http断点续传简单实现（java)

/* <@e+
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**SiteFileFetch.java /Fo/_=FE2  
*/ 3U~lI&  
package NetFox; J/x@$'  
import java.io.*; +:,`sdv6o  
import java.net.*; rFq@]t3q  
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public class SiteFileFetch extends Thread { t+ S
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SiteInfoBean siteInfoBean = null; //文件信息Bean %7]XW2u  
long[] nStartPos; //开始位置 .b#9q6F-/  
long[] nEndPos; //结束位置 2b#(X'ob  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 wVp4c?s  
long nFileLength; //文件长度 {x|kg;  
boolean bFirst = true; //是否第一次取文件 E./__Mz@  
boolean bStop = false; //停止标志 Sc/`=h]T  
File tmpFile; //文件下载的临时信息 :G`L3E&1s  
DataOutputStream output; //输出到文件的输出流 (H8C\%g:  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） MKe^_uF  
public SiteFileFetch(SiteInfoBean bean) throws IOException [{@zb-h  
{ [X }@Ct6  
siteInfoBean = bean; *vRI)
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J`r,_)J"2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {,Bb"0 \  
if(tmpFile.exists ()) L-z;:Ztk  
{ \oB'  
bFirst = false; X7H'Uk9:  
read_nPos(); `8Jq~u6_Z  
} Vm
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else /esVuz  
{ >:jM}*dnL  
nStartPos = new long[bean.getNSplitter()]; -MrtliepW*  
nEndPos = new long[bean.getNSplitter()]; Eq=wdI  
} 7 DY WdDX  
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} *qPdZ  
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public void run() }Kj Ju;  
{ W-z90k4Z5  
//获得文件长度 i,#k}CNu  
//分割文件 h`5YA89  
//实例FileSplitterFetch J%\
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//启动FileSplitterFetch线程 M@~~f   
//等待子线程返回 X&(<G  
try{ N-2([
v  
if(bFirst) FjZc#\^9  
{ E.J0fwyT  
nFileLength = getFileSize(); z.3<{-n}0i  
if(nFileLength == -1) ;8ET!&k*>E  
{ ?< cM^$lI>  
System.err.println("File Length is not known!"); @~k5+Z  
} 6Wpxp\  
else if(nFileLength == -2) WR/o @$/  
{ T-|9o|~z  
System.err.println("File is not access!"); gB>imr#e&  
} sno`=+|U]  
else ~)q g  
{ \ ]   
for(int i=0;i<nStartPos.length;i++) 4M}|/?<Br  
{ +VCo$
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); r{\BbUnf)  
} uf)W-Er6~  
for(int i=0;i<nEndPos.length-1;i++) J7BFk ?=  
{ ryxYcEM0  
nEndPos = nStartPos[i+1]; +T0op4  
} O' +"d%2'  
nEndPos[nEndPos.length-1] = nFileLength; Q2/MnM  
} L[?nST18%  
} Kt W6AZJ  
{p`mfEE(  
q,B3ru.?d  
//启动子线程 e>l,(ql  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; i:o}!RZ>  
for(int i=0;i<nStartPos.length;i++) ZFS7{:  
{
nbI=r+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AGOx@;w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I-b_h5ZD6  
nStartPos,nEndPos,i); d2rL 8jW  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \q~w<%9Dq  
fileSplitterFetch.start(); 0"EoC  
} hv*>%p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g(aZT#ii=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vSOT*0r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", EgTFwEj  
nEndPos = " + nFileLength);  ep+  
// fileSplitterFetch[nPos.length-1].start(); (1CJw:  
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4% HGMr  
//等待子线程结束 AL$W+')  
//int count = 0; bGv*-;*  
//是否结束while循环 L#D9@V'z  
boolean breakWhile = false; *q0`})IQ  
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#HeM,;Xp  
while(!bStop) q-3]jHChh  
{ ddsUz1%l  
write_nPos(); v:KX9A.  
Utility.sleep(500); b'i'GJBQ+$  
breakWhile = true; .~3kGf":  
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v"Me{+  
for(int i=0;i<nStartPos.length;i++) 6*IpA
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{ 0n3D~Xzd  
if(!fileSplitterFetch.bDownOver) XCDSmZ  
{ (}Sr08m  
breakWhile = false; 9
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break; nH@(Y&S  
} 8L%M<JRg~  
} ?^ZXU0IkP  
if(breakWhile) Y\xUT>(J7  
break; x?"#gK`3;  
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V!4a*,Pz  
//count++;
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//if(count>4) =SAV|  
// siteStop(); dpwD8Q< U  
} !@G)$g=<  
}j4
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System.err.println("文件下载结束！"); fXO_g  
} .NJ|p=fy  
catch(Exception e){e.printStackTrace ();} 9Bz0MUbrLl  
} <l$P&jSF3  
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//获得文件长度 -4w%I
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public long getFileSize() rK1-Mu  
{ Z!6UW:&~7  
int nFileLength = -1; ? -3\  
try{ )RN<GW'  
URL url = new URL(siteInfoBean.getSSiteURL()); ;QBh;jg4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j!\dn!Xwt  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?}}qu'N:N  
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int responseCode=httpConnection.getResponseCode(); 8d!GZgC8R  
if(responseCode>=400) Qzqc .T  
{ a+`D'?z  
processErrorCode(responseCode);  PWH^=K
 
