今天在用struts2就行文件下载时出现如下错误: Servlet.service() for servlet default threw exception java.lang.IllegalArgumentException: Can not find a java.io.InputStream with the name [imageStream] in the invocation stack. Check the <param name="inputName">
Java读写锁,ReadWriteLock.java接口, RentrantReadWriteLock.java实现.通过读写锁,可以实现读-读线程并发,读-写,写-读线程互斥进行.以前面试遇到一个问题,ConcurrentHashMap的实现原理,如何封装Map效率更高.今天看了<Java并发编程实战>,封装的ReadWriteMap类,效率就比ConcurrentHashMap效率更高,在读多写少的场景. ReadWriteMap.java public class ReadWriteMa
1.错误描写叙述 八月 14, 2015 4:22:45 下午 com.opensymphony.xwork2.util.logging.jdk.JdkLogger error 严重: Exception occurred during processing request: Can not find a java.io.InputStream with the name [downloadFile] in the invocation stack. Check the <param name=