在 Java 中扫描文件输入到 HashMap 中
因此,我尝试遍历一个目录并查找名为“rels.txt”的文件的所有实例,对于每个实例,我想进入该文件并将文件中的各个值加载到 Java 中的 HashMap 中。下面是我正在使用的“rels.txt”文件之一的内容:
文本文件:
rId8,image2
rId13,image5
rId7,image1
rId12,image4
rId17,image8
rId15,image7
rId9,image3
rId14,image6
这是我迄今为止的 Java 代码,它应该遍历目录并存储每个HashMap 中的值,打印出 HashMap,然后清除它(以便可以从目录中的另一个“rels.txt”文件存储一组新值)。
Java 代码:
private void traverse(File directory) throws FileNotFoundException
{
//Get all files in directory
File[] files = directory.listFiles();
for (File file : files)
{
if (file.getName().equals("rels.txt"))
{
Scanner scan = new Scanner(file).useDelimiter(",");
while (scan.hasNextLine())
{
String id;
String image;
id = scan.next();
image = scan.next();
imageMap.put(id, image);
}
System.out.println(imageMap);
imageMap.clear();
}
else if (file.isDirectory())
{
//It's a directory so (recursively) traverse it
traverse(file);
}
}
}
这是我收到的错误/输出,我不太确定哪里出了问题。
错误/输出
Exception in thread "main" java.util.NoSuchElementException
at java.util.Scanner.throwFor(Unknown Source)
at java.util.Scanner.next(Unknown Source)
at XMLTagParser.traverse(XMLTagParser.java:153)
at XMLTagParser.traverse(XMLTagParser.java:198)
at XMLTagParser.traverse(XMLTagParser.java:198)
at XMLTagParser.<init>(XMLTagParser.java:27)
at IPDriver.main(IPDriver.java:21)
{image26
rId19=image9
rId31, image15
rId33=image23
rId38, image29
rId21=image11
rId34, image12
rId27=image17
rId30, image28
rId16=image6
rId20, image14
rId32=image22
rId37, image2
rId17=image7
rId25, rId13=image3
rId18, image20
rId35=image25
, image8
rId26=image16
rId39, image24
rId7=image1
rId12, image21
rId14=image4
rId22, image10
rId29=image19
rId24, image13
rId28=image18
rId36, image27
rId15=image5
rId23}
通过这段代码,我本质上只是希望能够为项目的另一部分调用 HashMap,并且当我引用其中一个 rId 值时,我可以获得相应的图像值。有谁知道我可能做错了什么,或者甚至有更有效的解决方案?提前致谢。
工作 Java 代码感谢 Friedrik:
private void traverse(File directory) throws FileNotFoundException
{
//Get all files in directory
File[] files = directory.listFiles();
for (File file : files)
{
if (file.getName().equals("rels.txt"))
{
Scanner scan = new Scanner(file);
while (scan.hasNextLine())
{
String[] line = scan.nextLine().split(",");
imageMap.put(line[0], line[1]);
}
System.out.println(imageMap);
imageMap.clear();
}
else if (file.isDirectory())
{
//It's a directory so (recursively) traverse it
traverse(file);
}
}
}
So I am trying to traverse a directory and find all the instances of a file called "rels.txt", and for each instance, I want to go into the file and load up the individual values from the file into a HashMap in Java. Below are the contents of one of the "rels.txt" files I am working with:
Text File:
rId8,image2
rId13,image5
rId7,image1
rId12,image4
rId17,image8
rId15,image7
rId9,image3
rId14,image6
Here is the Java code I have thus far that is supposed to traverse the directory and store each of the values in the HashMap, print out the HashMap, then clear it (so that a new set of values can be stored from another "rels.txt" file within the directory).
Java Code:
private void traverse(File directory) throws FileNotFoundException
{
//Get all files in directory
File[] files = directory.listFiles();
for (File file : files)
{
if (file.getName().equals("rels.txt"))
{
Scanner scan = new Scanner(file).useDelimiter(",");
while (scan.hasNextLine())
{
String id;
String image;
id = scan.next();
image = scan.next();
imageMap.put(id, image);
}
System.out.println(imageMap);
imageMap.clear();
}
else if (file.isDirectory())
{
//It's a directory so (recursively) traverse it
traverse(file);
}
}
}
This is the error/output I am getting and I am not quite sure where I am going wrong.
Error/Output
Exception in thread "main" java.util.NoSuchElementException
at java.util.Scanner.throwFor(Unknown Source)
at java.util.Scanner.next(Unknown Source)
at XMLTagParser.traverse(XMLTagParser.java:153)
at XMLTagParser.traverse(XMLTagParser.java:198)
at XMLTagParser.traverse(XMLTagParser.java:198)
at XMLTagParser.<init>(XMLTagParser.java:27)
at IPDriver.main(IPDriver.java:21)
{image26
rId19=image9
rId31, image15
rId33=image23
rId38, image29
rId21=image11
rId34, image12
rId27=image17
rId30, image28
rId16=image6
rId20, image14
rId32=image22
rId37, image2
rId17=image7
rId25, rId13=image3
rId18, image20
rId35=image25
, image8
rId26=image16
rId39, image24
rId7=image1
rId12, image21
rId14=image4
rId22, image10
rId29=image19
rId24, image13
rId28=image18
rId36, image27
rId15=image5
rId23}
With this code, I essentially just want to be able to call the HashMap for another part of my project and when I reference one of the rId values, I can get the corresponding image value. Does anyone have any ideas as to what I may be doing wrong or maybe even a more efficient solution? Thanks in advance.
Working Java Code Thanks to Friedrik:
private void traverse(File directory) throws FileNotFoundException
{
//Get all files in directory
File[] files = directory.listFiles();
for (File file : files)
{
if (file.getName().equals("rels.txt"))
{
Scanner scan = new Scanner(file);
while (scan.hasNextLine())
{
String[] line = scan.nextLine().split(",");
imageMap.put(line[0], line[1]);
}
System.out.println(imageMap);
imageMap.clear();
}
else if (file.isDirectory())
{
//It's a directory so (recursively) traverse it
traverse(file);
}
}
}
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由于分隔符是“,”,scan.next() 一起读取“image2\nrId13”。它将返回视为一个字符,而不是分隔符。
另一种方法是删除扫描仪的“useDelimiter(”,”)”并使用此循环:
只需确保您的文件不会以返回结束。
Since the delimiter is "," scan.next() reads "image2\nrId13" together. It considers the return as a character, not a delimiter.
Another way to do this, delete the "useDelimiter(",")" of the Scanner and use this loop :
just make sure that your file doesn't end by a return.
假设您的文件正是您所说的,您可以尝试将
hasNextLine
更改为hasNext
Assuming your file is exactly what you said, you can try changing the
hasNextLine
tohasNext