This is how I did it.
The Code
import java.io.File;
public class FileAssert {
/**
* Pretty print the directory tree and its file names.
*
* @param folder
* must be a folder.
* @return
*/
public static String printDirectoryTree(File folder) {
if (!folder.isDirectory()) {
throw new IllegalArgumentException("folder is not a Directory");
}
int indent = 0;
StringBuilder sb = new StringBuilder();
printDirectoryTree(folder, indent, sb);
return sb.toString();
}
private static void printDirectoryTree(File folder, int indent,
StringBuilder sb) {
if (!folder.isDirectory()) {
throw new IllegalArgumentException("folder is not a Directory");
}
sb.append(getIndentString(indent));
sb.append("+--");
sb.append(folder.getName());
sb.append("/");
sb.append("\n");
for (File file : folder.listFiles()) {
if (file.isDirectory()) {
printDirectoryTree(file, indent + 1, sb);
} else {
printFile(file, indent + 1, sb);
}
}
}
private static void printFile(File file, int indent, StringBuilder sb) {
sb.append(getIndentString(indent));
sb.append("+--");
sb.append(file.getName());
sb.append("\n");
}
private static String getIndentString(int indent) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < indent; i++) {
sb.append("| ");
}
return sb.toString();
}
}
The Result
+--folder1/
| +--a.txt
| +--folder2/
| | +--b1.txt
| | +--b2.txt
| | +--b3.txt
| | +--folder3/
| +--folder4/
The UnitTest
import static org.junit.Assert.*;
import java.io.File;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TemporaryFolder;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
@RunWith(JUnit4.class)
public class FileAssertTest {
@Rule
public TemporaryFolder temporaryFolder = new TemporaryFolder();
private File folder1;
@Before
public void setUp() {
folder1 = temporaryFolder.newFolder("folder1");
}
@Test
public void testPrintDirectoryTreeWhenFolderIsEmpty() {
// Invoke
String actual = FileAssert.printDirectoryTree(folder1);
// Verify
assertEquals("+--folder1/\n", actual);
}
private static final String EXPECTED_FCOF = "" + "+--folder1/\n"
+ "| +--a.txt\n";
@Test
public void testPrintDirectoryTreeWhenFolderContainsOneFile()
throws Exception {
// Setup
File aFile = new File(folder1, "a.txt");
assertTrue(aFile.createNewFile());
// Invoke
String actual = FileAssert.printDirectoryTree(folder1);
// Verify
assertEquals(EXPECTED_FCOF, actual);
}
private static final String EXPECTED_COMPLEX = "+--folder1/\n"
+ "| +--a.txt\n" + "| +--folder2/\n" + "| | +--b1.txt\n"
+ "| | +--b2.txt\n" + "| | +--b3.txt\n" + "| | +--folder3/\n"
+ "| +--folder4/\n";
@Test
public void testPrintDirectoryTreeComplex() throws Exception {
// Setup
File aFile = new File(folder1, "a.txt");
assertTrue(aFile.createNewFile());
File folder2 = new File(folder1, "folder2");
assertTrue(folder2.mkdir());
File b1File = new File(folder2, "b1.txt");
assertTrue(b1File.createNewFile());
File b2File = new File(folder2, "b2.txt");
assertTrue(b2File.createNewFile());
File folder3 = new File(folder2, "folder3");
assertTrue(folder3.mkdir());
File b3File = new File(folder2, "b3.txt");
assertTrue(b3File.createNewFile());
File folder4 = new File(folder1, "folder4");
assertTrue(folder4.mkdir());
// Invoke
String actual = FileAssert.printDirectoryTree(folder1);
// Verify
assertEquals(EXPECTED_COMPLEX, actual);
}
}
file directory printing pretty-printing
