Question

我使用的是jackson 2.6.x. 我无法将json转换为java类

public class ParentTest {
@JsonProperty("ParentTest")
public List<Test> getTestList() {
    return testList;
}

public void setTestList(List<Test> testList) {
    this.testList = testList;
}

@JsonProperty("ParentTest")
List<Test> testList;

public ParentTest(List<Test> testList)
{   
    this.testList = testList;
}

public ParentTest()
{
    super();
    testList = new ArrayList<Test>();
}

public String toString()
{
    String r = "";
    if(testList!=null)
    for(Test t : testList)
    {
        r += "Test:"+t.field1+t.field2; 
    }
    else
        r = "null";
    return r;
}}

用于列表的类是

@JsonRootName("Test")public class Test {
@JsonProperty("field1")
String field1;
@JsonProperty("field2")
String field2;
public Test(String field1,String field2)
{

    this.field1 = field1;

    this.field2 = field2;
}
public String getField1() {
    return field1;
}
public void setField1(String field1) {
    this.field1 = field1;
}
public String getField2() {
    return field2;
}
public void setField2(String field2) {
    this.field2 = field2;
}}

我的Json是

{"ParentTest":   [{
"Test":{
        "field1":"t1",
        "field2":"t2"
         }
},
{
"Test":{
        "field1":"t3",
        "field2":"t4"
         }
}]}

为了阅读它，我使用了

public final class HandlerJacksonUtils {
private static ObjectMapper m = new ObjectMapper();
private static JsonFactory jf = new JsonFactory();

    public static <T> Object fromJson(String jsonAsString, Class<T> pojoClass) throws IOException {
        m.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        return m.readValue(jsonAsString, pojoClass);
    }}

然后

ParentTest pt = (ParentTest) HandlerJacksonUtils.fromJson(json, ParentTest.class);

ParentTest对象pt在System.out.print（pt.toString）上不打印任何内容;

Answer 1

@JsonRootName不能单独工作，如javadocs中所述。您应该将其与SerializationFeature#WRAP_ROOT_VALUE和/或DeserializationFeature#UNWRAP_ROOT_VALUE结合使用。但它仅适用于您要序列化/反序列化的根对象。因此，它不适用于您的情况。相反，您可以为Test

创建一个包装类

public class TestWrapper {

    @JsonProperty("Test")
    private Test test;

    public Test getTest() {
        return test;
    }

    public void setTest(Test test) {
        this.test = test;
    }
}

在Test

中使用它代替ParentTest

杰克逊：Json将json数组放到java类中，列出了另一个Java类

1 个答案: