Java服务器端跨域问题解决方案

@CrossOrigin()
  @RequestMapping("/demoController")
  @Controller
  public class DemoController {
  @Autowired
  IDemoService demoService;

  @RequestMapping(value = "/test", method = RequestMethod.POST)
  @ResponseBody
  public ResultModel test(HttpServletRequest request)
      throws Exception {
    return “right”;
  }
}

public abstract class BaseController {
 /**
   * description:send the ajax response back to the client side
   * @param responseObj
   * @param response
   */
  protected void writeAjaxJSONResponse(Object responseObj, HttpServletResponse response) {
    response.setCharacterEncoding("UTF-8");

    response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1
    response.setHeader("Pragma", "no-cache"); // HTTP 1.0

    /**
     * for ajax-cross-domain request TODO get the ip address from
     * configration(ajax-cross-domain.properties)
     */
    response.setHeader("Access-Control-Allow-Origin", "*");

    response.setDateHeader("Expires", 0); // Proxies.

    PrintWriter writer = getWriter(response);

    writeAjaxJSONResponse(responseObj, writer);
  }
 /**
   *
   * @param response
   * @return
   */
  protected PrintWriter getWriter(HttpServletResponse response) {
    if(null == response){
      return null;
    }

    PrintWriter writer = null;

    try {
      writer = response.getWriter();
    } catch (IOException e) {
      logger.error("unknow exception", e);
    }

    return writer;
  }

  /**
   * description:send the ajax response back to the client side.
   *
   * @param responseObj
   * @param writer
   * @param writer
   */
  protected void writeAjaxJSONResponse(Object responseObj, PrintWriter writer) {
    if (writer == null || responseObj == null) {
      return;
    }
    try {     writer.write(JSON.toJSONString(responseObj,SerializerFeature.DisableCircularReferenceDetect));
    } finally {
      writer.flush();
      writer.close();
    }
  }
}
接下来就是我们自己业务的 controller 了，其中主要是要调用 writeAjaxJSONResponse(result, response); 这个方法
@Controller
@RequestMapping(value = "/account")
public class AccountController extends BaseController {
@RequestMapping(value = "/add", method = RequestMethod.POST)
  public void addAccount(HttpSession session,HttpServletRequest request,HttpServletResponse response){
    ViewerResult result = new ViewerResult();
     //实现自己业务逻辑代码
    writeAjaxJSONResponse(result, response);
  }

}
好了，这种简单的方式就实现了。

import java.io.IOException;

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.http.HttpServletResponse;

public class HeadersCORSFilter implements Filter {

  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
    // TODO Auto-generated method stub

  }

  @Override
  public void doFilter(ServletRequest request, ServletResponse servletResponse,
      FilterChain chain) throws IOException, ServletException {
     HttpServletResponse response = (HttpServletResponse) servletResponse;
      response.setHeader("Access-Control-Allow-Origin", "*");
      response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
      response.setHeader("Access-Control-Max-Age", "3600");
      response.setHeader("Access-Control-Allow-Headers", "x-requested-with,Authorization");
      response.setHeader("Access-Control-Allow-Credentials","true");
      chain.doFilter(request, servletResponse);

  }

  @Override
  public void destroy() {
    // TODO Auto-generated method stub

  }

}
好了，filter 实现了，然后就是要在 web.xml 里面把这个 filter 运用起来了。
打开项目的 web.xml，填写下面的几行代码：

cors
   xxx.xxxx.xxxxx.xxxx.HeadersCORSFilter
  
   cors
   /open/*
  
好了，通过上面的3种方式，可以解决百分之80的跨域问题，也许还有更好的解决方案，可以提出来大家一起学习学习。
最好的方案是最符合当前需求且易于扩展的。