---
title: configuration
order: 6
category:
- Guide
description: MapStructPlus MapStructPlus配置项 configuration
---

MapStructPlus provides multiple configuration items to specify some behavior when the conversion interface is generated.

## How to use it

In the module that needs to be configured, create a new configuration class an annotate it with `@MapperConfig` annotation.

In a module, there can noly be one class with this annotation.

Also, note that **the configuration classes must be placed in the module to be effective**.

eg：

```java
@MapperConfig(adapterClassName = "DemoConvertMapperAdapter",
    adapterPackage = "io.github.linpeilie.adapter",
    mapAdapterClassName = "DemoMapConvertMapperAdapter")
public class MapStructPlusConfiguration {
}
```

In addition, the configuration property supports **adding compilation parameters** to the compiler in the form of `-Akey=value`.

For example, when using Maven, you can use the `compilerArgs` property in the `maven-compiler-plugin` plugin configuration to configure delivery, for example:

**And configuration in this way takes precedence**, that is, when the mode and configuration class exist together, the property configured in this way takes precedence. This feature is supported from `1.3.0`.

eg:

```xml
<build>
  <plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-compiler-plugin</artifactId>
      <version>3.8.0</version>
      <configuration>
        <source>${maven.compiler.source}</source>
        <target>${maven.compiler.target}</target>
        <annotationProcessorPaths>
          <path>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>${lombok.version}</version>
          </path>
          <path>
            <groupId>io.github.linpeilie</groupId>
            <artifactId>mapstruct-plus-processor</artifactId>
            <version>${mapstruct-plus.version}</version>
          </path>
          <path>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok-mapstruct-binding</artifactId>
            <version>0.2.0</version>
          </path>
        </annotationProcessorPaths>
        <compilerArgs>
          <arg>-Amapstruct.plus.adapterClassName=DemoConvertMapperAdapter</arg>
          <arg>-Amapstruct.plus.adapterPackage=io.github.linpeilie.adapter</arg>
          <arg>-Amapstruct.plus.mapAdapterClassName=DemoMapConvertMapperAdapter</arg>
        </compilerArgs>
      </configuration>
    </plugin>
  </plugins>
</build>
```

## Configuration Item

### mapperPackage

- **Description**：The package name of the generated Mapper transformation interfaces
- **Type**：`String`
- **Default**：The default is under the same package as the class to be converted.
- **Compile Parameter**：`-Amapstruct.plus.mapperPackage`

### unmappedSourcePolicy

- **Description**：Policy when there is no corresponding attribute in the source class
- **Type**：`ReportingPolicy`
- **Optional**：
  - `IGNORE`：ignore
  - `WARN`：print warning log
  - `ERROR`：throw exception
- **Default**：`IGNORE`
- **Compile Parameter**：`-Amapstruct.plus.unmappedSourcePolicy`

### unmappedTargetPolicy

- **Description**：Policy when there is no corresponding attribute in the target class
- **Type**：`ReportingPolicy`
- **Optional**：
  - `IGNORE`：ignore
  - `WARN`：print warning log
  - `ERROR`：throw exception
- **Default**：`IGNORE`
- **Compile Parameter**：`-Amapstruct.plus.unmappedTargetPolicy`

### nullValueMappingStrategy

- **Description**：Null object handing policy
- **Type**：`NullValueMappingStrategy`
- **Optional**：
  - `RETURN_NULL`：return null
  - `RETURN_DEFAULT`：return default value
- **Default**：`RETURN_NULL`
- **Compile Parameter**：`-Amapstruct.plus.nullValueMappingStrategy`

### nullValuePropertyMappingStrategy

- **Description**：Policy to deal with when the property value is `null`
- **Type**：`NullValuePropertyMappingStrategy`
- **Optional**：
  - `SET_TO_NULL`：setting is null
  - `SET_TO_DEFAULT`：setting is default value
  - `IGNORE`：ignore
- **Default**：`SET_TO_NULL`
- **Compile Parameter**：`-Amapstruct.plus.nullValuePropertyMappingStrategy`

### builder

- **Description**：Constructor mode configuration, MapStruct loses the parent class property when used with Lombok's builder, so the default constructor mode is turned off.
- **Type**：`Builder`
- **Optional**：
  - `buildMethod`：The constructor creates the constructor when the type is to be build
  - `disableBuilder`：Open/Close the constructor, and if closed, use only regular getters/setters
- **Default**：
  - `buildMethod`：`build`
  - `disableBuilder`：`true`
- **Compile Parameter**：
  - `-Amapstruct.plus.builder.buildMethod`
  - `-Amapstruct.plus.builder.disableBuilder`

### adapterPackage

> since `1.2.3`

- **Description**：The package name of ConvertAdapterClass and MapConvertMapperAdapter
- **Type**：`String`
- **Default**：io.github.linpeilie
- **Compile Parameter**：`-Amapstruct.plus.adapterPackage`

