http断点续传简单实现（java)

/* D{'#er  
**SiteFileFetch.java \%,&~4 !  
*/ 5eX59:vtl  
package NetFox; v.W{x?5  
import java.io.*; &14W
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import java.net.*; v&3O&y/1v  
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public class SiteFileFetch extends Thread { S:Tm23pe  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #Nte^
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long[] nStartPos; //开始位置 ?kt=z4h9(  
long[] nEndPos; //结束位置 U '[?9/T  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1h"_[`L'  
long nFileLength; //文件长度 ,2WH/"  
boolean bFirst = true; //是否第一次取文件 m%QqmTH  
boolean bStop = false; //停止标志 |ia@,*KD  
File tmpFile; //文件下载的临时信息 r9ke,7?  
DataOutputStream output; //输出到文件的输出流 iilyw_$H  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） wVi%
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public SiteFileFetch(SiteInfoBean bean) throws IOException .#^0pv!  
{  }sMW3'V  
siteInfoBean = bean; Fc0jQ@4=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7tH]*T9e>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ccO aCr  
if(tmpFile.exists ()) |*Ot/TvG  
{ q|q::q*  
bFirst = false; "@/ba!L+  
read_nPos(); wsg//Ec]  
} wL<j:>Ke[3  
else ) YSh D  
{ ;]&-MFv#  
nStartPos = new long[bean.getNSplitter()]; j%M @#  
nEndPos = new long[bean.getNSplitter()]; B-Y+F  
} - s|t^  
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} rrQ0qg  
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public void run() `?SGXXC  
{ 6H;kJHn  
//获得文件长度 $T*KaX\{B  
//分割文件 E:Y:X~vy  
//实例FileSplitterFetch y<r44a_!  
//启动FileSplitterFetch线程 onzA7Gre  
//等待子线程返回 < EXWWrm  
try{ ",ad7Y7i  
if(bFirst) silp<13HN  
{ 5c~'!:7  
nFileLength = getFileSize(); '?R=
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if(nFileLength == -1) nx :)k-p_[  
{ I2*oTUSik  
System.err.println("File Length is not known!"); ^"`Z1)V  
} (^S5Sc=  
else if(nFileLength == -2) -q(:%;  
{ L;C|ow^c  
System.err.println("File is not access!"); _z:Qhe  
} zZYH
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else -ddOh<U>  
{ s1@@o#r  
for(int i=0;i<nStartPos.length;i++) 3ExVZu$  
{ Ao!=um5D J  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^4hc+sh0D  
} ork|yj/A  
for(int i=0;i<nEndPos.length-1;i++) 1OPfRDn.bk  
{ [Ye5Y?  
nEndPos = nStartPos[i+1]; ~D!ESe*=  
} 8XkIk7  
nEndPos[nEndPos.length-1] = nFileLength; F25<+1kr  
} sVD([`Nmc  
} i-V0Lm/  
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//启动子线程 *C/KM;&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /T#
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for(int i=0;i<nStartPos.length;i++) gDc]^K4>  
{ 3It8&x:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %f#\i#G<k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Jh(mbD  
nStartPos,nEndPos,i); mE_iS?1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); agTK=  
fileSplitterFetch.start(); %((cFQ9  
} T=yCN#cqQ`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #?5VsD8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @YrGyq  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", '7=<#Blc  
nEndPos = " + nFileLength); U:Fpj~E_w  
// fileSplitterFetch[nPos.length-1].start(); c8tP+O9  
j5A\y^Kv  
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//等待子线程结束 SJF2k[da  
//int count = 0; ~:s!].H  
//是否结束while循环
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boolean breakWhile = false; v5gQ9  
*U2Ck<"]  
8\u;Wf  
while(!bStop) W-!dMa  
{ 6z`8cI+LRw  
write_nPos(); ]d~MEa9Y|  
Utility.sleep(500); 7Fc |  
breakWhile = true; wtUG^hV #_  
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for(int i=0;i<nStartPos.length;i++) TR_(_Yd?36  
{ R3cG<MjmK  
if(!fileSplitterFetch.bDownOver) $$/S8LmmK  
{ @>Biyb  
breakWhile = false; @]yQJuXA&Z  
break; 6vZt43"m?\  
} IBF.&[[S  
} Q)9369<A  
if(breakWhile) [y$j9  
break; =1_jaDp  
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2@4MC`&  
//count++; bv_AJ4gS  
//if(count>4) 1w6.  
