All header files in java

Best way to insert headers while writing file in java

Question: I have created the file header after adding around 30-40 java classes and interfaces , is there any method to include that header tag to all the files which have already created on intelliJIdea , Header tags are being included to all the files which create after defining the header tags on the setting , but how to add them to old files ? Question: I have scenario where i have to insert header manually which looks like below Header: I have achieved this by string concatenation like sample below:

Best way to insert headers while writing file in java

I have scenario where i have to insert header manually which looks like below

I have achieved this by string concatenation like sample below:

Note: I have more than 10 imports.This is just sample.

since the text is more and requires also proper alignment(like each import on next line and also escape «») when i am inserting header into other file, I want to know if there are any alternatives to do this in efficient way in java.

I assume this is a JSP Question

If it is, then use a static include (A static include is resolved at compile time)

or for for dynamic inclusion:

Java — Compare file extension to file header, For other types with no significant header you can implement completly other type checks. You can extract the mime type for each file and compare this to a map of mimetype/extension ( Map>, the first String is the mime type, the second is a list of valid extensions).

How to read csv file by using headers using java?

I have a csv file which contains 5 header fields like field1,field2,field3,field4,field5. The file contains data for this headers for different users. Some columns may contains null values as only three columns are compulsary.

I want to read columns by specifying its header, something like if I specified field1 and field3 then read values of these columns only.

I tried opencsv to do that and readAll Function of opencsv. I also tried CSVReader.

public void startScanFile()< String mydemofile=pathtofile; BufferedReader br =null; try < System.out.println("\nEnter the column number that contains ip : "); br = new BufferedReader(new InputStreamReader(System.in)); ipcolumn = Integer.parseInt(br.readLine()); System.out.println("\nEnter the column number that contains username : "); br = new BufferedReader(new InputStreamReader(System.in)); usercolumn = Integer.parseInt(br.readLine()); System.out.println("\n Enter the column number that contains password"); br = new BufferedReader(new InputStreamReader(System.in)); passcolumn = Integer.parseInt(br.readLine()); >catch(Exception e) < >try < CSVReader csvReader = new CSVReader(new FileReader(mydemofile)); String[] row; while ((row = csvReader.readNext())!=null)< System.out.println("Col1 is is : " + row[1]); System.out.println("Col3 is : " + row[3]); System.out.println("Col4 is : " + row[4]); >> catch (FileNotFoundException e) < // TODO Auto-generated catch block e.printStackTrace(); >catch (IOException e) < // TODO Auto-generated catch block e.printStackTrace(); >

How can I read values of specified headers only?

Try Apache Commons CSV or OpenCSV.

If you using csvreader you can use this

I can suggest the following csv library. Its good. Check the below url which contains the example how to get the csv data using header and you can also validate the data.

http://supercsv.sourceforge.net/examples_reading.html 

How to include Header File (.h) in Java, The .h files are C language include files which usually describe the methods and data structures of a C-library. You would have to Java Native Interface (JNI) in order to include these libraries in your java code. You have basically two options. Go through a tutorial like this. Or look for a java implementation. …

Can someone explain .wav(WAVE) file headers?

OK, so I’m trying to make a program that will manipulate .wav files, and I’ve seen this question/answers, but I’m not entirely sure as to what each piece of data in the header refers to. For example, what does a «chunk» refer to? Is that a specific number of bits/bytes?

If somebody could just tell me, at least in the format used in this question, what each datum being written to the .wav, aside from the constant String Literals and the ‘data’ array, refer to? In particular I’d especially like to know what a «chunk» is, and how Sample Rate, Byte Rate, Bytes per Sample, and Bytes per Sample for all Channels relate?(I suspect Byte Rate is Sample Rate * Bytes per Sample, but what about the ‘for all channels’ one?)

It is against the board rules to just post a link, so here is the table I took from http://www.topherlee.com/software/pcm-tut-wavformat.html

Positions Sample Value Description 1 - 4 "RIFF" Marks the file as a riff file. Characters are each 1. byte long. 5 - 8 File size (integer) Size of the overall file - 8 bytes, in bytes (32-bit integer). Typically, you'd fill this in after creation. 9 -12 "WAVE" File Type Header. For our purposes, it always equals "WAVE". 13-16 "fmt " Format chunk marker. Includes trailing null 17-20 16 Length of format data as listed above 21-22 1 Type of format (1 is PCM) - 2 byte integer 23-24 2 Number of Channels - 2 byte integer 25-28 44100 Sample Rate - 32 bit integer. Common values are 44100 (CD), 48000 (DAT). Sample Rate = Number of Samples per second, or Hertz. 29-32 176400 (Sample Rate * BitsPerSample * Channels) / 8. 33-34 4 (BitsPerSample * Channels) / 8.1 - 8 bit mono2 - 8 bit stereo/16 bit mono4 - 16 bit stereo 35-36 16 Bits per sample 37-40 "data" "data" chunk header. Marks the beginning of the data section. 41-44 File size (data) Size of the data section, i.e. file size - 44 bytes header. 

Sample values are given above for a 16-bit stereo source.

Update/Reminder

The header integers are all in Least significant byte order, so the two byte channel information 0x01 0x00 are actually 0x00001 e.g. mono.

I know OP tagged the question as Java, but here’s complete Kotlin code for reading the header that could pass for Java. Reading Little Endian could be tricky, but thankfully we don’t have to do that.

class WaveHeader(bytes: ByteArray) < init < require(bytes.size >= SIZE) < "Input size is must be at least $SIZE bytes" >> private var start = 0 private val riff = RiffChunk( String(bytes.copyOfRange(start, start + 4)) .also < require(it == "RIFF") < "$it must be 'RIFF'" >start += it.length >, ByteBuffer.wrap(bytes.copyOfRange(start, start + 4)).order(ByteOrder.LITTLE_ENDIAN) .also < start += it.capacity() >.int, String(bytes.copyOfRange(start, start + 4)) .also < require(it == "WAVE") < "$it must be 'WAVE'" >start += it.length > ) private val format = FormatChunk( // null terminated String(bytes.copyOfRange(start, start + 3)) .also < require(it == "fmt") < "$it must be 'fmt'" >start += 4 >, ByteBuffer.wrap(bytes.copyOfRange(start, start + 4)).order(ByteOrder.LITTLE_ENDIAN) .also < start += it.capacity() >.int, ByteBuffer.wrap(bytes.copyOfRange(start, start + 2)).order(ByteOrder.LITTLE_ENDIAN) .also < start += it.capacity() >.let < if (it.short == 1.toShort()) "PCM" else "OTHER ($)" >, ByteBuffer.wrap(bytes.copyOfRange(start, start + 2)).order(ByteOrder.LITTLE_ENDIAN) .also < start += it.capacity() >.short, ByteBuffer.wrap(bytes.copyOfRange(start, start + 4)).order(ByteOrder.LITTLE_ENDIAN) .also < start += it.capacity() >.int, ByteBuffer.wrap(bytes.copyOfRange(start, start + 4)).order(ByteOrder.LITTLE_ENDIAN) .also < start += it.capacity() >.int, ByteBuffer.wrap(bytes.copyOfRange(start, start + 2)).order(ByteOrder.LITTLE_ENDIAN) .also < start += it.capacity() >.short, ByteBuffer.wrap(bytes.copyOfRange(start, start + 2)).order(ByteOrder.LITTLE_ENDIAN) .also < start += it.capacity() >.short ) private val `data` = DataChunk( String(bytes.copyOfRange(start, start + 4)) // remove all null chars .replace("\u0000", "") .also < start += it.length >, ByteBuffer.wrap(bytes.copyOfRange(start, start + 4)).order(ByteOrder.LITTLE_ENDIAN) .also < start += it.capacity() >.int ) init < assert(start == 44) < "Illegal state" >> data class RiffChunk(val id: String, val size: Int, val format: String) data class FormatChunk( val id: String, val size: Int, val format: String, val numChannels: Short, val sampleRate: Int, val byteRate: Int, val blockAlign: Short, val bitsPerSample: Short ) data class DataChunk(val id: String, val size: Int) override fun toString(): String < val ls = System.lineSeparator() return "WaveHeader($ls\t$riff>$ls\t$format$ls\t$`data`$ls)" > companion object < const val SIZE = 44 fun fromPath(path: String): WaveHeader = fromInputStream(WaveHeader::class.java.getResourceAsStream(path)) fun fromUrl(url: String): WaveHeader = fromInputStream(URL(url).openStream()) private fun fromInputStream(input: InputStream): WaveHeader < val bytes = input.use < it.readNBytes(SIZE) >return WaveHeader(bytes) > > > fun main(args: Array) < if (args.isEmpty()) < System.err.println("Argument is missing") >println(WaveHeader.fromUrl(args[0])) > 

Running with this URL produces the output:

WaveHeader( RiffChunk(id=RIFF, size=168050, format=WAVE)> FormatChunk(id=fmt, size=18, format=PCM, numChannels=1, sampleRate=16000, byteRate=32000, blockAlign=2, bitsPerSample=16) DataChunk(id=fa, size=1952670054) ) 

Java File Class, Java File Class. The File class is an abstract representation of file and directory pathname. A pathname can be either absolute or relative. The File class have several methods for working with directories and files such as creating new directories or files, deleting and renaming directories or files, listing the contents …

How to include file header to all the java classes and interfaces which has already created in IntelliJIdea

I have created the file header after adding around 30-40 java classes and interfaces , is there any method to include that header tag to all the files which have already created on intelliJIdea , Header tags are being included to all the files which create after defining the header tags on the setting , but how to add them to old files ?

There two different kinds of file header and it’s not clear which way you chose.

1. File and code templates

The header file template cannot be applied after file creation, bc the template defines the complete file. IntelliJ cannot simply defect the what to change after the file has been created.

If you used this feature to customize your files, I would suggest, that you use the search and replace with regular expression feature.

2. Copyright

The purpose of this feature is to provide every file with a copyright/license header.

The Copyright file header can be adjusted after files have bean created. Follow the instructions and use the update copyright feature.

Furthermore, IntelliJ has a feature called update copyright that allows you to define a regex to detect copyrights in comments. That enables InelliJ to detect a copyright — or file header in your situation — to apply changes after files have been created.

How to read csv file by using headers using java?, The file contains data for this headers for different users. Some columns may contains null values as only three columns are compulsary. I want to read columns by specifying its header, something like if I specified field1 and field3 then read values of these columns only. I tried opencsv to do that and readAll …

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What are the Java header files?

The header file provides a C function signature for the implementation of the native method displayHelloWorld defined in that class. Run javah now on the HelloWorld class that you created in the previous steps. The name of the header file is the Java class name with a . h appended to the end.

How do you add a header in Java?

You can’t include a C header file in Java. you cannot do it directly in java. You have to include the header files in your C program and use JNI to call the functions that you want to use. To run native code from Java, you need using JNI technology.

How do I view a header file?

How do I open an H file? Since header files are plain text files, you can open and view the file contents in a text editor. However, it’s easier to edit *. h files and other source code files using a code editor like Microsoft Visual Studio or Apple Xcode.

What is a class header in Java?

Here is a breakdown of the source code representation of a Java class. A class can be broken down into two things: The first piece is a class-header which consists of the keyword ” class ” and the name you give to the class. Names in programming languages are also known as identifiers. The second piece is the body.

Do you need a header file in Java?

Source code written in Java is simple. There is no preprocessor, no #define and related capabilities, no typedef, and absent those features, no longer any need for header files. Instead of header files, Java language source files provide the declarations of other classes and their methods.

How to get the value of a header in Java?

Since: 1.6 1 getFirst (String) returns a single valued header or the first value of a multi-valued header. 2 add (String,String) adds the given header value to the list for the given key 3 set (String,String) sets the given header field to the single value given overwriting any existing values in the value list.

Which is header file is used in pacakages Java program?

Java does not require header files like C/C++. Which header file is used in pacakages java program? Java doesn’t use header files. Is header files in c are similar to packages in java? No. Why doesn’t Java use header files? A header file in C is used to import the features of parent classes in our class.

Which is an example of a header file in C?

Header files include data types definitions, function prototypes, and C preprocessor commands. For example, we use function printf () in the program. then we have to include stdio.h in our C program. Let’s see in detail how the compiler interprets the line.

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