1.在class注解上@ControllerAdvice
2.在方法上注解上@ExceptionHandler(value = Exception.class)
3.如果返回的是View，方法的返回值是ModelAndView；如果返回的是String或者是Json数据，那么需要在方法上添加@ResponseBody注解.
例：@ControllerAdvice
public class GlobalDefaultExceptionHandler{
@ExceptionHandler(value = Exception.class)
public void defaultErrorHandler(HttpServletRequest req, Exception e) {
return "服务器繁忙"
}
}
修改application.properties文件server配置：
#server.port=8080
#server.address= # bind to a specific NIC
#server.session-timeout= # session timeout in seconds
#the context path, defaults to '/'
#server.context-path=/spring-boot
#server.servlet-path= # the servlet path, defaults to '/'
#server.tomcat.access-log-pattern= # log pattern of the access log
#server.tomcat.access-log-enabled=false # is access logging enabled
#server.tomcat.protocol-header=x-forwarded-proto # ssl forward headers
#server.tomcat.remote-ip-header=x-forwarded-for
#server.tomcat.basedir=/tmp # base dir (usually not needed, defaults to tmp)
#server.tomcat.background-processor-delay=30; # in seconds
#server.tomcat.max-threads = 0 # number of threads in protocol handler
#server.tomcat.uri-encoding = UTF-8 # character encoding to use for URL decoding