轉載自:http://blog.csdn.net/jiutianhe/article/details/39233609
我們如果想搞開發,研究源碼對我們的幫助很大。不明白原理就如同黑盒子,遇到問題,我們也摸不著思路。所以這里交給大家一.如何獲取源碼二.如何關聯源碼一.如何獲取源碼1.下載hadoop的maven程序包(1)官網下載這里我們先從官網上下載maven包hadoop-2.4.0-src.tar.gz。官網下載地址對于不知道怎么去官網下載,可以查看:新手指導:hadoop官網介紹及如何下載hadoop(2.4)各個版本與查看hadoop API介紹(2)網盤下載也可以從網盤下載:http://pan.baidu.com/s/1kToPuGB2.通過maven獲取源碼獲取源碼的方式有兩種,一種是通過命令行的方式,一種是通過eclipse。這里主要講通過命令的方式通過命令的方式獲取源碼:1.解壓包1 : 無法創建文件:D:/hadoop2/hadoop-2.4.0-src/hadoop-yarn-PRoject/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/target/classes/org/apache/hadoop/yarn/server/applicationhistoryservice/ApplicationHistoryClientService$ApplicationHSClientProtocolHandler.class:路徑和文件名總長度不能超過260個字符系統找不到指定的路徑。 D:/hadoop2/hadoop-2.4.0-src.zip2 : 無法創建文件:D:/hadoop2/hadoop-2.4.0-src/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/target/classes/org/apache/hadoop/yarn/server/applicationhistoryservice/timeline/LeveldbTimelineStore$LockMap$CountingReentrantLock.class:系統找不到指定的路徑。 D:/hadoop2/hadoop-2.4.0-src.zip3 : 無法創建文件:D:/hadoop2/hadoop-2.4.0-src/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/target/test-classes/org/apache/hadoop/yarn/server/applicationhistoryservice/webapp/TestAHSWebApp$MockApplicationHistoryManagerImpl.class:系統找不到指定的路徑。 D:/hadoop2/hadoop-2.4.0-src.zip4 : 無法創建文件:D:/hadoop2/hadoop-2.4.0-src/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/target/test-classes/org/apache/hadoop/yarn/server/resourcemanager/monitor/capacity/TestProportionalCapacityPreemptionPolicy$IsPreemptionRequestFor.class:路徑和文件名總長度不能超過260個字符系統找不到指定的路徑。 D:/hadoop2/hadoop-2.4.0-src.zip5 : 無法創建文件:D:/hadoop2/hadoop-2.4.0-src/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/target/test-classes/org/apache/hadoop/yarn/server/resourcemanager/recovery/TestFSRMStateStore$TestFSRMStateStoreTester$TestFileSystemRMStore.class:系統找不到指定的路徑。 D:/hadoop2/hadoop-2.4.0-src.zip6 : 無法創建文件:D:/hadoop2/hadoop-2.4.0-src/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/target/test-classes/org/apache/hadoop/yarn/server/resourcemanager/recovery/TestZKRMStateStore$TestZKRMStateStoreTester$TestZKRMStateStoreInternal.class:路徑和文件名總長度不能超過260個字符系統找不到指定的路徑。 D:/hadoop2/hadoop-2.4.0-src.zip7 : 無法創建文件:D:/hadoop2/hadoop-2.4.0-src/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/target/test-classes/org/apache/hadoop/yarn/server/resourcemanager/recovery/TestZKRMStateStoreZKClientConnections$TestZKClient$TestForwardingWatcher.class:路徑和文件名總長度不能超過260個字符系統找不到指定的路徑。 D:/hadoop2/hadoop-2.4.0-src.zip8 : 無法創建文件:D:/hadoop2/hadoop-2.4.0-src/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/target/test-classes/org/apache/hadoop/yarn/server/resourcemanager/recovery/TestZKRMStateStoreZKClientConnections$TestZKClient$TestZKRMStateStore.class:路徑和文件名總長度不能超過260個字符系統找不到指定的路徑。 D:/hadoop2/hadoop-2.4.0-src.zip9 : 無法創建文件:D:/hadoop2/hadoop-2.4.0-src/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/target/test-classes/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/TestRMAppAttemptTransitions$TestApplicationAttemptEventDispatcher.class:路徑和文件名總長度不能超過260個字符系統找不到指定的路徑。 D:/hadoop2/hadoop-2.4.0-src.zip2.通過maven獲取源碼這里需要說明的是,在使用maven的時候,需要先安裝jdk,protoc ,如果沒有安裝可以參考Win7如何安裝maven、安裝protoc(1)進入hadoop-2.4.0-src/hadoop-maven-plugins,運行mvn installD:/hadoop2/hadoop-2.4.0-src/hadoop-maven-plugins>mvn install復制代碼顯示如下信息[INFO] Scanning for projects...[WARNING][WARNING] Some problems were encountered while building the effective model fororg.apache.hadoop:hadoop-maven-plugins:maven-plugin:2.4.0[WARNING] 'build.plugins.plugin.