http断点续传简单实现（java)

/* Ut0oh  
**SiteFileFetch.java $2\OBc=  
*/ qL]!/}  
package NetFox; 2y,f  
import java.io.*; \|Us/_h  
import java.net.*; O$KLQ'0"n  
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public class SiteFileFetch extends Thread { r 5:DIA!  
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SiteInfoBean siteInfoBean = null; //文件信息Bean XZ}]H_, n  
long[] nStartPos; //开始位置 w8c71C  
long[] nEndPos; //结束位置 %r?Y!=0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7]62=p2R  
long nFileLength; //文件长度 #T&''a  
boolean bFirst = true; //是否第一次取文件 0)+F}SyyD  
boolean bStop = false; //停止标志 gm(`SC?a  
File tmpFile; //文件下载的临时信息 P @G2F:}  
DataOutputStream output; //输出到文件的输出流 R>yoMk/u  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） T5Yu+>3  
public SiteFileFetch(SiteInfoBean bean) throws IOException KHI-m9(  
{ zXIVHC,"{  
siteInfoBean = bean; VPet1hAy  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); bU7n1pzW,o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ol[   
if(tmpFile.exists ()) !T!U@e=u  
{ xhWWl(r`5  
bFirst = false; u%}zLwMH  
read_nPos(); :H@Q`g u  
} RNiFLD%5  
else GU([A@;  
{ zT 9"B  
nStartPos = new long[bean.getNSplitter()]; 7'LKyy !"3  
nEndPos = new long[bean.getNSplitter()]; WRe9ki=R  
} % tTL  
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Y({&}\o  
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} iz.J._&  
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public void run() &s-iie$"@x  
{ !:]CKbG  
//获得文件长度 Cjc>0)f&.  
//分割文件 +`}QIp0  
//实例FileSplitterFetch ibAZ=
RD  
//启动FileSplitterFetch线程 Arc6d5Q  
//等待子线程返回 aA7}>  
try{ yS'W ss  
if(bFirst) }>]V_}h  
{ P%2aOsD0  
nFileLength = getFileSize(); m<}>'D
T  
if(nFileLength == -1) 6#hDj_(,  
{ IOhJL'r  
System.err.println("File Length is not known!"); UuPXo66F]  
} V"K-aO&  
else if(nFileLength == -2) XYj!nx{k,  
{ ])`w_y(>  
System.err.println("File is not access!"); 5$$Yce=k  
} ]{^'{z$i  
else :7>oFz  
{ 42]
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for(int i=0;i<nStartPos.length;i++) T+1:[bqK  
{ xq$(=WPI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `ECY:3"$KA  
} {%Cb0Zh  
for(int i=0;i<nEndPos.length-1;i++) Vq-W|<7C=  
{ w`KqB(36  
nEndPos = nStartPos[i+1]; Lz6b9W  
} F#-mseKhc  
nEndPos[nEndPos.length-1] = nFileLength; /Z^"[Ke  
} [J{\Ke0<e1  
} Bie#GKc  
=>3wI'I  
#0kVhx7%  
//启动子线程 !:Z lVIA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >-oB%T
 
