http断点续传简单实现（java)

/* r
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**SiteFileFetch.java NW;_4g4qE  
*/ Y^d#8^cP  
package NetFox; +.^pAz U}R  
import java.io.*; 4)}>dxv  
import java.net.*; VFnxj52<  
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M3!;u%~}s  
public class SiteFileFetch extends Thread { G[>CBh5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean @~7au9.V=X  
long[] nStartPos; //开始位置 =
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long[] nEndPos; //结束位置 ! ,H6.IH;S  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1\/vS$bi(  
long nFileLength; //文件长度 "^{Hta  
boolean bFirst = true; //是否第一次取文件 >
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boolean bStop = false; //停止标志 IS[q'Cv*  
File tmpFile; //文件下载的临时信息 "B"ql-K  
DataOutputStream output; //输出到文件的输出流 ,+v(?5[6  
x@O)QaBN!  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） lF46W  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^jpQfDe6  
{ iDgc$'%?  
siteInfoBean = bean; z$g__q-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y!S:d
  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); = 4|"<8'  
if(tmpFile.exists ()) 4T$jY}U  
{ 6q0)/|,@  
bFirst = false;  4y5Q5)j  
read_nPos(); S_??G:i  
} x+'Ea.^  
else kDQE*o  
{ !,b&e  
nStartPos = new long[bean.getNSplitter()]; MZX@Gi<S[  
nEndPos = new long[bean.getNSplitter()]; -cn`D2RP  
} {H9
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,.=7{y~  
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} u9c^YCBM  
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public void run() AhjCRYk+  
{ g.8^ )u  
//获得文件长度 =)iAU/*N  
//分割文件 *YQXxIIq  
//实例FileSplitterFetch
;8e}X6YU  
//启动FileSplitterFetch线程 %g>k0~TRf#  
//等待子线程返回 /yUKUXi  
try{ /9D mK%d  
if(bFirst) (&V*~OR  
{ l;aO"_E1m  
nFileLength = getFileSize(); j2:9ahW  
if(nFileLength == -1) QGErQ +l  
{ |vG?H#y  
System.err.println("File Length is not known!"); ehe#"exCB  
} n1R{[\ >1  
else if(nFileLength == -2) w9gfva$&  
{ (otD4VR_  
System.err.println("File is not access!"); T|(w-)mv  
} y6G6wk;  
else O_ $zK  
{ Yyw3+3
 
for(int i=0;i<nStartPos.length;i++) j#p3<V S4  
{ 23bTCp.d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); DI-CC[  
} 4QiV@#o:  
for(int i=0;i<nEndPos.length-1;i++) .ubZ  
{ pf yJL?_%  
nEndPos = nStartPos[i+1]; 81I9xqvSd~  
} hHOx ]  
nEndPos[nEndPos.length-1] = nFileLength; *'{9(Oj  
} EQHCw<e  
} G-vkkNj%e  
&f)pU>Di  
G/(tgQ  
//启动子线程 Ne1W!0YLK  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; aE:$ N#|Qa  
for(int i=0;i<nStartPos.length;i++) Wn2J]BH  
{ ka_R|xG\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dg0WH_#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H~ >\HV*  
nStartPos,nEndPos,i); Tz\v.&? $  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q;m8 drU  
fileSplitterFetch.start(); ?c fFJl  
} &RHx8zScP  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K\lu;   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); zE}ry!{  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <]`|HJoy  
nEndPos = " + nFileLength); ,n>K$  
// fileSplitterFetch[nPos.length-1].start(); d:z7 U  
6s
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//等待子线程结束 bNvc@oo  
//int count = 0; ej(< Le\  
//是否结束while循环 `'bu8JK  
boolean breakWhile = false; 1u }2}c|  
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while(!bStop) "p>kiNu  
{ $ 93j;  
write_nPos(); b'`C<Rk  
Utility.sleep(500); /}d)g4\j  
breakWhile = true; H$zDk  
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eh
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for(int i=0;i<nStartPos.length;i++) b0N7[M1Xl  
{ h?->A#  
if(!fileSplitterFetch.bDownOver) QbWeQ[V{  
{
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breakWhile = false; j4#S/:Q<7  
break; mJVru0  
} ]qk`Yi  
} Q$yQ^ mG  
if(breakWhile) Qgo|\=  
break; W{]r_`=:6S  
m='_O+ $  
OZ<fQf.Gh}  
//count++; B/JMH 1r  
//if(count>4) +KP&D.wIo  
// siteStop(); 2>^jMln  
} 97}l`z;Z  
*44E'Dxv  
O%} hNTS"  
System.err.println("文件下载结束！"); @< 0c  
} S'IQbH
z*  
catch(Exception e){e.printStackTrace ();} 5~i}!n  
} Ui"3'OU'  
i)]^b{5nyB  
9N<TJp,q  
//获得文件长度 H"pwIiC  
public long getFileSize() %e/L .#0  
{ _+0c<'  
int nFileLength = -1; Z
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try{ u6*0% Km  
URL url = new URL(siteInfoBean.getSSiteURL()); rGQ([e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); GM0pHmC  
httpConnection.setRequestProperty("User-Agent","NetFox"); tRTJQ  
;,@Fz  
YJZ`Clp?  
