I/O / Streams :: How To Iterate Over Files In A Directory One By One
Oct 5, 2014
Requirements - Use only standard Java API and no apache file utils for this.
Most of the answers I found on the internet either dont meet this requirement or load all file names into an array which can consume too much memory when no. of files = 20,000+. how I can do this. Is there also a way to keep track of new files that were added during the execution of the loop in this code ?
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Aug 1, 2007
In my program I have to get directory name&address, in this directory is none, one, or more *.txt(maybe not *.txt files) and I have to read info from all of them.
On C++ is very easy to do that with "findnext, find last, findfirst", so how can I do this in Java?
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Jan 8, 2015
ensureFileIsVisible not working.
JFileChooser fileChooser = new JFileChooser();
fileChooser.setCurrentDirectory(new File(currentDirectory));
File f = new File(currentDirectory);
ArrayList<String> names = new ArrayList<>(Arrays.asList(f.list()));
for (String s : names)
if (s.startsWith(yearofIssueTXT.getText())) {
fileChooser.setSelectedFile(new File(s));
fileChooser.ensureFileIsVisible(fileChooser.getSelectedFile());
break;
}
int result = fileChooser.showOpenDialog(addNewCoinBody);
The file is not visible because it is at almost the end of the files in the directory. I want the filechooser to automatically scroll so that the file is seen in the list.
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Apr 30, 2015
I've written a program to read files in a directory but I'd like for it to only read the text files of that directory.
import java.io.*;
public class Data {
public static void main(String[] args) throws IOException {
String target_dir = "C:files";
File dir = new File(target_dir);
File[] files = dir.listFiles();
[Code] .....
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Apr 23, 2015
I'm having another issue. I have 2 java source files(see below). They are place in the same directory. How do I compile them using classpath?
I have already tried 1st attempt :
javac -cp com.companyname.interview.DuplicateReplace.java DuplicateReplaceTest.java [did not work!]
2nd attempt: javac -cp DuplicateReplace.java DuplicateReplaceTest.java [again, did not work!]
package com.companyname.interview;
public class DuplicateReplace { /* code */}
[Code] ....
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Mar 31, 2015
Within tomcat "webapps" directory, have lots of scanned PDF files (size in KB and MB).Using Java and JSP, I want to search for any user entered text in these scanned PDF files.The result must display the name of those PDF files which has that entered text.
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Sep 18, 2014
If I specify the directory in file type or path string type how can I get a list of files that are file type .yml in that folder, so I can loop through and do something with each single file.yml in that specified directory.
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May 4, 2015
How can I Cache the data I'm reading from a collection of text files in a directory using a TreeMap? Currently my program reads the data from several text files in a directory and the saves that information in a text file called output.txt. I would like to cache this data in order to use it later. How can I do this using the TreeMap Class? These are the keys,values: TreeMap The data I'd like to Cache is (date from the file, time of the file, current time).
import java.io.*;
public class CacheData {
public static void main(String[] args) throws IOException {
String target_dir = "C:Files";
String output = "C:Filesoutput.txt";
File dir = new File(target_dir);
File[] files = dir.listFiles();
[Code] ....
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Jan 27, 2012
I have to be able to read files that have been serialized in VB. 2 things, 1 they are serialized in Binary, and I tried to look up on how to serialize/deserialize in Binary, but didn't have much support...
Also in the VB code they talk about "TYPES" which seems to be to just be a class full of stuff...
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May 24, 2014
I need to read the contents of file A, and B and store it in file C by joining the contents of A and B and also counting the number of letters/characters present in it.
I've come up with this so far.
import java.io.FileInputstream;
import java.io.FileNotFoundException;
import java.io.IOException;
public class JavaApplication43{
public static putwrite(string fname) throws FileNotFoundException, IOException
[code]...
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Jul 30, 2014
Program is to find the most frequently used words across all the input files, where each word must appear at least once in each file.
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May 22, 2014
My requirement is - I need to browse the folder and select multiples and upload all the selected files at once. note that here i need to use single browse button ONLY.
