http断点续传简单实现（java)

/* -I=l8m6L  
**SiteFileFetch.java P 3'O/!  
*/ J(6oL   
package NetFox; R
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import java.io.*; '}$Dgp6e  
import java.net.*; &iV,W4  
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public class SiteFileFetch extends Thread { ~*wk6&|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean tPF.r  
long[] nStartPos; //开始位置 y99mC$"Ee`  
long[] nEndPos; //结束位置 !/wtYI-`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 LGtIm7  
long nFileLength; //文件长度 ,{mCf^  
boolean bFirst = true; //是否第一次取文件 rOVVL%@QqJ  
boolean bStop = false; //停止标志 D gaMO,  
File tmpFile; //文件下载的临时信息 hodgDrmO/  
DataOutputStream output; //输出到文件的输出流 O6OP =K!t:  
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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 y~\oTJb  
{ -(=eM3o-9m  
siteInfoBean = bean; a0#J9O_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); tdu$pC6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }1upi=+aE  
if(tmpFile.exists ()) 1aTB%F  
{ (UxW;  
bFirst = false; _FWBUZ;N  
read_nPos(); <Sr  
} [)TRTxFb  
else r! MWbFw|X  
{ ZEx}$<)_  
nStartPos = new long[bean.getNSplitter()]; Ll4g[8  
nEndPos = new long[bean.getNSplitter()]; <q@a~'Ai?!  
} sL$:
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} c-0#w=  
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public void run() %xyou:~0zs  
{ b"{'T]"*j  
//获得文件长度 3(,?S$>  
//分割文件 rQ qW_t%  
//实例FileSplitterFetch w {3<{  
//启动FileSplitterFetch线程 )z28=
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//等待子线程返回 1waTTT?"Ho  
try{ L}pt)w*V1j  
if(bFirst) 3zc
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{ Zo~  
nFileLength = getFileSize(); {fjdr  
if(nFileLength == -1) XY3v_5~/1F  
{ V6,H}k  
System.err.println("File Length is not known!"); pWJFz-  
} mrF58Uq;A  
else if(nFileLength == -2)
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{ lE(a%'36  
System.err.println("File is not access!"); W~7A+=&  
} :BV6y|J9O^  
else B e0ND2oo  
{ M]2]\km  
for(int i=0;i<nStartPos.length;i++) )O@]uY  
{ |$ lM#Ua  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); HK0!P*  
} 4?q
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for(int i=0;i<nEndPos.length-1;i++) /Y2}a<3&0  
{ EZ`te0[  
nEndPos = nStartPos[i+1]; %/zbgS`  
} ^Xq 6:
 
nEndPos[nEndPos.length-1] = nFileLength; 2Tp1n8FV  
} =*c7i]@}  
} 2$g6}A`r  
%|q>pin2  
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//启动子线程 %1xb,g KO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r\-uJ~8N  
for(int i=0;i<nStartPos.length;i++) 6"J? #  
{ tne ST.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B][U4WJ)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ki$MpA3j  
nStartPos,nEndPos,i); PIoLywpRn  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j2StXq3  
fileSplitterFetch.start(); Z
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} '}Z~JYa0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ][+#;avU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); zck#tht4 n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Vr`R>S,-
 
nEndPos = " + nFileLength);  ~-_kM  
// fileSplitterFetch[nPos.length-1].start(); EIf5(/jo  
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//等待子线程结束 Mh:L$f0A%O  
//int count = 0; KWowN;  
//是否结束while循环 4C61GB?Vy  
boolean breakWhile = false; j7$e28|_n  
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while(!bStop) -pf}  
{ t^R][Ay&  
write_nPos(); (:TjoXXiY  
Utility.sleep(500); DEG[Z7Ju  
breakWhile = true; M"p  
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for(int i=0;i<nStartPos.length;i++) ~J wb`g.  
{ ; >hNt  
if(!fileSplitterFetch.bDownOver) &5fJPv &  
{ c'>/  
breakWhile = false; f_jo+z{-ik  
break; >z{d0
{\  
} XHK<AO^  
} ;c-(ObSm  
if(breakWhile) CrC^1K  
break; 9kN}c
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//count++; \o}xF@sM5  
//if(count>4) -3t7*  
// siteStop(); 3G,Oba[$<  
} [YF>:ydk  
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System.err.println("文件下载结束！"); 591>rh)  
} +7D|4  
catch(Exception e){e.printStackTrace ();} 0=@?ob7  
} OE_XCZ!5P  
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[')m|u~FS4  
//获得文件长度 "CSsCA$/  
public long getFileSize() A-Sv;/yD_  
{ L-jJg,eY  
int nFileLength = -1; h58`XH  
try{ Zd^rNHhA  
URL url = new URL(siteInfoBean.getSSiteURL()); s@&`f{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rdl;M>0@  
httpConnection.setRequestProperty("User-Agent","NetFox"); y I HXg#  
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int responseCode=httpConnection.getResponseCode(); #I{h\x><?  
if(responseCode>=400) :1cV;gJ  
{ A
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processErrorCode(responseCode); FcR=v0),  
return -2; //-2 represent access is error nrL9 E'F'  
} /\ y?Y  
3
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String sHeader; ?]|\4]zV  
/ ;$#d}R  
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for(int i=1;;i++) iEVb"w059  
{ BWeA@v  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7`-Zuf  
//Utility.log(in.readLine()); 3c#BKHNC
 
