NAME, conf = conf)
    # Set log level
    sc.setLogLevel(SPARK_LOG_LEVEL)
    # Create Streaming Context
    ssc = StreamingContext(sc, SPARK_BATCH_INTERVAL)
    # Sets the context to periodically checkpoint the DStream operations for master
    # fault-tolerance. The graph will be checkpointed every batch interval.
    # It is used to update results of stateful transformations as well
    ssc.checkpoint(SPARK_CHECKPOINT_TMP_DIR)
    return ssc

def create_stream(ssc):
    """
    Create subscriber (consumer) to the Kafka topic (works on RDD that is mini-batch).
    """
    return (
        KafkaUtils.createDirectStream(
            ssc, topics=[KAFKA_TOPIC],
            kafkaParams={"bootstrap.servers": KAFKA_BOOTSTRAP_SERVERS})
            .map(lambda x:x[1])
    )

def main():

    # Init Spark streaming context
    ssc = create_streaming_context()

    # Get tweets stream
    kafka_stream = create_stream(ssc)

    # using reduce, count the number of user's tweets for x minute every 30 seconds
    # descending sort the result
    # Print result
    
    # for 1 minute
    tweets_for_1_min = kafka_stream.reduceByKeyAndWindow(lambda x,y: x   y, lambda x,y: x - y, windowDuration=60, slideDuration=30)
    sorted_tweets_for_1_min = tweets_for_1_min.transform(lambda x_rdd: x_rdd.sortBy(lambda x: x[1], ascending=False))
    sorted_tweets_for_1_min.pprint()
    
    # for 10 minute
    tweets_for_10_min = kafka_stream.reduceByKeyAndWindow(lambda x,y: x   y, lambda x,y: x - y, windowDuration=600, slideDuration=30)
    sorted_tweets_for_10_min = tweets_for_10_min.transform(lambda x_rdd: x_rdd.sortBy(lambda x: [1], ascending=False))
    sorted_tweets_for_10_min.pprint()

    # Start Spark Streaming
    ssc.start()

    # Waiting for termination
    ssc.awaitTermination()


if __name__ == "__main__":
    main()

我已經安裝了以下內容:

  1. jdk1.8.0_311 和 jre1.8.0_311
  2. 蟒蛇 2.7
  3. hadoop-2.7.1 運行正常
  4. spark-2.4.7-bin-hadoop2.7
  5. kafka_2.13-3.0.0 我已經正確設定了環境變數但是在執行提交命令后我在運行時收到以下例外:
spark-submit --master local[2] --packages org.apache.spark:spark-streaming-kafka-0-8_2.11:2.4.7 d:\task1\tweet_kafka_streaming_app.py

處理流時發生例外:

-------------------------------------------
Time: 2021-12-06 15:28:30
-------------------------------------------

-------------------------------------------
Time: 2021-12-06 15:28:30
-------------------------------------------

Traceback (most recent call last):
  File "d:/task1/tweet_kafka_streaming_app.py", line 95, in <module>
    main()
  File "d:/task1/tweet_kafka_streaming_app.py", line 91, in main
    ssc.awaitTermination()
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\streaming\context.py", line 192, in awaitTermination
    varName = k[len("spark.executorEnv."):]
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\py4j-0.10.7-src.zip\py4j\java_gateway.py", line 1257, in __call__

