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JAVA-2105: Move articles out of core-java-io module

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This commit is contained in:
Krzysiek
2020-07-13 21:17:54 +02:00
parent 6d085ce9f1
commit f0aefb34fa
8 changed files with 18 additions and 28 deletions
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2
core-java-modules/core-java-io-conversions-2/README.md
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@@ -6,4 +6,6 @@ This module contains articles about core Java input/output(IO) conversions.
- [Java InputStream to String](https://www.baeldung.com/convert-input-stream-to-string)
- [Java – Write an InputStream to a File](https://www.baeldung.com/convert-input-stream-to-a-file)
- [Converting a BufferedReader to a JSONObject](https://www.baeldung.com/java-bufferedreader-to-jsonobject)
- [Reading a CSV File into an Array](https://www.baeldung.com/java-csv-file-array)
- [How to Write to a CSV File in Java](https://www.baeldung.com/java-csv)
- More articles: [[<-- prev]](/core-java-modules/core-java-io-conversions)

7
core-java-modules/core-java-io-conversions-2/pom.xml
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@@ -26,6 +26,12 @@
<artifactId>json</artifactId>
<version>${json.version}</version>
</dependency>
<dependency>
<groupId>com.opencsv</groupId>
<artifactId>opencsv</artifactId>
<version>${opencsv.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
@@ -40,6 +46,7 @@
<properties>
<json.version>20200518</json.version>
<opencsv.version>4.1</opencsv.version>
</properties>
</project>

22
core-java-modules/core-java-io-conversions-2/src/main/java/com/baeldung/csv/WriteCsvFileExample.java Normal file
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@@ -0,0 +1,22 @@
package com.baeldung.csv;
import java.util.stream.Collectors;
import java.util.stream.Stream;
public class WriteCsvFileExample {
public String convertToCSV(String[] data) {
return Stream.of(data)
.map(this::escapeSpecialCharacters)
.collect(Collectors.joining(","));
}
public String escapeSpecialCharacters(String data) {
String escapedData = data.replaceAll("\\R", " ");
if (data.contains(",") || data.contains("\"") || data.contains("'")) {
data = data.replace("\"", "\"\"");
escapedData = "\"" + data + "\"";
}
return escapedData;
}
}

97
core-java-modules/core-java-io-conversions-2/src/test/java/com/baeldung/csv/ReadCSVInArrayUnitTest.java Normal file
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@@ -0,0 +1,97 @@
package com.baeldung.csv;
import com.opencsv.CSVReader;
import org.junit.Assert;
import org.junit.Test;
import java.io.*;
import java.util.*;
public class ReadCSVInArrayUnitTest {
public static final String COMMA_DELIMITER = ",";
public static final String CSV_FILE = "src/test/resources/book.csv";
public static final List<List<String>> EXPECTED_ARRAY = Collections.unmodifiableList(new ArrayList<List<String>>() {
{
add(new ArrayList<String>() {
{
add("Mary Kom");
add("Unbreakable");
}
});
add(new ArrayList<String>() {
{
add("Kapil Isapuari");
add("Farishta");
}
});
}
});
@Test
public void givenCSVFile_whenBufferedReader_thenContentsAsExpected() throws IOException {
List<List<String>> records = new ArrayList<List<String>>();
try (BufferedReader br = new BufferedReader(new FileReader(CSV_FILE))) {
String line = "";
while ((line = br.readLine()) != null) {
String[] values = line.split(COMMA_DELIMITER);
records.add(Arrays.asList(values));
}
} catch (Exception e) {
e.printStackTrace();
}
for (int i = 0; i < EXPECTED_ARRAY.size(); i++) {
Assert.assertArrayEquals(EXPECTED_ARRAY.get(i)
.toArray(),
records.get(i)
.toArray());
}
}
@Test
public void givenCSVFile_whenScanner_thenContentsAsExpected() throws IOException {
List<List<String>> records = new ArrayList<List<String>>();
try (Scanner scanner = new Scanner(new File(CSV_FILE));) {
while (scanner.hasNextLine()) {
records.add(getRecordFromLine(scanner.nextLine()));
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
for (int i = 0; i < EXPECTED_ARRAY.size(); i++) {
Assert.assertArrayEquals(EXPECTED_ARRAY.get(i)
.toArray(),
records.get(i)
.toArray());
}
}
private List<String> getRecordFromLine(String line) {
List<String> values = new ArrayList<String>();
try (Scanner rowScanner = new Scanner(line)) {
rowScanner.useDelimiter(COMMA_DELIMITER);
while (rowScanner.hasNext()) {
values.add(rowScanner.next());
}
}
return values;
}
@Test
public void givenCSVFile_whenOpencsv_thenContentsAsExpected() throws IOException {
List<List<String>> records = new ArrayList<List<String>>();
try (CSVReader csvReader = new CSVReader(new FileReader(CSV_FILE));) {
String[] values = null;
while ((values = csvReader.readNext()) != null) {
records.add(Arrays.asList(values));
}
} catch (Exception e) {
e.printStackTrace();
}
for (int i = 0; i < EXPECTED_ARRAY.size(); i++) {
Assert.assertArrayEquals(EXPECTED_ARRAY.get(i)
.toArray(),
records.get(i)
.toArray());
}
}
}

