程序包 cn.taketoday.util

类 DefineClassHelper

java.lang.Object

cn.taketoday.util.DefineClassHelper

public class DefineClassHelper
extends Object

Helper class for invoking ClassLoader.defineClass(String, byte[], int, int).

This first tries to use java.lang.invoke.MethodHandle to load a class. Otherwise, or if neighbor is null, this tries to use sun.misc.Unsafe to load a class. Then it tries to use a protected method in java.lang.ClassLoader via PrivilegedAction. Since the latter approach is not available any longer by default in Java 9 or later, the JVM argument --add-opens java.base/java.lang=ALL-UNNAMED must be given to the JVM.

 --add-opens java.base/java.lang=ALL-UNNAMED
 --add-opens java.base/java.util=ALL-UNNAMED
 --add-opens java.base/java.lang.reflect=ALL-UNNAMED
 

从以下版本开始:

4.0

作者:

TODAY 2021/11/8 9:44

字段概要

字段

修饰符和类型	字段	说明
private static final Method	classLoaderDefineClassMethod
private static BiConsumer<String,byte[]>	generatedClassHandler
private static Consumer<Class<?>>	loadedClassHandler
private static final ProtectionDomain	PROTECTION_DOMAIN
private static final Throwable	THROWABLE

构造器概要

构造器

构造器	说明
DefineClassHelper()

方法概要

修饰符和类型	方法	说明
static Class<?>	defineClass(Class<?> neighbor, byte[] bcode)	Loads a class file by java.lang.invoke.MethodHandles.Lookup.
static Class<?>	defineClass(String className, byte[] b, ClassLoader loader)
static Class<?>	defineClass(String className, byte[] b, ClassLoader loader, ProtectionDomain protectionDomain)
static Class<?>	defineClass(String className, Class<?> neighbor, ClassLoader loader, ProtectionDomain domain, byte[] classFile)	Loads a class file by a given class loader.
static Class<?>	loadClass(String className, ClassLoader classLoader)
private static CodeGenerationException	newException(String className, Throwable ex)
static void	setGeneratedClassHandler(BiConsumer<String,byte[]> handler)
static void	setLoadedClassHandler(Consumer<Class<?>> handler)

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

字段详细资料

classLoaderDefineClassMethod

@Nullable
private static final Method classLoaderDefineClassMethod

THROWABLE

@Nullable
private static final Throwable THROWABLE

PROTECTION_DOMAIN

@Nullable
private static final ProtectionDomain PROTECTION_DOMAIN

loadedClassHandler

@Nullable
private static Consumer<Class<?>> loadedClassHandler

generatedClassHandler

@Nullable
private static BiConsumer<String,byte[]> generatedClassHandler

构造器详细资料

DefineClassHelper

public DefineClassHelper()

方法详细资料

setGeneratedClassHandler

public static void setGeneratedClassHandler(@Nullable
 BiConsumer<String,byte[]> handler)

setLoadedClassHandler

public static void setLoadedClassHandler(@Nullable
 Consumer<Class<?>> handler)

defineClass

public static Class<?> defineClass(Class<?> neighbor,
 byte[] bcode)
                            throws ReflectionException

Loads a class file by java.lang.invoke.MethodHandles.Lookup. It is obtained by using neighbor.

参数:

neighbor - a class belonging to the same package that the loaded class belogns to.

bcode - the bytecode.

抛出:

ReflectionException

defineClass

public static Class<?> defineClass(String className,
 byte[] b,
 ClassLoader loader)
                            throws CodeGenerationException

抛出:

CodeGenerationException

defineClass

public static Class<?> defineClass(String className,
 byte[] b,
 ClassLoader loader,
 ProtectionDomain protectionDomain)
                            throws CodeGenerationException

抛出:

CodeGenerationException

defineClass

public static Class<?> defineClass(String className,
 @Nullable
 Class<?> neighbor,
 ClassLoader loader,
 @Nullable
 ProtectionDomain domain,
 byte[] classFile)
                            throws CodeGenerationException

Loads a class file by a given class loader.

This first tries to use java.lang.invoke.MethodHandle to load a class. Otherwise, or if neighbor is null, this tries to use sun.misc.Unsafe to load a class. Then it tries to use a protected method in java.lang.ClassLoader via PrivilegedAction. Since the latter approach is not available any longer by default in Java 9 or later, the JVM argument --add-opens java.base/java.lang=ALL-UNNAMED must be given to the JVM.

 --add-opens java.base/java.lang=ALL-UNNAMED
 --add-opens java.base/java.util=ALL-UNNAMED
 --add-opens java.base/java.lang.reflect=ALL-UNNAMED
 

参数:

className - the name of the loaded class.

neighbor - the class contained in the same package as the loaded class.

loader - the class loader. It can be null if neighbor is not null and the JVM is Java 11 or later.

domain - if it is null, a default domain is used.

classFile - the bytecode for the loaded class.

抛出:

CodeGenerationException

loadClass

public static Class<?> loadClass(String className,
 ClassLoader classLoader)
                          throws ClassNotFoundException

抛出:

ClassNotFoundException

newException

private static CodeGenerationException newException(String className,
 Throwable ex)