http断点续传简单实现（java)

/* *W4m3Lq  
**SiteFileFetch.java >BR(Wd.  
*/ oX#Q<2z*  
package NetFox; `slL%j
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import java.io.*; Yl4^AR&  
import java.net.*; M>wYD\oeg  
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public class SiteFileFetch extends Thread { yh Yb'GK  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )
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long[] nStartPos; //开始位置 Pu7_ v  
long[] nEndPos; //结束位置 F3N?Nk/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4,bv)Im+ `  
long nFileLength; //文件长度 ^ZvWR%  
boolean bFirst = true; //是否第一次取文件 sv: 9clJ  
boolean bStop = false; //停止标志 nno}e/zqf  
File tmpFile; //文件下载的临时信息 6LOn
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DataOutputStream output; //输出到文件的输出流 &vo--V1|  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） u!!Y=!y*<  
public SiteFileFetch(SiteInfoBean bean) throws IOException H{@Yo\J  
{ #o=y?(  
siteInfoBean = bean; j#X
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s[M
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); a=1NE
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if(tmpFile.exists ()) N+m)/x =:  
{ nGpXI\K  
bFirst = false; T}Km?d  
read_nPos(); xHUsFms  
} `n#H5Oyn  
else ZOft.P O  
{ In:9\7~jC  
nStartPos = new long[bean.getNSplitter()]; $h2){*5E{  
nEndPos = new long[bean.getNSplitter()]; mPOGidxix  
} K{x\4  
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} q$ZHd  
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public void run() ujDd1Bxf?  
{ C\S3Gs  
//获得文件长度 T_i:}ul  
//分割文件 $*SW8'],`  
//实例FileSplitterFetch AJf4_+He  
//启动FileSplitterFetch线程
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//等待子线程返回 Vr)<\h  
try{ b=g8eMm  
if(bFirst) 6DM$g=/'  
{ d:ARf  
nFileLength = getFileSize(); O-ew%@_  
if(nFileLength == -1) E[2m&3&  
{ N^#ZJoR  
System.err.println("File Length is not known!"); M}`B{]lLz  
} bt"W(m&f  
else if(nFileLength == -2) Ov};e  
{ Z,RzN5eN  
System.err.println("File is not access!"); r;/4F/6"  
} &qMPq->  
else M2HomO/X)  
{ iWRH{mK  
for(int i=0;i<nStartPos.length;i++) H(R1o~  
{ I CZ4A{I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); VYu~26Zr  
} qS403+Su1=  
for(int i=0;i<nEndPos.length-1;i++) dq7x3v^"ZG  
{ bHPYp5UwN  
nEndPos = nStartPos[i+1]; y-T| #  
} ^M3~^lV  
nEndPos[nEndPos.length-1] = nFileLength; rx $mk  
} r#+d&.|  
} lphFhxJA{  
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| h`0u'#  
//启动子线程 {HL3<2=o  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Y,GU%[+  
for(int i=0;i<nStartPos.length;i++) _p#CwExuy  
{ CKtB-a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), " W!M[qBW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Fw/6?:C}O6  
nStartPos,nEndPos,i); C+?Hm1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vqnw#U4`  
fileSplitterFetch.start(); Ipf|")*  
} 
!,l9@eJQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,LTH;<zB)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); VGfMN|h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @x9a?L.48  
nEndPos = " + nFileLength); yW+yg{Gg:  
// fileSplitterFetch[nPos.length-1].start(); `k=bL"T>\  
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//等待子线程结束 {s)+R[?m<o  
//int count = 0; q`|LRz&al  
//是否结束while循环 p`mS[bxv!  
boolean breakWhile = false; ~3UQ|j  
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while(!bStop) R?v>Q` Qi  
{ B||*.`3gN  
write_nPos(); $.C=H[QC  
Utility.sleep(500); :@kGAI  
breakWhile = true; &Flglj~7l  
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for(int i=0;i<nStartPos.length;i++) d{rQzia"mV  
{ A3rPt&<a  
if(!fileSplitterFetch.bDownOver) *7*lE"$p  
{ y#>,+a#5  
breakWhile = false; nnCGg+l  
break; wQv'8A_}  
} ie;]/va  
} rW0kA1=E  
if(breakWhile) ZZWD8AX  
break; cnSJ{T  
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V7
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//count++; xgABpikC^  
//if(count>4) rE iKi  
// siteStop(); WxW7qt  
} ~;Ov-^tp  
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System.err.println("文件下载结束！"); bQE};wM,  
} k xP-,MD  
catch(Exception e){e.printStackTrace ();} ?bPRxR  
} "XB[|#&  
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//获得文件长度 f_[<L  
public long getFileSize()
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{ L/wD7/ODr  
int nFileLength = -1; -0?~  
try{ 7P"| J\  
URL url = new URL(siteInfoBean.getSSiteURL()); c#a@n 4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M54j@_81pX  
httpConnection.setRequestProperty("User-Agent","NetFox"); H:!7:  
>G);j@Q  
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int responseCode=httpConnection.getResponseCode(); S7=Bd[4  
if(responseCode>=400) pV.
