当我们使用arcgis api for javascript 查询arcgis服务时，如果查询的参数很长时，通过get方式提交会查询不到结果，因为get方式提交的参数有长度限制，需要通过代理的方式使用post提交。

arcgis 提供了一种解决方案就是proxy.jsp.

首先在项目页面js中引入 proxy.jsp：esriConfig.defaults.io.proxyUrl=http://servername:prot/arcgis_js_api/proxy.jsp  引入代理页面

esriConfig.defaults.io.alwaysUseProxy=true;         设置代理是否一直起作用

引入之后把proxy.jsp放入到项目中。

代理页面源码如下：

<%@page session="false"%>
<%@page import="java.net.*,java.io.*" %>
<%!
String[] serverUrls = {"http://servername:8399/arcgis/rest/services"//对什么服务起作用，可以配置多个用","分割。
};
try {String reqUrl = request.getQueryString();boolean allowed = false;String token = null;for(String surl : serverUrls) {String[] stokens = surl.split("\\s*,\\s*");if(reqUrl.toLowerCase().contains(stokens[0].toLowerCase())) {allowed = true;if(stokens.length >= 2 && stokens[1].length() > 0)token = stokens[1];break;}}if(reqUrl.endsWith(".png")) allowed = true;if(!allowed) {response.setStatus(403);return;}if(token != null) {reqUrl = reqUrl + (reqUrl.indexOf("?") > -1 ? "&" : "?") + "token=" + token;}URL url = new URL(reqUrl);HttpURLConnection con = (HttpURLConnection)url.openConnection();con.setDoOutput(true);con.setRequestMethod(request.getMethod());if(request.getContentType() != null) {con.setRequestProperty("Content-Type", request.getContentType());}con.setRequestProperty("Referer", request.getHeader("Referer"));int clength = request.getContentLength();if(clength > 0) {con.setDoInput(true);InputStream istream = request.getInputStream();OutputStream os = con.getOutputStream();final int length = 5000;byte[] bytes = new byte[length];int bytesRead = 0;while ((bytesRead = istream.read(bytes, 0, length)) > 0) {os.write(bytes, 0, bytesRead);}}else {con.setRequestMethod("GET");}out.clear();out = pageContext.pushBody();OutputStream ostream = response.getOutputStream();response.setContentType(con.getContentType());InputStream in = con.getInputStream();final int length = 5000;byte[] bytes = new byte[length];int bytesRead = 0;while ((bytesRead = in.read(bytes, 0, length)) > 0) {ostream.write(bytes, 0, bytesRead);}
} catch(Exception e) {response.setStatus(500);
}
%>