http断点续传简单实现（java)

/* E':y3T@."  
**SiteFileFetch.java 0'c<EJ  
*/ ,R3D  
package NetFox; ,t(y~Z wJ  
import java.io.*; rQ@,Y"  
import java.net.*; |o|0qG@g  
,r:. 3.  
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public class SiteFileFetch extends Thread { `"Tx%>E(U  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \[+ZKj:  
long[] nStartPos; //开始位置 +twJHf_U  
long[] nEndPos; //结束位置 'hg, W]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <b{Le{QJ*  
long nFileLength; //文件长度  }m\  
boolean bFirst = true; //是否第一次取文件 a:H}c9$%  
boolean bStop = false; //停止标志 JY_+p9KfyQ  
File tmpFile; //文件下载的临时信息 T[~ak"M  
DataOutputStream output; //输出到文件的输出流 ]
.
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +.b~2K1  
public SiteFileFetch(SiteInfoBean bean) throws IOException gj$gqO`B  
{ PHT;%;m=  
siteInfoBean = bean; !@p@u;djJ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [ wr0TbtV  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Xp4pN{
he  
if(tmpFile.exists ()) rqT@i(i  
{ #eR*|W7o  
bFirst = false; _lu.@IX-  
read_nPos(); 8&3+=<U  
} CIYTs,u#  
else kplyZ  
{ +8mfq\Y1  
nStartPos = new long[bean.getNSplitter()]; )u(`s`zd  
nEndPos = new long[bean.getNSplitter()]; HVh+Zk  
} mY |$=n5X  
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} E.}T.
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public void run() "72 _Sw  
{ ^#vWdOlt  
//获得文件长度 C(xdiQJh  
//分割文件 Qm^N}>e  
//实例FileSplitterFetch ERCW5b[RT  
//启动FileSplitterFetch线程 lHT?  
//等待子线程返回 li$(oA2  
try{ G'#a&6  
if(bFirst) CQ"5bnR  
{ drNfFx2  
nFileLength = getFileSize(); [gqV}Y"Md  
if(nFileLength == -1) oju4.1  
{ P0 hC4Sxf  
System.err.println("File Length is not known!"); GyRU/0'BME  
} ZMy,<wk  
else if(nFileLength == -2) 7o'kdYJzo  
{ G0xk @SE  
System.err.println("File is not access!"); FgKDk!ci  
} p/4GO
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else u2@:[:Ao  
{ 1`X{$mxw  
for(int i=0;i<nStartPos.length;i++) OqHD=D[  
{ {6 C!^ 5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _LCK|H%v'  
} BQ2DQ7
q  
for(int i=0;i<nEndPos.length-1;i++) w)5eD+n\-  
{ &,3.V+Sz  
nEndPos = nStartPos[i+1]; |r%6;8A]i  
} zxT&K|  
nEndPos[nEndPos.length-1] = nFileLength; u\Tq5PYXt  
} SHIK=&\~-  
} e#<%`\qH  
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./rNq!*a  
//启动子线程 :>\i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; m';:):  
for(int i=0;i<nStartPos.length;i++) @'7'3+ c  
{ T%VC$u4F  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C8e{9CF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), CRw.UC\  
nStartPos,nEndPos,i); 6zaO$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TO-[6Pq#  
fileSplitterFetch.start(); z|<6y~5,  
} wS hsu_(i  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); L:}hZf{p*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (w6024~  
nEndPos = " + nFileLength); 6Y`eYp5A  
// fileSplitterFetch[nPos.length-1].start(); mXAX%M U  
;Ze}i/l  
OLXG0@  
//等待子线程结束 ,1a6u3f,  
//int count = 0; K\,)9:`t  
//是否结束while循环 dE%rQE7'  
boolean breakWhile = false; ovvR{MTc  
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while(!bStop) zr-HL:js  
{ 6H53FMqr  
write_nPos(); }[l
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Utility.sleep(500); {M)Y6\v  
breakWhile = true; a[1^)=/DM  
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for(int i=0;i<nStartPos.length;i++) >h(n8wTP  
{ N! 
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if(!fileSplitterFetch.bDownOver) C-V,3}=*2  
{ 7b_t%G"  
breakWhile = false;
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break; @aAB#,  
} bzF>Efza  
} X6)-1.T&  
if(breakWhile) ;%0$3a  
break; x&@. [FJhO  
zgI!S6q  
1I{vBeMj  
//count++; |Rd?s0u  
//if(count>4) _)"-zbh}{  
// siteStop(); SDwTGQ/0  
} yT.h[yv"w  
-Wd2FD^x  
;}@.E@s%'  
System.err.println("文件下载结束！"); {^a"T'+  
} FAX|.!US*p  
catch(Exception e){e.printStackTrace ();} sf<S#;aYqn  
} MX2]Q  
lA<n}N)j  
;:4&nJ*qG  
//获得文件长度 P<ElH3J`  
public long getFileSize() ]bLI!2Kr  
{ u!hY bCB  
int nFileLength = -1; 1hp`.!3]H  
try{ ?#YheML?  
