R 返回数据类型

import java.util.HashMap;
import java.util.Map;

/**
 * 返回数据
 */
public class R extends HashMap<String, Object> {
   private static final long serialVersionUID = 1L;
   
   public R() {
      put("code", 0);
   }
   
   public static R error() {
      return error(500, "未知异常，请联系管理员");
   }
   
   public static R error(String msg) {
      return error(500, msg);
   }
   
   public static R error(int code, String msg) {
      R r = new R();
      r.put("code", code);
      r.put("msg", msg);
      return r;
   }

   public static R ok(String msg) {
      R r = new R();
      r.put("msg", msg);
      return r;
   }
   
   public static R ok(Map<String, Object> map) {
      R r = new R();
      r.putAll(map);
      return r;
   }
   
   public static R ok() {
      return new R();
   }

   public R put(String key, Object value) {
      super.put(key, value);
      return this;
   }
}