BAEL-8521: Mapping to String in Mapstruct (#19086)

* BAEL-8521: Mapping to String in Mapstruct

* BAEL-9429: Clean up pom.xml for MapStruct string mapping examples

* BAEL-8521: Mapping to String in Mapstruct

Author: samuelnjoki29

core-java-modules/core-java-string-conversions-4/pom.xml

@@ -2,6 +2,7 @@
 <project xmlns="http://maven.apache.org/POM/4.0.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    
     <modelVersion>4.0.0</modelVersion>
     <artifactId>core-java-string-conversions-4</artifactId>
     <packaging>jar</packaging>
@@ -14,32 +15,86 @@
     </parent>
 
     <dependencies>
+        <!-- ICU4J for internationalization utilities -->
         <dependency>
             <groupId>com.ibm.icu</groupId>
             <artifactId>icu4j</artifactId>
             <version>${icu4j.version}</version>
         </dependency>
+
+        <!-- Apache Commons Text for text manipulation -->
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-text</artifactId>
             <version>${commons-text.version}</version>
         </dependency>
+
+        <!-- MapStruct for compile-time mapping -->
+        <dependency>
+            <groupId>org.mapstruct</groupId>
+            <artifactId>mapstruct</artifactId>
+            <version>1.6.0</version>
+        </dependency>
+
+        <!-- JUnit 5 for testing -->
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.10.2</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
         <finalName>core-java-string-conversions-4</finalName>
+
         <resources>
             <resource>
                 <directory>src/main/resources</directory>
                 <filtering>true</filtering>
             </resource>
         </resources>
+
+        <plugins>
+            <!-- Compiler plugin for Java 17 and MapStruct annotation processing -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.11.0</version>
+                <configuration>
+                    <source>17</source>
+                    <target>17</target>
+                    <annotationProcessorPaths>
+                        <path>
+                            <groupId>org.mapstruct</groupId>
+                            <artifactId>mapstruct-processor</artifactId>
+                            <version>1.6.0</version>
+                        </path>
+                    </annotationProcessorPaths>
+                    <compilerArgs>
+                        <arg>-parameters</arg>
+                    </compilerArgs>
+                </configuration>
+            </plugin>
+
+            <!-- Surefire plugin to run unit tests -->
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>3.1.2</version>
+                <configuration>
+                    <includes>
+                        <include>**/*UnitTest.java</include>
+                    </includes>
+                </configuration>
+            </plugin>
+        </plugins>
     </build>
 
     <properties>
         <icu4j.version>61.1</icu4j.version>
-        <argLine>-Djava.locale.providers=COMPAT</argLine>
         <commons-text.version>1.9</commons-text.version>
+        <argLine>-Djava.locale.providers=COMPAT</argLine>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
-
 </project>

core-java-modules/core-java-string-conversions-4/src/main/java/com/baeldung/mapstructstringmapping/Event.java

@@ -0,0 +1,25 @@
+package com.baeldung.mapstructstringmapping;
+
+import java.time.LocalDate;
+
+public class Event {
+
+    private String name;
+    private LocalDate eventDate;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public LocalDate getEventDate() {
+        return eventDate;
+    }
+
+    public void setEventDate(LocalDate eventDate) {
+        this.eventDate = eventDate;
+    }
+}

core-java-modules/core-java-string-conversions-4/src/main/java/com/baeldung/mapstructstringmapping/EventDTO.java

@@ -0,0 +1,23 @@
+package com.baeldung.mapstructstringmapping;
+
+public class EventDTO {
+
+    private String name;
+    private String eventDate;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getEventDate() {
+        return eventDate;
+    }
+
+    public void setEventDate(String eventDate) {
+        this.eventDate = eventDate;
+    }
+}

core-java-modules/core-java-string-conversions-4/src/main/java/com/baeldung/mapstructstringmapping/EventMapper.java

@@ -0,0 +1,14 @@
+package com.baeldung.mapstructstringmapping;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+import org.mapstruct.factory.Mappers;
+
+@Mapper
+public interface EventMapper {
+
+    EventMapper INSTANCE = Mappers.getMapper(EventMapper.class);
+
+    @Mapping(source = "eventDate", target = "eventDate", dateFormat = "yyyy-MM-dd")
+    EventDTO toEventDTO(Event event);
+}

core-java-modules/core-java-string-conversions-4/src/main/java/com/baeldung/mapstructstringmapping/Person.java

@@ -0,0 +1,23 @@
+package com.baeldung.mapstructstringmapping;
+
+public class Person {
+
+    private String name;
+    private int age;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+}

core-java-modules/core-java-string-conversions-4/src/main/java/com/baeldung/mapstructstringmapping/PersonDTO.java

@@ -0,0 +1,23 @@
+package com.baeldung.mapstructstringmapping;
+
+public class PersonDTO {
+
+    private String name;
+    private String age;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getAge() {
+        return age;
+    }
+
+    public void setAge(String age) {
+        this.age = age;
+    }
+}

core-java-modules/core-java-string-conversions-4/src/main/java/com/baeldung/mapstructstringmapping/PersonMapper.java

@@ -0,0 +1,22 @@
+package com.baeldung.mapstructstringmapping;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+import org.mapstruct.NullValueMappingStrategy;
+import org.mapstruct.Named;
+import org.mapstruct.factory.Mappers;
+
+@Mapper(nullValueMappingStrategy = NullValueMappingStrategy.RETURN_DEFAULT)
+public interface PersonMapper {
+
+    PersonMapper INSTANCE = Mappers.getMapper(PersonMapper.class);
+
+    @Mapping(target = "name", qualifiedByName = "mapName")
+    @Mapping(target = "age", expression = "java(String.valueOf(person.getAge()))")
+    PersonDTO toDTO(Person person);
+
+    @Named("mapName")
+    default String mapName(String name) {
+        return name == null ? "Unknown" : name;
+    }
+}

core-java-modules/core-java-string-conversions-4/src/main/java/com/baeldung/mapstructstringmapping/Status.java

@@ -0,0 +1,7 @@
+package com.baeldung.mapstructstringmapping;
+
+public enum Status {
+    ACTIVE,
+    INACTIVE,
+    PENDING
+}

core-java-modules/core-java-string-conversions-4/src/main/java/com/baeldung/mapstructstringmapping/User.java

@@ -0,0 +1,23 @@
+package com.baeldung.mapstructstringmapping;
+
+public class User {
+
+    private String username;
+    private Status status;
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public Status getStatus() {
+        return status;
+    }
+
+    public void setStatus(Status status) {
+        this.status = status;
+    }
+}

core-java-modules/core-java-string-conversions-4/src/main/java/com/baeldung/mapstructstringmapping/UserDTO.java

@@ -0,0 +1,23 @@
+package com.baeldung.mapstructstringmapping;
+
+public class UserDTO {
+
+    private String username;
+    private String status;
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getStatus() {
+        return status;
+    }
+
+    public void setStatus(String status) {
+        this.status = status;
+    }
+}