open jdk javap对于class文件的解析分析
来源：互联网 发布：中国人有钱知乎 编辑：程序博客网 时间：2024/05/22 16:40
package sun.tools.javap;import java.util.*;import java.io.*;/** * Central data repository of the Java Disassembler. * Stores all the information in java class file. * * @author Sucheta Dambalkar (Adopted code from jdis) */public class ClassData implements RuntimeConstants { private int magic; private int minor_version; private int major_version; private int cpool_count; private Object cpool[]; private int access; private int this_class = 0;; private int super_class; private int interfaces_count; private int[] interfaces = new int[0];; private int fields_count; private FieldData[] fields; private int methods_count; private MethodData[] methods; private InnerClassData[] innerClasses; private int attributes_count; private AttrData[] attrs; private String classname; private String superclassname; private int source_cpx=0; private byte tags[]; private Hashtable indexHashAscii = new Hashtable(); private String pkgPrefix=""; private int pkgPrefixLen=0; /** * Read classfile to disassemble. */ public ClassData(InputStream infile){ try{ this.read(new DataInputStream(infile)); }catch (FileNotFoundException ee) { error("cant read file"); }catch (Error ee) { ee.printStackTrace(); error("fatal error"); } catch (Exception ee) { ee.printStackTrace(); error("fatal exception"); } } /** * Reads and stores class file information. */ public void read(DataInputStream in) throws IOException { // Read the header magic = in.readInt();//先读取魔法数，值为0xcafebabe，以此来区分是否为java class文件 if (magic != JAVA_MAGIC) { throw new ClassFormatError("wrong magic: " + toHex(magic) + ", expected " + toHex(JAVA_MAGIC)); } minor_version = in.readShort(); major_version = in.readShort(); if (major_version != JAVA_VERSION) {//class文件版本号，现在我的jdk版本里面配置的是45，JAVA_MINOR_VERSION为3 } // Read the constant pool readCP(in);//读取常量池 access = in.readUnsignedShort();//访问标识字段，标识是否为public，final，abstract等很多访问控制 this_class = in.readUnsignedShort();//类的常量池索引项 super_class = in.readUnsignedShort();//父类的常量池索引项 //Read interfaces. interfaces_count = in.readUnsignedShort();//接口个数 if(interfaces_count > 0){ interfaces = new int[interfaces_count]; } for (int i = 0; i < interfaces_count; i++) { interfaces[i]=in.readShort();//每个接口的常量池索引项 } // Read the fields readFields(in);//读取类字段 // Read the methods readMethods(in);//读取类的方法信息 // Read the attributes attributes_count = in.readUnsignedShort(); //读取类的属性信息 attrs=new AttrData[attributes_count]; for (int k = 0; k < attributes_count; k++) { int name_cpx=in.readUnsignedShort(); if (getTag(name_cpx)==CONSTANT_UTF8 && getString(name_cpx).equals("SourceFile") ){ if (in.readInt()!=2) throw new ClassFormatError("invalid attr length"); source_cpx=in.readUnsignedShort(); AttrData attr=new AttrData(this); attr.read(name_cpx); attrs[k]=attr; } else if (getTag(name_cpx)==CONSTANT_UTF8 && getString(name_cpx).equals("InnerClasses") ){ int length=in.readInt(); int num=in.readUnsignedShort(); if (2+num*8 != length) throw new ClassFormatError("invalid attr length"); innerClasses=new InnerClassData[num]; for (int j = 0; j < num; j++) { InnerClassData innerClass=new InnerClassData(this); innerClass.read(in); innerClasses[j]=innerClass; } AttrData attr=new AttrData(this); attr.read(name_cpx); attrs[k]=attr; } else { AttrData attr=new AttrData(this); attr.read(name_cpx, in); attrs[k]=attr; } } in.close(); } // end ClassData.read() /** * Reads and stores constant pool info. */ void readCP(DataInputStream in) throws IOException { cpool_count = in.readUnsignedShort(); tags = new byte[cpool_count]; cpool = new Object[cpool_count]; for (int i = 1; i < cpool_count; i++) { byte tag = in.readByte(); switch(tags[i] = tag) { case CONSTANT_UTF8: String str=in.readUTF(); indexHashAscii.put(cpool[i] = str, new Integer(i)); break; case CONSTANT_INTEGER: cpool[i] = new Integer(in.readInt()); break; case CONSTANT_FLOAT: cpool[i] = new Float(in.readFloat()); break; case CONSTANT_LONG: cpool[i++] = new Long(in.readLong()); break; case CONSTANT_DOUBLE: cpool[i++] = new Double(in.readDouble()); break; case CONSTANT_CLASS: case CONSTANT_STRING: cpool[i] = new CPX(in.readUnsignedShort()); break; case CONSTANT_FIELD: case CONSTANT_METHOD: case CONSTANT_INTERFACEMETHOD: case CONSTANT_NAMEANDTYPE: cpool[i] = new CPX2(in.readUnsignedShort(), in.readUnsignedShort()); break; case 0: default: throw new ClassFormatError("invalid constant type: " + (int)tags[i]); } } } /** * Reads and strores field info. */ protected void readFields(DataInputStream in) throws IOException { int fields_count = in.readUnsignedShort(); fields=new FieldData[fields_count]; for (int k = 0; k < fields_count; k++) { FieldData field=new FieldData(this); field.read(in); fields[k]=field; } } /** * Reads and strores Method info. */ protected void readMethods(DataInputStream in) throws IOException { int methods_count = in.readUnsignedShort(); methods=new MethodData[methods_count]; for (int k = 0; k < methods_count ; k++) { MethodData method=new MethodData(this); method.read(in); methods[k]=method; } } /** * get a string */ public String getString(int n) { return (n == 0) ? null : (String)cpool[n]; } /** * get the type of constant given an index */ public byte getTag(int n) { try{ return tags[n]; } catch (ArrayIndexOutOfBoundsException e) { return (byte)100; } } static final String hexString="0123456789ABCDEF"; public static char hexTable[]=hexString.toCharArray(); static String toHex(long val, int width) { StringBuffer s = new StringBuffer(); for (int i=width-1; i>=0; i--) s.append(hexTable[((int)(val>>(4*i)))&0xF]); return "0x"+s.toString(); } static String toHex(long val) { int width; for (width=16; width>0; width--) { if ((val>>(width-1)*4)!=0) break; } return toHex(val, width); } static String toHex(int val) { int width; for (width=8; width>0; width--) { if ((val>>(width-1)*4)!=0) break; } return toHex(val, width); } public void error(String msg) { System.err.println("ERROR:" +msg); } /** * Returns the name of this class. */ public String getClassName() { String res=null; if (this_class==0) { return res; } int tcpx; try { if (tags[this_class]!=CONSTANT_CLASS) { return res; //"<CP["+cpx+"] is not a Class> "; } tcpx=((CPX)cpool[this_class]).cpx; } catch (ArrayIndexOutOfBoundsException e) { return res; // "#"+cpx+"// invalid constant pool index"; } catch (Throwable e) { return res; // "#"+cpx+"// ERROR IN DISASSEMBLER"; } try { return (String)(cpool[tcpx]); } catch (ArrayIndexOutOfBoundsException e) { return res; // "class #"+scpx+"// invalid constant pool index"; } catch (ClassCastException e) { return res; // "class #"+scpx+"// invalid constant pool reference"; } catch (Throwable e) { return res; // "#"+cpx+"// ERROR IN DISASSEMBLER"; } } /** * Returns the name of class at perticular index. */ public String getClassName(int cpx) { String res="#"+cpx; if (cpx==0) { return res; } int scpx; try { if (tags[cpx]!=CONSTANT_CLASS) { return res; //"<CP["+cpx+"] is not a Class> "; } scpx=((CPX)cpool[cpx]).cpx; } catch (ArrayIndexOutOfBoundsException e) { return res; // "#"+cpx+"// invalid constant pool index"; } catch (Throwable e) { return res; // "#"+cpx+"// ERROR IN DISASSEMBLER"; } res="#"+scpx; try { return (String)(cpool[scpx]); } catch (ArrayIndexOutOfBoundsException e) { return res; // "class #"+scpx+"// invalid constant pool index"; } catch (ClassCastException e) { return res; // "class #"+scpx+"// invalid constant pool reference"; } catch (Throwable e) { return res; // "#"+cpx+"// ERROR IN DISASSEMBLER"; } } /** * Returns true if it is a class */ public boolean isClass() { if((access & ACC_INTERFACE) == 0) return true; return false; } /** * Returns true if it is a interface. */ public boolean isInterface(){ if((access & ACC_INTERFACE) != 0) return true; return false; } /** * Returns true if this member is public, false otherwise. */ public boolean isPublic(){ return (access & ACC_PUBLIC) != 0; } /** * Returns the access of this class or interface. */ public String[] getAccess(){ Vector v = new Vector(); if ((access & ACC_PUBLIC) !