http断点续传简单实现（java)

/* Sp 7u_Pq{  
**SiteFileFetch.java fA"<MslKLK  
*/ &}v
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package NetFox; h7bPAW=(  
import java.io.*; 1S+;ZMk  
import java.net.*; >F/XZ
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public class SiteFileFetch extends Thread { 8{R&EijC  
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}TSgAwsbC  
SiteInfoBean siteInfoBean = null; //文件信息Bean MVeFe\r  
long[] nStartPos; //开始位置 F(d:t!  
long[] nEndPos; //结束位置 x|.v{tQa  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 mfZ)^X  
long nFileLength; //文件长度 sB?2*S"X)<  
boolean bFirst = true; //是否第一次取文件 8$\Za,)g  
boolean bStop = false; //停止标志 6tOCZ'f  
File tmpFile; //文件下载的临时信息 ?Fce!J  
DataOutputStream output; //输出到文件的输出流 RTK}mhnV  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） J5O.*&  
public SiteFileFetch(SiteInfoBean bean) throws IOException +C'XS{K,#  
{ t2"@Ps&1|  
siteInfoBean = bean; 2$M,*Dnr  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); g.9L)
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); DH:J  
if(tmpFile.exists ()) d'ZS;l   
{ q<n[.u1@  
bFirst = false; N5m'To]  
read_nPos(); (VR"Mi4  
} G;/Q>V  
else YnSbw3U.I  
{ "\7v  
nStartPos = new long[bean.getNSplitter()]; G@9u:\[l  
nEndPos = new long[bean.getNSplitter()]; IrJ+Jov  
} gdl| ^*tc  
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} ^pj>9%  
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public void run() .hKhrcQp  
{ 'qjX$]H  
//获得文件长度 'fIHUw|  
//分割文件 $`pd|K`  
//实例FileSplitterFetch Kv}k*A% S  
//启动FileSplitterFetch线程 %MN.O-Lc  
//等待子线程返回 e8oKn&  
try{ fe|g3>/|  
if(bFirst) S.: 7k9  
{ 6JSY56v  
nFileLength = getFileSize();
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if(nFileLength == -1) :/6()_>bO  
{ s _~IZ%+<.  
System.err.println("File Length is not known!"); A#(`9  
} q]TqI' o  
else if(nFileLength == -2) bw9 nB{C<  
{ ]BfS270  
System.err.println("File is not access!"); vs+QbI6>-  
} -j&
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else fp{G|.SA  
{ ,
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for(int i=0;i<nStartPos.length;i++) za T_d/?J  
{ 1fY>>*oP  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )|pU.K9qZ  
} JdiP>KXV  
for(int i=0;i<nEndPos.length-1;i++) qz`rL#W]  
{ ZYa\"zp-  
nEndPos = nStartPos[i+1]; qEQAn/&  
} \]8VwsP  
nEndPos[nEndPos.length-1] = nFileLength; }~F~hf>s  
} `a >?UUT4  
} +%XnMl  
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+"8}R~`!  
//启动子线程 }Gr&w-v  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d`Oe_<  
for(int i=0;i<nStartPos.length;i++) ]v\^&7pW  
{ ;'}'5nO=$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &cc9}V)M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), mw4JQ\  
nStartPos,nEndPos,i); )t%h[0{{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RDJ+QOVKg  
fileSplitterFetch.start(); oxfF`L"  
} #dxvz^2V.3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /;l[I=VI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .*Vkua  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B`{mdjMy  
nEndPos = " + nFileLength); ZVL gK}s
 
// fileSplitterFetch[nPos.length-1].start(); >aG=T{  
WL U}  
PO o%^'(  
//等待子线程结束 < bFy(+  
//int count = 0; 2n)gpLIJ  
//是否结束while循环 {q,?<zBzu  
boolean breakWhile = false; Qdu$Os  
|9IC/C!HC  
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while(!bStop) T@P!L  
{ 6{=_718l`  
write_nPos(); vk'rA{x  
Utility.sleep(500); MDHb'<o?y  
breakWhile = true; Y5Z!og  
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for(int i=0;i<nStartPos.length;i++) <6jFKA<  
{ CZ(`|;BC*  
if(!fileSplitterFetch.bDownOver) k!3 cq)  
{ AbfZ++aJ  
breakWhile = false; ORBxD"J&  
break; : @6mFTV  
} 8sg|MWSU  
} ?:igumeYX  
if(breakWhile) E'EcP4eL  
break; gn)R^  
){P^P!s$  
S!hXf|*0[  
//count++; 0%<+J;'o  
//if(count>4) |4mVT&63(  
// siteStop(); c)~h<=)  
} TH4\HY9qa?  
