http断点续传简单实现（java)

/* e-=PT1T`  
**SiteFileFetch.java Vn;]''_  
*/ ]3jH^7[?  
package NetFox; I;:_25WGC  
import java.io.*; f(o`=% k8  
import java.net.*; K):sq{  
l #z`4<  
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public class SiteFileFetch extends Thread { 9GaER+d|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %y+j~]^:  
long[] nStartPos; //开始位置 PQ]N>'v-  
long[] nEndPos; //结束位置 4FdH:os  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7gaC)j&  
long nFileLength; //文件长度 |XG7
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boolean bFirst = true; //是否第一次取文件 {z_pL^S'52  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 yo6IY  
DataOutputStream output; //输出到文件的输出流 ;0q6 bp(<H  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (@
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public SiteFileFetch(SiteInfoBean bean) throws IOException $,42h  
{ _lqAxWH
  
siteInfoBean = bean; x%&V!L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); o!S_j^p[C  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \vQ (  
if(tmpFile.exists ()) <qx-%6  
{ DR8dJ#  
bFirst = false; M!'tD!NWc  
read_nPos(); >UH=]$0N  
} Fj4:_(%nG  
else ,Z"sh*  
{ H/f= 2b  
nStartPos = new long[bean.getNSplitter()]; -E"o)1Pj6C  
nEndPos = new long[bean.getNSplitter()]; ~VF,qspO  
} ~'iuh>O)  
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} `#F>?g$2  
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public void run() '?
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{ enM 3  
//获得文件长度 ppA8c6  
//分割文件 (fS4qz:&l  
//实例FileSplitterFetch 0nAS4Az  
//启动FileSplitterFetch线程 >T
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//等待子线程返回 ERplDSfO-  
try{ 3kg+*]tLx  
if(bFirst) 3{z }[@N  
{ 3:S"!F  
nFileLength = getFileSize(); []NAV  
if(nFileLength == -1) &#.&xc2sRZ  
{ i
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System.err.println("File Length is not known!"); S1JB]\  
} V qf}(3K0  
else if(nFileLength == -2) r@aFB@  
{ Sob+l'U$  
System.err.println("File is not access!"); ZN^Q!v  
} RIlPH~  
else ~ nIZg5  
{ '_8Vay~  
for(int i=0;i<nStartPos.length;i++) pQD8#y)`C  
{ j*nCIxF  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &Jz%L^  
} SBA;p7^"  
for(int i=0;i<nEndPos.length-1;i++) O;r8l+  
{ dc*#?G6^  
nEndPos = nStartPos[i+1]; 42~;/4  
} F6Ixu_s  
nEndPos[nEndPos.length-1] = nFileLength; }v{F9dv  
} l6RJour  
} Z(FAQ\7  
@: NrC76  
|<S9nZg%p  
//启动子线程 uG<+IT|x  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
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for(int i=0;i<nStartPos.length;i++) ' x|B'  
{ RV~w+%f  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U i;o/Z3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7~ 2X/  
nStartPos,nEndPos,i); |Ia46YS  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SU1,+7"  
fileSplitterFetch.start(); h^4oy^9  
} k0,~wn\#h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sfH|sp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !#3R<bW`R8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?tOzhrv  
nEndPos = " + nFileLength); Jyn>:Yq
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// fileSplitterFetch[nPos.length-1].start(); _g
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//等待子线程结束 t+pI<c^]y  
//int count = 0; YEGXhn5E  
//是否结束while循环 ,]+6kf5  
boolean breakWhile = false; jtA Yp3M-$  
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while(!bStop) _)ERi*}x8  
{ om(#P5cSM;  
write_nPos(); 3Z`oI#-x  
Utility.sleep(500); *l|CrUa  
breakWhile = true; Tf+B<B:  
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for(int i=0;i<nStartPos.length;i++) 1=s%.0  
{ z19y>j
 
