http断点续传简单实现（java)

/* <FY&h#  
**SiteFileFetch.java Ia2(Km  
*/ ) Qq'Wp3i  
package NetFox; rH&G<o&,  
import java.io.*; V/PAi.GZ  
import java.net.*; $;2)s}ci  
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public class SiteFileFetch extends Thread { 1,,|MW  
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SiteInfoBean siteInfoBean = null; //文件信息Bean =m7H)z)i*J  
long[] nStartPos; //开始位置 0GZq`a7[  
long[] nEndPos; //结束位置 o#>a 5  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4KXc~eF[M"  
long nFileLength; //文件长度 $5AC1g'  
boolean bFirst = true; //是否第一次取文件 [4*1}}gW%5  
boolean bStop = false; //停止标志 Qzqc .T  
File tmpFile; //文件下载的临时信息 s)zJT  
DataOutputStream output; //输出到文件的输出流 =E(#YCx  
2*[QZ9U[@  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） w{!(r  
public SiteFileFetch(SiteInfoBean bean) throws IOException lCJ6Ur;  
{ A%u_&a}  
siteInfoBean = bean; b9~A-Z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9sSN<7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 48O~Jx,  
if(tmpFile.exists ()) ,zhJY ?sk  
{ yb2}_k.JG  
bFirst = false; ZF6c{~D  
read_nPos(); LY 0]l$  
} k?*KnfVh!  
else P
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{ UMU2^$\iS  
nStartPos = new long[bean.getNSplitter()]; ?>$l  
nEndPos = new long[bean.getNSplitter()]; =Mj0:rW  
} 7I9aG.;  
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} u5B:^.:p  
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public void run() w(9*7pp  
{ ;=4Xz\2  
//获得文件长度 /
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//分割文件 u JY)4T  
//实例FileSplitterFetch >6<q8{*  
//启动FileSplitterFetch线程 jQ\zGJ3  
//等待子线程返回 "ZrOrdlg+A  
try{ 0.TaXb
i  
if(bFirst) 5]5 KB;  
{ "%qzj93>  
nFileLength = getFileSize(); :|+Qe e  
if(nFileLength == -1) Qm4o7x{q  
{ [P~hjm
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System.err.println("File Length is not known!"); CyDV r  
} &V7M}@  
else if(nFileLength == -2) A\fb<  
{ l12{fpm  
System.err.println("File is not access!"); - e"jw#B  
} >w+HHs/$wK  
else :,B7-kBw  
{ k{;,6H  
for(int i=0;i<nStartPos.length;i++) 83%)/_&  
{ 6$\jAd|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?e[lr>-  
} QnQOm""  
for(int i=0;i<nEndPos.length-1;i++) 8[vc?+>&  
{ c;?fMX  
nEndPos = nStartPos[i+1]; +N`ua  
} z2_6??tS/c  
nEndPos[nEndPos.length-1] = nFileLength; Fz#X=gmG  
} ':{>a28=  
} Ae]sGU|?'  
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//启动子线程 ,#MCn  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -Eu6U`"(  
for(int i=0;i<nStartPos.length;i++) >zAUW[]C:I  
{ mKrh[nA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ktIi$v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %\]*OZ7  
nStartPos,nEndPos,i); *Kdda} J+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (e(:P~Ry  
fileSplitterFetch.start(); !?c|XdjZ  
} YIw1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'AN>`\mR$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1-lu\"H`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", cufH?Xg<  
nEndPos = " + nFileLength); 2hzsKkrA {  
// fileSplitterFetch[nPos.length-1].start(); ,) J~,^f6  
y=?)n\f  
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//等待子线程结束 i3rH'B-I.  