int responseCode=httpConnection.getResponseCode(); _J_QB]t  
if(responseCode>=400) L^ U.h  
{ aq^OzKP?  
processErrorCode(responseCode); m9$lOk4/  
return -2; //-2 represent access is error iis}=i7|  
} Uee$5a>(  
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String sHeader; 5^{).fig  
#\3X;{  
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for(int i=1;;i++) 0P4g6t}e  
{ N8{ 8 a  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )gxZ &n6  
//Utility.log(in.readLine()); 9u_D@A"aC`  
sHeader=httpConnection.getHeaderFieldKey(i); G4n-}R&'  
if(sHeader!=null) U/{#~P5s  
{ IG8I<+<o  
if(sHeader.equals("Content-Length")) !z+'mF?V+X  
{ -&LF`V&3w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); x0dBg~I  
break; .JWN\\  
} ~HUO$*U4<  
} D[K!xq  
else edfb7prfTl  
break;
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} 7hKfxw-X@  
} SJ&+"S&  
catch(IOException e){e.printStackTrace ();} S@WT;Q2Z  
catch(Exception e){e.printStackTrace ();} z3|5E#m  
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Utility.log(nFileLength); *V@t]d$=#  
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return nFileLength; FOSC#W9E  
} BvpUcICJ  
 0gJ{fcI  
ua%j
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//保存下载信息（文件指针位置） M4L<u,\1s  
private void write_nPos() V6^=[s R  
{ FND+Ok&  
try{ 5Ln !>,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )JA^FQ5N  
output.writeInt(nStartPos.length); 7k#0EhN1>  
for(int i=0;i<nStartPos.length;i++) UH7FIM7kX  
{ a)r
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// output.writeLong(nPos); =5 $BR<'  
output.writeLong(fileSplitterFetch.nStartPos); 3 E!F8GZ  
output.writeLong(fileSplitterFetch.nEndPos); )bB Va^  
} H:`H4S}  
output.close(); d+IN-lR(  
} 0@}:`OynX  
catch(IOException e){e.printStackTrace ();} F Xp_`9.zH  
catch(Exception e){e.printStackTrace ();} `s_k+ g  
} rTA#4.*&  
_>Oc>.MB  
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//读取保存的下载信息（文件指针位置） iY3TB|tMt  
private void read_nPos() S1_):JvV  
{ a}kPc}n\  
try{ 3q0S}<h al  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #i-b|J+%  
int nCount = input.readInt(); U{8x.
CJ]  
nStartPos = new long[nCount]; 7m;<b$  
nEndPos = new long[nCount]; )xYGJq4  
for(int i=0;i<nStartPos.length;i++) 0 TOw4pC  
{ &B} ,xcNO  
nStartPos = input.readLong(); '17V7A/t  
nEndPos = input.readLong(); Qa,$_,E  
} jFwJ1W;?-  
input.close(); vk|xYDD  
} ;% l0Ml>  
catch(IOException e){e.printStackTrace ();} _?;74VWA  
catch(Exception e){e.printStackTrace ();} \m~Oaf;$  
} <
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private void processErrorCode(int nErrorCode) O`0\f8/.?  