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{ Nqw&< x+  
processErrorCode(responseCode); >fe-d#!{  
return -2; //-2 represent access is error dOqOw M.y  
} Fp@TCPe#  
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String sHeader; eyefWn&  
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for(int i=1;;i++)
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{ d_4T}%q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }tsYJlh5  
//Utility.log(in.readLine()); p+l!6  
sHeader=httpConnection.getHeaderFieldKey(i); Ge,;8N88  
if(sHeader!=null) i%ZW3MrY~  
{ ld3-C55  
if(sHeader.equals("Content-Length")) +SsK21f"r  
{ ,$1eFgY%  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =g/{%;  
break; N5*u]j  
} ~7Ts_:E-  
} ?g?L3vRK  
else ,z3{u162  
break; VS9`{  
} '6Ay&A3N]  
} SxdE?uCUS  
catch(IOException e){e.printStackTrace ();} (ohq0Y  
catch(Exception e){e.printStackTrace ();} lrnyk(M}Q.  
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Utility.log(nFileLength); + ` s@  
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return nFileLength; !6s"]WvF  
} b'J'F;zh>  
L!
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_7IKzUn9g[  
//保存下载信息（文件指针位置） XEn*?.e  
private void write_nPos() _{R=B8Zz\  
{ '&.#  
try{ G"X8}:}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); R<sJ^n
x  
output.writeInt(nStartPos.length); qtiz a~u  
for(int i=0;i<nStartPos.length;i++) 4!+pc-}-  
{ _/Gczy4)#  
// output.writeLong(nPos); 6:q"l\n>  
output.writeLong(fileSplitterFetch.nStartPos); h.-@ F  
output.writeLong(fileSplitterFetch.nEndPos); v3}L`dyh3  
} Hu.t 3:w  
output.close(); ]4h92\\965  
} ~n[xtWO0  
catch(IOException e){e.printStackTrace ();} ox:[f9.5  
catch(Exception e){e.printStackTrace ();} Vm(1G8 a  
} GDu~d<RH  
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//读取保存的下载信息（文件指针位置） Lg~B'd8m  
private void read_nPos() IB# @yH  
{ ?sh
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try{ |;.o8}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \"CZI<=TB  
int nCount = input.readInt(); !PrwH
;  
nStartPos = new long[nCount]; _@ *+~9%8p  
nEndPos = new long[nCount]; N5]0/,I
}  
for(int i=0;i<nStartPos.length;i++) }b=}uiR#  
{ XK|R8rhg8`  
nStartPos = input.readLong(); si&S%4(  
nEndPos = input.readLong(); ]xX$<@HR  
}  emK$`9  
input.close(); Kl2lbe7  
} )\6&12rj  
catch(IOException e){e.printStackTrace ();} X5X?&* %{  
catch(Exception e){e.printStackTrace ();} 0j30LXI_  
} T/^Hz4uA7  
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private void processErrorCode(int nErrorCode) C0S^h<iSe*  
{ w"OP8KA:^T  
System.err.println("Error Code : " + nErrorCode); L3G \  
} X@k`3X  
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|tv"B@`  
//停止文件下载 mN!lo;m5  
public void siteStop() @O
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{ jeGj<m  
bStop = true; ]wKzE4Z/  
for(int i=0;i<nStartPos.length;i++) F)s{PCl  
fileSplitterFetch.splitterStop(); w3=%*<  
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pGf@z:^{*-  
} Mk=mT3=#  
} ~4s'0 w^  
//负责部分文件的抓取 KN tt  
**FileSplitterFetch.java JJ{9U(`_y6  
*/ (FJ9-K0b{n  
package NetFox; L=q+|j1>  
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import java.io.*; D\[h:8k  
import java.net.*; ~er\~kp  
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public class FileSplitterFetch extends Thread {
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String sURL; //File URL 3t<a $i
 
long nStartPos; //File Snippet Start Position <{2e#
Y  
long nEndPos; //File Snippet End Position !-N6l6N  
int nThreadID; //Thread's ID X66VU  
boolean bDownOver = false; //Downing is over ]da^xWK  
boolean bStop = false; //Stop identical INkD=tX  
FileAccessI fileAccessI = null; //File Access interface lu#LCG-.  
