http断点续传简单实现（java)

/* p`dU2gV  
**SiteFileFetch.java 05#1w#i  
*/ PdFKs+Z`  
package NetFox; 1-uxC^u?|#  
import java.io.*; m9WDT  
import java.net.*; &ywPuTt  
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:RTC!spy  
public class SiteFileFetch extends Thread { 4Z=_,#h4.  
>2)OiQ`zg  
 DPxM'7  
SiteInfoBean siteInfoBean = null; //文件信息Bean r,3DTBe  
long[] nStartPos; //开始位置 ?3,:-"(@p  
long[] nEndPos; //结束位置 jOunWv|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ZQsJL\x[UK  
long nFileLength; //文件长度 1=c\Rr9]  
boolean bFirst = true; //是否第一次取文件 &{hL&BLr  
boolean bStop = false; //停止标志 L#{S!P,"  
File tmpFile; //文件下载的临时信息 IPKbMlV#d  
DataOutputStream output; //输出到文件的输出流 `AtBtjs RV  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） t|\%VC  
public SiteFileFetch(SiteInfoBean bean) throws IOException I*{nP)^9  
{ dL 1tl  
siteInfoBean = bean; 4[r0G+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); uBKgcpvTs  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5lmHotj#  
if(tmpFile.exists ()) kCF>nt@  
{ dq6m>;`  
bFirst = false; _/$Bpr{R  
read_nPos(); (N6i4 g6  
} kZ .gO  
else }'V5/>m[  
{ [PM2\#K  
nStartPos = new long[bean.getNSplitter()]; (Z q/  
nEndPos = new long[bean.getNSplitter()]; jD]~ AwRJ  
} 6I4\q.^qw  
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} sqwGsO$#  
jXx<`I+]  
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public void run() rQs)O<jl  
{ 8 +/rlHp  
//获得文件长度 (0r3/t?DQ  
//分割文件 L.2^`mZs  
//实例FileSplitterFetch ZohCP  
//启动FileSplitterFetch线程 
_ QI\  
//等待子线程返回 z+wA rPxc  
try{ G@\1E+Ip  
if(bFirst) &j`}vg  
{ / }X1W  
nFileLength = getFileSize(); '~<m~UXvD#  
if(nFileLength == -1) K`WywH3-  
{ Wx}8T[A}  
System.err.println("File Length is not known!"); %#:{UR)
E  
} yCR?UH;  
else if(nFileLength == -2) WIT>!|w_  
{ @Zu5VpJ  
System.err.println("File is not access!"); ,j{,h_Op  
} ) 1f~ dR88  
else Q#X8u-~  
{ Dlae;5D  
for(int i=0;i<nStartPos.length;i++) AaOuL,l  
{ F?*-4I-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,/%=sux  
} |Q6.299  
for(int i=0;i<nEndPos.length-1;i++) *8Xh(` Mj7  
{ ~O0 $Suv  
nEndPos = nStartPos[i+1]; y/{fX(aV  
} wC+u73599  
nEndPos[nEndPos.length-1] = nFileLength; HY*Kb+[  
} 9'giU r  
} SiRaFj4s"  
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w^|*m/h|@u  
//启动子线程 !4RWYMV"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Gbr=+AT  
for(int i=0;i<nStartPos.length;i++) 5h-SC
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{ Tod&&T'UW  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &\WSQmtto  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), BC#C9|n  
nStartPos,nEndPos,i); xp)sBM7A  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NZLxHD]mp  
fileSplitterFetch.start();  I<mV+ex  
