arcgis api for javascript中使用proxy.jsp

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);
}
%>