={5#fgK>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException TQ`Rk;0R  
{ Pb8^ b  
this.sURL = sURL; $<^u^q37u  
this.nStartPos = nStart; =QK$0r]c'k  
this.nEndPos = nEnd; wMdal:n^  
nThreadID = id; GrTulN?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6I!7c^]t  
} c%[#~;E  
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public void run() a)S+8uU  
{ ]~6_WE8L  
while(nStartPos < nEndPos && !bStop) $Bj;D=d@V  
{ -s|}Rh?Y  
 qNm$Fx  
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try{ UN%Vg:=  
URL url = new URL(sURL); ^S)cjH`P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Pt&(npjN,  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4'6`Ll|iq  
String sProperty = "bytes="+nStartPos+"-"; o99pHW(E  
httpConnection.setRequestProperty("RANGE",sProperty); ^)?d6nI  
Utility.log(sProperty); #7ov#_2Jd  
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InputStream input = httpConnection.getInputStream(); c-g)eV|)S  
//logResponseHead(httpConnection); @FC"nM  
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byte[] b = new byte[1024]; OKi\zS  
int nRead; k6Uc3O  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u~3%bJ]  
{ ]D@0|  
nStartPos += fileAccessI.write(b,0,nRead); l#lF +Q;  
//if(nThreadID == 1) &q`q4g&7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A8q;q2  
} 2MATpV#BT  
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Utility.log("Thread " + nThreadID + " is over!"); P ~#>H{  
bDownOver = true;
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//nPos = fileAccessI.write (b,0,nRead); xGU(n_Y  
} l3Lyea:  
catch(Exception e){e.printStackTrace ();} S a4W`  
} kN%MP6?J  
} &AlJ "N|  
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//打印回应的头信息 -F=v6N{  
public void logResponseHead(HttpURLConnection con) 6<'rG''  
{ iA0q_( \X  
for(int i=1;;i++) mo1oyQg8  
{ R|f~>JUF  
String header=con.getHeaderFieldKey(i); qim 'dp:  
if(header!=null) 7T"XPV|W6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); k{VE1@  
Utility.log(header+" : "+con.getHeaderField(header)); ?6nF~9Z'  
else y$3;$ R^  
break; $5v0m#[^  
} aA'|Rg,  
} Oky**B[D'  
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,=aJVb=C  
public void splitterStop() ]uspx[UIc  
{ xil[#W]7Ge  
bStop = true; 557(EM  
} wHIj<"2  
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} mKT>,M  
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}gkM^*$:%  
/* 6G}+gqbX  
**FileAccess.java PlYm&  
*//文件访问(定位，写) tX!nsm1  
package NetFox; *xE,sj+(  
import java.io.*; >|6iR%"f#  
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public class FileAccessI implements Serializable{ t+?P^Ok  
.XkMk|t8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 lQfL3`X!  
RandomAccessFile oSavedFile; .>wv\i[p  
long nPos; =?h~.lo  
7 Sa1;%R  
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public FileAccessI() throws IOException 2"fO6!hh  
{ +n
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this("",0); kQaSbpNmH  
} Mc-)OtmG[  
1
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public FileAccessI(String sName,long nPos) throws IOException T6pLoaKu  
{ *jMk/9oa<N  
oSavedFile = new RandomAccessFile(sName,"rw"); D0mI09=GtQ  
this.nPos = nPos; v`V7OD#:j]  
oSavedFile.seek(nPos); l;sy0S"DO]  
} Bm\qxQ  
;.wX@  
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public synchronized int write(byte[] b,int nStart,int nLen) l%Gw_0.?e  
{ bS >0DU   
int n = -1; 5'w^@Rs5  
try{ /%4_-Cpm  
oSavedFile.write(b,nStart,nLen); 5j0{p$'9  
n = nLen; W23]Bx  
} SEl#FWR  
catch(IOException e) u*7Z~R  
{ kkvtB<<Y  
e.printStackTrace (); \([WH!7  
} Z+pom7A"E  
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CC;! <km  
return n; 'cNKjL;  
} qzFQEepso  
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} e4I^!5)N  
O+=vEp(  
-Q;#sJ?  
