http断点续传简单实现（java)

/* '.d]n(/lZd  
**SiteFileFetch.java rgXD>yu(  
*/ K^+}__;]  
package NetFox; q.NvwJ  
import java.io.*; ,N`D{H"F  
import java.net.*; M[,G#GO  
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public class SiteFileFetch extends Thread { cp<jwcc!  
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SiteInfoBean siteInfoBean = null; //文件信息Bean lF
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long[] nStartPos; //开始位置 !0 -[}vvU  
long[] nEndPos; //结束位置 '7TT4~F  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 d3K-|  
long nFileLength; //文件长度 Q!"W)tD  
boolean bFirst = true; //是否第一次取文件 ,7|Wf %X  
boolean bStop = false; //停止标志 SjB#"A5  
File tmpFile; //文件下载的临时信息 ]<?7CpP  
DataOutputStream output; //输出到文件的输出流 mL[Y{t#N  
*IBCThj  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） u3@v  
public SiteFileFetch(SiteInfoBean bean) throws IOException e&J_uG  
{ qI#ow_lL#  
siteInfoBean = bean; 6b9&V`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;gNoiAxW  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 52d8EGC  
if(tmpFile.exists ()) ZMI vzQYI  
{ N"rZK/@}  
bFirst = false; dt|f4XWF  
read_nPos(); ~6-6aYhe  
} qb1[-H  
else {kp^@  
{ %e'Z.vm  
nStartPos = new long[bean.getNSplitter()]; 2%(RB4+  
nEndPos = new long[bean.getNSplitter()]; Ig M_l=  
} F(#~.i  
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} #Bgq]6G2  
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public void run() nH% 1lD?:  
{ y O
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//获得文件长度 K7N.gT*4  
//分割文件 a5xmIp@6  
//实例FileSplitterFetch "ZLujpZcG  
//启动FileSplitterFetch线程 +1j+%&).  
//等待子线程返回 njN]0l{p  
try{ mtn+bV R%  
if(bFirst) %:WM]dc  
{ '4}c1F1T_  
nFileLength = getFileSize(); CiSl0  
if(nFileLength == -1) Yab=p 9V;;  
{ ~ GW8|tw  
System.err.println("File Length is not known!"); "~HV!(dRMC  
} '{(/C?T  
else if(nFileLength == -2) xMAb=87_  
{ cXo^.
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System.err.println("File is not access!"); Zc9j_.?*  
} dn)pVti_  
else }^R_8{>k  
{ Jf{ M[ z  
for(int i=0;i<nStartPos.length;i++) @*rED6zH  
{ b[_${in:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5};$>47m  
} .A2u7*h&  
for(int i=0;i<nEndPos.length-1;i++) \<R.F  
{ _cW6H B^j  
nEndPos = nStartPos[i+1]; ~8 w(M  
} M?fRiOj  
nEndPos[nEndPos.length-1] = nFileLength; /K@{(=n  
} ?dcR!-3  
} q"Z!}^{  
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~  
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//启动子线程 $=-Q]ld&]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ']]&<B}mz  
for(int i=0;i<nStartPos.length;i++) GXE6=B
O  
{ ,$qqHSd1M  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qm&Z_6Pw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4/Bn9F  
nStartPos,nEndPos,i); %g<J"/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }_{QsPx9  
fileSplitterFetch.start(); (s\":5 C  
} 0fd\R_"d.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U~w g'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); MN22#G4j^w  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", m*^|9*dIC  
nEndPos = " + nFileLength); mzX <!  
// fileSplitterFetch[nPos.length-1].start(); l6S6Y  
&PAgab2$  
%VCfcM}5I  
//等待子线程结束 1xkU;no  
//int count = 0; #1C~i}J1  
//是否结束while循环 Q$(0Nx<  
boolean breakWhile = false; n*oa J<o%  
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<XH

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while(!bStop) "n3i(sZ  
{ ;5.o;|w?!  
write_nPos(); 6!3Jr  
Utility.sleep(500); aumXidbS  
breakWhile = true; o,sw[  
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for(int i=0;i<nStartPos.length;i++) joN}N}U  
{ Z{w{bf1&A  
if(!fileSplitterFetch.bDownOver) "k${5wk#Fl  
{ yeCR{{B/'  
breakWhile = false;
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break; f2#9E+IQ  
} R "&(Ae?LR  
} /Lc= K<  
if(breakWhile) 2z\4?HJy  
break; Uq,M\V\  
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Vd{h|=J  
//count++; #NVqS5  
//if(count>4) ] _/d  
// siteStop(); YW}1iT/H  
} Iy}r'#N  
$DfaW3bJ  
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System.err.println("文件下载结束！"); ')9%eBaeK  
} y%H;o?<WX  
catch(Exception e){e.printStackTrace ();} |-zwl8E  
} sX&M+
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S%ri/}qI[{  
h]94\XQ>$  
//获得文件长度 rI:
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public long getFileSize() k"P2J}4eO  
{ O8+[)+6^  
int nFileLength = -1; 4JHQ^i-aY  
try{ Or9@X=C  
URL url = new URL(siteInfoBean.getSSiteURL()); ~EU[?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f$E66yG
 
