JWT（JSON Web Token）用户认证

1、颁发token

<!--JWT依赖--><dependency><groupId>io.jsonwebtoken</groupId><artifactId>jjwt</artifactId><version>0.9.1</version></dependency><dependency><groupId>javax.xml.bind</groupId><artifactId>jaxb-api</artifactId><version>2.3.1</version><scope>provided</scope></dependency>

2、新建类