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System.err.println("文件下载结束！"); [T^?Q%h  
} F*` t"7Lm  
catch(Exception e){e.printStackTrace ();} &| !B!eOY  
} z%sy$^v@vD  
|m;L?)
F<  
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//获得文件长度 @AQwr#R"l  
public long getFileSize() %tmp  
{ x[i`S8D  
int nFileLength = -1; PeTA$Yl  
try{ ?S ts
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URL url = new URL(siteInfoBean.getSSiteURL()); H}ZQ?uK;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |V|+lx'sc  
httpConnection.setRequestProperty("User-Agent","NetFox"); ->gZ)?Fqy  
KX4],B5 +  
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int responseCode=httpConnection.getResponseCode(); %8r/oS  
if(responseCode>=400) Ri)uq\E/#  
{ 9Ah[rK*}  
processErrorCode(responseCode); P@0Y./Ds  
return -2; //-2 represent access is error |"]PCb)!  
} x({C(Q'O  
tR)H~l7q  
80;n|nNB  
String sHeader; FTf<c0  
P^)q=A8Z#  
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for(int i=1;;i++) X`JVR"=4  
{ [4Q"#[V&9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :O-1rD  
//Utility.log(in.readLine()); $yu?.b 9H#  
sHeader=httpConnection.getHeaderFieldKey(i); ub K7B |p  
if(sHeader!=null) Eu,`7iQ?(  
{ pqR\>d0  
if(sHeader.equals("Content-Length")) nxo+?:**  
{ )uheV,ZnY  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L{&U V0q!  
break; rwf^,r"r  
} Z?G&.# :  
} w$fJ4+  
else ae+*=,  
break; {38bv.3'  
} o{WyQ&2N  
} F0lOlS   
catch(IOException e){e.printStackTrace ();} F]+~x/!  
catch(Exception e){e.printStackTrace ();} j/!H$0PN  
<AoXEuD  

@n+=vC.xO  
Utility.log(nFileLength);
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y 1\'(1  
 Mps5Vv  
return nFileLength; =^;P#kX  
} 5h{`<W  
+-$Ko fnM  
7h9U{4r: M  
//保存下载信息（文件指针位置） 19UN*g3(  
private void write_nPos() y1f:?L-z  
{ xTz%nx  
try{ W!L+(!&H  
output = new DataOutputStream(new FileOutputStream(tmpFile)); g(4bBa9y  
output.writeInt(nStartPos.length); n/4i|-^  
for(int i=0;i<nStartPos.length;i++) r 2:2,5_  
{ /)3Lnn
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// output.writeLong(nPos); aSutM  
output.writeLong(fileSplitterFetch.nStartPos); 0<p{BL8  
output.writeLong(fileSplitterFetch.nEndPos); R.9V,R5  
} PoSpkJH  
output.close(); a;AzY'R  
} Dt|)=a  
catch(IOException e){e.printStackTrace ();} 8V/L:h#7  
catch(Exception e){e.printStackTrace ();} ~+6Vdxm  
} L=; -x9  
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vX|UgK?2^  
//读取保存的下载信息（文件指针位置） *m+BuGt|  
private void read_nPos() }T_Te?<&  
{ p9eRZVy/  
try{ c3TKl/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); G&f8n  
int nCount = input.readInt(); jM)C4ii.-$  
nStartPos = new long[nCount]; k@mVxnC  
nEndPos = new long[nCount]; 4=8QZf0\  
for(int i=0;i<nStartPos.length;i++) kFLB> j97  
{ GX{XdJD  
nStartPos = input.readLong(); IH*s8tPc  
nEndPos = input.readLong(); @R|'X  
} |I;$M;'r&  
input.close(); GEUg]nw  
} 5*g]qJF  
catch(IOException e){e.printStackTrace ();} xg@NQI@7   
catch(Exception e){e.printStackTrace ();} ),}AI/j;zY  
}
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private void processErrorCode(int nErrorCode) EbNd=Z'J  
{ Dh4 6o|P  
System.err.println("Error Code : " + nErrorCode); XRN+`J  
} iUk-'   
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t<iEj"5  
//停止文件下载 )FN;+"IJ  
public void siteStop() KJn!Ap  
{ e.d #wyeX  
bStop = true; bpAv1udX-W  
for(int i=0;i<nStartPos.length;i++) W!Gdf^Yy<  
fileSplitterFetch.splitterStop(); (.Y/  
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} dq;|?ESP  
} xgu `Q`~  
//负责部分文件的抓取 cf_|nL#9  
**FileSplitterFetch.java #18FA|   
*/ d~J-|yyT  
package NetFox; OWp%v_y]  
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import java.io.*; 2-*V=El  
import java.net.*; J5Z%ImiT^O  
^ <`(lyph  
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public class FileSplitterFetch extends Thread { u^Ku;RQo  
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String sURL; //File URL :(|'S4z  
long nStartPos; //File Snippet Start Position Z6C=T;w  
long nEndPos; //File Snippet End Position @oP_
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int nThreadID; //Thread's ID #65^w=Sp}  
boolean bDownOver = false; //Downing is over {@Yb%{+  
boolean bStop = false; //Stop identical B_`y
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FileAccessI fileAccessI = null; //File Access interface IA zZ1#/3  
+gd2|`#  
NH<gU_s8{9  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qVqRf.-\  
{ u|#>32kV  
this.sURL = sURL; /&#XhrT  
this.nStartPos = nStart; lA(Q@yEW  
this.nEndPos = nEnd; /'2O.d0}.  