{ OBnvY2)Ri  
System.err.println("Error Code : " + nErrorCode); uB+:sX-L  
} \-{2E  
NnO%D^P]  
u~1 ,88&U  
//停止文件下载 .N Z  
public void siteStop() GBGna3  
{ r5PZ=+F  
bStop = true; HXQ }B$V  
for(int i=0;i<nStartPos.length;i++) >ToI$~84  
fileSplitterFetch.splitterStop(); Lv:;}  
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{R5_=MG  
} kQO5sX$;  
} DWk2=cO  
//负责部分文件的抓取 <ua! ]~  
**FileSplitterFetch.java .}iRe}=  
*/ MQlGEJ  
package NetFox; >xIb|Yp)&  
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c) _u^Dh  
import java.io.*; Twpk@2=l  
import java.net.*; }}4uLGu)  
i6xzHfaYG  
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public class FileSplitterFetch extends Thread { k3&/Ei5  
/=:Fw}vt  
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String sURL; //File URL e@g=wN"@  
long nStartPos; //File Snippet Start Position \N)!]jq  
long nEndPos; //File Snippet End Position ]N6
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int nThreadID; //Thread's ID fq !CB]C  
boolean bDownOver = false; //Downing is over -hZw.eChQa  
boolean bStop = false; //Stop identical ]t_ Wl1*|  
FileAccessI fileAccessI = null; //File Access interface Y|-:z@n6C  
|uM(A~?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,gIeQ!+vy  
{ lYy:A%yDT  
this.sURL = sURL; @[j%V ynf  
this.nStartPos = nStart; L.%zs  
this.nEndPos = nEnd; -;GB Xq  
nThreadID = id; )T'~F  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Nd**":i$  
} =Kt!+^\")  
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^'4I%L"  
public void run() -z>m]YDH  
{ SHqz&2u  
while(nStartPos < nEndPos && !bStop) Gc<^b  
{ L:Me  
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try{ qmq#(%Z <W  
URL url = new URL(sURL); BXUd i&'O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #kAk d-QY6  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?)e6:T(  
String sProperty = "bytes="+nStartPos+"-"; , 4@C%  
httpConnection.setRequestProperty("RANGE",sProperty); 4YCuO
%  
Utility.log(sProperty); 5 $.az  
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InputStream input = httpConnection.getInputStream(); /X?%K't2r  
//logResponseHead(httpConnection); ^*WO*f>y  
K#dG'/M|Pb  
@mEB=X(-l=  
byte[] b = new byte[1024]; |kqRhR(Ei  
int nRead; (YHK,aC>u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) k j&hn  
{ @Pf['BF"  
nStartPos += fileAccessI.write(b,0,nRead); 7h\U}!  
//if(nThreadID == 1) QX+&[G!DZH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dSbz$Fct  
} sUpSXG-W/@  
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Utility.log("Thread " + nThreadID + " is over!"); a-9sc6@  
bDownOver = true; W7.QK/@  
//nPos = fileAccessI.write (b,0,nRead); l:s
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} +e&Q<q!,q  
catch(Exception e){e.printStackTrace ();} f&C]}P  
} FUZ`ST+OL  
} aY\(R02B  
>;~ia3  
2jyxP6t  
//打印回应的头信息 &Pgk$e%>  
public void logResponseHead(HttpURLConnection con) R5fZ}C7  
{ sb</-']a  
for(int i=1;;i++) Fc a_(jw  
{ gr4JaV  
String header=con.getHeaderFieldKey(i); nT@FSt  
if(header!=null) I
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); EK
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Utility.log(header+" : "+con.getHeaderField(header)); i [6oqZ  
else 8lF:70wia  
break; ^\3z$ntF  
} 5>rjL;  
} 'UB"z{w%  
='<*mT<  
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public void splitterStop() -m Sf`1l0  
{ [.>g.p,;  
bStop = true; }dG>_/3  
} DK(8Ml:k  
`B7?F$J  
=[`gfw  
} ;>jOB>b{h  
XF9
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/* Z8WBOf*~e  
**FileAccess.java y(jd$GM|  
*//文件访问(定位，写) iU4Z9z!  
package NetFox; : W0;U  
import java.io.*; [)nU?l  
64f6D"."
 
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public class FileAccessI implements Serializable{ CMHg]la  
p\r V6+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 W";Po)YC  
RandomAccessFile oSavedFile; WRN}>]NgQ  
long nPos; GD#W=O  

{D4N=#tl  
/ 2h
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public FileAccessI() throws IOException L$=a,$  
{ ux>LciNq  
this("",0); TJkWL2r0c  
} qQCds}<w  
Z/b,aZhB  
B-tLRLWn   
public FileAccessI(String sName,long nPos) throws IOException ^-7-jZ@jz  
{ }Z% j=c"d  
oSavedFile = new RandomAccessFile(sName,"rw"); wW0m}L  
this.nPos = nPos; >TS=tK  
oSavedFile.seek(nPos); |=EwZmj-c  
} 1Ewg_/R  
~}s0~j~  
B{lL}"++0  
public synchronized int write(byte[] b,int nStart,int nLen) (t"rzH  
{ 5z"[{#/  
int n = -1; Ms=11C  
try{ (:|1h@K/R  
oSavedFile.write(b,nStart,nLen); "oT]_WHqo  
n = nLen; lsB.>NlU  
} PF:E{_~  
catch(IOException e) :6}cczQE|O  
{ ^tl&FWF  
e.printStackTrace (); 1:Xg&4s  
} !4mAZF b  
|@*   
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return n; RJLhR_t7n  
} jN2Xoh9  
()
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} Owm2/  
+c\uBrlZQ;  
YPS,[F'B.  