URL url = new URL(siteInfoBean.getSSiteURL()); :PE{2*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  Tvqq#;I  
httpConnection.setRequestProperty("User-Agent","NetFox"); WYSqnmi  
BiT #bg  
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int responseCode=httpConnection.getResponseCode(); 
Fku~'30  
if(responseCode>=400) eyUguA<lK\  
{ N?hQ53#3  
processErrorCode(responseCode); -d1 YG[1|  
return -2; //-2 represent access is error zl^ %x1G  
} dWqKt0uh!  
?<)4
_  
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String sHeader; #I8)|p?P  
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for(int i=1;;i++)
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{ c<bV3,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U*(/eEtd-  
//Utility.log(in.readLine()); uatY:GSR  
sHeader=httpConnection.getHeaderFieldKey(i); v3PtiKS  
if(sHeader!=null) BbsgZ4  
{ ;-sZaU;  
if(sHeader.equals("Content-Length")) FjR/_GPo6  
{ MdXOH$ps  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !IF]P#  
break; C@d*t?  
} DcYL8u  
} .8e]-^Z  
else ])OrSsV}  
break; P1C{G'cR  
} /S2lA>  
} (KxI*  
catch(IOException e){e.printStackTrace ();} C# zYZ JZ  
catch(Exception e){e.printStackTrace ();} 1Xzgm0OS;  
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Utility.log(nFileLength); -UY5T@as  
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return nFileLength; V6Z~#=EQ  
} $~7uDq  
^/]w}C#:d  
M^IEu}  
//保存下载信息（文件指针位置） }uP`=T!"8  
private void write_nPos() $ix:S$  
{
YYNh| 2  
try{ q8A;%.ZLG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); f euATL]  
output.writeInt(nStartPos.length); }aO6%  
for(int i=0;i<nStartPos.length;i++) 8u8-:c%{  
{ O|K-UTWH%  
// output.writeLong(nPos); MrjgV+P}[  
output.writeLong(fileSplitterFetch.nStartPos); &3gC&b^i  
output.writeLong(fileSplitterFetch.nEndPos); CWT#1L=  
} _D+pJ{@W  
output.close(); gy5^JL  
} )j,Y(V$P  
catch(IOException e){e.printStackTrace ();} Fi+8|/5  
catch(Exception e){e.printStackTrace ();} ^AhV1rBB  
} ~:FF"T>  
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//读取保存的下载信息（文件指针位置） C)UL{n  
private void read_nPos() OSoIH`tA  
{ LV2#w_^I  
try{ >0F)^W?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ncGt-l<9  
int nCount = input.readInt(); R7\T.;8+  
nStartPos = new long[nCount]; Cv[_N%3[  
nEndPos = new long[nCount]; hgg8r#4q  
for(int i=0;i<nStartPos.length;i++) OQ(w]G0LP  
{ B]2m(0Y>>v  
nStartPos = input.readLong(); H 48YX(HI  
nEndPos = input.readLong(); i~3\jD=<  
} ^4/   
input.close(); !$u:_8  
} )J^5?A  
catch(IOException e){e.printStackTrace ();} ,V^2Oa  
catch(Exception e){e.printStackTrace ();} 1X5M
knA  
} :$6mS[@|  
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private void processErrorCode(int nErrorCode) h;Hg/jv  
{ B4@1WZn<8  
System.err.println("Error Code : " + nErrorCode); e&@;hDmIX  
} L"KKW c  
knfEbH  
<-6f}wN  
//停止文件下载 %$Dn);6=  
public void siteStop() nsL"'iQ  
{ b>h L*9  
bStop = true; *{:Zdg'~E
 
for(int i=0;i<nStartPos.length;i++) E3hXs6P  
fileSplitterFetch.splitterStop(); ~P7zg!p/q  
_V`F_C\\#  
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} *iX PG9XZ  
} 4A0v>G`E*#  
//负责部分文件的抓取 o9rZ&Q<  
**FileSplitterFetch.java sU(<L0  
*/ a B$x(8pP@  
package NetFox; DD5cUlOSu  
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import java.io.*; iE0x7x P_  
import java.net.*; 'yo-`nNFD  
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public class FileSplitterFetch extends Thread { |.z4
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{uDH-b(R  
qTrM*/m:]L  
String sURL; //File URL 8-_atL  
long nStartPos; //File Snippet Start Position .],:pL9d  
long nEndPos; //File Snippet End Position *Sg6VGP  
int nThreadID; //Thread's ID ){LU>MW{&  
boolean bDownOver = false; //Downing is over HvR5-?qQ  
boolean bStop = false; //Stop identical XuoyB{U  
FileAccessI fileAccessI = null; //File Access interface (gRTSd T?  
