json格式解析报错

Question

var carinfo ={
emptyseats : emptyseats,
carnum : carnum,
carbrand : carbrand,
driverage : driverage,
cardesc : cardesc,
isdown: isdown,
issmoking : issmoking,
iseating: iseating,
userid: userid
}; var URL = "savecarinfo.do"; $.ajax({
type : "post",// 使用post方法访问后台
dataType : "json",// 返回json格式的数据
url : URL,// 要访问的后台地址
async : "false",// 采用同步方式，必须先进行数据拉取后显示界面
contentType : "application/json;charset=utf-8",
data : {
carInfo:carinfo
}// 要发送的数据
});
后台解析总是报net.sf.json.JSONException: A JSONObject text must begin with '{' at character 1 of carInfo[emptyseats]=1&carInfo[carnum]=&carInfo[carbrand]=&carInfo[driverage]=&carInfo[cardesc]=&carInfo[isdown]=0&carInfo[issmoking]=1&carInfo[iseating]=0&carInfo[userid]=s24f566
at net.sf.json.util.JSONTokener.syntaxError(JSONTokener.java:512)
at net.sf.json.JSONObject._fromJSONTokener(JSONObject.java:1096)
at net.sf.json.JSONObject._fromString(JSONObject.java:1317)
at net.sf.json.JSONObject.fromObject(JSONObject.java:185)
at net.sf.json.JSONObject.fromObject(JSONObject.java:154)
at com.carpooling.controller.CarinfoController.saveCarinfo(CarinfoController.java:57)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:426)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:414)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1001)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:585)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
求修改方法！！！

Answer 1

 A JSONObject text must begin with '{

Answer 2

json 格式不对
参照:
http://www.cnblogs.com/webhotel/archive/2010/05/21/json.html

Answer 3

data: {carInfo: JSON.stringify(carInfo) },

Answer 4

还是不行啊，我打印出来的json怎么是
carInfo=%7B%22emptyseats%22%3A%221%22%2C%22carnum%22%3A%22%22%2C%22carbrand%22%3A%22%22%2C%22driverage%22%3A%22%22%2C%22cardesc%22%3A%22%22%2C%22isdown%22%3A0%2C%22issmoking%22%3A1%2C%22iseating%22%3A0%2C%22userid%22%3A%22s24f566%22%7D