  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\py4j-0.10.7-src.zip\py4j\protocol.py", line 328, in get_return_value
py4j.protocol.Py4JJavaError: An error occurred while calling o32.awaitTermination.
: org.apache.spark.SparkException: An exception was raised by Python:
Traceback (most recent call last):
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\streaming\util.py", line 68, in call
    r = self.func(t, *rdds)
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\streaming\dstream.py", line 297, in <lambda>
    func = lambda t, rdd: oldfunc(rdd)
  File "d:/task1/tweet_kafka_streaming_app.py", line 79, in <lambda>
    sorted_tweets_for_1_min = tweets_for_1_min.transform(lambda x_rdd: x_rdd.sortBy(lambda x: x[1], ascending=False))
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\rdd.py", line 699, in sortBy
    return self.keyBy(keyfunc).sortByKey(ascending, numPartitions).values()
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\rdd.py", line 667, in sortByKey
    rddSize = self.count()
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\rdd.py", line 1055, in count
    return self.mapPartitions(lambda i: [sum(1 for _ in i)]).sum()
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\rdd.py", line 1046, in sum
    return self.mapPartitions(lambda x: [sum(x)]).fold(0, operator.add)
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\rdd.py", line 917, in fold
    vals = self.mapPartitions(func).collect()
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\rdd.py", line 816, in collect
    sock_info = self.ctx._jvm.PythonRDD.collectAndServe(self._jrdd.rdd())
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\py4j-0.10.7-src.zip\py4j\java_gateway.py", line 1257, in __call__
    answer, self.gateway_client, self.target_id, self.name)
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\py4j-0.10.7-src.zip\py4j\protocol.py", line 328, in get_return_value
    format(target_id, ".", name), value)
Py4JJavaError: An error occurred while calling z:org.apache.spark.api.python.PythonRDD.collectAndServe.
: org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 23.0 failed 1 times, most recent failure: Lost task 0.0 in stage 23.0 (TID 20, localhost, executor driver): org.apache.spark.api.python.PythonException: Traceback (most recent call last):
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\worker.py", line 377, in main
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\worker.py", line 372, in process
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\rdd.py", line 2499, in pipeline_func
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\rdd.py", line 352, in func
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\rdd.py", line 1861, in combineLocally
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\shuffle.py", line 238, in mergeValues
    for k, v in iterator:
ValueError: too many values to unpack

        at org.apache.spark.api.python.BasePythonRunner$ReaderIterator.handlePythonException(PythonRunner.scala:456)
        at org.apache.spark.api.python.PythonRunner$$anon$1.read(PythonRunner.scala:592)
        at org.apache.spark.api.python.PythonRunner$$anon$1.read(PythonRunner.scala:575)
        at org.apache.spark.api.python.BasePythonRunner$ReaderIterator.hasNext(PythonRunner.scala:410)
        at org.apache.spark.InterruptibleIterator.hasNext(InterruptibleIterator.scala:37)
        at scala.collection.Iterator$GroupedIterator.fill(Iterator.scala:1124)
        at scala.collection.Iterator$GroupedIterator.hasNext(Iterator.scala:1130)
        at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:409)
        at org.apache.spark.shuffle.sort.BypassMergeSortShuffleWriter.write(BypassMergeSortShuffleWriter.java:125)
        at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:99)
        at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:55)
        at org.apache.spark.scheduler.Task.run(Task.scala:123)
        at org.apache.spark.executor.Executor$TaskRunner$$anonfun$10.apply(Executor.scala:408)
        at org.apache.spark.util.Utils$.tryWithSafeFinally(Utils.scala:1360)
        at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:414)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)

