Question

我使用Jackson对象映射器实现如下：

public void getFilterTest(){
    String filterJSON = "{\"SelectOptions\":[{\"key\":\"status\",\"options\":[{\"sign\":\"eq\",\"value\":\"FAILED\"},{\"sign\":\"eq\",\"value\":\"ESCALATED\"}]}]}";
    ObjectMapper objectMapper = new ObjectMapper();
    FilterModel filters = null;
    try {
        filters = objectMapper.convertValue(filterJSON, FilterModel.class);
    }catch(Exception e) {
        e.printStackTrace();
    }
    assertNotNull(filters);}

执行convertValue时出现以下错误：

java.lang.IllegalArgumentException：无法构造的实例 com.Test.FilterModel（尽管位于至少存在一个创建者）：没有字符串参数构造函数/工厂从字符串值反序列化的方法（'{“ SelectOptions”：[{“ key”：“ status”，“ options”：[{“ sign”：“ eq”，“ value”：“ FAILED”}，{“ sign”：“ eq”，“ value“：” ESCALATED“}]}}}''）在[资料来源：未知；行：-1，列：-1]在 com.fasterxml.jackson.databind.ObjectMapper._convert（ObjectMapper.java:3750）在 com.fasterxml.jackson.databind.ObjectMapper.convertValue（ObjectMapper.java:3668）在 com.test.util.TestUnitCPIODataUtil.getFilterTest（TestUnitCPIODataUtil.java:71）在sun.reflect.NativeMethodAccessorImpl.invoke0（本机方法）处 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.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate（RunBeforeTestExecutionCallbacks.java:74）在 org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate（RunAfterTestExecutionCallbacks.java:84）在 org.junit.internal.runners.statements.RunBefores.evaluate（RunBefores.java:26）在 org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate（RunBeforeTestMethodCallbacks.java:75）在 org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate（RunAfterTestMethodCallbacks.java:86）在 org.springframework.test.context.junit4.statements.SpringRepeat.evaluate（SpringRepeat.java:84）在org.junit.runners.ParentRunner.runLeaf（ParentRunner.java:325）处 org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild（SpringJUnit4ClassRunner.java:251）在 org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild（SpringJUnit4ClassRunner.java:97）在org.junit.runners.ParentRunner处$ 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 $ 2.evaluate（ParentRunner.java:268）在 org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate（RunBeforeTestClassCallbacks.java:61）在 org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate（RunAfterTestClassCallbacks.java:70）在org.junit.runners.ParentRunner.run（ParentRunner.java:363）处 org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run（SpringJUnit4ClassRunner.java:190）在 org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run（JUnit4TestReference.java:86）在 org.eclipse.jdt.internal.junit.runner.TestExecution.run（TestExecution.java:38）在 org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests（RemoteTestRunner.java:538）在 org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests（RemoteTestRunner.java:760）在 org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run（RemoteTestRunner.java:460）在 org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main（RemoteTestRunner.java:206）造成原因： com.fasterxml.jackson.databind.exc.MismatchedInputException：无法构造的实例 com.test.FilterModel（尽管位于至少存在一个创建者）：没有字符串参数构造函数/工厂从字符串值反序列化的方法（'{“ SelectOptions”：[{“ key”：“ status”，“ options”：[{“ sign”：“ eq”，“ value”：“ FAILED”}，{“ sign”：“ eq”，“ value“：” ESCALATED“}]}}}''）在[资料来源：未知；行：-1，列：-1]在 com.fasterxml.jackson.databind.exc.MismatchedInputException.from（MismatchedInputException.java:63）在 com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch（DeserializationContext.java:1343）在 com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator（DeserializationContext.java:1032）在 com.fasterxml.jackson.databind.deser.ValueInstantiator._createFromStringFallbacks（ValueInstantiator.java:371）在 com.fasterxml.jackson.databind.deser.std.StdValueInstantiator.createFromString（StdValueInstantiator.java:323）在 com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromString（BeanDeserializerBase.java:1373）在 com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeOther（BeanDeserializer.java:171）在 com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize（BeanDeserializer.java:161）在 com.fasterxml.jackson.databind.ObjectMapper._convert（ObjectMapper.java:3745） ...另外34个

