重构LambdaUtil，强化原有的SerializedLambda缓存为自定义LambdaInfo，该类额外存储了lambda反射类，且可以获取到lambda中使用的外部变量参数;额外在ReflectUtil新增了部分函数，用于获取描述符

2025-04-19 03:01:48 +08:00 · 2022-06-04 00:22:27 +08:00 · 2022-06-04 00:22:27 +08:00 · c4a2be8120
commit c4a2be8120
parent 41bd03fa25
4 changed files with 313 additions and 122 deletions
--- a/hutool-core/src/main/java/cn/hutool/core/lang/func/LambdaInfo.java
+++ b/hutool-core/src/main/java/cn/hutool/core/lang/func/LambdaInfo.java
@ -0,0 +1,78 @@
+package cn.hutool.core.lang.func;
+
+import cn.hutool.core.classloader.ClassLoaderUtil;
+import cn.hutool.core.reflect.FieldUtil;
+import cn.hutool.core.text.StrUtil;
+
+import java.lang.invoke.SerializedLambda;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Executable;
+import java.lang.reflect.Method;
+import java.lang.reflect.Type;
+
+/**
+ * 存放lambda信息
+ *
+ * @author VampireAchao
+ */
+public class LambdaInfo {
+
+	private Type instantiatedType;
+	private final Type[] parameterTypes;
+	private final Type returnType;
+	private final String name;
+	private final Executable executable;
+	private final Class<?> clazz;
+	private final SerializedLambda lambda;
+
+	public LambdaInfo(Executable executable, SerializedLambda lambda) {
+		if (executable instanceof Method) {
+			Method method = (Method) executable;
+			this.parameterTypes = method.getGenericParameterTypes();
+			this.returnType = method.getGenericReturnType();
+			this.name = method.getName();
+		} else if (executable instanceof Constructor) {
+			Constructor<?> constructor = (Constructor<?>) executable;
+			this.parameterTypes = constructor.getGenericParameterTypes();
+			this.returnType = constructor.getDeclaringClass();
+			this.name = constructor.getName();
+		} else {
+			throw new IllegalArgumentException("Unsupported executable type: " + executable.getClass());
+		}
+		int index = lambda.getInstantiatedMethodType().indexOf(";)");
+		if (index > -1) {
+			this.instantiatedType = ClassLoaderUtil.loadClass(StrUtil.sub(lambda.getInstantiatedMethodType(), 2, index));
+		}
+		this.clazz = (Class<?>) FieldUtil.getFieldValue(executable, "clazz");
+		this.executable = executable;
+		this.lambda = lambda;
+	}
+
+	public Type getInstantiatedType() {
+		return instantiatedType;
+	}
+
+	public Type[] getParameterTypes() {
+		return parameterTypes;
+	}
+
+	public Type getReturnType() {
+		return returnType;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public Executable getExecutable() {
+		return executable;
+	}
+
+	public Class<?> getClazz() {
+		return clazz;
+	}
+
+	public SerializedLambda getLambda() {
+		return lambda;
+	}
+}
--- a/hutool-core/src/main/java/cn/hutool/core/lang/func/LambdaUtil.java
+++ b/hutool-core/src/main/java/cn/hutool/core/lang/func/LambdaUtil.java
@ -2,13 +2,18 @@ package cn.hutool.core.lang.func;

 import cn.hutool.core.bean.BeanUtil;
 import cn.hutool.core.classloader.ClassLoaderUtil;
+import cn.hutool.core.exceptions.UtilException;
+import cn.hutool.core.lang.Opt;
 import cn.hutool.core.map.WeakConcurrentMap;
 import cn.hutool.core.reflect.MethodUtil;
-import cn.hutool.core.text.StrUtil;
+import cn.hutool.core.reflect.ReflectUtil;

 import java.io.Serializable;
-import java.lang.invoke.MethodHandleInfo;
 import java.lang.invoke.SerializedLambda;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
+import java.util.Objects;

 /**
 * Lambda相关工具类
@ -18,7 +23,7 @@ import java.lang.invoke.SerializedLambda;
 */
 public class LambdaUtil {

-	private static final WeakConcurrentMap<String, SerializedLambda> cache = new WeakConcurrentMap<>();
+	private static final WeakConcurrentMap<String, LambdaInfo> CACHE = new WeakConcurrentMap<>();

 	/**
 	 * 通过对象的方法或类的静态方法引用，获取lambda实现类
@ -50,39 +55,49 @@ public class LambdaUtil {
 	 * @param func lambda
 	 * @param <R>  类型
 	 * @return lambda实现类
-	 * @throws IllegalArgumentException 如果是不支持的方法引用，抛出该异常，见{@link LambdaUtil#checkLambdaTypeCanGetClass}
-	 * @since 5.8.0
 	 * @author VampireAchao
 	 */
-	public static <R> Class<R> getRealClass(final Func0<?> func) {
-		final SerializedLambda lambda = resolve(func);
-		checkLambdaTypeCanGetClass(lambda.getImplMethodKind());
-		return ClassLoaderUtil.loadClass(lambda.getImplClass());
+	@SuppressWarnings("unchecked")
+	public static <R> Class<R> getRealClass(final Serializable func) {
+		LambdaInfo lambdaInfo = resolve(func);
+		return (Class<R>) Opt.of(lambdaInfo).map(LambdaInfo::getInstantiatedType).orElseGet(lambdaInfo::getClazz);
 	}

 	/**
 	 * 解析lambda表达式,加了缓存。
 	 * 该缓存可能会在任意不定的时间被清除
 	 *
-	 * @param <T>  Lambda类型
 	 * @param func 需要解析的 lambda 对象（无参方法）
 	 * @return 返回解析后的结果
 	 */
-	public static <T> SerializedLambda resolve(final Func1<T, ?> func) {
-		return _resolve(func);
+	public static LambdaInfo resolve(final Serializable func) {
+		return CACHE.computeIfAbsent(func.getClass().getName(), (key) -> {
+			final SerializedLambda serializedLambda = _resolve(func);
+			final String methodName = serializedLambda.getImplMethodName();
+			final Class<?> implClass;
+			ClassLoaderUtil.loadClass(serializedLambda.getImplClass().replace("/", "."), true);
+			try {
+				implClass = Class.forName(serializedLambda.getImplClass().replace("/", "."), true, Thread.currentThread().getContextClassLoader());
+			} catch (ClassNotFoundException e) {
+				throw new UtilException(e);
 			}
-
-	/**
-	 * 解析lambda表达式,加了缓存。
-	 * 该缓存可能会在任意不定的时间被清除
-	 *
-	 * @param <R>  Lambda返回类型
-	 * @param func 需要解析的 lambda 对象（无参方法）
-	 * @return 返回解析后的结果
-	 * @since 5.7.23
-	 */
-	public static <R> SerializedLambda resolve(final Func0<R> func) {
-		return _resolve(func);
+			if ("<init>".equals(methodName)) {
+				for (Constructor<?> constructor : implClass.getDeclaredConstructors()) {
+					if (ReflectUtil.getDescriptor(constructor).equals(serializedLambda.getImplMethodSignature())) {
+						return new LambdaInfo(constructor, serializedLambda);
+					}
+				}
+			} else {
+				Method[] methods = MethodUtil.getMethods(implClass);
+				for (Method method : methods) {
+					if (method.getName().equals(methodName)
+							&& ReflectUtil.getDescriptor(method).equals(serializedLambda.getImplMethodSignature())) {
+						return new LambdaInfo(method, serializedLambda);
+					}
+				}
+			}
+			throw new IllegalStateException("No lambda method found.");
+		});
 	}

 	/**
@ -93,7 +108,7 @@ public class LambdaUtil {
 	 * @return 函数名称
 	 */
 	public static <P> String getMethodName(final Func1<P, ?> func) {
-		return resolve(func).getImplMethodName();
+		return resolve(func).getName();
 	}

