http断点续传简单实现（java)

/* 6^Q/D7U;s  
**SiteFileFetch.java 1Z$` }a  
*/ jG E=7  
package NetFox; {\P`-'C  
import java.io.*; %x]8^vze  
import java.net.*; h{5K9$9=  
h,!#YG@>  
f6*6*=  
public class SiteFileFetch extends Thread { HtN!Hgpwg  
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SiteInfoBean siteInfoBean = null; //文件信息Bean CI}zu;4|  
long[] nStartPos; //开始位置 4H]~]?F&  
long[] nEndPos; //结束位置 lG>,&(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 bzC|aUGM  
long nFileLength; //文件长度 'LyEdlC]  
boolean bFirst = true; //是否第一次取文件 tx9;8K3  
boolean bStop = false; //停止标志 X9S`#N  
File tmpFile; //文件下载的临时信息 2d:5~fEJp  
DataOutputStream output; //输出到文件的输出流 cU[^[;4J<  
X%sMna)  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 6!;eJYj,  
public SiteFileFetch(SiteInfoBean bean) throws IOException *URBx"5XZ  
{ `p'(:W3a  
siteInfoBean = bean; tW8&:L,m  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lR8Lfa*/7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jI;iTKjB(  
if(tmpFile.exists ()) Z+%w|Sx  
{ dln1JZ!  
bFirst = false; h8)m2KrZ!.  
read_nPos(); GI ;  
} ALO0yc  
else })#SjFq<V  
{ iL6Yk @  
nStartPos = new long[bean.getNSplitter()]; ,P.yl~'Al  
nEndPos = new long[bean.getNSplitter()]; $-Yq?
:  
} q-lejVS(g  
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} 6]D%|R,Q#}  
h
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public void run() F^/b!)
4X  
{ f7y3BWOi]  
//获得文件长度  L#>^R   
//分割文件 brpsZU  
//实例FileSplitterFetch ;&2f{  
//启动FileSplitterFetch线程 &$V&gAN  
//等待子线程返回 ;J&p17~T9  
try{ #=81`u  
if(bFirst) EG&97lb  
{ )/{zTg8$?/  
nFileLength = getFileSize(); =U- w!uW  
if(nFileLength == -1) zcrM3`Zh  
{ #JD:i%  
System.err.println("File Length is not known!"); oj'a%mx  
} =mQdM]A)2  
else if(nFileLength == -2) )%6h9xyXt  
{ ~#SLb=K   
System.err.println("File is not access!"); 7/>#yR  
} GX\6J]x=^2  
else 8rEUZk  
{ Mcfqo0T-  
for(int i=0;i<nStartPos.length;i++) !C3ozZ<  
{ W-8U~*/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0hB9D{`,{  
} +WTO_J7  
for(int i=0;i<nEndPos.length-1;i++)  qH9bo-6  
{ )a=58r07  
nEndPos = nStartPos[i+1]; qZwqnH  
} t"Tv(W?_  
nEndPos[nEndPos.length-1] = nFileLength; t8:QK9|1  
} m~;}8ObQE  
} '&+5L.  
"WfVZBWG$  
5%#V>|@e#  
//启动子线程 nPRv.h  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; xJ(}?0h-X  
for(int i=0;i<nStartPos.length;i++) gbvMS*KQz  
{ rFLm!J]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wnr<# =,I'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), DN0`vl{*  
nStartPos,nEndPos,i); \|f3\4;!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,l )7]p*X  
fileSplitterFetch.start(); CEXD0+\q  
} ar[I| Q_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Tfow_t}\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Pz77\DpFi  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~\]lMsk+  
nEndPos = " + nFileLength); Ss$/Bh>hN  
// fileSplitterFetch[nPos.length-1].start(); M7PGs-l  
D~T;z pS  
ygo4.  
//等待子线程结束 A}l+BIt  
//int count = 0; ui .riD[,O  
//是否结束while循环 Q| _e=  
boolean breakWhile = false; ,u@V
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while(!bStop) AbA_s I<;  
{
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write_nPos(); g)`;m%DG6  
Utility.sleep(500); T?e(m  
breakWhile = true; 2qgm(jo *y  
y{k65dk-  
{^V9?^?d (  
for(int i=0;i<nStartPos.length;i++) VNT*@^O_=  
{ vAt]N)R  
if(!fileSplitterFetch.bDownOver) 'Z}3XVZEN  
{ QJ^'Uyfdn  
breakWhile = false; my+2@ln  
break; f j:q>}V  
} ZFFK
v  
} O =gv2e  
if(breakWhile) ]*v[6 +  
break; o$rA;^2X  
Y=$PsDh!  
