http断点续传简单实现（java)

/* WRU@i;l  
**SiteFileFetch.java 8b#Yd  
*/ <LA`PbQa  
package NetFox; "Jv,QTIcS  
import java.io.*; |jCE9Ve#  
import java.net.*; 2w.9Q (Sn  
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7 +W?Qo  
public class SiteFileFetch extends Thread { 9@&Z`b_  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {Z{NH:^  
long[] nStartPos; //开始位置 qh'f,#dI}  
long[] nEndPos; //结束位置 H ]N/Y{  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rF j)5~  
long nFileLength; //文件长度 '<E8<b
i  
boolean bFirst = true; //是否第一次取文件 Xrzh*sp  
boolean bStop = false; //停止标志 <)*g7  
File tmpFile; //文件下载的临时信息 x /Ky: Ky  
DataOutputStream output; //输出到文件的输出流 G cLp"  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9j>sRE1  
public SiteFileFetch(SiteInfoBean bean) throws IOException <t|9`l_XW  
{ 4uE5h~0Z  
siteInfoBean = bean; Q; /!oA_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); $vicHuX!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); z E7ocul  
if(tmpFile.exists ()) +cOI`4`$  
{ eVK<%r=  
bFirst = false; 'C?f"P:X{  
read_nPos(); 01d26`G$i~  
} `?|]:7'<  
else mUY:S |  
{ ,Vn]Ft?n  
nStartPos = new long[bean.getNSplitter()]; .j4ziRa-  
nEndPos = new long[bean.getNSplitter()]; ]j#$.$q  
} 71m-W#zyA  
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} h.+&=s!Nsy  
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public void run() E@}j}/%'O  
{ _!g NF=  
//获得文件长度 <TROs!x$a  
//分割文件 u~T$F/]k>  
//实例FileSplitterFetch H;!hp0y  
//启动FileSplitterFetch线程 f*&JfP  
//等待子线程返回 Fea\ eB  
try{ Jn[ K0GV  
if(bFirst) c\
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{ 5pyvs;As  
nFileLength = getFileSize(); <cOE6;d#  
if(nFileLength == -1) uV:uXQni``  
{ Pds*M?&F  
System.err.println("File Length is not known!"); 4qXUk:C@m  
} 8ch~UBq/  
else if(nFileLength == -2) 9: |K]y  
{ $YQ&\[pDA  
System.err.println("File is not access!"); KX}dn:;(3  
} ZV^J5wYE  
else Fmle|  
{ MifgRUe  
for(int i=0;i<nStartPos.length;i++) HNyDWD)_  
{ 
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); P FFw$\j  
} )Ua2x@j'C@  
for(int i=0;i<nEndPos.length-1;i++) q9(}wvtr  
{ m@2xC,@  
nEndPos = nStartPos[i+1]; Bw7:ry  
} %((3'le  
nEndPos[nEndPos.length-1] = nFileLength; K}(n;6\  
} F"P:9`/  
} '\YhRU  
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//启动子线程 f?^xh  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Xz@;`>8i  
for(int i=0;i<nStartPos.length;i++) #]HjP\C  
{ fw};.M  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Donf9]&U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ph_m'fbf  
nStartPos,nEndPos,i); /;$ew~}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )Bvu[rUy  
fileSplitterFetch.start(); g]Ny?61  
} 3VBV_/i;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H#`?toS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); O5*uL{pvT{  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =YsT
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nEndPos = " + nFileLength); HON[{Oq  
// fileSplitterFetch[nPos.length-1].start(); iDxgAV f*  
.7rsbZzs  
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//等待子线程结束 o=2`N2AL  
//int count = 0; li XD2N  
//是否结束while循环 *,*5sV  
boolean breakWhile = false; sjkl? _  
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while(!bStop) !K)|e4$  
{ /VZU3p<~  
write_nPos(); g<c^\WG  
Utility.sleep(500); 2g==98>cg  
breakWhile = true; bxHk0w  
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for(int i=0;i<nStartPos.length;i++) 78#ud15Ml  
{ ;9sVWJJCw  
if(!fileSplitterFetch.bDownOver) qz2d'OhmtH  
{ 7U0):11X#  
breakWhile = false; 
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break; <v^.FxId  
} -e\kIK %  
} ~WLsqP5Y~a  
if(breakWhile) U]3JCZ{]0E  
break; Bv*h?`Q  
 \hc9Rk  
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//count++; ^i7a2< z  
//if(count>4) `Yve  
// siteStop(); 4D
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} Y" |U$  
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System.err.println("文件下载结束！"); ~epkRO="  
} gI{F"7fa=  
catch(Exception e){e.printStackTrace ();} C`K/ai{4  
} QKQy)g  
^jA^~h3(W  
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//获得文件长度 z [{%.kA  
public long getFileSize() ~!u94_:  
{ ^PszZ10T  
int nFileLength = -1; -fn~y1  
try{ ]7@Dqd-/S  
URL url = new URL(siteInfoBean.getSSiteURL()); }c:
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8t; nU;E*  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9r}}
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int responseCode=httpConnection.getResponseCode(); <C(2(3  
if(responseCode>=400) ,)8Hl[y  
{
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processErrorCode(responseCode); =!aV?kNS8  
return -2; //-2 represent access is error 8a1{x(\z.  