 	/**
@ -105,36 +120,7 @@ public class LambdaUtil {
 	 * @since 5.7.23
 	 */
 	public static <R> String getMethodName(final Func0<R> func) {
-		return resolve(func).getImplMethodName();
-	}
-
-	/**
-	 * 通过对象的方法或类的静态方法引用，然后根据{@link SerializedLambda#getInstantiatedMethodType()}获取lambda实现类<br>
-	 * 传入lambda有参数且含有返回值的情况能够匹配到此方法：
-	 * <ul>
-	 * <li>引用特定类型的任意对象的实例方法：<pre>{@code
-	 * Class<MyTeacher> functionClass = LambdaUtil.getRealClass(MyTeacher::getAge);
-	 * Assert.assertEquals(MyTeacher.class, functionClass);
-	 * }</pre></li>
-	 * <li>引用静态带参方法：<pre>{@code
-	 * Class<MyTeacher> staticFunctionClass = LambdaUtil.getRealClass(MyTeacher::takeAgeBy);
-	 * Assert.assertEquals(MyTeacher.class, staticFunctionClass);
-	 * }</pre></li>
-	 * </ul>
-	 *
-	 * @param func lambda
-	 * @param <P>  方法调用方类型
-	 * @param <R>  返回值类型
-	 * @return lambda实现类
-	 * @throws IllegalArgumentException 如果是不支持的方法引用，抛出该异常，见{@link LambdaUtil#checkLambdaTypeCanGetClass}
-	 * @since 5.8.0
-	 * @author VampireAchao
-	 */
-	public static <P, R> Class<P> getRealClass(final Func1<P, R> func) {
-		final SerializedLambda lambda = resolve(func);
-		checkLambdaTypeCanGetClass(lambda.getImplMethodKind());
-		final String instantiatedMethodType = lambda.getInstantiatedMethodType();
-		return ClassLoaderUtil.loadClass(StrUtil.sub(instantiatedMethodType, 2, StrUtil.indexOf(instantiatedMethodType, ';')));
+		return resolve(func).getName();
 	}

 	/**
@ -176,18 +162,6 @@ public class LambdaUtil {
 	}

 	//region Private methods
-	/**
-	 * 检查是否为支持的类型
-	 *
-	 * @param implMethodKind 支持的lambda类型
-	 * @throws IllegalArgumentException 如果是不支持的方法引用，抛出该异常
-	 */
-	private static void checkLambdaTypeCanGetClass(final int implMethodKind) {
-		if (implMethodKind != MethodHandleInfo.REF_invokeVirtual &&
-				implMethodKind != MethodHandleInfo.REF_invokeStatic) {
-			throw new IllegalArgumentException("该lambda不是合适的方法引用");
-		}
-	}

 	/**
 	 * 解析lambda表达式,加了缓存。
@ -202,7 +176,21 @@ public class LambdaUtil {
 	 * @return 返回解析后的结果
 	 */
 	private static SerializedLambda _resolve(final Serializable func) {
-		return cache.computeIfAbsent(func.getClass().getName(), (key) -> MethodUtil.invoke(func, "writeReplace"));
+		if (func instanceof SerializedLambda) {
+			return (SerializedLambda) func;
+		}
+		if (func instanceof Proxy) {
+			throw new UtilException("not support proxy, just for now");
+		}
+		final Class<? extends Serializable> clazz = func.getClass();
+		if (!clazz.isSynthetic()) {
+			throw new UtilException("Not a lambda expression: " + clazz.getName());
+		}
+		final Object serLambda = MethodUtil.invoke(func, "writeReplace");
+		if (Objects.nonNull(serLambda) && serLambda instanceof SerializedLambda) {
+			return (SerializedLambda) serLambda;
+		}
+		throw new UtilException("writeReplace result value is not java.lang.invoke.SerializedLambda");
 	}
 	//endregion
 }
--- a/hutool-core/src/main/java/cn/hutool/core/reflect/ReflectUtil.java
+++ b/hutool-core/src/main/java/cn/hutool/core/reflect/ReflectUtil.java
@ -1,6 +1,9 @@
 package cn.hutool.core.reflect;

 import java.lang.reflect.AccessibleObject;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Executable;
+import java.lang.reflect.Method;