DOB#PI[/  
//count++; uN*Ynf(:-  
//if(count>4)
;_iDiLC;  
// siteStop(); ;kfl5  
} 6+LBs
.vl}  
E'iN==p_:  
S9kA69O  
System.err.println("文件下载结束！"); N?j#=b+D  
} lK"m|Z  
catch(Exception e){e.printStackTrace ();} $VNj0i. Pr  
} yR$ld.[uf  
jzb%?8ZJ  
|6o!]~&e$1  
//获得文件长度 L )53o!  
public long getFileSize() (kmrWx= $  
{ !4vepa}Y  
int nFileLength = -1; n]x%xnt  
try{ 8~j1  
URL url = new URL(siteInfoBean.getSSiteURL()); `)TuZP_)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c_Lcsn  
httpConnection.setRequestProperty("User-Agent","NetFox"); !e?2 x@J  
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int responseCode=httpConnection.getResponseCode(); 
pZ)N,O3  
if(responseCode>=400) Rc2JgV  
{ (TTS-(  
processErrorCode(responseCode); iPCDxDLN3V  
return -2; //-2 represent access is error K:L_y1!T  
} 5MHcgzyp  
#D
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String sHeader; KbGz3O'u  
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t->I# t7  
for(int i=1;;i++) :ZsAWe{%,J  
{ sL4j@Lt  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); xRbtiFk9H  
//Utility.log(in.readLine()); *&doI%q  
sHeader=httpConnection.getHeaderFieldKey(i); rr^?9M*{V  
if(sHeader!=null) _~.S~;o!b  
{ ]Ei*I}  
if(sHeader.equals("Content-Length")) z2U^z
*n{  
{ MRN=-|fV^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); :
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c  
break; .r~M7 I  
} k@|Go)~  
} ESmWK;7b  
else KXT9Wt=  
break; -LU%z'  
} C17$qdV/  
} 4vJg"*?  
catch(IOException e){e.printStackTrace ();} C+%6N@  
catch(Exception e){e.printStackTrace ();} PrhGp _5  
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Utility.log(nFileLength); LhC
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return nFileLength; E RjMe'q4  
} k"F\4M  
2#Du5d  
NC
ivh&HR  
//保存下载信息（文件指针位置） dZ|x `bIgs  
private void write_nPos() $&X-ay o  
{ YB]{gm2  
try{ S+bpWA  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8k )i-&R  
output.writeInt(nStartPos.length); +'9E4Lpx  
for(int i=0;i<nStartPos.length;i++) agd^ga3  
{ i\dd  
// output.writeLong(nPos); ']U<R=5T$  
output.writeLong(fileSplitterFetch.nStartPos); yrG=2{I  
output.writeLong(fileSplitterFetch.nEndPos); S*V!t=  
} q,T4- E  
output.close(); 6PT"9vR`)  
} I~Q G  
catch(IOException e){e.printStackTrace ();} <.=-9O6  
catch(Exception e){e.printStackTrace ();}   bKt4  
}
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3
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//读取保存的下载信息（文件指针位置） Ya;y@44  
private void read_nPos() IG90mpLX  
{ 9`td_qh  
try{ R!rj:f!>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~EM(*k._  
int nCount = input.readInt(); &AnWMFo  
nStartPos = new long[nCount]; p^)w$UL}}  
nEndPos = new long[nCount]; 'fPDODE  
for(int i=0;i<nStartPos.length;i++) u]Z;Q_=  
{ 7O,!67+^~  
nStartPos = input.readLong(); e.WKf,e"X  
nEndPos = input.readLong(); uxlrJ1~M  
} v}TFM  
input.close();  {gb` %
J  
} %5!K?,z%  
catch(IOException e){e.printStackTrace ();} dWP<,Z>  
catch(Exception e){e.printStackTrace ();} R$bDj>8  
} SBg|V  
20/P:;  
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private void processErrorCode(int nErrorCode) U+,RP$r@  
{ ,olP}  
System.err.println("Error Code : " + nErrorCode); yof8LWXx  
} -I[KIeF  
NqM=Nu\  
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//停止文件下载 nd }Z[)  
public void siteStop() `L%<3/hF  
{ _R}yZ=di  
bStop = true; Lk.tEuj=82  
for(int i=0;i<nStartPos.length;i++) QzxEkTc;  
fileSplitterFetch.splitterStop(); ?2,{+d |  
&qP0-x)  
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} nP_)PDTFp  
} ART0o7B  
//负责部分文件的抓取 BS3{TGn  
**FileSplitterFetch.java y@rg_Paq  
*/ 6+4SMf3  
package NetFox; <c$rfjM+JU  
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import java.io.*; W3jwc{lj  
import java.net.*; c7D{^$L9v  
1#9
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public class FileSplitterFetch extends Thread { i,wZNX  
G5ShheZd  
u82(`+B  
String sURL; //File URL J,J6bfR/  
long nStartPos; //File Snippet Start Position CA5T3J@vAQ  
long nEndPos; //File Snippet End Position a n0n8l  
int nThreadID; //Thread's ID $HCgawQ  
boolean bDownOver = false; //Downing is over *U-:2u
f  
boolean bStop = false; //Stop identical T+oOlug  
FileAccessI fileAccessI = null; //File Access interface B!U;a=ia  
5A+@xhRf  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1024L;  
{ e*Y<m\*  
this.sURL = sURL; ^!z(IE'  
this.nStartPos = nStart; MT6"b  
this.nEndPos = nEnd; -Jt36|O  
nThreadID = id; Z!3R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8nwps(3  
} r7FJ
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TfHL'u9B  
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public void run() ^SK!?M  
{ *c 9S.  