Driver stacktrace:
        at org.apache.spark.scheduler.DAGScheduler.org$apache$spark$scheduler$DAGScheduler$$failJobAndIndependentStages(DAGScheduler.scala:1925)
        at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1913)
        at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1912)
        at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
        at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:48)
        at org.apache.spark.scheduler.DAGScheduler.abortStage(DAGScheduler.scala:1912)
        at org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:948)
        at org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:948)
        at scala.Option.foreach(Option.scala:257)
        at org.apache.spark.scheduler.DAGScheduler.handleTaskSetFailed(DAGScheduler.scala:948)
        at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.doOnReceive(DAGScheduler.scala:2146)
        at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:2095)
        at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:2084)
        at org.apache.spark.util.EventLoop$$anon$1.run(EventLoop.scala:49)
        at org.apache.spark.scheduler.DAGScheduler.runJob(DAGScheduler.scala:759)
        at org.apache.spark.SparkContext.runJob(SparkContext.scala:2061)
        at org.apache.spark.SparkContext.runJob(SparkContext.scala:2082)
        at org.apache.spark.SparkContext.runJob(SparkContext.scala:2101)
        at org.apache.spark.SparkContext.runJob(SparkContext.scala:2126)
        at org.apache.spark.rdd.RDD$$anonfun$collect$1.apply(RDD.scala:990)
        at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:151)
        at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:112)
        at org.apache.spark.rdd.RDD.withScope(RDD.scala:385)
        at org.apache.spark.rdd.RDD.collect(RDD.scala:989)
        at org.apache.spark.api.python.PythonRDD$.collectAndServe(PythonRDD.scala:166)
        at org.apache.spark.api.python.PythonRDD.collectAndServe(PythonRDD.scala)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
        at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
        at py4j.Gateway.invoke(Gateway.java:282)
        at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
        at py4j.commands.CallCommand.execute(CallCommand.java:79)
        at py4j.GatewayConnection.run(GatewayConnection.java:238)
        at java.lang.Thread.run(Unknown Source)
Caused by: org.apache.spark.api.python.PythonException: Traceback (most recent call last):
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\worker.py", line 377, in main
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\worker.py", line 372, in process
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\rdd.py", line 2499, in pipeline_func
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\rdd.py", line 352, in func
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\rdd.py", line 1861, in combineLocally
  File "D:\spark\spark-2.4.7-bin-hadoop2.7\python\lib\pyspark.zip\pyspark\shuffle.py", line 238, in mergeValues
    for k, v in iterator:
ValueError: too many values to unpack

        at org.apache.spark.api.python.BasePythonRunner$ReaderIterator.handlePythonException(PythonRunner.scala:456)
        at org.apache.spark.api.python.PythonRunner$$anon$1.read(PythonRunner.scala:592)
        at org.apache.spark.api.python.PythonRunner$$anon$1.read(PythonRunner.scala:575)
        at org.apache.spark.api.python.BasePythonRunner$ReaderIterator.hasNext(PythonRunner.scala:410)
        at org.apache.spark.InterruptibleIterator.hasNext(InterruptibleIterator.scala:37)
        at scala.collection.Iterator$GroupedIterator.fill(Iterator.scala:1124)
        at scala.collection.Iterator$GroupedIterator.hasNext(Iterator.scala:1130)
        at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:409)
        at org.apache.spark.shuffle.sort.BypassMergeSortShuffleWriter.write(BypassMergeSortShuffleWriter.java:125)
        at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:99)
        at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:55)
        at org.apache.spark.scheduler.Task.run(Task.scala:123)
        at org.apache.spark.executor.Executor$TaskRunner$$anonfun$10.apply(Executor.scala:408)
        at org.apache.spark.util.Utils$.tryWithSafeFinally(Utils.scala:1360)
        at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:414)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        ... 1 more


