反射的一些用法

灰太狼 2022-05-15 10:42 314阅读 0赞

/**
         * 根据属性名获取属性值
         * @param fieldName
         * @param object
         * @param <T>
         * @return
         */
        public static <T> T  getFieldValueByFieldName(String fieldName, Object object) {
            try {
                Field field = object.getClass().getDeclaredField(fieldName);
                //设置对象的访问权限，保证对private的属性的访问
                field.setAccessible(true);
                return  (T)field.get(object);
            } catch (Exception e) {
                e.printStackTrace();
                return null;
            }
        }
    
        /**
         * sql语句中where都是=这种判断时，如id=#{bean.id} and createTime=#{bean.createTime},
         * 此时ES按这种条件查询，就可以使用该方法
         *
         * @param model
         * @param map
         */
        public static void setKeyValue(Object model, Map<String, String> map) {
            try{
                String get = "get";
                // 获取实体类的所有属性，返回Field数组
                Field[] field = FieldUtils.getAllFields(model.getClass());
                // 遍历所有属性
                for (Field aField : field) {
                    // 获取属性的名字
                    String key = aField.getName();
                    // 将属性的首字符大写，方便构造get，set方法
                    String name = key.substring(0, 1).toUpperCase() + key.substring(1);
                    // 获取属性的类型
                    String type = aField.getGenericType().toString();
                    // 如果type是类类型，则前面包含"class "，后面跟类名
                    if (StringUtils.equals(type, String.class.toString())) {
                        Method m = model.getClass().getMethod(get + name);
                        // 调用getter方法获取属性值
                        String value = (String) m.invoke(model);
                        if (StringUtils.isNotBlank(value)){
                            map.put(key, value);
                        }
                    }
                    if (StringUtils.equals(type, Integer.class.toString())) {
                        Method m = model.getClass().getMethod(get + name);
                        Integer value = (Integer) m.invoke(model);
                        if (null != value){
                            map.put(key, String.valueOf(value));
                        }
                    }
                    if (StringUtils.equals(type, Long.class.toString())) {
                        Method m = model.getClass().getMethod(get + name);
                        Long value = (Long) m.invoke(model);
                        if (null != value){
                            map.put(key, String.valueOf(value));
                        }
                    }
                    if (StringUtils.equals(type, Short.class.toString())) {
                        Method m = model.getClass().getMethod(get + name);
                        Short value = (Short) m.invoke(model);
                        if (null != value){
                            map.put(key, String.valueOf(value));
                        }
                    }
                    if (StringUtils.equals(type, Double.class.toString())) {
                        Method m = model.getClass().getMethod(get + name);
                        Double value = (Double) m.invoke(model);
                        if (null != value){
                            map.put(key, String.valueOf(value));
                        }
                    }
                    if (StringUtils.equals(type, Boolean.class.toString())) {
                        Method m = model.getClass().getMethod(get + name);
                        Boolean value = (Boolean) m.invoke(model);
                        if (null != value){
                            map.put(key, String.valueOf(value));
                        }
                    }
                    if (StringUtils.equals(type, Date.class.toString())) {
                        Method m = model.getClass().getMethod(get + name);
                        Date value = (Date) m.invoke(model);
                        if (null != value){
                            map.put(key, DateUtils.formatDate(value, DateUtils.yyyy_MM_dd_HH_mm_ss_SSS));
                        }
                    }
                    if (StringUtils.equals(type, BigDecimal.class.toString())) {
                        Method m = model.getClass().getMethod(get + name);
                        BigDecimal value = (BigDecimal) m.invoke(model);
                        if (null != value){
                            map.put(key, String.valueOf(value));
                        }
                    }
                }
            } catch (Throwable t){
                throw new RuntimeException(t);
            }
        }