您如何使用 Jackson 将 Java Map 转换为组合的 POJO？
How do you use Jackson to convert a Java Map to a composed POJO?
我一直在试验更可靠的方法来解析来自 Conductor 工作流的输入。为此，我创建了一个包含一个人和他们的车辆的组合 class 结构。
Person.java
public class Person {
protected String firstName;
protected String lastName;
protected List<Vehicle> vehicles;
// Constructors, getters, setters
}
Vehicle.java
public class Vehicle {
public String make;
public String model;
public String trim;
public short year;
// Constructors, getters, setters
}
然后我创建了一个 worker，它使用 Jackson 将 Conductor Client 的 Task.getInputData() Map 转换为上述 POJO。
ExperimentalStepWorker.java
public class ExperimentStepWorker implements Worker {
protected ObjectMapper objectMapper = new ObjectMapper();
// Other @Overloaded methods per the Worker interface
/**
* Executes a task and returns the updated task.
*
* @param task Task to be executed.
* @return the {@link TaskResult} object
* If the task is not completed yet, return with the status as IN_PROGRESS.
*/
@Override
public TaskResult execute(Task task) {
TaskResult result = new TaskResult(task);
Person person = objectMapper.convertValue(task.getInputData(), Person.class);
System.out.println("The map's contents were:");
System.out.println(task.getInputData());
System.out.println();
System.out.println("The objects's contents were:");
System.out.println(person);
result.setStatus(TaskResult.Status.COMPLETED);
return result;
}
}
然后我将以下工作流提交给了 Conductor。第一个没有输入。第二个只有一个 Person 对象，最后一个也是最后一个有三个车辆的数组：
从 Postman 到 Conductor Server 的工作流输入
{
"name": "see_if_jackson_works",
"workflowDef": {
"ownerApp": "postman",
"createdBy": "postman_user",
"name": "do_all_the_things_2",
"description": "Test Http Task Workflow",
"version": 1,
"tasks": [
{
"name": "worker_1",
"taskReferenceName": "First Experiment",
"inputParameters": {},
"type": "SIMPLE",
"startDelay": 15,
"optional": false
},
{
"name": "worker_2",
"taskReferenceName": "Second Experiment",
"inputParameters": {
"firstName": "Kirkland",
"lastName": "Yuknis"
},
"type": "SIMPLE",
"startDelay": 30,
"optional": false
},
{
"name": "worker_3",
"taskReferenceName": "Third experiment",
"inputParameters": {
"firstName": "Kirkland",
"lastName": "Yuknis",
"vehicles": [
{"make": "Subaru", "model": "Outback", "trim": "Limited", "year": 2018},
{"make": "Subaru", "model": "Outback", "trim": "Limited", "year": 2018},
{"make": "Subaru", "model": "Outback", "trim": "Limited", "year": 2018}
]
},
"type": "SIMPLE",
"startDelay": 45,
"optional": false
}
],
"schemaVersion": 2,
"restartable": true,
"workflowStatusListenerEnabled": false
},
"input": {}
}
前两个实验似乎运行良好，但在最后一个实验中，Conductor 未能执行任务。阅读文档后，我想知道是否可以将组合对象作为 Conductor 任务的输入。有谁能证实或否认这一点？如果可以的话，我可能哪里做错了？
服务器调用worker时execute()方法的Worker输出
The map's contents were:
{}
The objects's contents were:
Person{firstName='null', lastName='null', vehicles=null}
The map's contents were:
{firstName=Kirkland, lastName=Yuknis}
The objects's contents were:
Person{firstName='Kirkland', lastName='Yuknis', vehicles=null}
更新：我刚刚发现了以下错误，看起来像是 Jackson 的问题
{
"taskType": "worker_3",
"status": "FAILED",
"inputData": {
"firstName": "Kirkland",
"lastName": "Yuknis",
"vehicles": [
{
"make": "Subaru",
"model": "Outback",
"trim": "Limited",
"Year": 2018
},
{
"make": "Subaru",
"model": "Outback",
"trim": "Limited",
"Year": 2018
},
{
"make": "Subaru",
"model": "Outback",
"trim": "Limited",
"Year": 2018
}
]
},
"referenceTaskName": "Third experiment",
"retryCount": 0,
"seq": 3,
"pollCount": 1,
"taskDefName": "worker_3",
"scheduledTime": 1559838042119,
"startTime": 1559838087887,
"endTime": 1559838088012,
"updateTime": 1559838087888,
"startDelayInSeconds": 45,
"retried": true,
"executed": false,
"callbackFromWorker": true,
"responseTimeoutSeconds": 1200,
"workflowInstanceId": "08a7bf21-6f4b-4265-97b0-0ce9cc93d1a4",
"workflowType": "do_all_the_things_2",
"taskId": "3b4906df-7136-4669-a8c8-a12a9b7c2f6a",
"reasonForIncompletion": "Error while executing the task: java.lang.IllegalArgumentException: Unrecognized field \"vehicles\" (class com.yuknis.egypt.models.Person), not marked as ignorable (2 known properties: \"lastName\", \"firstName\"])\n at [Source: UNKNOWN; line: -1, column: -1] (through reference chain: com.yuknis.egypt.models.Person[\"vehicles\"])",
