http断点续传简单实现（java)

/* JgEPzHgx  
**SiteFileFetch.java jZx.MBVy]  
*/ Uf4A9$R.G  
package NetFox; ;=fOyg  
import java.io.*; Y{ijSOl3  
import java.net.*; Yw7txp`i  
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public class SiteFileFetch extends Thread { m&a.i B  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 
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long[] nStartPos; //开始位置 Q8.=w  
long[] nEndPos; //结束位置 Lyo!}T  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Vsw]v  
long nFileLength; //文件长度 `\_>P@qz  
boolean bFirst = true; //是否第一次取文件 +Nn $  
boolean bStop = false; //停止标志 l1HMH?0|  
File tmpFile; //文件下载的临时信息 3Xcjr2]~  
DataOutputStream output; //输出到文件的输出流 H{hd1  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） fqpbsM;M]  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5nF46c  
{ B>C+qj@  
siteInfoBean = bean; /<C}v~r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); M~+}ss  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); CiF(   
if(tmpFile.exists ()) ( f]@lNmx  
{ Jui:Ms
 
bFirst = false; QiKci%=SX  
read_nPos(); J'}G~rB<<  
} ~?#>QN\\c  
else F\0>/  
{ C-)mP- |8  
nStartPos = new long[bean.getNSplitter()]; 5ir Ffr  
nEndPos = new long[bean.getNSplitter()]; L)(JaZyV5  
} 1V ,Mk#_  
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} N> 7sG(!'"  
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public void run() Eqizx~eqq  
{ pKZRgA#kN  
//获得文件长度 }uR[H2D`L  
//分割文件 wE3L,yx=  
//实例FileSplitterFetch A4uKE"WE  
//启动FileSplitterFetch线程 S@Iza9\|@  
//等待子线程返回 #)r^ZA&E  
try{ 4t 5i9+h  
if(bFirst) |VX )S!  
{ &u+l`F^Z  
nFileLength = getFileSize(); VdL*"i  
if(nFileLength == -1) ~ECIL7,  
{ pl}nbY  
System.err.println("File Length is not known!"); C]EkVcKFA  
} *c<6 Er>s  
else if(nFileLength == -2) OI^??joQ  
{ o%yfR.M6$  
System.err.println("File is not access!"); !),eEy  
} v*";A  
else t]IHQ8  
{ y`,;m#frT  
for(int i=0;i<nStartPos.length;i++) jFDVd;#CS  
{ D~ogq]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9| g]M:{  
} 'GI| t  
for(int i=0;i<nEndPos.length-1;i++) m>{a<N  
{ -=cxUDB  
nEndPos = nStartPos[i+1]; TUBpRABH  
} ~] &yHzp2  
nEndPos[nEndPos.length-1] = nFileLength; TTa$w
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} 8TBv~Qu  
} FMOO  
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@ D,]v:  
//启动子线程 f@@7?5fW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; l"zA~W/  
for(int i=0;i<nStartPos.length;i++) ;~-ZN?8   
{ TMsc5E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %lk^(@+ T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), DFkDlx  
nStartPos,nEndPos,i); bN\;m^xfu  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kzk8b?rOA  
fileSplitterFetch.start(); z+Guu8  
} v,'k2H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;kI)j ?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4Ei8G]O $_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", t[r6jo7  
nEndPos = " + nFileLength); Sa[?B  
// fileSplitterFetch[nPos.length-1].start(); =X1oB,W{  
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//等待子线程结束 )1f%kp#]  
//int count = 0; ]]o?!NX
 
//是否结束while循环 G|oO  
boolean breakWhile = false; G} f9:G  
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while(!bStop) ~GE|,Np  
{ Ay7PU  
write_nPos(); |<Y~\|  
Utility.sleep(500); /X]gm\x7s  
breakWhile = true; s~QIs  
/Y=_EOS  
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for(int i=0;i<nStartPos.length;i++) QQ`tSYgex  
{ m@Dra2Cv'@  
if(!fileSplitterFetch.bDownOver) M"Af_Pbx  
{ u6 QW*8b4  
breakWhile = false; 4.Q[Tu  
break; >V?W_oM)  
} ^F'~|zc"C  
} H:EK&$sU  
if(breakWhile) IgjPy5k  
break; &pf"35ll  
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L@'2}7N1%  
//count++; MDQ:6Ri  
//if(count>4) &pQ[(|=(  
// siteStop(); h3bQ<?m  