### adapterClassName

> since `1.2.3`

- **Description**：the class name of ConvertAdapterClass
- **Type**：`String`
- **Default**：ConvertMapperAdapter
- **Compile Parameter**：`-Amapstruct.plus.adapterClassName`

### mapAdapterClassName

> since `1.2.3`

- **Description**：the class name of MapConvertMapperAdapter
- **Type**：`String`
- **Default**：MapConvertMapperAdapter
- **Compile Parameter**：`-Amapstruct.plus.mapAdapterClassName`

### autoConfigPackage

> since `1.3.6`

- **Description**：The package path of the automatically generated configuration class --- `AutoMapperConfig`/`AutoMapMapperConfig` --- from the MapStructPlus framework.
- **Type**：`String`
- **Default**：io.github.linpeilie
- **Compile Parameter**：`-Amapstruct.plus.autoConfigPackage`

### autoMapperConfigClassName

> since `1.3.6`

- **Description**：MapStructPlus framework automatically generates the name of the configuration class(transformation between configuration objects)
- **Type**：`String`
- **Default**：AutoMapperConfig
- **Compile Parameter**：`-Amapstruct.plus.autoMapperConfigClassName`

### autoMapMapperConfigClassName

> since `1.3.6`

- **Description**：MapStructPlus framework automatically generates the name of the configuration class(which configures the transformation between the Map and the object)
- **Type**：`String`
- **Default**：AutoMapMapperConfig
- **Compile Parameter**：`-Amapstruct.plus.autoMapMapperConfigClassName`

### typeConversionPolicy

> since `1.4.2`

- **Description**：How lossy (narrowing) conversion, for instance: long to integer should be reported.
- **Type**：`ReportingPolicy`
- **Optional**：
  - `IGNORE`
  - `WARN`
  - `ERROR`
- **Default**：`IGNORE`
- **Compile Parameter**：`-Amapstruct.plus.typeConversionPolicy`

### collectionMappingStrategy

> since `1.4.2`

- **Description**：The strategy to be applied when propagating the value of collection-typed properties. By default, only JavaBeans accessor methods (setters or getters) will be used, but it is also possible to invoke a corresponding adder method for each element of the source collection (e. g. orderDto.
- **Type**：`CollectionMappingStrategy`
- **Optional**：
  - `ACCESSOR_ONLY`
  - `SETTER_PREFERRED`
  - `ADDER_PREFERRED`
  - `TARGET_IMMUTABLE`
- **Default**：`ACCESSOR_ONLY`
- **Compile Parameter**：`-Amapstruct.plus.collectionMappingStrategy`

### nullValueIterableMappingStrategy

> since `1.4.2`

- **Description**：The strategy to be applied when null is passed as source argument value to an IterableMapping. If no strategy is configured, the strategy given via `nullValueMappingStrategy()` will be applied, using `NullValueMappingStrategy`.`RETURN_NULL` by default.
- **Type**：`NullValueMappingStrategy`
- **Optional**：
  - `RETURN_NULL`
  - `RETURN_DEFAULT`
- **Default**：`RETURN_NULL`
- **Compile Parameter**：`-Amapstruct.plus.nullValueIterableMappingStrategy`

### nullValueMapMappingStrategy

> since `1.4.2`

- **Description**：he strategy to be applied when null is passed as source argument value to a MapMapping. If no strategy is configured, the strategy given via `nullValueMappingStrategy()` will be applied, using `NullValueMappingStrategy`.`RETURN_NULL` by default.
- **Type**：`NullValueMappingStrategy`
- **Optional**：
  - `RETURN_NULL`
  - `RETURN_DEFAULT`
- **Default**：`RETURN_NULL`
- **Compile Parameter**：`-Amapstruct.plus.nullValueMapMappingStrategy`

### nullValueCheckStrategy

> since `1.4.2`

- **Description**：Determines when to include a null check on the source property value of a bean mapping.
- **Type**：`NullValueCheckStrategy`
- **Optional**：
  - `ON_IMPLICIT_CONVERSION`
  - `ALWAYS`
- **Default**：`ON_IMPLICIT_CONVERSION`
- **Compile Parameter**：`-Amapstruct.plus.nullValueCheckStrategy`

### mappingControl

> since `1.4.2`

- **Description**：Allows detailed control over the mapping process.
- **Type**：`Class`
- **Default**：`MappingControl.class`

### unexpectedValueMappingException

> since `1.4.2`

- **Description**：Exception that should be thrown by the generated code if no mapping matches for enums. If no exception is configured, IllegalArgumentException will be used by default.
- **Type**：`Class`
- **Default**：`IllegalArgumentException.class`

### suppressTimestampInGenerated

> since `1.4.2`

- **Description**：Flag indicating whether the addition of a time stamp in the @Generated annotation should be suppressed. i. e. not be added. The method overrides the flag set through an annotation processor option.
- **Type**：`boolean`
- **Default**：`false`
- **Compile Parameter**：`-Amapstruct.plus.suppressTimestampInGenerated`