将txt文件转换为邻接列表，然后制作图

Question

我正在做一个宽度优先的搜索程序，它将读入邻接列表类型文本文件，然后相应地对其执行BFS。我无法在文本文件中读取，然后将其添加为节点的数组列表。

我该如何得到它来正确读取每一行并将它的连接关联起来？

我已经测试了我的程序，在我的main中手动添加节点，然后制作一个图形并在其上执行BFS。

这里是我的节点类：

import java.util.*; 

public class Node { 

     public String data; // data element 
     public boolean visited=false; // flag to track the already visited node 
     public List<Node> adjacentNodes = new LinkedList<Node>(); // adjacency list 
//  public List adjacentNodes = new LinkedList(); // adjacency list 
     public Node rootNode; 

     public Node(String data){ 
      this.data = data; 
     } 

     public void addAdjacentNode(final Node node){ 
      adjacentNodes.add(node); 
      node.adjacentNodes.add(this); 
//   adjacentNodes.add(rootNode); 
//   node.adjacentNodes.add(this) 
     } 

    } 

这里是我的Graph类：（当我试图在我的文本文件读取距离我的主）

import java.io.File; 
import java.io.FileNotFoundException; 
import java.io.InputStream; 
import java.util.*; 


/*- enqueue the start node to a Queue 
- make the start node as visited 
- while queue is not empty 
    - dequeue the node lets say u 
    - print or whatever you want to 
    - for every adjacent node v of u 
     - if v is not already visited 
      - mark v as visited 
      - enqueue v to the Queue*/ 
public class Graph { 

    public List nodes = new ArrayList(); 

    public void breadthFirstTraversal(Node rootNode){ 
     Queue<Node> q = new LinkedList<Node>(); 
//  Queue q = new LinkedList(); 
     q.add(rootNode); 
     System.out.print(rootNode.data + " "); 
//  printNode(rootNode); 
     rootNode.visited=true; 
     while(!q.isEmpty()){ 
      Node n = (Node)q.poll(); 
      System.out.print(n.data + " "); 
      for(Node adj : n.adjacentNodes){ 
       if(!adj.visited){ 
        adj.visited=true; 
        q.add(adj); 
       } 
      } 
      clearNodes(); 
     } 

    } 

    private void clearNodes() { 
     // TODO Auto-generated method stub 
     nodes = null; //clear nodes and set to null 
    } 

/* private void printNode(Node node) { 
     // TODO Auto-generated method stub 
     System.out.print(node); 
    }*/ 

    public static void main(String[] args) throws FileNotFoundException { 

     Graph g = new Graph(); 

     Scanner scan = new Scanner(new File("Connections.txt")); // scanner to read file 
     String line = scan.nextLine();      // read first line 
     int nbLine = Integer.parseInt(line);     // get number of lines 
     ArrayList<int[]> al = new ArrayList<int[]>();   
     for(int i = 0; i < nbLine; i++) {      // read each line 
      line = scan.nextLine(); 
      String[] token = line.split(" ");     // split each number into different String 
      int[] points = new int[token.length - 1];   // prepare array of int[] - 1 
//   int[] point = new int[]; 
      int[] point = new int[token.length]; 
     for(int j = 0; j < token.length; j++){    // skip first one 
      points[j-1] = Integer.parseInt(token[j]);  // store as int 
      al.add(points);         // save in ArrayList 
     } 


/*  Scanner s = new Scanner(new File("C:/Users/cantuj3/Documents/Ass 2/Connections.txt")); 
     ArrayList<Node> list = new ArrayList<Node>(); 
     while (s.hasNext()){ 
      g.nodes.add(s.next()); 
      //list.add(g); 
     }  
     s.close();*/ 



/*  Node frankfurt = new Node("frankfurt"); 
     Node mannheim = new Node("mannheim"); 
     Node wurzburg = new Node("wurzburg"); 
     Node stuttgard = new Node("stuttgard"); 
     Node kassel = new Node("kassel"); 
     Node karlsruhe = new Node("karlsruhe"); 
     Node erfurt = new Node("erfurt"); 
     Node numberg = new Node("numberg"); 
     Node augsburg = new Node("augsburg"); 
     Node munchen = new Node("munchen"); 

     Graph g = new Graph(); 

     g.nodes.add(frankfurt); 
     g.nodes.add(mannheim); 
     g.nodes.add(wurzburg); 
     g.nodes.add(stuttgard); 
     g.nodes.add(kassel); 
     g.nodes.add(karlsruhe); 
     g.nodes.add(erfurt); 
     g.nodes.add(numberg); 
     g.nodes.add(augsburg); 
     g.nodes.add(munchen); 

     frankfurt.addAdjacentNode(mannheim); 
     frankfurt.addAdjacentNode(wurzburg); 
     frankfurt.addAdjacentNode(kassel); 

     mannheim.addAdjacentNode(karlsruhe); 

     karlsruhe.addAdjacentNode(augsburg); 

     augsburg.addAdjacentNode(munchen); 

     munchen.addAdjacentNode(kassel); 
     munchen.addAdjacentNode(numberg); 

     wurzburg.addAdjacentNode(erfurt); 
     wurzburg.addAdjacentNode(numberg); 

     numberg.addAdjacentNode(stuttgard); 
     g.breadthFirstTraversal(frankfurt);*/ 
    } 

} 

这里是我的输入文件：

01 02 
02 01 03 
03 02 04 05 
04 03 
05 03 06 
06 05 

这里的代码块我在写我的主要通过自身：

 Scanner scan = new Scanner(new File("Connections.txt")); // scanner to read file 
     String line = scan.nextLine();      // read first line 
     int nbLine = Integer.parseInt(line);     // get number of lines 
     ArrayList<int[]> al = new ArrayList<int[]>();   
     for(int i = 0; i < nbLine; i++) {      // read each line 
      line = scan.nextLine(); 
      String[] token = line.split(" ");     // split each number into different String 
      int[] points = new int[token.length - 1];   // prepare array of int[] - 1 
//   int[] point = new int[]; 
      int[] point; 
     for(int j = 0; j < token.length; j++){    // skip first one 
      points[j-1] = Integer.parseInt(token[j]);  // store as int 
      al.add(points);         // save in ArrayList 
     } 

上午我在正确的轨道？

Answer 1

你的基本步骤将需要：

1. 读取一行文件
2. 把那行成一个对象
3. 这个对象添加到集合
4. 重复，直到你有没有更多的线

因为我不想为你做你的工作，我会给你留下一些样品：

读取一行文件

String line = reader.readLine(); // in this case, 'reader' will be a BufferedReader referencing your file 

把那行成一个对象

这取决于你的输入文件的格式是什么样子。举个例子，如果我的输入是这样的：

first_thing 10 
second_thing 20 
third_thing 30 
... 

话，我可以这样做：

String[] components = line.split(" "); 
if (components.length == 2) { 
    MyCustomObject myCustomObject = new MyCustomObject(components[0], components[1]); 
} 

这个对象添加到集合

String[] components = line.split(" "); 
if (components.length == 2) { 
    MyCustomObject myCustomObject = new MyCustomObject(components[0], components[1]); 
    myCollection.add(myCustomObject); // you can choose the type of collection here 
} 

重复，直到你没有更多的行

while ((line = reader.readLine()) != null) { 
    ... 
} 

希望这会有所帮助！