// siteStop(); mURX I'JkX  
} OHQ3+WJ  
'fXer!L}  
F}\[eFf[  
System.err.println("文件下载结束！"); d!FONi  
} jeyaT^F(   
catch(Exception e){e.printStackTrace ();} ) +*@AME  
} wN$uX#W|  
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//获得文件长度 g9! dpP  
public long getFileSize() %9cqJ]S  
{ r]xdhR5  
int nFileLength = -1; s'_$j$1  
try{ _6| /P7"  
URL url = new URL(siteInfoBean.getSSiteURL()); s-y'<(ll  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  z, :+Oc  
httpConnection.setRequestProperty("User-Agent","NetFox"); $d
5&~I  
]q@rGD85K  
7?)m(CFy  
int responseCode=httpConnection.getResponseCode(); )bF)RLZ  
if(responseCode>=400) if\k[O 1T6  
{ &Qz"nCvJ  
processErrorCode(responseCode); 48W:4B'l9  
return -2; //-2 represent access is error /o~ @VF:  
} Di]Iy  
>f3k3XWRT  
-{.h\  
String sHeader; REeD?u j  
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for(int i=1;;i++) oo"JMD)  
{ us(sZG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); kemr@_  
//Utility.log(in.readLine()); H7 o$O  
sHeader=httpConnection.getHeaderFieldKey(i); IiQWs1  
if(sHeader!=null) k)o7COx  
{ 2-/YYe;C  
if(sHeader.equals("Content-Length")) }d$vcEI$3  
{ (2&K(1.Y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $=QNGC2+  
break; jCdZ}M($  
} 9QO!vx  
} a?f5(qW3  
else mk$Yoz  
break; X*D5y8<  
} Z.Lx^h+U  
} WcQZFtW  
catch(IOException e){e.printStackTrace ();} #<^/yoH7C6  
catch(Exception e){e.printStackTrace ();} uugzIV)  
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Utility.log(nFileLength); C:TuC5Sr  
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return nFileLength; 9e|{z9z[l  
} 7zi^{]  
s7X~OF(#  
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//保存下载信息（文件指针位置） M<hs_8_*  
private void write_nPos() bDcWb2lqs  
{ JRcuw'8+q  
try{ Fb$5&~d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gPn%`_d5  
output.writeInt(nStartPos.length); 4B%5-VQ  
for(int i=0;i<nStartPos.length;i++) 8=b{'s^^F  
{ A@lhm`Aa  
// output.writeLong(nPos); zYNM<W;  
output.writeLong(fileSplitterFetch.nStartPos); ` Mv5!H5l  
output.writeLong(fileSplitterFetch.nEndPos); -+Awm{X_@  
} j/; @P  
output.close(); pU\xzLD  
} '8((;N|I^  
catch(IOException e){e.printStackTrace ();} }*{\)7g  
catch(Exception e){e.printStackTrace ();} UeC%Wa<[  
} P+D|_3j  
#z1ch,*3;  
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//读取保存的下载信息（文件指针位置） G> 5=`  
private void read_nPos() z.\[Va$@l  
{ 8EVF<@{]  
try{ }(hYG"5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *=KexOa9  
int nCount = input.readInt(); '44nk(hM69  
nStartPos = new long[nCount]; tS*^}e*  
nEndPos = new long[nCount]; bsmoLT  
for(int i=0;i<nStartPos.length;i++) [ a65VR~J  
{ RF\1.HJG  
nStartPos = input.readLong(); oVxV,oH(  
nEndPos = input.readLong(); tkUW)ScJ  
} y}H*p  
input.close(); Y+Q
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} ~,3v<A[5Vi  
catch(IOException e){e.printStackTrace ();} a#
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catch(Exception e){e.printStackTrace ();} y("0Xve  
} n?KS]ar>  
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private void processErrorCode(int nErrorCode) \!4ghev3  
{ ?yd(er<_f  
System.err.println("Error Code : " + nErrorCode); 9_CA5?y$:  
} 4<K ,w{
I  
LMhY"/hAXa  
j#.-MfB  
//停止文件下载 D;T r  
public void siteStop() FZ'>LZ  
{ PY3V
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bStop = true; yvH#1F`{q  
for(int i=0;i<nStartPos.length;i++) %<#$:Qb.  