85
core-java-modules/core-java-io-conversions-2/src/test/java/com/baeldung/csv/WriteCsvFileExampleUnitTest.java Normal file
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@@ -0,0 +1,85 @@
package com.baeldung.csv;
import org.junit.Before;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
public class WriteCsvFileExampleUnitTest {
private static final Logger LOG = LoggerFactory.getLogger(WriteCsvFileExampleUnitTest.class);
private WriteCsvFileExample csvExample;
@Before
public void setupClass() {
csvExample = new WriteCsvFileExample();
}
@Test
public void givenCommaContainingData_whenEscapeSpecialCharacters_stringReturnedInQuotes() {
String data = "three,two,one";
String escapedData = csvExample.escapeSpecialCharacters(data);
String expectedData = "\"three,two,one\"";
assertEquals(expectedData, escapedData);
}
@Test
public void givenQuoteContainingData_whenEscapeSpecialCharacters_stringReturnedFormatted() {
String data = "She said \"Hello\"";
String escapedData = csvExample.escapeSpecialCharacters(data);
String expectedData = "\"She said \"\"Hello\"\"\"";
assertEquals(expectedData, escapedData);
}
@Test
public void givenNewlineContainingData_whenEscapeSpecialCharacters_stringReturnedInQuotes() {
String dataNewline = "This contains\na newline";
String dataCarriageReturn = "This contains\r\na newline and carriage return";
String escapedDataNl = csvExample.escapeSpecialCharacters(dataNewline);
String escapedDataCr = csvExample.escapeSpecialCharacters(dataCarriageReturn);
String expectedData = "This contains a newline";
assertEquals(expectedData, escapedDataNl);
String expectedDataCr = "This contains a newline and carriage return";
assertEquals(expectedDataCr, escapedDataCr);
}
@Test
public void givenNonSpecialData_whenEscapeSpecialCharacters_stringReturnedUnchanged() {
String data = "This is nothing special";
String returnedData = csvExample.escapeSpecialCharacters(data);
assertEquals(data, returnedData);
}
@Test
public void givenDataArray_whenConvertToCSV_thenOutputCreated() throws IOException {
List<String[]> dataLines = new ArrayList<String[]>();
dataLines.add(new String[] { "John", "Doe", "38", "Comment Data\nAnother line of comment data" });
dataLines.add(new String[] { "Jane", "Doe, Jr.", "19", "She said \"I'm being quoted\"" });
File csvOutputFile = File.createTempFile("exampleOutput", ".csv");
try (PrintWriter pw = new PrintWriter(csvOutputFile)) {
dataLines.stream()
.map(csvExample::convertToCSV)
.forEach(pw::println);
} catch (FileNotFoundException e) {
LOG.error("IOException " + e.getMessage());
}
assertTrue(csvOutputFile.exists());
csvOutputFile.deleteOnExit();
}
}

2
core-java-modules/core-java-io-conversions-2/src/test/resources/book.csv Normal file
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@@ -0,0 +1,2 @@
Mary Kom,Unbreakable
Kapil Isapuari,Farishta
1 Mary Kom Unbreakable
2 Kapil Isapuari Farishta