MAPtruct - 将字段值映射到属性
问题描述:
我有要求将源类中的字段值映射到字段属性的位置。我能够使用Mapstruct使用@Mapper注释的 '表达' 参数做MAPtruct - 将字段值映射到属性
源类:
public class ClassA {
public ClassA() {
}
private String name;
private String address;
private ArrayList<RequestFilter> filter;
public ArrayList<RequestFilter> getFilter() {
return filter;
}
public void setFilter(ArrayList<RequestFilter> filter) {
this.filter = filter;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
目标类:
public class ClassATransform {
public ClassATransform() {
}
private String name;
private String id;
private String address;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
}
我mapstruct映射器看起来是这样的:
@Mapper(imports=RequestFilter.class)
public interface ClassAMapper {
ClassAMapper INSTANCE = Mappers.getMapper(ClassAMapper.class);
@Mappings({
@Mapping(target = "name", source = "name"),
@Mapping(target= "address", source = "address"),
@Mapping(target = "id", expression="java(req.getFilter().get(req.getFilter().indexOf(new RequestFilter(\"id\"))).filterValue)")
})
ClassATransform classAToDTO(ClassA req);
}
RequestFilter.java:
public class RequestFilter {
public RequestFilter() {
}
public RequestFilter(String filterName) {
this.filterName = filterName;
}
public String filterName;
public String filterValue;
public String filterOperator;
public String joinOperator;
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((filterName == null) ? 0 : filterName.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
RequestFilter other = (RequestFilter) obj;
if (filterName == null) {
if (other.filterName != null)
return false;
} else if (!filterName.equals(other.filterName))
return false;
return true;
}
}
有没有其他方法可以在不使用“表达式”的情况下进行映射?
答
你可以提供一个自定义的方法,将其映射为您:
@Mapper
public interface ClassAMapper {
ClassAMapper INSTANCE = Mappers.getMapper(ClassAMapper.class);
@Mappings({
@Mapping(target = "id", source = "req")
})
ClassATransform classAToDTO(ClassA req);
default String mapToid(ClassA req) {
// null checks
return reg.getFilter()
.stream()
.filter(filter -> filter.filterName.equals("id"))
.findAny()
.orElse(null);
}
}
顺便说一句。 和target
相同的映射不需要,因为MapStruct会自动执行该操作。
感谢您的回答。那么如果在数组中有'n'RequestFilter,我需要'n''default'方法吗? – ssdimmanuel
如果你有'n'RequestFilters,我建议你使用'@ AfterMapping',你可以在那里传入源和目标并在那里做映射。这对性能会更好,并且您不需要使用限定符来定义n'@ Mapping'就可以使其工作 – Filip