http断点续传简单实现（java)

/* JL4E`  
**SiteFileFetch.java ,iYhD-"'  
*/ WA2NjxYz  
package NetFox; *DIY;)K  
import java.io.*; 1Z ~C3)T=  
import java.net.*; |9XoRGgXU  
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public class SiteFileFetch extends Thread { 3:xx:Jt  
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SiteInfoBean siteInfoBean = null; //文件信息Bean lF64g  
long[] nStartPos; //开始位置 Ub f5:  
long[] nEndPos; //结束位置 odca?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }&+,y<>   
long nFileLength; //文件长度 #C }+  
boolean bFirst = true; //是否第一次取文件 dBA&NW07  
boolean bStop = false; //停止标志 w/ ~\NI  
File tmpFile; //文件下载的临时信息 Q4 &P\V  
DataOutputStream output; //输出到文件的输出流 >"IG\//I  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） y@v)kN)Y9\  
public SiteFileFetch(SiteInfoBean bean) throws IOException w tGS"L  
{ Fc[vs5
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siteInfoBean = bean; 517"x@6Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >}f!. i  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dH5*%  
if(tmpFile.exists ()) oJNQdW[  
{ YGPb8!  
bFirst = false; rAtCG1Vr  
read_nPos(); ?8kFAf~  
} ?J
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else 9=$pV==  
{ JtY$AP$  
nStartPos = new long[bean.getNSplitter()]; sg-^ oy*^  
nEndPos = new long[bean.getNSplitter()]; /-!Fr:Ox>  
}
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*=B<S/0  
} e.L&A|  
4
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public void run() }l+_KA  
{ |LJv*  
//获得文件长度 @TW:6v`  
//分割文件 v&G9HiH  
//实例FileSplitterFetch ,&3+w~Ua  
//启动FileSplitterFetch线程 Y(`Bc8h  
//等待子线程返回 *YH!L{y  
try{ l'[;q '  
if(bFirst) cQLPgE0  
{ ~pp< T  
nFileLength = getFileSize(); q&[G^9  
if(nFileLength == -1) i[LnU#+  
{ ~M* UMF^  
System.err.println("File Length is not known!"); }R}M>^(R4  
} L"vk ^>E6  
else if(nFileLength == -2) KM)MUPr  
{ IAkQR0fcN  
System.err.println("File is not access!"); ~sn3_6{  
} [u*7( 4e  
else #t1? *4.p  
{ jtfC3E,U  
for(int i=0;i<nStartPos.length;i++) ~0024B[G  
{ :(OV{ u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); xcl;~"c*  
} nm\f$K>Pg  
for(int i=0;i<nEndPos.length-1;i++) ?>ZrdfTwz,  
{ C$q-WoTM(  
nEndPos = nStartPos[i+1]; c]VK%zl  
} Ow1+zltgj-  
nEndPos[nEndPos.length-1] = nFileLength; .$d:c61X  
} :T PG~`k(  
} %r6_['T  
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//启动子线程 %#4;'\'5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G,Yctv  
for(int i=0;i<nStartPos.length;i++) B^/Cx  
{ _}\KC+n8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HW_2!t_R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |9 *$6Y  
nStartPos,nEndPos,i); wrCV&2CG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bZK`]L[   
fileSplitterFetch.start(); GRL42xp'*D  
} xzMpTZQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $hk_v~zM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); nf_(_O=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", LM"b%  
nEndPos = " + nFileLength); N8r+Q
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// fileSplitterFetch[nPos.length-1].start(); "lA$;\&  
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//等待子线程结束 
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//int count = 0; e6gj'GmY  
//是否结束while循环 -jTK3&5  
boolean breakWhile = false; @*T8>  
w+%p4VkA<r  
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while(!bStop) f
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{ E9 #o0Di  
write_nPos(); .$G^c  
Utility.sleep(500); blbzh';0}  
breakWhile = true; /oM&29 jy  
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for(int i=0;i<nStartPos.length;i++) X~; *zYd5  
{ lQ.3_{"s  
if(!fileSplitterFetch.bDownOver) 7BA9zs392  
{ OJcI0(G  
breakWhile = false; V3pn@'pr  
break; Zq}Cl'f  
} +w3k_^X9c  
} =)6|lz^  
if(breakWhile) C\[g>_J  
break; }<P%W~  
s.}:!fBk  
!%C&hH\  
//count++; 9VTE?,  
//if(count>4) ##NowO  
// siteStop(); E"H>[E  
} @2$iFZq~  
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System.err.println("文件下载结束！"); V:
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} 5HbPS%^.  
catch(Exception e){e.printStackTrace ();} Vuo 8[h>  
} {[B`q  
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//获得文件长度 }"c
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public long getFileSize() F a'2i<  
{ w.0]>/C  
int nFileLength = -1; h5#V,$  
try{ le`_  
URL url = new URL(siteInfoBean.getSSiteURL()); gI~jf- w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G9\@&=  
httpConnection.setRequestProperty("User-Agent","NetFox"); lhV'Q]s@6  
.7GAGMNS  
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int responseCode=httpConnection.getResponseCode(); _9zydtw  
if(responseCode>=400) u%Yr&u  
{ qg@Wzs7c~  
processErrorCode(responseCode); )%5T*}j  
return -2; //-2 represent access is error s*pgR=dZZ  
} h|'T'l&z  
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#6<9FY#  
String sHeader; ]hkway  
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for(int i=1;;i++) M%2F7 FY  
{ !23#Bz7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]LhNP}c  
//Utility.log(in.readLine()); nMHs5'_y  
sHeader=httpConnection.getHeaderFieldKey(i); Y;'7Ek)  
if(sHeader!=null) U8KEg)Msk  
{ k/#& ]8(  
if(sHeader.equals("Content-Length")) ~m56t5+uw  
{ U= PG0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f[/E $r99J  
break; ;0VE*  
} ;2;Kq)j_=  
} M-df Gk  
else \/9uS.Kw  
break; 29#;;n}p  
} daZY;_{"o  
} 7Jm9,4]  
catch(IOException e){e.printStackTrace ();} lLT;V2=osX  
catch(Exception e){e.printStackTrace ();}  :RW0<  
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Utility.log(nFileLength); B/Lx,

