![image](https://user-images.githubusercontent.com/54169514/199922630-ba1b1417-e124-40b1-bac7-49158e2adbca.png)

文档上ApplicationConfig的enableFileCache属性默认true，但是在Dubbo3.1版本中，该属性似乎默认为null，导致mapping和元数据无法在本地缓存。

![image](https://user-images.githubusercontent.com/54169514/199923129-c99ea29b-45c5-40d1-bc21-1fbb44830fc7.png)

Map<String, String> parameters1 = application1.getParameters();
        Assertions.assertEquals("value2", parameters1.get("tag2"));
        Assertions.assertEquals("value3", parameters1.get("tag3"));
        Map<String, String> urlParameters = new HashMap<>();
        ApplicationConfig.appendParameters(urlParameters, application1);
        Assertions.assertEquals("value1", urlParameters.get("tag1"));
        Assertions.assertEquals("value2", urlParameters.get("tag2"));
        Assertions.assertEquals("value3", urlParameters.get("tag3"));
    }
    @Test
    void testMetaData() {
        ApplicationConfig config = new ApplicationConfig();
        Map<String, String> metaData = config.getMetaData();
        Assertions.assertEquals(0, metaData.size(), "Expect empty metadata but found: "+metaData);
    }
    @Test
    void testOverrideEmptyConfig() {
        String owner = "tom1";
        SysProps.setProperty("dubbo.application.name", "demo-app");
        SysProps.setProperty("dubbo.application.owner", owner);
        SysProps.setProperty("dubbo.application.version", "1.2.3");
        ApplicationConfig applicationConfig = new ApplicationConfig();
        DubboBootstrap.getInstance()
            .application(applicationConfig)
            .initialize();
        Assertions.assertEquals(owner, applicationConfig.getOwner());
        Assertions.assertEquals("1.2.3", applicationConfig.getVersion());
        DubboBootstrap.getInstance().destroy();
    }
    @Test