遍历列表时如何返回所有值？ [关闭]

Question

public Details getDetails(String id) throws InvokerException { 详细信息 details = new Details();

try {

    URL url = new URL(BaseUrl, "/cxf/query/ask?id=" + id);
    LOGGER.trace("URL: {}", url);

    String xml = queryStore(url);
    LOGGER.trace("Query result: {}", xml);

    details = new Details();
    InputSrc source = new InputSrc(new StringReader(xml));
        ResultsContentHandler handler = new ResultsContentHandler();

    XMLReader reader = XMLReaderFactory.createXMLReader();
    reader.setContentHandler(handler);
    reader.parse(source);

    for (Hashtable<String,String> result : handler.getResultSet()) {
        String baseId = result.get("baseId");
        ArrayList<Details> list = getHistoryDetails(baseId );

        for(Details t : list) {
        details.setStatus(t.getStatus());
        }
    }
} catch (Exception e) {
    throw new InvokerException(e);
}
return details;

}

我想要实现的是返回 Arraylist 中所有项目的详细信息。例如，我希望获得多个状态，但目前我只获得一种状态。

细节类

public class Details {
    private Core core;
    private String department;
    private GregorianCalendar timestampReceived;
    private GregorianCalendar timestampReported;
    private String status;
    private GregorianCalendar timestampStatus;
    private String explanation;

    public Details(){}

    public Details(Core core,
            String department, GregorianCalendar timestampReceived,
            GregorianCalendar timestampReported, String status,
            GregorianCalendar timestampStatus, String explanation) {
        super();
        this.core = core;
        this.department = department;
        this.timestampReceived = timestampReceived;
        this.timestampReported = timestampReported;
        this.status = status;
        this.timestampStatus = timestampStatus;
        this.explanation = explanation;
    }
    public Core getCore() {
        return core;
    }

    public String getDepartment() {
        return department;
    }
    public GregorianCalendar getTimestampReceived() {
        return timestampReceived;
    }

    public GregorianCalendar getTimestampReported() {
        return timestampReported;
    }

    public String getStatus() {
        return status;
    }

    public GregorianCalendar getTimestampStatus() {
        return timestampStatus;
    }

    public String getExplanation() {
        return explanation;
    }

    public void setCore(Core core) {
        this.core = core;
    }

    public void setDepartment(String department) {
        this.department = department;
    }

    public void setTimestampReceived(GregorianCalendar timestampReceived) {
        this.timestampReceived = timestampReceived;
    }

    public void setTimestampReported(GregorianCalendar timestampReported) {
        this.timestampReported = timestampReported;
    }

    public void setStatus(String status) {
        this.status = status;
    }

    public void setTimestampStatus(GregorianCalendar timestampStatus) {
        this.timestampStatus = timestampStatus;
    }

    public void setExplanation(String explanation) {
        this.explanation = explanation;
    }


}

Answer 1

你不能在一个方法的调用中返回多个值，但是你应该做的是返回一个 ArrayList：

public List<Details> getDetails(String id) throws InvokerException {
    List<Details> details = new ArrayList<Details>();

    try {

        URL url = new URL(BaseUrl, "/cxf/query/ask?id=" + id);
        LOGGER.trace("URL: {}", url);

        String xml = queryStore(url);
        LOGGER.trace("Query result: {}", xml);

        InputSrc source = new InputSrc(new StringReader(xml));
            ResultsContentHandler handler = new ResultsContentHandler();

        XMLReader reader = XMLReaderFactory.createXMLReader();
        reader.setContentHandler(handler);
        reader.parse(source);

        Details detail;
        for (Hashtable<String,String> result : handler.getResultSet()) {
            String baseId = result.get("baseId");
            ArrayList<Details> list = getHistoryDetails(baseId );

            for(Details t : list) {
            detail = new Details();
            detail.setStatus(t.getStatus());
            details.add(detail);
            }
        }
    } catch (Exception e) {
        throw new InvokerException(e);
    }
    return details;
}

Answer 2

您需要返回List<Details>，而不仅仅是详细信息。因此，您希望在代码示例中返回变量“list”。

Answer 3

创建一个ArrayList<Details>() 并向其中添加详细信息。之后，返回此列表。

代码：

List<Details> detailsToReturn = new ArrayList<>();

for (Hashtable<String,String> result : handler.getResultSet()) {
            String baseId = result.get("baseId");
            ArrayList<Details> list = getHistoryDetails(baseId );

            for(Details t : list) {
                Details temp = new Details();
                temp.setStatus(t.getStatus();
                detailsToReturn.add(temp);
            }
        }

return detailsToReturn;

您提供的代码非常不清楚，所以如果这不是您想要的，我建议您为我们清除它。

Answer 4

您只创建 一个 Details 对象（实际上是两个，但第一个被丢弃了）。如果要保留从ArrayList 检索到的每个Details 对象，则需要在每次迭代for 循环时创建一个新的Details 对象。您还应该将这些添加到新的List。

当然，您只需将从getHistoryDetails() 获得的每个ArrayList 附加到一个新列表中，就可以节省大量工作。