mEmgr(W  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h,\5C/  
{ aX,6y1  
this.sURL = sURL; KV8O
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this.nStartPos = nStart; 5O(U1 *  
this.nEndPos = nEnd; %I=/ y  
nThreadID = id; wRdN(`;v  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 EK.n $  
} EfB.K}b^  
\9fJ)*-  
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public void run() j[Jwa*GQP  
{ :HM~!7e  
while(nStartPos < nEndPos && !bStop) .6!cHL3ln  
{ bt*  
2]y Hxo/6  
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try{ ;qO3m-(d  
URL url = new URL(sURL); Kv)Kn8df  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f?r{Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); AJ>$`=  
String sProperty = "bytes="+nStartPos+"-"; ]VR79l  
httpConnection.setRequestProperty("RANGE",sProperty); Wf3{z D~  
Utility.log(sProperty); #_Zkke~{  
QFK'r\3pU  
p//mVH%  
InputStream input = httpConnection.getInputStream(); Mtl`A'KQ/K  
//logResponseHead(httpConnection); AC\y|X8-  
o5['5?i}/  
;eJ|)*  
byte[] b = new byte[1024]; :%g
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int nRead; $ y(Qdb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) K5RgWP  
{ ]s0GAp"
 
nStartPos += fileAccessI.write(b,0,nRead); D9  Mst6  
//if(nThreadID == 1) ~W-l|-eogz  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f%3MDI  
} /2''EF';  
1,Es'  
'C=(?H)M  
Utility.log("Thread " + nThreadID + " is over!"); L=<$^m  
bDownOver = true; U'^ G-@  
//nPos = fileAccessI.write (b,0,nRead); l,9rd[  
} Ng1bjq}E2  
catch(Exception e){e.printStackTrace ();} TS`m&N{i")  
}  @EURp  
} *kTj,&x[  
g*Pn_Yo[.  
EL%Pv1  
//打印回应的头信息 j<QK1d17  
public void logResponseHead(HttpURLConnection con) t%%zuqF`  
{ 6-~ZOMlV  
for(int i=1;;i++) G)?j(El  
{ <00nu'Ex1v  
String header=con.getHeaderFieldKey(i); \x<,Ma=D  
if(header!=null) QL @SE@"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &lID6{79Z  
Utility.log(header+" : "+con.getHeaderField(header)); g##<d(e!}  
else nXk9 IG(  
break; ~]24">VZf  
} \irKM8]LJ  
} gil:SUW1r  
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/3.;sS]B  
public void splitterStop() He$v'87]  
{ )Y&B63]B  
bStop = true; RD0*]4>]  
} KMG}VG   
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} belBdxa{"  
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/* ~Y{]yBGoF  
**FileAccess.java L
r20xm  
*//文件访问(定位，写) 8QMMKOui\  
package NetFox; <Qr*!-Kc6  
import java.io.*; elR1NhB|p  
-]-0]*oAp  
@=}NMoNH  
public class FileAccessI implements Serializable{ fT{jD_Q+3  
 ^Y!$WP  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 H]*B5Jv~  
RandomAccessFile oSavedFile; oGyo
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long nPos; }8ESp3~e_  
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mKE'l'9A_  
public FileAccessI() throws IOException
oKr= ]p  
{ EiP N44(  
this("",0); ]T(qk  
} oCLM'\  
<(~Wg{  
vXZP>  
public FileAccessI(String sName,long nPos) throws IOException ?%%vQ?  
{ 3g:P>(  
oSavedFile = new RandomAccessFile(sName,"rw"); SmRFxqtN  
this.nPos = nPos; unRFcjEa  
oSavedFile.seek(nPos); J7`;l6+Gb  
} 4uh~@Lv  
<IBUl}|\  
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public synchronized int write(byte[] b,int nStart,int nLen) UV</Nx)3  
{ APJFy@l}  
int n = -1; t'yh&44_  
try{ 7*%}=.  