httpConnection.setRequestProperty("User-Agent","NetFox"); ~PNO|]8j  
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kCR)k=*  
int responseCode=httpConnection.getResponseCode(); FGOa!G  
if(responseCode>=400) !40t:+I  
{ gkpNT)  
processErrorCode(responseCode); wYf=(w\c  
return -2; //-2 represent access is error ] %*970  
} H&L=WF+x  
U
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String sHeader; Ssu{Lj  
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for(int i=1;;i++) tji,by#E/%  
{ !dL
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LIH>IpamN  
//Utility.log(in.readLine()); J1<fE(X  
sHeader=httpConnection.getHeaderFieldKey(i); JXeqVKF  
if(sHeader!=null) YF{K9M!  
{ e76@-fg  
if(sHeader.equals("Content-Length")) ![5<\  
{ UBRMV s  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (Df<QC`0v  
break; bq4H4?j  
} 'w%N(Ntq  
} JMOP/]%D  
else !9"R4~4  
break; {I 7pk6Qd  
} P:k(=CzZ@J  
} `OQ&u  
catch(IOException e){e.printStackTrace ();} {NK>9phoB  
catch(Exception e){e.printStackTrace ();} ;_i0@@J  
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Utility.log(nFileLength); ) Q=G&  
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return nFileLength; LbR/it'}  
} RQ,(?I*8\  
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!E_uQ?/w]Z  
//保存下载信息（文件指针位置） z K8#gif@  
private void write_nPos() ~DZ;l/&Mz7  
{ p2~Q  
try{ w=e,gNO  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6sy%KO*A  
output.writeInt(nStartPos.length); F'CUkVC0~P  
for(int i=0;i<nStartPos.length;i++) >2syF{`j  
{ f9- |!]s  
// output.writeLong(nPos); z%/ww7H  
output.writeLong(fileSplitterFetch.nStartPos);
hqD;<:.  
output.writeLong(fileSplitterFetch.nEndPos); lO $M6l  
} 0]oQ08  
output.close(); 3R#<9O  
} W,{`)NWg  
catch(IOException e){e.printStackTrace ();} _R(5?rG,  
catch(Exception e){e.printStackTrace ();} p>eD{#2  
} xYu~}kMu  
@?]-5~3;  
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//读取保存的下载信息（文件指针位置） UuT[UB=x5  
private void read_nPos() )N=b<%WD  
{ /1li^</|p`  
try{ G0s:Dum  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A}y1v;FB  
int nCount = input.readInt(); P)ZSxU  
nStartPos = new long[nCount]; S,(@Q~  
nEndPos = new long[nCount]; g[M@  
for(int i=0;i<nStartPos.length;i++) T4!]^_t^  
{ NuO
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nStartPos = input.readLong(); <uTsXv  
nEndPos = input.readLong(); 3X!~*_iC  
} $
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input.close(); pO+1?c43
 
} 2FVKgyV  
catch(IOException e){e.printStackTrace ();} h5F'eur  
catch(Exception e){e.printStackTrace ();} <Ab:yD`K!  
} 1M;)$m:  
@J<B^_+Se  
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private void processErrorCode(int nErrorCode) [d&Faa[`  
{ Fc
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System.err.println("Error Code : " + nErrorCode); NUnP'X=J,  
} a+~o: 5  