}  :D6 ON"6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m)t;9J5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); b9J_1Gl]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]"hFC<w  
nEndPos = " + nFileLength); OJuG~euy  
// fileSplitterFetch[nPos.length-1].start(); wj^3N7_:w  
V)HG(k  
kR-SE5`Jk  
//等待子线程结束 O7m(o:t x3  
//int count = 0; mbTEp*H  
//是否结束while循环  i{NzV  
boolean breakWhile = false; }<v@01  
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while(!bStop) D9
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{ +T1pJ 89P  
write_nPos(); H9`)BbR  
Utility.sleep(500); %KlrSo  
breakWhile = true; x.!V^HQSN  
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for(int i=0;i<nStartPos.length;i++) {j?FNOJn  
{ *SDs;kg  
if(!fileSplitterFetch.bDownOver) N1}sHyVq7  
{ u<tbbKM  
breakWhile = false; yy^q2P  
break; '4+ ur`  
} {9&;Q|D z  
} !Y0Vid  
if(breakWhile) DrUO-  
break; i(%W_d!  
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//count++; }%ojw |  
//if(count>4) nLZTK&7}  
// siteStop(); pk$l+sNZ=  
} A5I)^B<(  
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{l1.2!  
System.err.println("文件下载结束！"); ifMRryN4  
} wo;~7K  
catch(Exception e){e.printStackTrace ();} 7Jyy z,!5  
} en4k/w_  
a od-3"7[  
|}s*E_/[  
//获得文件长度 b.Ju
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public long getFileSize() VK\X&Y3l  
{ jKAEm  
int nFileLength = -1; DZ'P@f)]  
try{ {0Yf]FQb-a  
URL url = new URL(siteInfoBean.getSSiteURL()); y*jp79G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jjB~G^n  
httpConnection.setRequestProperty("User-Agent","NetFox"); m<
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int responseCode=httpConnection.getResponseCode(); gZ3u=uME  
if(responseCode>=400) Xv5wJlc!d  
{ Ct<udO  
processErrorCode(responseCode); _/s$ZCd  
return -2; //-2 represent access is error *Mh
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} z;,u}u}aI  
c \J:![x  
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String sHeader; urs,34h  
[[Ls_ZL!=  
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for(int i=1;;i++) w>s,"2&5J  
{ .GPT!lDc  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); YNyk1cE  
//Utility.log(in.readLine());  j|DsG,  
sHeader=httpConnection.getHeaderFieldKey(i); ` xEx^P^7  
if(sHeader!=null) $kdB |4C  
{ g#pr yYz  
if(sHeader.equals("Content-Length")) O-0x8O^B  
{ ?DS@e@lx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r,8 [O  
break; x/
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} B?gOHG*vd>  
} $Ps|HN  
else Af~$TyX  
break; -e"H ^:  
} `t>l:<@%  
} iJ)_RSFK  
catch(IOException e){e.printStackTrace ();} 9IdA%RM~mH  
catch(Exception e){e.printStackTrace ();}
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Utility.log(nFileLength); T@H^BGs  
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return nFileLength; 7dTkp!'X-  
} Fbr;{T .
 
