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javac compiling error ( mising package)

javac 编译java源文件时，提示 package does not exist 的错误

Test.java

import java.security.MessageDigest;
import org.apache.commons.codec.binary.Hex;
 
public class Test{
    public static void main(String args[]){
        boolean isAlarmed = true;
        boolean aa = isAlarmed || false;
        String queryTimestamp = "1970-01-01T00:00:00+0000";
        System.out.println(queryTimestamp.getBytes());
        try{
            MessageDigest md5 = MessageDigest.getInstance("MD5");
            System.out.println(md5.digest("stringtodigest".getBytes()));
 
            byte[] value = "stringtodigest".getBytes();
            md5.update(value);
            byte[] digest = md5.digest();
            System.out.println(new String(Hex.encodeHex(digest)));
     
 
            System.out.println(md5.digest("stringtodigest".getBytes())); 
            System.out.println(md5.digest("stringtodigest".getBytes()));
        }catch(Exception e){ 
     
        }   
    }   
}

　　javac Test.java编译的时候报错！

解决办法：

　　1. 到mvn repository(http://mvnrepository.com/artifact/commons-codec/commons-codec/1.7)上面吧缺少的 jar 包下载下来，

　　2. 然后给 CLASSPATH 环境变量在添加一下这个jar 包所在的路径，就可以了。

---------------------------------------------------------------------------------------

参考：https://www.linuxquestions.org/questions/programming-9/javac-compiling-error-mising-package-669775/

javac compiling error ( mising package)

First i have to say I am very new to java. I downloaded java codes from the Internet and try to compile them using javac. I got following error,
Code:

C:\temp\javacrypt>"C:\Program Files\Java\jdk1.6.0_06\bin\javac" RSAExample.java
.\BaseCrypto.java:1: package org.apache.commons.codec does not exist
import org.apache.commons.codec.DecoderException;
                               ^
.\BaseCrypto.java:2: package org.apache.commons.codec.binary does not exist
import org.apache.commons.codec.binary.Hex;
                                      ^
.\BaseCrypto.java:26: cannot find symbol
symbol  : class DecoderException
location: class BaseCrypto
    public static byte[] asByte(String hexString) throws DecoderException {
                                                         ^
.\BaseCrypto.java:16: cannot find symbol
symbol  : variable Hex
location: class BaseCrypto
        return new String(Hex.encodeHex(buf));
                          ^
.\BaseCrypto.java:27: cannot find symbol
symbol  : variable Hex
location: class BaseCrypto
        return Hex.decodeHex(hexString.toCharArray());
               ^
5 errors

　　I guess i just missed some packages like "org.apache.commons.codec.*",
　　and that package is not part of standard jdk, right?

　　How do i get those package? I also have netbean and eclipse, but I haven't tried to use them yet.

　　-----------------

When you get the package, which is probably a .jar file, add that .jar file to your classpath (environment variable).

EDIT: Specifically, here.

EDIT: I believe on Windows it's something like...

SET CLASSPATH=%CLASSPATH%;C:\path\to\jar\jarfile.jar

----------------------

I downloaded the jar file suggested by elprawn, and it work great!! thank you so much.
I am curious about the suggestion from jay73. Is the package management the software like "yum" or "apt-get", right? What keyword should use to search for it?

----------------------

On a system that uses apt, you can use
aptitude search commons
and you'should get a list of the available commons libraries.On ubuntu:

jurgen@Selena:~$ aptitude search commons
i libcommons-attributes-java - adds C#/.Net-style attributes to Java code
i A libcommons-beanutils-java - utility for manipulating JavaBeans 
i libcommons-beanutils-java-doc - Javadoc API for libcommons-beanutils-java 
i A libcommons-cli-java - API for working with the command line argu
i A libcommons-codec-java - encoder and decoders such as Base64 and he
i A libcommons-collections-java - A set of abstract data type interfaces and
i A libcommons-collections3-java - A set of abstract data type interfaces and
i libcommons-collections3-java-do - Documentation for libcommons-collections3-
i libcommons-configuration-java - Java based library providing a generic con
p libcommons-csv-java - a Java library for working with csv (comma
p libcommons-csv-java-doc - documentation for libcommons-csv-java 
i A libcommons-daemon-java - library to launch Java applications as dae
i A libcommons-dbcp-java - Database Connection Pooling Services 
i A libcommons-digester-java - Rule based XML Java object mapping tool 
p libcommons-discovery-java - locates classes that implement a given Jav
i A libcommons-el-java - Implementation of the JSP2.0 Expression La
i libcommons-fileupload-java - File upload capability to your servlets an
i libcommons-httpclient-java - A Java(TM) library for creating HTTP clien
i libcommons-httpclient-java-doc - Documentation for libcommons-httpclient-ja
i libcommons-io-java - Common useful IO related classes 
i libcommons-io-java-doc - Common useful IO related classes - documen
p libcommons-jexl-java - expression language engine 
p libcommons-jxpath-java - manipulate javabean using XPath syntax 
p libcommons-jxpath-java-doc - Javadoc API for libcommons-jxpath-java 
i A libcommons-lang-java - Extension of the java.lang package
i A libcommons-launcher-java - cross platform java application launcher 
i A libcommons-logging-java - commmon wrapper interface for several logg
i A libcommons-modeler-java - convenience library to use Java Management
i libcommons-modeler-java-doc - documentation and examples for Commons Mod
i libcommons-net-java - internet protocol suite Java library 
p libcommons-openpgp-java - a common and simple interface for generati
p libcommons-openpgp-java-doc - a common and simple interface for generati
i A libcommons-pool-java - pooling implementation for Java objects 
i libcommons-validator-java - ease and speed development and maintenance
p libgettext-commons-java - Java classes for internationalization (i18
p libhibernate-commons-annotation - Hibernate Commons Annotations 
p libws-commons-util-java - Common utilities from the Apache Web Servi
p libxml-commons-resolver1.1-java - XML entity and URI resolver library 
p libxml-commons-resolver1.1-java - XML entity and URI resolver library -- doc
p libxml-commons-resolver1.1-java - XML entity and URI resolver library -- nat
i libxmlgraphics-commons-java - reusable components used by Batik and FOP