for(int i=0;i<nStartPos.length;i++) e<A6=}  
{ wr5ScsNS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2S,N9(7  
nStartPos,nEndPos,i); -+ylJo[D  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C-h9_<AwJQ  
fileSplitterFetch.start(); ;YN`E  
} ] MP*5U>;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b'r</ncZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); LY:%k|L9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H1Jk_@b  
nEndPos = " + nFileLength); G`D rY;  
// fileSplitterFetch[nPos.length-1].start(); x%_VzqR`  
= y@*vl   
aQ.QkMZ  
//等待子线程结束 RW-)({  
//int count = 0; c~``)N  
//是否结束while循环 f4 k  
boolean breakWhile = false; amTeTo]Tg  
.q90+9Ek=  
FP=up#zl  
while(!bStop) ,ArHS  
{ qPQ6`rD\  
write_nPos(); Nwwn #+  
Utility.sleep(500); %cO^:  
breakWhile = true; ~ECIL7,  
kz_gR;"(Z  
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for(int i=0;i<nStartPos.length;i++) M}fk[Yr>  
{ $-=xG&fSz  
if(!fileSplitterFetch.bDownOver) B%7Az!GX  
{ / f5q9sp8  
breakWhile = false; }]#&U
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break; |lCS^bA3  
} 5bB\i79$  
} &x9>8~   
if(breakWhile) &2,3R}B/  
break; .
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^r
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'kOkwGf!  
//count++; %1oB!+tv  
//if(count>4) u4#YZOiY)A  
// siteStop(); y'5`Uo?\",  
} 6o0}7T%6  
&t~NR$@  
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System.err.println("文件下载结束！"); n1U!od  
} n!dXjInV  
catch(Exception e){e.printStackTrace ();} T>hrKn.!D:  
} aPdEEqc\l  
{j6$'v)0  
3Ofh#|qc&  
//获得文件长度 u\{MQB{T  
public long getFileSize() Wsb>3J  
{ 25PZ&^G8%  
int nFileLength = -1; v,'k2H  
try{ ;kI)j ?  
URL url = new URL(siteInfoBean.getSSiteURL()); 4Ei8G]O $_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t[r6jo7  
httpConnection.setRequestProperty("User-Agent","NetFox"); Sa[?B  
=X1oB,W{  
9a2[_Wy  
int responseCode=httpConnection.getResponseCode(); XJ!?>)N .  
if(responseCode>=400) )1f%kp#]  
{ Z9G4in8  
processErrorCode(responseCode); G|oO  
return -2; //-2 represent access is error /a*8z,x  
} .p=OAh<  
SBy{sbx4&F  
F EUfskv  
String sHeader; AGl#f\_^  
/X]gm\x7s  
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for(int i=1;;i++) /Y=_EOS  
{ s3Wjhw/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j0=F__H#@  
//Utility.log(in.readLine()); 9u)p9)^-.v  
sHeader=httpConnection.getHeaderFieldKey(i); `Ez8!d{MD8  
if(sHeader!=null) Hu9nJ  
{ <0VC`+p<)  
if(sHeader.equals("Content-Length")) xw}rFY$  
{ bl
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); H&8~"h6n  
break; s#'Vasu  
} 8BrC@L2E0  
} GEvx<:  
else 1s~rWnhVv  
break; u/<ZGW(&s(  
} !</U"P:L  
} kbL7Xjk  
catch(IOException e){e.printStackTrace ();} deQ{  
catch(Exception e){e.printStackTrace ();} b# Dd  
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Utility.log(nFileLength); ow  
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return nFileLength; P*jiz@6  
} u -)ED  
@3y >|5Y  
q:nUn?zB  
//保存下载信息（文件指针位置） 3ZC@q #R A  
private void write_nPos() ,Ne9x\F  
{ (t){o>l  
try{ # >I_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :@@`N_2?  
output.writeInt(nStartPos.length); =jKu=!QPq  
for(int i=0;i<nStartPos.length;i++) 15VvZ![$V  
{ _u""v   
// output.writeLong(nPos); ,na}' A@a`  
output.writeLong(fileSplitterFetch.nStartPos); yN)(MmX'1  
output.writeLong(fileSplitterFetch.nEndPos); 2}7_Y6RS*  
} _k :BY  
output.close(); '4It>50b  
} ePZ
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catch(IOException e){e.printStackTrace ();} 'gXD?ARW  
catch(Exception e){e.printStackTrace ();} ]&;In,z  
} TQ:h[6v  
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//读取保存的下载信息（文件指针位置） uF|Up]Z G  
private void read_nPos() kOdA8XRY  
{ "uP*pR^  
try{ -[J4nN&N  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); RX%)@e/@  
int nCount = input.readInt(); nGwon8&]]
 
nStartPos = new long[nCount]; U.V/JbX
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nEndPos = new long[nCount]; 3#x1(+c6
 
for(int i=0;i<nStartPos.length;i++) m]*a;a'}#  
{ Niu |M@  
nStartPos = input.readLong(); N p*T[J  
nEndPos = input.readLong(); vz#-uw,O:  
} .%dGSDru  
input.close(); Lagk   
} ;&gk)w6*  
catch(IOException e){e.printStackTrace ();} 4%zy$,|e  
catch(Exception e){e.printStackTrace ();} Pwj|]0Y@  
} S(U9Dlyarg  
#>HY+
;  
~ o2Z5,H  
private void processErrorCode(int nErrorCode) j/Y]3RSMp  
{ WVsj  
System.err.println("Error Code : " + nErrorCode); =L@CZ"  
} j!kJ@lbP  
 zR'EQ  
0'THL%lK  
//停止文件下载 <KK.f9^o(  
public void siteStop() x_I*6?  
{ #_x5-?3  
bStop = true; Xn?.Od(  
for(int i=0;i<nStartPos.length;i++) `1n^~  
fileSplitterFetch.splitterStop(); Qd\='*:!  
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n_rpT.[  
} 1_Ks*7vuq  
} PNd'21N  
//负责部分文件的抓取 Aqmw#X  
**FileSplitterFetch.java O9-`e  
*/ aeI0;u  
package NetFox; \2=I//YF  
m&b1H9ymd  
h_ccE6]t  
import java.io.*; A`JE(cIz3  
import java.net.*; 2LR y/ah  
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public class FileSplitterFetch extends Thread { X`EVjK  