"callbackAfterSeconds": 0,
"workerId": "Kirklands-MBP.hsd1.fl.comcast.net",
"workflowTask": {
"name": "worker_3",
"taskReferenceName": "Third experiment",
"inputParameters": {
"firstName": "Kirkland",
"lastName": "Yuknis",
"vehicles": [
{
"make": "Subaru",
"model": "Outback",
"trim": "Limited",
"Year": 2018
},
{
"make": "Subaru",
"model": "Outback",
"trim": "Limited",
"Year": 2018
},
{
"make": "Subaru",
"model": "Outback",
"trim": "Limited",
"Year": 2018
}
]
},
"type": "SIMPLE",
"startDelay": 45,
"optional": false,
"taskDefinition": {
"createTime": 1559837812844,
"name": "worker_3",
"retryCount": 3,
"timeoutSeconds": 0,
"timeoutPolicy": "TIME_OUT_WF",
"retryLogic": "FIXED",
"retryDelaySeconds": 600,
"responseTimeoutSeconds": 1200,
"concurrentExecLimit": 100,
"rateLimitPerFrequency": 50,
"rateLimitFrequencyInSeconds": 60
},
"asyncComplete": false
},
"rateLimitPerFrequency": 0,
"rateLimitFrequencyInSeconds": 0,
"taskDefinition": {
"present": true
},
"queueWaitTime": 45768,
"taskStatus": "FAILED",
"logs": [
"06/06/19, 16:21:28:008 : java.lang.IllegalArgumentException: Unrecognized field \"vehicles\" (class com.yuknis.egypt.models.Person), not marked as ignorable (2 known properties: \"lastName\", \"firstName\"])\n at [Source: UNKNOWN; line: -1, column: -1] (through reference chain: com.yuknis.egypt.models.Person[\"vehicles\"])\n\tat com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:3750)\n\tat com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:3668)\n\tat com.yuknis.egypt.workers.ExperimentStepWorker.execute(ExperimentStepWorker.java:58)\n\tat com.netflix.conductor.client.task.WorkflowTaskCoordinator.execute(WorkflowTaskCoordinator.java:379)\n\tat com.netflix.conductor.client.task.WorkflowTaskCoordinator.lambda$pollForTask(WorkflowTaskCoordinator.java:340)\n\tat java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)\n\tat java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)\n\tat java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)\n\tat java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)\n\tat java.base/java.lang.Thread.run(Thread.java:835)\nCaused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field \"vehicles\" (class com.yuknis.egypt.models.Person), not marked as ignorable (2 known properties: \"lastName\", \"firstName\"])\n at [Source: UNKNOWN; line: -1, column: -1] (through reference chain: com.yuknis.egypt.models.Person[\"vehicles\"])\n\tat com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:61)\n\tat com.fasterxml.jackson.databind.DeserializationContext.handleUnknownProperty(DeserializationContext.java:823)\n\tat com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:1153)\n\tat com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1589)\n\tat com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownVanilla(BeanDeserializerBase.java:1567)\n\tat com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:294)\n\tat com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151)\n\tat com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:3745)\n\t... 9 more\n"
]
},
我发现了问题。作为一种习惯，我不会为 class 上的 non-primitive 数据成员创建访问器。由于 List 是 non-primitive，我（想都没想）没有为它创建访问器。除此之外，车辆受到保护而不是 public。我已经添加了访问器，它解决了这个问题。感谢所有看过这篇文章的人！
我一直在试验更可靠的方法来解析来自 Conductor 工作流的输入。为此，我创建了一个包含一个人和他们的车辆的组合 class 结构。
Person.java
public class Person {
protected String firstName;
protected String lastName;
protected List<Vehicle> vehicles;
// Constructors, getters, setters
}
Vehicle.java
public class Vehicle {
public String make;
public String model;
public String trim;
public short year;
// Constructors, getters, setters
}
然后我创建了一个 worker，它使用 Jackson 将 Conductor Client 的 Task.getInputData() Map 转换为上述 POJO。
ExperimentalStepWorker.java
public class ExperimentStepWorker implements Worker {
protected ObjectMapper objectMapper = new ObjectMapper();
// Other @Overloaded methods per the Worker interface
/**
* Executes a task and returns the updated task.
