ajax请求，跨域问题，在Java客户端中解决

在controller中添加如下代码，这种办法，时灵时不灵，可以尝试下：

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");
或：
response.addHeader("Access-Control-Allow-Origin", "*");
response.addHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE");
response.addHeader("Access-Control-Allow-Headers", "Content-Type");

另外一种方法是在配置文件中统一配置，这样似乎更有效，而且不用在每个controller中的方法中都重复写，更方便。

来自博客http://m.blog.csdn.net/article/details?id=51418384

在项目任意路径下新建一个类CORSFilter.java

public class CORSFilter implements Filter {
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.addHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
chain.doFilter(req, res);
}
public void init(FilterConfig filterConfig) {}
public void destroy() {}
}

在web.xml文件中添加如下代码：

<filter>
<filter-name>cors</filter-name>
<filter-class>xxxx.CORSFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>cors</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>