这是我的模型课：过滤器型号：

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
"SelectOptions"
})
public class FilterModel {

@JsonProperty("SelectOptions")
private List<SelectOption> selectOptions = null;
@JsonIgnore
private Map<String, Object> additionalProperties = new HashMap<String, Object>();

@JsonProperty("SelectOptions")
public List<SelectOption> getSelectOptions() {
return selectOptions;
}

@JsonProperty("SelectOptions")
public void setSelectOptions(List<SelectOption> selectOptions) {
this.selectOptions = selectOptions;
}

@JsonAnyGetter
public Map<String, Object> getAdditionalProperties() {
return this.additionalProperties;
}

@JsonAnySetter
public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}

}

SelectOptions类：

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
"key",
"options"
})
public class SelectOption {

@JsonProperty("key")
private String key;
@JsonProperty("options")
private List<Option> options = null;
@JsonIgnore
private Map<String, Object> additionalProperties = new HashMap<String, Object>();

@JsonProperty("key")
public String getKey() {
return key;
}

@JsonProperty("key")
public void setKey(String key) {
this.key = key;
}

@JsonProperty("options")
public List<Option> getOptions() {
return options;
}

@JsonProperty("options")
public void setOptions(List<Option> options) {
this.options = options;
}

@JsonAnyGetter
public Map<String, Object> getAdditionalProperties() {
return this.additionalProperties;
}

@JsonAnySetter
public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}

}

选项模型类：

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
"sign",
"value"
})
public class Option {

@JsonProperty("sign")
private String sign;
@JsonProperty("value")
private String value;
@JsonIgnore
private Map<String, Object> additionalProperties = new HashMap<String, Object>();

@JsonProperty("sign")
public String getSign() {
return sign;
}

@JsonProperty("sign")
public void setSign(String sign) {
this.sign = sign;
}

@JsonProperty("value")
public String getValue() {
return value;
}

@JsonProperty("value")
public void setValue(String value) {
this.value = value;
}

@JsonAnyGetter
public Map<String, Object> getAdditionalProperties() {
return this.additionalProperties;
}

@JsonAnySetter
public void setAdditionalProperty(String name, Object value) {
this.additionalProperties.put(name, value);
}

}

我在其他问题上尝试了几种解决方案，但找不到解决方案。似乎整个JSON字符串都被视为普通字符串。但是，我不确定该如何解决。我需要FilterModel类，因为我希望有1个以上的参数，这与上述测试用例中的字符串不同。

Answer 1

您应该调用 readValue 方法。

filters = objectMapper.readValue(filterJSON, FilterModel.class);

Answer 2

final List<Object> providers = new ArrayList<Object>();

JacksonJaxbJsonProvider jacksonJsonProvider = new JacksonJaxbJsonProvider();
        providers.add( jacksonJsonProvider );

WebClient client =  WebClient.create(node + updateCacheNodeUrl, providers);
                      client.type("application/json").accept("application/json")
try {
                            ObjectMapper objectMapper = new ObjectMapper();
                            
                            objectMapper.enable(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY);
                            String serialisedJson = objectMapper.writeValueAsString(replicateCacheDto);
                            ReplicateCacheDto objReplicateCacheDto = objectMapper.readValue(serialisedJson, ReplicateCacheDto.class);
                            System.out.println("objReplicateCacheDto.toString = " + objReplicateCacheDto.toString());
                            
                            client.put(objReplicateCacheDto);
                        } catch (JsonParseException e) {
                            e.printStackTrace();
                        }
                      catch (Exception e) {
                            e.printStackTrace();
                        }

无法构造“ com.test.FilterModel”的实例。没有可从字符串值反序列化的字符串参数构造函数/工厂方法

2 个答案: