java后端解决跨域问题

1。允许整个项目跨域访问，可通过filter来进行过虑：

public class SimpleCORSFilter implements Filter{  
  
    @Override  
    public void destroy() {  
          
    }  
  
    @Override  
    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");  
            response.setHeader("Access-Control-Max-Age", "3600");  
            response.setHeader("Access-Control-Allow-Headers", "x-requested-with");  
            chain.doFilter(req, res);  
          
    }  
  
    @Override  
    public void init(FilterConfig arg0) throws ServletException {  
          
    }  
  
}
           

在web.xml中需要添加如下配置：

<filter>  
      <filter-name>cors</filter-name>  
      <filter-class>com.ssm.web.filter.SimpleCORSFilter</filter-class>  
    </filter>  
    <filter-mapping>  
      <filter-name>cors</filter-name>  
      <url-pattern>/*</url-pattern>  
    </filter-mapping>
</filter>
           

2。为单个方法提供跨域访问，直接添加请求头：

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");