8+Lm's=W*  
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//保存下载信息（文件指针位置） +/4A  
private void write_nPos() 64 wv<r]5j  
{ IY
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try{ ,B*
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output = new DataOutputStream(new FileOutputStream(tmpFile)); [: n'k  
output.writeInt(nStartPos.length); +5g_KS  
for(int i=0;i<nStartPos.length;i++) a_^\=&?'  
{ xC?6v'  
// output.writeLong(nPos); ]Grek<  
output.writeLong(fileSplitterFetch.nStartPos); :".ARCg  
output.writeLong(fileSplitterFetch.nEndPos); s0TORl6Z|  
} :%_LpZ
 
output.close(); g{]0sn#  
} 8rAg\H3E  
catch(IOException e){e.printStackTrace ();} ,\W 8b-Z  
catch(Exception e){e.printStackTrace ();} -lr vKrt7  
} kf\PioD8  
^&9zw\x;z  
m^!Z_]A![  
//读取保存的下载信息（文件指针位置） xk9%F?)
 
private void read_nPos() L81ZbNU?$  
{ */5d>04  
try{ 7~G9'P<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .Bl\Z  
int nCount = input.readInt(); XFVE>
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nStartPos = new long[nCount]; KC*e/J  
nEndPos = new long[nCount]; y;m|  
for(int i=0;i<nStartPos.length;i++) i<C*j4qQ  
{ UP$.+<vm  
nStartPos = input.readLong(); w8")w*9Lmg  
nEndPos = input.readLong(); 9d0@wq.  
} =g7x' kN  
input.close(); nSDMOyj+  
} zH72'"w  
catch(IOException e){e.printStackTrace ();} m+`cS=-.  
catch(Exception e){e.printStackTrace ();} nI?[
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} :I.mGH!^  
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private void processErrorCode(int nErrorCode) OR P\b  
{ X~bX5b[P  
System.err.println("Error Code : " + nErrorCode); CImWd.W9~  
} `P@<3]  
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+  
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//停止文件下载 h]5(].  
public void siteStop() Q^P}\wb>  
{ nUaJz
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bStop = true; '&P%C" 5  
for(int i=0;i<nStartPos.length;i++) Y1w9y  
fileSplitterFetch.splitterStop(); v4!VrI  
%"i(K@  
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} ^`i#$  
} ^x]r`b  
//负责部分文件的抓取 :I]Mps<  
**FileSplitterFetch.java dohA0  
*/ i'<[DjMDlm  
package NetFox; 9Z$"K-G  
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import java.io.*; ''cInTCr  
import java.net.*; d"
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public class FileSplitterFetch extends Thread { ^do9*YejX;  
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String sURL; //File URL #Qw0&kM7I  
long nStartPos; //File Snippet Start Position .fqN|[>  
long nEndPos; //File Snippet End Position c1(RuP:S  
int nThreadID; //Thread's ID .|KyNBn  
boolean bDownOver = false; //Downing is over BiLY(1,  
boolean bStop = false; //Stop identical kM l+yli3c  
FileAccessI fileAccessI = null; //File Access interface G<zwv3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vQG5*pR*w  
{ |u% )gk  
this.sURL = sURL; ;J( 8 L  
this.nStartPos = nStart; Rxt^v+ ,$  
this.nEndPos = nEnd; 3lL-)<0A(  
nThreadID = id; F}yW/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ](]i 'fE>  
} [-1^-bb  
@}u*|P*  
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public void run() AEI>\Y  
{
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while(nStartPos < nEndPos && !bStop) Ys9[5@7  
{ caR<Kb:;*  
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try{ |)th1 UH  
URL url = new URL(sURL); *\a4wZ6<3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ah$b[\#C  
httpConnection.setRequestProperty("User-Agent","NetFox"); un"Gozmt5  
String sProperty = "bytes="+nStartPos+"-"; \##zR_%  
httpConnection.setRequestProperty("RANGE",sProperty); m#Jmdb_  
Utility.log(sProperty); q s!j>x  
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InputStream input = httpConnection.getInputStream(); .[KrlfI  
//logResponseHead(httpConnection); wc@X.Q[  
r| wS<cA2  
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byte[] b = new byte[1024]; MTh<|$   
int nRead; A0s ZOCky  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2eS~/Pq5=i  
{ =!A_^;NQf  
nStartPos += fileAccessI.write(b,0,nRead); %g$o/A$  
//if(nThreadID == 1) \A#41  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q~]uC2Mw  
} ?3`UbN:  
:K,i\  
T@B/xAq5!  
Utility.log("Thread " + nThreadID + " is over!"); U[-o> W#  
bDownOver = true; 9MJG;+B~  
//nPos = fileAccessI.write (b,0,nRead); 2%Ri,4SRb  
} =U9*'EFr  
catch(Exception e){e.printStackTrace ();} &vMb_;~B  
} / &5,3rU.G  
} r.&Vw|*>  
[#vH'y
  
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//打印回应的头信息 B)g[3gQ  
public void logResponseHead(HttpURLConnection con) h 0Q5-EA  
{ .o^l z 9:  
for(int i=1;;i++) e\l7Iu  
{ UYJZYP%r  
String header=con.getHeaderFieldKey(i); 13=AW  
if(header!=null) kd(8
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); `wEb<H  
Utility.log(header+" : "+con.getHeaderField(header)); 20h, ^  
else '3fu  
break; s?}e^/"v  
} H[$"+&q  
} xwq (N_  

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public void splitterStop() =z69e%.  
{ `p-cSxR_  
bStop = true; %)W2H^  
} &)ChQZA  
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} 0RLg:SV  
{rw|#Z>A  
&%DY\*  
/* ;bib/  
**FileAccess.java wKxtre(v  
*//文件访问(定位，写) dn
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package NetFox; }<SQ  
import java.io.*; E6ElNgL  
hx%v+/  

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public class FileAccessI implements Serializable{ ZhaP2pC%4  
v>)"HL"XG  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }q`S$P;  
RandomAccessFile oSavedFile; #OD/$f_  
long nPos; ,m:.-iy?  
WPMSm<[  
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public FileAccessI() throws IOException l<LI7Z]A  
{ AJ`h9%B  
this("",0); BM .~ 5\  
} JIOR4'9  
$ @`V  

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public FileAccessI(String sName,long nPos) throws IOException ChPmX+.i_  
{ vMH  
oSavedFile = new RandomAccessFile(sName,"rw"); Ckuh:bs  
this.nPos = nPos; <uw9DU7G  
oSavedFile.seek(nPos); 7'V@+5
 