fileSplitterFetch.splitterStop(); sD8xH  
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} ,BN}H-W\2  
} 9"u@<]  
//负责部分文件的抓取 C`K9WJOD  
**FileSplitterFetch.java qjRiTIp9q  
*/ :4L5@>b-  
package NetFox; ztxQv5=:,  
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import java.io.*; h"Yqm"U/  
import java.net.*; N#6A>  
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public class FileSplitterFetch extends Thread { H?r;S 5)c  
F|3FvxA  
)9sr,3w  
String sURL; //File URL K+TTYQ  
long nStartPos; //File Snippet Start Position 1Mhc1MU  
long nEndPos; //File Snippet End Position {II7%\ya  
int nThreadID; //Thread's ID YF[!Hpzq  
boolean bDownOver = false; //Downing is over SO jDtZ  
boolean bStop = false; //Stop identical HjY-b*B  
FileAccessI fileAccessI = null; //File Access interface 7g<`wLAH  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
0bQiUcg/  
{ QCY{D@7T  
this.sURL = sURL; So]FDd  
this.nStartPos = nStart; NS/L! "g  
this.nEndPos = nEnd; nO7o7bc  
nThreadID = id; D+U/]sW  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 y&I|m  
} X52jqXjg  
4lKbw4[a  
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public void run() _"t.1+-K  
{ 4R^j"x 5  
while(nStartPos < nEndPos && !bStop) R*5;J`TW  
{ 0tL/:zID  
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try{ )p_LkX(  
URL url = new URL(sURL); ^~IcQ!j/5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /gy:#-2Gy  
httpConnection.setRequestProperty("User-Agent","NetFox"); _!g NF=  
String sProperty = "bytes="+nStartPos+"-"; >w
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httpConnection.setRequestProperty("RANGE",sProperty); u~T$F/]k>  
Utility.log(sProperty); i3W
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InputStream input = httpConnection.getInputStream(); Ch!Q?4  
//logResponseHead(httpConnection); |+=:x]#vV  
9@EnmtR  
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byte[] b = new byte[1024]; (C_
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int nRead; K#
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /!uBk3x:  
{ 5dEO_1q %  
nStartPos += fileAccessI.write(b,0,nRead); (tz]!Aa{s  
//if(nThreadID == 1) 7T;RXrT  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n&78~@H  
} X@4d~6k?  
F`}w0=-*(  
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Utility.log("Thread " + nThreadID + " is over!"); : MmXH&yR  
bDownOver = true; -
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//nPos = fileAccessI.write (b,0,nRead); 12DdUPOi  
} nMvIL2:3  
catch(Exception e){e.printStackTrace ();} B148wh#r  
} BW\5RIWwE5  
} .W.U:C1  
67:<X(u+!  
!Jp.3,\?~  
//打印回应的头信息 #UN{ J6{  
public void logResponseHead(HttpURLConnection con) 2EcYO$R!  
{ +VCo=oA  
for(int i=1;;i++) D>^ix[:J  
{ Sqt"G6<  
String header=con.getHeaderFieldKey(i); 3E@&wpj  
if(header!=null) %+"AF+c3r  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kGeME   
Utility.log(header+" : "+con.getHeaderField(header)); utS Mx(  
else ?vNS!rY2&  
break; s H[34gCh;  
} ~{!!=@6  
} RtM.}wv;  
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public void splitterStop() &WU*cfJn)A  
{ gUtbCqDS  
bStop = true; rAdcMFW  
} 7B2Og{P  
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} VQ3&  
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/* *,*5sV  
**FileAccess.java Y }d>%i+  
*//文件访问(定位，写) g*AqFY7|  
package NetFox; :6iq{XV^  
import java.io.*; &4iIzw`  
Bq8<FZr#!  
8+|Lph`/?  
public class FileAccessI implements Serializable{ Kg67cmj)f  
dju{&wo~4  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 FKm2slzb  
RandomAccessFile oSavedFile; "t`e68{Ls  
long nPos; u[qtuM?&  
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public FileAccessI() throws IOException ~WLsqP5Y~a  
{ U]3JCZ{]0E  
this("",0); Bv*h?`Q  
}  \hc9Rk  
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!
