What method is used to solve cross-domain problems in java

Solving cross-origin issues in Java usually involves setting appropriate CORS (Cross-Origin Resource Sharing) headers. The following are specific methods and examples of using Spring Framework to solve cross-domain problems:

Suppose you have a Spring Boot application with a controller handling data requests. You need to allow pages under other domain names to access this interface.

1. Use @CrossOriginannotations:

   @CrossOriginAnnotations can be applied directly to controller methods to specify domains that allow cross-domain requests. Here is an example:

   import org.springframework.web.bind.annotation.CrossOrigin;
   import org.springframework.web.bind.annotation.GetMapping;
   import org.springframework.web.bind.annotation.RestController;
   
   @RestController
   public class DataController {
         
         
       @CrossOrigin(origins = "http://example.com")
       @GetMapping("/data")
       public String getData() {
         
         
           return "This is some data from the server.";
       }
   }
   

   In the example above, only http://example.compages from the domain can access /datathe interface.

2. Use global CORS configuration:

   You can also configure CORS globally in your application's configuration to allow cross-origin requests for all or specific domains. Create a configuration class, configure CorsRegistrythe object, as follows:

   import org.springframework.context.annotation.Configuration;
   import org.springframework.web.servlet.config.annotation.CorsRegistry;
   import org.springframework.web.servlet.config.annotation.EnableWebMvc;
   import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
   
   @Configuration
   @EnableWebMvc
   public class CorsConfig implements WebMvcConfigurer {
         
         
       @Override
       public void addCorsMappings(CorsRegistry registry) {
         
         
           registry.addMapping("/data")
                   .allowedOrigins("http://example.com")
                   .allowedMethods("GET"); // 允许的请求方法
       }
   }
   

   The above example will allow http://example.compages from the domain to access /datathe interface, and only allow GET requests.

3. Use a filter or interceptor:

   You can write a custom filter or interceptor to set the appropriate CORS headers in the response. This way, you can reuse the same cross-origin setup logic in multiple places in your application.

   import javax.servlet.Filter;
   import javax.servlet.FilterChain;
   import javax.servlet.FilterConfig;
   import javax.servlet.ServletException;
   import javax.servlet.ServletRequest;
   import javax.servlet.ServletResponse;
   import javax.servlet.annotation.WebFilter;
   import java.io.IOException;
   
   @WebFilter("/*")
   public class CorsFilter implements Filter {
         
         
       @Override
       public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
               throws IOException, ServletException {
         
         
           response.setHeader("Access-Control-Allow-Origin", "http://example.com");
           response.setHeader("Access-Control-Allow-Methods", "GET");
           chain.doFilter(request, response);
       }
   
       @Override
       public void init(FilterConfig filterConfig) throws ServletException {
         
         
       }
   
       @Override
       public void destroy() {
         
         
       }
   }
   

With the above methods, you can solve cross-domain issues in Java Spring Boot applications. Choosing the right method for your project depends on your application architecture and requirements.