 
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return nFileLength; J,E'F!{  
} &6E^<v?]  
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//保存下载信息（文件指针位置） |!)3[<.  
private void write_nPos() g9;}?h  
{ }_L@CpG  
try{ v:<UbuJw  
output = new DataOutputStream(new FileOutputStream(tmpFile)); KPUc+`cN%  
output.writeInt(nStartPos.length); &k?Mt#J  
for(int i=0;i<nStartPos.length;i++) (6G5UwSt  
{ RCq_FY  
// output.writeLong(nPos); KutR l$,
 
output.writeLong(fileSplitterFetch.nStartPos); ;Q2p~-0Q  
output.writeLong(fileSplitterFetch.nEndPos); wYS,|=y  
} QO)Q%K,  
output.close(); 16YJQ ue  
} &Fl^&&1C  
catch(IOException e){e.printStackTrace ();} zTP3JOe(  
catch(Exception e){e.printStackTrace ();} l 49)Cv/  
} 4y+]V~p  
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//读取保存的下载信息（文件指针位置） c;ELAns>  
private void read_nPos() y?M99Vo4?  
{ Q<r O5 -K  
try{ d7u"Z5t  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =1%3". "n@  
int nCount = input.readInt(); 8KW}XG  
nStartPos = new long[nCount]; %?C{0(Z{  
nEndPos = new long[nCount]; gR(*lXm5w  
for(int i=0;i<nStartPos.length;i++) Sj}@5 X6 C  
{ y^:g"|q  
nStartPos = input.readLong(); >'8.>f  
nEndPos = input.readLong(); 1DGVAIcD  
} ~/hP6*  
input.close(); -X Bh\w  
} 7k:}9M~  
catch(IOException e){e.printStackTrace ();} ?PSm) ~Oa  
catch(Exception e){e.printStackTrace ();} rBkf@  
} Q4Q*5>  
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private void processErrorCode(int nErrorCode) ^[8e|,U  
{ ^owEB%  
System.err.println("Error Code : " + nErrorCode); X{ZBS^M  
} >GgX-SZ%  
r 06}@7  
)D@1V=9,  
//停止文件下载 BJk\p.BVN  
public void siteStop() 6A/Nlk.  
{ Zcz)FP#  
bStop = true; ^gh/$my;  
for(int i=0;i<nStartPos.length;i++) [cru+c+O:  
fileSplitterFetch.splitterStop(); 4fZ$&)0&  
;vF8V`f  
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} }O@S;[v S  
} wr8n*Du  
//负责部分文件的抓取 %dS7u$Rnh  
**FileSplitterFetch.java (ZjIwA9>  
*/ ?G
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package NetFox; 3b{8c8N^  
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import java.io.*; klKAwCQ,  
import java.net.*; /%rbXrR4w  
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public class FileSplitterFetch extends Thread { P
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lyIstfRh15  
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String sURL; //File URL McxJ C<  
long nStartPos; //File Snippet Start Position 23y7l=.b/  
long nEndPos; //File Snippet End Position :4<+)r26  
int nThreadID; //Thread's ID nV McHN   
boolean bDownOver = false; //Downing is over Q{H88g^=J  
boolean bStop = false; //Stop identical Cr4shdN34  
FileAccessI fileAccessI = null; //File Access interface }`IN5NdYp  
c$?qN&X_K  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Nt&}T  
{ R/b)hP~  
this.sURL = sURL; FI*.2rdSR  
this.nStartPos = nStart; \"_;rJ{!aE  
this.nEndPos = nEnd; 5cxA,T  
nThreadID = id; } ~=53$+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \Q*3/_}G  
} ]BP/KCjAI<  
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public void run() Rh9>iA@fd  
{ 5 &-fX:/  
while(nStartPos < nEndPos && !bStop) )(\5Wk9(  
{ \@['V   
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try{ `\q4z-<-  
