反编译类

package com.hexin.study.interpreter;

import com.hexin.study.util.Log;

import java.io.StringWriter;
import java.util.ArrayList;
import java.util.List;

import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.app.VelocityEngine;

/**
 * @author Administrator
 *
 * 更改所生成类型注释的模板为
 * 窗口 > 首选项 > Java > 代码生成 > 代码和注释
 */
public class ClassTranslation implements Translation{
 
 private String descriptor = null;//说明
 
 private String flag = "false";
 
 private String _extends = "";
 
 private String implement = "";
 
 private String interfaces = "";
 
 private String superClass = "";
 
 private String packageName = null;
 
 private List importList = new ArrayList();
 
 private String accessFlag = null;
 
 private String _class = null;
 
 private String className = null;

 private List fieldList = new ArrayList();

 private List methodList = new ArrayList();
 
 private List table = null;

 /* （非 Javadoc）
  * @see com.hexin.study.interpreter.Translation#translate()
  */
 public void translate(Context c) {
  ClassContext cc = (ClassContext)c;
  if(cc.getMAGIC().equals("CAFEBABE")){
   table = cc.getCONSTANT_POOL();
   translateClass(cc);
  } else{
   descriptor = "不是java class，无法解析";
  }
 }

 /* （非 Javadoc）
  * @see com.hexin.study.interpreter.Translation#print()
  */
 public void print() {
  if(descriptor == null){
   VelocityEngine ve = new VelocityEngine();
   Template t = null;
   try {
    ve.init();
    t = ve.getTemplate("SourceFile.vm");
    VelocityContext context = new VelocityContext();
    context.put("flag",flag);
    context.put("packageName",packageName);
    context.put("importList",importList);
    context.put("accessFlag",accessFlag);
    context.put("extends",_extends);
    context.put("implement",implement);
    context.put("interfaces",interfaces);
    context.put("superClass",superClass);
    context.put("class",_class);
    context.put("className",className);
    context.put("fieldList",fieldList);
    context.put("methodList",methodList);
    StringWriter writer = new StringWriter();
    t.merge(context,writer);
    Log.info(writer.toString()); 
   } catch (Exception e) {
    e.printStackTrace();
   }
  } else{
   Log.info(descriptor);
  }
 }
 
 private void translateClass(ClassContext cc){
  String str = (String)table.get(cc.getTHIS_CLASS()-1);
  int classId = Integer.parseInt(str);
  String tmp = (String)table.get(classId-1);
  tmp = tmp.replaceAll("/",".");
  int i = tmp.lastIndexOf(".");
  packageName = tmp.substring(0,i);
  className = tmp.substring(i+1);
  if(packageName!=null && !packageName.equals(""))
   flag = "true";
  accessFlag = getClassAccess(cc.getACCESS_FLAGS());
  superClass = getSuperClass(cc);
  interfaces = getInterfaces(cc);
  getMethodList(methodList,cc);
 }
 
 private String getClassAccess(short s){
  StringBuffer sb = new StringBuffer();
  short ACC_PUBLIC    = 0x0001;
  short ACC_FINAL     = 0x0010;
  short ACC_SUPER     = 0x0020;
  short ACC_INTERFACE = 0x0200;
  short ACC_ABSTRACT  = 0x0400;
  
  if((s & ACC_PUBLIC) == ACC_PUBLIC)
   sb.append("public");
  if((s & ACC_FINAL) == ACC_FINAL)
   sb.append(" final");
  if((s & ACC_INTERFACE) == ACC_INTERFACE){
   _class = "interface";
  } else if((s & ACC_ABSTRACT) == ACC_ABSTRACT){
   sb.append(" abstract");
   _class = "class";
  }
  return sb.toString();
 }
 
 private String getSuperClass(ClassContext cc){
  StringBuffer sb = new StringBuffer();
  String str = (String)table.get(cc.getSUPER_CLASS()-1);
  int classId = Integer.parseInt(str);
  String tmp = (String)table.get(classId-1);
  tmp = tmp.replaceAll("/",".");
  if(!tmp.trim().equals("java.lang.Object")){
   _extends = "extends";
   int i = tmp.lastIndexOf(".");
   importList.add(tmp.substring(0,i));
   sb.append(" "+tmp.substring(i+1));
  }
  return sb.toString();
 }
 
 private String getInterfaces(ClassContext cc){
  StringBuffer sb = new StringBuffer();
  if(cc.getINTERFACES_COUNT()==0) return "";
  if(_class.equals("interface")) implement = "extends ";
  else  implement = "implements ";
  for(int i=0;i<cc.getINTERFACES_COUNT();i++){
   int index = Integer.parseInt((String)cc.getINTERFACES().get(i));
   int m = Integer.parseInt((String)table.get(index-1));
   String str = (String)table.get(m-1);
   str = str.replaceAll("/",".");
   String tmp = getObject(str);
   sb.append(tmp+",");
  }
  int length = sb.toString().length();
  return sb.toString().substring(0,length-1);
 }
 
 private void getMethodList(List l,ClassContext cc){
  List tmp = cc.getMETHODS();
  int i = tmp.size();
  for(int m=0;m<i;m++){
   MethodNode mn = (MethodNode)tmp.get(m);
   ClassMethod cm = new ClassMethod();
   cm.setAccessFlag(getMethodAccess(mn.getAccessFlags()));
   cm.setName((String)table.get(mn.getNameIndex()-1));
   String str = (String)table.get(mn.getDescriptorIndex()-1);
   parseMethodParamAndType(cm,str);
   l.add(cm);
  }
 }
 
 private void parseMethodParamAndType(ClassMethod cm,String str){
  str = str.replaceAll("/",".");
  int i = str.indexOf(")");
  String tmpType = str.substring(i+1);
  cm.setType(getMethodType(tmpType));
  if(_class.equals("interface")) cm.setBody(";");
  String tmpParam = str.substring(1,i);
  cm.setParam(getMethodParam(tmpParam));
 }
 
 private String getMethodParam(String str){
  if(str.equals("")) return "";
  
  StringBuffer sb = new StringBuffer();
  byte[] b = str.getBytes();
  int count = 0;//记录数组维度
  int object = 0;//记录对象其实位置
  int objectCount = 1;//记录对象个数
  for(int i=0;i<b.length;i++){
   switch(b[i]){
    case 'B':
     sb.append("byte"+getVD(count)+" b,");
     count = 0;
     break;
    case 'C':
     sb.append("char"+getVD(count)+" ch,");
     count = 0;
     break;
    case 'D':
     sb.append("double"+getVD(count)+" d,");
     count = 0;
     break;
    case 'F':
     sb.append("float"+getVD(count)+" f,");
     count = 0;
     break;
    case 'I':
     sb.append("int"+getVD(count)+" i,");
     count = 0;
     break;
    case 'J':
     sb.append("long"+getVD(count)+" l,");
     count = 0;
     break;
    case 'S':
     sb.append("short"+getVD(count)+" s,");
     count = 0;
     break;
    case 'Z':
     sb.append("boolean"+getVD(count)+" bool,");
     count = 0;
     break;
    case 'L':
     object = i+1;
     for(;b[object]!=';';object++);
     String tmp = new String(b,i,object-i+1);
     sb.append(getObjectType(tmp)+getVD(count)+" o"+objectCount+",");
     objectCount += 1;
     count = 0;
     i = object;
     break;
    case '[':
     count++;
     break;
    case 'V':
     return "void";
   }
  }
  int length = sb.toString().length();
  return sb.toString().substring(0,length-1);
 }
 
 private String getVD(int count){//数组维度
  if(count == 0) return "";
  StringBuffer sb = new StringBuffer();
  for(int m=0;m<count;m++)
   sb.append("[]");
  return sb.toString();
 }
 
 private String getMethodType(String str){
  int i = str.lastIndexOf('[');
  int count = i+1;
  String tmp = getVD(count);
  char c = str.charAt(i+1);
  switch(c){
   case 'B': return "byte"+tmp;
   case 'C': return "char"+tmp;
   case 'D': return "double"+tmp;
   case 'F': return "float"+tmp;
   case 'I': return "int"+tmp;
   case 'J': return "long"+tmp;
   case 'S': return "short"+tmp;
   case 'Z': return "boolean"+tmp;
   case 'L': return getObjectType(str)+tmp;
   default: return "void";
  }
 }
 
 private String getObjectType(String str){
  int i = str.indexOf('L');
  str = str.substring(i+1,str.length()-1);//清楚干扰信息"Ljava.lang.String;
  String tmp = getObject(str);
  return tmp;
 }
 
 private String getObject(String str){
  int index = str.lastIndexOf('.');
  String tmp = str.substring(index+1);
  if((str.indexOf("java.lang")==-1)&&!(str.indexOf(packageName+".")!=-1)){
   importList.add(str);
  }
  return tmp;
 }
 
 private String getMethodAccess(short s){
  StringBuffer sb = new StringBuffer();
  short ACC_PUBLIC     = 0x0001;
  short ACC_PRIVATE    = 0x0002;
  short ACC_PROTECTED  = 0x0004;
  short ACC_STATIC     = 0x0008;
  short ACC_FINAL      = 0x0010;
  short ACC_SYNCHRONIZED = 0x0020;
  short ACC_NATIVE  = 0x0100;
  short ACC_ABSTRACT  = 0x0400;
  short ACC_STRICT  = 0x0800;

  if((s & ACC_PUBLIC) == ACC_PUBLIC)
   sb.append("public");
  if((s & ACC_PROTECTED) == ACC_PROTECTED)
   sb.append("protected");
  if((s & ACC_PRIVATE) == ACC_PRIVATE)
   sb.append("private");
  if((s & ACC_FINAL) == ACC_FINAL)
   sb.append(" final");
  if((s & ACC_STATIC) == ACC_STATIC)
   sb.append(" static");
  if((_class.indexOf("interface")==-1) && ((s & ACC_ABSTRACT) == ACC_ABSTRACT))
   sb.append(" abstract");
    
  return sb.toString();
 }