程序包 cn.taketoday.bytecode

类 BytecodeCompiler

java.lang.Object

cn.taketoday.bytecode.BytecodeCompiler

直接已知子类:

SpelCompiler

public abstract class BytecodeCompiler
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 2021/11/29 11:23

作者:

Harry Yang

嵌套类概要

嵌套类

修饰符和类型	类	说明
private static class	BytecodeCompiler.ChildClassLoader	A ChildClassLoader will load the generated compiled classes.

字段概要

字段

修饰符和类型	字段	说明
protected BytecodeCompiler.ChildClassLoader	childClassLoader
private static final int	CLASSES_DEFINED_LIMIT
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

限定符	构造器	说明
protected	BytecodeCompiler(ClassLoader classloader)

方法概要

修饰符和类型	方法	说明
static <T> Class<T>	compile(String className, Class<?> neighbor, ClassLoader loader, ProtectionDomain domain, byte[] classFile)	Loads a class file by a given class loader.
protected final <T> Class<T>	loadClass(String name, byte[] classFile)	Load a class.
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

CLASSES_DEFINED_LIMIT

private static final int CLASSES_DEFINED_LIMIT

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

childClassLoader

protected volatile BytecodeCompiler.ChildClassLoader childClassLoader

构造器详细资料

BytecodeCompiler

protected BytecodeCompiler(@Nullable
 ClassLoader classloader)

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)

loadClass

protected final <T> Class<T> loadClass(String name,
 byte[] classFile)

Load a class. Makes sure the classloaders aren't used too much because they anchor compiled classes in memory and prevent GC. If you have expressions continually recompiling over time then by replacing the classloader periodically at least some of the older variants can be garbage collected.

参数:

name - the name of the class

classFile - the bytecode for the class

返回:

the Class object for the compiled expression

compile

public static <T> Class<T> compile(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)