return -2; //-2 represent access is error =E(#YCx  
} Z) Wnow  
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String sHeader; ExVDkt0  
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for(int i=1;;i++) m:uPEpcU  
{ +dk fcG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9sSN<7  
//Utility.log(in.readLine()); =su]w2,Iy  
sHeader=httpConnection.getHeaderFieldKey(i); .oqIZ\iik
 
if(sHeader!=null) hmpr%(c`  
{ 5.vG^T0w  
if(sHeader.equals("Content-Length")) `&!k!FZY*  
{ T%$jWndI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !^w E/  
break; Ipe n  
} DkD
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} k?*KnfVh!  
else _ \D"E>oM  
break; Y-)xTn  
} ${I*nh>=  
} +bA%  
catch(IOException e){e.printStackTrace ();} J0Z7l  
catch(Exception e){e.printStackTrace ();} 3BdX  
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***a2Z/(  
Utility.log(nFileLength); uo2'"@[e  
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return nFileLength; tGjhHp8}c  
} D+JAK!W  
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k7@t{Cu0D&  
//保存下载信息（文件指针位置） >Lft9e   
private void write_nPos() 8`=v.   
{ s@8w-]"  
try{ w(9*7pp  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ",yc0 2<  
output.writeInt(nStartPos.length);
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for(int i=0;i<nStartPos.length;i++) q_V0+
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{ PLX>-7@  
// output.writeLong(nPos); =-"c*^$]  
output.writeLong(fileSplitterFetch.nStartPos); NX[4PKJ0C  
output.writeLong(fileSplitterFetch.nEndPos); /Fgw$ ^H  
} dOFD5}_   
output.close(); .ubE2X[][  
} kLj$@E`4  
catch(IOException e){e.printStackTrace ();} %<0eA`F4  
catch(Exception e){e.printStackTrace ();} z//VlB  
} ?'s6Xmd  
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//读取保存的下载信息（文件指针位置） q?):oJ  
private void read_nPos() KC`q#&dt  
{ G2Vv i[c  
try{ P 43P]M2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0[Ht_qxb  
int nCount = input.readInt(); rx0~`cVV:  
nStartPos = new long[nCount]; xtfBfA  
nEndPos = new long[nCount]; i,IB!x  
for(int i=0;i<nStartPos.length;i++) v&a4^s  
{ W,XTF  
nStartPos = input.readLong(); Djq!P  
nEndPos = input.readLong(); \$sjrqKnu  
} A9BX_9}]  
input.close(); ,m_WR7!$E  
} ZfrVjUB  
catch(IOException e){e.printStackTrace ();} IQZ#-)[T"  
catch(Exception e){e.printStackTrace ();} CVNj-&vj  
} bi[IqU!9  
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private void processErrorCode(int nErrorCode) 4_A0rveP  
{
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System.err.println("Error Code : " + nErrorCode); U8.7>ENnP&  
} _>+8og/%@  
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+{<#(}  
//停止文件下载 ^D%FX!$  
public void siteStop() ziPR>iz-  
{ ",6M)3{|c  
bStop = true; #>lG7Ns|4  
for(int i=0;i<nStartPos.length;i++) #J (~_%Wi  
fileSplitterFetch.splitterStop(); JN+_|`  
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} El\%E"Tk%  
} yAL[[  
//负责部分文件的抓取 GZI`jS"lU  
**FileSplitterFetch.java 'k;rH!R  
*/ s\!>"J bAQ  
package NetFox; 3?2 FP|G8  
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import java.io.*; Guz"wY  
import java.net.*; KlRr8G!Z  
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public class FileSplitterFetch extends Thread { }>)[<;M>%  
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String sURL; //File URL X
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long nStartPos; //File Snippet Start Position 8
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long nEndPos; //File Snippet End Position OC-gA}FZ-}  
int nThreadID; //Thread's ID }PTV] q%  
boolean bDownOver = false; //Downing is over `x%'jPP1^  