URL url = new URL(sURL); j"_V+)SD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p."pI Bd  
httpConnection.setRequestProperty("User-Agent","NetFox"); Zj~tUCc  
String sProperty = "bytes="+nStartPos+"-"; T {(6*^g<B  
httpConnection.setRequestProperty("RANGE",sProperty); ?O\n!
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Utility.log(sProperty); 11X-X  
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InputStream input = httpConnection.getInputStream(); -YA1Uk  
//logResponseHead(httpConnection); X LA  
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byte[] b = new byte[1024]; u~1[nH:  
int nRead; -Qiay/tlu  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) isDBNXV:  
{ )f(#Fn  
nStartPos += fileAccessI.write(b,0,nRead); Qgo0uuM  
//if(nThreadID == 1) wRnt$1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /Kw
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} uzho>p[ae  
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Utility.log("Thread " + nThreadID + " is over!"); q^([ & +  
bDownOver = true; K}`.?6O  
//nPos = fileAccessI.write (b,0,nRead); kIrME:  
} ut& RKr3  
catch(Exception e){e.printStackTrace ();} +S^Uw'L$=T  
} a`q">T%q  
} cEve70MV  
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//打印回应的头信息 :~zK0v"  
public void logResponseHead(HttpURLConnection con) 9i yNR!  
{ d@7 ]=P:  
for(int i=1;;i++) Gow_
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{ *vCJTz  
String header=con.getHeaderFieldKey(i); Xy_+L_h^  
if(header!=null) *;Hvx32I  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7$Bq.Lc#z  
Utility.log(header+" : "+con.getHeaderField(header)); ="d}:Jl  
else `cy_@Z5A  
break; +7^%fX;3pW  
} =MB[v/M59w  
} mAk)9`f/  
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public void splitterStop() |M)'@s:  
{ ;5PXPpJ  
bStop = true; xo6-Y=c8  
} ,K+K`"Oy  
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} #If}P$!  
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/* la</I
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**FileAccess.java 9,`WQ+OI  
*//文件访问(定位，写) %%G2w63M  
package NetFox; A%k@75V@  
import java.io.*; l<(
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2%. A{!  
ht!o_0{~  
public class FileAccessI implements Serializable{ }_@*,  
//3iai  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 t}c ymX
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RandomAccessFile oSavedFile; VI74{='=  
long nPos; Al5E  
:+bQ
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public FileAccessI() throws IOException #i%it  
{ ?y>P  
this("",0); -iR}kP|  
} ; "ux{ .  
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public FileAccessI(String sName,long nPos) throws IOException =$X5O&E3'  
{ Dwj!B;AZ_  
oSavedFile = new RandomAccessFile(sName,"rw"); Xjw>Qws  
this.nPos = nPos; dPc*!xrq  
oSavedFile.seek(nPos); ]e$mTRi*  
} )iNMjg  
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public synchronized int write(byte[] b,int nStart,int nLen) |F=!0Id<  
{ 8`v+
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int n = -1; E/v.+m  
try{ 64%P}On  
oSavedFile.write(b,nStart,nLen); aHNR0L3$}{  
n = nLen; ]>tYU   
} 0M7Or)qN  
catch(IOException e) $5yH(Z[[
 
{ )e
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e.printStackTrace (); H!
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} x4r8^,K3Zn  
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return n; Se.\wkl#Y  
} #k&"Rv;,  
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i ?&t@"'  
} twv|,kM  
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/* 5%BexIk  
**SiteInfoBean.java [fx1H~T<  
*/ }TY}sr  
package NetFox; ,pM~Phmp  
J -tOO  
7I
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public class SiteInfoBean { NRN3*YGo  
d[E~}Dq3#  
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private String sSiteURL; //Site's URL /j/,@,lw7z  
private String sFilePath; //Saved File's Path )9I>y2WU~  
private String sFileName; //Saved File's Name I@Pp[AyG  
private int nSplitter; //Count of Splited Downloading File ;\ ^'}S|3Z  
}(k#,&Fv`  
3#N'nhUzA  
public SiteInfoBean() t5t,(^;f  
{//nSplitter的缺省值为5 RfH.WXi  
//default value of nSplitter is 5 %:2EoXN"  
this("","","",5); cq lA"Eof  
} POvxZU  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <7'`N\a  
{ Tzr_K  
sSiteURL= sURL; ~tK4C|  
sFilePath = sPath; rPhx^ QKH2  
sFileName = sName; PD #9Z=Hj  
this.nSplitter = nSpiltter; Dl=9<:6FW  
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} er@"4R0  
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< z':_,  
public String getSSiteURL() `9;0Y  
{  N>ncv  
return sSiteURL; w>#{Nl7gz  
} ]oT8H?%*Y  
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public void setSSiteURL(String value) MWdev.m:Z  
{ (LiS9|J!  
sSiteURL = value; p7{2/mj  
} I0iTa99K  

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public String getSFilePath() 8;PS>9<  
{ Bd'X~Vj<  
return sFilePath; Vu`5/QDq  
} =K)[3mXX  
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5hHLC7tT9  
public void setSFilePath(String value) 3ey.r%n  
{ cL<,]%SkE  
sFilePath = value; X }`
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} RWRqu }a  
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public String getSFileName() b^
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{ YQ@2p?4m  
return sFileName; h<Ct[46,S  
} ? 'qyI^m@  
v
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public void setSFileName(String value) 3RX9LJGX  
{ 0h~{K  
sFileName = value; (q0vql  
} M&jlUr&l  
{!j)j6(NY
 
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public int getNSplitter() Q lA?dXQ  
{ >gs_Bzy]  
return nSplitter; j74hWz+p4  
} BsA'r+ho?H  
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public void setNSplitter(int nCount) k0O5c[j  
{ a??8)=0|}  
nSplitter = nCount; \K~wsu/?`  
} 1og+(m`BL  
} G&Dl($  
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)`(]jx!  
/* !4cY^4>o  
**Utility.java ^[r1Dk  
*/ ;gZ/i93:Q  
package NetFox; GB^`A  
W;cYg.W2  
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public class Utility { F81EZ/  
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public Utility() czU"  
{ :b(W&iBWhI  
Z)$@1Q4P?1  
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} uSRhIKy  
b=xn(HE8|  
//线程睡眠 9(q(;|;Hp  
public static void sleep(int nSecond) ZAU#^bEQB  
{ PZJ9f8V  
try{ K)wWqC.  
Thread.sleep(nSecond); >;hAw!|#  
} &mmaoWR  
catch(Exception e)
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{ OR!W3 @  
e.printStackTrace (); e2NK7  
} \.O&-oi  
} w(aHB8T  
~=iH*AQR  
//日志 ;aWk-  
public static void log(String sMsg) %+Ze$c}X  
{ :o{,F7(P  
System.err.println(sMsg); Gj-nTN  
} e%L[bGW'  
;*<R~HJt  
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public static void log(int sMsg) 'UWkJ2:!  
{ {9}CU~R  
System.err.println(sMsg); '!`\!=j-`  
} (^y"'B  
} eBnx$  
&=jPt%7#M  
;J TY#)Bh  
/* bI|G %  
**TestMethod.java !pw)sO~  
*/ &`v?oN9$  
package NetFox; UAhWJ$(C  
kl.;E{PL  
;]Q6K9.d8  
public class TestMethod { bV&9>fC  
CAC4A
  
3MNM<Ih  
public TestMethod() "W%YsN0  
{ ///xx/weblogic60b2_win.exe A| A
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try{ C&H'?0Y@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J'|=J   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,7Hyrx`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4 O8ct,Y  
fileFetch.start(); zU~ Ff"<  
} ,GYQ,9:  
catch(Exception e){e.printStackTrace ();} i83
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M
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} d7vPZ_j^z  
}-Mg&~e`  
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public static void main(String[] args) Zyz#xMmM  
{ "Esl I  
new TestMethod(); `/>kN%  
} M@.S Q@E  
} jjj<B
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