What can be done through Java annotation in the Web framework

In the Web framework, Java annotation can be used to do the following things: 1. URL mapping: Annotations can be used to map the requested URL to a specific method. Commonly used annotations include '@ GetMapping', '@ PostMapping', and so on. @RestController @RequestMapping("/api") public class ApiController { @GetMapping("/hello") public String hello() { return "Hello World!"; } } 2. Parameter binding: Annotations can be used to bind request parameters to method parameters. Commonly used annotations include '@ RequestParam', '@ PathVariable', etc. @RestController @RequestMapping("/api") public class ApiController { @GetMapping("/user") public String getUser(@RequestParam("id") int userId) { //Obtain user information based on ID return "User: " + userId; } } 3. Request Body Binding: Annotations can be used to bind the request body to the parameters of the method. The commonly used annotations are '@ RequestBody'. @RestController @RequestMapping("/api") public class ApiController { @PostMapping("/user") public String createUser(@RequestBody User user) { //Create User return "User Created: " + user.getName(); } } 4. Request filtering: Annotations can be used to add request filtering functionality. Commonly used annotations include '@ WebFilter', '@ Order', etc. @WebFilter(urlPatterns = "/*") public class ExampleFilter implements Filter { @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { //Perform request filtering operations chain.doFilter(request, response); } } Summary: Java annotation provide a convenient way to complete URL mapping, parameter binding, request body binding, request filtering and other operations in the Web framework. Using annotations can make the code more concise and clear, and improve development efficiency. However, when using annotations, it is also important to pay attention to their rational use to avoid excessive and complex annotations that can lead to a decrease in code readability.