json格式的Ajax提交示例代码

<form class="form-inline"> 
扫码: <input id="txtqrcode" type="text"> 
<button id="btnreceive">确定</button> 
</form> 

<script type="text/javascript"> 
//扫描二维码 
$('#btnreceive').click(function(){ 
$.ajax({ 
type:"get", 
url:"<%=basepath%>asynchronous/receive.do", 
data:{qrcode:$('#txtqrcode').val()}, 
datatype:"json", 
cache:false, 
success:function(msg){ 
//var json = eval('('+msg+')');//拼接的json串 

var flag = msg.flag; 
var info = msg.info; 
if(flag){ 
alert(info); 
$('#txtqrcode').val(""); 
} 
else{ 
alert(info); 
} 
}, 
error:function(error){alert(error);} 
}); 
}); 
}); 
</script> 

package com.utcsoft.pcapps.selfservice.controller; 
import java.io.ioexception; 
import java.io.printwriter; 
import java.net.unknownhostexception; 
import javax.servlet.http.httpservletrequest; 
import javax.servlet.http.httpservletresponse; 
import org.apache.commons.logging.log; 
import org.apache.commons.logging.logfactory; 
import org.json.jsonexception; 
import org.json.jsonobject; 
import org.springframework.stereotype.controller; 
import org.springframework.web.bind.annotation.requestmapping; 

import com.utcsoft.common.attributes.yesnoenum; 
import com.utcsoft.common.util.dateoperate; 
import com.utcsoft.pcapps.selfservice.attributes.keyrequestattr; 
import com.utcsoft.pcapps.selfservice.dao.flowdao; 
import com.utcsoft.pcapps.selfservice.dao.keyrequestdao; 
import com.utcsoft.pcapps.selfservice.entity.flow; 
import com.utcsoft.pcapps.selfservice.entity.keyrequest; 
import com.utcsoft.pcapps.selfservice.entity.utcusers; 

@controller 
@requestmapping(value = "/asynchronous") 
public class asynchronouscontroller { 
private final static log logger = logfactory.getlog(asynchronouscontroller.class); 

/** 
* 扫描二维码 将订单改为utc审核 
* @param request 
* @param response 
* @throws ioexception 
* @throws jsonexception 
*/ 
@requestmapping(value="/receive") 
public void receive(httpservletrequest request,httpservletresponse response) throws ioexception, jsonexception{ 
string rets = ""; 
boolean b = false; 
try{ 
string qrcode = request.getparameter("qrcode")==null?"":request.getparameter("qrcode").tostring().trim(); 
logger.info(qrcode); 
if(!"".equals(qrcode)){ 
jsonobject obj = new jsonobject(qrcode); 
string orderid = obj.getstring("orderid").trim(); 
if(!"".equals(orderid)){ 
keyrequestdao keydao = new keyrequestdao(); 
keyrequest k = new keyrequest();//综合信息 
k = keydao.findonebyorderid(orderid); 
if(k!=null){ 
//修改订单状态为审核 
int n = keydao.updatestate(orderid, string.valueof(keyrequestattr.kqstateenum.verify.getstep())); 
flow flow = new flow(); 
flowdao flowdao = new flowdao(); 
utcusers users = (utcusers)request.getsession().getattribute("utcusers"); 
//将记录插入flwo表中 
flow.setkq_id(orderid); 
flow.setkq_state(string.valueof(keyrequestattr.kqstateenum.cus_send.getstep())); 
flow.setkq_state_to(string.valueof(keyrequestattr.kqstateenum.verify.getstep())); 
flow.setis_pass(yesnoenum.y.getcode()); 
flow.setuser_id(users.getuser_id()); 
flow.setuser_id_from(users.getuser_id()); 
flow.setoptimer(dateoperate.getdatetime()); 
int flownum = flowdao.save(flow); 
logger.info("扫描二维码提交结果：n="+n+";flownum="+flownum); 
if(n>0){ 
b = true; 
rets = "utc接收订单成功"; 
logger.info("utc接收订单成功"); 
} 
else{ 
rets = "utc接收订单失败"; 
logger.info("utc接收订单失败"); 
} 
} 
else{ 
rets = "订单查询失败"; 
logger.info("订单查询失败"); 
} 
} 
else{ 
rets = "二维码中订单号为空"; 
logger.error("二维码中订单号为空"); 
} 
} 
else{ 
rets = "二维码内容为空"; 
logger.error("二维码内容为空"); 
} 

} 
catch(exception e){ 
e.printstacktrace(); 
rets = e.getmessage(); 
logger.error(e.getmessage()); 
} 

jsonobject ret = new jsonobject(); 
ret.put("flag", b); 
ret.put("info", rets); 
printwriter write = response.getwriter(); 
write.write(ret.tostring()); 
write.flush(); 
} 
}