Java树从路径列表中表示文件系统（files / dir） [英] Java Tree to represent filesystem (files/dir) from list of paths

问题描述

我有这样的路径列表

/mnt/sdcard/folder1/a/b/file1
/mnt/sdcard/folder1/a/b/file2
/mnt/sdcard/folder1/a/b/file3
/mnt/sdcard/folder1/a/b/file4
/mnt/sdcard/folder1/a/b/file5
/mnt/sdcard/folder1/e/c/file6
/mnt/sdcard/folder2/d/file7
/mnt/sdcard/folder2/d/file8
/mnt/sdcard/file9

所以从这个列表路径（Stings）我需要克隆一个Java树结构，它具有文件夹作为节点和文件作为叶（不会有空的文件夹作为叶）。

So from this list of paths (Stings) I need to crete a Java Tree structure that has folders as nodes and files as leaf (there wont be empty folders as leaf).

我需要什么认为是添加方法，我将它传递给一个String（文件的路径），并将其添加到树中正确的位置，创建正确的节点（Folder）（如果它们还没有存在）

What I need I think is the add method where I pass to them a String (path of the file) and it add it to the correct place in the tree creating correct nodes (Folder) if they are not already there

当我在节点和树叶列表时，这个树结构将需要我获取节点列表（但我认为这将是树的正常特征）

This tree structure will need me to get list of nodes when I'm on node and list of leafs (but I think this will be a normal features for trees)

我将始终将字符串作为路径，而不是真正的文件o r文件夹。
有什么可以使用或源代码开始吗？

I will always have Strings as paths and not real file or folders. Is there something ready to use or a source code to start?

非常感谢。

推荐答案

谢谢你的回答。我做了我的工作实现。
我想我将需要改进它，以使它更好的工作，更多的缓存添加元素到树结构。

Thank you for all your answer. I made my working implementation. I think that I will need to improve it in order to make it works better with more caching in adding element to the tree structure.

正如我所说我需要的是一个结构，允许我有一个虚拟表示FS。

As I said what I was needing was a structure that allow me to have a "virtual" rappresentation of a FS.

MXMTree.java

MXMTree.java

public class MXMTree {

    MXMNode root;
    MXMNode commonRoot;

    public MXMTree( MXMNode root ) {
        this.root = root;
        commonRoot = null;
    }

    public void addElement( String elementValue ) { 
        String[] list = elementValue.split("/");

        // latest element of the list is the filename.extrension
        root.addElement(root.incrementalPath, list);

    }

    public void printTree() {
        //I move the tree common root to the current common root because I don't mind about initial folder
        //that has only 1 child (and no leaf)
        getCommonRoot();
        commonRoot.printNode(0);
    }

    public MXMNode getCommonRoot() {
        if ( commonRoot != null)
            return commonRoot;
        else {
            MXMNode current = root;
            while ( current.leafs.size() <= 0 ) {
                current = current.childs.get(0);
            }
            commonRoot = current;
            return commonRoot;
        }

    }


}

MXMNode.java

MXMNode.java

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;


public class MXMNode {

    List<MXMNode> childs;
    List<MXMNode> leafs;
    String data;
    String incrementalPath;

    public MXMNode( String nodeValue, String incrementalPath ) {
        childs = new ArrayList<MXMNode>();
        leafs = new ArrayList<MXMNode>();
        data = nodeValue;
        this. incrementalPath = incrementalPath;
    }

    public boolean isLeaf() {
        return childs.isEmpty() && leafs.isEmpty();
    }

    public void addElement(String currentPath, String[] list) {

        //Avoid first element that can be an empty string if you split a string that has a starting slash as /sd/card/
        while( list[0] == null || list[0].equals("") )
            list = Arrays.copyOfRange(list, 1, list.length);

        MXMNode currentChild = new MXMNode(list[0], currentPath+"/"+list[0]);
        if ( list.length == 1 ) {
            leafs.add( currentChild );
            return;
        } else {
            int index = childs.indexOf( currentChild );
            if ( index == -1 ) {
                childs.add( currentChild );
                currentChild.addElement(currentChild.incrementalPath, Arrays.copyOfRange(list, 1, list.length));
            } else {
                MXMNode nextChild = childs.get(index);
                nextChild.addElement(currentChild.incrementalPath, Arrays.copyOfRange(list, 1, list.length));
            }
        }
    }

    @Override
    public boolean equals(Object obj) {
        MXMNode cmpObj = (MXMNode)obj;
        return incrementalPath.equals( cmpObj.incrementalPath ) && data.equals( cmpObj.data );
    }

    public void printNode( int increment ) {
        for (int i = 0; i < increment; i++) {
            System.out.print(" ");
        }
        System.out.println(incrementalPath + (isLeaf() ? " -> " + data : "")  );
        for( MXMNode n: childs)
            n.printNode(increment+2);
        for( MXMNode n: leafs)
            n.printNode(increment+2);
    }

    @Override
    public String toString() {
        return data;
    }


}

Test.java测试代码

Test.java for test code

public class Test {

    /**
     * @param args
     */
    public static void main(String[] args) {

        String slist[] = new String[] { 
                "/mnt/sdcard/folder1/a/b/file1.file", 
                "/mnt/sdcard/folder1/a/b/file2.file", 
                "/mnt/sdcard/folder1/a/b/file3.file", 
                "/mnt/sdcard/folder1/a/b/file4.file",
                "/mnt/sdcard/folder1/a/b/file5.file", 
                "/mnt/sdcard/folder1/e/c/file6.file", 
                "/mnt/sdcard/folder2/d/file7.file", 
                "/mnt/sdcard/folder2/d/file8.file", 
                "/mnt/sdcard/file9.file" 
        };

        MXMTree tree = new MXMTree(new MXMNode("root", "root"));
        for (String data : slist) {
            tree.addElement(data);
        }

        tree.printTree();
    }

}

请告诉我，如果你有关于改进的好建议：）

Please tell me if you have some good advice about improvments :)

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