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Mar 12, 2014
this is the following task i am trying to do. Write an interface Directory to manipulate entries in a telephone directory for the University. The interface must support the following operations:
1) The ability to insert new entries into the directory. Entries should be stored in alphabetical order of surname.
2) Delete entries from the directory either by name or number
3) Provide a lookup method that will find the extension no of a member of staff given
his/her name. You should try to make this method run as efficiently as possible.
4) Change a person's telephone number
5) Print the telephone directory in a neatly tabulated fashion.
Write a class ArrayDirectory that implements this interface using an array to store the telephone directory information. The class must store the surname and initial for each member of staff and their telephone extension (a four digit number which may start with a zero). You may find it useful to define a class Entry to store information about individual entries. The entries should be read into the array from a text file consisting of multiple lines in the following format:
Surname<tab>Initials<tab>Telephone extension
The part that i am stuck on is trying to do the entry method, delete entries method, loop up method, change persons telephone number and be able to print it.
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May 26, 2014
Consider the url-pattern:
<url-pattern> /Beer/* </url-pattern>
The web app structure is: -
webapps
|
-->AdviceApp
|
-->WEB-INF
--> {{Beer}} This can be real or virtual.
My book says that /Beer/* can be a real or a virtual directory. What is the difference between the two and how do I create a virtual directory in tomcat ?
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Feb 27, 2015
I would like to know how I can iterate through objects . I have a manually created linked list (without using the built-in method one). So in the memory my object looks like this(attachment).I would like to do a for loop or while loop to get each element under the test3.head.
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Mar 25, 2015
List list1 = query1.list();
List list2 = query2.list();
for (Iterator itr = list1.iterator(); itr.hasNext();) {
Object[] row = (Object[]) itr.next();
}
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Mar 22, 2014
I've a contents in multimap like this,
key, value
{Name=[Amit, Akash, Amulya, Aparna, Angle],
Mail_Id=[amit@gmail.com, akash@gmail.com, amulya@gmail.com, aparna@gmail.com, angle@gmail.com]
Gender=[male, male, Female, female, female],
Age=[14, 15, 16, 17, 18]
}
Now, I want to display it like this,
Name = Amit
Mail_Id=amit@gmail.com
Gender=male
Age=14
Name = Akash
Mail_Id=akash@gmail.com
Gender=male
Age=15
Name = Amulya
Mail_Id= amulya@gmail.com
Gender=Female
Age=16
Name = Aparna
Mail_Id=aparna@gmail.com
Gender=Female
Age=17
Name = Angle
Mail_Id=angle@gmail.com
Gender=Female
Age=18
I mean, Each first element matches to first element of the next key. How to do this?
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Mar 10, 2014
I have an XML sheet and my project is top retrieve the required elements from XML sheet. So my format of XML was like follows:
<Class>
<Employees>
<EMPLOYEE>
<ENum> Abc123</ENum>
<Ename> John<?Ename>
<EType>Mathematics</EType>
[Code] ....
I have used unmarshalling concept to retrieve the data elements... I have to check whether the elements satisfy few regulations when compared with data in Database. So, i thought of grouping the employees depending on EType. I have created a Map with linkedlist of employees. Say Map<String, LinkedList<Employe>>EmpMap=new Map<String, LinkedList<Employe>>();
I have already created a class named Employee which has all the setter and getter methods for employee.
Here am going to take Etype(Employee type) as key and linkedlist(list of employees of certain type) as value. How to iterate these linked lists and place them in my Map.
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Mar 11, 2014
I facing issue with nested <c:forEach in my jsp page.I am using jstl.jar..Here is my code
in JAVA I have -->
List<ProductDefViewBean> productList = new ArrayList<ProductDefViewBean>();
productList.add(objProductDefViewBean);
request.setAttribute("ProductList", productList);
<%@ taglib uri="http://java.sun.com/jstl/core" prefix="c" %>
[code]...
javax.servlet.jsp.JspTagException: Don't know how to iterate over supplied "items" in <forEach>
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Aug 18, 2014
I have done this before in C++ but now I want to do it in Java. I am not sure how to iterate through a ArrayList, I have look several places because lets be honest the first stop is normally google. I tried the examples but with no luck.
for(auto it= foo.begin(); it!= foo.end(); foo++) {
*it //do something.
