我有下一节课：
映射器
public interface DeviceTokensMapper {
DeviceTokensMapper INSTANCE = Mappers.getMapper(DeviceTokensMapper.class);
@Mappings({
@Mapping(source = "tokenName", target = "tokenName"),
@Mapping(source = "userOsType", target = "osType"),
})
DeviceTokensDTO toDeviceTokensDTO(DeviceTokens deviceTokens);
}
实体：
@Entity
public class DeviceTokens {
@Id
@Column(name="token_name", nullable = false)
private String tokenName;
@Column(name = "os", nullable = false)
@Enumerated
private UserOSType userOsType;
public DeviceTokens() {}
public DeviceTokens(String tokenName, UserOSType userOSType) {
this.tokenName = tokenName;
this.userOsType = userOSType;
}
public String getTokenName() {
return tokenName;
}
public void setTokenName(String tokenName) {
this.tokenName = tokenName;
}
public UserOSType getUserOsType() {
return userOsType;
}
public void setUserOsType(UserOSType userOsType) {
this.userOsType = userOsType;
}
}
DTO：
public class DeviceTokensDTO {
private String tokenName;
private UserOSType osType;
public DeviceTokensDTO() {}
public DeviceTokensDTO(String tokenName, UserOSType osType) {
this.tokenName = tokenName;
this.osType = osType;
}
public UserOSType getOsType() {
return osType;
}
public void setOsType(UserOSType osType) {
this.osType = osType;
}
public String getTokenName() {
return tokenName;
}
public void setTokenName(String tokenName) {
this.tokenName = tokenName;
}
}
以及我使用此映射的spring服务类的方法：
@Transactional
public DeviceTokensDTO storeToken(String tokenId, UserOSType userOsType) {
DeviceTokens deviceTokens = new DeviceTokens(tokenId, userOsType);
DeviceTokens newDevice = deviceTokensRepository.save(deviceTokens);
return DeviceTokensMapper.INSTANCE.toDeviceTokensDTO(newDevice);
}
当我运行上述方法时，我看到下一个异常：
错误 [dispatcherServlet]:? - servlet [dispatcherServlet] 在路径 [] 的上下文中的 Servlet.service() 引发异常 [处理程序处理失败；嵌套异常是 java.lang.ExceptionInInitializerError]，其根本原因是 java.lang.ClassNotFoundException: dto.DeviceTokensMapperImpl
那么为什么mapper需要实现类呢？可以请人建议吗？谢谢。