sHeader=httpConnection.getHeaderFieldKey(i); %+@O#P  
if(sHeader!=null) @K\~O__  
{ q}`${3qQ3  
if(sHeader.equals("Content-Length")) nW PF6V>  
{ /7aBDc-v  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =e/9&993  
break; -V-RP;">  
} j`JMeCG=Ee  
} V, Z|tB^  
else iZ#!O*>  
break; ]{)a,c NG  
} 4,bv)Im+ `  
} Ttu2skcv  
catch(IOException e){e.printStackTrace ();} p#ol*m5wE  
catch(Exception e){e.printStackTrace ();} nno}e/zqf  
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Utility.log(nFileLength); 9v;Vv0k_  
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return nFileLength; #o=y?(  
} j#X
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//保存下载信息（文件指针位置） N+m)/x =:  
private void write_nPos() AYt%`Y.!  
{ 3C?f(J}  
try{ gy,ht3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Fu SL}P  
output.writeInt(nStartPos.length); ZOft.P O  
for(int i=0;i<nStartPos.length;i++) sd,J3  
{ $h2){*5E{  
// output.writeLong(nPos); `>gd&u  
output.writeLong(fileSplitterFetch.nStartPos); K$&s=Hm  
output.writeLong(fileSplitterFetch.nEndPos); k52/w)Ro,$  
} )bS~1n_0  
output.close(); @GBxL*e  
} u8gS<\  
catch(IOException e){e.printStackTrace ();} KK1gNC4R  
catch(Exception e){e.printStackTrace ();} bV(Y`g  
} O}+.U<V  
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//读取保存的下载信息（文件指针位置） 1{r3#MVL  
private void read_nPos() 4E;VM{  
{ B( ]M&  
try{ Lrta/SU*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @XgKYm   
int nCount = input.readInt(); w zYzug  
nStartPos = new long[nCount]; 7Fz
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nEndPos = new long[nCount]; Of-Rx/
 