boolean bStop = false; //Stop identical WSuw
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FileAccessI fileAccessI = null; //File Access interface fhL,aCS=  
nt*Hc1I  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException MxT-1&XL  
{ |$?bc3  
this.sURL = sURL; _ODbY;M  
this.nStartPos = nStart; ,eTU/Q>{,&  
this.nEndPos = nEnd; T5a*z}L5  
nThreadID = id; h1'\:N`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pe^u
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} ns6(cJ^a  
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public void run() D$t k<{)oB  
{ ^#-nE7  
while(nStartPos < nEndPos && !bStop) DI+fwXe
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{ qkiI/nH3  
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try{ t+9][Adf  
URL url = new URL(sURL); v`M3eh@$A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dKdj`wB  
httpConnection.setRequestProperty("User-Agent","NetFox"); |yx6X{$k  
String sProperty = "bytes="+nStartPos+"-"; 8F._9U-EN  
httpConnection.setRequestProperty("RANGE",sProperty); FCnm1x#  
Utility.log(sProperty); hCC<?5q  
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InputStream input = httpConnection.getInputStream(); C=eF.FB;'  
//logResponseHead(httpConnection); yu;P +G  
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byte[] b = new byte[1024]; Oil?JI Hq  
int nRead; euC&0Ee2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Hv2De0W  
{ j KoG7HH  
nStartPos += fileAccessI.write(b,0,nRead); V$
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//if(nThreadID == 1) +0OLc2 )w  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2 B  
} p6;OL@\~  
,^C--tgZJg  
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Utility.log("Thread " + nThreadID + " is over!"); YJ\Xj56gv  
bDownOver = true; /Njd[=B  
//nPos = fileAccessI.write (b,0,nRead); g*_cPU0~m  
} VIv&ofyAR  
catch(Exception e){e.printStackTrace ();} <ZNzVnVA  
} RS8Hf~0G  
} \SBc;  
b:TLV`>/&  
!qWH`[:  
//打印回应的头信息 ~^1{B
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public void logResponseHead(HttpURLConnection con) CLU
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{ c-(UhN3WG  
for(int i=1;;i++) ]7RD"}  
{ d8c=L8~jt  
String header=con.getHeaderFieldKey(i); R^Y <RI  
if(header!=null) _no*k?o*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?vbvBu{a  
Utility.log(header+" : "+con.getHeaderField(header)); Z'.AAOG  
else ~XOTs  
break; xCc[#0R{  
} fTK3,s1=  
} ?`PvL!'  
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public void splitterStop() C$XU%5qi  
{ 
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bStop = true; 67Th;h*sh  
} OWg(#pZk  
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} \RC'XKQ*n  
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/* RO'7\xvn  
**FileAccess.java }E50>g  
*//文件访问(定位，写) V<T9&8l+:  
package NetFox; <h:x=  
import java.io.*; P&*2pX:  
@emK1iwm  
t*1fLumXR  
public class FileAccessI implements Serializable{ rWR}Stc@
]  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ',JinE95  
RandomAccessFile oSavedFile; 0tT(W^ho g  
long nPos; :&V h?  
?kbiMs1;u  
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public FileAccessI() throws IOException >I-RGW'A  
{ *Doa*wQ  
this("",0); LnH?dy  
} CYY=R'1:G{  
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public FileAccessI(String sName,long nPos) throws IOException "&G/T ?4  
{ Ku5\]  
oSavedFile = new RandomAccessFile(sName,"rw");  3KlbP  
this.nPos = nPos; gd`!tRcNY  
oSavedFile.seek(nPos); i@"@9n~  
} M_/7D|xl/T  
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public synchronized int write(byte[] b,int nStart,int nLen) [+n*~
  
