线程"main"中的异常java.lang.NoClassDefFoundError:

问题描述

我正在尝试运行Java程序，并且遇到以下运行时错误.错误显示如下.

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/http/params/SyncBasicHttpParams
    at org.apache.http.impl.client.DefaultHttpClient.createHttpParams(DefaultHttpClient.java:157)
    at org.apache.http.impl.client.AbstractHttpClient.getParams(AbstractHttpClient.java:448)
    at org.apache.http.impl.client.AbstractHttpClient.createClientConnectionManager(AbstractHttpClient.java:309)
    at org.apache.http.impl.client.AbstractHttpClient.getConnectionManager(AbstractHttpClient.java:466)
    at org.apache.http.impl.client.AbstractHttpClient.createHttpContext(AbstractHttpClient.java:286)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:851)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:805)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:784)
    at net.floodlightcontroller.core.internal.PacketStreamerClient.registerForPackets(PacketStreamerClient.java:90)
    at net.floodlightcontroller.core.internal.PacketStreamerClient.main(PacketStreamerClient.java:51)
Caused by: java.lang.ClassNotFoundException: org.apache.http.params.SyncBasicHttpParams
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 10 more

错误是java.lang.NoClassDefFoundError

现在NoClassDefFoundError的明显原因是某个特定的类在Classpath中不可用，因此我们需要将该类添加到Classpath中，或者如果我们期望它可以在Classpath中检查为什么它不可用. /p>

现在，我添加到类路径中的文件如下.

export CLASSPATH=$(JARS=(./lib/*.jar); IFS=:; echo "${JARS[*]}")
export CLASSPATH=$CLASSPATH:~/.m2/repository/org/apache/httpcomponents/httpclient/4.0.1/httpclient-4.0.1.jar
export CLASSPATH=$CLASSPATH:~/.m2/repository/org/apache/httpcomponents/httpcore/4.0.1/httpcore-4.0.1.jar
export CLASSPATH=$CLASSPATH:~/.m2/repository/commons-logging/commons-logging/1.1.1/commons-logging-1.1.1.jar
export CLASSPAHT=$CLASSPATH:~/ms_thesis/ONOS/httpcore-4.1.jar
#export CLASSPATH=$CLASSPATH:~/ms_thesis/ONOS/lib/httpclient-4.2.jar
export CLASSPATH=$CLASSPATH:~/google-gson-2.2.4/gson-2.2.4.jar

我应该添加哪个jar文件来查找"org/apache/http/params/SyncBasicHttpParams"，我对Java还是很陌生，不知道如何调试此问题.

解决方案

org/apache/http/params/SyncBasicHttpParams类在httpcore-4.1-alpha1.jar下，可以从

下载.

http://mirrors.ibiblio.org/pub/mirrors/maven2/org/apache/httpcomponents/httpcore/4.1-alpha1/httpcore-4.1-alpha1.jar

将来，如果您需要为一个类找到一个jar，则可以使用此链接，这通常会有所帮助:

http://www.findjar.com/

I am trying to run a java program and I am getting the following run time error.The error is shown below.

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/http/params/SyncBasicHttpParams
    at org.apache.http.impl.client.DefaultHttpClient.createHttpParams(DefaultHttpClient.java:157)
    at org.apache.http.impl.client.AbstractHttpClient.getParams(AbstractHttpClient.java:448)
    at org.apache.http.impl.client.AbstractHttpClient.createClientConnectionManager(AbstractHttpClient.java:309)
    at org.apache.http.impl.client.AbstractHttpClient.getConnectionManager(AbstractHttpClient.java:466)
    at org.apache.http.impl.client.AbstractHttpClient.createHttpContext(AbstractHttpClient.java:286)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:851)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:805)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:784)
    at net.floodlightcontroller.core.internal.PacketStreamerClient.registerForPackets(PacketStreamerClient.java:90)
    at net.floodlightcontroller.core.internal.PacketStreamerClient.main(PacketStreamerClient.java:51)
Caused by: java.lang.ClassNotFoundException: org.apache.http.params.SyncBasicHttpParams
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 10 more

The error is java.lang.NoClassDefFoundError

Now the Obvious reason of NoClassDefFoundError is that a particular class is not available in Classpath, so we need to add that into Classpath or we need to check why it’s not available in Classpath if we are expecting it to be.

Now the files that I have added to the classpath are the following.

export CLASSPATH=$(JARS=(./lib/*.jar); IFS=:; echo "${JARS[*]}")
export CLASSPATH=$CLASSPATH:~/.m2/repository/org/apache/httpcomponents/httpclient/4.0.1/httpclient-4.0.1.jar
export CLASSPATH=$CLASSPATH:~/.m2/repository/org/apache/httpcomponents/httpcore/4.0.1/httpcore-4.0.1.jar
export CLASSPATH=$CLASSPATH:~/.m2/repository/commons-logging/commons-logging/1.1.1/commons-logging-1.1.1.jar
export CLASSPAHT=$CLASSPATH:~/ms_thesis/ONOS/httpcore-4.1.jar
#export CLASSPATH=$CLASSPATH:~/ms_thesis/ONOS/lib/httpclient-4.2.jar
export CLASSPATH=$CLASSPATH:~/google-gson-2.2.4/gson-2.2.4.jar

What jar file should I add to find "org/apache/http/params/SyncBasicHttpParams" I am very new to java and don't know how to debug this issue.

解决方案

org/apache/http/params/SyncBasicHttpParams class is under httpcore-4.1-alpha1.jar , which can be downloaded from

http://mirrors.ibiblio.org/pub/mirrors/maven2/org/apache/httpcomponents/httpcore/4.1-alpha1/httpcore-4.1-alpha1.jar

In future if you need to find a jar for a class, then you can use this link, this is generally helpful:

http://www.findjar.com/

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