*
* @param task Task to be executed.
* @return the {@link TaskResult} object
* If the task is not completed yet, return with the status as IN_PROGRESS.
*/
@Override
public TaskResult execute(Task task) {
TaskResult result = new TaskResult(task);
Person person = objectMapper.convertValue(task.getInputData(), Person.class);
System.out.println("The map's contents were:");
System.out.println(task.getInputData());
System.out.println();
System.out.println("The objects's contents were:");
System.out.println(person);
result.setStatus(TaskResult.Status.COMPLETED);
return result;
}
}
然后我将以下工作流提交给了 Conductor。第一个没有输入。第二个只有一个 Person 对象，最后一个也是最后一个有三个车辆的数组：
从 Postman 到 Conductor Server 的工作流输入
{
"name": "see_if_jackson_works",
"workflowDef": {
"ownerApp": "postman",
"createdBy": "postman_user",
"name": "do_all_the_things_2",
"description": "Test Http Task Workflow",
"version": 1,
"tasks": [
{
"name": "worker_1",
"taskReferenceName": "First Experiment",
"inputParameters": {},
"type": "SIMPLE",
"startDelay": 15,
"optional": false
},
{
"name": "worker_2",
"taskReferenceName": "Second Experiment",
"inputParameters": {
"firstName": "Kirkland",
"lastName": "Yuknis"
},
"type": "SIMPLE",
"startDelay": 30,
"optional": false
},
{
"name": "worker_3",
"taskReferenceName": "Third experiment",
"inputParameters": {
"firstName": "Kirkland",
"lastName": "Yuknis",
"vehicles": [
{"make": "Subaru", "model": "Outback", "trim": "Limited", "year": 2018},
{"make": "Subaru", "model": "Outback", "trim": "Limited", "year": 2018},
{"make": "Subaru", "model": "Outback", "trim": "Limited", "year": 2018}
]
},
"type": "SIMPLE",
"startDelay": 45,
"optional": false
}
],
"schemaVersion": 2,
"restartable": true,
"workflowStatusListenerEnabled": false
},
"input": {}
}
前两个实验似乎运行良好，但在最后一个实验中，Conductor 未能执行任务。阅读文档后，我想知道是否可以将组合对象作为 Conductor 任务的输入。有谁能证实或否认这一点？如果可以的话，我可能哪里做错了？
服务器调用worker时execute()方法的Worker输出
The map's contents were:
{}
The objects's contents were:
Person{firstName='null', lastName='null', vehicles=null}
The map's contents were:
{firstName=Kirkland, lastName=Yuknis}
The objects's contents were:
Person{firstName='Kirkland', lastName='Yuknis', vehicles=null}
更新：我刚刚发现了以下错误，看起来像是 Jackson 的问题
{
"taskType": "worker_3",
"status": "FAILED",
"inputData": {
"firstName": "Kirkland",
"lastName": "Yuknis",
"vehicles": [
{
"make": "Subaru",
"model": "Outback",
"trim": "Limited",
"Year": 2018
},
{
"make": "Subaru",
"model": "Outback",
"trim": "Limited",
"Year": 2018
},
{
"make": "Subaru",
"model": "Outback",
"trim": "Limited",
"Year": 2018
}
]
},
"referenceTaskName": "Third experiment",
"retryCount": 0,
"seq": 3,
"pollCount": 1,
"taskDefName": "worker_3",
"scheduledTime": 1559838042119,
"startTime": 1559838087887,
"endTime": 1559838088012,
"updateTime": 1559838087888,
"startDelayInSeconds": 45,
"retried": true,
"executed": false,
"callbackFromWorker": true,
"responseTimeoutSeconds": 1200,
"workflowInstanceId": "08a7bf21-6f4b-4265-97b0-0ce9cc93d1a4",
"workflowType": "do_all_the_things_2",
"taskId": "3b4906df-7136-4669-a8c8-a12a9b7c2f6a",
"reasonForIncompletion": "Error while executing the task: java.lang.IllegalArgumentException: Unrecognized field \"vehicles\" (class com.yuknis.egypt.models.Person), not marked as ignorable (2 known properties: \"lastName\", \"firstName\"])\n at [Source: UNKNOWN; line: -1, column: -1] (through reference chain: com.yuknis.egypt.models.Person[\"vehicles\"])",
