Circular view path [home]: would dispatch back to the current handler URL [/home] again. Check your ViewResolver setup! 
(Hint: This may be the result of an unspecified view, due to default view name generation.)

1. 問題的現象

比如在webConfig中定義了一個viewResolver

public class WebConfig extends WebMvcConfigurerAdapter {

    //配置JSP視圖解析器
    @Bean
    public ViewResolver viewResolver() {
        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
        resolver.setPrefix("WEB-INF/views/");
        resolver.setSuffix(".jsp");
        resolver.setExposeContextBeansAsAttributes(true);
        return resolver;
    }
 
}

然後定義了一個controller，URL路徑為"/home", 它返回名字叫home的view

@Controller
public class HomeController {
    @RequestMapping(value = "/home", method=GET)
    public ModelAndView home() {
        String message = "Hello";
        return new ModelAndView("home", "home", message);
    }
}

然後定義了個Test

public class HomeControllerTest {
    @Test
    public void testHomePage() throws Exception {
        HomeController controller = new HomeController();
        MockMvc mockMvc = standaloneSetup(controller).build();
        mockMvc.perform(get("/home")).andExpect(view().name("home"));
    }

}

那麽執行Test是就會報類似錯誤並拋出異常：

Circular view path [home]: would dispatch back to the current handler URL [/home] again. Check your ViewResolver setup! 
(Hint: This may be the result of an unspecified view, due to default view name generation.)

2. 首先，首先說下原因：

-------------------------------

當沒有聲明ViewResolver時，spring會給你註冊一個默認的ViewResolver，就是JstlView的實例， 該對象繼承自InternalResoureView。

JstlView用來封裝JSP或者同一Web應用中的其他資源，它將model對象作為request請求的屬性值暴露出來, 並將該請求通過javax.servlet.RequestDispatcher轉發到指定的URL.

Spring認為， 這個view的URL是可以用來指定同一web應用中特定資源的，是可以被RequestDispatcher轉發的。

也就是說，在頁面渲染(render)之前，Spring會試圖使用RequestDispatcher來繼續轉發該請求。如下代碼：

if (path.startsWith("/") ? uri.equals(path) : uri.equals(StringUtils.applyRelativePath(uri, path))) {
    throw new ServletException("Circular view path [" + path + "]: would dispatch back " +
                        "to the current handler URL [" + uri + "] again. Check your ViewResolver setup! " +
                        "(Hint: This may be the result of an unspecified view, due to default view name generation.)");
}

從這段代碼可以看出，如果你的view name和你的path是相同的字符串，根據Spring的轉發規則，就等於讓自己轉發給自己，會陷入死循環。所以Spring會檢查到這種情況，於是拋出Circular view path異常。

3. 其次，如何解決？

通過原因分析，造成問題有兩個因素：1). 缺省轉發， 2). view和path同名

那麽消除這兩個因素任何一個就可以解決這個問題。

3.1 解決辦法一： 消除缺省轉發

雖然在controller中已經定義了view, 但在使用Spring Test時卻仍然無效，這個不知道什麽原因，也許是Spring Test的Bug, 有待探究。既然無效，那就在Test中重新定義一下view

, 這樣雖然麻煩點，但畢竟消除了缺省轉發，所以可以解決問題。示例代碼如下：

public class TestJavaConfig {

    private MockMvc mockMvc;

    @InjectMocks
    private StudentController studentController;

    @Mock
    private StudentService studentService;

    @Before
    public void setUp(){
        MockitoAnnotations.initMocks(this);
        InternalResourceViewResolver resolver = new InternalResourceViewResolver(); //在test中重新配置視圖解析器
        resolver.setPrefix("/WEB_INF/views");
        resolver.setSuffix(".jsp");
        mockMvc = MockMvcBuilders.standaloneSetup(studentController).setViewResolvers(resolver).build();

    }
    @Test
    public void testList()throws Exception{
        mockMvc.perform(get("/home")).andExpect(view().name("home"));
    }

3.2 解決辦法二： 修改view和path，讓他們不同名

這個方法最簡單，建議用這種辦法，比如上面的home視圖， 只要我們的path不是"/home"就可以，可以改view名字（比如改成homepage），或者修改/path(比如/root).

https://www.cnblogs.com/chry/p/6240965.html

Circular view path [home]: would dispatch back to the current handler URL [/home] again. Check your ViewResolver setup!