nThreadID = id; Wm~` ~P  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Dn9w@KO  
} %.v{N6  
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public void run() N{SQ(%V  
{ &.13dq  
while(nStartPos < nEndPos && !bStop) MB ju![n  
{ j1
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try{ 'nQVj  
URL url = new URL(sURL); 7tM9u5FF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EJ}
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httpConnection.setRequestProperty("User-Agent","NetFox"); g>0XxjP4  
String sProperty = "bytes="+nStartPos+"-"; 1LJuCI=~  
httpConnection.setRequestProperty("RANGE",sProperty); gJiK+&8I  
Utility.log(sProperty); sxKf&p;  
?^mi3VM  
-~[9U,  
InputStream input = httpConnection.getInputStream(); /^
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//logResponseHead(httpConnection); Jf)bHjC_V  
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\6?A!w~6  
byte[] b = new byte[1024]; #o/H~Iv  
int nRead; `O?TUQGR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) k#Of]mXXz  
{ s`j~-P  
nStartPos += fileAccessI.write(b,0,nRead); % }|cb7l  
//if(nThreadID == 1) yH 9!GS#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LTV{{Z+  
} ZoB*0H-  
9//+Bh  
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Utility.log("Thread " + nThreadID + " is over!"); v0Dq@Q1  
bDownOver = true; &c(WE RW?-  
//nPos = fileAccessI.write (b,0,nRead); $mm
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} >SN|?|2U/  
catch(Exception e){e.printStackTrace ();} 9Etz:?)b  
} iI@jZVk  
} 02`$OTKz  
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(6CN/A{qe  
//打印回应的头信息 M2x["  
public void logResponseHead(HttpURLConnection con) q+KzIde|%  
{ +MbIB&fRCB  
for(int i=1;;i++) R3)57OyV  
{ [XRCLi}  
String header=con.getHeaderFieldKey(i); l+V,DCE  
if(header!=null) %<?0apO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); E5el?=,i  
Utility.log(header+" : "+con.getHeaderField(header)); bPD`+:A_  
else 8(.mt/MR
 
break; R+q"_90_  
} Xtz-\v#0o'  
} KTvzOI8  
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public void splitterStop() zf4Ec-)  
{ fPi3sb`}  
bStop = true; qm
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} '
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} *#%9Rp2|  
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/* _LAS~x7,  
**FileAccess.java HkV1sT  
*//文件访问(定位，写) IX: 25CEI2  
package NetFox; w{~+EolK  
import java.io.*; ms($9Lv/  
~^
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public class FileAccessI implements Serializable{ RsU3Gi_Zdz  
kt[:@Nda9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 I/VxZ8
T  
RandomAccessFile oSavedFile; D'Z|}(d&  
long nPos; lnovykR  
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public FileAccessI() throws IOException Am8x74?  
{ [s9O0i" Y  
this("",0); @prG%vb"  
} 4`Q3v4fOF  
6.5T/D*TT  
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public FileAccessI(String sName,long nPos) throws IOException BR'I+lQ  
{ !zPG?q]3  
oSavedFile = new RandomAccessFile(sName,"rw"); "dR|[a<#g  
this.nPos = nPos; $M_x!f'{>  
oSavedFile.seek(nPos); -~eJn'W  
} d!KsNkk  
1Z[/KJ  
|K?#$~  
public synchronized int write(byte[] b,int nStart,int nLen) ;})5:\h  
{ 7'wS\/e4a  
int n = -1; Qr1e@ =B  
try{ ZpUCfS)|&  
oSavedFile.write(b,nStart,nLen); j8|g!>Nv  
n = nLen; w ;daC(:  
} hYQ_45Z*?  
catch(IOException e) *A}cL  
{ g}laG8  
e.printStackTrace (); kc7l
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} mzQ`N}]T:  
b
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return n; |IunpZV  
} %{3 aW>yx  
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}
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/* *. 3N=EO  
**SiteInfoBean.java ,>t69 Ad  
*/ \#68;)+=  
package NetFox; Q]rD}Ckv-  
b 1&i#I?{  
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public class SiteInfoBean { tbnH,*  
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fN"(mW>!  