}
Here is the program:
package org.search.BFS;
import java.util.Queue;
public class BFS extends Graph {
private Queue<Integer> q;
BFS(int s) {
//mark all the vertices as not visited.
Also the below is giving me a Type safety: The expression of type ArrayList[] needs unchecked conversation to conform to ArrayList<Integer>[]
adj = new ArrayList[V];
What does this mean?
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Jan 22, 2015
first i looked at this example and understand this fine:
import java.util.ArrayList;
import java.util.Iterator;
public class Main {
[Code]....
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May 6, 2014
I have a JSP code which will open the contents of a excel file.
Now i need this contents of the excel file to be added dynamically to a table in the sameJSP. How to proceed.At the maximum 10 rows can be added dynamically.
Assuming i have a table in JSP which has heading first name,last name,DOB and Gender. After opening the excel through JSP the contents needs to be iterated and added to the columns mentioned.
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Sep 16, 2014
Is there anyway to iterate an enum type without an instance. As some context, consider the following code:
Java Code: public interface GenericChecker
{
public bool isValid(String str);
} mh_sh_highlight_all('java'); Java Code: public class EnumChecker<T extends Enum<T> > extends GenericChecker
{
private Class<T> enumType; //No instance
[code]....
toString method of the enum types has been overridden so that it returns the name assigned to the enum rather than the enum name itself. For example an enum might be SOME_ENUM("Assigned name"), therefore toString returns "Assigned name" rather than "SOME_ENUM". The idea is that a field from a table can be handed to the isValid(String) function on the GenericChecker base, and the derived class will then check to see if the field matches valid data as far as it is concerned.Thus, I can create a whole bunch of checkers easliy:
Java Code: GenericChecker checker1 = EnumChecker<EnumType1>();
GenericChecker checker2 = EnumChecker<EnumType2>();
GenericChecker checker3 = EnumChecker<EnumType3>();
GenericChecker checker4 = SomeOtherChecker(); mh_sh_highlight_all('java');
The problem is, if I use the EnumChecker then the expression "enumType.getEnumConstants()" in the isValid function blows up because enumType is null.
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Feb 9, 2014
I have an 46x9 array. I only have 108 values in the array for which I need to perform preliminary computations. How do I get the read to only read the 108 values whose values are greater than 0 and skip the other 495 whose values are 0?
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May 5, 2015
I am learning iterating through lists. What I have so far is two Hash Sets and two Tree sets. Hash Set 1 and Tree set 1 include the words from Roughing it by Mark Twain. Hash set 2 and tree set 2 include the words from Adventures of Huckleberry Finn by Mark Twain. (Everything is read from a file I made).
I am stuck trying to find out how to "Iterate through the words in HashSet1 and search for these words in both TreeSet2 and in HashSet2".Here is my code:
public class UsingSets {
public static void main(String[] args) throws FileNotFoundException {
String riHashIterator = null;
HashSet<String> riHash = new HashSet<>();
Scanner input = new Scanner(new File("roughingit.txt"));
while(input.hasNext()){
String riHashWords = input.next();
riHashWords = riHashWords.toLowerCase();
riHash.add(riHashWords);
[code]....
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Apr 20, 2014
my getDisplayValue() method. I am trying to iterate though an Array to display a value in a calculator, but I doesn't work. I keep on getting these weird magical numbers at the end of the iteration. Note that this is done in BlueJ.
Calculator -> UserInterface -> CalcEngine and Calculator -> CalcEngine.
public class CalcEngine
{
//Instance variables used.
//These are all the instance variables I used to implement
//a complete calculator solution.
[code]...
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