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这是一条镜像帖。来源：北邮人论坛 / java / #49495同步于 2016/4/19
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JAVA WEB工程中使用httpclient函数报错

BUPT2012
2016/4/19镜像同步3 回复
我在一个java web的工程里面要用REST API获取数据，然后就用了httpclient包来实现。 问题是我在写好的类里面使用main函数调试，没有错正确运行，但是在整个工程里面调用这个类中的函数就会报错。 报错信息如下： 严重: StandardWrapper.Throwable java.lang.NoSuchFieldError: INSTANCE at org.apache.http.impl.io.DefaultHttpRequestWriterFactory.<init>(DefaultHttpRequestWriterFactory.java:52) at org.apache.http.impl.io.DefaultHttpRequestWriterFactory.<init>(DefaultHttpRequestWriterFactory.java:56) at org.apache.http.impl.io.DefaultHttpRequestWriterFactory.<clinit>(DefaultHttpRequestWriterFactory.java:46) at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.<init>(ManagedHttpClientConnectionFactory.java:82) at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.<init>(ManagedHttpClientConnectionFactory.java:95) at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.<init>(ManagedHttpClientConnectionFactory.java:104) at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.<clinit>(ManagedHttpClientConnectionFactory.java:62) at org.apache.http.impl.conn.PoolingHttpClientConnectionManager$InternalConnectionFactory.<init>(PoolingHttpClientConnectionManager.java:572) at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.<init>(PoolingHttpClientConnectionManager.java:174) at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.<init>(PoolingHttpClientConnectionManager.java:158) at org.apache.http.impl.client.HttpClientBuilder.build(HttpClientBuilder.java:973) at com.tdrouting.util.GetDeviceInfo.getDeviceInfo(GetDeviceInfo.java:31) at com.tdrouting.util.CollectionTask.beginTask(CollectionTask.java:24) at com.tdrouting.util.MyServlet.init(MyServlet.java:24) at javax.servlet.GenericServlet.init(GenericServlet.java:212) at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1213) at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1026) at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4451) at org.apache.catalina.core.StandardContext.start(StandardContext.java:4768) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1061) at org.apache.catalina.core.StandardHost.start(StandardHost.java:822) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1061) at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463) at org.apache.catalina.core.StandardService.start(StandardService.java:525) at org.apache.catalina.core.StandardServer.start(StandardServer.java:759) at org.apache.catalina.startup.Catalina.start(Catalina.java:595) 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 org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414) 四月 19, 2016 7:42:49 下午 org.apache.catalina.core.StandardContext loadOnStartup 严重: Servlet /neteye threw load() exception java.lang.NoSuchFieldError: INSTANCE at org.apache.http.impl.io.DefaultHttpRequestWriterFactory.<init>(DefaultHttpRequestWriterFactory.java:52) at org.apache.http.impl.io.DefaultHttpRequestWriterFactory.<init>(DefaultHttpRequestWriterFactory.java:56) at org.apache.http.impl.io.DefaultHttpRequestWriterFactory.<clinit>(DefaultHttpRequestWriterFactory.java:46) at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.<init>(ManagedHttpClientConnectionFactory.java:82) at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.<init>(ManagedHttpClientConnectionFactory.java:95) at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.<init>(ManagedHttpClientConnectionFactory.java:104) at org.apache.http.impl.conn.ManagedHttpClientConnectionFactory.<clinit>(ManagedHttpClientConnectionFactory.java:62) at org.apache.http.impl.conn.PoolingHttpClientConnectionManager$InternalConnectionFactory.<init>(PoolingHttpClientConnectionManager.java:572) at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.<init>(PoolingHttpClientConnectionManager.java:174) at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.<init>(PoolingHttpClientConnectionManager.java:158) at org.apache.http.impl.client.HttpClientBuilder.build(HttpClientBuilder.java:973) at com.tdrouting.util.GetDeviceInfo.getDeviceInfo(GetDeviceInfo.java:31) at com.tdrouting.util.CollectionTask.beginTask(CollectionTask.java:24) at com.tdrouting.util.MyServlet.init(MyServlet.java:24) at javax.servlet.GenericServlet.init(GenericServlet.java:212) at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1213) at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1026) at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4451) at org.apache.catalina.core.StandardContext.start(StandardContext.java:4768) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1061) at org.apache.catalina.core.StandardHost.start(StandardHost.java:822) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1061) at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463) at org.apache.catalina.core.StandardService.start(StandardService.java:525) at org.apache.catalina.core.StandardServer.start(StandardServer.java:759) at org.apache.catalina.startup.Catalina.start(Catalina.java:595) 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 org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414) 求大神解答。。。卡在这好几天了。
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3 条回复
nuanyangyang机器人#1 · 2016/4/19
检查版本。
BUPT2012机器人#2 · 2016/4/19
感谢暖神回答。确实跟这个有关系，在网上查到报这个错误一般是导入的包有冲突。 查了下引入的包里面的确是既有commons-httpclient和httpclient-4.5。 问题是我把commons-httpclient包remove掉后，还是报错，没办法，我只好删了httpclient包，然后用commons-httpclient中旧的函数实现，这个时候没错误了。 为什么我remove了commons-httpclient包后还有错，是不是因为apache server中有用到？apache版本是6…… 现在就想还是用httpclient中的函数来实现，有什么办法吗？ 【 在 nuanyangyang 的大作中提到: 】 : 检查版本。
nuanyangyang机器人#3 · 2016/4/19
看看这个有没有帮助 http://stackoverflow.com/questions/13672884/httpclient-on-tomcat 另外，用tomcat-8.0.33试试看呢？6太老了吧。。。Apache已经宣布其死期是今年年底了。