 /**
 * 反射工具类
@ -24,4 +27,105 @@ public class ReflectUtil {
 		}
 		return accessibleObject;
 	}
+
+	/**
+	 * 获取描述符
+	 *
+	 * @param executable 可执行的反射对象
+	 * @return 描述符
+	 */
+	public static String getDescriptor(Executable executable) {
+		StringBuilder stringBuilder = new StringBuilder();
+		stringBuilder.append('(');
+		Class<?>[] parameters = executable.getParameterTypes();
+		for (Class<?> parameter : parameters) {
+			appendDescriptor(parameter, stringBuilder);
+		}
+		if (executable instanceof Method) {
+			Method method = (Method) executable;
+			stringBuilder.append(')');
+			appendDescriptor(method.getReturnType(), stringBuilder);
+			return stringBuilder.toString();
+		} else if (executable instanceof Constructor) {
+			return stringBuilder.append(")V").toString();
+		}
+		throw new IllegalArgumentException("Unknown Executable: " + executable);
+	}
+
+	private static void appendDescriptor(Class<?> clazz, StringBuilder stringBuilder) {
+		Class<?> currentClass;
+		for (currentClass = clazz;
+			 currentClass.isArray();
+			 currentClass = currentClass.getComponentType()) {
+			stringBuilder.append('[');
+		}
+		if (currentClass.isPrimitive()) {
+			final char descriptor;
+			// see sun.invoke.util.Wrapper
+			// These must be in the order defined for widening primitive conversions in JLS 5.1.2
+			if (currentClass == boolean.class) {
+				descriptor = 'Z';
+			} else if (currentClass == byte.class) {
+				descriptor = 'B';
+			} else if (currentClass == short.class) {
+				descriptor = 'S';
+			} else if (currentClass == char.class) {
+				descriptor = 'C';
+			} else if (currentClass == int.class) {
+				descriptor = 'I';
+			} else if (currentClass == long.class) {
+				descriptor = 'J';
+			} else if (currentClass == float.class) {
+				descriptor = 'F';
+			} else if (currentClass == double.class) {
+				descriptor = 'D';
+			} else if (currentClass == Object.class) {
+				descriptor = 'L';
+			} else if (currentClass == void.class) {
+				// VOID must be the last type, since it is "assignable" from any other type:
+				descriptor = 'V';
+			} else {
+				throw new AssertionError();
+			}
+			stringBuilder.append(descriptor);
+		} else {
+			stringBuilder.append('L').append(currentClass.getName().replace('.', '/')).append(';');
+		}
+
+	}
+
+	private static char getDescriptorChar(Class<?> currentClass) {
+		if (currentClass == Boolean.class || currentClass == boolean.class) {
+			return 'Z';
+		}
+		if (currentClass == Byte.class || currentClass == byte.class) {
+			return 'B';
+		}
+		if (currentClass == Short.class || currentClass == short.class) {
+			return 'S';
+		}
+		if (currentClass == Character.class || currentClass == char.class) {
+			return 'C';
+		}
+		if (currentClass == Integer.class || currentClass == int.class) {
+			return 'I';
+		}
+		if (currentClass == Long.class || currentClass == long.class) {
+			return 'J';
+		}
+		if (currentClass == Float.class || currentClass == float.class) {
+			return 'F';
+		}
+		if (currentClass == Double.class || currentClass == double.class) {
+			return 'D';
+		}
+		if (currentClass == Object.class) {
+			return 'L';
+		}
+		if (currentClass == Void.class || currentClass == void.class) {
+			return 'V';
+		}
+		throw new AssertionError();
+	}
+
 }
--- a/hutool-core/src/test/java/cn/hutool/core/lang/func/LambdaUtilTest.java
+++ b/hutool-core/src/test/java/cn/hutool/core/lang/func/LambdaUtilTest.java
@ -1,14 +1,15 @@
 package cn.hutool.core.lang.func;

-import org.junit.Assert;
-import org.junit.Test;
-
 import lombok.AllArgsConstructor;
 import lombok.Data;
 import lombok.EqualsAndHashCode;
+import org.junit.Assert;
+import org.junit.Test;