/* +>7$4`Nb2  
**SiteInfoBean.java hF3&i=;.  
*/ 7([h4b
g{  
package NetFox; 0)Rw|(Fpo]  
/D_+{dtE  
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public class SiteInfoBean { M+wt__vHf  
#a| L3zR5v  
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private String sSiteURL; //Site's URL n:U>Fj>q  
private String sFilePath; //Saved File's Path 0Q593F  
private String sFileName; //Saved File's Name DWt*jX*  
private int nSplitter; //Count of Splited Downloading File 4$,,Ppn  
@c'|Iqy`  
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public SiteInfoBean() 9kKnAf4Z  
{//nSplitter的缺省值为5 D\^WXY5e%y  
//default value of nSplitter is 5 tvX>{-
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this("","","",5); Fv?=Z-wk  
} j%<}jw[2  
6AN)vs}  
yBLUNIr  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }<MR`h1  
{ +:6Ii9GN  
sSiteURL= sURL; Lt#'W  
sFilePath = sPath; rZ_>`}O2  
sFileName = sName;  VohhQ  
this.nSplitter = nSpiltter;
5)zn:$cz  
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} 7:h!Wj-a]  
,J mbqOV?!  
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public String getSSiteURL() '?o9VrO  
{ R*1kR|*_)  
return sSiteURL; *jzLFuWIG  
} "`A:(<x  
!c<wSQ,  
K:yr-#(P/  
public void setSSiteURL(String value) C9Bh@v%90^  
{ <Y'>F!?#  
sSiteURL = value; (I{ $kB"p  
} SQE[m9v  
,6
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(}!C4S3#  
public String getSFilePath() $e\N+~KNCy  
{ %@ mGK8  
return sFilePath; i(2y:U3[@  
} Z\>, ),O  
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mnF}S5[9  
public void setSFilePath(String value) P\~{3U  
{ ]*%+H|l  
sFilePath = value; X`zC^z}  
} eukA[nO7G  
!- ~X?s~L  
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public String getSFileName() ;n#%G^!H  
{ Aj"7q  
return sFileName; ]!YtH]
}  
} sCH)gr@gJ^  
v.Ogf5  
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public void setSFileName(String value) s[3fqdLP&  
{ ,[48Mspp  
sFileName = value; J/D|4fC  
} ),@f6](  
/k:$l9C[  
83]PA<R  
public int getNSplitter() 'bW5Fr>W  
{ ]]iO- }  
return nSplitter; v:ER4  
} ;Fl<v@9  
cep$_Ja  
~waNPjPRG  
public void setNSplitter(int nCount) M<8ML!N0;t  
{ )JgC$ <  
nSplitter = nCount; |qjZ38;6  
} c5i%(!>  
} ,axDMMDI  
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;q#]-^  
/* fu\s`W6f&  
**Utility.java iL?iz?+.%@  
*/ (fk5'  
package NetFox; "-i#BjZl/  
*:_~Nn9_R;  
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public class Utility { y62%26 [  
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18!VO4u\I  
public Utility() )Id2GV~2B  
{ zjM/M  
P{oAObP%  
~a+NJ6e1  
} <O857j  
`6w#8}  
//线程睡眠 V7<eQ0;m  
public static void sleep(int nSecond) Px4/O~bLk  
{ oNRG25  
try{ NCt
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Thread.sleep(nSecond); Up?=m^  
} we]>(|  
catch(Exception e) o42`z>~  
{ Pern*x9$  
e.printStackTrace (); {sc[RRN~C  
} a1x7~)z>zi  
} Z[IM<S9lz  
e6P[c=m #  
//日志 Rl@$xP  
public static void log(String sMsg) l)@:T|)c  
{ lmFA&s"m  
System.err.println(sMsg); F1u)i  
} #\FT EY!  
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:1<~}*B@{  
public static void log(int sMsg) ( tn< VK.  
{ X8 qIia  
System.err.println(sMsg); T_ ^C#>  
} W);W.:F  
} xh'^c^1  
#( uj$[o  
<'*4j\*  
/* qZ\L  
**TestMethod.java F'BdQk3o  
*/ CIQwl 6H9  
package NetFox; sJ6a7A8)  
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,YlQK;  
public class TestMethod { sv=^k(d3  
WN0c%kz=  
;QPy:x3  
public TestMethod() nPf'ee  
{ ///xx/weblogic60b2_win.exe ,f<B}O  
try{ ^ KAG|r9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YX;nMyD?~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); FzhT$7Gw  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i
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fileFetch.start(); BED@?:U#h  
} +qE']yzm!  
catch(Exception e){e.printStackTrace ();} Bcaw~WD  
bF6gBM@*  
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} 84Zgo=P}  
5; f\0<-  
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public static void main(String[] args) -3k;u  
{ 6Q$BUL}2?  
new TestMethod(); H-a^BZ&iU  
} -A;w$j6*  
} "^"'uO$
 
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