//int count = 0; hjZKUMG(k  
//是否结束while循环 8Z(Mvq]f&  
boolean breakWhile = false; *S2ypzwRZ,  
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while(!bStop) 0PlO(",a  
{ JvY
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write_nPos(); j~!X;PV3  
Utility.sleep(500); |JQQU!x  
breakWhile = true; ;q*e=[_DF  
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for(int i=0;i<nStartPos.length;i++) I:mr}mv=i  
{ vM5k_D  
if(!fileSplitterFetch.bDownOver) B)0i:"q  
{ nDHTV!]<  
breakWhile = false; zAiXo
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break; [eC2"&}  
} V#iPj'*   
} *s:(j
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if(breakWhile) xL\0B,]  
break; 3f,hw5R  
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//count++; RS8Hf~0G  
//if(count>4) !O<)\)|g  
// siteStop(); N<XNTf  
} ,^2>k3=  
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System.err.println("文件下载结束！"); / G7vwC  
} :51/29}  
catch(Exception e){e.printStackTrace ();} R}!:'^  
} -w"VK|SGm  
,^\2P$rT  
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//获得文件长度 7t0er'VC  
public long getFileSize() ;EP:
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{ QC}CRkp  
int nFileLength = -1; ,Ge
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try{ 5Ou`z5S\k  
URL url = new URL(siteInfoBean.getSSiteURL()); -#N.X_F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8~@c)Z;  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^f4s"T  
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int responseCode=httpConnection.getResponseCode(); Ju1D =b  
if(responseCode>=400)
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{ qKr8)}h  
processErrorCode(responseCode); Q7jb'y$ozO  
return -2; //-2 represent access is error Dv5D~on{  
} l~w2B>i)  
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String sHeader; Y[}>CYO  
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for(int i=1;;i++)  KY$)#i  
{ "Q@ronP(~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o$jLzE"  
//Utility.log(in.readLine()); Y)*#)f  
sHeader=httpConnection.getHeaderFieldKey(i); O;:mCt _H  
if(sHeader!=null) \fz<.l]  
{ d928~y W  
if(sHeader.equals("Content-Length")) Q ayPo]O  
{ R;&AijS8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); hKL4cpK4  
break; &^}1O:8e  
} DgId_\Ze  
} 9
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else e>+i>/Fn{h  
break; cQy2"vtU  
} Lt?lv2k=L  
} vW
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catch(IOException e){e.printStackTrace ();} SJb&m-  
catch(Exception e){e.printStackTrace ();} I_}SB|  
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Utility.log(nFileLength); vdivq^%=a  
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return nFileLength; wh$sn
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} !/'t5~x[  
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//保存下载信息（文件指针位置） QwW&\h[8?  
private void write_nPos() bh,[ 3X%  
{ :~&~y-14  
try{ ^ Edfv5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5sj4
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output.writeInt(nStartPos.length); 36}?dRw#p  
for(int i=0;i<nStartPos.length;i++) Yb|
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{ 'N (:@]4N  
// output.writeLong(nPos); PxWT1 !  
output.writeLong(fileSplitterFetch.nStartPos); KKja/p  
output.writeLong(fileSplitterFetch.nEndPos); (y=C_wvqZ  
} HJ=
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output.close(); k+# %DK  
} > kGGR  
catch(IOException e){e.printStackTrace ();} T"{>t  
catch(Exception e){e.printStackTrace ();} #^u$  
} Yg]-wQrH  
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//读取保存的下载信息（文件指针位置） u@W|gLT1  
private void read_nPos() Z3"%`*Tmq-  
{ 1F5XvQl  
try{ orzZ{8
7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5;tD"/nz  
int nCount = input.readInt(); >N^Jj:~l  
nStartPos = new long[nCount]; <GS^  
nEndPos = new long[nCount]; 7Haa;2 T'  
for(int i=0;i<nStartPos.length;i++) ?ZV/U!y  
{ I&D5;8  
nStartPos = input.readLong(); 8bTn^!1  
nEndPos = input.readLong(); ?&8^&brwG  
} <T` 7%$/E  
input.close(); @E&J_un  
} *>Ns_su7W  
catch(IOException e){e.printStackTrace ();} NO*u9YH?  
catch(Exception e){e.printStackTrace ();} j$M h+5  
} QyEnpZ8?a  
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private void processErrorCode(int nErrorCode) du<tGsy  
{ h9t$Uz^N  
System.err.println("Error Code : " + nErrorCode); Lu?C-$a C  
} Vh'P&W?[  
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}n]
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//停止文件下载 l.q&D<
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public void siteStop() >nJ\BPx  
{ {DV_*
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bStop = true; 8r*E-akuyr  
for(int i=0;i<nStartPos.length;i++) P{8iJ`rBG  
fileSplitterFetch.splitterStop(); Y@;CF  
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} .<->C?#  
} /j#n  
//负责部分文件的抓取 ux=w!y;}  
**FileSplitterFetch.java JB%',J  
*/ vDp8__^  
package NetFox; d2*fLEsF  
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import java.io.*; GoJ.&aH $  
import java.net.*; )MtF23k)g  
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public class FileSplitterFetch extends Thread { _'#n6^Us<  
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String sURL; //File URL  'K$[^V  
long nStartPos; //File Snippet Start Position K%,2=.  
