http断点续传简单实现（java)

/* 87+.pM|t%  
**SiteFileFetch.java "-28[a3q  
*/ g(KK9Unu  
package NetFox; 5"$e=y/  
import java.io.*; ypgliq(  
import java.net.*; IN<:P  
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public class SiteFileFetch extends Thread { {qY3L8b  
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SiteInfoBean siteInfoBean = null; //文件信息Bean H]VsOr  
long[] nStartPos; //开始位置 V/@[%w=  
long[] nEndPos; //结束位置 >).@Nb;e  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $^] 9  
long nFileLength; //文件长度 VtD@&N  
boolean bFirst = true; //是否第一次取文件 t
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boolean bStop = false; //停止标志 K<RmaXZ  
File tmpFile; //文件下载的临时信息 0BT;"B1  
DataOutputStream output; //输出到文件的输出流 )o86lH"z  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -hQ96S8  
public SiteFileFetch(SiteInfoBean bean) throws IOException &qNP?>C!=  
{ G~JCgi  
siteInfoBean = bean; _'H2>V_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jkZ_c!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); PG\\V$}A(  
if(tmpFile.exists ()) 'uws  
{ !}z%#$  
bFirst = false; )lQN)!.)  
read_nPos(); 0T7M_G'5Q  
} ~o}moE/ ;O  
else 0@o;|N"i  
{ ])+Sc"g4k  
nStartPos = new long[bean.getNSplitter()]; H<v c\r  
nEndPos = new long[bean.getNSplitter()]; |*lH9lWJ  
} A$%@fO.b  
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} (r.$%[,.<  
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public void run() We[<BJo4  
{ |3s.;wK  
//获得文件长度 *K]>}  
//分割文件 eUX@9eML  
//实例FileSplitterFetch C}x4#bNK  
//启动FileSplitterFetch线程 Kh>?!`lL  
//等待子线程返回 0*37D5jH  
try{ 3FGbQ_  
if(bFirst) #k"1wSx16  
{ }".\ 4B$n  
nFileLength = getFileSize(); tpN]evp|  
if(nFileLength == -1) B)(p9]q  
{ nwZ[Ygl|  
System.err.println("File Length is not known!"); c2tEz&=G  
} ~r(g|?}P  
else if(nFileLength == -2)
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{ V`WI"HO+  
System.err.println("File is not access!"); gn-=##fT:i  
} (2\li{$e  
else `=_7I?  
{ 0L3Bo3:k  
for(int i=0;i<nStartPos.length;i++) gubb .EY  
{ =YS!soO  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} s98: *o3  
for(int i=0;i<nEndPos.length-1;i++) D<+ bzC  
{ E#yCcC!wMY  
nEndPos = nStartPos[i+1]; [X0k{FR  
} uYG #c(lc  
nEndPos[nEndPos.length-1] = nFileLength; )_Z]=5Ds  
} BsoFQw4$9  
} Y2RxD\!Z  
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m]+X}|  
//启动子线程 9'L1KQ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^N*pIVLC  
for(int i=0;i<nStartPos.length;i++) |HKHN?)  
{ 8cYuzt]..  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @c.11nfn`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $bF`PGR_  
nStartPos,nEndPos,i); YHwVj?6W  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I v 80,hW  
fileSplitterFetch.start(); T>
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} )W_ Y3M,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,*9#c
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =RCfibT!C  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;/6:lL  
nEndPos = " + nFileLength); {,n
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// fileSplitterFetch[nPos.length-1].start(); |THkS@Br  
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/NPl2\o.  
//等待子线程结束 >tE
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//int count = 0; $g}/T_26  
//是否结束while循环 LbtlcpF*~5  
boolean breakWhile = false; 1Ud t9$~T  
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while(!bStop) >X@.f1/5X  
{ zWKrt.Dg  
write_nPos(); fzPgX  
Utility.sleep(500); K284R=j -&  
breakWhile = true; H4K(SGx  
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for(int i=0;i<nStartPos.length;i++) Q!BkS=H30K  
{ -7C=- \]  
if(!fileSplitterFetch.bDownOver) (AyRs7Dkn  
{ hs -}:^S`  
breakWhile = false; #U6/@l)  
break; 93zlfLS0  
} DI2S %Nl  
} DcFV^8O&  
if(breakWhile) .q'FSEkMJ  
break; uMq\]
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6 ^6uK  
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//count++; B<|q{D$N/  
//if(count>4) l1`c?Y  
// siteStop(); JY;#]'T\;  
} X~<>K/}u5  
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System.err.println("文件下载结束！"); !Cv<>_N).  
