web层返回结果参数封装

1.定义一个枚举类，如下所示：

public enum ResultEnum {
    SUCCESS(0,"成功"),
    ERROR(1,"失败"),
    FAIL(-1,"未知错误");

    private int code;
    private String msg;

    ResultEnum(int code, String msg) {
        this.code = code;
        this.msg = msg;
    }

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }
}

2.定义返回结果参数类，如下所示

public class ResponseParam implements Serializable {

    /**
     * 返回数据
     */
    private Map data = new HashMap<>();

    private int code;

    private String msg;

    public static ResponseParam SUCCESS(){
       return new ResponseParam(ResultEnum.SUCCESS);
    }

    public static ResponseParam ERROR(){
        return new ResponseParam(ResultEnum.ERROR);
    }

    public static ResponseParam FAIL(){
        return new ResponseParam(ResultEnum.FAIL);
    }

    private ResponseParam() {
    }

    private ResponseParam(ResultEnum resultEnum) {
       this.code = resultEnum.getCode();
       this.msg = resultEnum.getMsg();
    }

    private ResponseParam(int code, String msg,Map data) {
        this.data = data;
        this.code = code;
        this.msg = msg;
    }

    public static ResponseParam build(int code, String msg,Map data){
        return ResponseParam.ResponseParamBuilderHandler.build(code,msg,data);
    }

    public  ResponseParam addData(String key, T t){
        data.put(key,t);
        return this;
    }

    /**
     * 采用静态内部类实现单例模式创建对象
     */

    private static class ResponseParamBuilderHandler{
      private  static ResponseParam