=0) v.addElement("public"); if ((access & ACC_FINAL) !=0) v.addElement("final"); if ((access & ACC_ABSTRACT) !=0) v.addElement("abstract"); String[] accflags = new String[v.size()]; v.copyInto(accflags); return accflags; } /** * Returns list of innerclasses. */ public InnerClassData[] getInnerClasses(){ return innerClasses; } /** * Returns list of attributes. */ public AttrData[] getAttributes(){ return attrs; } /** * Returns true if superbit is set. */ public boolean isSuperSet(){ if ((access & ACC_SUPER) !=0) return true; return false; } /** * Returns super class name. */ public String getSuperClassName(){ String res=null; if (super_class==0) { return res; } int scpx; try { if (tags[super_class]!=CONSTANT_CLASS) { return res; //"<CP["+cpx+"] is not a Class> "; } scpx=((CPX)cpool[super_class]).cpx; } catch (ArrayIndexOutOfBoundsException e) { return res; // "#"+cpx+"// invalid constant pool index"; } catch (Throwable e) { return res; // "#"+cpx+"// ERROR IN DISASSEMBLER"; } try { return (String)(cpool[scpx]); } catch (ArrayIndexOutOfBoundsException e) { return res; // "class #"+scpx+"// invalid constant pool index"; } catch (ClassCastException e) { return res; // "class #"+scpx+"// invalid constant pool reference"; } catch (Throwable e) { return res; // "#"+cpx+"// ERROR IN DISASSEMBLER"; } } /** * Returns list of super interfaces. */ public String[] getSuperInterfaces(){ String interfacenames[] = new String[interfaces.length]; int interfacecpx = -1; for(int i = 0; i < interfaces.length; i++){ interfacecpx=((CPX)cpool[interfaces[i]]).cpx; interfacenames[i] = (String)(cpool[interfacecpx]); } return interfacenames; } /** * Returns string at prticular constant pool index. */ public String getStringValue(int cpoolx) { try { return ((String)cpool[cpoolx]); } catch (ArrayIndexOutOfBoundsException e) { return "//invalid constant pool index:"+cpoolx; } catch (ClassCastException e) { return "//invalid constant pool ref:"+cpoolx; } } /** * Returns list of field info. */ public FieldData[] getFields(){ return fields; } /** * Returns list of method info. */ public MethodData[] getMethods(){ return methods; } /** * Returns constant pool entry at that index. */ public CPX2 getCpoolEntry(int cpx){ return ((CPX2)(cpool[cpx])); } public Object getCpoolEntryobj(int cpx){ return (cpool[cpx]); } /** * Returns index of this class. */ public int getthis_cpx(){ return this_class; } public String TagString (int tag) { String res=Tables.tagName(tag); if (res==null) return "BOGUS_TAG:"+tag; return res; } /** * Returns string at that index. */ public String StringValue(int cpx) { if (cpx==0) return "#0"; int tag; Object x; String suffix=""; try { tag=tags[cpx]; x=cpool[cpx]; } catch (IndexOutOfBoundsException e) { return "<Incorrect CP index:"+cpx+">"; } if (x==null) return "<NULL>"; switch (tag) { case CONSTANT_UTF8: { StringBuffer sb=new StringBuffer(); String s=(String)x; for (int k=0; k<s.length(); k++) { char c=s.charAt(k); switch (c) { case '\t': sb.append('\\').append('t'); break; case '\n': sb.append('\\').append('n'); break; case '\r': sb.append('\\').append('r'); break; case '\"': sb.append('\\').append('\"'); break; default: sb.append(c); } } return sb.toString(); } case CONSTANT_DOUBLE: { Double d=(Double)x; String sd=d.toString(); return sd+"d"; } case CONSTANT_FLOAT: { Float f=(Float)x; String sf=(f).toString(); return sf+"f"; } case CONSTANT_LONG: { Long ln = (Long)x; return ln.toString()+'l'; } case CONSTANT_INTEGER: { Integer in = (Integer)x; return in.toString(); } case CONSTANT_CLASS: return javaName(getClassName(cpx)); case CONSTANT_STRING: return StringValue(((CPX)x).cpx); case CONSTANT_FIELD: case CONSTANT_METHOD: case CONSTANT_INTERFACEMETHOD: //return getShortClassName(((CPX2)x).cpx1)+"."