7]{t^*  
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String sURL; //File URL J_7@d]0R  
long nStartPos; //File Snippet Start Position CshME\/  
long nEndPos; //File Snippet End Position xo?'L&%  
int nThreadID; //Thread's ID V=5S=7 Z:  
boolean bDownOver = false; //Downing is over cr<j<#(Z}  
boolean bStop = false; //Stop identical Y3~z#<  
FileAccessI fileAccessI = null; //File Access interface K?[Vz[-Fc  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException AG}j'   
{ BfCM\ij  
this.sURL = sURL; ,`Z4fz:  
this.nStartPos = nStart; gE$Uv*Gj  
this.nEndPos = nEnd; rr2!H%:
 
nThreadID = id; <`"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 z/h]Jos  
} GDC@s<[k  
@[?ZwzY:9  
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public void run() jIr\.i  
{ Q0Do B  
while(nStartPos < nEndPos && !bStop) ^`iz%^  
{ R4VX*qkB  
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try{ ,SNrcwv  
URL url = new URL(sURL); Ipq0 1 +  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )`{m |\b  
httpConnection.setRequestProperty("User-Agent","NetFox"); xM!9$v  
String sProperty = "bytes="+nStartPos+"-"; !4D?X\~"%  
httpConnection.setRequestProperty("RANGE",sProperty); _b/zBF
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Utility.log(sProperty); Jnd_cJ]a  
.tGz,z}  
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InputStream input = httpConnection.getInputStream(); LQr
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//logResponseHead(httpConnection); RCYv2=m>Q  
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byte[] b = new byte[1024]; I}o} #OJ  
int nRead; L~)8Q(f  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) QICxS
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{ B+~ /-3  
nStartPos += fileAccessI.write(b,0,nRead); c1i:m'b_5  
//if(nThreadID == 1) VpYD/Oj4;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r5UVBV8T  
} OomC%9/=,  
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Utility.log("Thread " + nThreadID + " is over!"); T30fp  
bDownOver = true; s@"|o3BX  
//nPos = fileAccessI.write (b,0,nRead); \b$pH  
} Ssz;d&93  
catch(Exception e){e.printStackTrace ();} "P@ SR`v#  
} w0Nm.=I-   
} ,D*bLXWh  
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//打印回应的头信息 &v*4AZ['  
public void logResponseHead(HttpURLConnection con) Ns1n|^9  
{ et~D9='E  
for(int i=1;;i++) K-\wx5#l/  
{ b?KdR5  
String header=con.getHeaderFieldKey(i); )\:IRr"  
if(header!=null) T:'JA
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5yK#;!:h  
Utility.log(header+" : "+con.getHeaderField(header)); d9U)O6=  
else kZF<~U  
break; CUG"2K9  
} /bo=,%wJ[  
} ;A@DE@^5w  
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public void splitterStop() jlF3LK)9q  
{ }ri
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bStop = true; G%l')e)9Gq  
} j7Y7&x"  
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} c CDT27@  
|5dNJF8;Q  
6Y\TVRR  
/* =`|BofR  
**FileAccess.java Gvdok<o  
*//文件访问(定位，写) /
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package NetFox; :vEfJSA 1<  
import java.io.*; #"!ga)a%L  
Q<D_QJ  
-(WRhBpw  
public class FileAccessI implements Serializable{ Kn1;=k  
L)\<7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 'Z.C&6_  
RandomAccessFile oSavedFile; Zqe$S +u  
long nPos; f1'X<VA  
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public FileAccessI() throws IOException /0gr?I1wr7  
{ 2bw), W  
this("",0); xSM1b5=Pu  
} nj;3U^  
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public FileAccessI(String sName,long nPos) throws IOException 9)S3{i6w  
{ ^{=UKf{  
oSavedFile = new RandomAccessFile(sName,"rw"); V[*>}XQER  
this.nPos = nPos; =8`KGeP$  
oSavedFile.seek(nPos); "62g!e}!c  
} Z&iW1  
YuVlD/  
s#a`e]#
?  
public synchronized int write(byte[] b,int nStart,int nLen) +HUy,@^Pa  
{ B/@LE{qUn  
int n = -1; Xgn
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try{ LprGsqr:  
oSavedFile.write(b,nStart,nLen); 3w |5%`  
n = nLen; @73kry v  
} `kvIw,c.  
catch(IOException e) {Y2J:x  
{ LVdR,'lS  
e.printStackTrace (); (2Lmu[  
} 3o>JJJ=]  