if(!fileSplitterFetch.bDownOver) pNDL:vMWP  
{ 4bmp
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breakWhile = false; s+4G`mq>*  
break; E*[X\70  
} ,cS|fG  
} 0L|A  
if(breakWhile) G.9?ApG9  
break; b-wFnMXk+  
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//count++; m]V5}-?al  
//if(count>4) xl s_g/Q  
// siteStop(); 98A ;R  
} gXG1w>  
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BK,=(;d3  
System.err.println("文件下载结束！"); D=e&"V a  
} 5pz%DhjLo  
catch(Exception e){e.printStackTrace ();} @>JO &,od  
} @ %kCe>r  
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//获得文件长度 R5qC;_0cV  
public long getFileSize() U$qSMkj6RK  
{ Ig]Gg/1G  
int nFileLength = -1; S=2-<R  
try{ 9"oc.ue.2D  
URL url = new URL(siteInfoBean.getSSiteURL()); OLlNCb#t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u3Ua>A-  
httpConnection.setRequestProperty("User-Agent","NetFox"); (@mvNlc:  
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we!}"'E;  
int responseCode=httpConnection.getResponseCode(); uEH&]M>d_  
if(responseCode>=400) rk{DrbRx  
{ 90&ld:97  
processErrorCode(responseCode); e!Y:UB2 7u  
return -2; //-2 represent access is error }_Jr[ia
B  
} J)6f"{} &  
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String sHeader; 7i,}F|#8  
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for(int i=1;;i++) ,vl][MhM  
{ ]HCu tq  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Jn-iIl  
//Utility.log(in.readLine()); x<4-Q6'{S  
sHeader=httpConnection.getHeaderFieldKey(i); UJ<eF/KSmG  
if(sHeader!=null) yuWoz*:t  
{ a=T_I1  
if(sHeader.equals("Content-Length")) ](vOH#E  
{ wz<
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9;NR   
break; _py%L+&{  
} 7g[T#B'/x,  
} f =B)jYI  
else iZyhj%#  
break; y".uu+hL`  
} *2Il{KOA^  
} "WV]| TS"]  
catch(IOException e){e.printStackTrace ();} i!@L`h!rw  
catch(Exception e){e.printStackTrace ();} B0T[[%~3M  
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Utility.log(nFileLength); T1.
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return nFileLength; dq?{?~3  
} HZ* <BjE:"  
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UJ3l8 %/`k  
//保存下载信息（文件指针位置） sg RY`U.C  
private void write_nPos() x >hnH{~w  
{ x'tYf^Va28  
try{ Ze[ezu  
output = new DataOutputStream(new FileOutputStream(tmpFile)); c;
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output.writeInt(nStartPos.length); %{Ez0XwGCn  
for(int i=0;i<nStartPos.length;i++) )o-rg  
{ x>THyY[sq  
// output.writeLong(nPos); ]~iOO %&R  
output.writeLong(fileSplitterFetch.nStartPos); rf?Q# KM\W  
output.writeLong(fileSplitterFetch.nEndPos); R]L|&{  
} A8Tq2]"* S  
output.close(); {B8W>>E  
} gh>'O/9  
catch(IOException e){e.printStackTrace ();} M}MXR=X,  
catch(Exception e){e.printStackTrace ();} :f<3`x'  
} 1$vs
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//读取保存的下载信息（文件指针位置） E(N?.i-%$  
private void read_nPos() ('BFy>@  
{ H.cN(7LXm  
try{ UT!gAU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hDTiXc  
int nCount = input.readInt(); 6fV%[.RR  
nStartPos = new long[nCount]; 7)aitDD  
nEndPos = new long[nCount]; 'S]7:/CI  
for(int i=0;i<nStartPos.length;i++) |>(d^<nR^v  
{ 7.@$D;L9  
nStartPos = input.readLong(); DA;,)A&=Q  
nEndPos = input.readLong(); rjqQWfShY  
} 0]%0wbY1  
input.close(); xLhN3#^m  
} =g|e-XC  
catch(IOException e){e.printStackTrace ();} ,5`pe%W7  
catch(Exception e){e.printStackTrace ();} *[K\_F?^h  
} g#b[-)Qx  
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private void processErrorCode(int nErrorCode) 0Yk@O) x  
{ aD)XxXwozm  
System.err.println("Error Code : " + nErrorCode); $h"Ht2/ J  
} CGmObN8~'F  
;{
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//停止文件下载 T4MB~5,i  
public void siteStop() Ws2SD6!4`  
{ 4JF)w;X}  
bStop = true; )\fAy  
for(int i=0;i<nStartPos.length;i++) Q(Q.(  
fileSplitterFetch.splitterStop(); L,G{ t^j  
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} : V16bRpjL  
} ukM11LD5x  
//负责部分文件的抓取 iEd%8 F h  
**FileSplitterFetch.java f%r0K6p  
*/ ACQbw)tiv}  
package NetFox; s>y=-7:N  
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import java.io.*; S-)mv'Al'F  
import java.net.*; MR8\'0]  
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public class FileSplitterFetch extends Thread { (Uk1Rt*h  
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String sURL; //File URL qm30,$\c`~  
long nStartPos; //File Snippet Start Position Qn`$xY9mT  
long nEndPos; //File Snippet End Position 8j~:p!@  
int nThreadID; //Thread's ID V/%tFd1  
boolean bDownOver = false; //Downing is over />1Ndj  
boolean bStop = false; //Stop identical "$)Nd+ny  
FileAccessI fileAccessI = null; //File Access interface Vq[L4  
N^i<A2'6S;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException o)w8 ]H/  
{ 9G)Sjn`AQ  
this.sURL = sURL; BI9~%dm  
this.nStartPos = nStart; :=J~t@  
this.nEndPos = nEnd; xDRNtLj<u  
nThreadID = id; m~KGB"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 M7D@Uj&xx(  
} (#zSVtZ  
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public void run() '2`MT-  
{ K.A!?U=
 
while(nStartPos < nEndPos && !bStop) <hG=0Zcr  
{ 2^-Z17Z}  
<sXmk{  
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try{ \etuIFQ#U  
URL url = new URL(sURL); "T>74bj_|Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AGwFD  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xy_ <Yqx}  
String sProperty = "bytes="+nStartPos+"-"; B o@B9/ABv  
httpConnection.setRequestProperty("RANGE",sProperty); NZUQ R`5  
Utility.log(sProperty); zj G>=2  
[X >sG)0S~  
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InputStream input = httpConnection.getInputStream(); ,,*i!%Adw  
//logResponseHead(httpConnection); lTNfTO^  
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byte[] b = new byte[1024]; OKDBzl  
int nRead; x --buO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [/.5{|&GSt  
{ )ESF)aKMiz  
nStartPos += fileAccessI.write(b,0,nRead); jI`1>>N&1  
//if(nThreadID == 1) g[P.lpi{U  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WM8 Ce0E  
} &<{=  
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Utility.log("Thread " + nThreadID + " is over!"); H^T
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bDownOver = true; C^uH]WO  
//nPos = fileAccessI.write (b,0,nRead); .gPE Qc+D  
} A0x"Etbw)  
catch(Exception e){e.printStackTrace ();} 8"2 Y$*)(  
} cO$ PK  
} D
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h> K~<BAz'  
//打印回应的头信息 I?sA)!8  
public void logResponseHead(HttpURLConnection con) }F=+*-SYZ  
{ + V:P-D  
for(int i=1;;i++) 3?Ckk{)&  
{ ~T<yp  
String header=con.getHeaderFieldKey(i); W}6(;tI  
if(header!=null) INQ0h`T  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); l#8SlRji  
Utility.log(header+" : "+con.getHeaderField(header)); FU-YI"  
else n[zP}YRr  
break; Fv n:V\eb  
} %vPs38Fks  
} e/@tU'$  
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public void splitterStop() OoKzPePWji  
{ Y)@mL~){  
bStop = true; S1Q2<<[  
} cU\Er{ k  
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} 7I~Ww{  
=
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/* 6< x0e;>  
**FileAccess.java Do@:|n  
*//文件访问(定位，写) !,}W|(P)  
package NetFox; 9W$d'IA  
import java.io.*; (P;z* "q  
8y;W+I(71  
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public class FileAccessI implements Serializable{ \Q.Qos  
oY@4G)5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 I8r5u=PH  
RandomAccessFile oSavedFile; (g2?&b iuz  
long nPos; 1 h(oty2p  
$YvT* T$_  
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public FileAccessI() throws IOException %AbA(F  
{ yYmV^7G  
this("",0); k|W=kt$P  
} 6 W/S?F~{  
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public FileAccessI(String sName,long nPos) throws IOException %MyA;{-F6  
{ 6x KbK1W  
oSavedFile = new RandomAccessFile(sName,"rw"); 2XJn3wPi  
this.nPos = nPos; .5+*,+-  
oSavedFile.seek(nPos); Vx_lI #3  
} |He,v/r  
9tmYrhb$  
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public synchronized int write(byte[] b,int nStart,int nLen) G5W6P7-<X  
{ *<*{gO?Q4
 
int n = -1; mIVnc`3s  
try{ a~YFJAkg9  
oSavedFile.write(b,nStart,nLen); LjUBV_J  
n = nLen; 
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} BcaMeb-Z  
catch(IOException e) +5Z0-N@  
{ UF)rBAv(/  
e.printStackTrace (); zI/)#^SQ  
} IuDg-M[  
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return n; }B2H)dG^K  
} $Gb] K{e  
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} <)y44x|S'  
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/* rDkAeX0  
**SiteInfoBean.java 4kGA`XhS*  
*/ ]T\K-;i  
package NetFox; U#G[#sd> K  
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.{D[!Dp#h  
public class SiteInfoBean { 0gPz|v>z  
(gBP`*2  
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private String sSiteURL; //Site's URL B]dHMLzl  
private String sFilePath; //Saved File's Path $Tu%dE(OF  
private String sFileName; //Saved File's Name DQW^;Ls  
private int nSplitter; //Count of Splited Downloading File kvs^*X''Ep  
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public SiteInfoBean() #M*h)/d[A  
{//nSplitter的缺省值为5 `we2zT  
//default value of nSplitter is 5 lZCvH1&"  
this("","","",5); fI}Z`*  
} dT8m$}h9  
F7J-@T<  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [oOZ6\?HB  
{ x!bFbi#!"  
sSiteURL= sURL; +U&aK dQs  
sFilePath = sPath; N;tUrdg
Q  
sFileName = sName; x<60=f[O2R  
this.nSplitter = nSpiltter; |Q:$G!/  
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} Z@&_ T3M  
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public String getSSiteURL() RL |.y~  
{ dluNA(Xc-  
return sSiteURL;  Y2vzK;  
} 9'3%%o  
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public void setSSiteURL(String value) %KNnss}  
{ .:Bjs*
 
sSiteURL = value; Z `O.JE  
} a#FkoA~M  
w=d#y )
1  
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public String getSFilePath() *MW)APw=  
{ /pgfa-<  
return sFilePath; Je2o('MA  
} @i&LKr8  
r&)/3^S '  
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public void setSFilePath(String value) Tn2Z{.q$  
{ ZgF
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sFilePath = value; 4;Z`u.1  
} _CAWD;P  
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public String getSFileName() z*ZEw  
{ Ya*lq! u  
return sFileName; jVL<7@_*  
} r4dG83qg  
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public void setSFileName(String value) LSlaz  
{ Tk$rwTCl  
sFileName = value; mfFC@~|g  
} x68J [; jm  
D/:~#)  
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public int getNSplitter() l
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{ fF[n?:VV  
return nSplitter; _X;^'mqf~  
} hD{+V!{  
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(ZQ{%-i?qR  
public void setNSplitter(int nCount) ?VEJk,/k  
{ nf+8OH7  
nSplitter = nCount; \.myLkm  
} )XMSQ ="m  
} 5[`!\vCiZ  
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ka  
$5r[YdnY<  
/* ,$Qa]UN5Q  
**Utility.java \hQ[5>  
*/ J6Hw05%0=  
package NetFox; `B) ~  
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public class Utility { =+~e44!~D  
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public Utility() LT!B]y  
{ K6@QZc5.!  
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} ~-GgVi*I  
c 6}d{B[  
//线程睡眠 \:8~na+(  
public static void sleep(int nSecond) If\u^c  
{ }DxXt  
try{ Y4){{bEp  
Thread.sleep(nSecond); Wd_bDZQ  
} $6XSW  
catch(Exception e) %Z 9<La  
{  IKKd  
e.printStackTrace (); r|:|\"Yk  
} yX$I<L<Suz  
} -2o4v#d  
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//日志 w3PE.A"Q  
public static void log(String sMsg) m'KY;C  
{ (u@[}!  
System.err.println(sMsg); l]W
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} ^6#FqK+{u  
Q
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YM 0f_G=
 
public static void log(int sMsg) Um)0jT  
{ yAU[A  
System.err.println(sMsg); 6%JKY
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} %Xh/16X${  
} as)2ny!u  
^ox^gw)  
/v:g' #n  
/* zPe4WE|  
**TestMethod.java $/}*HWVZ  
*/ M-K<w(,X
 
package NetFox; ?1?^>M  
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}el.qZ  
public class TestMethod { "L1cHP~d  
wA+J49  
F_/]9tz?;  
public TestMethod() mAhtC*  
{ ///xx/weblogic60b2_win.exe Dp6]!;kx  
try{ bESmKe(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); XrYMv WT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7B_;YT  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i@6MO'y  
fileFetch.start(); L5
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} =%znY`0b56  
catch(Exception e){e.printStackTrace ();} Kf76./  
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} C?#if;c  
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public static void main(String[] args)
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{ k~>9,=::d  
new TestMethod(); n&iWYECz  
} l$z[Vh^UU<  
} (zWzF_v  
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