錯誤異常

ERROR com.mdd.documentary.exception.GlobalExceptionHandler - org.springframework.web.util.NestedServletException: Handler dispatch failed; nested exception is java.lang.NoClassDefFoundError: org/apache/http/entity/mime/MultipartEntityBuilder
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1055)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
        at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
        at com.github.xiaoymin.knife4j.spring.filter.ProductionSecurityFilter.doFilter(ProductionSecurityFilter.java:53)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
        at com.github.xiaoymin.knife4j.spring.filter.SecurityBasicAuthFilter.doFilter(SecurityBasicAuthFilter.java:90)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.

首先，先了解一下java.lang.ClassNotFoundException。NoClassDefFoundError錯誤的發(fā)生司倚，是因為Java虛擬機(jī)在編譯時能找到合適的類铝侵，而在運(yùn)行時不能找到合適的類導(dǎo)致的錯誤。例如在運(yùn)行時我們想調(diào)用某個類的方法或者訪問這個類的靜態(tài)成員的時候锄码，發(fā)現(xiàn)這個類不可用夺英，此時Java虛擬機(jī)就會拋出NoClassDefFoundError錯誤晌涕。與ClassNotFoundException的不同在于，這個錯誤發(fā)生只在運(yùn)行時需要加載對應(yīng)的類不成功痛悯，而不是編譯時發(fā)生余黎。很多Java開發(fā)者很容易在這里把這兩個錯誤搞混。

錯誤原因：

了解了java.lang.ClassNotFoundException錯誤的原因载萌，就大致了解此問題大致所在了惧财，就是缺少了 httpmime.jar這個包。

問題解決：

Maven增加如下依賴

<dependency>
  <groupId>org.apache.httpcomponents</groupId>
  <artifactId>httpmime</artifactId>
  <version>4.3.2</version>
</dependency>

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