-import java.lang.invoke.MethodHandleInfo;
+import java.lang.reflect.Array;
+import java.util.stream.Stream;

+@SuppressWarnings("unchecked")
 public class LambdaUtilTest {

 	@Test
@ -25,60 +26,80 @@ public class LambdaUtilTest {

 	@Test
 	public void resolveTest() {
+		Stream.<Runnable>of(() -> {
 			// 引用构造函数
-		Assert.assertEquals(MethodHandleInfo.REF_newInvokeSpecial,
-				LambdaUtil.resolve(MyTeacher::new).getImplMethodKind());
-		// 数组构造函数引用
-		Assert.assertEquals(MethodHandleInfo.REF_invokeStatic,
-				LambdaUtil.resolve(MyTeacher[]::new).getImplMethodKind());
+			Func0<MyTeacher> lambda = MyTeacher::new;
+			LambdaInfo lambdaInfo = LambdaUtil.resolve(lambda);
+			Assert.assertEquals(0, lambdaInfo.getParameterTypes().length);
+			Assert.assertEquals(MyTeacher.class, lambdaInfo.getReturnType());
+		}, () -> {
+			// 数组构造函数引用(此处数组构造参数)
+			Func1<Integer, MyTeacher[]> lambda = MyTeacher[]::new;
+			LambdaInfo lambdaInfo = LambdaUtil.resolve(lambda);
+			Assert.assertEquals(int.class, lambdaInfo.getParameterTypes()[0]);
+			Assert.assertEquals(MyTeacher.class, ((Class<Array>) lambdaInfo.getReturnType()).getComponentType());
+		}, () -> {
 			// 引用静态方法
-		Assert.assertEquals(MethodHandleInfo.REF_invokeStatic,
-				LambdaUtil.resolve(MyTeacher::takeAge).getImplMethodKind());
+			Func0<String> noArgsStaticMethod = MyTeacher::takeAge;
+			LambdaInfo lambdaInfo = LambdaUtil.resolve(noArgsStaticMethod);
+			Assert.assertEquals(String.class, lambdaInfo.getReturnType());
+		}, () -> {
 			// 引用特定对象的实例方法
-		Assert.assertEquals(MethodHandleInfo.REF_invokeVirtual,
-				LambdaUtil.resolve(new MyTeacher()::getAge).getImplMethodKind());
+			Func0<String> instantiated = new MyTeacher()::getAge;
+			LambdaInfo lambdaInfo = LambdaUtil.resolve(instantiated);
+			Assert.assertEquals(String.class, lambdaInfo.getReturnType());
+		}, () -> {
 			// 引用特定类型的任意对象的实例方法
-		Assert.assertEquals(MethodHandleInfo.REF_invokeVirtual,
-				LambdaUtil.resolve(MyTeacher::getAge).getImplMethodKind());
+			Func1<MyTeacher, String> annoInstantiated = MyTeacher::getAge;
+			LambdaInfo lambdaInfo = LambdaUtil.resolve(annoInstantiated);
+			Assert.assertEquals(String.class, lambdaInfo.getReturnType());
+		}).forEach(Runnable::run);
 	}

