Merge pull request eugenp#2 from RanjeetKaur17/develop.0.2.0

RanjeetKaur17 · web-flow · commit 9dc52f563044 · 2018-08-12T00:13:58.000+04:00
Examples for Reading a file into an arraylist.
diff --git a/core-java-io/src/main/java/com/baeldung/fileparser/BufferedReaderExample.java b/core-java-io/src/main/java/com/baeldung/fileparser/BufferedReaderExample.java
@@ -0,0 +1,24 @@
+package com.baeldung.fileparser;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+
+public class BufferedReaderExample {
+
+    protected static ArrayList<String> generateArrayListFromFile(String filename) throws IOException {
+
+        ArrayList<String> result = new ArrayList<>();
+
+        try (BufferedReader br = new BufferedReader(new FileReader(filename))) {
+
+            while (br.ready()) {
+                result.add(br.readLine());
+            }
+            return result;
+        }
+
+    }
+
+}
diff --git a/core-java-io/src/main/java/com/baeldung/fileparser/FileReaderExample.java b/core-java-io/src/main/java/com/baeldung/fileparser/FileReaderExample.java
@@ -0,0 +1,31 @@
+package com.baeldung.fileparser;
+
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+
+public class FileReaderExample {
+
+    protected static ArrayList<String> generateArrayListFromFile(String filename) throws IOException {
+
+        ArrayList<String> result = new ArrayList<>();
+
+        try (FileReader f = new FileReader(filename)) {
+            StringBuffer sb = new StringBuffer();
+            while (f.ready()) {
+                char c = (char) f.read();
+                if (c == '\n') {
+                    result.add(sb.toString());
+                    sb = new StringBuffer();
+                } else {
+                    sb.append(c);
+                }
+            }
+            if (sb.length() > 0) {
+                result.add(sb.toString());
+            }
+        }
+        
+        return result;
+    }
+}
diff --git a/core-java-io/src/main/java/com/baeldung/fileparser/FilesReadLinesExample.java b/core-java-io/src/main/java/com/baeldung/fileparser/FilesReadLinesExample.java
@@ -0,0 +1,18 @@
+package com.baeldung.fileparser;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.List;
+
+public class FilesReadLinesExample {
+
+    protected static ArrayList<String> generateArrayListFromFile(String filename) throws IOException {
+        
+        List<String> result = Files.readAllLines(Paths.get(filename));
+        
+        return (ArrayList<String>) result;
+    }
+
+}
diff --git a/core-java-io/src/main/java/com/baeldung/fileparser/ScannerIntExample.java b/core-java-io/src/main/java/com/baeldung/fileparser/ScannerIntExample.java
@@ -0,0 +1,24 @@
+package com.baeldung.fileparser;
+
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Scanner;
+
+public class ScannerIntExample {
+
+    protected static ArrayList<Integer> generateArrayListFromFile(String filename) throws IOException {
+        
+        ArrayList<Integer> result = new ArrayList<>();
+
+        try (Scanner s = new Scanner(new FileReader(filename))) {
+
+            while (s.hasNext()) {
+                result.add(s.nextInt());
+            }
+            return result;
+        }
+
+    }
+
+}
diff --git a/core-java-io/src/main/java/com/baeldung/fileparser/ScannerStringExample.java b/core-java-io/src/main/java/com/baeldung/fileparser/ScannerStringExample.java
@@ -0,0 +1,24 @@
+package com.baeldung.fileparser;
+
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Scanner;
+
+public class ScannerStringExample {
+
+    protected static ArrayList<String> generateArrayListFromFile(String filename) throws IOException {
+        
+        ArrayList<String> result = new ArrayList<>();
+
+        try (Scanner s = new Scanner(new FileReader(filename))) {
+
+            while (s.hasNext()) {
+                result.add(s.nextLine());
+            }
