java后台解决跨域问题

一种是同源策略：
IP相同 协议相同 端口相同
这种是过滤器：
import org.springframework.stereotype.Component;

import javax.servlet.*;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Component
public class SimpleCORSFilter implements Filter {

//解决跨域问题
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
    HttpServletResponse response = (HttpServletResponse) res;
    response.setHeader("Access-Control-Allow-Origin", "*");
    response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE,PUT");
    response.setHeader("Access-Control-Max-Age", "3600");
    response.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");

    chain.doFilter(req, res);
}

public void init(FilterConfig filterConfig) {}

public void destroy() {}

}