-
 	@Test
 	public void getRealClassTest() {
-		// 引用特定类型的任意对象的实例方法
-		final Class<MyTeacher> functionClass = LambdaUtil.getRealClass(MyTeacher::getAge);
-		Assert.assertEquals(MyTeacher.class, functionClass);
-		// 枚举测试，不会导致类型擦除
-		final Class<LambdaKindEnum> enumFunctionClass = LambdaUtil.getRealClass(LambdaKindEnum::ordinal);
-		Assert.assertEquals(LambdaKindEnum.class, enumFunctionClass);
-		// 调用父类方法，能获取到正确的子类类型
-		final Class<MyTeacher> superFunctionClass = LambdaUtil.getRealClass(MyTeacher::getId);
-		Assert.assertEquals(MyTeacher.class, superFunctionClass);
-
 		final MyTeacher myTeacher = new MyTeacher();
+		Stream.<Runnable>of(() -> {
+			// 引用特定类型的任意对象的实例方法
+			final Func1<MyTeacher, String> lambda = MyTeacher::getAge;
+			Assert.assertEquals(MyTeacher.class, LambdaUtil.getRealClass(lambda));
+		}, () -> {
+			// 枚举测试，不会导致类型擦除
+			final Func1<LambdaKindEnum, Integer> lambda = LambdaKindEnum::ordinal;
+			Assert.assertEquals(LambdaKindEnum.class, LambdaUtil.getRealClass(lambda));
+		}, () -> {
+			// 调用父类方法，能获取到正确的子类类型
+			final Func1<MyTeacher, ?> lambda = MyTeacher::getId;
+			Assert.assertEquals(MyTeacher.class, LambdaUtil.getRealClass(lambda));
+		}, () -> {
 			// 引用特定对象的实例方法
-		final Class<MyTeacher> supplierClass = LambdaUtil.getRealClass(myTeacher::getAge);
-		Assert.assertEquals(MyTeacher.class, supplierClass);
+			Func0<String> lambda = myTeacher::getAge;
+			Assert.assertEquals(MyTeacher.class, LambdaUtil.getRealClass(lambda));
+		}, () -> {
 			// 枚举测试，只能获取到枚举类型
-		final Class<Enum<?>> enumSupplierClass = LambdaUtil.getRealClass(LambdaKindEnum.REF_NONE::ordinal);
-		Assert.assertEquals(Enum.class, enumSupplierClass);
+			Func0<Integer> lambda = LambdaKindEnum.REF_NONE::ordinal;
+			Assert.assertEquals(Enum.class, LambdaUtil.getRealClass(lambda));
+		}, () -> {
 			// 调用父类方法，只能获取到父类类型
-		final Class<Entity<?>> superSupplierClass = LambdaUtil.getRealClass(myTeacher::getId);
-		Assert.assertEquals(Entity.class, superSupplierClass);
-
+			VoidFunc0 lambda = myTeacher::getId;
+			Assert.assertEquals(Entity.class, LambdaUtil.getRealClass(lambda));
+		}, () -> {
 			// 引用静态带参方法，能够获取到正确的参数类型
-		final Class<MyTeacher> staticFunctionClass = LambdaUtil.getRealClass(MyTeacher::takeAgeBy);
-		Assert.assertEquals(MyTeacher.class, staticFunctionClass);
+			Func1<MyTeacher, String> lambda = MyTeacher::takeAgeBy;
+			Assert.assertEquals(MyTeacher.class, LambdaUtil.getRealClass(lambda));
+		}, () -> {
 			// 引用父类静态带参方法，只能获取到父类类型
-		final Class<Entity<?>> staticSuperFunctionClass = LambdaUtil.getRealClass(MyTeacher::takeId);
-		Assert.assertEquals(Entity.class, staticSuperFunctionClass);
-
+			Func0<?> lambda = MyTeacher::takeId;
+			Assert.assertEquals(Entity.class, LambdaUtil.getRealClass(lambda));
+		}, () -> {
 			// 引用静态无参方法，能够获取到正确的类型
-		final Class<MyTeacher> staticSupplierClass = LambdaUtil.getRealClass(MyTeacher::takeAge);
-		Assert.assertEquals(MyTeacher.class, staticSupplierClass);
+			Func0<String> lambda = MyTeacher::takeAge;
+			Assert.assertEquals(MyTeacher.class, LambdaUtil.getRealClass(lambda));
+		}, () -> {
 			// 引用父类静态无参方法，能够获取到正确的参数类型
-		final Class<MyTeacher> staticSuperSupplierClass = LambdaUtil.getRealClass(MyTeacher::takeIdBy);
-		Assert.assertEquals(MyTeacher.class, staticSuperSupplierClass);
+			Func1<MyTeacher, ?> lambda = MyTeacher::takeIdBy;
+			Assert.assertEquals(MyTeacher.class, LambdaUtil.getRealClass(lambda));
+		}).forEach(Runnable::run);
 	}

 	@Data