        at org.apache.spark.streaming.api.python.TransformFunction.callPythonTransformFunction(PythonDStream.scala:95)
        at org.apache.spark.streaming.api.python.TransformFunction.apply(PythonDStream.scala:78)
        at org.apache.spark.streaming.api.python.PythonTransformedDStream.compute(PythonDStream.scala:246)
        at org.apache.spark.streaming.dstream.DStream$$anonfun$getOrCompute$1$$anonfun$1$$anonfun$apply$7.apply(DStream.scala:342)
        at org.apache.spark.streaming.dstream.DStream$$anonfun$getOrCompute$1$$anonfun$1$$anonfun$apply$7.apply(DStream.scala:342)
        at scala.util.DynamicVariable.withValue(DynamicVariable.scala:58)
        at org.apache.spark.streaming.dstream.DStream$$anonfun$getOrCompute$1$$anonfun$1.apply(DStream.scala:341)
        at org.apache.spark.streaming.dstream.DStream$$anonfun$getOrCompute$1$$anonfun$1.apply(DStream.scala:341)
        at org.apache.spark.streaming.dstream.DStream.createRDDWithLocalProperties(DStream.scala:416)
        at org.apache.spark.streaming.dstream.DStream$$anonfun$getOrCompute$1.apply(DStream.scala:336)
        at org.apache.spark.streaming.dstream.DStream$$anonfun$getOrCompute$1.apply(DStream.scala:334)
        at scala.Option.orElse(Option.scala:289)
        at org.apache.spark.streaming.dstream.DStream.getOrCompute(DStream.scala:331)
        at org.apache.spark.streaming.dstream.ForEachDStream.generateJob(ForEachDStream.scala:48)
        at org.apache.spark.streaming.DStreamGraph$$anonfun$1.apply(DStreamGraph.scala:122)
        at org.apache.spark.streaming.DStreamGraph$$anonfun$1.apply(DStreamGraph.scala:121)
        at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:241)
        at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:241)
        at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
        at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:48)
        at scala.collection.TraversableLike$class.flatMap(TraversableLike.scala:241)
        at scala.collection.AbstractTraversable.flatMap(Traversable.scala:104)
        at org.apache.spark.streaming.DStreamGraph.generateJobs(DStreamGraph.scala:121)
        at org.apache.spark.streaming.scheduler.JobGenerator$$anonfun$3.apply(JobGenerator.scala:249)
        at org.apache.spark.streaming.scheduler.JobGenerator$$anonfun$3.apply(JobGenerator.scala:247)
        at scala.util.Try$.apply(Try.scala:192)
        at org.apache.spark.streaming.scheduler.JobGenerator.generateJobs(JobGenerator.scala:247)
        at org.apache.spark.streaming.scheduler.JobGenerator.org$apache$spark$streaming$scheduler$JobGenerator$$processEvent(JobGenerator.scala:183)
        at org.apache.spark.streaming.scheduler.JobGenerator$$anon$1.onReceive(JobGenerator.scala:89)
        at org.apache.spark.streaming.scheduler.JobGenerator$$anon$1.onReceive(JobGenerator.scala:88)
        at org.apache.spark.util.EventLoop$$anon$1.run(EventLoop.scala:49)

Exception in thread Thread-4 (most likely raised during interpreter shutdown):

C:\WINDOWS\system32>

uj5u.com熱心網友回復:

由于@OneCricketeer 給出的提示,我已經解決了這個問題。我將 python 升級到 3.8,但遇到了另一個錯誤。降級到python 3.7,支持Spark 2.4.8或Spark 2.4.7 with Hadoop 2.7,我的世界又亮了。

轉載請註明出處,本文鏈接:https://www.uj5u.com/qianduan/377929.html

標籤:python-2.7 阿帕奇火花 阿帕奇卡夫卡 火花流

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    uj5u.com 2020-09-10 04:38:07 more
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    一個個人用的瀏覽器首頁,可以把一下常用的網站放在這里,平常打開會比較方便。 第一步,HTML代碼 <script src=https://www.cnblogs.com/szharf/p/"js/jquery-3.4.1.min.js"></script> <div id="navigate"> <ul> <li class="labels labels_1"> ......

    uj5u.com 2020-09-10 04:38:47 more
  • 頁面為要加<!DOCTYPE html>

    最近因為寫一個js函式,需要用到$(window).height(); 由于手寫demo的時候,過于自信,其實對前端方面的認識也不夠體系,用文本檔案直接敲出來的html代碼,第一行沒有加上<!DOCTYPE html> 導致了$(window).height();的結果直接是整個document的高 ......

    uj5u.com 2020-09-10 04:38:52 more
  • WordPress網站程式手動升級要做好資料備份

    WordPress博客網站程式在進行升級前,必須要做好網站資料的備份,這個問題良家佐言是遇見過的;在剛開始接觸WordPress博客程式的時候,因為升級問題和博客網站的修改的一些嘗試,良家佐言是吃盡了苦頭。因為購買的是西部數碼的空間和域名,每當佐言把自己的WordPress博客網站搞到一塌糊涂的時候 ......