(groupId:artifactId)' must be unique but found duplicate declaration of plugin org.apache.maven.plugins:maven-enforcer-plugin @org.apache.hadoop:hadoop-project:2.4.0, D:/hadoop2/hadoop-2.4.0-src/hadoop-project/pom.xml, line 1015, column 15[WARNING][WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.[WARNING][WARNING] For this reason, future Maven versions might no longer support building such malformed projects.[WARNING][INFO][INFO] Using the builder org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder with a thread count of 1[INFO][INFO] ------------------------------------------------------------------------[INFO] Building Apache Hadoop Maven Plugins 2.4.0[INFO] ------------------------------------------------------------------------[INFO][INFO] --- maven-antrun-plugin:1.7:run (create-testdirs) @ hadoop-maven-plugins---[INFO] Executing tasksmain:[INFO] Executed tasks[INFO][INFO] --- maven-plugin-plugin:3.0:descriptor (default-descriptor) @ hadoop-maven-plugins ---[INFO] Using 'UTF-8' encoding to read mojo metadata.[INFO] Applying mojo extractor for language: java-annotations[INFO] Mojo extractor for language: java-annotations found 2 mojo descriptors.[INFO] Applying mojo extractor for language: java[INFO] Mojo extractor for language: java found 0 mojo descriptors.[INFO] Applying mojo extractor for language: bsh[INFO] Mojo extractor for language: bsh found 0 mojo descriptors.[INFO][INFO] --- maven-resources-plugin:2.2:resources (default-resources) @ hadoop-maven-plugins ---[INFO] Using default encoding to copy filtered resources.[INFO][INFO] --- maven-compiler-plugin:2.5.1:compile (default-compile) @ hadoop-maven-plugins ---[INFO] Nothing to compile - all classes are up to date[INFO][INFO] --- maven-plugin-plugin:3.0:descriptor (mojo-descriptor) @ hadoop-maven-plugins ---[INFO] Using 'UTF-8' encoding to read mojo metadata.[INFO] Applying mojo extractor for language: java-annotations[INFO] Mojo extractor for language: java-annotations found 2 mojo descriptors.[INFO] Applying mojo extractor for language: java[INFO] Mojo extractor for language: java found 0 mojo descriptors.[INFO] Applying mojo extractor for language: bsh[INFO] Mojo extractor for language: bsh found 0 mojo descriptors.[INFO][INFO] --- maven-resources-plugin:2.2:testResources (default-testResources) @ hadoop-maven-plugins ---[INFO] Using default encoding to copy filtered resources.[INFO][INFO] --- maven-compiler-plugin:2.5.1:testCompile (default-testCompile) @ hadoop-maven-plugins ---[INFO] No sources to compile[INFO][INFO] --- maven-surefire-plugin:2.16:test (default-test) @ hadoop-maven-plugins---[INFO] No tests to run.[INFO][INFO] --- maven-jar-plugin:2.3.1:jar (default-jar) @ hadoop-maven-plugins ---[INFO] Building jar: D:/hadoop2/hadoop-2.4.0-src/hadoop-maven-plugins/target/hadoop-maven-plugins-2.4.0.jar[INFO][INFO] --- maven-plugin-plugin:3.0:addPluginArtifactMetadata (default-addPluginArtifactMetadata) @ hadoop-maven-plugins ---[INFO][INFO] --- maven-site-plugin:3.3:attach-descriptor (attach-descriptor) @ hadoop-maven-plugins ---[INFO][INFO] --- maven-install-plugin:2.3.1:install (default-install) @ hadoop-maven-plugins ---[INFO] Installing D:/hadoop2/hadoop-2.4.0-src/hadoop-maven-plugins/target/hadoop-maven-plugins-2.4.0.jar to C:/Users/hyj/.m2/repository/org/apache/hadoop/hadoop-maven-plugins/2.4.0/hadoop-maven-plugins-2.4.0.jar[INFO] Installing