long nEndPos; //File Snippet End Position 3(="YbZ  
int nThreadID; //Thread's ID ;0Q4<F  
boolean bDownOver = false; //Downing is over 1XrO~W\=  
boolean bStop = false; //Stop identical `"Jj1O@  
FileAccessI fileAccessI = null; //File Access interface JYMiLph<  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6O7'!@@  
{ WltQ63u  
this.sURL = sURL; h}>"j%I  
this.nStartPos = nStart; ]{sU&GqBLe  
this.nEndPos = nEnd; 7!$Q;A  
nThreadID = id; Wvq27YK'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )Oq|amvC  
} Z]A{ d[  
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public void run() J-[,KME_^  
{ IDad9 Bx  
while(nStartPos < nEndPos && !bStop) MS nG3]{z  
{ gI&#o@Pm  
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try{ y|jl[pyg)  
URL url = new URL(sURL); 5^}\4.eXo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b10cuy|a/X  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,bZL C  
String sProperty = "bytes="+nStartPos+"-"; U2ohHJ``  
httpConnection.setRequestProperty("RANGE",sProperty); UBv
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Utility.log(sProperty); 1Rt33\1J0  
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InputStream input = httpConnection.getInputStream(); l94b^W}1)W  
//logResponseHead(httpConnection); v>6"j1Z  
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byte[] b = new byte[1024]; ]N/=Dd+|  
int nRead; bc7/V#W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >d(~#Z`  
{ ]dF ,:8  
nStartPos += fileAccessI.write(b,0,nRead); zU,9T  
//if(nThreadID == 1) .zr-:L5{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); # ncRb  
} UI0(=>L  
|+{)_?  
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Utility.log("Thread " + nThreadID + " is over!"); Vk`h2BV  
bDownOver = true; b k~(^!R  
//nPos = fileAccessI.write (b,0,nRead); af6M,{F  
} a
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catch(Exception e){e.printStackTrace ();} 2_)\a(.Qu  
} Ah1]Y}sy  
} n"$jG:AQJ  
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u:}%xD6  
//打印回应的头信息 36.Z0Z1'F>  
public void logResponseHead(HttpURLConnection con) Dxtp2wu%t  
{ HUcq%.  
for(int i=1;;i++) .4S.>~^7  
{ 1&\0:vA^Y  
String header=con.getHeaderFieldKey(i); O],T,Z?z  
if(header!=null) V[mT<Lc  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); k3~}7]O)  
Utility.log(header+" : "+con.getHeaderField(header)); 3\AU 72-  
else $5>e  
break; 8bxfj<O,  
} QemyCCP+  
} >3ZFzh&OYQ  
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}#3V+X  
public void splitterStop() '|ad_M  
{ !H#bJTXB  
bStop = true; W'els)WJ|x  
} 84$nT>c  
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} Y=%tn8<  
1f%1*L0>@  
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/* N%kt3vmQ_  
**FileAccess.java %) /s;Q,  
*//文件访问(定位，写) `CBZhI%%  
package NetFox; dA#Q}.*r  
import java.io.*; ^/uA?h:]\  
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public class FileAccessI implements Serializable{ 1Rq,
a  
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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 i3dkYevs?  
RandomAccessFile oSavedFile; F7A=GF'  
long nPos; ^"2i   
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public FileAccessI() throws IOException EH$1fvE  
{ au N6prGe  
this("",0); UG'Q]S#!  
} YA''2Ii  
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public FileAccessI(String sName,long nPos) throws IOException NYt&@Z}]  
{ .
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oSavedFile = new RandomAccessFile(sName,"rw"); `V=N*hv`  
this.nPos = nPos; !-ok"k0,u  
oSavedFile.seek(nPos); I+BHstF5um  
} UGD2  
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hM@ HA  
public synchronized int write(byte[] b,int nStart,int nLen) >x/z7v?^I  
{ \O}E7-  
int n = -1; nv GF2(;l  
try{ J cPtwa;q@  
oSavedFile.write(b,nStart,nLen); ztnFhJ<a$  
n = nLen; 2K< 8  
} d^Inb!%w  
catch(IOException e) _+p4Wvu~0  
{ 
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e.printStackTrace (); N|1M1EBOu>  
} $()5VMb  
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 RwKdxK+;  
return n; o%v0h~tn  
} kr+D,h01  
{,3>"  
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} ^]7}YF2|  
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/* 7"aN#;&  
**SiteInfoBean.java Hcl(3>Jn2  
*/ A$<.a
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package NetFox; y6LWx:  
LISMngQ.  
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public class SiteInfoBean { t5[#x4 p  
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private String sSiteURL; //Site's URL TX$r`~  
private String sFilePath; //Saved File's Path Gnf~u[T6  
private String sFileName; //Saved File's Name ~kShq%  
private int nSplitter; //Count of Splited Downloading File IHe/xQ@  
4^TG>j?M  
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public SiteInfoBean() OTy.VT|  
{//nSplitter的缺省值为5 [p{#XwN  
//default value of nSplitter is 5 pv*,gSS  
this("","","",5); J!0DR4=Xi  
} hakKs.U|[  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {aY%gk?y#>  
{ 9 TvV=  
sSiteURL= sURL; "^4_@ oo  
sFilePath = sPath; k,'L}SK  
sFileName = sName; A9f)tqbc  
this.nSplitter = nSpiltter; ZNf6;%oGG  
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|kw)KEi}H  
}  `dFq:8v  
\Z]UA&v_  
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public String getSSiteURL() (&}i`}v_  
{ =4[v3Qx  
return sSiteURL; aa?w:3  
} |zR8rqBX;  
/a^1_q-bX  
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public void setSSiteURL(String value) bLe<G  
{ 33#0J$j7  
sSiteURL = value; e<
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} 'SCidN(n  
]vgB4~4#LP  
nN*
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public String getSFilePath() :,Pn3xl
 
{ VTG9$rQZ  
return sFilePath; yHs-h   
} 8S%52W|  
f
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public void setSFilePath(String value) ux_Mr
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{ dik:4;  
sFilePath = value; >}!mQpAO  
} 7bk%mQk  
29!q!g|  
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public String getSFileName() @c<3b2  
{ c/zJv*}x?  
return sFileName; 'f[T&o&L/  
} Ys@}3\Mc  
: y5<go8e  
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public void setSFileName(String value) 1jy9lP=  
{ ^zt-HDBR_  
sFileName = value; m\$\ 09  
} .Jt[(;  
R$[#+X!  
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public int getNSplitter() Z7_m)@%;kk  
{ W0epAGrB  
return nSplitter; 0BH_'ZW  
} bty/  
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public void setNSplitter(int nCount) :lB=Lr)  
{ ZJwrLV  
nSplitter = nCount; .2>p3|F  
} } p&&_?  
} ]@uE#a:[  
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/* q)Fq i  
**Utility.java u>TZt]h8  
*/ 4$*%gL;f^  
package NetFox; +m8!U=Zi  
{_S}H1,  
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public class Utility { 'Y56+P\u  
1jc, Y.mP  
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public Utility() M@?xa/E64  
{ >2,Gy-&"0  
&|!7Z4N  
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} GDD '[;  
Y7vA`kjD-C  
//线程睡眠 Q($Z%1S  
public static void sleep(int nSecond) J2j U4mR  
{ G3rj`Sg^c  
try{ P#fM:z@[  
Thread.sleep(nSecond); |b-]n"}c>  
} J41G&$j(  
catch(Exception e) |7X:TfJ  
{ QF&W`c  
e.printStackTrace (); ]p;FZ4-T  
} f|R"uW +  
}  b^p"|L  
#{=;NuP  
//日志 ^_
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public static void log(String sMsg) #/I[Jqf  
{ Sr%;fq  
System.err.println(sMsg); >2< 8kBF_  
} * 1Od-3  
~i21%$  
 8HRmQ  
public static void log(int sMsg) (s{RnD  
{ Oi:<~E[kz.  
System.err.println(sMsg); j%y$_9a7  
} KyzFnVH3)  
} ' 4ER00  
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/* dlG=Vq&Y  
**TestMethod.java 2^)1N>"g  
*/ ZKXo-~=>  
package NetFox;
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;\[(- )f!=  
!vk|<P1  
public class TestMethod { kWNV%RlSx  
'&sE=.  
8P"_#M?!  
public TestMethod() MdXchO-Lyc  
{ ///xx/weblogic60b2_win.exe v$=QA:!U  
try{ M4d47<'*~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IXb}AxBf  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z*])6=2Q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); sYdRh?Hq  
fileFetch.start(); V13BB44  
} Vur bW=~g  
catch(Exception e){e.printStackTrace ();} =i(?deR  
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} TO-nD>  
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public static void main(String[] args) Uz7^1.-g4  
{ )LdyC`S\c  
new TestMethod(); fd#jY}  
} '}rRzD:  
} nN~~cV  
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