+StringValue(((CPX2)x).cpx2); return javaName(getClassName(((CPX2)x).cpx1))+"."+StringValue(((CPX2)x).cpx2); case CONSTANT_NAMEANDTYPE: return getName(((CPX2)x).cpx1)+":"+StringValue(((CPX2)x).cpx2); default: return "UnknownTag"; //TBD } } /** * Returns resolved java type name. */ public String javaName(String name) { if( name==null) return "null"; int len=name.length(); if (len==0) return "\"\""; int cc='/'; fullname: { // xxx/yyy/zzz int cp; for (int k=0; k<len; k += Character.charCount(cp)) { cp=name.codePointAt(k); if (cc=='/') { if (!Character.isJavaIdentifierStart(cp)) break fullname; } else if (cp!='/') { if (!Character.isJavaIdentifierPart(cp)) break fullname; } cc=cp; } return name; } return "\""+name+"\""; } public String getName(int cpx) { String res; try { return javaName((String)cpool[cpx]); //.replace('/','.'); } catch (ArrayIndexOutOfBoundsException e) { return "<invalid constant pool index:"+cpx+">"; } catch (ClassCastException e) { return "<invalid constant pool ref:"+cpx+">"; } } /** * Returns unqualified class name. */ public String getShortClassName(int cpx) { String classname=javaName(getClassName(cpx)); pkgPrefixLen=classname.lastIndexOf("/")+1; if (pkgPrefixLen!=0) { pkgPrefix=classname.substring(0,pkgPrefixLen); if (classname.startsWith(pkgPrefix)) { return classname.substring(pkgPrefixLen); } } return classname; } /** * Returns source file name. */ public String getSourceName(){ return getName(source_cpx); } /** * Returns package name. */ public String getPkgName(){ String classname=getClassName(this_class); pkgPrefixLen=classname.lastIndexOf("/")+1; if (pkgPrefixLen!=0) { pkgPrefix=classname.substring(0,pkgPrefixLen); return("package "+pkgPrefix.substring(0,pkgPrefixLen-1)+";\n"); }else return null; } /** * Returns total constant pool entry count. */ public int getCpoolCount(){ return cpool_count; } public String StringTag(int cpx) { byte tag=0; String str=null; try { if (cpx==0) throw new IndexOutOfBoundsException(); tag=tags[cpx]; return TagString(tag); } catch (IndexOutOfBoundsException e) { str="Incorrect CP index:"+cpx; } return str; } /** * Returns minor version of class file. */ public int getMinor_version(){ return minor_version; } /** * Returns major version of class file. */ public int getMajor_version(){ return major_version; } public static void main(String[] args) throws FileNotFoundException{ System.out.println(new ClassData(new FileInputStream(new File("E:\\logs\\Example.class")))); }}读取类的field信息的类：package sun.tools.javap;import java.util.*;import java.io.*;/** * Strores field data informastion. * * @author Sucheta Dambalkar (Adopted code from jdis) */public class FieldData implements RuntimeConstants { ClassData cls; int access; int name_index; int descriptor_index; int attributes_count; int value_cpx=0; boolean isSynthetic=false; boolean isDeprecated=false; Vector attrs; public FieldData(ClassData cls){ this.cls=cls; } /** * Read and store field info. */ public void read(DataInputStream in) throws IOException { access = in.readUnsignedShort(); name_index = in.readUnsignedShort(); descriptor_index = in.readUnsignedShort(); // Read the attributes int attributes_count = in.readUnsignedShort(); attrs=new Vector(attributes_count); for (int i = 0; i < attributes_count; i++) { int attr_name_index=in.readUnsignedShort(); if (cls.getTag(attr_name_index)!=CONSTANT_UTF8) continue; String attr_name=cls.getString(attr_name_index); if (attr_name.equals("ConstantValue")){ if (in.readInt()!=2) throw new ClassFormatError("invalid ConstantValue attr length"); value_cpx=in.readUnsignedShort(); AttrData attr=new AttrData(cls); attr.read(attr_name_index); attrs.addElement(attr); } else if (attr_name.equals("Synthetic")){ if (in.readInt()!=0) throw new ClassFormatError("invalid Synthetic attr length"); isSynthetic=true; AttrData attr=new AttrData(cls); attr.read(attr_name_index); attrs.addElement(attr); } else if (attr_name.equals("Deprecated")){ if (in.readInt()!=0) throw new ClassFormatError("invalid Synthetic attr length"); isDeprecated = true; AttrData attr=new AttrData(cls); attr.read(attr_name_index); attrs.addElement(attr); } else { AttrData attr=new AttrData(cls); attr.read(attr_name_index, in); attrs.addElement(attr); } } } // end read /** * Returns access of a field. */ public String[] getAccess(){ Vector v = new Vector(); if ((access & ACC_PUBLIC) !=0) v.addElement("public"); if ((access & ACC_PRIVATE) !=0) v.addElement("private"); if ((access & ACC_PROTECTED) !=0) v.addElement("protected"); if ((access & ACC_STATIC) !=0) v.addElement("static"); if ((access & ACC_FINAL) !=0) v.addElement("final"); if ((access & ACC_VOLATILE) !=0) v.addElement("volatile"); if ((access & ACC_TRANSIENT) !=0) v.addElement("transient"); String[] accflags = new String[v.size()]; v.copyInto(accflags); return accflags; } /** * Returns name of a field. */ public String getName(){ return cls.getStringValue(name_index); } /** * Returns internal signature of a field */ public String getInternalSig(){ return cls.getStringValue(descriptor_index); } /** * Returns java type signature of a field. */ public String getType(){ return new TypeSignature(getInternalSig()).getFieldType(); } /** * Returns true if field is synthetic. */ public boolean isSynthetic(){ return isSynthetic; } /** * Returns true if field is deprecated. */ public boolean isDeprecated(){ return isDeprecated; } /** * Returns index of constant value in cpool. */ public int getConstantValueIndex(){ return (value_cpx); } /** * Returns list of attributes of field. */ public Vector getAttributes(){ return attrs; }}读取类的方法
import java.util.*;import java.io.*;import static sun.tools.javap.RuntimeConstants.*;/** * Strores method data informastion. * * @author Sucheta Dambalkar (Adopted code from jdis) */public class MethodData { ClassData cls; int access; int name_index; int descriptor_index; int attributes_count; byte[] code; Vector exception_table = new Vector(0); Vector lin_num_tb = new Vector(0); Vector loc_var_tb = new Vector(0); StackMapTableData[] stackMapTable; StackMapData[] stackMap; int[] exc_index_table=null; Vector attrs=new Vector(0); Vector code_attrs=new Vector(0); int max_stack, max_locals; boolean isSynthetic=false; boolean isDeprecated=false; public MethodData(ClassData cls){ this.cls=cls; } /** * Read method info. */ public void read(DataInputStream in) throws IOException { access = in.readUnsignedShort(); name_index=in.readUnsignedShort(); descriptor_index =in.readUnsignedShort(); int attributes_count = in.readUnsignedShort(); for (int i = 0; i < attributes_count; i++) { int attr_name_index=in.readUnsignedShort(); readAttr: { if (cls.getTag(attr_name_index)==CONSTANT_UTF8) { String attr_name=cls.getString(attr_name_index); if ( attr_name.equals("Code")){ readCode (in); AttrData attr=new AttrData(cls); attr.read(attr_name_index); attrs.addElement(attr); break readAttr; } else if ( attr_name.equals("Exceptions")){ readExceptions(in); AttrData attr=new AttrData(cls); attr.read(attr_name_index); attrs.addElement(attr); break readAttr; } else if (attr_name.equals("Synthetic")){ if (in.readInt()!=0) throw new ClassFormatError("invalid Synthetic attr length"); isSynthetic=true; AttrData attr=new AttrData(cls); attr.read(attr_name_index); attrs.addElement(attr); break readAttr; } else if (attr_name.equals("Deprecated")){ if (in.readInt()!=0) throw new ClassFormatError("invalid Synthetic attr length"); isDeprecated = true; AttrData attr=new AttrData(cls); attr.read(attr_name_index); attrs.addElement(attr); break readAttr; } } AttrData attr=new AttrData(cls); attr.read(attr_name_index, in); attrs.addElement(attr); } } } /** * Read code attribute info. */ public void readCode(DataInputStream in) throws IOException { int attr_length = in.readInt(); max_stack=in.readUnsignedShort(); max_locals=in.readUnsignedShort(); int codelen=in.readInt(); code=new byte[codelen]; int totalread = 0; while(totalread < codelen){ totalread += in.read(code, totalread, codelen-totalread); } // in.read(code, 0, codelen); int clen = 0; readExceptionTable(in); int code_attributes_count = in.readUnsignedShort(); for (int k = 0 ; k < code_attributes_count ; k++) { int table_name_index=in.readUnsignedShort(); int table_name_tag=cls.getTag(table_name_index); AttrData attr=new AttrData(cls); if (table_name_tag==CONSTANT_UTF8) { String table_name_tstr=cls.getString(table_name_index); if (table_name_tstr.equals("LineNumberTable")) { readLineNumTable(in); attr.read(table_name_index); } else if (table_name_tstr.equals("LocalVariableTable")) { readLocVarTable(in); attr.read(table_name_index); } else if (table_name_tstr.equals("StackMapTable")) { readStackMapTable(in); attr.read(table_name_index); } else if (table_name_tstr.equals("StackMap")) { readStackMap(in); attr.read(table_name_index); } else { attr.read(table_name_index, in); } code_attrs.addElement(attr); continue; } attr.read(table_name_index, in); code_attrs.addElement(attr); } } /** * Read exception table info. */ void readExceptionTable (DataInputStream in) throws IOException { int exception_table_len=in.readUnsignedShort(); exception_table=new Vector(exception_table_len); for (int l = 0; l < exception_table_len; l++) { exception_table.addElement(new TrapData(in, l)); } } /** * Read LineNumberTable attribute info. */ void readLineNumTable (DataInputStream in) throws IOException { int attr_len = in.readInt(); // attr_length int lin_num_tb_len = in.readUnsignedShort(); lin_num_tb=new Vector(lin_num_tb_len); for (int l = 0; l < lin_num_tb_len; l++) { lin_num_tb.addElement(new LineNumData(in)); } } /** * Read LocalVariableTable attribute info. */ void readLocVarTable (DataInputStream in) throws IOException { int attr_len=in.readInt(); // attr_length int loc_var_tb_len = in.readUnsignedShort(); loc_var_tb = new Vector(loc_var_tb_len); for (int l = 0; l < loc_var_tb_len; l++) { loc_var_tb.addElement(new LocVarData(in)); } } /** * Read Exception attribute info. */ public void readExceptions(DataInputStream in) throws IOException { int attr_len=in.readInt(); // attr_length in prog int num_exceptions = in.readUnsignedShort(); exc_index_table=new int[num_exceptions]; for (int l = 0; l < num_exceptions; l++) { int exc=in.readShort(); exc_index_table[l]=exc; } } /** * Read StackMapTable attribute info. */ void readStackMapTable(DataInputStream in) throws IOException { int attr_len = in.readInt(); //attr_length int stack_map_tb_len = in.readUnsignedShort(); stackMapTable = new StackMapTableData[stack_map_tb_len]; for (int i=0; i<stack_map_tb_len; i++) { stackMapTable[i] = StackMapTableData.getInstance(in, this); } } /** * Read StackMap attribute info. */ void readStackMap(DataInputStream in) throws IOException { int attr_len = in.readInt(); //attr_length int stack_map_len = in.readUnsignedShort(); stackMap = new StackMapData[stack_map_len]; for (int i = 0; i<stack_map_len; i++) { stackMap[i] = new StackMapData(in, this); } } /** * Return access of the method. */ public String[] getAccess(){ Vector v = new Vector(); if ((access & ACC_PUBLIC) !=0) v.addElement("public"); if ((access & ACC_PRIVATE) !=0) v.addElement("private"); if ((access & ACC_PROTECTED) !