反射排序

反射排序

public <T> List<T> sortObject(List<T> list, Class<T> entityClass, String field) throws NoSuchMethodException,SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
        boolean isAllNumber = true;
        String methodName = "get" + field.substring(0, 1).toUpperCase() + field.substring(1);
        Method method = entityClass.getMethod(methodName, null);
        List<String> strList = new ArrayList<>();
        if (list == null)
            return null;
        for (T t : list) {
            strList.add((String) method.invoke(t, null));
        }
        for (String str : strList) {
            if (!str.matches("^\\d+$")) {
                isAllNumber = false;
            }
        }
        if (isAllNumber) {
            list.sort((Comparator<? super T>) new Comparator<T>() {
                @Override
                public int compare(T t1, T t2) {
                    try {
                        String o1 = (String) method.invoke(t1, null);
                        String o2 = (String) method.invoke(t2, null);
                        return Double.valueOf(o1).compareTo(Double.valueOf(o2));
                    } catch (Exception e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    return 0;
                }
            });
        } else {
            list.sort((Comparator<? super T>) new Comparator<T>() {

                @Override
                public int compare(T t1, T t2) {
                    try {
                        String o1 = (String) method.invoke(t1, null);
                        String o2 = (String) method.invoke(t2, null);
                        return o1.compareTo(o2);
                    } catch (Exception e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    return 0;
                }
            });
        }
        return null;

    }

---

来源于当时要对几种类似的列表进行同样的排序——如果此字段全是数字，按照数字排序；否则都按字符串排序。当然还有许多要改进的地方，比如entityClass可以在此段代码获取，没有传order direction等。