while(nStartPos < nEndPos && !bStop) /vC!__K9:  
{ }X. Fm'`  
@^/aS;B$>  
^7yaMB!  
try{ Eu<f  
URL url = new URL(sURL); - ,?LS w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $%4<q0-  
httpConnection.setRequestProperty("User-Agent","NetFox"); R{ udV  
String sProperty = "bytes="+nStartPos+"-"; Tv6y+l  
httpConnection.setRequestProperty("RANGE",sProperty); 9bhubx\^/  
Utility.log(sProperty); =~5N/!  
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InputStream input = httpConnection.getInputStream(); tEt
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//logResponseHead(httpConnection); f8ZuG !U  
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byte[] b = new byte[1024]; w@Asz9Lq%  
int nRead; Z}{]/=h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Xppv  
{ Uf MQ?(,  
nStartPos += fileAccessI.write(b,0,nRead); qoZ)"M  
//if(nThreadID == 1) ,.h@tN<C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EwmNgmYq  
} I9m9`4BK  
}9glr]=  
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Utility.log("Thread " + nThreadID + " is over!"); hA;Ai:8  
bDownOver = true; c,O;B_}M]  
//nPos = fileAccessI.write (b,0,nRead); +TX
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} pjl>ZoOM  
catch(Exception e){e.printStackTrace ();} e7bMK<:r  
} uUV"86B_  
} , &
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#  
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9Ofls9]U  
//打印回应的头信息 aqWlX0+  
public void logResponseHead(HttpURLConnection con) A3*(c3
  
{ NCY2^  
for(int i=1;;i++) hn\d{HP  
{ h-RhmQA=Iz  
String header=con.getHeaderFieldKey(i); '$eJATtC  
if(header!=null) {>
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); }!?RB v'W  
Utility.log(header+" : "+con.getHeaderField(header)); c{ +bY.J  
else 8vtembna4  
break; ,LP^v'[V7  
} .<Jv=  
} y?P`vHf  
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public void splitterStop() qj `C6_?  
{ |
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bStop = true; $rTb'8  
} 8Lgm50bs  
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} Pf<yLT]  
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/* Jgg<u#  
**FileAccess.java l5~O}`gfh  
*//文件访问(定位，写) mlCg&fnDB  
package NetFox; ~MXhp5PI   
import java.io.*; bo(w$& VW  
BFg&@7.X  
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public class FileAccessI implements Serializable{ `34{/}w  
/HS"{@Z"h  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0FY-e~xr  
RandomAccessFile oSavedFile; &%GAPs%  
long nPos; mwyB~,[d+W  
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F3]VSI6^E,  
public FileAccessI() throws IOException Lq1?Y  
{ K#AexA
  
this("",0); &:IcwD&  
} 1r_V$o$  
;ISe@yR;  
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public FileAccessI(String sName,long nPos) throws IOException mF|KjX~s  
{ )7[#Ti  
oSavedFile = new RandomAccessFile(sName,"rw"); u"m(a:jQ  
this.nPos = nPos; ^Il*`&+?P  
oSavedFile.seek(nPos); rf%VSxD9  
} p\F%Nj,  
p!=O>b_f  
7S&$M-k  
public synchronized int write(byte[] b,int nStart,int nLen) 6>)nkD32g  
{ Bf]Bi~w<  
int n = -1; "P54|XIJ\  
try{ ?FjnG_Uz`D  
oSavedFile.write(b,nStart,nLen); Wz"H.hf  
n = nLen; Kop(+]Q&n  
} h3&|yS|  
catch(IOException e) Crg'AB?  
{ ?w'
86^_z  
e.printStackTrace (); xy4+ [u  
} Hk@Gkx_  
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return n; @2a!T03  
} %2\tly!{ %  
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} '6WS<@%}  
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/* M@<9/xPS  
**SiteInfoBean.java f,Dic%$q  
*/ X(X[v]  
package NetFox; ,Kl?-W@  
X-kOp9/.  
qIQRl1Tw;V  
public class SiteInfoBean { h~](9es  
Rz|@BxB>n  
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private String sSiteURL; //Site's URL g#^MO]pY  
private String sFilePath; //Saved File's Path Iz#4!E|<  
private String sFileName; //Saved File's Name .(.
