Android，帮助解决 simpleframework PersistenceException

Question

我正在尝试使用org.simpleframework.xml。在我的 Android 项目中处理 xml 数据的类。我无法理解如何构建我的类“Point”构造函数以匹配 xml 定义：在运行时我收到此异常：

org.simpleframework.xml.core.PersistenceException: Constructor not matched for class koine.marcos.wifidemo.Point

我的 xml 数据如下所示：

---

文件points.xml：

<?xml version="1.0" encoding="utf-8"?>
<points>
   <point id="La Gioconda">
      <rssi ssid="beacon1" bssid="00:21:91:d1:36:62">-52</rssi>
      <rssi ssid="beacon2" bssid="00:12:a9:03:23:32">-97</rssi>
   </point>
   <point id="La Pietà">
      <rssi ssid="beacon1" bssid="00:21:91:d1:36:62">-68</rssi>
      <rssi ssid="beacon2" bssid="00:12:a9:03:23:32">-83</rssi>
   </point>
</points>

---

文件Rssi.java：

@Root
public class Rssi {

    @Attribute(required=false)
    protected String id;

    @Element(required=false)
    protected Integer value;

    ... getters and setters ...
}

---

文件point.java :

@Root
public class Point {
    @Attribute
    protected String id;

    @ElementMap(entry="rssi", key="id", attribute=false,
                inline=true, required=false)
    private Map<String,Integer> rssiMap;

    public Point(String id, Map<String,Integer>rssi) {
        this.id = id;
        ...
    }

    ...
}

---

文件点:java:

@Element
public class Points {
    @ElementList(inline=true, required=true)
    private List<Point> list;

    ... getters and setters ...
}

Answer 1

好的，因为我一直是 坚定地宣扬 Simple XML 到底有多棒 我想我会给您这个问题的完整答案，所以就在这里。完整的工作代码。

Points.java

// You can make this non private and more complex at will.
public class Points {
    @ElementList(entry = "point", inline = true) public ArrayList<Point> points;
}

Point.java

public class Point {
    private final String id;
    private final HashMap<String, Integer> rssiMap;

    public Point(@Attribute(name = "id") String id, @ElementMap(attribute = true, entry = "rssi", key = "ssid", valueType = Integer.class, inline = true) HashMap<String, Integer> rssiMap) {
        this.id = id;
        this.rssiMap = rssiMap;
    }

    @Attribute(name = "id") 
    public String getId() {
            return id;
    }

    @ElementMap(attribute = true, entry = "rssi", key = "ssid", valueType = Integer.class, inline = true)
    public HashMap<String, Integer> getRssi() {
            return rssiMap;
    }
}

Main.java

public class Main {
    public static void main(String[] args) throws Exception {
        Serializer serial = new Persister();

        // Warning: You will need to make sure that this file exists or change it.
        File file = new File("data/data.xml");
        Points points = serial.read(Points.class, file);
        for(Point point : points.points) {
            System.out.println(point.getId());
            for(Entry<String, Integer> entry : point.getRssi().entrySet()) {
                System.out.println(" " + entry.getKey() + ": " + entry.getValue());
            }
        }
    }
}

这就是它的全部内容。它应该很容易读取您的数据。如果您要尝试该代码，那么您必须确保的唯一一件事是 Main 函数正确设置您要读取的文件，或者您只需为读取函数提供正确的输入。

PS 我已经在我的电脑上测试过这个，所以我知道它有效。干杯。