假设我打电话给第三方API以获取对象任务，我得到以下JSON字符串作为回报：
{
"tasks": [
{
"id": 1,
"code": "CODE",
"description": "Dummy Task",
"withConfirmation": false,
"resource": {
"id": "abcdef12-fe14-57c4-acb5-1234e7456d62",
"group": "Doctor",
"firstname": "Toto",
"lastname": "Wallace",
},
{
"id": 2,
"code": "CODE",
"description": "Dummyyy Taaask",
"withConfirmation": false
}
]
}
在返回的json中，我们有任务，可以使用资源加入。
在我们的系统中，任务如下所示：
@JsonAutoDetect
public class Task implements Serializable {
private Integer id;
private String code = "BASIC";
private String description;
private boolean withConfirmation = false;
/**
* CONSTRUCTOR
*/
public Task() {
}
public Integer getId() {
return id;
}
@JsonProperty
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
@JsonProperty
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
@JsonProperty
public boolean isWithConfirmation() {
return withConfirmation;
}
public void setWithConfirmation(boolean withConfirmation) {
this.withConfirmation = withConfirmation;
}
public String toString() {...
}
}
和资源看起来像这样：
public class Resource implements Serializable {
...
private String firstname;
private String lastname;
private MedicalGroup group; // id + name + description
private Set<Task> tasks = new HashSet<Task>(0);
...
// getters and setters and toString etc.
...
}
因此，除了字段名称之外，主要区别在于任务不包含任何资源，但关系方向相反，这意味着< em>资源可以保存 n 任务。
对于这种情况，从第三方序列化返回的json对象并将其转换/映射到我自己系统的pojo的最佳方法是什么？ 我目前正在阅读Gson doc以试用它，但欢迎提出任何建议。 此代码必须易于重复使用，因为在多个项目中需要它。
答案 0 :(得分：1)
这不是完整的工作代码，因为我不知道您希望如何使用Resource。 Json应该创建新资源还是尝试查找已存在的资源。你将如何从json创建MedicalGroup，因为它不是enuogh数据。我会在评论中问这个，但没有足够的空间。以下是演示如何尝试解决除Resources to/from json映射之外的大多数问题。
主要想法是在@JsonAnyGetter public Map<String, Object> getAdditionalProperties() POJO中添加@JsonAnySetter public void setAdditionalProperty(String name, Resource value)和Task：
@JsonAnyGetter
public Map<String, Object> getAdditionalProperties() {
HashMap<String, Object> map= new HashMap<>();
// IMPORTANT
// here we can try to find resource that has this task
// and export its info to json like this:
// CHANGE THIS
Resource res = new Resource();
res.firstname = "Toto";
res.lastname = "Wallace";
// IMPORTANT END
map.put("resource", res);
return map;
}
@JsonAnySetter
public void setAdditionalProperty(String name, Resource value) {
// IMPORTANT
// Here you have to create or find appropriate Resource in your code
// and add current task to it
System.out.println(name+" "+ value );
}
完整演示：
import com.fasterxml.jackson.annotation.*;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.IOException;
import java.io.Serializable;
import java.util.*;
public class Main3 {
private static String json = "{\n" +
" \"tasks\": [\n" +
" {\n" +
" \"id\": 1,\n" +
" \"code\": \"CODE\",\n" +
" \"description\": \"Dummy Task\",\n" +
" \"withConfirmation\": false,\n" +
" \"resource\": {\n" +
" \"id\": \"abcdef12-fe14-57c4-acb5-1234e7456d62\",\n" +
" \"group\": \"Doctor\",\n" +
" \"firstname\": \"Toto\",\n" +
" \"lastname\": \"Wallace\"\n" +
" }},\n" +
" {\n" +
" \"id\": 2,\n" +
" \"code\": \"CODE\",\n" +
" \"description\": \"Dummyyy Taaask\",\n" +
" \"withConfirmation\": false\n" +
" }\n" +
" ]\n" +
" }";
public static void main(String[] args) throws IOException {
ObjectMapper mapper = new ObjectMapper();
TasksList tl = mapper.readValue(json, TasksList.class);
String result = mapper.writeValueAsString(tl);
System.out.println(result);
}
private static class TasksList {
@JsonProperty(value = "tasks")
private List<Task> tasks;
}
@JsonIgnoreProperties(ignoreUnknown = true)
public static class Resource implements Serializable {
@JsonProperty(value = "firstname")
private String firstname;
@JsonProperty(value = "lastname")
private String lastname;
// HAVE NO IDEA HOW YOU GONNA MAP THIS TO JSON
// private MedicalGroup group; // id + name + description
private Set<Task> tasks = new HashSet<Task>(0);
@Override
public String toString() {
return "Resource{" +
"firstname='" + firstname + '\'' +
", lastname='" + lastname + '\'' +
", tasks=" + tasks +
'}';
}
}
@JsonAutoDetect
public static class Task implements Serializable {
private Integer id;
private String code = "BASIC";
private String description;
private boolean withConfirmation = false;
/**
* CONSTRUCTOR
*/
public Task() {
}
public Integer getId() {
return id;
}
@JsonProperty
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
@JsonProperty
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
@JsonProperty
public boolean isWithConfirmation() {
return withConfirmation;
}
public void setWithConfirmation(boolean withConfirmation) {
this.withConfirmation = withConfirmation;
}
@JsonAnyGetter
public Map<String, Object> getAdditionalProperties() {
HashMap<String, Object> map= new HashMap<>();
// IMPORTANT
// here we can try to find resource that has this task
// and export its info to json like this:
// CHANGE THIS
Resource res = new Resource();
res.firstname = "Toto";
res.lastname = "Wallace";
// IMPORTANT END
map.put("resource", res);
return map;
}
@JsonAnySetter
public void setAdditionalProperty(String name, Resource value) {
// IMPORTANT
// Probably here you have to create or find appropriate Resource in your code
// and add current task to it
System.out.println(name+" "+ value );
}
@Override
public String toString() {
return "Task{" +
"id=" + id +
", code='" + code + '\'' +
", description='" + description + '\'' +
", withConfirmation=" + withConfirmation +
'}';
}
}
}
答案 1 :(得分：0)
您可以通过Google使用git hash-object <important file>
库将Gson转换为Json。
Pojo Class