{ o,AAC
  
int n = -1; A$Hfr8w1u  
try{ R{
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oSavedFile.write(b,nStart,nLen); Q ayPo]O  
n = nLen; jaII r06  
} v3~?;f,l  
catch(IOException e) hKL4cpK4  
{ f!Y?S  
e.printStackTrace (); 5YE'L.  
} DgId_\Ze  
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;-~B)M_S`  
return n; L*xhGoC=  
} 6t[+pL\b  
7)`nD<j5  
 mHdA2  
} i&bA2p3+d  
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/* Yvw(tj5_5  
**SiteInfoBean.java ! >(7+B3E*  
*/ GfoLae  
package NetFox; [8 ]z|bM  
@\0ez<.p}  
A5c%SCq;
 
public class SiteInfoBean { KX,S  
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private String sSiteURL; //Site's URL iVhJ t#_b  
private String sFilePath; //Saved File's Path >E;uU[v)I  
private String sFileName; //Saved File's Name \A 2r]  
private int nSplitter; //Count of Splited Downloading File _|kxY'_[8  
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public SiteInfoBean() /M1ob:m  
{//nSplitter的缺省值为5 ey7 f9  
//default value of nSplitter is 5 +h|`/ &,  
this("","","",5); %(3|R@G.  
} DE}K~}sbd  
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+rd|A|hRq  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) vyNxT*,[K  
{ kbX8$xTM  
sSiteURL= sURL; 4Tb #fH%  
sFilePath = sPath;
HSjlD{R  
sFileName = sName; LO9=xGj.  
this.nSplitter = nSpiltter; cLpYW7vZ[  
?pW`cFLDHF  
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} eVjBGJ=2e  
<=zQ NBtx  
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public String getSSiteURL() !![DJ  
{ W,V:R  
return sSiteURL; c69C  
} lk/n}bx  
!#], hok8X  
oR)Jznmi}  
public void setSSiteURL(String value) @Q)OGjaq  
{ @'#,D!U  
sSiteURL = value; UdT*E: 6  
} %a>&5V  
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@>
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public String getSFilePath() >c1qpk/  
{ `x+ B+)0X  
return sFilePath; *'
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} n`? py
 
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xK *b1CB  
public void setSFilePath(String value) Qf~vZtJ+J  
{ ~Z\8UsVN  
sFilePath = value; c,np2myd  
} u@Ih GME  
\pa"%c)  
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public String getSFileName() ?ZV/U!y  
{ 6KXtcXQ  
return sFileName; /hr7NT{e%v  
} hQ,ch[j'  
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public void setSFileName(String value) kvL=> A  
{ !j9t*2m[  
sFileName = value; x,=&JtKVc  
} ;5]Lf$tZ  
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9'fQHwsJ  
public int getNSplitter() Bd!bg|uO*  
{ Z^bQ^zk-  
return nSplitter; ,;EIh}  
}  :|>h7v  
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public void setNSplitter(int nCount) h{)kQLuzT  
{ ep!Rf:  
nSplitter = nCount; H[6:_**?o  
} ]~Rho_mq#  
} JrJo|0Q  
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/* S]}nm  
**Utility.java %|s;C  
*/ }n]
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package NetFox; ;,hwZZ
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public class Utility { XQY#716)  
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public Utility() ]i|h(>QWP  
{ cq,SP&T~
 
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} 3lf=b~Zi
)  
n<Z({\9&H  
//线程睡眠 tIWmp30S  
public static void sleep(int nSecond) |6.l7u?d  
{ p2hB8zL  
try{ =mO vs  
Thread.sleep(nSecond); GA$V0YQX  
} `LrHKb aP  
catch(Exception e) bBiE  
{ JgxtlYjl  
e.printStackTrace (); M,j U}yD3  
} aZH:#lUlj  
} bZ dNi
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@3>u@  
//日志 f/U`  
public static void log(String sMsg) W\>fh&!)  
{ Cz9xZA{[M  
System.err.println(sMsg); ,kyJAju>  
} $jjfC  
p\Q5,eg  
_'#n6^Us<  
public static void log(int sMsg) ayn)5q/z  
{ :">!r.Q  
System.err.println(sMsg); Uf1!qP/H?  
} [zH:1Zhl&  
} ncZ+gzK|"  
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/* "H=6j)Cb  
**TestMethod.java Jz\%%C  
*/ 6gL#C&  
package NetFox; C(eTR1  
j@AIK+0Qc  
?fQ'^agq  
public class TestMethod { @bi}W`  
RF`.xQ26=  
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public TestMethod() )%`c_FL@N=  
{ ///xx/weblogic60b2_win.exe &DS/v)]  
try{ g&^quZ"H  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); B~'vCuE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j%Y#(Q>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =Z{O<xw'  
fileFetch.start(); |T<_5Ik  
} 8Q.T g.  
catch(Exception e){e.printStackTrace ();} ])[[ V!1  
$By<$  
8^kGS-+^  
} /}((l%UE.  
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public static void main(String[] args) ^4y,W]JUDt  
{ 6,^>mNm  
new TestMethod(); kVuUjP6(c  
} fJ=
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} sSr&:BOsi  
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