Sorting 树集实现？

我试图实现一个树集而不是ArrayList，因为我需要对该列表进行排序。原代码为：

private final List<Report> reports = new ArrayList<Report>();
public void receiveReport(final Report report) {
        this.reports.add(report);
    }

这是报告文件： 包装dsa.speedcamera

public class Report {
    public TimeID timeID;
    public int speedLimit;
    public String carRegistration;
    public int speedRecorded;
    /** 
     * Returns a String representing the values in this object so that is can
     * be directly printed with System.out.println();
     */
    public String toString() {
        return timeID.toString() +  
        "\nSpeed limit: " + speedLimit + " mph" +
        "\nCar registration: " + carRegistration +
        "\nSpeed recorded: " + speedRecorded + " mph";
    }
}

---

该怎么办？

对于用户定义的对象，不能直接添加到树集。您需要给TreeSet一个属性，排序应该适用于该属性。例如，您是基于

速度限制

还是

速度记录

进行排序？我怎么知道？TreeSet怎么知道

为了给TreeSet提供这些信息，您需要提供我们称之为定制比较器的东西

请通读下面的文章，它们会帮助你的

---

报表

是一个类，该类中必须有一些属性（整数、字符串），排序应适用于这些属性。您需要将该信息提供给TreeSet，对吗？@Sim Sam我编辑了它，现在您可以看到report类了

Exception in thread "main" java.lang.ClassCastException: class dsa.speedcamera.Report cannot be cast to class java.lang.Comparable (dsa.speedcamera.Report is in unnamed module of loader 'app'; 
java.lang.Comparable is in module java.base of loader 'bootstrap')
    at java.base/java.util.TreeMap.compare(TreeMap.java:1563)
    at java.base/java.util.TreeMap.addEntryToEmptyMap(TreeMap.java:768)
    at java.base/java.util.TreeMap.put(TreeMap.java:777)
    at java.base/java.util.TreeMap.put(TreeMap.java:534)
    at java.base/java.util.TreeSet.add(TreeSet.java:255)
    at dsa.speedcamera.ProvidedImplementation.receiveReport(ProvidedImplementation.java:19)
    at dsa.speedcamera.ProvidedImplementation.demonstration(ProvidedImplementation.java:73)
    at dsa.speedcamera.ProvidedImplementation.main(ProvidedImplementation.java:92)

Process finished with exit code 1

public class Report {
    public TimeID timeID;
    public int speedLimit;
    public String carRegistration;
    public int speedRecorded;
    /** 
     * Returns a String representing the values in this object so that is can
     * be directly printed with System.out.println();
     */
    public String toString() {
        return timeID.toString() +  
        "\nSpeed limit: " + speedLimit + " mph" +
        "\nCar registration: " + carRegistration +
        "\nSpeed recorded: " + speedRecorded + " mph";
    }
}