ASM 判定一个类，实现了指定接口

技术支持

ASM 中，ClassReader 类：对已存在的进行解析，并提供获取类信息的方法。

通过 ClassReader ，实现对一个类的解析。

处理流程

依据如下流程，判断出一个类是否实现了某个接口:

循环判断是否实现目标接口
递归判断父接口是否存在目标接口
递归判断父类是否实现目标接口

具体实现

具体实现代码如下：

package utils;import org.objectweb.asm.ClassReader;import java.io.IOException;
import java.util.Set;/*** 判断某类是否实现了指定接口集合** @author pengpj* @date 2018/11/27*/
public class SpecifiedInterfaceImplementionChecked {/*** 判断是否实现了指定接口** @param reader       class reader* @param interfaceSet interface collection* @return check result*/public static boolean hasImplSpecifiedInterfaces(ClassReader reader, Set<String> interfaceSet) {if (isObject(reader.getClassName())) {return false;}try {if (containedTargetInterface(reader.getInterfaces(), interfaceSet)) {return true;} else {ClassReader parent = new ClassReader(reader.getSuperName());return hasImplSpecifiedInterfaces(parent, interfaceSet);}} catch (IOException e) {return false;}}/*** 检查当前类是 Object 类型** @param className class name* @return checked result*/private static boolean isObject(String className) {return "java/lang/Object".equals(className);}/*** 检查接口及其父接口是否实现了目标接口** @param interfaceList 待检查接口* @param interfaceSet  目标接口* @return checked result* @throws IOException exp*/private static boolean containedTargetInterface(String[] interfaceList, Set<String> interfaceSet) throws IOException {for (String inter : interfaceList) {if (interfaceSet.contains(inter)) {return true;} else {ClassReader reader = new ClassReader(inter);if (containedTargetInterface(reader.getInterfaces(), interfaceSet)) {return true;}}}return false;}}

测试用例

部分测试用例如下：

 private static Set<String> set;static {if (set == null) {set = new HashSet<>();}set.add("com/cvte/myou/apm/agent/utils/SpecifiedInterfaceImplCheckedTest$A");}@Testpublic void hasImplSpecifiedInterfacesTest() throws IOException {Assert.assertEquals(true, SpecifiedInterfaceImplChecked.hasImplSpecifiedInterfaces(new ClassReader(B.class.getName()), set));Assert.assertEquals(true, SpecifiedInterfaceImplChecked.hasImplSpecifiedInterfaces(new ClassReader(C.class.getName()), set));}@Testpublic void hasImplSpecifiedInterfacesObjectTest() throws IOException {Assert.assertEquals(false, SpecifiedInterfaceImplChecked.hasImplSpecifiedInterfaces(new ClassReader(Object.class.getName()), set));}@Testpublic void hasImplSpecifiedInterfacesInterfaceTest() throws IOException {Assert.assertEquals(true, SpecifiedInterfaceImplChecked.hasImplSpecifiedInterfaces(new ClassReader(D.class.getName()), set));}interface A {void hello();}class B implements A {@Overridepublic void hello() {}}abstract class C implements A {}interface D extends A {}