Filter in Java

Filter Operating Principle

When the client sends a request for Web resources, the Web server checks based on the filtering rules set in the application configuration file. If the customer request meets the filtering rules, the client requests/responses are intercepted, check or modify request headers and data, use the filter chain in sequence, and finally send the request/response to the requested Web resource for processing. The request information can be modified in the filter chain, or the request cannot be sent to the resource processor based on the condition, and a response can be sent directly to the client. After the resource processor completes processing the resource, the response information is returned in reverse order. In this process, you can modify the response information to complete certain tasks.