反射

•  获取Class类

    //获取Class类
   //（方法一）
   Class class1 = UserBean.class;
   //（方法二）
  Class class2 = new UserBean().getClass();
   //（方法三）
   Class class3 = Class.forName("cn.xxx.domain.UserBean");

•  利用反射封装JavaBean数据

  /**
       * 封装JavaBean数据
       *
       * @param t
       * @param m
       * @param <T>
       * @throws IllegalAccessException
       * @throws InstantiationException
       */
      private <T> T getBean(T t, Map<String, String[]> m) throws IllegalAccessException, InstantiationException {
          //记录存储数据的属性名
          ArrayList<String> names = new ArrayList();
          //获取Class类
          Class c = (Class) t;
          //获取Class类的父类
          Class cParent = c.getSuperclass();
          //实例类
          T cParentIn = (T) c.newInstance();
          Set<Map.Entry<String, String[]>> entries = m.entrySet();
          Iterator<Map.Entry<String, String[]>> iterator = entries.iterator();
          //获取全部字段，包括私有字段
          Field[] declaredFields = cParent.getDeclaredFields();
          //
          while (iterator.hasNext()) {
              Map.Entry<String, String[]> next = iterator.next();
              String[] strs = next.getValue();
              for (Field field : declaredFields) {
                  if (next.getKey().equals(field.getName())) {
                      //设置私有对象可以访问
                      field.setAccessible(true);
                      String name = next.getKey();
                      String value = strs[0];
                      try {
                          //获取属性,name为参数名
                          Field declaredField = cParent.getDeclaredField(name);
                          //设置私有对象可以访问
                          declaredField.setAccessible(true);
                          //一定要子类实例，不然没有办法访问父类私有属性，cParentIn是类的实例
                          declaredField.set(cParentIn, value);
                          names.add(name);
                      } catch (NoSuchFieldException e) {
                          e.printStackTrace();
                      }
  
                      break;
                  }
              }
          }
  
          //获取类中参数的值
          //方法一：
          for (Field field : declaredFields) {
              field.setAccessible(true);
              String name = field.getName();
              try {
                  Field declaredField = cParent.getDeclaredField(name);
                  if (declaredField != null) {
                      declaredField.setAccessible(true);
                      //一定要判断，不然当属性值为空就会报错
                      if (declaredField.get(cParentIn) != null) {
                          //获取参数
                          String value = declaredField.get(cParentIn).toString();
                          System.out.println("key=" + name + ",value=" + value);
                      }
                  }
  
              } catch (NoSuchFieldException e) {
                  e.printStackTrace();
              }
          }
  
          //方法二
          try {
              for (String name : names) {
                  Field declaredField = cParent.getDeclaredField(name);
                  declaredField.setAccessible(true);
                  String value = declaredField.get(cParentIn).toString();
                  System.out.println("key=" + name + ",value=" + value);
              }
          } catch (NoSuchFieldException e) {
              e.printStackTrace();
          }
  
          return cParentIn;
      }