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//停止文件下载 \7j)^  
public void siteStop() kxn;;  
{ *i?qOv/=>  
bStop = true; `X^e}EGWu  
for(int i=0;i<nStartPos.length;i++) YqJIp. Z  
fileSplitterFetch.splitterStop(); Ez$5wY^J  
n#&RY%#`  
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} \QM
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}
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//负责部分文件的抓取 'j3'n0o  
**FileSplitterFetch.java wKeqR$  
*/  yY| .  
package NetFox; %@&)t?/=  
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7.Mh$?;i9  
import java.io.*; /*O,T  
import java.net.*; O^xt  
*tO<wp&  
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public class FileSplitterFetch extends Thread { (;j7{(  
a2rv4d=  
#`fT%'T!  
String sURL; //File URL m5p~>]}fYF  
long nStartPos; //File Snippet Start Position "/'=gE  
long nEndPos; //File Snippet End Position k`AJ$\=  
int nThreadID; //Thread's ID >gSerDH8\  
boolean bDownOver = false; //Downing is over %xfy\of+Nk  
boolean bStop = false; //Stop identical j&Aq^aI  
FileAccessI fileAccessI = null; //File Access interface F:@Ixk?E  
}6bLukv  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h[8y$.YsC  
{ 1%@~J\qF  
this.sURL = sURL; tQ~B!j]  
this.nStartPos = nStart; 0\#Q;Z2  
this.nEndPos = nEnd; % *G)*n  
nThreadID = id; `@eH4}L*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ( 7?%Hg  
} 9>#|~P&FE  
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public void run() biG9?  
{ 84[^#ke  
while(nStartPos < nEndPos && !bStop) 4r. W:}4:  
{ 19.cf3Dh  
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try{ O%&@WrFq  
URL url = new URL(sURL); 1 ~7_!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C#~MR+;  
httpConnection.setRequestProperty("User-Agent","NetFox"); `aUp&8{  
String sProperty = "bytes="+nStartPos+"-"; @,MdvR+a  
httpConnection.setRequestProperty("RANGE",sProperty); 
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Utility.log(sProperty); vOK;l0%  
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InputStream input = httpConnection.getInputStream(); '/H(,TM
 
//logResponseHead(httpConnection); AVr!e   
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byte[] b = new byte[1024]; RF)B4D-W  
int nRead; `0^i #  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *jK))|%  
{ i-?zwVmn  
nStartPos += fileAccessI.write(b,0,nRead); @;6}xO2  
//if(nThreadID == 1) y2R=%EFh6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); re!8nuBsA  
} %-l:_A  
|&Pl4P  
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Utility.log("Thread " + nThreadID + " is over!"); BB.TrQM.#  
bDownOver = true; a+/|O*>#  
//nPos = fileAccessI.write (b,0,nRead); >y9o&D  
} \`zG`f  
catch(Exception e){e.printStackTrace ();} yU|ji?)e  
} uB1!*S1f  
} fqb$_>3Ol  
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//打印回应的头信息 3-bcY4  
public void logResponseHead(HttpURLConnection con) `&_k\/  
{ @(c<av?  
for(int i=1;;i++) 5S]P#8  
{ `5-#M/J  
String header=con.getHeaderFieldKey(i); FA9e(Ha   
if(header!=null) w.aFaR)04  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
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Utility.log(header+" : "+con.getHeaderField(header)); ~It+|X=Kx  
else M:M>@|)  
break; A{2$hKqHi  
} txo?k/w  
} vB5iG|b}  
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public void splitterStop() [T]qm7 ?  
{ O{#Cddt:r  
bStop = true;
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} X-$td~r  
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} !>y}Xq{bm3  
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/* xqWrW)  
**FileAccess.java |/^aLj^u  
*//文件访问(定位，写) 1vs>2` DLa  
package NetFox; WlQ=CRY  
import java.io.*; 6Y)^)dOi  
!*Z)[[  
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public class FileAccessI implements Serializable{ **r?   
,,_K/='m  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |D`b
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RandomAccessFile oSavedFile; Y"kS!!C>[  
long nPos; u7zB9iQ&  
8+a<#?;  
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public FileAccessI() throws IOException xO<-<sRA  
{ `$Flgp0P  
this("",0);
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} Zmbz-##HQ  
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public FileAccessI(String sName,long nPos) throws IOException qm8n7Z/  
{ ~oA9+mT5  
oSavedFile = new RandomAccessFile(sName,"rw"); m2uML*&O5K  
this.nPos = nPos; 8N* -2/P&  
oSavedFile.seek(nPos); 5rA!VES T  
} +'j*WVE%5  
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public synchronized int write(byte[] b,int nStart,int nLen) tD7C7m  
{ 8^/Ek<Qb|  
int n = -1; O;BMwg_7  
try{ 6a]f
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oSavedFile.write(b,nStart,nLen);
oB06{/6  
n = nLen; 0/P-> n~  
} mz$Wo *FB  
catch(IOException e) v#%>uLl  
{ {9.~]dI|L  
e.printStackTrace (); <fsn2[V:B%  
} iC|6roO!jk  
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return n; ZYR,8y  
} aQ&8fteFR  
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} }Q r0T  
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/* ?sf2h:\N  
**SiteInfoBean.java =PKt09b
^  
*/ />^`*e_  
package NetFox; -=[o{r`  
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public class SiteInfoBean { C+(Gg^ w  
Z>Kcz^a#  
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private String sSiteURL; //Site's URL <W=[ sWJ  
private String sFilePath; //Saved File's Path #!=>muZt  
private String sFileName; //Saved File's Name a[P>SqT4`  
private int nSplitter; //Count of Splited Downloading File F{*9[jY  
?V5Pt s  
!/Bw,y ri<  
public SiteInfoBean() Avv  
{//nSplitter的缺省值为5 *Nf4bH%MN  
//default value of nSplitter is 5 4&]To@>  
this("","","",5); z)W#&JFF  
} ^tg6JB;s
 
!: EW21m  
lQ<#jxp  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) tU)r[2H2  
{ }OP%p/eY  
sSiteURL= sURL; k$0|^GL8  
sFilePath = sPath; i_9Cc$Qh<  
sFileName = sName; 9B#)h)h(=  
this.nSplitter = nSpiltter; CdzkMVH
  
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} =Qj+Ug'  
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Yn$>QS 4  
public String getSSiteURL() SD|4ybK>d  
{ }W@
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return sSiteURL; 6Y>,e;R  
} y\|-O<8O  
=hugnX<9  
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public void setSSiteURL(String value) 1fO2)$Y  
{ NDe[2  
sSiteURL = value; 5}X
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} VM<oUKh_3  
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public String getSFilePath() _ r^90  
{ n&YW".iG  
return sFilePath; FU]8.)`G  
} hk7(2j7B  
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y?Hj%,  
public void setSFilePath(String value) w8ZHk?:  
{ _Qm7x>NT4  
sFilePath = value; hyk|+z`B  
} H)j[eZP  
_>jrlIfc  
e}](6"t`5  
public String getSFileName() i3M?D}(Bs  
{ ]uStn   
return sFileName; AT%* ~tr  
} As6)_8w  
Yhc6P%{Z^  
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public void setSFileName(String value) Z0()pT  
{ ;"d,~nLn  
sFileName = value; `Ct'/h{  
} %?]{U($?  
[Hv*\rb  
nl)_`8=  
public int getNSplitter() "q9~C  
{ WIEx '{  
return nSplitter; a%MzNH  
} @O}IrC!bf  
]HJ{dcF  
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public void setNSplitter(int nCount) ;Ch+X$m9  
{ 0$xK   
nSplitter = nCount; B91S h`  
} Pp1zW3+Q  
} 1EC-e|M.  
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/* TZ&4  
**Utility.java n=<NFkeX  
*/ SZim>@R  
package NetFox; B^8ZoF  
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public class Utility { _XH4;uGg  
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public Utility() z9k*1:  
{ b"ol\&1 #  
r,`Z.A  
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} X[GIOPDx  
VZT6;1TD$8  
//线程睡眠 1&X}1  
public static void sleep(int nSecond) h.4qlx|  
{ ysSjc  
try{ 38V $<w  
Thread.sleep(nSecond); ^3Z7dIUww  
} 8N=%X-R%  
catch(Exception e) H$NP1^5!  
{ Gt^|+[gD  
e.printStackTrace (); Wphe%Of  
} ewb*?In  
} -:)DX++  
Nk lz_
]  
//日志 n~1tm  
public static void log(String sMsg) R4#;<)  
{ CTh1+&Pa  
System.err.println(sMsg); ]^iFqQe  
} |_l<JQvf`E  
XAjd %Xv<  
B,~f "  
public static void log(int sMsg) jGO9n  
{ )LkM,T  
System.err.println(sMsg); VqcBwJ!?p  
} Gkdm7SV  
} :[y]p7;{f  
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/* VKq0<+M  
**TestMethod.java $Nj'OJSj%  
*/ @+}rEe_(  
package NetFox; JfI aOhKs]  
.o-0aBG  
qg^(w fI  
public class TestMethod { @MNl*~'$.[  
[MV`pF)x  
ry$tK"v/  
public TestMethod() *hv=~A $q  
{ ///xx/weblogic60b2_win.exe 7[ZkM+z!  
try{ r/UYC"K3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); R'S c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7MKD_`g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <'r0r/0g?  
fileFetch.start(); Iv'RLM  
} NY4!TOp  
catch(Exception e){e.printStackTrace ();} j`>?"1e@x  
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} JaH* rDs-  
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public static void main(String[] args) Kg4QT/0VA  
{ zt7_r`#z  
new TestMethod(); ]
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} x7vq?fP0n  
} XxmJP5  
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