Java使用winrar解压缩

JAVA JDK中的解压缩似乎不能解压缩我们手工压缩的RAR文件，只能解压JDK中的API压缩的RAR
所以想出以下用WINRAR命令行方式的解压缩
package edu.nwpu.vcampus.util;
import java.io.File;  
 
public class ZipUtil {  
 
    public static final String winrarPath = "C:\\Program Files\\WinRAR\\WinRAR.exe";  
    public static boolean unzip(String zipFile) {  
        boolean bool = false;  
        File f=new File(zipFile);
        if(!f.exists())
        {
         return false;
        }
        String folder = f.getParent();
        System.out.println(folder);
        String cmd = winrarPath + " X " + zipFile + " "+folder; 
        //cmd="C:\\Program Files\\WinRAR\\WinRAR.exe X  D:\\a.rar D:\\a";
        System.out.println(cmd);    
            try {  
                Process proc = Runtime.getRuntime().exec(cmd);  
                if (proc.waitFor() != 0) {  
                    if (proc.exitValue() == 0) {  
                        bool = false;