我想在a中显示值HashMap.A HashMap可能有重复的值(但不是重复键),但我想只显示一次值.
所以我应该找到是否Map有重复的值.我知道我们可以迭代Map并使用返回布尔值map.containsValue(value).我想知道是否有任何方法可以在map中找到重复值,或者我自己应该编写代码？
我正在尝试一对一的JPA注释.但得到以下错误
Exception in thread "main" java.lang.IncompatibleClassChangeError: class org.hibernate.cfg.ExtendedMappings has interface org.hibernate.cfg.Mappings as super class
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(Unknown Source)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.defineClass(Unknown Source)
at java.net.URLClassLoader.access$000(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at org.hibernate.cfg.AnnotationConfiguration.createExtendedMappings(AnnotationConfiguration.java:182)
at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:272)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1377)
at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:859)
at com.HiberAnnJS.main(HiberAnnJS.java:21)
我不知道自己要做什么.