- 依赖
spring5.1.3 自带asm5.0.3，spring4.3.6 自带asm-3.2,还要需要一个jar:asm-commons,和asm版本一致就行
- 测试类
import java.io.File;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
public class Abc<T, U> extends LinkedHashMap<T, U> implements Iterable<T> {
public Abc() {
super();
}
public Iterator iterator2(T var1, U var2) {
return null;
}
public Iterator<T> iterator() {
return null;
}
public Integer compareTo(Integer var1) {
return var1;
}
public T getA(U var1) {
return null;
}
public List<File> get() {
ArrayList arrayList = new ArrayList();
return arrayList;
}
public static void main(String[] var0) {
System.out.println("aaa");
}
}
import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.StringTokenizer;
public class BinaryClassLoader {
private final ArrayList m_bases;
public BinaryClassLoader() {
m_bases = new ArrayList();
}
public void addPaths(String list) {
StringTokenizer tkzr = new StringTokenizer(list, File.pathSeparator);
while (tkzr.hasMoreTokens()) {
File file = new File(tkzr.nextToken());
String spec = null;
if (file.isFile() && file.getName().toLowerCase().endsWith(".jar")) {
spec = "jar:file://" + file.getAbsolutePath() + "!/";
} else if (file.exists()) {
spec = "file://" + file.getAbsolutePath();
if (!spec.endsWith("/")) {
spec += '/';
}
}
if (spec != null) {
m_bases.add(spec);
System.out.println("add loader path:" + spec);
}
}
}
public byte[] getBytes(String name) {
String pname = name.replace('.', '/') + ".class";
for (int i = 0; i < m_bases.size(); i++) {
String base = (String) m_bases.get(i);
try {
URL url = new URL(base + pname);
InputStream is = url.openStream();
// read the entire content into byte array
ByteArrayOutputStream bos = new ByteArrayOutputStream();
byte[] buff = new byte[1024];
int length;
while ((length = is.read(buff)) >= 0) {
bos.write(buff, 0, length);
}
return bos.toByteArray();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (FileNotFoundException e) {
// normal event when not found relative to current base
} catch (IOException e) {
e.printStackTrace();
}
}
throw new IllegalArgumentException("Class not found: " + name);
}
}
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.commons.EmptyVisitor;
public class ShowSignaturesVisitor extends EmptyVisitor {
public void visit(int version, int access, String name, String sig,
String sname, String[] inames) {
System.out.println("Class " + name + " signature:");
System.out.println(" " + sig);
super.visit(version, access, name, sig, sname, inames);
}
public FieldVisitor visitField(int access, String name, String desc,
String sig, Object value) {
System.out.println("Field " + name + " descriptor and signature:");
System.out.println(" " + desc);
System.out.println(" " + sig);
return super.visitField(access, name, desc, sig, value);
}
public MethodVisitor visitMethod(int access, String name, String desc,
String sig, String[] exceptions) {
System.out.println("Method " + name + "() descriptor and signature:");
System.out.println(" " + desc);
System.out.println(" " + sig);
return super.visitMethod(access, name, desc, sig, exceptions);
}
}
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.FieldVisitor;
import org.objectweb.asm.MethodVisitor;
import static org.objectweb.asm.Opcodes.ASM4;
import static org.objectweb.asm.Opcodes.ASM5;
public class ShowSignaturesVisitor extends ClassVisitor {
public ShowSignaturesVisitor() {
super(ASM5);
}
public void visit(int version, int access, String name, String sig,
String sname, String[] inames) {
System.out.println("Class " + name + " signature:");
System.out.println(" " + sig);
super.visit(version, access, name, sig, sname, inames);
}
public FieldVisitor visitField(int access, String name, String desc,
String sig, Object value) {
System.out.println("Field " + name + " descriptor and signature:");
System.out.println(" " + desc);
System.out.println(" " + sig);
return super.visitField(access, name, desc, sig, value);
}
public MethodVisitor visitMethod(int access, String name, String desc,
String sig, String[] exceptions) {
System.out.println("Method " + name + "() descriptor and signature:");
System.out.println(" " + desc);
System.out.println(" " + sig);
return super.visitMethod(access, name, desc, sig, exceptions);
}
}
import org.objectweb.asm.ClassReader;
import java.lang.reflect.Method;
public class PrintSignatures {
public static void main(String[] args) {
// args = new String[]{"com.coding.asm.check.Abc"};
args = new String[]{"Abc"};
System.getProperties().forEach((p,v) ->{
System.out.println(p+":"+v);
});
if (args.length == 1) {
try {
// configure binary class loader from classpaths
BinaryClassLoader loader = new BinaryClassLoader();
loader.addPaths(System.getProperty("java.class.path"));
loader.addPaths(System.getProperty("sun.boot.library.path"));
// analyze the named class 加载类
byte[] bytes = loader.getBytes(args[0]);
ClassReader creader = new ClassReader(bytes);
creader.accept(new ShowSignaturesVisitor(), 1);
Class<?> abc = Class.forName("Abc");
Object o = abc.getDeclaredConstructor(null).newInstance();
Method print = abc.getDeclaredMethod("print", null);
print.invoke(o,null);
} catch (Exception e) {
e.printStackTrace();
}
} else {
System.out.println("Usage: class full name ");
}
}
}
Class Abc signature:
<K:Ljava/lang/Object;V:Ljava/lang/Object;>Ljava/util/LinkedHashMap<TK;TV;>;Ljava/lang/Iterable<TK;>;
Field a descriptor and signature:
I
null
Field b descriptor and signature:
D
null
Field c descriptor and signature:
Ljava/util/Map;
Ljava/util/Map<TK;TV;>;
Method <init>() descriptor and signature:
()V
()V
Method iterator2() descriptor and signature:
(Ljava/lang/Object;Ljava/lang/Object;)Ljava/util/Iterator;
(TK;TV;)Ljava/util/Iterator;
Method iterator() descriptor and signature:
()Ljava/util/Iterator;
()Ljava/util/Iterator<TK;>;
Method compareTo() descriptor and signature:
(Ljava/lang/Integer;)Ljava/lang/Integer;
(Ljava/lang/Integer;)Ljava/lang/Integer;
Method getA() descriptor and signature:
(Ljava/lang/Object;)Ljava/lang/Object;
(TV;)TK;
Method get() descriptor and signature:
()Ljava/util/List;
()Ljava/util/List<Ljava/io/File;>;
Method main() descriptor and signature:
([Ljava/lang/String;)V
([Ljava/lang/String;)V
Method print() descriptor and signature:
()V
()V
Hello ASM!
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