java前后端分离跨域解决方案

1.由于浏览器的同源策略，前后端分离的时候会出现跨域的问题。
java 的解决方案是：
手写一个corsFilter 实现 Filter . 然后在 doFilter 方法中定义：
笔者用的springboot ，其他架构可能配置方式有所不同

@Component
@ServletComponentScan
@WebFilter(urlPatterns = "/*",filterName = "CorsFilter")
public class CorsFilter implements Filter {private static Logger log = Logger.getLogger(CorsFilter.class);@Value("${curvar}")private String curvar;@Overridepublic void init(FilterConfig filterConfig) throws ServletException {www.sychzs.cn("添加自定义注解 {}" +curvar);System.out.print("添加自定义注解" + curvar);}@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)throws IOException, ServletException {HttpServletResponse response = (HttpServletResponse) servletResponse;//跨域response.setHeader("Access-Control-Allow-Origin", "*");//跨域 Headerresponse.setHeader("Access-Control-Allow-Methods", "*");response.setHeader("Access-Control-Allow-Headers", "Content-Type,XFILENAME,XFILECATEGORY,XFILESIZE");filterChain.doFilter(servletRequest, servletResponse);}@Overridepublic void destroy() {}}

前端的调用不受影响：

--------------------------------------- JS代码开始-------------------------------------------------------------------$("#btnButton").click(function () {var userName=$('#userName').val();  var password=$('#password').val();  var age=$('#age').val();  var email=$('#email').val();  var userbean={userName:userName,password:password,age:age,email:email};console.log(userbean);	//Ajax调用处理$.ajax({  type: "POST",  contentType : "application/json ; charset=utf-8",  url:"http://127.0.0.1:8080/user/addUser",  data:JSON.stringify(userbean),  dataType: "json",  async: false,  success:function(data){  alert("..");  }  });  
});--------------------------------------- JS代码结束-------------------------------------------------------------------

唯一要注意的是 data需要 转成 json

data:JSON.stringify(userbean);