} ZDYJ\}=  
EgCAsSx(  
.jE{3^  
public synchronized int write(byte[] b,int nStart,int nLen) U$ElV]N  
{ k"zv~`i'  
int n = -1; zE9W8:7  
try{ &.Qrs:U  
oSavedFile.write(b,nStart,nLen); 'XjZ_ng  
n = nLen; Vaw+.sG`AP  
} XJ| <?  
catch(IOException e) 7WS p($  
{ %RRNJf}z  
e.printStackTrace (); hRCJv#]HC  
} k(G^z   
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return n; WO>nIo5Y  
} A[{yCn`tM  
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} {]@= ijjf  
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/* P{>!5|k  
**SiteInfoBean.java )'cMYC  
*/ yjJ5>cg  
package NetFox; @:vwb\azVD  
`kXs;T6&  
y/7\?qfTk  
public class SiteInfoBean { xdt- ;w|  
Q\7h`d%)  
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private String sSiteURL; //Site's URL yq\K)g*=  
private String sFilePath; //Saved File's Path Y)2,PES=  
private String sFileName; //Saved File's Name p]+Pkxz]'  
private int nSplitter; //Count of Splited Downloading File >@_^fw)  
J<h$ wM  
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public SiteInfoBean() D'DfJwA  
{//nSplitter的缺省值为5 v^*K:#<Q!  
//default value of nSplitter is 5  >Abdd  
this("","","",5); 0=1T.4+=  
}
m&,(Jla  
`d`T*_  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) d^ 8ZeC#  
{
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sSiteURL= sURL; y??XIsF  
sFilePath = sPath; x g  
sFileName = sName; vX
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this.nSplitter = nSpiltter; '_FsvHQ  
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} =-n}[Y}A  
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9qzHS~l  
public String getSSiteURL() 0 /U{p,r6`  
{ Kis
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return sSiteURL; yWo; a  
} I1M%J@Cz  
[waIi3Dv\  
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public void setSSiteURL(String value) Iit;F  
{ Eo]xNn/g  
sSiteURL = value; 2pa5U;u:+  
} Lk}J8 V^2  
7~.9=I'A  
V {ddr:]
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public String getSFilePath() Dp-z[]})1  
{ ]Q)OL  
return sFilePath; DsCcK3 k  
} TKmf+ZT*r  
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'zuIBOH`j3  
public void setSFilePath(String value)
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{ >U27];}y  
sFilePath = value; R$[vm6T?  
} >!1-lfa8
 
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public String getSFileName() cIOlhX@  
{ Z,Dl` w  
return sFileName; M!D3}JRm  
} Y&Z.2>b
 

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public void setSFileName(String value) #?- wm  
{ Q sCheHP  
sFileName = value; B*Dz{a^.:  
} oQ[f,7
u  
G3AesTT|  
v;D~Pa  
public int getNSplitter() YO}<Ytx  
{ M&9+6e'-F  
return nSplitter; 60?%<oJ oH  
} T!)(Dv8@F  
PIS2Ed]  
-k"/X8  
public void setNSplitter(int nCount) P8/0H(,  
{ '3^'B03  
nSplitter = nCount; *_\_'@1|J)  
} Yufc{M00  
} $suzW;{#  
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B>P{A7Q  
/* aHK}sr,U  
**Utility.java w@w(-F!%l  
*/ U26}gT)  
package NetFox; 5vnrA'BhBU  
~6LN6}~|.  
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public class Utility { A;?|&`f  
RPL:-  
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public Utility() lA8`l>I  
{ ]Gq !`O1  
ml }{|Yz  
z9Rp`z&`E  
} 3eQ&F~S  
`*1p0~cu  
//线程睡眠 $kp{Eg '  
public static void sleep(int nSecond) hZt!/?dc  
{ Bh-ym8D  
try{ %:* YO;dw'  
Thread.sleep(nSecond); :&."ttf=  
} tf`^v6m%]  
catch(Exception e) ds[|   
{ qF;|bF  
e.printStackTrace (); 9V*qQS5<p  
} !'*-$e  
} c(s.5p ^  
xMG~N`r  
//日志 J<jy2@"tXo  
public static void log(String sMsg) M[,@{u/  
{ g{&ui.ml&  
System.err.println(sMsg); ^.QzQ1=D  
} k~1?VQ+?M  
#!+:!_45  
draN0vf  
public static void log(int sMsg) wNdisI  
{ V)N%WXG  
System.err.println(sMsg); kc&U'&RgY  
} \(2sW^fY  
} Z"fJ`--  
.U]-j\  
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/* 9CD_os\h  
**TestMethod.java H$UcF1k<  
*/ {F.[&/A  
package NetFox; ye5&)d"fa(  
E$p+}sP(C  
*b\t#meS&  
public class TestMethod { I9ep`X6Y  
&gx%b*;`L0  
Qq|57X)P*  
public TestMethod() f(MO_Sj]  
{ ///xx/weblogic60b2_win.exe Oxd]y1  
try{ 2g! +<YZ~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -6B4sZpzD  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); h(EhkCf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7J<5f)  
fileFetch.start(); QhJiB%M
 
} 8v%o,"  
catch(Exception e){e.printStackTrace ();} iGB}Il)  
 Mb~
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} $*fMR,~t&  
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public static void main(String[] args) P-"y3 ZE=  
{ ^k9I(f^c-_  
new TestMethod(); wI/iuc  
} F7#J
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} =B@2#W#  
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