} 4Qs#ws])  
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String sHeader; 0't)fnI#  
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for(int i=1;;i++) Jr zU-g  
{ rv>6k:(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :PJjy6,1  
//Utility.log(in.readLine()); Fx2&ji6u  
sHeader=httpConnection.getHeaderFieldKey(i); NU"X*g-x^  
if(sHeader!=null) ZgtOy|?|  
{ wu3ZSLY  
if(sHeader.equals("Content-Length")) oizoKwp%  
{ Dc5XU3Eu`  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); aQuENsB  
break; gUlZcb  
} eS M!_2  
} n$9!G  
else JM0)x}]+  
break; _Yv9u'q"  
} f.WtD`Oas  
} p+Xz9A"  
catch(IOException e){e.printStackTrace ();} pK%'S  
catch(Exception e){e.printStackTrace ();} R8_qZ;t:z  
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Utility.log(nFileLength); -lHJ\=  
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return nFileLength; 5NK:94&JE  
} z Ey&%Ok  
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//保存下载信息（文件指针位置） 1k`!w}  
private void write_nPos() ?*HlAVDcFT  
{ 7Uh}|6PU  
try{ i "xq SLf=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0td;Ag  
output.writeInt(nStartPos.length); Q{l;8MCL  
for(int i=0;i<nStartPos.length;i++) _eS*e-@O5  
{ hsh W5j  
// output.writeLong(nPos); *niQ*A  
output.writeLong(fileSplitterFetch.nStartPos); 5 ,HNb
 
output.writeLong(fileSplitterFetch.nEndPos); 1RLSeT  
} 1JY4E2Q  
output.close(); lB3X1e9  
} D UeT  
catch(IOException e){e.printStackTrace ();} &yuerNK  
catch(Exception e){e.printStackTrace ();} ZsE8eD  
} 7u;B[qH  
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//读取保存的下载信息（文件指针位置） d)@MMF  
private void read_nPos() i*3_ivc)  
{ Ek:u[Uw\  
try{ /V^S)5r  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6%>0g^`)9Y  
int nCount = input.readInt(); q\\J9`Q$J  
nStartPos = new long[nCount]; gDH x+"?  
nEndPos = new long[nCount]; K4KmoGb  
for(int i=0;i<nStartPos.length;i++) 9%8T09I!  
{ W cnYD)  
nStartPos = input.readLong(); CwAl-o  
nEndPos = input.readLong(); }v?{npEOt+  
} h6#  
input.close(); iJcl0)|  
} rW6LMkt72  
catch(IOException e){e.printStackTrace ();} Y\lBPp0{\v  
catch(Exception e){e.printStackTrace ();} =1D*K%  
} }-!$KR]:s  
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private void processErrorCode(int nErrorCode)  /YHeO
 
{ $O[ut.  
