org.javaweb.utils.ASMClassUtils.java Source code

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Here is the source code for org.javaweb.utils.ASMClassUtils.java

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/*
 * Copyright yz 2016-01-14  Email:admin@javaweb.org.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.javaweb.utils;

import org.objectweb.asm.*;
import org.objectweb.asm.tree.AnnotationNode;
import org.springframework.asm.Opcodes;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * Created by yz on 2017/1/22.
 *
 * @author yz
 */
public class ASMClassUtils {

    public byte[] createClassWriter(byte[] classfileBuffer, Class<?> targetClass) {
        ClassReader cr = new ClassReader(classfileBuffer);

        if (!ClassUtils.isInterface(cr)) {
            ClassWriter cw = new ClassWriter(cr, ClassWriter.COMPUTE_MAXS);
            try {
                ClassVisitor classVisitor = (ClassVisitor) targetClass
                        .getConstructor(Integer.class, ClassWriter.class).newInstance(Opcodes.ASM5, cw);
                cr.accept(classVisitor, ClassReader.EXPAND_FRAMES);

                return cw.toByteArray();
            } catch (Throwable t) {
                t.printStackTrace();
            }
        }

        return classfileBuffer;
    }

    /**
     * ASM??,??????class
     *
     * @param classFileBuffer ?
     * @return
     */
    public Map<String, List<AnnotationNode>> getClassAnnotation(byte[] classFileBuffer) {
        final Map<String, List<AnnotationNode>> annotationNodeMap = new LinkedHashMap<String, List<AnnotationNode>>();
        final List<AnnotationNode> classAnnotationNodeList = new ArrayList<AnnotationNode>();
        final List<AnnotationNode> methodAnnotationNodeList = new ArrayList<AnnotationNode>();
        final List<AnnotationNode> fieldAnnotationNodeList = new ArrayList<AnnotationNode>();
        final ClassReader cr = new ClassReader(classFileBuffer);

        if (!ClassUtils.isInterface(cr)) {

            ClassWriter cw = new ClassWriter(cr, ClassWriter.COMPUTE_MAXS);

            cr.accept(new ClassVisitor(Opcodes.ASM5, cw) {
                @Override
                public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
                    AnnotationNode an = new AnnotationNode(desc);
                    classAnnotationNodeList.add(an);

                    return an;
                }

                @Override
                public MethodVisitor visitMethod(int access, String methodName, String argTypeDesc,
                        String signature, String[] exceptions) {
                    final MethodVisitor mv = super.visitMethod(access, methodName, argTypeDesc, signature,
                            exceptions);
                    return new MethodVisitor(Opcodes.ASM5, mv) {

                        @Override
                        public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
                            AnnotationNode an = new AnnotationNode(desc);
                            methodAnnotationNodeList.add(an);

                            return an;
                        }
                    };
                }

                @Override
                public FieldVisitor visitField(int access, String methodName, String argTypeDesc, String signature,
                        final Object value) {
                    final FieldVisitor fv = super.visitField(access, methodName, argTypeDesc, signature, value);
                    return new FieldVisitor(Opcodes.ASM5, fv) {
                        @Override
                        public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
                            AnnotationNode an = new AnnotationNode(desc);
                            fieldAnnotationNodeList.add(an);

                            return an;
                        }
                    };
                }
            }, ClassReader.EXPAND_FRAMES);
        }

        annotationNodeMap.put("class", classAnnotationNodeList);
        annotationNodeMap.put("method", methodAnnotationNodeList);
        annotationNodeMap.put("field", fieldAnnotationNodeList);

        return annotationNodeMap;
    }

}