=0) v.addElement("protected"); if ((access & ACC_STATIC) !=0) v.addElement("static"); if ((access & ACC_FINAL) !=0) v.addElement("final"); if ((access & ACC_SYNCHRONIZED) !=0) v.addElement("synchronized"); if ((access & ACC_NATIVE) !=0) v.addElement("native"); if ((access & ACC_ABSTRACT) !=0) v.addElement("abstract"); if ((access & ACC_STRICT) !=0) v.addElement("strictfp"); String[] accflags = new String[v.size()]; v.copyInto(accflags); return accflags; } /** * Return name of the method. */ public String getName(){ return cls.getStringValue(name_index); } /** * Return internal siganature of the method. */ public String getInternalSig(){ return cls.getStringValue(descriptor_index); } /** * Return java return type signature of method. */ public String getReturnType(){ String rttype = (new TypeSignature(getInternalSig())).getReturnType(); return rttype; } /** * Return java type parameter signature. */ public String getParameters(){ String ptype = (new TypeSignature(getInternalSig())).getParameters(); return ptype; } /** * Return code attribute data of a method. */ public byte[] getCode(){ return code; } /** * Return LineNumberTable size. */ public int getnumlines(){ return lin_num_tb.size(); } /** * Return LineNumberTable */ public Vector getlin_num_tb(){ return lin_num_tb; } /** * Return LocalVariableTable size. */ public int getloc_var_tbsize(){ return loc_var_tb.size(); } /** * Return LocalVariableTable. */ public Vector getloc_var_tb(){ return loc_var_tb; } /** * Return StackMap. */ public StackMapData[] getStackMap() { return stackMap; } /** * Return StackMapTable. */ public StackMapTableData[] getStackMapTable() { return stackMapTable; } /** * Return number of arguments of that method. */ public int getArgumentlength(){ return new TypeSignature(getInternalSig()).getArgumentlength(); } /** * Return true if method is static */ public boolean isStatic(){ if ((access & ACC_STATIC) !=0) return true; return false; } /** * Return max depth of operand stack. */ public int getMaxStack(){ return max_stack; } /** * Return number of local variables. */ public int getMaxLocals(){ return max_locals; } /** * Return exception index table in Exception attribute. */ public int []get_exc_index_table(){ return exc_index_table; } /** * Return exception table in code attributre. */ public Vector getexception_table(){ return exception_table; } /** * Return method attributes. */ public Vector getAttributes(){ return attrs; } /** * Return code attributes. */ public Vector getCodeAttributes(){ return code_attrs; } /** * Return true if method id synthetic. */ public boolean isSynthetic(){ return isSynthetic; } /** * Return true if method is deprecated. */ public boolean isDeprecated(){ return isDeprecated; }}我们将下面这个class文件解析之后的数据如下：过程很简单，有兴趣的大家调试一遍就知道了。
import java.io.PrintStream;public class AsmAopExample$Foo{ public static void execute() { AsmAopExample.Monitor.start(); System.out.println("test changed method name"); try { Thread.sleep(10L); } catch (InterruptedException e) { e.printStackTrace(); } AsmAopExample.Monitor.end(); }}
- open jdk javap对于class文件的解析分析
- class文件字节码分析工具：javap
- Javap反编译class文件
- javap命令将java的class文件反汇编
- javap——查看class文件的方法
- javap - Java class文件分解器
- javap自己解析的源码
- jdk源码分析--了解class文件
- JDK中javap工具的使用
- 用javap命令查看Java的static块在.class文件中的表示
- 如何利用Javap工具对.class文件进行查看
- 解析java的*.class文件
- 查看Class文件的JDK版本
- 查看class文件的编译jdk版本
- 如何确认class文件的jdk版本
- 查看class文件的jdk版本
- Java class文件的JDK编译版本号
- 如何查看class文件的jdk版本
- c++11的std::memory_order
- 关于ＭＡＶＥＮ的初学
- 变量与常量
- chkconfig: command not found
- smartclient框架组件介绍4(ResourceTreeGrid,HTMLPane)
- open jdk javap对于class文件的解析分析
- Android 布局笔记
- Scaleform Gfx的Demo
- 敏捷开发“松结对编程”系列之十：L型代码结构（技术篇之一）
- autobench快速入门
- WPF 密码框输入密码时强制使用英文输入法
- 八款开源 Android 游戏引擎 (巨好的资源)
- Linux在线文档man、info的使用
- js正则表达式
