java - 当我将 Java 版本升级到 openJDK 11 时，加载模型映射器配置时出现 nullpointerException

Question

将 Java 版本升级到 openJDK 11 后，modelMapper 配置未加载，出现 NullPointerException。

NullPointerException issue is not resolved even after upgrading modelMapper version to 2.3.2

错误日志:

1) 配置映射失败

堆栈跟踪:

at org.modelmapper.internal.Errors.throwConfigurationExceptionIfErrorsExist(Errors.java:241)
    at org.modelmapper.internal.ExplicitMappingBuilder.build(ExplicitMappingBuilder.java:244)
    at org.modelmapper.internal.ExplicitMappingBuilder.build(ExplicitMappingBuilder.java:96)
    at org.modelmapper.internal.TypeMapImpl.addMappings(TypeMapImpl.java:92)
    at org.modelmapper.internal.TypeMapStore.getOrCreate(TypeMapStore.java:124)
    at org.modelmapper.ModelMapper.addMappings(ModelMapper.java:113)
    ...
Caused by: java.lang.NullPointerException
    at org.modelmapper.internal.ExplicitMappingBuilder$ExplicitMappingInterceptor.access$000(ExplicitMappingBuilder.java:304)
    at org.modelmapper.internal.ExplicitMappingBuilder.createAccessorProxies(ExplicitMappingBuilder.java:287)
    at org.modelmapper.internal.ExplicitMappingBuilder.createProxies(ExplicitMappingBuilder.java:277)
    at org.modelmapper.internal.ExplicitMappingBuilder.visitPropertyMap(ExplicitMappingBuilder.java:266)
    at org.modelmapper.PropertyMap.configure(PropertyMap.java:386)
    at jdk.internal.reflect.GeneratedMethodAccessor16.invoke(Unknown Source)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.modelmapper.internal.ExplicitMappingBuilder.build(ExplicitMappingBuilder.java:227)
    ... 6 more

Answer 1

在 ByteBuddy 内部抛出一个导致问题的异常，我将进一步调查它是否可能是 ModelMapper 中的错误。

无论如何，请在 http://modelmapper.org/user-manual/property-mapping/ 查看 Java 8 选项卡，您当前的代码似乎使用的是旧文档。

ModelMapper mm = new ModelMapper();

TypeMap<A, B> typeMap = mm.createTypeMap(A.class, B.class);
typeMap.addMappings(mapper -> {
    mapper.map(A::getDate, B::setTest);
    ... // Other mappings
});

这可以立即转换 Date -> Long 而无需任何其他配置。如果你想进一步配置它，你总是可以像这样创建自定义转换器:

Converter<Date, Long> dateToLong = new AbstractConverter<Date, Long>() {
    @Override
    protected Long convert(Date source) {
        System.out.println("converting: " + source + " to " + source.getTime());
        return source.getTime();
    }
};

typeMap.addMappings(mapper -> mapper.using(dateToLong).map(A::getDate, B::setTest));