org.springframework.http.converter.HttpMessageNotReadableException

Question

public static List<UserAccountDetails> getUserAccountDetails() {
        List<UserAccountDetails> detailsList = new ArrayList<>();
        List<GrantedAuthority> authorities = getAuthorityList();

        UserAccountDetails accountDetail = UserAccountDetails.builder()
                                                             .firstName("People")
                                                             .lastName("Person")
                                                             .username("pperson")
                                                             .password("who")
                                                             .authorityList(authorities)
                                                             .build();
        detailsList.add(getUserDetails());
        detailsList.add(accountDetail);
        return detailsList;
    }

    private static List<GrantedAuthority> getAuthorityList() {
        List<GrantedAuthority> authorities = new ArrayList<>();
        authorities.add(new SimpleGrantedAuthority("ROLE_ADMIN"));
        authorities.add(new SimpleGrantedAuthority("ROLE_USER"));
        return authorities;
    }

我已經在下面的測試中設置了我的示例對象。

@Test
    public void checkCreateUsers() throws Exception{
        List<UserAccountDetails> detailsList = getUserAccountDetails();

        String jsonObject = mapper.writeValueAsString(detailsList);

        System.out.println(jsonObject);

        mockMvc.perform(post("/users/addUsers")
                .contentType(MediaType.APPLICATION_JSON)
                .content(jsonObject))
               .andDo(print())
               .andExpect(status().isCreated());
    }

我的測試失敗，因為ObjectMapper拋出以下錯誤。 我可以看到示例數據已正確序列化，然后嘗試使用mapper.registerSubtypes()進行嘗試，但也許我的實現是錯誤的。 任何幫助將不勝感激。 謝謝！！！

WARN 15972 --- [           main] .w.s.m.s.DefaultHandlerExceptionResolver : Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON document: Can not construct instance of org.springframework.security.core.GrantedAuthority: abstract types either need to be mapped to concrete types, have custom deserializer, or contain additional type information
 at [Source: java.io.PushbackInputStream@6242ae3b; line: 1, column: 115] (through reference chain: java.util.ArrayList[0]->com.sammy.domain.UserAccountDetails["authorityList"]->java.util.ArrayList[0]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of org.springframework.security.core.GrantedAuthority: abstract types either need to be mapped to concrete types, have custom deserializer, or contain additional type information
 at [Source: java.io.PushbackInputStream@6242ae3b; line: 1, column: 115] (through reference chain: java.util.ArrayList[0]->com.sammy.domain.UserAccountDetails["authorityList"]->java.util.ArrayList[0])

我根據@tsolakp給我的答案得到了這個新錯誤

2017-06-01 11:42:12.940  WARN 28663 --- [           main] .w.s.m.s.DefaultHandlerExceptionResolver : Failed to read HTTP message: org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON document: Can not construct instance of org.springframework.security.core.authority.SimpleGrantedAuthority: no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?)
 at [Source: java.io.PushbackInputStream@46a488c2; line: 1, column: 116] (through reference chain: java.util.ArrayList[0]->com.sammy.domain.UserAccountDetails["authorityList"]->java.util.ArrayList[0]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of org.springframework.security.core.authority.SimpleGrantedAuthority: no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?)
 at [Source: java.io.PushbackInputStream@46a488c2; line: 1, column: 116] (through reference chain: java.util.ArrayList[0]->com.sammy.domain.UserAccountDetails["authorityList"]->java.util.ArrayList[0])

Answer 1

非常明顯的例外是， GrantedAuthority不是具體的類（它是一個接口），並且映射器僅適用於具體的類，或者應該為GrantedAuthority使用自定義的序列化器/反序列化器。 一種解決方案是讓UserAccountDetails使用SimpleGrantedAuthority而不是GrantedAuthority 。