oSavedFile.write(b,nStart,nLen); _{ 2`sL)  
n = nLen; kyZZ0  
} |MN2v[y  
catch(IOException e) qG2P?DR  
{  z).&0K  
e.printStackTrace (); fh66Gn,  
} 4#t=%}  
AFeFH.G6Jr  
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return n; D(&Zq7]n  
} t8;nP[`  
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} .Iz JJp  
(LMT'  
4N1)+W8k*  
/*  ;5  
**SiteInfoBean.java :T>OJ"p  
*/ i7
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package NetFox;
n<@C'\j@  
#Uep|A  
1(_[awBx  
public class SiteInfoBean { Su[(IMw  
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@7;}6,)  
private String sSiteURL; //Site's URL Q'hs,t1<  
private String sFilePath; //Saved File's Path &os:h] C  
private String sFileName; //Saved File's Name 5|`./+Ghk  
private int nSplitter; //Count of Splited Downloading File pV!WZUfg  
2|(lKFkQ  
"\]]?&  
public SiteInfoBean() kn
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{//nSplitter的缺省值为5 |oePB<N  
//default value of nSplitter is 5 RE-y5.kE^  
this("","","",5); K|Xe)  
} -s7!:MB%g  

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#;+SAoN  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !w0=&/Y{R  
{ U7e2NES  
sSiteURL= sURL; 'Q=(1a11  
sFilePath = sPath; b/\l\\$-  
sFileName = sName; 3<[q>7X  
this.nSplitter = nSpiltter; }AiF 7N0  
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/%F,
  
} c+O:n:L  
I]pz3!On4,  
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public String getSSiteURL() fQ-IM/z  
{ *+00  
return sSiteURL; oMYZ^b^  
} ixoN#'y<"  
7{k?"NF  
SL\15`[{  
public void setSSiteURL(String value) fP8bWZ{  
{ C*11?B[  
sSiteURL = value; '$z@40u  
} i[z#5;x+<  
U'Y,T$Q  
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public String getSFilePath() (h[. Ie  
{ cK\?wZ| Y  
return sFilePath; e5"5 U7  
} H|MAbx 7  
[A] +Azc  
t1$pl6&,  
public void setSFilePath(String value) NSR][h_  
{ jfam/LL{V  
sFilePath = value; Adfnd  
} r;>.*60AT  
hM=X# ;  
ER}5`*X{  
public String getSFileName() %WX^']p  
{ Id>I.e4  
return sFileName; ; 0M"T[c  
} >66 `hZ  
znIS2{p/`  
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public void setSFileName(String value) 5)0'$Xxqa0  
{ 3a}c'$F>_'  
sFileName = value; !\OX}kHX5  
} *_HF%JYMZ  
# $'H?lO  
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public int getNSplitter() /#q6.du  
{ FJ{&R Ld  
return nSplitter; hx4c`fOs  
} X+N8r^&  
k@gQY_  
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public void setNSplitter(int nCount) D^U?!S&4~  
{ U]9k,#  
nSplitter = nCount; WZP1g kX&M  
} b?,=|H  
} KYl!Iw67d  
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Ht]O:io`  
/* 5v=e(Ph+  
**Utility.java [F{P0({%?  
*/ e nw*[D !  
package NetFox; g+(Y)9h&  
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F%O+w;J4  
public class Utility { <,U$Y>  
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public Utility() f9)0OHa  
{ a(G}<  
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: JS
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} kE[R9RS!
  
,pVe@d'  
//线程睡眠 $H&:R&Us  
public static void sleep(int nSecond) A!}Ps"Z  
{ i|28:FJA  
try{ fP$rOJ)P  
Thread.sleep(nSecond); "g!ek3w(  
} }'n]C|gZ  
catch(Exception e) FC]n?1?<(  
{ 8==_43  
e.printStackTrace (); F6>oGmLy  
} 0Fsa&<{6?  
} 9o3?  
k-)Ls~#+  
//日志 2h)Qz+|7  
public static void log(String sMsg) Y_~otoSoY  
{ (Ap?ixrR_  
System.err.println(sMsg); )#`&[
9d-  
} bU/YU0ZIT  
'T;;-M3*  
h R6Pj"@0  
public static void log(int sMsg) e_cK#9+  
{ BKgCuz:y  
System.err.println(sMsg); D6C h6i5$  
} I8YCXh  
} .nEiYS|T  
k)W&ZY  
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/* POX{;[SV  
**TestMethod.java 4Tb"+Y
}  
*/ wt
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package NetFox; >5D;uTy u  
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GR_caP  
public class TestMethod { n9-WZsc1  
@Y}G,i  
$R:Q R?   
public TestMethod() u1\r:q  
{ ///xx/weblogic60b2_win.exe H5o=nWQ6e  
try{ QV4FA&f&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4=N(@mS  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Yb1Q6[!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a>Zp?*9  
fileFetch.start(); sk AF6n  
}
{i}E)Np  
catch(Exception e){e.printStackTrace ();} k+Z2)j"  
!/=.~B  
g}L>k}I?!W  
} ntW1 )H'o  
S,Tc\}  
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public static void main(String[] args) Ch:EL-L  
{ MV07RjeS  
new TestMethod(); G&"O)$h  
} t+{vbS0  
} '|<S`,'#hg  
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