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[BAEL-4214] Converting java.util.Properties to HashMap<String,String>

This commit is contained in:
Mateusz Szablak 'Saber-k 2021-01-19 21:40:10 +01:00
parent 7e91f30534
commit a41309f4c6
4 changed files with 238 additions and 0 deletions
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4
core-java-modules/core-java-collections-maps-3/pom.xml
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@ -20,6 +20,10 @@
<artifactId>jmh-core</artifactId>
<version>${jmh-core.version}</version>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
</dependency>
</dependencies>
<properties>

39
core-java-modules/core-java-collections-maps-3/src/main/java/com/baeldung/map/propertieshashmap/PropertiesToHashMapConverter.java Normal file
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@ -0,0 +1,39 @@
package com.baeldung.map.propertieshashmap;
import com.google.common.collect.Maps;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.stream.Collectors;
public class PropertiesToHashMapConverter {
@SuppressWarnings({"rawtypes", "unchecked"})
public static HashMap<String, String> typeCastConvert(Properties prop) {
Map step1 = prop;
Map<String, String> step2 = (Map<String, String>) step1;
return new HashMap<>(step2);
}
public static HashMap<String, String> loopConvert(Properties prop) {
HashMap<String, String> retMap = new HashMap<>();
for (Map.Entry<Object, Object> entry : prop.entrySet()) {
retMap.put(String.valueOf(entry.getKey()), String.valueOf(entry.getValue()));
}
return retMap;
}
public static HashMap<String, String> streamConvert(Properties prop) {
return prop.entrySet().stream().collect(
Collectors.toMap(
e -> String.valueOf(e.getKey()),
e -> String.valueOf(e.getValue()),
(prev, next) -> next, HashMap::new
));
}
public static HashMap<String, String> guavaConvert(Properties prop) {
return Maps.newHashMap(Maps.fromProperties(prop));
}
}