System.err.println("Error Code : " + nErrorCode); (%bfNs|  
} w ^A0l.{  
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//停止文件下载 @{j-B IRZ0  
public void siteStop() ?r/7:  
{ aw~OvnX E  
bStop = true; Z@>>ZS1Do  
for(int i=0;i<nStartPos.length;i++) fK[9<"PC0  
fileSplitterFetch.splitterStop(); kG{(Qi  
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} TYp{nWwi  
} g wk\[I`;  
//负责部分文件的抓取 *J6qL! ["  
**FileSplitterFetch.java V[%r5!83H  
*/ 0pu'K)Rb  
package NetFox; !R-UL#w9W'  
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import java.io.*; oY{*X6:6<  
import java.net.*; @9^kl$  
:x_l"y"  
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public class FileSplitterFetch extends Thread { &#WTXTr0=  
y jb.6  
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String sURL; //File URL ~j UK-E  
long nStartPos; //File Snippet Start Position ?p`}6s Q}  
long nEndPos; //File Snippet End Position E3`KO'v%  
int nThreadID; //Thread's ID ~_K  
boolean bDownOver = false; //Downing is over Dq\#:NnKvx  
boolean bStop = false; //Stop identical WvR}c  
FileAccessI fileAccessI = null; //File Access interface "~GudK &  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :QN,T3i'/3  
{ \4V'NTjB  
this.sURL = sURL; GU!|J71z  
this.nStartPos = nStart; am`eist:  
this.nEndPos = nEnd; J9/w_,,R$  
nThreadID = id; "5{\0CfS  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4((Z8@iX/  
} 9~N7hLT  
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public void run() u+{5c5_  
{ r,F'Jd5  
while(nStartPos < nEndPos && !bStop) DK:d'zb  
{ p/@z4TCNX  
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try{ `OduBUI]]  
URL url = new URL(sURL); |GIT{_JE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #*w$JH  
httpConnection.setRequestProperty("User-Agent","NetFox"); X]`\NNx  
String sProperty = "bytes="+nStartPos+"-"; S!rUdxO  
httpConnection.setRequestProperty("RANGE",sProperty); 7/Ew(X8Fs  
Utility.log(sProperty); CvlAn7r,@  
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InputStream input = httpConnection.getInputStream(); C
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//logResponseHead(httpConnection); Rd2*  
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byte[] b = new byte[1024]; N#|c2n+  
int nRead; /bg8oB4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2H4+D)  
{ d`^j\b>5(  
nStartPos += fileAccessI.write(b,0,nRead);
}P^{\SDX  
//if(nThreadID == 1) LM0TSB?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ucTkWqG  
} -6#i~a]  
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Utility.log("Thread " + nThreadID + " is over!"); 1298&C@  
bDownOver = true; 5C/u`{4]Hg  
//nPos = fileAccessI.write (b,0,nRead); F*}b),  
} 3<B{-z  
catch(Exception e){e.printStackTrace ();} <;M6s~  
} &u$l2hSS  
} |IZG`
3  
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//打印回应的头信息 xOP\ +(  
public void logResponseHead(HttpURLConnection con) tw^V?4[Miu  
{ r/8,4:rh  
for(int i=1;;i++) t'~:me!  
{ Z3 &8(vw  
String header=con.getHeaderFieldKey(i); YAsvw\iseK  
if(header!=null) )\p@E3Uxf  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J0^p\mG  
Utility.log(header+" : "+con.getHeaderField(header)); AlGD .K  
else ,v(G2`Z  
break; owQLAV  
} #~nI^ ggW  
} vrh}X[JEw'  
<PXA`]x~  
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public void splitterStop() |qfnbi-\  
{ D`iWf3a.  
bStop = true; L[<MBgFKv  
} SrU,-mA W  
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@ -g^R4e<  
} *j8w" 4  
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/* nbhx2@Teqe  
**FileAccess.java n0nkv[  
*//文件访问(定位，写) 9NKZE?5P|D  
package NetFox; HH8a"Hq)  
import java.io.*; /TS>I8V!  
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public class FileAccessI implements Serializable{ <Eq^rh  
l0Y(9(M@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s|YY i~  
RandomAccessFile oSavedFile; ^h=;]vxO  
long nPos; >L)Xyq  
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public FileAccessI() throws IOException C'kd>LAGu  
{ l{vi{9n)  
this("",0); w~Es,@  
} "0nto+v  
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public FileAccessI(String sName,long nPos) throws IOException qDOx5.d  
{ oQFpIX;\m  
oSavedFile = new RandomAccessFile(sName,"rw"); >e"1a/2%>&  
this.nPos = nPos; Va?wG3w  
oSavedFile.seek(nPos); znX2W0V  
} ;w[|IRa  
:@19,.L  
'0z@Jevd?  
