SSM框架中封装后端返回的Json数据

①首先需要一个封装类（泛型类）

/**

* 封装后端返回的Json数据

*/

//保证序列化json时，如果是null的对象，key也会消失

@JsonInclude(JsonInclude.Include.NON_NULL)

public class ServerResponse<T> {

//状态码

private int statu;

//数据

private T data;

//描述信息

private String msg;

//setter、getter方法

public int getStatu() {

return statu;

}

public void setStatu(int statu) {

this.statu = statu;

}

public T getData() {

return data;

}

public void setData(T data) {

this.data = data;

}

public String getMsg() {

return msg;

}

public void setMsg(String msg) {

this.msg = msg;

}

//构造函数

/**

* 操作成功时，返回数据

* @param statu

* @param data

* @param msg

*/

public ServerResponse(int statu, T data, String msg) {

this.statu = statu;

this.data = data;

this.msg = msg;

}

public ServerResponse(int statu) {

this.statu = statu;

}

/**

* 操作失败时，不返回数据

* @param statu

* @param msg

*/

public ServerResponse(int statu, String msg) {

this.statu = statu;

this.msg = msg;

}

//使之不在序列化结果中

@JsonIgnore

public boolean checkIsSuccess(){

return this.statu==ResponseCode.SUCCESS.getCode();

}

//泛型方法

/**

* 成功返回数据

* @param msg

* @param data

* @param

* @return

*/

public static <T> ServerResponse<T> createBySuccess(String msg,T data){

return new ServerResponse<T>(ResponseCode.SUCCESS.getCode(),data,msg);

}

/**

* 用于校验登录信息

* @param

* @return

*/

public static <T> ServerResponse<T> createByCheckSuccess(){

return new ServerResponse<T>(ResponseCode.SUCCESS.getCode());

}

/**

* 返回错误信息

* @param msg

* @param

* @return

*/

public static <T> ServerResponse<T> createByError(String msg){

return new ServerResponse<T>(ResponseCode.ERROR.getCode(),msg);

}

public static <T> ServerResponse<T> createByNeedLogin(){

return new ServerResponse<T>(ResponseCode.NEED_LOG.getCode(),"请先登录！");

}

}

②将常量写成一个枚举类

/**

* 定义响应的状态码

*/

public enum ResponseCode {

SUCCESS(100,"SUCCESS"),

ERROR(101,"ERROR"),

NEED_LOG(1,"NEED_LOG");

private int code;

private String desc;

public int getCode() {

return code;

}

public void setCode(int code) {

this.code = code;

}

public String getDesc() {

return desc;

}

public void setDesc(String desc) {

this.desc = desc;

}

ResponseCode(int code, String desc) {

this.code = code;

this.desc = desc;

}

}

③当有数据返回时，service层，controller层返回的数据类型为以上这个封装类

   以显示所有学生信息为例,service层：

/**

* 这时可以指定具体的封装类的泛型类型

* @return

*/

@Override

public ServerResponse> showAllStudent() {

//DAO层查询数据

List studentList = studentDao.showAllStudent();

if (studentList.size()>0){

return ServerResponse.createBySuccess("查询成功",studentDao.showAllStudent());

}

return ServerResponse.createByError("查询记录为空");

}

controller层：

@RequestMapping(value = "/showStudents")

@ResponseBody

public ServerResponse showAllStudent(HttpSession session){

//登录校验

ServerResponse serverResponse = CheckRole.checkIsLoginAndAdmin(session);

//校验成功

if (serverResponse.checkIsSuccess()){

return studentService.showAllStudent();

}

return serverResponse;

}

登录校验：参考我的博客：SSM框架中基于session的登录校验

测试：