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[BAEL-19088] - Move articles out of core-java-io part 3

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This commit is contained in:
catalin-burcea
2019-11-15 11:49:14 +02:00
parent 0950c53112
commit 5ec3630590
95 changed files with 114 additions and 180090 deletions
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2
core-java-modules/core-java-io-apis/README.md
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@@ -12,3 +12,5 @@ This module contains articles about core Java input/output(IO) APIs.
- [Quick Use of FilenameFilter](https://www.baeldung.com/java-filename-filter)
- [Guide to BufferedReader](https://www.baeldung.com/java-buffered-reader)
- [Java Scanner](https://www.baeldung.com/java-scanner)
- [Scanner nextLine() Method](https://www.baeldung.com/java-scanner-nextline)
- [Java Scanner hasNext() vs. hasNextLine()](https://www.baeldung.com/java-scanner-hasnext-vs-hasnextline)

17
core-java-modules/core-java-io-apis/pom.xml
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@@ -14,6 +14,23 @@
</parent>
<dependencies>
<!-- logging -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</version>
</dependency>
<dependency> <!-- needed to bridge to slf4j for projects that use the log4j APIs directly -->
<groupId>org.slf4j</groupId>
<artifactId>log4j-over-slf4j</artifactId>
<version>${org.slf4j.version}</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>${lombok.version}</version>
<scope>provided</scope>
</dependency>
<!-- test scoped -->
<dependency>
<groupId>org.assertj</groupId>

96
core-java-modules/core-java-io-apis/src/main/java/com/baeldung/scanner/HasNextVsHasNextLineDemo.java Normal file
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@@ -0,0 +1,96 @@
package com.baeldung.scanner;
import lombok.extern.log4j.Log4j;
import org.apache.log4j.LogManager;
import org.apache.log4j.PropertyConfigurator;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
import java.util.Scanner;
@Log4j
public class HasNextVsHasNextLineDemo {
private static final String LINE = "----------------------------";
private static final String END_LINE = "--------OUTPUT--END---------\n";
private static final String INPUT = new StringBuilder()
.append("magic\tproject\n")
.append(" database: oracle\n")
.append("dependencies:\n")
.append("spring:foo:bar\n")
.append("\n").toString();
private static void hasNextBasic() {
printHeader("hasNext() Basic");
Scanner scanner = new Scanner(INPUT);
while (scanner.hasNext()) {
log.info(scanner.next());
}
log.info(END_LINE);
scanner.close();
}
private static void hasNextWithDelimiter() {
printHeader("hasNext() with delimiter");
Scanner scanner = new Scanner(INPUT);
while (scanner.hasNext()) {
String token = scanner.next();
if ("dependencies:".equals(token)) {
scanner.useDelimiter(":");
}
log.info(token);
}
log.info(END_LINE);
scanner.close();
}
private static void hasNextWithDelimiterFixed() {
printHeader("hasNext() with delimiter FIX");
Scanner scanner = new Scanner(INPUT);
while (scanner.hasNext()) {
String token = scanner.next();
if ("dependencies:".equals(token)) {
scanner.useDelimiter(":|\\s+");
}
log.info(token);
}
log.info(END_LINE);
scanner.close();
}
private static void addLineNumber() {
printHeader("add line number by hasNextLine() ");
Scanner scanner = new Scanner(INPUT);
int i = 0;
while (scanner.hasNextLine()) {
log.info(String.format("%d|%s", ++i, scanner.nextLine()));
}
log.info(END_LINE);
scanner.close();
}
private static void printHeader(String title) {
log.info(LINE);
log.info(title);
log.info(LINE);
}
public static void main(String[] args) throws IOException {
setLogger();
hasNextBasic();
hasNextWithDelimiter();
hasNextWithDelimiterFixed();
addLineNumber();
}
//overwrite the logger config
private static void setLogger() throws IOException {
InputStream is = HasNextVsHasNextLineDemo.class.getResourceAsStream("/scanner/log4j.properties");
Properties props = new Properties();
props.load(is);
LogManager.resetConfiguration();
PropertyConfigurator.configure(props);
}
}

4
core-java-modules/core-java-io-apis/src/main/resources/scanner/log4j.properties Normal file
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@@ -0,0 +1,4 @@
log4j.rootLogger=INFO, A1
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=[DEMO]%m%n

44
core-java-modules/core-java-io-apis/src/test/java/com/baeldung/scannernextline/ScannerNextLineUnitTest.java Normal file
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@@ -0,0 +1,44 @@
package com.baeldung.scannernextline;
import org.junit.Test;
import java.util.NoSuchElementException;
import java.util.Scanner;
import static org.junit.Assert.assertEquals;
public class ScannerNextLineUnitTest {
@Test
public void whenReadingLines_thenCorrect() {
String input = "Scanner\nTest\n";
try (Scanner scanner = new Scanner(input)) {
assertEquals("Scanner", scanner.nextLine());
assertEquals("Test", scanner.nextLine());
}
}
@Test
public void whenReadingPartialLines_thenCorrect() {
String input = "Scanner\n";
try (Scanner scanner = new Scanner(input)) {
scanner.useDelimiter("");
scanner.next();
assertEquals("canner", scanner.nextLine());
}
}
@Test(expected = NoSuchElementException.class)
public void givenNoNewLine_whenReadingNextLine_thenThrowNoSuchElementException() {
try (Scanner scanner = new Scanner("")) {
String result = scanner.nextLine();
}
}
@Test(expected = IllegalStateException.class)
public void givenScannerIsClosed_whenReadingNextLine_thenThrowIllegalStateException() {
Scanner scanner = new Scanner("");
scanner.close();
String result = scanner.nextLine();
}
}