/* 8YkCTJfBGu  
**SiteInfoBean.java n|!O .+\b  
*/ T%1Kh'92  
package NetFox; H^8t/h  
q??N,  
Ox+}JB [  
public class SiteInfoBean { ( ALsc@K  
d$v{oC}  
8:}$L)[V  
private String sSiteURL; //Site's URL 3vF-SgCV  
private String sFilePath; //Saved File's Path " {Nw K  
private String sFileName; //Saved File's Name S{qn^\0  
private int nSplitter; //Count of Splited Downloading File "gq_^&  
L&qY709  
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public SiteInfoBean() [`=:uUf3  
{//nSplitter的缺省值为5 2%t!3F:  
//default value of nSplitter is 5 
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this("","","",5); 2Jn?'76`  
} f'B#h;`  
K yp(dp>  
{;?bC'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) v{TISgZ  
{ 1Yy*G-7}  
sSiteURL= sURL; DP4l %2m0  
sFilePath = sPath; 0/?=FM>  
sFileName = sName; `pYL/[5  
this.nSplitter = nSpiltter; 3Tr}t.mt  
,:"c"  
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} v*EErQML8b  
_@ @"'  
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public String getSSiteURL() Fj0h-7L  
{ }}~ t!/x  
return sSiteURL; w0$l3^}z  
} QD*(wj  
k0!D9tk  
*(]@T@yN  
public void setSSiteURL(String value) wvg>SfV,e  
{ S:xG:[N@  
sSiteURL = value; "=XRonQZ  
} -xc'P,`  
Q4&<RWbT^  
Qv:J#uVw?O  
public String getSFilePath() m4kUA"n5  
{ ^t
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return sFilePath; K9f7,/  
} %TRH,-@3h  
n"Q fW~U  
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public void setSFilePath(String value) Xu&4|$wB+  
{ MA5BTq<&  
sFilePath = value; 7(bE;(4  
} vCtag]H2@  
6d|%8.q1  
>,%7bq=T!  
public String getSFileName() .%N*g[J  
{ ppo\cy;  
return sFileName; jYJfo<  
} $)Pmr1==  
*`.4M)Ym~  
LjA>H>8%[  
public void setSFileName(String value) "M5&&\uT  
{ oFUP`p%[  
sFileName = value; (_O_zu8_  
} 9:jZ3U  
mbRN W  
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public int getNSplitter() sy.U]QG  
{ wXxk+DV@  
return nSplitter; ~",,&>#[K  
} )t$|'c}  
dsJHhsu6  
k!6wVJ|_Y  
public void setNSplitter(int nCount) ^YG.eT6iG  
{ Ws(#ThA  
nSplitter = nCount; 3Q"4-pd  
} S[W|=(f9  
} 1ssEJ;#s  
0q ^dpM  
+R?d6IjH  
/* _K"X  
**Utility.java Dx<CO1%z-  
*/ :X;AmLf`2u  
package NetFox; }];_ug* "  
^04|tda  
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public class Utility { -N[Q*;h|  
sw715"L  
+#!! 'XP  
public Utility() 5=--+8[ bV  
{ lj!f\C}d  
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} *"D8E^9  
enGjom  
//线程睡眠 Fv6<Cz6L  
public static void sleep(int nSecond) )gR !G]Y  
{ :h+gSvn:  
try{ X6dv+&=?  
Thread.sleep(nSecond); cQMb+Q2Yw  
} ard<T}|N  
catch(Exception e) \kGi5G]  
{ *rk!`n&  
e.printStackTrace (); Mo2b"A;}|  
} s) vHLf4T  
} 6M`N| %  
Q+\?gU]  
//日志 8Dq;QH}  
public static void log(String sMsg) 0FV?By  
{ LGm>x  
System.err.println(sMsg); -a[]#v9  
} v*7lJNN.  
75V?K  
>9.xFiq<  
public static void log(int sMsg) fscAG\>8  
{ 5/O;&[lYy  
System.err.println(sMsg); $3Ct@}=n  
} I(dMiL  
} bNG;`VZ%  
^{T3lQvt  
6h|@Bz/A  
/* r%g?.4o*b  
**TestMethod.java \&p MF  
*/ oiq7I@Y`x  
package NetFox; N'nqVYTU  
-/.Xf<y58  
ji[O?  
public class TestMethod { _/_1:ivY8  
;$y(Tvd;  
ec4jiE  
public TestMethod() 7lvUIc?krW  
{ ///xx/weblogic60b2_win.exe l ^*GqP5  
try{ /IS j0"/$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?N,'1I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 38
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SiteFileFetch fileFetch = new SiteFileFetch(bean); E Cx_ [|3{  
fileFetch.start(); <
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} K`nI$l7hg  
catch(Exception e){e.printStackTrace ();} j3bTa|UdT  
[9WtoA,k
x  
_|S>,D'  
} _G!lQ)
1  
h7-!q@  
.oq!Ys4KA  
public static void main(String[] args) bqXCe\#  
{ AFWcTz6#d  
new TestMethod(); l
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} Q)c$^YsI  
} e'oM%G[  
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