    uj5u.com 2020-09-10 04:39:30 more
  • WordPress程式不能升級為5.4.2版本的原因

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    uj5u.com 2020-09-10 04:39:49 more
  • 使用CSS3的偽元素進行首字母下沉和首行改變樣式

    網頁中常見的一種效果,首字改變樣式或者首行改變樣式,效果如下圖。 代碼: <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, ......

    uj5u.com 2020-09-10 04:40:09 more
  • 關于a標簽的講解

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    uj5u.com 2020-09-10 04:40:11 more
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    在需要輪播的頁面是引入swiper.min.js和swiper.min.css swiper.min.js地址: 鏈接:https://pan.baidu.com/s/15Uh516YHa4CV3X-RyjEIWw 提取碼:4aks swiper.min.css地址 鏈接:https://pan.b ......

    uj5u.com 2020-09-10 04:40:13 more
  • 如何設定html中的背景圖片(全屏顯示,且不拉伸)

    1 <style>2 body{background-image:url(https://uploadbeta.com/api/pictures/random/?key=BingEverydayWallpaperPicture); 3 background-size:cover;background ......

    uj5u.com 2020-09-10 04:40:16 more
  • Java學習——HTML詳解(上)

    HTML詳解 初識HTML Hyper Text Markup Language(超文本標記語言) 1 <!--DOCTYPE:告訴瀏覽器我們要使用什么規范--> 2 <!DOCTYPE html> 3 <html lang="en"> 4 <head> 5 <!--meta 描述性的標簽,描述一些 ......

    uj5u.com 2020-09-10 04:40:33 more
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    uj5u.com 2023-04-20 07:59:23 more
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    uj5u.com 2023-04-18 07:55:04 more
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    uj5u.com 2023-04-04 08:35:30 more
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    uj5u.com 2023-03-16 11:00:15 more
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    //11.開啟藍牙配接器 openBluetoothAdapter //21.開始搜索藍牙設備 startBluetoothDevicesDiscovery //31.開啟監聽搜索藍牙設備 onBluetoothDeviceFound //30.停止監聽搜索藍牙設備 offBluetoothDevi ......

    uj5u.com 2023-03-15 09:06:45 more
  • canvas畫板(滑鼠和觸摸)

    <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>canves</title> <style> #canvas { cursor:url(../images/pen.png),crosshair; } #canvasdiv{ bo ......

    uj5u.com 2023-02-15 08:56:31 more
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    uj5u.com 2023-01-12 07:58:22 more
  • 記錄--短視頻滑動播放在 H5 下的實作

    這里給大家分享我在網上總結出來的一些知識,希望對大家有所幫助 短視頻已經無數不在了,但是主體還是使用 app 來承載的。本文講述 H5 如何實作 app 的視頻滑動體驗。 無聲勝有聲,一圖頂百辯,且看下圖: 網址鏈接(需在微信或者手Q中瀏覽) 從上圖可以看到,我們主要實作的功能也是本文要講解的有: ......

    uj5u.com 2023-01-04 07:29:05 more
  • 一文讀懂 HTTP/1 HTTP/2 HTTP/3

    從 1989 年萬維網(www)誕生,HTTP(HyperText Transfer Protocol)經歷了眾多版本迭代,WebSocket 也在期間萌芽。1991 年 HTTP0.9 被發明。1996 年出現了 HTTP1.0。2015 年 HTTP2 正式發布。2020 年 HTTP3 或能正... ......

    uj5u.com 2022-12-24 06:56:02 more
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    ??一、form表單是什么

    ??二、form表單的屬性

    ??三、input中的各種Type屬性值

    ??四、標簽 ......

    uj5u.com 2022-12-18 07:17:06 more