"callbackAfterSeconds": 0,
"workerId": "Kirklands-MBP.hsd1.fl.comcast.net",
"workflowTask": {
"name": "worker_3",
"taskReferenceName": "Third experiment",
"inputParameters": {
"firstName": "Kirkland",
"lastName": "Yuknis",
"vehicles": [
{
"make": "Subaru",
"model": "Outback",
"trim": "Limited",
"Year": 2018
},
{
"make": "Subaru",
"model": "Outback",
"trim": "Limited",
"Year": 2018
},
{
"make": "Subaru",
"model": "Outback",
"trim": "Limited",
"Year": 2018
}
]
},
"type": "SIMPLE",
"startDelay": 45,
"optional": false,
"taskDefinition": {
"createTime": 1559837812844,
"name": "worker_3",
"retryCount": 3,
"timeoutSeconds": 0,
"timeoutPolicy": "TIME_OUT_WF",
"retryLogic": "FIXED",
"retryDelaySeconds": 600,
"responseTimeoutSeconds": 1200,
"concurrentExecLimit": 100,
"rateLimitPerFrequency": 50,
"rateLimitFrequencyInSeconds": 60
},
"asyncComplete": false
},
"rateLimitPerFrequency": 0,
"rateLimitFrequencyInSeconds": 0,
"taskDefinition": {
"present": true
},
"queueWaitTime": 45768,
"taskStatus": "FAILED",
"logs": [
"06/06/19, 16:21:28:008 : java.lang.IllegalArgumentException: Unrecognized field \"vehicles\" (class com.yuknis.egypt.models.Person), not marked as ignorable (2 known properties: \"lastName\", \"firstName\"])\n at [Source: UNKNOWN; line: -1, column: -1] (through reference chain: com.yuknis.egypt.models.Person[\"vehicles\"])\n\tat com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:3750)\n\tat com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:3668)\n\tat com.yuknis.egypt.workers.ExperimentStepWorker.execute(ExperimentStepWorker.java:58)\n\tat com.netflix.conductor.client.task.WorkflowTaskCoordinator.execute(WorkflowTaskCoordinator.java:379)\n\tat com.netflix.conductor.client.task.WorkflowTaskCoordinator.lambda$pollForTask(WorkflowTaskCoordinator.java:340)\n\tat java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)\n\tat java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)\n\tat java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)\n\tat java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)\n\tat java.base/java.lang.Thread.run(Thread.java:835)\nCaused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field \"vehicles\" (class com.yuknis.egypt.models.Person), not marked as ignorable (2 known properties: \"lastName\", \"firstName\"])\n at [Source: UNKNOWN; line: -1, column: -1] (through reference chain: com.yuknis.egypt.models.Person[\"vehicles\"])\n\tat com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:61)\n\tat com.fasterxml.jackson.databind.DeserializationContext.handleUnknownProperty(DeserializationContext.java:823)\n\tat com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:1153)\n\tat com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1589)\n\tat com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownVanilla(BeanDeserializerBase.java:1567)\n\tat com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:294)\n\tat com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151)\n\tat com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:3745)\n\t... 9 more\n"
]
},
我发现了问题。作为一种习惯，我不会为 class 上的 non-primitive 数据成员创建访问器。由于 List 是 non-primitive，我（想都没想）没有为它创建访问器。除此之外，车辆受到保护而不是 public。我已经添加了访问器，它解决了这个问题。感谢所有看过这篇文章的人！