1.在项目pom文件中配置

 <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
        </dependency>

2.创建user

public class User implements Principal {

    private final String name;

    public User(String name) {
        this.name = name;
    }

    @Override