javax.servlet.ServletException：java.lang.NoClassDefFoundError：org / apache / http / HttpRequest错误

Question

调用Servlet时出现此错误。但是，我这样做在我的httpclient-4.5.7.jar文件夹中有WEB-INF/lib个文件。 Tomcat还要我做什么？

编辑：

org.apache.jasper.JasperException: javax.servlet.ServletException: java.lang.NoClassDefFoundError: org/apache/http/HttpRequest
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:549)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:455)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    com.web.RedditUserInfo.doPost(RedditUserInfo.java:45)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause

javax.servlet.ServletException: java.lang.NoClassDefFoundError: org/apache/http/HttpRequest
    org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:916)
    org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:845)
    org.apache.jsp.user_005fview_jsp._jspService(user_005fview_jsp.java:319)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    com.web.RedditUserInfo.doPost(RedditUserInfo.java:45)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause

java.lang.NoClassDefFoundError: org/apache/http/HttpRequest
    java.lang.ClassLoader.defineClass1(Native Method)
    java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2957)
    org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1210)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1690)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1571)
    main.RedditParser.getAccessToken(RedditParser.java:61)
    main.RedditParser.<init>(RedditParser.java:43)
    org.apache.jsp.user_005fview_jsp._jspService(user_005fview_jsp.java:166)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    com.web.RedditUserInfo.doPost(RedditUserInfo.java:45)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause

java.lang.ClassNotFoundException: org.apache.http.HttpRequest
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1720)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1571)
    java.lang.ClassLoader.defineClass1(Native Method)
    java.lang.ClassLoader.defineClass(ClassLoader.java:760)
    java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2957)
    org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1210)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1690)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1571)
    main.RedditParser.getAccessToken(RedditParser.java:61)
    main.RedditParser.<init>(RedditParser.java:43)
    org.apache.jsp.user_005fview_jsp._jspService(user_005fview_jsp.java:166)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    com.web.RedditUserInfo.doPost(RedditUserInfo.java:45)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

编辑：

我添加了httpcore-4.2.1.jar，现在我得到了：

javax.servlet.ServletException: java.lang.NoClassDefFoundError: org/apache/http/config/Lookup错误。