 
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public FileAccessI(String sName,long nPos) throws IOException o#b9M4O  
{ Vi-@z;k  
oSavedFile = new RandomAccessFile(sName,"rw"); [_Z3v,vt,  
this.nPos = nPos; (dZ&Af  
oSavedFile.seek(nPos); T^SOq:m&  
} PrxX
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public synchronized int write(byte[] b,int nStart,int nLen) dGN*K}5  
{ ]7@Dqd-/S  
int n = -1; |Dli6K
N  
try{ pqX=l%{4ES  
oSavedFile.write(b,nStart,nLen); b5C #xxIO  
n = nLen; VgL<uxq  
} r]{:{Z  
catch(IOException e) tzPe*|m<  
{ wEyh;ID3#  
e.printStackTrace (); [c~zO+x  
} J{I?t~u  
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2Hj]QN7"   
return n; )VrHP9fu  
} I115Rp0  
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} YTsn;3d]}  
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/* [;
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**SiteInfoBean.java xNU}uW>>T  
*/ 0jMrL\>C  
package NetFox; Ns{4BM6j  
4BX*-t  
IFe[3mB5  
public class SiteInfoBean { -#h \8Xl  
eS M!_2  
u5,<.#EVY  
private String sSiteURL; //Site's URL JM0)x}]+  
private String sFilePath; //Saved File's Path _Yv9u'q"  
private String sFileName; //Saved File's Name J<D =\  
private int nSplitter; //Count of Splited Downloading File 3@SfCG&|e  
yuWrU<Kw  
! >V1zk  
public SiteInfoBean() NaIVKo  
{//nSplitter的缺省值为5 3dfSu'  
//default value of nSplitter is 5 +{&g|V  
this("","","",5); L[efiiLh$  
} p*G_$"KpP  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z]dc
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{ pVM;xxJ  
sSiteURL= sURL; $U1'n@/J  
sFilePath = sPath; ^;e`ZtcI  
sFileName = sName; /on p<u  
this.nSplitter = nSpiltter; Fwtwf{9I  
~Km8-b(&  
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} `1dr$U  
[dUEe@P  
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public String getSSiteURL() :Li)]qN.I  
{ e3.TGv7=  
return sSiteURL; H}X"yLog*  
} qH$p]+Rk 5  
1Pbp=R/7ar  
.(krB%N  
public void setSSiteURL(String value) <qu\q \  
{ UqH7ec  
sSiteURL = value; G{<wXxq%  
} E[y?\{  
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afjC~}  
public String getSFilePath() x!J L9  
{ &,+ZNA`P  
return sFilePath; 'W)x<Iey1  
} %rYt; 7B  
Mg].#  
iV%%VR8b  
public void setSFilePath(String value) !eW<4jYB  
{ a2zo_h2R  
sFilePath = value; %(i(ZW "  
} AdhCC13B  
IkupW|}rc  
V6c?aZ,O  
public String getSFileName() #RcmO*
*  
{ q?6Zu:':  
return sFileName; jU=)4nx  
} drH!?0Dpg  
}I]9I _S  
][.1b@)qV  
public void setSFileName(String value) @Q'5/q+  
{ Jv5G:M5+~  
sFileName = value; E3'6lv'  
} aw~OvnX E  
p47~vgJN  
fK[9<"PC0  
public int getNSplitter() kG{(Qi  
{ kb>9;-%^JK  
return nSplitter; g&"Nr aQM9  
} TYp{nWwi  
PUI.Un2C_  
*J6qL! ["  
public void setNSplitter(int nCount) E-RbFTVBA  
{ U+W8)7bc  
nSplitter = nCount; /c09-$M  
} dX<UruPA  
} (7"qT^s3  
i"r=b%;;  
='s2S5#1  
/* G|o-C:~  
**Utility.java &" b0`&l  
*/ Lbd_L  
package NetFox; G"'DoP7p9  
?[kO= hs  
A!NT 2YdHZ  
public class Utility { C~ >'pS6%5  
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public Utility() &c A?|(7-  
{ u*"tZ+|m  
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} pt=[XhxC(>  
H94$Xi"Bd
 
//线程睡眠 9[:nWp^  
public static void sleep(int nSecond) /wmJMX  
{ 9t=erhUr  
try{
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Thread.sleep(nSecond); 4*'NpqC(_  
} H~ (I  
catch(Exception e) "<=^Sm  
{ bju0l[;=  
e.printStackTrace (); S6cSeRmw  
} I@.qon2V  
} KExfa4W 3{  
&%^[2^H8"  
//日志 z8A`BVqI  
public static void log(String sMsg) 6~
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{ 7%JXVP}A  
System.err.println(sMsg); =uD2j9!"7  
} $WdZAv\_S  
lVMAab  

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public static void log(int sMsg) LV`- eW  
{ E]Kd`&^}  
System.err.println(sMsg); 7m8L!t9  
} d8|:)7PSt  
} Xa-]+_?Q  
)U8F6GIC&}  
|]Ockg[
  
/* k/Cr ^J"  
**TestMethod.java .3$iOMCH  
*/ zS.7O'I<'  
package NetFox; ZWYwVAo  
d`^j\b>5(  

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public class TestMethod { H.'_NCF&;L  
Lc+)#9*d  
-6#i~a]  
public TestMethod() /Z\zB  
{ ///xx/weblogic60b2_win.exe I_v]^>Xw  
try{ 0\u_\%[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F*}b),  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3<B{-z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <;M6s~  
fileFetch.start(); &u$l2hSS  
} |IZG`
3  
catch(Exception e){e.printStackTrace ();}  c,x2  
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xOP\ +(  
} tw^V?4[Miu  
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public static void main(String[] args) ~ 5`Ngpp  
{ D7 A{*Tm  
new TestMethod(); I9B B<~4o  
} Bojm lVg  
} r)ga{Nn,.  
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