知行合一，止于至善
千里之行，始于足下；合抱之木，生于毫末；九层之台，起于累土Lambda 获取setter对应的BiConsumer 函数对象
12月 28, 2022 |
Nix.Huang
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public static <T, U> BiConsumer<T, U> getSetter(Class<T> clazz, String fieldName, Class<U> fieldType) throws Throwable { MethodHandles.Lookup caller = MethodHandles.lookup(); MethodType setter = MethodType.methodType(void.class, fieldType); MethodHandle target = caller.findVirtual(clazz, computeSetterName(fieldName), setter); CallSite site = LambdaMetafactory.metafactory( caller, "accept", //interfaceMethodName MethodType.methodType(BiConsumer.class), //factoryType //interfaceMethodType，泛型一律使用Object.class MethodType.methodType(void.class, Object.class, Object.class), target, //implementation target.type() //dynamicMethodType, 泛型对应的具体类型 ); MethodHandle factory = site.getTarget(); return (BiConsumer<T, U>) factory.invokeExact(); } public static String computeSetterName(String fieldName) { return "set" + fieldName.substring(0, 1).toUpperCase() + fieldName.substring(1); } |
当获取的函数对象是泛型时，那么interfaceMethodType和dynamicMethodType的类型是不同的。
Posted in: java基础
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