Solution to running errors in standalone mode in Hadoop Quick Start

I tried Hadoop and did not expect to follow the tutorial. The first example reported an error ...... Error: $ binhadoopjarhadoop-mapred-examples-0.21.0.jargrepinputoutputdfs [a-z.] + Exceptioninthreadmainjava. io. IOException: erropeningjobjar: hadoop-mapred-ex

I tried Hadoop and did not expect to follow the tutorial. The first example reported an error ......

The error is as follows:

$ Bin/hadoop jar hadoop-maprEd-ExAmples-0.21.0.jarGrepInput output'DfS [a-z.] +'

Exception in thread "main" java. io. IOException: Error opening job jar: hadoop-mapred-examples-0.21.0.jar

At org. apache. hadoop. util. RunJar. main (RunJar. java: 90)

CauSedBy: java. util.Zip. ZipException: error in opening zipFile

At java.util.zip. ZipFile. open (Native Method)

At java.util.zip. ZipFile. (ZipFile. java: 127)

At java. util. jar. JarFile. (JarFile. java: 135)

At java. util. jar. JarFile. (JarFile. java: 72)

At org. apache. hadoop. util. RunJar. main (RunJar. java: 88)

A closer look, java.util.zip. ZipException is an exception that cannot be found in the file. The main reason is that the hadoop-mapred-examples-0.21.0.jar cannot be located. The solution is very simple.

1) configure the environment variables first (if you are operating in the hadoop home directory, you can try it)

$ Vim/etc/profile

Add these two rows

ExportHADOOP_HOME =/home/linrui/programfiles/dev/hadoop-0.20.203.0

Export HADOOP_CONF_DIR = $ HADOOP_HOME/conf

2) Go To The hadoop_home directory and check the jar package (this package exists, but the name may not be the same). Then write the name accurately.

Then run ~ Everything is OK!