带有索引，键和值的Java Collection

My question might sound silly, but would like to know whether there are any Collection object in Java that does store index,key and values in a single Collection object?

我的问题可能听起来很愚蠢，但是想知道Java中是否有任何Collection对象在单个Collection对象中存储索引，键和值？

I have the following:

我有以下内容：

Enumeration hs = request.getParameterNames();
LinkedHashMap<String, String> linkedHashMap = new LinkedHashMap<String, String>();
while (hs.hasMoreElements()) {
    linkedHashMap.put(value, request.getParameter(value));
}

The above stores key and value in linkedHashMap, but it doesn't have an index. If it has then I could call by index(pos) and get corresponding key and value.

以上内容在linkedHashMap中存储键和值，但它没有索引。如果它有，那么我可以通过索引（pos）调用并获得相应的键和值。

Edit 1

编辑1

I would want to conditionally check if index(position) is x then get the corresponding key and value pair and construct a string with query.

我想条件检查索引（位置）是否为x然后获取相应的键和值对并构造一个带查询的字符串。

3 个解决方案

#1

As mentioned by others, Java collections does not support this. A workaround is Map<R, Map<C, V>>. But it is too ugly to use. You can go with Guava. It provides a Table collection type. It has the following format Table<R, C, V>. I haven't tried this but I think this will work for you.

正如其他人所提到的，Java集合不支持这一点。解决方法是Map >。但它太难看了。你可以和番石榴一起去。它提供了表集合类型。它具有以下格式表。我没试过，但我认为这对你有用。，c，v> ，map>

Enumeration hs = request.getParameterNames();
Table<Integer, String, String> table = HashBasedTable.create();
while (hs.hasMoreElements()) {
    table.put(index, value, request.getParameter(value));
}

Now, if you want key, value pair at, let's say, index 1. Just do table.row(1). Similarly, to get index, value pairs just do table.column(value).

现在，如果你想要键，值对，比方说，索引1.只需要做table.row（1）。同样，要获取索引，值对只需执行table.column（value）。

#2

No Collection in java, will support this. You need to create a new class IndexedMap inheriting HashMap and store the key object into the arraylist by overriding put method.

在java中没有Collection，会支持这个。您需要创建一个继承HashMap的新类IndexedMap，并通过重写put方法将键对象存储到arraylist中。

here is the answer(answerd by another user: Adriaan Koster)

这是答案（另一位用户回答：Adriaan Koster）

how to get the one entry from hashmap without iterating

如何从hashmap中获取一个条目而不进行迭代

#3

Maybe you need implementing yourself for achieving this functionality.

也许你需要实现自己来实现这个功能。

public class Param{
    private String key;
    private String value;
    public Param(String key, String value){
        this.key = key;
        this.value = value;
    }
    public void setKey(String key){
        this.key = key;
    }
    public String getKey(){
        return this.key;
    }

    public void setValue(String value){
        this.value = value;
    }
    public String getValue(){
        return this.value;
    }
}

Enumeration hs = request.getParameterNames();
List<Param> list = new ArrayList<Param>();
while (hs.hasMoreElements()) {
    String key = hs.nextElement();
    list.add(new Param(key, request.getParameter(key)));
}

By doing this, you could get param with an index provided by List API.

通过这样做，您可以获得由List API提供的索引的参数。

#1

Enumeration hs = request.getParameterNames();
Table<Integer, String, String> table = HashBasedTable.create();
while (hs.hasMoreElements()) {
    table.put(index, value, request.getParameter(value));
}