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private int nSplitter; //Count of Splited Downloading File !|i #g$  
3NDddrL9  
^]D1':  
public SiteInfoBean() MuQ)F-GSUu  
{//nSplitter的缺省值为5 _8 |X820  
//default value of nSplitter is 5 i,a"5DR8  
this("","","",5); Iia.`"S  
} ?6&8-zt1?  
F]UH\1  
:S_]!'H  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &JqaIJh
 
{ O>1Cx4s5  
sSiteURL= sURL; J-,ocO  
sFilePath = sPath; i2c|_B  
sFileName = sName; ^Y%_{   
this.nSplitter = nSpiltter; ,!^5w,P:   
|g)>6+?]W  
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}  =gM@[2  
BLO ]78  
?z&%VU"  
public String getSSiteURL() 7[1|(6$  
{ iW>^'W#  
return sSiteURL; %kV7 <:y  
} ,>S7c  
->{-yh]jv  
#0[^jJ3J  
public void setSSiteURL(String value) E'DHO2 Y  
{ |?2fq&2  
sSiteURL = value; 7g(Z
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} (B
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qrw  
*|dK1'Xr  
public String getSFilePath() Pap6JR{7  
{ 2a48(~<_  
return sFilePath; U|%
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} Z9+fTT  
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tLa%8@;'$  
public void setSFilePath(String value) |oXd4  
{ ZDbe]9#Xh  
sFilePath = value; Q]/%Y[%|  
} QR'#]k;>%  
w"s@q$}]8M  
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public String getSFileName()  k-=LD  
{ o?hr>b  
return sFileName; p ZTrh&I]  
} >a<1J(c  
cS9jGD92  
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public void setSFileName(String value) T TN!$?G3  
{ 9"]#.A^Q*  
sFileName = value; ucx02^uA  
} e@W+ehx"  
m)Kg6/MV.  
x'I!f? / &  
public int getNSplitter() </`\3t  
{ ?}4,s7PR  
return nSplitter; ~s'tr&+  
} kt978qfk  
W H/.h$  
7<] EH:9  
public void setNSplitter(int nCount) p|ink):  
{ Pa{  
nSplitter = nCount; V9BW@G@9  
} z m$Sw0#(  
} Wq1 jTIQ  
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o  
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/* 1d<Uwb>  
**Utility.java *b. >  
*/ nJ2x;';lA  
package NetFox; '6 F-%
 
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7*{f*({  
public class Utility { QH9t |l  
l\*9rs:!  
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public Utility() Q7$o&N{  
{ SscB&{f  
/D3{EjUE=  
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} _y^r==  
5o dT\>Sn  
//线程睡眠 2H)4}5H  
public static void sleep(int nSecond) 7PX`kI  
{ , ,{UGe3  
try{ 1 &9|~">{C  
Thread.sleep(nSecond); 6`e7|ilh6  
} Z)#UCoK!c  
catch(Exception e) a,c!#iyl3  
{ 9_?
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e.printStackTrace (); "+ou!YK+  
} ^Fco'nlM  
} 0- )K_JV  
E=p+z"Ui  
//日志 Y"GNJtsL"  
public static void log(String sMsg) %'=*utOxy  
{ zXn-E  
System.err.println(sMsg); PC#^L$cg}  
} #_wq#rF  
:pqUUZ6x&  
,KW Q 6  
public static void log(int sMsg) 9qB0F_xl  
{ q*l4h u%3  
System.err.println(sMsg); S%i^`_=Q  
} ZNX
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} l4oyF|oJTH  
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'p&,'+x  
/*
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**TestMethod.java VI&x1C  
*/ FvxM  
package NetFox; $Iwvecn?I  
_F;v3|`D@<  
'BjTo*TB]Z  
public class TestMethod { ,twx4r^  
esq
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Fz%;_%j  
public TestMethod() /*mF:40M;  
{ ///xx/weblogic60b2_win.exe hw^&{x  
try{ uw}Rr7q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); I+8n;I)]X  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O,Q.-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); hJ}i+[~be  
fileFetch.start(); Rm} ym9  
} z~ cW,  
catch(Exception e){e.printStackTrace ();} N T`S)P*?  
'u7-Qetj  
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} -Uwxmy+  
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#!%  
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public static void main(String[] args) `@/)S^jBau  
{ HeRi67  
new TestMethod(); L=r*bq  
} *VZ|Idp  
} cuhp4!!  
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