如何使用spring restdocs记录包含JSON对象的请求体

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.restdocs.AutoConfigureRestDocs;
import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.restdocs.mockmvc.MockMvcRestDocumentation;
import org.springframework.restdocs.mockmvc.RestDocumentationRequestBuilders;
import org.springframework.restdocs.payload.JsonFieldType;
import org.springframework.restdocs.payload.PayloadDocumentation;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.ResultActions;

import static org.springframework.restdocs.mockmvc.MockMvcRestDocumentation.document;
import static org.springframework.restdocs.mockmvc.MockMvcRestDocumentation.documentationConfiguration;
import static org.springframework.restdocs.payload.PayloadDocumentation.fieldWithPath;
import static org.springframework.restdocs.payload.PayloadDocumentation.requestFields;

@RunWith(SpringRunner.class)
@WebMvcTest
@AutoConfigureRestDocs(outputDir = "target/generated-snippets")
public class ApiDocumentation {

    @Autowired
    private MockMvc mockMvc;

    @Before
    public void setUp() {
        this.mockMvc = MockMvcBuilders
                .webAppContextSetup(context)
                .apply(documentationConfiguration(this.restDocumentation))
                .build();
    }

    @Test
    public void exampleTest() throws Exception {
        ResultActions result = this.mockMvc.perform(RestDocumentationRequestBuilders.post("/api/endpoint")
                .content("{\"name\": \"John\", \"age\": 30}")
                .contentType(MediaType.APPLICATION_JSON));

        result.andExpect(status().isOk())
                .andDo(document("example",
                        requestFields(
                                fieldWithPath("name").type(JsonFieldType.STRING).description("The name of the person"),
                                fieldWithPath("age").type(JsonFieldType.NUMBER).description("The age of the person")
                        )
                ));
    }
}