Question

我正在尝试使用fastxml将json回复解析为POJO。但是问题是json回复包含嵌套对象，其中包含反斜杠，因此在ObjectMapper读取此值期间，我正在接收com.fasterxml.jackson.databind.exc.MismatchedInputException

com.fasterxml.jackson.databind.exc.MismatchedInputException：无法构造com.am.api.Message的实例（尽管存在至少一个Creator）：没有用于从字符串值反序列化的字符串参数构造函数/工厂方法（'{ entryType“：”购买“，”汇率“：” 22000.0“，”操作“：”更新“，” offerId“：” b96f2da7-55f9-4221-aaa3-8e3ad177567d“，”市场“：” BTC-PLN“，”状态”：{“市场”：“ BTC-PLN”，“ offerType”：“购买”，“ id”：“ b96f2da7-55f9-4221-aaa3-8e3ad177567d”，“当前金额”：“ 0.0005”，“锁定金额”： “ 11.00”，“ rate”：“ 22000.0”，“ startAmount”：“ 0.0005”，“ time”：“ 1535023208260”，“ postOnly”：false，“ hidden”：false，“ mode”：“ limit”，“ receivedAmount “：” 0“}}'）在[来源：（字符串）” { “ topic”：“交易/报价/ BTC-PLN”， “ message”：“ {\” entryType \“：\” Buy \“，\” rate \“：\” 22000.0 \“，\” action \“：\” update \“，\” offerId \“：\” b96f2da7-55f9-4221-aaa3-8e3ad177567d \“，\”市场\“：\” BTC-PLN \“，\”状态\“：{\”市场\“：\” BTC-PLN \“，\” offerType \“：\”购买\“，\” id \“：\” b96f2da7-55f9-4221-aaa3-8e3ad177567d \“，\” currentAmount \“：\” 0.0005 \“，\” lockedAmount \“：\” 11.00 \“，\” rate \“：\” 22000.0 \“，\” startAmount \“：\” 0.0005 \“，\” time \“：\” 1535023208260 \“，\” postOnly \“：false，\”隐藏\“：false，\” mode \“：\” limit \“，\” receivedAmoun“ [截短45个字符]；第3行，第13列]（通过引用链：com.am.api.WsOrderReply [” message “]）在com.fasterxml.jackson.databind.exc.MismatchedInputException.from（MismatchedInputException.java:63）在com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch（DeserializationContext.java:1329）在com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator（DeserializationContext.java:1031）处在com.fasterxml.jackson.databind.deser.ValueInstantiator._createFromStringFallbacks（ValueInstantiator.java:370）在com.fasterxml.jackson.databind.deser.std.StdValueInstantiator.createFromString（StdValueInstantiator.java:314）在com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromString（BeanDeserializerBase.java:1351）在com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeOther（BeanDeserializer.java:170）在com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize（BeanDeserializer.java:161）在com.fasterxml.jackson.databind.deser.SettableBeanProperty.deserialize（SettableBeanProperty.java:519）在com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeWithErrorWrapping（BeanDeserializer.java:527）在com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeUsingPropertyBased（BeanDeserializer.java:416）在com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault（BeanDeserializerBase.java:1265）在com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject（BeanDeserializer.java:325）在com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize（BeanDeserializer.java:159）在com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose（ObjectMapper.java:4001）在com.fasterxml.jackson.databind.ObjectMapper.readValue（ObjectMapper.java:2992）在com.am.ReplyMapper.readValue（ReplyMapper.java:154）在com.am.ReplyMapper.mapReplyToCommonExecutionReport（ReplyMapper.java:73）在com.am.ReplyMapper.lambda $ apply $ 1（ReplyMapper.java:54）在java.util.Optional.map（Optional.java:215）在com.am.ReplyMapper.apply（ReplyMapper.java:54）在com.am.ReplyMapperTest.shouldMapUpdateOrderReplyNew（ReplyMapperTest.java:64）在sun.reflect.NativeMethodAccessorImpl.invoke0（本机方法）处在sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:62）在sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）在java.lang.reflect.Method.invoke（Method.java:498）在org.junit.runners.model.FrameworkMethod $ 1.runReflectiveCall（FrameworkMethod.java:50）在org.junit.internal.runners.model.ReflectiveCallable.run（ReflectiveCallable.java:12）在org.junit.runners.model.FrameworkMethod.invokeExplosively（FrameworkMethod.java:47）在org.junit.internal.runners.statements.InvokeMethod.evaluate（InvokeMethod.java:17）在org.junit.runners.ParentRunner.runLeaf（ParentRunner.java:325）在org.junit.runners.BlockJUnit4ClassRunner.runChild（BlockJUnit4ClassRunner.java:78）在org.junit.runners.BlockJUnit4ClassRunner.runChild（BlockJUnit4ClassRunner.java:57）在org.junit.runners.ParentRunner $ 3.run（ParentRunner.java:290）在org.junit.runners.ParentRunner $ 1.schedule（ParentRunner.java:71）在org.junit.runners.ParentRunner.runChildren（ParentRunner.java:288）在org.junit.runners.ParentRunner.access $ 000（ParentRunner.java:58）在org.junit.runners.ParentRunner上$ 2.evaluate（ParentRunner.java:268）在org.junit.internal.runners.statements.RunBefores.evaluate（RunBefores.java:26）在org.junit.runners.ParentRunner.run（ParentRunner.java:363）在org.junit.runner.JUnitCore.run（JUnitCore.java:137）在com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs（JUnit4IdeaTestRunner.java:68）在com.intellij.rt.execution.junit.IdeaTestRunner $ Repeater.startRunnerWithArgs（IdeaTestRunner.java:47）在com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart（JUnitStarter.java:242）在com.intellij.rt.execution.junit.JUnitStarter.main（JUnitStarter.java:70）

