<dependency>
   <groupId>net.sf.json-lib</groupId>
   <artifactId>json-lib</artifactId>
   <version>2.4</version>
   <classifier>jdk15</classifier>
</dependency> 
修改为

<dependency>
   <groupId>net.sf.json-lib</groupId>
   <artifactId>json-lib</artifactId>
   <version>2.1</version>
   <classifier>jdk15</classifier>
</dependency>