private String sSiteURL; //Site's URL Bl9jkq ]  
private String sFilePath; //Saved File's Path tBTTCwNT%  
private String sFileName; //Saved File's Name 2_Wg!bq  
private int nSplitter; //Count of Splited Downloading File Qu,8t8  
d:G]1k;z  
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public SiteInfoBean() AxxJk"v'y  
{//nSplitter的缺省值为5 .^$YfTabq  
//default value of nSplitter is 5 JQ:Ri  
this("","","",5); OB~X/  
} ExHKw~y9  
\5Vde%!$Z  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) bCZ gcN  
{ SWp1|.=Sm  
sSiteURL= sURL; zqDR7+]  
sFilePath = sPath; do uc('@  
sFileName = sName; x{NX8lN  
this.nSplitter = nSpiltter; z} '!eCl  
*m%]zj0bo  
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} h7s
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&C>/L;  
public String getSSiteURL() 6<0n *&  
{ ;n\= R 5.  
return sSiteURL; Y!6/[<r$~k  
} s4_/&h  
N_L,]QT?  
 p!Eft/A(  
public void setSSiteURL(String value) vzF5xp.  
{ eMRar<)+#*  
sSiteURL = value; `.y}dh/+0W  
} d--y  
x.1-)\  
$,xnU.n  
public String getSFilePath() bqanFQj  
{ O4<g%.HC6  
return sFilePath; r%DFve:%  
} 50dGBF  
P;PQeXKw  
iR$<$P5  
public void setSFilePath(String value) vpPl$ga5bY  
{ 7u\*_mrv  
sFilePath = value; x\2?y
m@  
} $8l({:*q0  
Wlh~)  
~.%K/=wK@  
public String getSFileName() `V[!@b:  
{ iut`7  
return sFileName; 5>J=YLq  
} $3D'4\X~?  
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]]}tdn_  
public void setSFileName(String value) WWT",gio  
{ PX|=(:(k  
sFileName = value; XWJwJ  
} q P ;A}C  
H"2uxhdLK3  
F_xbwa*=  
public int getNSplitter() #S%Q*k<hw  
{ y]%w)4PS  
return nSplitter; E&yD8=vw  
} crO@?m1  
fAZiC+  
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public void setNSplitter(int nCount) A?G IBjs  
{
b]E|*  
nSplitter = nCount; ?)'~~@NkH  
} 1B*WfP~  
} Qr#1u  
)pw&c_x  
(]/9-\6(#  
/* bbxLBD'  
**Utility.java {%w!@-  
*/
o`khz{SU:  
package NetFox; hVjNZ  
a:~@CUD >I  
)hwV`2>l  
public class Utility { 7j5f ;O^+  
2tayP@$  
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public Utility() @eqeN9e  
{ hzI*{  
4YZS"K'E  
~-a'v!  
} wPbkUVO  
#6Xs.*b5C  
//线程睡眠 {F&-7u0  
public static void sleep(int nSecond) >-E<n8  
{ 7z_;t9Y  
try{ `"vZ);i<  
Thread.sleep(nSecond); pIWI  
} -Xz?s  
catch(Exception e) OT %nrzP  
{ wwKh CmH  
e.printStackTrace (); S{',QO*D6  
} AvR2_  
} _<ut)G^9  
g%[n4  
//日志 t+CWeCp,  
public static void log(String sMsg) T5wjU*=IL  
{ EoX_KG{  
System.err.println(sMsg); +b;hBb]R  
} W{XkVKe1a  
+@X5!S6  
5)1+~B  
public static void log(int sMsg) 7iuQ9q^&  
{ w^K^I_2ge  
System.err.println(sMsg); I PE}gp  
} _eLWQ|6Fx  
} ashcvn~z  
fJjgq)9  
iq?#rb P#I  
/* ~Lfcg*  
**TestMethod.java P[t$\FS  
*/ Kex[ >L10G  
package NetFox; 0ZAj=u@O  
g|PC$p-z+  
0f ER*.F  
public class TestMethod { 8l/[(] &  
1|,Pq9  
gG54:  
public TestMethod() N132sN2  
{ ///xx/weblogic60b2_win.exe ^SEdA=!  
try{ WUAJjds  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); fbZibcQ%k  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); OH<?DcfeL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); T0j2a&Pv  
fileFetch.start(); 3L-^<'~-k;  
} yh;Y,;4  
catch(Exception e){e.printStackTrace ();} :

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} m$>iS@R
 
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^ L:cjY/  
public static void main(String[] args) Hv#q:R8  
{ lQPqcZd  
new TestMethod(); 4C~UcGMv\  
} (k-YI{D3  
} jm>3bd  
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