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;
    }

我已经在上面设置了我的示例对象和下面的测试。

@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());
    }

我的测试失败了，因为ObjectMapper抛出了下面的错误。我可以看到示例数据是正确序列化的，然后尝试使用mapper.registerSubtypes()，但可能我的实现是错误的。任何帮助都将不胜感激。谢谢！

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])

根据@tsolakp给出的答案，我得到了这个新的错误

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

例外非常清楚地表明，GrantedAuthority不是一个具体的类(它是一个接口)，而且映射程序只能使用具体的类，或者应该有一个针对GrantedAuthority的自定义序列化程序/反序列化器。一种解决方案是让UserAccountDetails使用SimpleGrantedAuthority而不是GrantedAuthority。