我不知道如何使用fastxml解析此对象？！

我的POJO对象模型如下：

@EqualsAndHashCode
@ToString
@Getter
@Builder
public class WsOrderReply {

    private final String topic;
    private final Message message;
    private final Long timestamp;

    @JsonCreator
    public WsOrderReply(
            @JsonProperty("topic") String topic,
            @JsonProperty("message") Message message,
            @JsonProperty("timestamp") Long timestamp) {
        this.topic = topic;
        this.message = message;
        this.timestamp = timestamp;
    }
}

@EqualsAndHashCode
@ToString
@Getter
public class Message {

    private final String entryType;
    private final BigDecimal rate;
    private final String action;
    private final String offerId;
    private final String market;
    private final State state;

    @JsonCreator
    public Message(
            @JsonProperty("entryType") String entryType,
            @JsonProperty("rate") BigDecimal rate,
            @JsonProperty("action") String action,
            @JsonProperty("offerId") String offerId,
            @JsonProperty("market") String market,
            @JsonProperty("state") State state) {
        this.entryType = entryType;
        this.rate = rate;
        this.action = action;
        this.offerId = offerId;
        this.market = market;
        this.state = state;
    }
}

@EqualsAndHashCode
@ToString
@Getter
public class State {

    private final String market;
    private final String offerType;
    private final String id;
    private final BigDecimal currentAmount;
    private final BigDecimal lockedAmount;
    private final BigDecimal rate;
    private final BigDecimal startAmount;
    private final String time;
    private final boolean postOnly;
    private final boolean hidden;
    private final String mode;
    private final BigDecimal receivedAmount;

    public State(
            @JsonProperty("market") String market,
            @JsonProperty("offerType") String offerType,
            @JsonProperty("id") String id,
            @JsonProperty("currentAmount") BigDecimal currentAmount,
            @JsonProperty("lockedAmount") BigDecimal lockedAmount,
            @JsonProperty("rate") BigDecimal rate,
            @JsonProperty("startAmount") BigDecimal startAmount,
            @JsonProperty("time") String time,
            @JsonProperty("postOnly") boolean postOnly,
            @JsonProperty("hidden") boolean hidden,
            @JsonProperty("mode") String mode,
            @JsonProperty("receivedAmount") BigDecimal receivedAmount) {
        this.market = market;
        this.offerType = offerType;
        this.id = id;
        this.currentAmount = currentAmount;
        this.lockedAmount = lockedAmount;
        this.rate = rate;
        this.startAmount = startAmount;
        this.time = time;
        this.postOnly = postOnly;
        this.hidden = hidden;
        this.mode = mode;
        this.receivedAmount = receivedAmount;
    }
}