} 7H*,HZc@=  
Q;N)$Xx  

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System.err.println("文件下载结束！"); h<V,0sZ&:  
} o|u4C{j  
catch(Exception e){e.printStackTrace ();} 'qUM38s  
} ^*YoNd_kpN  
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//获得文件长度 q:nUn?zB  
public long getFileSize() 3ZC@q #R A  
{ ,Ne9x\F  
int nFileLength = -1; ALn_ifNh  
try{ 3dz{"hV  
URL url = new URL(siteInfoBean.getSSiteURL()); S|xwYaoy%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n*ROlCxV  
httpConnection.setRequestProperty("User-Agent","NetFox"); k( I
k+=u  
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int responseCode=httpConnection.getResponseCode(); eIy:5/s  
if(responseCode>=400) fs yVu|G  
{ w_V A:]j4  
processErrorCode(responseCode); s$zm)y5  
return -2; //-2 represent access is error [ #ih o(/  
} fN@ZJ~F%j  
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String sHeader; & kVa*O  
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for(int i=1;;i++) T{2)d]Y  
{ b)x0;8<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); iITMBS`}  
//Utility.log(in.readLine()); ps?su`  
sHeader=httpConnection.getHeaderFieldKey(i); ~%lA!tsek  
if(sHeader!=null) m,"-/)  
{ ?hAO-*);  
if(sHeader.equals("Content-Length")) YcV^Fqi!  
{ w >%^pO~}`  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); BQ<\[H;  
break; VxS3lR=  
} l]~9BPsR  
} n!AW9]  
else q6*i/"mN*  
break; $UdBZT-  
} Tt9cX}&&  
} wd32q7lGo1  
catch(IOException e){e.printStackTrace ();} j^;P=L0=  
catch(Exception e){e.printStackTrace ();} GqNOWK2O  
"+4Jmf9  

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Utility.log(nFileLength); vNs`UkA  
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return nFileLength; }Xk_ xQVt{  
} (,t[`z  
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//保存下载信息（文件指针位置） E%;$vj'2  
private void write_nPos() cl1ygpf(  
{ n_rpT.[  
try{ 1_Ks*7vuq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /F9Dg<#a  
output.writeInt(nStartPos.length); j!NXNuy:  
for(int i=0;i<nStartPos.length;i++)  @;KYvDY  
{ <wb6)U.  
// output.writeLong(nPos); -"S94<Y  
output.writeLong(fileSplitterFetch.nStartPos); SUIJ{!F/  
output.writeLong(fileSplitterFetch.nEndPos); `R xCs`  
} &;pM<h  
output.close(); Q"U%]2@=  
} *U
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catch(IOException e){e.printStackTrace ();} ;du},>T$n  
catch(Exception e){e.printStackTrace ();} {$Uj&/IC  
} F-b]>3r  
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//读取保存的下载信息（文件指针位置） ^fe,A=k~1  
private void read_nPos() f8SO:ihXL  
{ IY8<^Q']  
try{ i].E1},%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); SPRTJdaC9  
int nCount = input.readInt(); LC##em=Y  
nStartPos = new long[nCount]; p-_9I7?  
nEndPos = new long[nCount]; E3Y0@r  
for(int i=0;i<nStartPos.length;i++) 8m=R" %h  
{ Cse`MP  
nStartPos = input.readLong(); ?>{u@tYL  
nEndPos = input.readLong(); T@{ab1KV  
} R) :Xs.  
input.close(); *k;bkd4x  
} +6l#hO7h  
catch(IOException e){e.printStackTrace ();} [<{r~YFjWW  
catch(Exception e){e.printStackTrace ();} #]5KWXC'~  
} kr~n5WiAZ  
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private void processErrorCode(int nErrorCode) Nu?A>Q  
{ Ipq0 1 +  
System.err.println("Error Code : " + nErrorCode); nyqX\m-  
} AZ4?N.X?  
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//停止文件下载 "_LqIW1  
public void siteStop() WkE="E}  
{ ~GX ]K H  
bStop = true; YkMFU'?[  
for(int i=0;i<nStartPos.length;i++) B+~ /-3  
fileSplitterFetch.splitterStop(); Rc{R^5B  
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} w' J`$=  
} !ry+{v+A  
//负责部分文件的抓取 p&V64L:V  
**FileSplitterFetch.java 4G' E<ab  
*/ [jlum>K  
package NetFox; %X.g+uu  
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import java.io.*; ,D*bLXWh  
import java.net.*; <yX u!  
