### Environment

* Dubbo version: 2.7.4.1
* Operating System version: macOS Catalina Version 10.15.3
* Java version: 1.8.0_231

### Steps to reproduce this issue

1. 通过telnet调用接口如下
方法(Method)
`public String convert7(UserInfoCondition userInfoCondition) {  }`
参数(Parameter)
`public class UserInfoCondition {
    private List<Map<Integer, UserInfo>> userList;
}`
`public class UserInfo {
    private String accountMobile;
    private String userPassword;
}`

invoke UsesrInfoFacade.convert7({"userList":[{"1":{"accountMobile":"15052234567"}}]})
or
invoke UsesrInfoFacade.convert7({"userList":[{1:{"accountMobile":"15052234567"}}]})

提示如下错误(has a problem)
![image](https://user-images.githubusercontent.com/17045745/77892951-ebd50d00-72a5-11ea-95b0-dd59a68a83cc.png)

到底如何书写这个入参呢?(How to write the parameters)


assertObject(new long[]{37L, -39L, 123456789L});
        assertObject(new Long[]{37L, -39L, 123456789L});
        assertObject(new float[]{37F, -3.14F, 123456.7F});
        assertObject(new Float[]{37F, -39F, 123456.7F});
        assertObject(new double[]{37D, -3.14D, 123456.7D});
        assertObject(new Double[]{37D, -39D, 123456.7D});
        assertArrayObject(new Boolean[]{true, false, true});
        assertArrayObject(new Byte[]{1, 12, 28, 78});
        assertArrayObject(new Character[]{'a', '中', '无'});
        assertArrayObject(new Short[]{37, 39, 12});
        assertArrayObject(new Integer[]{37, -39, 12456});
        assertArrayObject(new Long[]{37L, -39L, 123456789L});
        assertArrayObject(new Float[]{37F, -39F, 123456.7F});
        assertArrayObject(new Double[]{37D, -39D, 123456.7D});
    }
    @Test
    public void test_PojoArray() throws Exception {
        Person[] array = new Person[2];
        array[0] = new Person();
        {
            Person person = new Person();
            person.setName("xxxx");
            array[1] = person;
        }
        assertArrayObject(array);
    }
    @Test
    public void testArrayToCollection() throws Exception {
        Person[] array = new Person[2];
        Person person1 = new Person();