ajax请求当发送post方式application/json格式数据，url后面又带有参数的时候

var url="${pageContext.request.contextPath}/json/jsonTest.do?idl=123&id=111";

$.ajax( {type : "POST",
url : url,
contentType:"application/json",
dataType: "JSON",
async : false, 
data : JSON.stringify({"name":"whj","age":"18","sex":"nv"}),
//data : {"id":"1","name":"whj","age":"18","sex":"nv"},
beforeSend: function(){

},
complete: function(){

},
success : function(data){//格式{key:value}
alert(data);
alert(data[0].name);
},
error: function(data) {
alert("error"); 
}
});

后台接受方法

@RequestMapping(value="jsonTest")
public @ResponseBody Person execute8(  Person person,String idl，Stirng id){
//public @ResponseBody List<Person> findAll(){
//模拟数据库方法
Logger.getLogger(JsonAction.class).debug("进入personFindAllaction");
后台控制台输出可以看到

person.toString=[id":"1","name":"whj","age":"18","sex":"nv"].

idl=123

id=111

return new Person(2,"whj1",25,"nan",new Date());

}

这里不会报错。

但是当去掉contentType:"application/json",

$.ajax( {type : "POST",

url : url,
//contentType:"application/json",
dataType: "JSON",
async : false, 
data : {"name":"whj","age":"18","sex":"nv"},
//data : {"id":"1","name":"whj","age":"18","sex":"nv"},
beforeSend: function(){

},
complete: function(){

},
success : function(data){//格式{key:value}
alert(data);
alert(data[0].name)


},
error: function(data) {
alert("error"); 
}
});

后台会报错。因为person id是int类型的 这时候其实送给后台id是111,1，格式转换时就会报错，具体为什么送json时不会报错，我估计是json直接把下面作为一个对象注入到person里面，其他id均在外面用其他实体接收

原文：https://blog.csdn.net/weixin_40648117/article/details/78667540