如何使用boon和rest将json文件解析为java？

Question

我正在尝试解析一个JSON文件，它是通过API到pojo获得的。在网上搜索之后，我看到布恩在休息，但我不知道怎么做。根据这个文章，它应该能工作，但是..。

在我的代码中，HTTP.getJSON()方法需要一个映射作为参数，而我不知道这个映射到底是什么。

任何一个天才都可以给出一个实惠的例子？

public class ViewTimeline{

    public void view() {
        ObjectMapper mapper = JsonFactory.create();
        List<String> read = IO.readLines("https://corona-api.com/timeline");

        Map<String, ?> headers = null ;
        List<Timeline> timelineList = mapper.readValue(HTTP.getJSON("https://corona-api.com/timeline", headers), List.class, Timeline.class);

    }
}

TimeLine.java

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@JsonInclude(JsonInclude.Include.NON_NULL)
@JsonPropertyOrder({
    "updated_at",
    "date",
    "deaths",
    "confirmed",
    "recovered",
    "active",
    "new_confirmed",
    "new_recovered",
    "new_deaths",
    "is_in_progress"
})
public class Timeline {

    @JsonProperty("updated_at")
    private String updatedAt;
    @JsonProperty("date")
    private String date;
    @JsonProperty("deaths")
    private Integer deaths;
    @JsonProperty("confirmed")
    private Integer confirmed;
    @JsonProperty("recovered")
    private Integer recovered;
    @JsonProperty("active")
    private Integer active;
    @JsonProperty("new_confirmed")
    private Integer newConfirmed;
    @JsonProperty("new_recovered")
    private Integer newRecovered;
    @JsonProperty("new_deaths")
    private Integer newDeaths;
    @JsonProperty("is_in_progress")
    private Boolean isInProgress;

    @JsonProperty("updated_at")
    public String getUpdatedAt() {
        return updatedAt;
    }

    @JsonProperty("updated_at")
    public void setUpdatedAt(String updatedAt) {
        this.updatedAt = updatedAt;
    }

    @JsonProperty("date")
    public String getDate() {
        return date;
    }

    @JsonProperty("date")
    public void setDate(String date) {
        this.date = date;
    }

    @JsonProperty("deaths")
    public Integer getDeaths() {
        return deaths;
    }

    @JsonProperty("deaths")
    public void setDeaths(Integer deaths) {
        this.deaths = deaths;
    }

    @JsonProperty("confirmed")
    public Integer getConfirmed() {
        return confirmed;
    }

    @JsonProperty("confirmed")
    public void setConfirmed(Integer confirmed) {
        this.confirmed = confirmed;
    }

    @JsonProperty("recovered")
    public Integer getRecovered() {
        return recovered;
    }

    @JsonProperty("recovered")
    public void setRecovered(Integer recovered) {
        this.recovered = recovered;
    }

    @JsonProperty("active")
    public Integer getActive() {
        return active;
    }

    @JsonProperty("active")
    public void setActive(Integer active) {
        this.active = active;
    }

    @JsonProperty("new_confirmed")
    public Integer getNewConfirmed() {
        return newConfirmed;
    }

    @JsonProperty("new_confirmed")
    public void setNewConfirmed(Integer newConfirmed) {
        this.newConfirmed = newConfirmed;
    }

    @JsonProperty("new_recovered")
    public Integer getNewRecovered() {
        return newRecovered;
    }

    @JsonProperty("new_recovered")
    public void setNewRecovered(Integer newRecovered) {
        this.newRecovered = newRecovered;
    }

    @JsonProperty("new_deaths")
    public Integer getNewDeaths() {
        return newDeaths;
    }

    @JsonProperty("new_deaths")
    public void setNewDeaths(Integer newDeaths) {
        this.newDeaths = newDeaths;
    }

    @JsonProperty("is_in_progress")
    public Boolean getIsInProgress() {
        return isInProgress;
    }

    @JsonProperty("is_in_progress")
    public void setIsInProgress(Boolean isInProgress) {
        this.isInProgress = isInProgress;
    }

}

Answer 1

为了将json解析为对象，我使用了Jackson。我还看到您在Timeline的映射中使用了Timeline。

杰克逊核心：https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core/2.11.0

杰克逊数据库：https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind/2.11.0

杰克逊注释：https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-annotations/2.11.0

我就是这样处理的：

public static void main(String[] args) throws JsonProcessingException {

    //my method to read content from website.
    //using apache http
    String jsonApi = getApi();

    ObjectMapper objectMapper = new ObjectMapper();

    //todo JsonProcessingException
    JsonNode data = objectMapper.readTree(jsonApi);

    //get data field from data, which is an array
    //todo This can throws error if data field is missing
    JsonNode dataArray = data.get("data");

    List<Timeline> timelineList = new ArrayList<>();
    if(dataArray.isArray()){

        for(JsonNode line : dataArray){

            //todo this can throws errors. need to handle it.
            Timeline timeline = objectMapper.readValue(line.toString(), Timeline.class);

            timelineList.add(timeline);

        }

    }else{
        System.out.println("JsonApi is not array: '" + jsonApi + "'");
    }

    System.out.println("Size: " + timelineList.size());
    for(Timeline timeline : timelineList){

        System.out.println(timeline.getConfirmed());

    }

}

在这段代码中，您应该处理异常。我用评论来标记它们。