BAEL-2659 - Reading a file in Groovy

core-groovy/src/main/groovy/com/baeldung/file/ReadFile.groovy

@@ -0,0 +1,61 @@
+package com.baeldung.file
+
+class ReadFile {
+
+    /**
+     * reads file content in string using File.text
+     * @param filePath
+     * @return
+     */
+    String readFileString(String filePath) {
+        File file = new File(filePath)
+        String fileContent = file.text
+        return fileContent
+    }
+
+    /**
+     * reads file content in string with encoding using File.getText
+     * @param filePath
+     * @return
+     */
+    String readFileStringWithCharset(String filePath) {
+        File file = new File(filePath)
+        String utf8Content = file.getText("UTF-8")
+        return utf8Content
+    }
+
+    /**
+     * reads file content line by line using withReader and reader.readLine
+     * @param filePath
+     * @return
+     */
+    int readFileLineByLine(String filePath) {
+        File file = new File(filePath)
+        def line, noOfLines = 0;
+        file.withReader { reader ->
+            while ((line = reader.readLine())!=null)
+            {
+                println "${line}"
+                noOfLines++
+            }
+        }
+        return noOfLines
+    }
+
+    /**
+     * reads file content in list of lines
+     * @param filePath
+     * @return
+     */
+    List<String> readFileInList(String filePath) {
+        File file = new File(filePath)
+        def lines = file.readLines()
+        return lines
+    }
+    
+    public static void main(String[] args) {
+        def file = new File("../../src")
+        println file.directorySize
+    }
+
+}

core-groovy/src/main/resources/fileContent.txt

@@ -0,0 +1,3 @@
+Line 1 : Hello World!!!
+Line 2 : This is a file content.
+Line 3 : String content

core-groovy/src/test/groovy/com/baeldung/file/ReadFileUnitTest.groovy

@@ -0,0 +1,58 @@
+package com.baeldung.file
+
+import spock.lang.Specification
+
+class ReadFileUnitTest extends Specification {
+
+    ReadFile readFile
+
+    void setup () {
+        readFile = new ReadFile()
+    }
+
+    def 'Should return file content in string using ReadFile.readFileString given filePath' () {
+        given:
+            def filePath = "src/main/resources/fileContent.txt"
+        when:
+            def fileContent = readFile.readFileString(filePath)
+        then:
+            fileContent
+            fileContent instanceof String
+            fileContent.contains("""Line 1 : Hello World!!!
+Line 2 : This is a file content.
+Line 3 : String content""")
+    
+    }
+
+    def 'Should return UTF-8 encoded file content in string using ReadFile.readFileStringWithCharset given filePath' () {
+        given:
+            def filePath = "src/main/resources/fileContent.txt"
+        when:
+            def noOfLines = readFile.readFileStringWithCharset(filePath)
+        then:
+            noOfLines
+            noOfLines instanceof String
+    }
+    
+    def 'Should return number of lines in File using ReadFile.readFileLineByLine given filePath' () {
+        given:
+            def filePath = "src/main/resources/fileContent.txt"
+        when:
+            def noOfLines = readFile.readFileLineByLine(filePath)
+        then:
+            noOfLines
+            noOfLines instanceof Integer
+            assert noOfLines, 3
+    }
+    
+    def 'Should return File Content in list of lines using ReadFile.readFileInList given filePath' () {
+        given:
+            def filePath = "src/main/resources/fileContent.txt"
+        when:
+            def lines = readFile.readFileInList(filePath)
+        then:
+            lines
+            lines instanceof List<String>
+            assert lines.size(), 3
+    }
+}