利用Javassist获取Java类中的方法参数名、参数类型、方法访问类型

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我是靠谱客的博主激情机器猫，这篇文章主要介绍利用Javassist获取Java类中的方法参数名、参数类型、方法访问类型，现在分享给大家，希望可以做个参考。

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http://www.csg.is.titech.ac.jp/~chiba/javassist/

复制代码

package com.vl;
import java.lang.reflect.Method;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtMethod;
import javassist.Modifier;
import javassist.NotFoundException;
import javassist.bytecode.AccessFlag;
import javassist.bytecode.CodeAttribute;
import javassist.bytecode.LocalVariableAttribute;
import javassist.bytecode.MethodInfo;
import com.vl.app.PTZ;
import com.vl.app.StreamsUtil;
import com.vl.sql.UserDAO;
public class VLInterface {
public static void main(String[] args) throws NotFoundException {
ClassPool pool = ClassPool.getDefault();
Class[] cs = new Class[] { PTZ.class, UserDAO.class ,StreamsUtil.class};
String[] prefixStrings = new String[] { "ptz", "user" ,"streamsutil"};
for (int i = 0; i < cs.length; i++) {
CtClass ctClass;
Class clz = cs[i];
ctClass = pool.get(clz.getName());
Method[] methods = clz.getDeclaredMethods();
for (Method m : methods) {
String name = m.getName();
CtMethod cm = ctClass.getDeclaredMethod(name);
MethodInfo methodInfo = cm.getMethodInfo();
Class[] parameterTypes = m.getParameterTypes();
CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
LocalVariableAttribute attr = (LocalVariableAttribute) codeAttribute
.getAttribute(LocalVariableAttribute.tag);
if (attr == null) {
// exception
}
if(cm.getMethodInfo().getAccessFlags()!=AccessFlag.PUBLIC)continue;
//System.out.println();
String[] paramNames = new String[cm.getParameterTypes().length];
int pos = Modifier.isStatic(cm.getModifiers()) ? 0 : 1;
for (int j = 0; j < paramNames.length; j++)
paramNames[j] = attr.variableName(j + pos);
// paramNames即参数名
System.out.printf(""%s.%s":rntReturn:%st(Parameters ",
prefixStrings[i], name, m.getReturnType().getSimpleName());
for (int i1 = 0; i1 < paramNames.length; i1++) {
System.out.printf("%d:[%s %s] ", i1+1, parameterTypes[i1]
.getSimpleName(), paramNames[i1]);
}
// for (Class class1 : parameterTypes) {
// System.out.printf("[%s],", class1.getName());
// }
System.out.println(")rn");
}
}
}
}

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package com.vl;
import java.lang.reflect.Method;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtMethod;
import javassist.Modifier;
import javassist.NotFoundException;
import javassist.bytecode.AccessFlag;
import javassist.bytecode.CodeAttribute;
import javassist.bytecode.LocalVariableAttribute;
import javassist.bytecode.MethodInfo;
import com.vl.app.PTZ;
import com.vl.app.StreamsUtil;
import com.vl.sql.UserDAO;
public class VLInterface {
public static void main(String[] args) throws NotFoundException {
ClassPool pool = ClassPool.getDefault();
Class[] cs = new Class[] { PTZ.class, UserDAO.class ,StreamsUtil.class};
String[] prefixStrings = new String[] { "ptz", "user" ,"streamsutil"};
for (int i = 0; i < cs.length; i++) {
CtClass ctClass;
Class clz = cs[i];
ctClass = pool.get(clz.getName());
Method[] methods = clz.getDeclaredMethods();
for (Method m : methods) {
String name = m.getName();
CtMethod cm = ctClass.getDeclaredMethod(name);
MethodInfo methodInfo = cm.getMethodInfo();
Class[] parameterTypes = m.getParameterTypes();
CodeAttribute codeAttribute = methodInfo.getCodeAttribute();
LocalVariableAttribute attr = (LocalVariableAttribute) codeAttribute
.getAttribute(LocalVariableAttribute.tag);
if (attr == null) {
// exception
}
if(cm.getMethodInfo().getAccessFlags()!=AccessFlag.PUBLIC)continue;
//System.out.println();
String[] paramNames = new String[cm.getParameterTypes().length];
int pos = Modifier.isStatic(cm.getModifiers()) ? 0 : 1;
for (int j = 0; j < paramNames.length; j++)
paramNames[j] = attr.variableName(j + pos);
// paramNames即参数名
System.out.printf(""%s.%s":rntReturn:%st(Parameters ",
prefixStrings[i], name, m.getReturnType().getSimpleName());
for (int i1 = 0; i1 < paramNames.length; i1++) {
System.out.printf("%d:[%s %s] ", i1+1, parameterTypes[i1]
.getSimpleName(), paramNames[i1]);
}
// for (Class class1 : parameterTypes) {
// System.out.printf("[%s],", class1.getName());
// }
System.out.println(")rn");
}
}
}
}