+            return result;
+        }
+
+    }
+
+}
diff --git a/core-java-io/src/test/java/com/baeldung/fileparser/BufferedReaderUnitTest.java b/core-java-io/src/test/java/com/baeldung/fileparser/BufferedReaderUnitTest.java
@@ -0,0 +1,19 @@
+package com.baeldung.fileparser;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.junit.Test;
+
+public class BufferedReaderUnitTest {
+
+    protected static final String TEXT_FILENAME = "src/test/resources/sampleTextFile.txt";
+    
+    @Test
+    public void whenParsingExistingTextFile_thenGetArrayList() throws IOException {
+        List<String> lines = BufferedReaderExample.generateArrayListFromFile(TEXT_FILENAME);
+        assertTrue("File does not has 2 lines", lines.size() == 2);
+    }
+}
diff --git a/core-java-io/src/test/java/com/baeldung/fileparser/FileReaderUnitTest.java b/core-java-io/src/test/java/com/baeldung/fileparser/FileReaderUnitTest.java
@@ -0,0 +1,19 @@
+package com.baeldung.fileparser;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.junit.Test;
+
+public class FileReaderUnitTest {
+
+    protected static final String TEXT_FILENAME = "src/test/resources/sampleTextFile.txt";
+    
+    @Test
+    public void whenParsingExistingTextFile_thenGetArrayList() throws IOException {
+        List<String> lines = FileReaderExample.generateArrayListFromFile(TEXT_FILENAME);
+        assertTrue("File does not has 2 lines", lines.size() == 2);
+    }
+}
diff --git a/core-java-io/src/test/java/com/baeldung/fileparser/FilesReadAllLinesUnitTest.java b/core-java-io/src/test/java/com/baeldung/fileparser/FilesReadAllLinesUnitTest.java
@@ -0,0 +1,19 @@
+package com.baeldung.fileparser;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.junit.Test;
+
+public class FilesReadAllLinesUnitTest {
+
+    protected static final String TEXT_FILENAME = "src/test/resources/sampleTextFile.txt";
+
+    @Test
+    public void whenParsingExistingTextFile_thenGetArrayList() throws IOException {
+        List<String> lines = FilesReadLinesExample.generateArrayListFromFile(TEXT_FILENAME);
+        assertTrue("File does not has 2 lines", lines.size() == 2);
+    }
+}
diff --git a/core-java-io/src/test/java/com/baeldung/fileparser/ScannerIntUnitTest.java b/core-java-io/src/test/java/com/baeldung/fileparser/ScannerIntUnitTest.java
@@ -0,0 +1,19 @@
+package com.baeldung.fileparser;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.junit.Test;
+
+public class ScannerIntUnitTest {
+
+    protected static final String NUMBER_FILENAME = "src/test/resources/sampleNumberFile.txt";
+    
+    @Test
+    public void whenParsingExistingTextFile_thenGetIntArrayList() throws IOException {
+        List<Integer> numbers = ScannerIntExample.generateArrayListFromFile(NUMBER_FILENAME);
+        assertTrue("File does not has 2 lines", numbers.size() == 2);
+    }
+}
diff --git a/core-java-io/src/test/java/com/baeldung/fileparser/ScannerStringUnitTest.java b/core-java-io/src/test/java/com/baeldung/fileparser/ScannerStringUnitTest.java
@@ -0,0 +1,19 @@
+package com.baeldung.fileparser;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+import java.util.List;
+
+import org.junit.Test;
+
+public class ScannerStringUnitTest {
+
+    protected static final String TEXT_FILENAME = "src/test/resources/sampleTextFile.txt";
+    
+    @Test
+    public void whenParsingExistingTextFile_thenGetArrayList() throws IOException {
+        List<String> lines = ScannerStringExample.generateArrayListFromFile(TEXT_FILENAME);
+        assertTrue("File does not has 2 lines", lines.size() == 2);
+    }
+}
diff --git a/core-java-io/src/test/resources/sampleNumberFile.txt b/core-java-io/src/test/resources/sampleNumberFile.txt
@@ -0,0 +1,2 @@
+111
+222
diff --git a/core-java-io/src/test/resources/sampleTextFile.txt b/core-java-io/src/test/resources/sampleTextFile.txt
@@ -0,0 +1,2 @@
+Hello 
+World