D:/hadoop2/hadoop-2.4.0-src/hadoop-maven-plugins/pom.xml to C:/Users/hyj/.m2/repository/org/apache/hadoop/hadoop-maven-plugins/2.4.0/hadoop-maven-plugins-2.4.0.pom[INFO] ------------------------------------------------------------------------[INFO] BUILD SUCCESS[INFO] ------------------------------------------------------------------------[INFO] Total time: 4.891 s[INFO] Finished at: 2014-06-23T14:47:33+08:00[INFO] Final Memory: 21M/347M[INFO] ------------------------------------------------------------------------復制代碼部分截圖如下:![]()
(2)運行mvn eclipse:eclipse -DskipTests復制代碼這時候注意,我們進入的是hadoop_home,我這里是D:/hadoop2/hadoop-2.4.0-src部分信息如下[INFO][INFO] ------------------------------------------------------------------------[INFO] Reactor Summary:[INFO][INFO] Apache Hadoop Main ................................ SUCCESS [ 0.684 s][INFO] Apache Hadoop Project POM ......................... SUCCESS [ 0.720 s][INFO] Apache Hadoop Annotations ......................... SUCCESS [ 0.276 s][INFO] Apache Hadoop Project Dist POM .................... SUCCESS [ 0.179 s][INFO] Apache Hadoop Assemblies .......................... SUCCESS [ 0.121 s][INFO] Apache Hadoop Maven Plugins ....................... SUCCESS [ 1.680 s][INFO] Apache Hadoop MiniKDC ............................. SUCCESS [ 1.802 s][INFO] Apache Hadoop Auth ................................ SUCCESS [ 1.024 s][INFO] Apache Hadoop Auth Examples ....................... SUCCESS [ 0.160 s][INFO] Apache Hadoop Common .............................. SUCCESS [ 1.061 s][INFO] Apache Hadoop NFS ................................. SUCCESS [ 0.489 s][INFO] Apache Hadoop Common Project ...................... SUCCESS [ 0.056 s][INFO] Apache Hadoop HDFS ................................ SUCCESS [ 2.770 s][INFO] Apache Hadoop HttpFS .............................. SUCCESS [ 0.965 s][INFO] Apache Hadoop HDFS BookKeeper Journal ............. SUCCESS [ 0.629 s][INFO] Apache Hadoop HDFS-NFS ............................ SUCCESS [ 0.284 s][INFO] Apache Hadoop HDFS Project ........................ SUCCESS [ 0.061 s][INFO] hadoop-yarn ....................................... SUCCESS [ 0.052 s][INFO] hadoop-yarn-api ................................... SUCCESS [ 0.842 s][INFO] hadoop-yarn-common ................................ SUCCESS [ 0.322 s][INFO] hadoop-yarn-server ................................ SUCCESS [ 0.065 s][INFO] hadoop-yarn-server-common ......................... SUCCESS [ 0.972 s][INFO] hadoop-yarn-server-nodemanager .................... SUCCESS [ 0.580 s][INFO] hadoop-yarn-server-web-proxy ...................... SUCCESS [ 0.379 s][INFO] hadoop-yarn-server-applicationhistoryservice ...... SUCCESS [ 0.281 s][INFO] hadoop-yarn-server-resourcemanager ................ SUCCESS [ 0.378 s][INFO] hadoop-yarn-server-tests .......................... SUCCESS [ 0.534 s][INFO] hadoop-yarn-client ................................ SUCCESS [ 0.307 s][INFO] hadoop-yarn-applications .......................... SUCCESS [ 0.050 s][INFO] hadoop-yarn-applications-distributedshell ......... SUCCESS [ 0.202 s][INFO] hadoop-yarn-applications-unmanaged-am-launcher .... SUCCESS [ 0.194 s][INFO] hadoop-yarn-site .................................. SUCCESS [ 0.057 s][INFO] hadoop-yarn-project ............................... SUCCESS [ 0.066 s][INFO] hadoop-mapreduce-client ........................... SUCCESS [ 0.091 s][INFO] hadoop-mapreduce-client-core ...................... SUCCESS [ 1.321 s][INFO] hadoop-mapreduce-client-common .................... SUCCESS [ 0.786 s][INFO] hadoop-mapreduce-client-shuffle ................... SUCCESS [ 0.456 s][INFO] hadoop-mapreduce-client-app ....................... SUCCESS [ 0.508 s][INFO] hadoop-mapreduce-client-hs ........................ SUCCESS [ 0.834 s][INFO] hadoop-mapreduce-client-jobclient ................. SUCCESS [ 0.541 s][INFO] hadoop-mapreduce-client-hs-plugins ................ SUCCESS [ 0.284 s][INFO] Apache Hadoop MapReduce Examples .................. SUCCESS [ 0.851 s][INFO] hadoop-mapreduce .................................. SUCCESS [ 0.099 s][INFO] Apache Hadoop MapReduce Streaming ................. SUCCESS [ 0.742 s][INFO] Apache Hadoop Distributed Copy .................... SUCCESS [ 0.335 s][INFO] Apache Hadoop Archives ............................ SUCCESS [ 0.397 s][INFO] Apache Hadoop Rumen ............................... SUCCESS [ 0.371 s][INFO] Apache Hadoop Gridmix ............................. SUCCESS [ 0.230 s][INFO] Apache Hadoop Data Join ........................... SUCCESS [ 0.184 s][INFO] Apache Hadoop Extras .............................. SUCCESS [ 0.217 s][INFO] Apache Hadoop Pipes ............................... SUCCESS [ 0.048 s][INFO] Apache Hadoop OpenStack support ................... SUCCESS [ 0.244 s][INFO] Apache Hadoop Client .............................. SUCCESS [ 0.590 s][INFO] Apache Hadoop Mini-Cluster ........................ SUCCESS [ 0.230 s][INFO] Apache Hadoop Scheduler Load Simulator ............ SUCCESS [ 0.650 s][INFO] Apache Hadoop Tools Dist .......................... SUCCESS [ 0.334 s][INFO] Apache Hadoop Tools ............................... SUCCESS [ 0.042 s][INFO] Apache Hadoop Distribution ........................ SUCCESS [ 0.144 s][INFO] ------------------------------------------------------------------------[INFO] BUILD SUCCESS[INFO] ------------------------------------------------------------------------[INFO] Total time: 31.234 s[INFO] Finished at: 2014-06-23T14:55:08+08:00[INFO] Final Memory: 84M/759M[INFO] ------------------------------------------------------------------------復制代碼這時候,我們已經把源碼給下載下來了。這時候,我們會看到文件會明顯增大。
3.關聯eclipse源碼加入我們以下程序
hadoop2.2mapreduce例子.rar (1.14 MB, 下載次數: 68, 售價: 1 云幣) 如下圖示,對他們進行了打包
這兩個文件, MaxTemperature.zip為mapreduce例子,mockito-core-1.8.5.jar為mapreduce例子所引用的包(這里需要說明的是,mapreduce為2.2,但是不影響關聯源碼,只是交給大家該如何關聯源碼)我們解壓之后,導入eclipse(對于導入項目不熟悉,參考零基礎教你如何導入eclipse項目)
我們導入之后,看到很多的紅線,這些其實都是沒有引用包,下面我們開始解決這些語法問題。一、解決導入jar包(1)引入mockito-core-1.8.5.jar(2)hadoop2.4編譯包中的jar文件,這些文件的位置如下:hadoop_home中share/hadoop文件夾下,具體我這的位置D:/hadoop2/hadoop-2.4.0/share/hadoop找到里面的jar包,舉例如下:lib文件中的jar包,以及下面的jar包都添加到buildpath中。如果對于引用包,不知道該如何添加這些jar包,參考hadoop開發方式總結及操作指導。(注意的是,我們這里是引入的是編譯包,編譯的下載hadoop--642.4.0.tar.gz鏈接: http://pan.baidu.com/s/1c0vPjG0 密碼:xj6l)更多包下載可以參考hadoop家族、strom、spark、linux、flume等jar包、安裝包匯總下載
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二、關聯源碼1.我們導入jar包之后,就沒有錯誤了,如下圖所示
2.找不到源碼當我們想看一個類或則函數怎么實現的時候,通過Open Call Hierarchy,卻找不到源文件。
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3.Attach Source
上面三處,我們按照順序添加即可,我們選定壓縮包之后,單擊確定,ok了,我們的工作已經完畢。注意:對于hadoop-2.2.0-src.zip則是我們上面通過maven下載的源碼,然后壓縮的文件,記得一定是壓縮文件zip的形式4.驗證關聯后查看源碼我們再次執行上面操作,通過Open Call Hierarchy看到下面內容
然后我們雙擊上圖主類,即紅字部分,我們看到下面內容:
問題:細心的同學,這里面我們產生一個問題,因為我們看到的是.class文件,而不是.java文件。那么他會不會和我們所看到的.java文件不一樣那。其實是一樣的,感興趣的同學,可以驗證一下。
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