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public class FileSplitterFetch extends Thread { [pp|*@1T  
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String sURL; //File URL  XD8I.q  
long nStartPos; //File Snippet Start Position 0iZeU:FE  
long nEndPos; //File Snippet End Position hp/pm6  
int nThreadID; //Thread's ID BF2U$-k4  
boolean bDownOver = false; //Downing is over &PL=nI\)  
boolean bStop = false; //Stop identical 7]1a3Jk  
FileAccessI fileAccessI = null; //File Access interface !*~QB4\2b  
hx;kNcPbI  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gl`J(  
{ o$;&q *  
this.sURL = sURL; 3{~(_  
this.nStartPos = nStart; Spx%`O<  
this.nEndPos = nEnd; r9N?z2X  
nThreadID = id; Cj4Y, N  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 k Qr  
} c CDT27@  
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public void run() W).Kq-  
{ oz.z>+Q  
while(nStartPos < nEndPos && !bStop) bcy  
{ v'?o#_La+  
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try{ k*6"!J%A  
URL url = new URL(sURL); v@GhwL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b:~#;$g  
httpConnection.setRequestProperty("User-Agent","NetFox"); .'H$|"(v  
String sProperty = "bytes="+nStartPos+"-"; }PBL  
httpConnection.setRequestProperty("RANGE",sProperty); $'5rS$]a/  
Utility.log(sProperty); ;a@riPqx!  
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InputStream input = httpConnection.getInputStream(); 8'zl\:@N  
//logResponseHead(httpConnection); O/Hj-u6&A  
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byte[] b = new byte[1024]; .-T P1C  
int nRead;
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) GXD<X_[  
{ sUc[!S:/  
nStartPos += fileAccessI.write(b,0,nRead); fa/o4S<  
//if(nThreadID == 1) ^{=UKf{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B[
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} . 70=xH  
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Utility.log("Thread " + nThreadID + " is over!"); *My9r.F5o  
bDownOver = true; d oEuKT  
//nPos = fileAccessI.write (b,0,nRead); yFmy  
} 4OJD_  
catch(Exception e){e.printStackTrace ();} J!~kqNI  
} `^^t#sT  
} 2(~Zl\  
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//打印回应的头信息 '-N5F  
public void logResponseHead(HttpURLConnection con) H?Sv6W.~  
{ <>f;g"qS  
for(int i=1;;i++) O>nMeU  
{ {j`8XWLZZN  
String header=con.getHeaderFieldKey(i); L;M@]  
if(header!=null) s1::\&`za  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )i:*r8*~  
Utility.log(header+" : "+con.getHeaderField(header)); (X\]!'A  
else dwUDhQt3Q  
break; `w>D6K+  
} H}G 9gi  
} :8/ 6dx@Y(  
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public void splitterStop() =Gzs+6A8  
{ }{@y]DcdM4  
bStop = true; ZD|F"v.  
} $n!5JS@40  
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} 1##@'L|u  
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/* J[Mj8ee#  
**FileAccess.java Ev3'EA~`  
*//文件访问(定位，写) C:^ :^y  
package NetFox; $]};EI#  
import java.io.*; SKNHLE}  
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public class FileAccessI implements Serializable{ +p jB/#4  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 VrfEa d  
RandomAccessFile oSavedFile; ?
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long nPos; (X5y%~;V5a  
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public FileAccessI() throws IOException >vXJ9\  
{ [) >Yp-n  
this("",0); L.-qTh^P  
} AsuugcN*  
z(.,BB[  
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public FileAccessI(String sName,long nPos) throws IOException s.;'-oA  
{ kxEq_FX  
oSavedFile = new RandomAccessFile(sName,"rw"); wX6-WQR  
this.nPos = nPos; ju;OQC~[L]  
oSavedFile.seek(nPos); iumwhb  
} ?-3G5yy  
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public synchronized int write(byte[] b,int nStart,int nLen) tQT<1Q02i  
{ baTd;`Pn  
int n = -1; lg )xQV  
try{ WEG!;XZ  
oSavedFile.write(b,nStart,nLen); UfO='&U^  
n = nLen; &#u\@Qze  
} ALO/{:l(  
catch(IOException e) _D{FQRU<YD  
{ t(PA+~sIp  
e.printStackTrace (); }#E]efjs  
} A-L)2.M  
| ~>7_:  
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return n; !@P{s'<:  
} >b0Bvx-  
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} 2{l|<'  
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/* D8E^[w!  