public synchronized int write(byte[] b,int nStart,int nLen) 8M8=
uw~#  
{ P7<~S8)Y  
int n = -1; zLC\Rc4  
try{ )=ZWn,ZB  
oSavedFile.write(b,nStart,nLen); wIL5-k,  
n = nLen; ^BSMlKyB  
} wQ@@|Cj4L  
catch(IOException e) WRL &tz  
{ #W'jNX,h  
e.printStackTrace (); W/xb[w9v  
} l\jf]BHX'  
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return n; /k(0}g=\  
} :1=
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} D@FJVF7c  
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/* 315Rk!{AJ  
**SiteInfoBean.java \} P}H  
*/ ``K.4sG  
package NetFox; -E?h^J&U  
!~"q$T>@  
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public class SiteInfoBean { I4gyGg$H  
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r68'DJ&m3  
private String sSiteURL; //Site's URL 0=yKE J  
private String sFilePath; //Saved File's Path 3QZw  
private String sFileName; //Saved File's Name $yI!YX&  
private int nSplitter; //Count of Splited Downloading File ?:~Y%4;  
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public SiteInfoBean() XM>ByfD{  
{//nSplitter的缺省值为5 \<]nv}1O  
//default value of nSplitter is 5 hA/K>Z  
this("","","",5); LH3PgGi,  
} _Z@- q  
0ppZ~}&  
#p6#,PZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1j9.Q;9  
{ a&M{y  
sSiteURL= sURL; Oy&Myjny<  
sFilePath = sPath; IH'DCY:  
sFileName = sName; #=q)>+\  
this.nSplitter = nSpiltter; "#qyX[\  
Ks{^R`Oau  
M~zdcVTbH  
} 4JT9EKo
 
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public String getSSiteURL() pEw &i  
{ `$fwLC3j  
return sSiteURL; <pK
72  
} k#w[GL|T  
3;>|*(cO  
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public void setSSiteURL(String value) AJI,>I,}}  
{ Wu,'S;>C  
sSiteURL = value; bH~ue5q  
} ~NMa
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public String getSFilePath() OGzth$7A  
{ MrXhVZ"d*  
return sFilePath; @c9VCG D  
} >s1'I:8  
JD^(L~n]  
'@3hU|jO!  
public void setSFilePath(String value) wh<+.Zp  
{
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sFilePath = value; e3yBB*@  
} w<lHY=z E  
3BDAvdJ4.  
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public String getSFileName() EdhT;!  
{ )ZEUD] X  
return sFileName; tT ~}lW)Y  
} [kDjht|$>  
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public void setSFileName(String value) ,)@Q,EHN;  
{ 3tMs613  
sFileName = value; Vp.($  
} fq~<^B  
k^
}8=,j}  
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public int getNSplitter() .nJErC##  
{ loZJV M  
return nSplitter; y<.0+YL-e+  
} (A}##h  
;3s_#L  
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public void setNSplitter(int nCount) /8VM.fr$  
{ wyzj[PDS  
nSplitter = nCount; Eb7qM.Q] &  
} l4I
@6@  
} ZTfs&5  
;\DXRKR  
+ G#qS1  
/* y]xG@;4M  
**Utility.java :[3{-.c  
*/ 0C#1/o)o  
package NetFox; GU8b_~Gk?  
rZ
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public class Utility { {0+gPTp  
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public Utility() N|EH`eu^i  
{ g7res  
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} n_Px=s!1p@  
RLOB  
//线程睡眠 ({ads_l  
public static void sleep(int nSecond) XO~xbG7>gZ  
{ gQ%'2m+  
try{ I2hX;pk,  
Thread.sleep(nSecond); "Sz pFw  
} ()6)|A<^U  
catch(Exception e) D^W6Cq5\  
{ /-TJtR4>  
e.printStackTrace ();
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} `VCU`Y
  
} DBYD>UA  
x_CB'Rr6  
//日志 (.-3q;)6  
public static void log(String sMsg) % < D  
{ OM*N)*  
System.err.println(sMsg); W2G`
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} al$G OMi  
.9_]8T  
3/+9#  
public static void log(int sMsg) QkBT,c  
{ .|}ogTEf  
System.err.println(sMsg);
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} p&ytUTna  
} 8'Sw?FbVA/  
.%j&#(!  
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/* P/5bNK!  
**TestMethod.java Xm`jD'G  
*/ -K hXb  
package NetFox; h~)oiT2v  
4vq,W_n.hQ  
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public class TestMethod { 2qLRcA=R  
SV}
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public TestMethod() rs2G{a  
{ ///xx/weblogic60b2_win.exe +e+hIMur  
try{ _IBIx\F  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6"U&i9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
h<U<KO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M/C7<?&  
fileFetch.start(); Aq@_^mq1A  
} q[`)A?Ae  
catch(Exception e){e.printStackTrace ();} 7Gd)=Q{uur  
O3WhO@`6)  
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} zc>/1>?M  
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L\_MZ*<0[  
public static void main(String[] args) e0Cr>I5/e  
{ 9AK<<Mge.  
new TestMethod(); iD+Q\l;%  
} b3N>RPsHS  
} ]`)50\pdw  
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