修改Jar自述文件

public class ModifyManifest extends AbstractCmdTest{
// private String jarPath="E:\\xxx\\junit-4.8.1.jar"; //要修改自述文件的Jar包路径
// private String jarPath2="E:\\xxx\\junit.jar"; //jar包零时存放路径

@Override
public boolean execute() {
String jarPath=this.getInputInfo("jarPath").toString(); //获取需要修改自述文件的Jar包路径
String jarPath2=this.getInputInfo("jarPath2").toString();//获取Jar零时存放路径
Map manifestMap=(Map) this.getInputInfo("manifest"); //获取带有描述信息的Map
try {
JarFile jarFile = new JarFile(jarPath); //得到要修改的Jar包
Manifest mf=jarFile.getManifest(); //得到其自述文件
StringBuffer attributes=new StringBuffer(); //存放描述信息的StringBuffer
Set maniSet=manifestMap.keySet();
for(Object obj:maniSet){ //向StringBuffer中添加Map中的信息
String key=obj.toString();
String value=(String)manifestMap.get(obj);
attributes.append(key+value+"\n");
}

//把Map中的信息以UTF-8的形式放到流
InputStream mfStream = new ByteArrayInputStream(attributes.toString().getBytes("UTF-8"));
Manifest newmf=new Manifest(mfStream); //用包含Map信息的流生成Manifest
SoftReference<Manifest> manifest=new SoftReference(newmf); //得到Manifest 软引用 
Field filed=JarFile.class.getDeclaredField("manRef"); //得到SoftReference<Manifest>反射
filed.setAccessible(true);
filed.set(jarFile, manifest);
//*************输出信息确认修改正确*********
Attributes a=jarFile.getManifest().getMainAttributes();
Set i=a.keySet();
for(Object o:i){
System.out.println(o.toString()+a.getValue(o.toString()));
}
//生成修改后的文件
JarOutputStream jarOutput=new JarOutputStream(new FileOutputStream(jarPath2),newmf);//用新的Manifest文件生成Jar输出流
JarInputStream jarInput = new JarInputStream(new FileInputStream(jarPath)); //jar文件输入流 
JarEntry jarEntry=null;
byte[] jarByte=new byte[4096];
while((jarEntry=jarInput.getNextJarEntry())!=null){
jarOutput.putNextEntry(jarEntry);
int length;
while((length=jarInput.read(jarByte))!=-1){
jarOutput.write(jarByte, 0, length);
}
jarOutput.closeEntry();
}
jarOutput.flush();
jarOutput.close();
jarInput.close();
//用新生成的jar包覆盖原来的jar包
FileInputStream fileInput=new FileInputStream(jarPath2); 
FileOutputStream fileOutput=new FileOutputStream(jarPath);
byte[] fileByte=new byte[4096];
int fileLength;
while((fileLength=fileInput.read(fileByte))>0){
fileOutput.write(fileByte, 0,fileLength);
}
fileOutput.flush();
fileOutput.close();
fileInput.close();
File f=new File(jarPath2);
f.delete();
return true; //返回true
} catch (IOException e) {
e.printStackTrace();
} catch (SecurityException e) {
e.printStackTrace();
} catch (NoSuchFieldException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} 
return false;
}
public static void main(String[] args){
//输入参数
Map manifest=new HashMap();
manifest.put("Manifest-Version:", " 123456789.0");
manifest.put("Ant-Version:", " Apache Ant 1.789.1");
manifest.put("Created-By:", " 1.5.0_20-141 (Apple Inc.)");
manifest.put("guga:", " gaaaaa");

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