} [8om9 Z3  
catch(Exception e){e.printStackTrace ();} BhhK|U/  
} .[eSKtbc)  
FHnHhB[  
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//获得文件长度 k^vmR
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public long getFileSize() OM.(g%2  
{ ,rvZW}=  
int nFileLength = -1; MZhJ,km)  
try{ *Kp
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URL url = new URL(siteInfoBean.getSSiteURL()); <T=o]M$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sVZ}nq{  
httpConnection.setRequestProperty("User-Agent","NetFox");  # 8-P  
6=[ PJM  
KlSY^(kHR  
int responseCode=httpConnection.getResponseCode(); swe8  
if(responseCode>=400) 'DB({s  
{  ZeDDH  
processErrorCode(responseCode); H]]>sE  
return -2; //-2 represent access is error `(w kqa  
} %CfTqbB  
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String sHeader; OkO@BWL  
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for(int i=1;;i++) ::Ve,-0  
{ n$\6}\k  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); KcMzZ!d7m  
//Utility.log(in.readLine()); Lh5+fk~i~8  
sHeader=httpConnection.getHeaderFieldKey(i); l<+,(E=  
if(sHeader!=null) <P Z\qE*+y  
{ _ZvX"{y~  
if(sHeader.equals("Content-Length")) EWvid4QEi  
{ [+[fD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7C6BZ$(  
break; %%-Tjw o  
} 9"l%tq_  
} 9ixnf=$Jp  
else G#=b6DB  
break; S3[oA&  
} L:];[xa%  
} sjg
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catch(IOException e){e.printStackTrace ();} Q0oDl8
~  
catch(Exception e){e.printStackTrace ();} ZBh@%A  
'XjHB!!hU  
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Utility.log(nFileLength); }Q,C;!'"  
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return nFileLength; ,jdKcWy'  
} bgx5{!A  
_M[[o5{  
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//保存下载信息（文件指针位置） _KlPbyLU  
private void write_nPos() )Z`viT  
{ .~/;v~bL  
try{ }N=zn7W  
output = new DataOutputStream(new FileOutputStream(tmpFile)); I5AjEp  
output.writeInt(nStartPos.length); jq]\oY8y  
for(int i=0;i<nStartPos.length;i++) ]{l O  
{ ;Q%19f3,6  
// output.writeLong(nPos); \}_7^)S;  
output.writeLong(fileSplitterFetch.nStartPos); Ffqn|}gb  
output.writeLong(fileSplitterFetch.nEndPos); vskM;  
} 'Y/V9;`)s  
output.close(); O"w_sw  
} MDXQj5s^  
catch(IOException e){e.printStackTrace ();} ` G/QJH{I  
catch(Exception e){e.printStackTrace ();} NhaeAD $e  
} % w/1Uo24  
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{Eb2<;1o{  
//读取保存的下载信息（文件指针位置） $2Tty 7  
private void read_nPos()
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{ ZJ'H y5?  
try{ \~m%4kzG8J  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); LHGK!zI  
int nCount = input.readInt(); XwqfWd
_  
nStartPos = new long[nCount]; 7qdl,z  
nEndPos = new long[nCount]; "gVH;<&]  
for(int i=0;i<nStartPos.length;i++) QrRCsy70  
{ (inwKRH  
nStartPos = input.readLong(); v6(l#,  
nEndPos = input.readLong(); nT6iS}h  
} "MKsSty  
input.close(); `rFGSq$9  
} bqLYF[#T  
catch(IOException e){e.printStackTrace ();} qQ\hUii  
catch(Exception e){e.printStackTrace ();} }z%/6`7)|  
} TEy.zzt  
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private void processErrorCode(int nErrorCode) H5rNLfw '  
{ +R jD\6bJb  
System.err.println("Error Code : " + nErrorCode); 6O?Sr,  
} UEb'E;  
L ~'N6  
j;c^pLUP  
//停止文件下载 Q14;G<l-  
public void siteStop() I.0Usa"z  
{ q>h+Ke  
bStop = true; Y  .X-8  
for(int i=0;i<nStartPos.length;i++) M>l+[U  
fileSplitterFetch.splitterStop(); jT_Tx\k  
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n!,TBCNX  
} ' =s*DL`0  
} [UrS%]OSR  
//负责部分文件的抓取 \d8=*Zpz7  
**FileSplitterFetch.java oEf^o*5(  
*/ $XzlW=3y  
package NetFox; )Syf5I  
{@`Uf;hPAX  
[1X5r<(W5  
import java.io.*; ]uXsl0'`V  
import java.net.*; Ho*RLVI0U  
Aba%Gh  
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public class FileSplitterFetch extends Thread { ?DTP-#5Ba  
h1d0{  
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String sURL; //File URL JHOBg{Wg  
long nStartPos; //File Snippet Start Position 2:0Y'\nn  
long nEndPos; //File Snippet End Position omU)hFvyS  
int nThreadID; //Thread's ID 6>^k9cJp  
boolean bDownOver = false; //Downing is over Ny<G2!W  
boolean bStop = false; //Stop identical H%jIjf  
FileAccessI fileAccessI = null; //File Access interface 4E94W,1%,Y  
LPgI"6cP  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _A~gqOe  
{ E^ti!4{<  
this.sURL = sURL; \?IwR]@y  
this.nStartPos = nStart; \Xp"I5  
this.nEndPos = nEnd; 8x
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nThreadID = id; <W{0@?y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %HS!^j3C%  
} =C}<0<"iF  
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public void run() tOVm~C,R  
{ 0(6`dr_  
while(nStartPos < nEndPos && !bStop) gx.]4v  
{ 3Q"+ #Ob  
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try{ :cz]8~i\  
URL url = new URL(sURL); c3BL2>c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox");
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String sProperty = "bytes="+nStartPos+"-"; 1Ac1CsK*  
httpConnection.setRequestProperty("RANGE",sProperty); g0$k_  
Utility.log(sProperty); f@g  
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InputStream input = httpConnection.getInputStream(); CR=MjmH  
//logResponseHead(httpConnection); %P6!vx:&^b  
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byte[] b = new byte[1024]; ,_-*/- 7;8  
int nRead; d8I:F9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]jrxrUl  
{ fL:Fn"Nv  
nStartPos += fileAccessI.write(b,0,nRead); BS.6d}G4  
//if(nThreadID == 1) .`RC,R`C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^%^0x'"  
} 9jO+ew  
U$Z}<8  
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Utility.log("Thread " + nThreadID + " is over!"); MPc=cLv  
bDownOver = true; fe/6JV  
//nPos = fileAccessI.write (b,0,nRead); e8v=n@0  
} p$<qT^]&  
catch(Exception e){e.printStackTrace ();} a06q-3zw  
} %tLq&tyeY  
} Jp0.h8i  
jXR+>=_  
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//打印回应的头信息 g{(nt5|^l  
public void logResponseHead(HttpURLConnection con) >4b39/BM  
{ WGK::?  
for(int i=1;;i++) *RM'0[1F4  
{ Uc2#so$9  
String header=con.getHeaderFieldKey(i); Z;s-t\C  
if(header!=null) g&wQ^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); v,B\+q/  
Utility.log(header+" : "+con.getHeaderField(header)); _Y=yR2O  
else mAa]Et.  
break; kMXl {  
} s9>!^MzBK  
} S#dS5OX  
0rUf'S ?K  
* vD<6qf  
public void splitterStop() Hq$|j,&?  
{ 2T9Z{v  
bStop = true; vS#]RW&j  
} :P~Owz  
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} 1doqznO  
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/* f'S"F  
**FileAccess.java N5DS-g
v  
*//文件访问(定位，写) b.&YUg[#  
package NetFox; {'(8<n5
7  
import java.io.*; 8),Y|4  
7(Kc9sJC%%  
d\M !o
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public class FileAccessI implements Serializable{ jK53-tF~I  
;*p}~#2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Q{60^vg  
RandomAccessFile oSavedFile; 7j8_O@_  
long nPos; ;q2T*4NN  
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}p~%GA.=98  
public FileAccessI() throws IOException 5"U7I{\  
{ Sy~1U  
this("",0); K#@FKv|("  
} 4NIfQYC.  
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clNP9
{  
public FileAccessI(String sName,long nPos) throws IOException jC%I]#!n  
{ ! ZEKvW  
oSavedFile = new RandomAccessFile(sName,"rw"); 6s;x@g]  
this.nPos = nPos; ;]!  
oSavedFile.seek(nPos); O/Vue  
} 8z"Yo7no  
sTDBK!9I  
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public synchronized int write(byte[] b,int nStart,int nLen) 5Mr:(|JyV  
{ Y|F);XXIl  
int n = -1; rH,N.H#]  
try{ {YFru6$  
oSavedFile.write(b,nStart,nLen); ||f4f3R'  
n = nLen; 4.TG&IQ nN  
} U' Cp3>  
catch(IOException e) DNPK1e3a{  
{ {$^|^n5j  
e.printStackTrace (); v]v f(]""  
} trLs4o,  
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CfU)+20  
return n; `0D
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} novZ<?7 5;  
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} l}x{.q7Ul  
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/* UWHC]V?  
**SiteInfoBean.java Hg4Ut/0  
*/ @)B_e*6>'  
package NetFox; "<n{/x(  
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~X/T6(n$  
public class SiteInfoBean { [>E0(S]  
`*]r.u0  
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private String sSiteURL; //Site's URL ^:BRbp37i  
private String sFilePath; //Saved File's Path \MU4"sXw  
private String sFileName; //Saved File's Name PA E)3  
private int nSplitter; //Count of Splited Downloading File L<:ya  
dx^3(#B  
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public SiteInfoBean() 4?Io@[7A)  
{//nSplitter的缺省值为5 (&S v$L@  
//default value of nSplitter is 5 I ;_.tG  
this("","","",5); Nn$$yUkMX  
} 08Q:1 '  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)
IH5thL@D  
{ ;(V=disU/  
sSiteURL= sURL; tc[PJH&P  
sFilePath = sPath; k(MQ:9'|  
sFileName = sName; &>-Cz%IV  
this.nSplitter = nSpiltter; aUnm9
ur  
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} =c|Bu^(Ctw  
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public String getSSiteURL() o}T]f(>}  
{ IAfYlS#<yD  
return sSiteURL; .D :v0Zm}m  
} tQ/U'Ap&  
er53?z7zP.  
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public void setSSiteURL(String value) HV}NT~
 
{ Y !`H_Qo  
sSiteURL = value; ]C!u~A\jq  
}  *q^'%'  
!MbRI  
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public String getSFilePath() og>f1NwS[  
{ bH
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return sFilePath; _2|,j\f;L  
} #8PjYB  
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public void setSFilePath(String value) j1BYSfX'  
{ /:S.("Unv  
sFilePath = value; eA!aUu  
} w:qwU\U>x  
.N%$I6w
 
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public String getSFileName() m+o>`1>a  
{ LcF0:h'  
return sFileName; G^+0</Q  
} @FQ@*XD  
-/h$Yb  
kr3ZqMfeI  
public void setSFileName(String value) ^!A{ 4NV  
{ "$WZd  
sFileName = value; G",+jR]  
} D,NjDIG8  
rP*?a~<  
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public int getNSplitter() lY6U$*9c  
{ j*CnnM#n  
return nSplitter; #oHHKl=M  
} UOa{J|k>h  
;N)qNiJY  
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public void setNSplitter(int nCount) er97&5  
{ b7\nCRY  
nSplitter = nCount; n|(Y?`(  
} 7Q^
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} vZ*593C8  
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/* Z rvb %  
**Utility.java P/^:If
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*/ OrzDr  
package NetFox; akaQ6DIdG  
\;Ii(3+v;  
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public class Utility { T'w=v-(J  
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<}|+2f233+  
public Utility() u\6:Txqq  
{ v=|ahsYC  
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} 6}[W%S]8  
gPDc6{/C<  
//线程睡眠 ;0ake%v]  
public static void sleep(int nSecond) 'GAjx{gM  
{ ,KZ_#9[>  
try{ @*F NWT6  
Thread.sleep(nSecond); `?~pk)<C].  
} 9HWtdJ+^C=  
catch(Exception e) L>cTI2NB.  
{ x H\5T!  
e.printStackTrace (); !)ee{CwNc  
} =T9QmEBm  
} $LKn
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i/~A7\:8%  
//日志 92XzbbLp  
public static void log(String sMsg) uQrD}%GI  
{ P
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System.err.println(sMsg); %|4Nmf$:Og  
} ?FD^S~bz-  
{]`O$S  
K o,O!T.  
public static void log(int sMsg) X5=Dc+  
{ ]
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System.err.println(sMsg); k|1/gd5  
} 1H%LUA  
} 7?e
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q0$}MB6  
Xn4U!<RT"  
/* }VdohX-  
**TestMethod.java jeC3}BL}  
*/ DjtUX>e  
package NetFox; 1Qv5m^>vj  
]r{y+g|  
Q R;Xj3]v  
public class TestMethod {   "Qm  
e5C560  
}>>BKn   
public TestMethod() V{ECDgP  
{ ///xx/weblogic60b2_win.exe d XrLeoK  
try{ "\Z.YZUa\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *RivZ c9;P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (;V6L{Rf>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); BA53
 
fileFetch.start(); Ac|IBXGa=  
} &")ON[|b  
catch(Exception e){e.printStackTrace ();} 2{% U\^-  
dk# LAm0<  
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} 
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z\{y[3-  
*#w+*ywVZH  
public static void main(String[] args) i_Ab0vye  
{ w>J|416  
new TestMethod(); GeD^-.^  
} b+9M? k"  
} ]:8:|*w  
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