**SiteInfoBean.java I(&N2L$-  
*/ *&#M`
,#  
package NetFox; Si23w'T  
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public class SiteInfoBean { C-,#t5eir  
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private String sSiteURL; //Site's URL #7:ah  
private String sFilePath; //Saved File's Path "9hD4R  
private String sFileName; //Saved File's Name `e7vSp  
private int nSplitter; //Count of Splited Downloading File fn7?g  
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public SiteInfoBean() V^n=@CZT9C  
{//nSplitter的缺省值为5 %)dp a  
//default value of nSplitter is 5 x+'Ea.^  
this("","","",5); kDQE*o  
} l$HBYA\Qh  
/']`}*d  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9X#]Lg?b  
{ ih75C"  
sSiteURL= sURL; L9,GUtK{  
sFilePath = sPath; V}2[chbl
 
sFileName = sName; Lq6nmjL  
this.nSplitter = nSpiltter; ~SA>$  
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} 0/z$W.!  
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public String getSSiteURL() e_rEu'[av  
{ /yUKUXi  
return sSiteURL; /9D mK%d  
} (&V*~OR  
tv`c"Pb  
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public void setSSiteURL(String value) ,*x/L?.Z!  
{ LKZ<\% X  
sSiteURL = value; %|R]nB  
} 6y?uH;SL  
r@'
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public String getSFilePath() w9gfva$&  
{ (otD4VR_  
return sFilePath; mQU t 'j4  
} .]<iRf[\[  
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public void setSFilePath(String value) JH2-'  
{ ]D2d=\  
sFilePath = value; fv* $=m  
} p>T  
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public String getSFileName() @K#}nKN'  
{ 6*|EB|%n  
return sFileName; ose)\rM'  
} 7fT_]H8  
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public void setSFileName(String value) j/ARTaO1]"  
{ ~@}n}aV'!  
sFileName = value; @qA11C.hq  
} pVjOp~=U  
pd.pY*B<[  
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public int getNSplitter() t""Y -M  
{ Nh4&3"g|  
return nSplitter; CzDg?wb  
} &RHx8zScP  
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public void setNSplitter(int nCount) bQ0+Y?,+/  
{ ,n>K$  
nSplitter = nCount; ;__k*<+{.  
} dg(sRTi{  
} ^p%3@)&  
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/* |NFDrm  
**Utility.java W<~u0AyO 3  
*/ IFF1wfC   
package NetFox; A5ckosYyNA  
/}d)g4\j  
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public class Utility { =%[vHQ\%  
`
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{~Q
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public Utility()  N=!k2+  
{ T{'oR .g,  
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} |Ur$H!oe?'  
]<_v;Q<t  
//线程睡眠 s|:
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public static void sleep(int nSecond)  bWZzb&  
{ eQ=6< ^KZ  
try{ 9A\\2Zz6F  
Thread.sleep(nSecond); AC?a:{./  
} +KP&D.wIo  
catch(Exception e) 2>^jMln  
{ ).MV1@s  
e.printStackTrace (); oPF n`8dQ  
}  (S&D  
} `cRRdD:dA  
ORIXcj]  
//日志 ;s$ P?('  
public static void log(String sMsg) ECuNkmUI  
{ *E/CNMn=E  
System.err.println(sMsg); EPEn"{;U  
} I$fm"N  
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public static void log(int sMsg) '@5"p.  
{ {'+.?g  
System.err.println(sMsg); ipRH.1=  
} reNUIDt/c  
} XpT~]q}  
@@6c{r^P  
9*[!ux7h  
/* z) "(&__  
**TestMethod.java ~=$d>ZNQ  
*/ c 1{nOx  
package NetFox; #b;TjnC5{$  
19\ V@d^  
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public class TestMethod { t8~isuiK  
2t#[$2mg\0  
6lQP+! EF  
public TestMethod() RJD(c#r$  
{ ///xx/weblogic60b2_win.exe ooN?x31  
try{ >#5jO9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); mk3,ke8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); LH
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SiteFileFetch fileFetch = new SiteFileFetch(bean); @u-CR8^  
fileFetch.start(); gt(!I^LHYc  
} Gmmh&Uj  
catch(Exception e){e.printStackTrace ();} [5MV$)"!j  
[85tZr]  
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} }Q;^C  
_6\"U5*Y  
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public static void main(String[] args) 3?wL)6Uj8J  
{ VO,F[E~_  
new TestMethod(); R9~c: A4G  
} 'RIx}vPf  
} fRcy$  
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