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return n; -eh .Tk  
} L;M@]  
s1::\&`za  
)i:*r8*~  
} O#[bNLV  
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/* +UX~
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**SiteInfoBean.java <+ [N*  
*/ B?^~1Ua9Zv  
package NetFox; J;wB
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l"`VvW[  
public class SiteInfoBean { n!8W@qhew  
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Btzes.  
private String sSiteURL; //Site's URL 8pr toCB  
private String sFilePath; //Saved File's Path ^;s/4  
private String sFileName; //Saved File's Name 3`{ vx  
private int nSplitter; //Count of Splited Downloading File rloxM~7!,)  
j<BRaT  
GLZ*5kw  
public SiteInfoBean() NhNd+SCZ@  
{//nSplitter的缺省值为5 pnp8`\cIH  
//default value of nSplitter is 5 p&<n_b  
this("","","",5); CC3i@  
} D8~\*0->  
)h0>e9z>Y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [
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{ GKF!GbGR@  
sSiteURL= sURL; 8O{V#aop  
sFilePath = sPath; k1yqerA  
sFileName = sName; IOC$jab@  
this.nSplitter = nSpiltter; `5Z'8^  
V?.=_T<  
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} cc`u{F9  
/&47qU4PJ  
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public String getSSiteURL() >vXJ9\  
{ [) >Yp-n  
return sSiteURL; C}3a^j  
} l4taD!WD/  
z(.,BB[  
^["D>@yIR  
public void setSSiteURL(String value) s.;'-oA  
{ nr&|  
sSiteURL = value; wexX|B^u  
} [Rq|;p  
II _CT=  
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public String getSFilePath() Ce}m$k  
{ VE*`Ji  
return sFilePath; tQT<1Q02i  
} baTd;`Pn  
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public void setSFilePath(String value) 9mXmghoCO  
{ vyWx{@  
sFilePath = value; 1uKIO{d@  
} ,+h<qBsV@  
>jTiYJI_M  
rc>}3?o  
public String getSFileName() 1/ j>|  
{ (gvnIoDl0  
return sFileName; 3"my!}03  
} NW;_4g4qE  
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public void setSFileName(String value) 1TfFWlf[B  
{ =Xid"$  
sFileName = value; Oi~Dio_?  
} `S?_=JIX  

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public int getNSplitter() jJvd!,=)  
{ D_ej%QtB@  
return nSplitter; )`Qr=DIsW  
} #fx"tx6  
>
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public void setNSplitter(int nCount) =I&BO[d  
{ A/lznBHR  
nSplitter = nCount; lF46W  
} [z7]@v6b  
} z,dFDl$  
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x+%> 2qgj"  
/* NaQ~iY?  
**Utility.java OaoHN& "  
*/ *Ev8f11i&  
package NetFox; d0%Wz5Np  
4~oRcO8!Y  
=1!.g"0  
public class Utility { wM;=^br  
gwB0/$!4"  
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public Utility() #ifjQ7(:  
{ wNFx1u^/)  
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}9z$72;Qdq  
} u9c^YCBM  
t(.vX  
//线程睡眠 l`X?C~JhJ  
public static void sleep(int nSecond) r~,3  
{ 9]G~i`QQ  
try{ vGJw/ij'X  
Thread.sleep(nSecond); E"/k"1@  
} ZtGkMd$  
catch(Exception e) B 'd@ms  
{ bng/v  
e.printStackTrace (); /Gb)BJk!  
} }LEasj  
} Lew 2Z
 
7NvRZ!  
//日志 |VyN>
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public static void log(String sMsg) B'vIL'  
{ 1Zo3
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System.err.println(sMsg); 5O
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} 0d~?|Nv -  
/a-s9<  
3aU4Z|f~  
public static void log(int sMsg) !T~uxeZ/;  
{ md\Vw?PkU  
System.err.println(sMsg); D=5%lL  
} c5KciTD^  
} w'xPKO$bzR  
1guiuR4  
s{Y-Vdx  
/* DmB?.l-  
**TestMethod.java hS%oQ)zvE  
*/ lPA}06
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package NetFox; q!5`9u6  
@K#}nKN'  
6*|EB|%n  
public class TestMethod { ose)\rM'  
w#L`|cYCm  

L1@<7?@X  
public TestMethod() 7}&vEc@w&  
{ ///xx/weblogic60b2_win.exe _a`/{M|  
try{ <{Rz1CMc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {[{jlG4H  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ka_R|xG\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Fs=E8'
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fileFetch.start(); l u{6  
} M4d4b  
catch(Exception e){e.printStackTrace ();} :V)=/mR  
):L0{W{  
(J(SwL|  
} YXU2UIY<~  
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] J|#WtS  
public static void main(String[] args) !\Xrl) $j{  
{ $c+:dO|Fb  
new TestMethod(); wwa)VgoS[  
} tjne[p  
} ojIGfQV  
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