Question

我在读取.JSON文件和创建DTO对象时遇到了麻烦……当我只读时，我从json文件中获得了第一项，其他所有内容都为null。为什么会发生？我的变量在类中的写入方式应与json中的相同？

Dto类

public class AlunoTestDto {

private String table;
private String rows;
private String AlunoID;
private String Nome;
private String RM;
private String RG;
private String usuario;
private String senha;
private String cursoAluno;
private String urlFoto;
private String email;
private String rgEscolar;
private String cpf;


public String getTable() {
    return table;
}

public void setTable(String table) {
    this.table = table;
}

public String getRow() {
    return rows;
}

public void setRow(String rows) {
    this.rows = rows;
}//others

读取json的方法

 ObjectMapper objectMapper = new ObjectMapper();
    objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    AlunoTestDto alunoTestDto=null;
    alunoTestDto = objectMapper.readValue(new File("alunos2.json"), AlunoTestDto.class);

Json文件

        "table": "bws_aluno",
"rows":
[
    {
        "AlunoID": 1,
        "Nome": "Mayk Reserv",
        "RM": "4545454545",
        "RG": "7535214-7",
        "Usuario": null,
        "Senha": null,
        "CursoAluno": null,
        "UrlFoto": null,
        "Email": "",
        "RGEscolar": null,
        "CPF": null     
    },
    {
        "AlunoID": 2,
        "Nome": "Philip Lombard",
        "RM": "26585651",
        "RG": "123456980",
        "Usuario": null,
        "Senha": null,
        "CursoAluno": null,
        "UrlFoto": null,
        "Email": "",
        "RGEscolar": null,
        "CPF": null

    },
    {
        "AlunoID": 3,
        "Nome": "Bilbo Bolseiro",
        "RM": "75898774",
        "RG": "36522-8",
        "Usuario": null,
        "Senha": null,
        "CursoAluno": null,
        "UrlFoto": null,
        "Email": "",
        "RGEscolar": null,
        "CPF": null         
    }
]

}

null object image

Answer 1

JSON中的

"rows":是数组或对象列表（比如说class Row），但是您的DTO使用row作为字符串...

因此，JSON文件中没有任何内容可以填充"table"元素

仅读取json文件中的第一项

1 个答案: