Java에서 파일을 읽고 파일을 문자열로 변환하는 방법은 무엇입니까? (5가지 방법)

게시 됨: 2021-11-21
Java에서 파일을 읽고 파일을 문자열로 변환하는 방법은 무엇입니까? (5가지 방법)

파일을 String으로 읽는 가장 간단한 방법은 무엇입니까? Java에서 일반 텍스트 파일을 읽으시겠습니까? File 객체를 String 객체로 어떻게 변환하시겠습니까? 파일을 읽고 String으로 변환하는 방법에는 여러 가지가 있습니다.

Java에서 전체 텍스트 파일을 문자열로 변환하는 총 5가지 방법이 있습니다.

  1. Files.readString()
  2. Files.readAllLines(Paths.get(경로), StandardCharsets.UTF_8);
  3. FileUtils.readFileToString(새 파일(경로), StandardCharsets.UTF_8); – Apache Commons IO 종속성
  4. Files.lines()
  5. Files.newBufferedReader()

시작하자:

  • Apache Commons IO 종속성 아래에 추가해야 합니다.
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       < dependency >
             < groupId > commons - io < / groupId >
             < artifactId > commons - io < / artifactId >
             < version > 2.11.0 < / version >
         < / dependency >
  • CrunchifyConvertFileToString.java 클래스를 생성합니다.
  • 아래 코드를 복사하여 붙여넣습니다.

CrunchifyConvertFileToString.java

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package crunchify . com . java . tutorials ;
 
import org . apache . commons . io . FileUtils ;
 
import java . io . File ;
import java . io . IOException ;
import java . nio . charset . StandardCharsets ;
import java . nio . file . Files ;
import java . nio . file . Paths ;
import java . util . List ;
 
/**
* @author Crunchify.com
* Program: In Java How to Read a File and Convert File to String? (5 different ways)
*/
 
public class CrunchifyConvertFileToString {
     public static void main ( String [ ] args ) {
 
         // Files.readString()
         crunchifyFilesReadString ( ) ;
 
         // Files.readAllLines(Paths.get();
         crunchifyFilesReadAllLines ( ) ;
 
         // FileUtils.readFileToString(new File();
         // Apache Commons IO method
         crunchifyFileUtilsReadFileToString ( ) ;
 
         // Files.lines()
         // Please visit: https://crunchify.me/3CDrP7N
         crunchifyFilesLines ( ) ;
 
         // Files.newBufferedReader()
         // Please visit: https://crunchify.me/3CDrP7N
         crunchifyFilesNewBufferedReader ( ) ;
 
     }
 
 
     /*
    Method-1: Files.readString()
     */
     private static void crunchifyFilesReadString ( ) {
         String crunchifyFilePath = "/Users/app/Downloads/crunchify-file-to-string.txt" ;
 
         try {
             crunchifyLog ( "\n================= Files.readString() =================" ) ;
 
             // Files: This class consists exclusively of static methods that operate on files, directories, or other types of files.
             // Paths: This class consists exclusively of static methods that return a Path by converting a path string or URI.
             // get(): Converts a path string, or a sequence of strings that when joined form a path string, to a Path.
 
             String crunchifyFileData = Files . readString ( Paths . get ( crunchifyFilePath ) ) ;
 
             crunchifyLog ( crunchifyFileData ) ;
 
         } catch ( IOException exception ) {
             exception . printStackTrace ( ) ;
         }
     }
 
     /*
    Simple Logging Utility
     */
     private static void crunchifyLog ( Object crunchifyFileData ) {
 
         System . out . println ( crunchifyFileData ) ;
     }
 
     /*
    Method-2: Files.readAllLines(Paths.get();
     */
     private static void crunchifyFilesReadAllLines ( ) {
 
         crunchifyLog ( "================= Files.readAllLines() =================" ) ;
 
         String crunchifyFilePath = "/Users/app/Downloads/crunchify-file-to-string.txt" ;
 
         try {
 
             // readAllLines(): Read all lines from a file. This method ensures that the file is closed when
             // all bytes have been read or an I/O error, or other runtime exception, is thrown.
             // Bytes from the file are decoded into characters using the specified charset.
 
             // This method recognizes the following as line terminators:
 
             /*  \u000D followed by \u000A, CARRIAGE RETURN followed by LINE FEED
                \u000A, LINE FEED
                \u000D, CARRIAGE RETURN
            */
 
             List < String > crunchifyFileData = Files . readAllLines ( Paths . get ( crunchifyFilePath ) , StandardCharsets . UTF_8 ) ;
 
             crunchifyLog ( crunchifyFileData ) ;
 
         } catch ( IOException exception ) {
             exception . printStackTrace ( ) ;
         }
 
     }
 
     /*
    Method-3: FileUtils.readFileToString(new File();
    Apache Commons IO:  <dependency><groupId>commons-io</groupId><artifactId>commons-io</artifactId><version>2.6</version></dependency>
     */
     private static void crunchifyFileUtilsReadFileToString ( ) {
 
         crunchifyLog ( "\n================= FileUtils.readFileToString() =================" ) ;
 
         String crunchifyFilePath = "/Users/app/Downloads/crunchify-file-to-string.txt" ;
 
         try {
 
             // readFileToString: Reads the contents of a file into a String. The file is always closed.
             String crunchifyFileData = FileUtils . readFileToString ( new File ( crunchifyFilePath ) , StandardCharsets . UTF_8 ) ;
             // UTF_8: Eight-bit UCS Transformation Format.
 
             crunchifyLog ( crunchifyFileData ) ;
         } catch ( IOException exception ) {
             exception . printStackTrace ( ) ;
         }
 
     }
 
     /*
    Method-4: Files.lines()
    */
     private static void crunchifyFilesLines ( ) {
 
         // Please visit: https://crunchify.me/3CDrP7N
     }
 
     /*
    Method-5: Files.newBufferedReader()
    */
     private static void crunchifyFilesNewBufferedReader ( ) {
 
         // Please visit: https://crunchify.me/3CDrP7N
     }
 
}
 

IntelliJ IDEA 콘솔 결과:

위의 프로그램을 Java 응용 프로그램으로 실행하면 아래와 같은 결과를 볼 수 있습니다.

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================= Files . readString ( ) =================
Five Ways to Read File and Convert it to String : )
 
Files . readString ( )
Files . readAllLines ( Paths . get ( path ) , StandardCharsets . UTF_8 ) ;
FileUtils . readFileToString ( new File ( path ) , StandardCharsets . UTF_8 ) ;
Files . lines ( )
Files . newBufferedReader ( )
 
================= Files . readAllLines ( ) =================
[ Five Ways to Read File and Convert it to String : ) , , Files . readString ( ) , Files . readAllLines ( Paths . get ( path ) , StandardCharsets . UTF_8 ) ; , FileUtils . readFileToString ( new File ( path ) , StandardCharsets . UTF_8 ) ; , Files . lines ( ) , Files . newBufferedReader ( ) ]
 
================= FileUtils . readFileToString ( ) =================
Five Ways to Read File and Convert it to String : )
 
Files . readString ( )
Files . readAllLines ( Paths . get ( path ) , StandardCharsets . UTF_8 ) ;
FileUtils . readFileToString ( new File ( path ) , StandardCharsets . UTF_8 ) ;
Files . lines ( )
Files . newBufferedReader ( )
 
 
Process finished with exit code 0

위의 코드를 실행하는 데 문제가 있으면 알려주십시오.

다음은 method4 및 method-5를 설명하는 자습서입니다.

Java 8 스트림을 사용하여 파일을 한 줄씩 읽는 방법 – Files.lines() 및 Files.newBufferedReader() 유틸리티 API