192
core-java-modules/core-java-collections-maps-3/src/test/java/com/baeldung/map/propertieshashmap/PropertiesToHashMapConverterUnitTest.java Normal file
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@ -0,0 +1,192 @@
package com.baeldung.map.propertieshashmap;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Properties;
import static org.junit.jupiter.api.Assertions.*;
class PropertiesToHashMapConverterUnitTest {
private Properties properties;
private final static String propertyFileName = "toHashMap.properties";
@BeforeEach
public void setup() throws IOException {
properties = new Properties();
try (InputStream is = getClass().getClassLoader().getResourceAsStream(propertyFileName)) {
if (is != null) {
properties.load(is);
}
}
}
@Test
public void havingPropertiesLoaded_whenCheck_thenEquals() {
assertEquals(3, properties.size());
assertEquals("str_value", properties.get("property1"));
assertEquals("123", properties.get("property2"));
assertEquals("", properties.get("property3"));
}
@Test
public void whenPropertiesModified_thenTypeSafeIssues() {
compromiseProperties(properties);
assertEquals(5, properties.size());
assertNull(properties.getProperty("property4"));
assertNotEquals(String.class, properties.get("property4").getClass());
assertEquals(456, properties.get("property4"));
assertNull(properties.getProperty("5"));
assertNotEquals(String.class, properties.get(5).getClass());
assertEquals(10.11, properties.get(5));
}
@Test
public void havingNonModifiedProperties_whenTypeCastConvert_thenNoTypeSafeIssues() {
HashMap<String, String> hMap = PropertiesToHashMapConverter.typeCastConvert(properties);
assertEquals(3, hMap.size());
assertEquals(String.class, hMap.get("property1").getClass());
assertEquals(properties.get("property1"), hMap.get("property1"));
assertEquals(String.class, hMap.get("property2").getClass());
assertEquals(properties.get("property2"), hMap.get("property2"));
assertEquals(String.class, hMap.get("property3").getClass());
assertEquals(properties.get("property3"), hMap.get("property3"));
}
@Test
public void havingModifiedProperties_whenTypeCastConvert_thenClassCastException() {
compromiseProperties(properties);
HashMap<String, String> hMap = PropertiesToHashMapConverter.typeCastConvert(properties);
assertEquals(5, hMap.size());
assertThrows(ClassCastException.class, () -> {
String s = hMap.get("property4");
});
assertEquals(Integer.class, ((Object) hMap.get("property4")).getClass());
assertNull(hMap.get("5"));
assertNotNull(hMap.get(5));
assertThrows(ClassCastException.class, () -> {
String s = hMap.get(5);
});
assertEquals(Double.class, ((Object) hMap.get(5)).getClass());
}
@Test
public void havingNonModifiedProperties_whenLoopConvert_thenNoTypeSafeIssues() {
HashMap<String, String> hMap = PropertiesToHashMapConverter.loopConvert(properties);
assertEquals(3, hMap.size());
assertEquals(String.class, hMap.get("property1").getClass());
assertEquals(properties.get("property1"), hMap.get("property1"));
assertEquals(String.class, hMap.get("property2").getClass());
assertEquals(properties.get("property2"), hMap.get("property2"));
assertEquals(String.class, hMap.get("property3").getClass());
assertEquals(properties.get("property3"), hMap.get("property3"));
}
@Test
public void havingModifiedProperties_whenLoopConvert_thenNoClassCastException() {
compromiseProperties(properties);
HashMap<String, String> hMap = PropertiesToHashMapConverter.loopConvert(properties);
assertEquals(5, hMap.size());
assertDoesNotThrow(() -> {
String s = hMap.get("property4");
});
assertEquals(String.class, hMap.get("property4").getClass());
assertEquals("456", hMap.get("property4"));
assertDoesNotThrow(() -> {
String s = hMap.get("5");
});
assertEquals("10.11", hMap.get("5"));
}
@Test
public void havingNonModifiedProperties_whenStreamConvert_thenNoTypeSafeIssues() {
HashMap<String, String> hMap = PropertiesToHashMapConverter.streamConvert(properties);
assertEquals(3, hMap.size());
assertEquals(String.class, hMap.get("property1").getClass());
assertEquals(properties.get("property1"), hMap.get("property1"));
assertEquals(String.class, hMap.get("property2").getClass());
assertEquals(properties.get("property2"), hMap.get("property2"));
assertEquals(String.class, hMap.get("property3").getClass());
assertEquals(properties.get("property3"), hMap.get("property3"));
}
@Test
public void havingModifiedProperties_whenStreamConvert_thenNoClassCastException() {
compromiseProperties(properties);
HashMap<String, String> hMap = PropertiesToHashMapConverter.streamConvert(properties);
assertEquals(5, hMap.size());
assertDoesNotThrow(() -> {
String s = hMap.get("property4");
});
assertEquals(String.class, hMap.get("property4").getClass());
assertEquals("456", hMap.get("property4"));
assertDoesNotThrow(() -> {
String s = hMap.get("5");
});
assertEquals("10.11", hMap.get("5"));
}
@Test
public void havingModifiedProperties_whenLoopConvertAndStreamConvert_thenHashMapsSame() {
compromiseProperties(properties);
HashMap<String, String> hMap1 = PropertiesToHashMapConverter.loopConvert(properties);
HashMap<String, String> hMap2 = PropertiesToHashMapConverter.streamConvert(properties);
assertEquals(hMap2, hMap1);
}
@Test
public void havingNonModifiedProperties_whenGuavaConvert_thenNoTypeSafeIssues() {
HashMap<String, String> hMap = PropertiesToHashMapConverter.guavaConvert(properties);
assertEquals(3, hMap.size());
assertEquals(String.class, hMap.get("property1").getClass());
assertEquals(properties.get("property1"), hMap.get("property1"));
assertEquals(String.class, hMap.get("property2").getClass());
assertEquals(properties.get("property2"), hMap.get("property2"));
assertEquals(String.class, hMap.get("property3").getClass());
assertEquals(properties.get("property3"), hMap.get("property3"));
}
@Test
public void havingModifiedProperties_whenGuavaConvert_thenUnableToConvertAndThrowException() {
compromiseProperties(properties);
assertThrows(Exception.class, () -> PropertiesToHashMapConverter.guavaConvert(properties));
}
@Test
public void havingModifiedPropertiesWithNoIntegerValue_whenGuavaConvert_thenNullPointerException() {
properties.put("property4", 456);
assertThrows(NullPointerException.class, () -> PropertiesToHashMapConverter.guavaConvert(properties));
}
@Test
public void havingModifiedPropertiesWithNoIntegerKey_whenGuavaConvert_thenClassCastException() {
properties.put(5, 10.11);
assertThrows(ClassCastException.class, () -> PropertiesToHashMapConverter.guavaConvert(properties));
}
private void compromiseProperties(Properties prop) {
prop.put("property4", 456);
prop.put(5, 10.11);
}
}

3
core-java-modules/core-java-collections-maps-3/src/test/resources/toHashMap.properties Normal file
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@ -0,0 +1,3 @@
property1=str_value
property2=123
property3=