我收到的原始json消息：

{ “ topic”：“交易/报价/ BTC-PLN”， “ message”：“ {\” entryType \“：\” Buy \“，\” rate \“：\” 22000.0 \“，\” action \“：\” update \“，\” offerId \“：\” b96f2da7-55f9-4221-aaa3-8e3ad177567d \“，\”市场\“：\” BTC-PLN \“，\”状态\“：{\”市场\“：\” BTC-PLN \“，\” offerType \“：\”购买\“，\” id \“：\” b96f2da7-55f9-4221-aaa3-8e3ad177567d \“，\” currentAmount \“：\” 0.0005 \“，\” lockedAmount \“：\” 11.00 \“，\” rate \“：\” 22000.0 \“，\” startAmount \“：\” 0.0005 \“，\” time \“：\” 1535023208260 \“，\” postOnly \“：false，\”隐藏\“：false，\” mode \“：\” limit \“，\” receivedAmount \“：\” 0 \“}}”， “时间戳记”：1535023208264 }

我的JUnit测试：

public class ReplyMapperTest {

    private static ObjectMapper objectMapper;

    private MessageFactory msgFactory = new quickfix.fix42.MessageFactory();

    private TypeSelector fixMsgBuilder = FixMessageBuilder
            .usingFactory(msgFactory::create)
            .withBeginString(FixVersions.BEGINSTRING_FIX42);

    private ReplyMapper replyMapper = new ReplyMapper(objectMapper, fixMsgBuilder);

    @BeforeClass
    public static void beforeClass() {
        objectMapper = new ObjectMapper();
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

    }

    @Test
    public void shouldMapUpdateOrderReplyNew() throws FieldNotFound, IOException {
        String json = IOUtils.toString(this.getClass().getResourceAsStream("/json/UpdateOrderReplyNew.json"), StandardCharsets.UTF_8);

        //When
        List<Message> result = replyMapper.apply(json);

        //Then
        assertThat(result.get(0).getHeader().getString(MsgType.FIELD), is(Heartbeat.MSGTYPE));
    }

也许有人也和我有同样的问题。如何解决呢？

Answer 1

即使未转义，您使用的JSON也不正确因此，它将整个对象视为一个字符串。使用正确的转义json将解决此问题，我已经更正了JSON，以便您现在就可以使用它

{\r\n\t\"topic\": \"trading\/offers\/BTC-PLN\",\r\n\t\"message\": {\r\n\t\t\"entryType\": \"Buy\",\r\n\t\t\"rate\": \"22000.0\",\r\n\t\t\"action\": \"update\",\r\n\t\t\"offerId\": \"b96f2da7-55f9-4221-aaa3-8e3ad177567d\",\r\n\t\t\"market\": \"BTC-PLN\",\r\n\t\t\"state\": {\r\n\t\t\t\"market\": \"BTC-PLN\",\r\n\t\t\t\"offerType\": \"Buy\",\r\n\t\t\t\"id\": \"b96f2da7-55f9-4221-aaa3-8e3ad177567d\",\r\n\t\t\t\"currentAmount\": \"0.0005\",\r\n\t\t\t\"lockedAmount\": \"11.00\",\r\n\t\t\t\"rate\": \"22000.0\",\r\n\t\t\t\"startAmount\": \"0.0005\",\r\n\t\t\t\"time\": \"1535023208260\",\r\n\t\t\t\"postOnly\": false,\r\n\t\t\t\"hidden\": false,\r\n\t\t\t\"mode\": \"limit\",\r\n\t\t\t\"receivedAmount\": \"0\"\r\n\t\t}\r\n\t},\r\n\t\"timestamp\": 1535023208264\r\n}

如果无法更改Json，则需要在构造函数中获取消息作为String值，然后使用对象映射器将其显式转换为对象

public class WsOrderReply {

        private final String topic;
        private final Message message;
        private final Long timestamp;
        ObjectMapper mapper = new ObjectMapper();

        @JsonCreator
        public WsOrderReply(
                @JsonProperty("topic") String topic,
                @JsonProperty("message") String messageString,
                @JsonProperty("timestamp") Long timestamp) {
            this.topic = topic;
            this.message = mapper.readValue(messageString, Message.class);;
            this.timestamp = timestamp;
        }
    }

另一种无需更改模型类即可工作的解决方案是从服务器获取JSON，然后将其本地更改为第一种方法中提到的格式

com.fasterxml.jackson.databind.exc.MismatchedInputException，同时使用fastxml

1 个答案: