http断点续传简单实现（java)

/* la!1[VeL  
**SiteFileFetch.java Z^jGT+
2  
*/ ,dGFX]P  
package NetFox; pQ4 %]Api  
import java.io.*; x)%% 5  
import java.net.*; eYnLZ&H5O  
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public class SiteFileFetch extends Thread { KzxW?Ji$S  
mkKRC;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 'Y,+D`&i)  
long[] nStartPos; //开始位置 )<
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long[] nEndPos; //结束位置 PxdJOtI"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ft*G*.0kO  
long nFileLength; //文件长度 rPrEEWS0)  
boolean bFirst = true; //是否第一次取文件 iT)2 ?I6!  
boolean bStop = false; //停止标志 mmh nw(/  
File tmpFile; //文件下载的临时信息 \" 5F;J  
DataOutputStream output; //输出到文件的输出流 !nZI? z;  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） bw<~R2[  
public SiteFileFetch(SiteInfoBean bean) throws IOException GN}9$:  
{ vV\/pu8  
siteInfoBean = bean; UU;Ysj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y2ah zB  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
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if(tmpFile.exists ()) ?eYchVq  
{ #!K~_DL  
bFirst = false; jn5=N[hd  
read_nPos(); +c~O0U1  
} 2J>A;x_?  
else >=]NO'?O
 
{ Hzk1LKsT#  
nStartPos = new long[bean.getNSplitter()]; Wb*T  
nEndPos = new long[bean.getNSplitter()]; r!-L`
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} s%0[
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} Nys'4kx7  
2={K-s20  
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public void run() ;]8p:ME  
{ &Pn%zfmMN  
//获得文件长度 2t Z\{=  
//分割文件 .DM1Knj  
//实例FileSplitterFetch tjc5>T[Es8  
//启动FileSplitterFetch线程 JsoWaD  
//等待子线程返回 f;qKrw  
try{ hVQ+ J!qD  
if(bFirst) BLYk <m  
{ V< 9em7
 
nFileLength = getFileSize(); O!@KM;  
if(nFileLength == -1) Td=]tVM  
{ 6A{s%v H  
System.err.println("File Length is not known!"); t'_,9  
} y:(C=*^<t  
else if(nFileLength == -2) ES2d9/]p-  
{ ^b/q|(Nu&  
System.err.println("File is not access!"); - KoA[
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} !x!L&p  
else _dRn0<#1(k  
{ VS@rM<K{  
for(int i=0;i<nStartPos.length;i++) 85d7IB{28  
{ pCud` :o"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); QKuc21  
} N]P*6sf-6  
for(int i=0;i<nEndPos.length-1;i++) [^"(%{H  
{ D%";!7u  
nEndPos = nStartPos[i+1]; 1.cUolnr  
} 75BO
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nEndPos[nEndPos.length-1] = nFileLength; MHzsxF|  
} c#4ZDjvm6  
} E&Zx]?~  
"e!$=;5  
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//启动子线程 nms<6kfzL  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p~{%f#V  
for(int i=0;i<nStartPos.length;i++) 2 3XAkpzp$  
{ ;*$8iwBQ_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ef1N#z%gt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), GE|^ryh  
nStartPos,nEndPos,i); <@;xV_`X+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d .l
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fileSplitterFetch.start(); ZkVvL4yIK  
} -u
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z ysUz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]ge^J3az$u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "Qm~;x2kB  
nEndPos = " + nFileLength); V IRv  
// fileSplitterFetch[nPos.length-1].start(); 5a/ A_..+I  
-|iA!w#31  
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//等待子线程结束 d)J] Y=j
 
//int count = 0; W$ d{  
//是否结束while循环 k=q%FlE  
boolean breakWhile = false; `OpC-Z&  
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9#$V1(}?  
while(!bStop) *Uw#  
{ 5]O LV1Xt  
write_nPos(); T>:g ME  
Utility.sleep(500); =v#A&IPA'  
breakWhile = true; %X-&yGY  
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for(int i=0;i<nStartPos.length;i++) mjr{L{H=?+  
{ ."@a1_F|  
if(!fileSplitterFetch.bDownOver) sMpC4E  
{ #__'U6`(  
breakWhile = false; !5 :1'$d]H  
break; \iTPJcb5  
} j$i8@]  
} HFCFEamBMP  
if(breakWhile) FYE9&{]h  
break; !z6/.>QJ~  
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p 7E{es|J  
//count++; n[p9$W`  
//if(count>4) F v^80M=z  
// siteStop(); ofhZ@3  
} `uJ l<kHI  
L\'qAfRZ  
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System.err.println("文件下载结束！"); s/'hLkxI  
} Qmh(+-Mp(  
catch(Exception e){e.printStackTrace ();} LCm}v&~%A  
} QMfy^t+I  
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//获得文件长度 |^9ig_k`  
public long getFileSize() KKTfxNxJn  
{ WiCM,wDi  
int nFileLength = -1; 4Fc1'  
try{ tf}Q%)`f  
URL url = new URL(siteInfoBean.getSSiteURL()); :zy'hu;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); thboHPml{  
httpConnection.setRequestProperty("User-Agent","NetFox"); nf@u7*#6  
M/`z;a=EP  
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int responseCode=httpConnection.getResponseCode(); ,OFr]74\  
if(responseCode>=400) K OHH74}_  
{ ,rPyXS9Sa{  
processErrorCode(responseCode); K`83C`w.  
return -2; //-2 represent access is error ?d`+vHK
]>  
} c15^<6]g  
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String sHeader; +}Wo=R
}  
3 AF]en  
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for(int i=1;;i++) .T>}O0L"  
{ ?)<XuMh  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); C+IE<=%F  
//Utility.log(in.readLine()); Qy,qQA/  
sHeader=httpConnection.getHeaderFieldKey(i); )/^$J
Yz  
if(sHeader!=null) ~ab_+%  
{ hWe}(Ks  
if(sHeader.equals("Content-Length")) L2A#OZZu  
{ W{/z-&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;|%JvptwW%  
break; 7anpz%  
} ~7H.<kJt  
} W5uI(rS<6  
else  0PbIWy'  
break; &;3z 1s/  
} (6^k;j  
} \gXx{rLW  
catch(IOException e){e.printStackTrace ();} *<j@+Ch  
catch(Exception e){e.printStackTrace ();} G{Q'N04
RA  
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Utility.log(nFileLength); *[YN|  
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return nFileLength; '$
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} J>PV{N  
>Tx;<G  
PFw"ICs  
//保存下载信息（文件指针位置） Ol0|)0  
private void write_nPos() b(Xg6
 
{ iROM?/$  
try{ dEL"(e#0s4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $8}'6,  
output.writeInt(nStartPos.length); Qq`\C0RZ  
for(int i=0;i<nStartPos.length;i++) /)|y+<E]}  
{ ,]"u!,yHb  
// output.writeLong(nPos); 8;NO>L/J]i  
output.writeLong(fileSplitterFetch.nStartPos); =*U24B*U93  
output.writeLong(fileSplitterFetch.nEndPos); K),wAZI!7j  
} xxn&{\ ?  
output.close(); g_X7@Dt  
} g7F Z -  
catch(IOException e){e.printStackTrace ();} dfcG'+RU}  
catch(Exception e){e.printStackTrace ();} xU"qB24]=  
} DV"ri  
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//读取保存的下载信息（文件指针位置） SLo/7$rct  
private void read_nPos() ?O?~|nI  
{ bm.H0rHR4  
try{ QD~`UJe>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 'b,D;'v  
int nCount = input.readInt(); c y$$}  
nStartPos = new long[nCount]; r&DK> H  
nEndPos = new long[nCount]; |i8dI)b  
for(int i=0;i<nStartPos.length;i++) Fgk/Ph3r  
{ %"2B1^o>
 
nStartPos = input.readLong(); lhTbgM  
nEndPos = input.readLong(); 4UkLvL1x  
} /B7 GH5  
input.close(); }6N|+z.cU  
} x6tY _lzJ  
catch(IOException e){e.printStackTrace ();} !W7ekPnK  
catch(Exception e){e.printStackTrace ();} ?J?!%Mw  
} e>)5j1  
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private void processErrorCode(int nErrorCode) MzG.Qh'z  
{ @=c='V]  
System.err.println("Error Code : " + nErrorCode); Nb1la
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} ')V5hKb^  
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u<zDZ{jt)  
//停止文件下载 u{,^
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public void siteStop() 0%/(p?]M  
{ 0iHI"9z  
bStop = true; Y."[k&P-  
for(int i=0;i<nStartPos.length;i++) ja
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fileSplitterFetch.splitterStop(); dr o42#$Mo  
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} TW0^wSm  
} KK?~i[aL  
//负责部分文件的抓取 ffVYlNQ7L  
**FileSplitterFetch.java 3R><AFMY?  
*/ (" %yV_R  
package NetFox; ! N p  
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import java.io.*; jp]JFh;3  
import java.net.*; O7sn>uO  
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public class FileSplitterFetch extends Thread { ~k3r$e@  
ijB,Q>TgO  
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String sURL; //File URL E=d[pI,e  
long nStartPos; //File Snippet Start Position 2LdV=ifq2S  
long nEndPos; //File Snippet End Position =l+p nG  
int nThreadID; //Thread's ID Yt^+31/%  
boolean bDownOver = false; //Downing is over 6z*L9Vy($  
boolean bStop = false; //Stop identical M~IiJ9{  
FileAccessI fileAccessI = null; //File Access interface .y!Hw{cq  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :xV&%Qa1  
{ 4 #N#[;M  
this.sURL = sURL; 4hs4W,2!  
this.nStartPos = nStart; +!(hd  
this.nEndPos = nEnd; |7-tUHMo[  
nThreadID = id; q.7CPm+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^ytd~iK8  
} ?H`LrL/k  
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public void run() e|LXH/H  
{ DxBt83e  
while(nStartPos < nEndPos && !bStop) &}uO ]0bR  
{ pK`rm"6G  
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try{ QWkw$mcf  
URL url = new URL(sURL); k<qQ+\X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); MqqS3   
httpConnection.setRequestProperty("User-Agent","NetFox"); a#1X)ot  
String sProperty = "bytes="+nStartPos+"-"; AN;?`AM;  
httpConnection.setRequestProperty("RANGE",sProperty); WA/\x  
Utility.log(sProperty); BhjXNf9[  
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InputStream input = httpConnection.getInputStream(); i@RjG
 
//logResponseHead(httpConnection); -1R~3j1_  
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byte[] b = new byte[1024]; [Dhc9  
int nRead; SYL$?kl  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) UnPSJ]VW  
{  P/Zo  
nStartPos += fileAccessI.write(b,0,nRead); 6D OE6  
//if(nThreadID == 1) @lX)dY  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OL>/FOH:Fx  
} 0[];c$r<  
uFqH_04  
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Utility.log("Thread " + nThreadID + " is over!"); Wac8x%J  
bDownOver = true; -=RXhE_{  
//nPos = fileAccessI.write (b,0,nRead); rtpjx%  
} &}FYz8w 2/  
catch(Exception e){e.printStackTrace ();} Qi%A/~  
} z 4-wvn<*  
} t^'1Ebg  
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//打印回应的头信息 [{ pc1U-  
public void logResponseHead(HttpURLConnection con) !>tXib]:  
{ .^uu*S_  
for(int i=1;;i++) (<CLftQKg  
{ ~(8A&!#,!  
String header=con.getHeaderFieldKey(i); ?aCR>AY5X  
if(header!=null) (GV6%l#I  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !EFd-fk  
Utility.log(header+" : "+con.getHeaderField(header)); ;kbz(:wA  
else 6$f,DU  
break; ZFzOW  
} S:d`z'  
} Q3DxjD  
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P'K')]D=!  
public void splitterStop() 4q[r KNl  
{ V= _8G3  
bStop = true; efhwbn  
} |'.SOm9)*  
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} =Yfs=+O  
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}S&{ &gh  
/* )fa  
**FileAccess.java Ort\J~O  
*//文件访问(定位，写) ZG>OT@ GA
 
package NetFox; >3bpa<M_  
import java.io.*; A!J5Wz>Q5  
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public class FileAccessI implements Serializable{ qg O)@B+  
ofSOy1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6f?DW-)jp/  
RandomAccessFile oSavedFile; WO{N
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long nPos; T \AuL  
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public FileAccessI() throws IOException M3Z yf  
{ , ^nUi c  
this("",0); S `[8TZ  
} aX|`G]PhdI  
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public FileAccessI(String sName,long nPos) throws IOException 'L,rJ =M3  
{ ReRRFkO"2  
oSavedFile = new RandomAccessFile(sName,"rw"); }PXWRv.gW  
this.nPos = nPos; f|`{PP`\  
oSavedFile.seek(nPos); YGHWO#!Gp  
} 2PC4EjkC  
gk&?h7P"<  
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public synchronized int write(byte[] b,int nStart,int nLen) #Kl;iY:n  
{ uYl ?Q  
int n = -1; LP\ Qwj{  
try{ @6gz)  p  
oSavedFile.write(b,nStart,nLen); o _-t/ ?  
n = nLen; 2vXMrh\  
} 3.jwOFH$  
catch(IOException e) LDNp
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{ OYKV*  
e.printStackTrace (); Qknd^%  
} i et|\4A  
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return n; yG_#>3sD+%  
} jIl-}/2  
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} ''6"Xi|5  
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/* ;?cUF78#  
**SiteInfoBean.java nQ+{1 C  
*/ MT*b+&1e  
package NetFox; &dS+!<3  
csV1ki/A  
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public class SiteInfoBean { jzV#%O{`  
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private String sSiteURL; //Site's URL 9qPP{K,Pq2  
private String sFilePath; //Saved File's Path +]{X-R  
private String sFileName; //Saved File's Name C }[u[)  
private int nSplitter; //Count of Splited Downloading File irm8z|N-  
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public SiteInfoBean() zbnQ
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{//nSplitter的缺省值为5 'FVT"M~  
//default value of nSplitter is 5 Ia\Nj _-%L  
this("","","",5); .UDZW*  
} b:
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p?`N<ykF<  
{ ,Q:dAe[ZsX  
sSiteURL= sURL; _#+9)*A  
sFilePath = sPath;
.{}t[U  
sFileName = sName; 2rH6ap  
this.nSplitter = nSpiltter; {> }U>V  
ANNL7Z3C  
ZO`d  
} 25TEbp[dy  
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i||YD-hkK  
public String getSSiteURL() !F8 !]"*  
{ lL^7x  
return sSiteURL; &a:aW;^A7  
} N+tS:$V  
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public void setSSiteURL(String value) 9+/|sU\.%  
{ 1@ina`!1O  
sSiteURL = value; u>
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} &yN<@.  
r
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public String getSFilePath() >!2'|y^  
{ ( r O j,D  
return sFilePath; ooAZ,l=8  
} ]+Vcuzq/  
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p*  
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public void setSFilePath(String value) ; YRZg|Zw  
{ k (R4-"@  
sFilePath = value; `MD/CFl4  
} jQDxbkIuzE  
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\Q$);:=qQ  
public String getSFileName() <uvshZv  
{ E%e-R6gl  
return sFileName; Q4x71*vy  
} ovohl<o\  
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public void setSFileName(String value) BO_^3Me*  
{ rQqtejcfx  
sFileName = value; 7[)(;-  
} ?/wloLS47  
9p.>L8  
f[RnL#*xJU  
public int getNSplitter() <Zi
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{ h(L5MZs  
return nSplitter; 9+:Trc\%N
 
} Wama>dy%  
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@^e@.)  
public void setNSplitter(int nCount) :uEp7Y4  
{ pIXQ/(h31  
nSplitter = nCount; wnX6XyUH  
} _e'mG'P(  
} *}J_STM  
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/* YV msWuF  
**Utility.java PjHm#a3zg%  
*/ fCfY.vd5  
package NetFox; [h1{{Nb#ez  
RBXoU'.  
:q=OW1^k^  
public class Utility { UQFuEI<1-  
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public Utility() -}J8|gwwp  
{ F\I^d]#,[  
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} ;vitg"Zh>  
d1
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//线程睡眠 93\,m+-  
public static void sleep(int nSecond) >MT)=4 9q  
{ g6V*w
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try{ <G>PPf}  
Thread.sleep(nSecond); N[-)c,O  
} *C BCQp[$  
catch(Exception e) 7h2bL6Y88  
{ <c#[.{A}s  
e.printStackTrace (); zCrcCr  
} YO,ldsSz|r  
} W}RR_Gu  
c'2ra/?k  
//日志 @jHio\/_  
public static void log(String sMsg) (R-Q9F+
;  
{ ~'3% Qr  
System.err.println(sMsg); je-s%kNlJ  
} B^9 #X5!  
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ZTZE_[  
public static void log(int sMsg) U&R$(k0zS  
{ @XmkIm  
System.err.println(sMsg); 67x^{u
7  
} jH1~Ve+q9  
} :X f3wP=  
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/* &U
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**TestMethod.java U:r2hqegd  
*/ OT i3T1&  
package NetFox; w3>|mDA}I  
vvxj{fxb)  
4(82dmKO  
public class TestMethod { ny={V*m  
R 28*  
c29Z1Zs2)  
public TestMethod() S<~nk-xr*h  
{ ///xx/weblogic60b2_win.exe /5Loj&!=  
try{  4&D="GA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @:B1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \`ReZu$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^%pwyY\t  
fileFetch.start(); sLIP|i  
} 4)I#[&f  
catch(Exception e){e.printStackTrace ();} v=VmiB
q[  
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}c%y0)fL
 
} ?miM15XI  
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"Ycd$`{Vgt  
public static void main(String[] args) 3G^Ed)JvE  
{ *.g?y6d  
new TestMethod(); EB<q.  
} m{c#cR  
} -::%9D}P|  
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