前段ajax

<script type="text/javascript">

    function requestJson() {
        $.ajax({
        type : "post",
        url : "checkJosn",
        dataType:"json",
        success : function(msg) {
            alert(msg);
        }
        });
    }
</script

後端Controller

@Controller
 
public class JsonController {

    @ResponseBody
    @RequestMapping(value = "/checkJosn")
    public Student checkJosn(){
        Student student = new Student();
        student.setId(12);
        student.setUsername("chen");
        Address address = new Address();
        address.setCity(
 
"wuhan");
        student.setAddress(address);
        System.out.println("進入");
        return student;
    }

}

提交後，提示object，而註意到瀏覽器響應裏已經得到了json字符串，為啥alert不出來

百度了好久，使用 alert(JSON.stringify(msg));方法可以彈出json字符串。JSON.stringify()方法是將一個JavaScript值(對象或者數組)轉換為一個 JSON字符串

修改後ajax代碼

<script type="text/javascript">

    function
 
 requestJson() {
        $.ajax({
        type : "post",
        url : "checkJosn",
        dataType:"json",
        success : function(msg) {
            alert(JSON.stringify(msg));
        }
        });
    }
</script>

結果：

ajax得到後端數據一直提示為[object Object]解決方法