for(int i=0;i<nStartPos.length;i++) p6]7&{>  
{ cQ/5
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nStartPos = input.readLong(); R{WE\T'  
nEndPos = input.readLong(); !Z`j2 e}  
} aUzBV\Yd}  
input.close(); w&$`cD  
} MC?,UDNd%  
catch(IOException e){e.printStackTrace ();} gcE|#1>  
catch(Exception e){e.printStackTrace ();} #D<C )Q  
} bP8Sj16q  
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private void processErrorCode(int nErrorCode) 1/RsptN"v  
{ aK&b{d  
System.err.println("Error Code : " + nErrorCode); jK!Au  
} '= _/1F*q  
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//停止文件下载 jq-p;-i  
public void siteStop() DQNnNsP:M-  
{ 3 *d"B tg  
bStop = true; ?{\nf7Y  
for(int i=0;i<nStartPos.length;i++) ^$%S &W  
fileSplitterFetch.splitterStop(); Ky|88~}:C9  
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} ?i)f^O  
} l,R/Gl  
//负责部分文件的抓取 XxT#X3D/,"  
**FileSplitterFetch.java P<PJ)>  
*/ $$D}I*^Dt  
package NetFox; +awW3^1Ed  
*-+&[P]m  
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import java.io.*; CAWA3fcQp  
import java.net.*; iocI:b<  
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public class FileSplitterFetch extends Thread { S\''e`Eb"5  
;KOLNi-B&  
RSr %n1  
String sURL; //File URL I[=j&rK`  
long nStartPos; //File Snippet Start Position @|Fg,N<Y]  
long nEndPos; //File Snippet End Position )!Jc3%(B  
int nThreadID; //Thread's ID 3,>0a  
boolean bDownOver = false; //Downing is over a#^B2  
boolean bStop = false; //Stop identical sJ#4(r`  
FileAccessI fileAccessI = null; //File Access interface * 1T&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vbkI^+=,YY  
{ z3`-plE  
this.sURL = sURL; 4FEk5D  
this.nStartPos = nStart; ?f#y1m  
this.nEndPos = nEnd; 7q?9Tj3  
nThreadID = id; F|F]970  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 AcS|c:3MUy  
} O>qll6]{@  
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public void run() x N=i]~  
{ m*ISa(#(,  
while(nStartPos < nEndPos && !bStop) ]P#XVDn+;  
{ H70LhN  
{SwQ[$k=_  
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try{ i#7DR>XF/  
URL url = new URL(sURL); D Gr> 2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BsBK@+ZyI  
httpConnection.setRequestProperty("User-Agent","NetFox"); yN~dU0.G6!  
String sProperty = "bytes="+nStartPos+"-"; ^w(p8G_-w  
httpConnection.setRequestProperty("RANGE",sProperty); s<*XNNE7  
Utility.log(sProperty); 7bqBk,`9  
7]^M>#  
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InputStream input = httpConnection.getInputStream(); pR `>b 3  
//logResponseHead(httpConnection); 6Ca(U'  
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byte[] b = new byte[1024]; Ae mDJ8Y  
int nRead; J+[_Wd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dODt(J}%  
{ Ks=>K(V6  
nStartPos += fileAccessI.write(b,0,nRead); h lkn%  
//if(nThreadID == 1)
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Rz(QC\(  
} -9"['-WH,  
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Utility.log("Thread " + nThreadID + " is over!"); NxjB/N  
bDownOver = true; Lk~ho?^`  
//nPos = fileAccessI.write (b,0,nRead); OTC!wI g  
} pF&(7u  
catch(Exception e){e.printStackTrace ();} pcau}5 .  
} !g Z67  
} LAVAFlK5  
;w:M`#2  
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//打印回应的头信息 UQ'\7OS  
public void logResponseHead(HttpURLConnection con) #~SP)Ukp  
{ 1=#q5dZ]  
for(int i=1;;i++) /3;4#:Kkw  
{ Ge,;8N88  
String header=con.getHeaderFieldKey(i); Xua+cVc\y  
if(header!=null) 
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); yMyE s8  
Utility.log(header+" : "+con.getHeaderField(header)); 7G.#O}).b  
else *&?c(JU;<  
break; HU
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} K/A*<<r ~  
} 8d?g]DEN)6  
"5;;)\o~  
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public void splitterStop() hZh9uI7.  
{ ^
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bStop = true; ,z3{u162  
} -`<kCW"  
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!lEY=1nHOJ  
} uvtF_P/  
.{
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/* )ap_Z6  
**FileAccess.java + ` s@  
*//文件访问(定位，写) r)Ap8?
+  
package NetFox; 8#(Q_  
import java.io.*; V+Cwzc^j  
/DQc&.jK  
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public class FileAccessI implements Serializable{ !O-C,uSm  
P8^hBv*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 oo.!.Kv  
RandomAccessFile oSavedFile; _cy2z  
long nPos; ,Vh.T&X5  
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public FileAccessI() throws IOException _Dym{!t  
{ A$#p%yb  
this("",0); 6fd+Q /  
} xZ|Y?R5m  
*GxTX3i}vc  
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public FileAccessI(String sName,long nPos) throws IOException }| J79s2M  
{ {Z3dF)>  
oSavedFile = new RandomAccessFile(sName,"rw"); |~'IM3Jw(Y  
this.nPos = nPos; "`M?R;DH  
oSavedFile.seek(nPos); >tO`r.5u9  
} RY c!~Wh~Y  
t]$P1*I  
= QQ5f5\l  
public synchronized int write(byte[] b,int nStart,int nLen) Y^ kXSU  
{ vFE;D@bz:  
int n = -1; Nc+,&R13m  
try{ o4*+T8[|5  
oSavedFile.write(b,nStart,nLen); ;3\3q1oX  
n = nLen; w;k):;$  
} >Y_*%QGH_  
catch(IOException e) Jd5:{{Lb  
{ A,\6nO67  
e.printStackTrace (); k$H%.l;E  
} H|RT?Q  
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return n; K$M^gh0  
} qw@puw@D  
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} _<a7CCg  
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/* |tv"B@`  
**SiteInfoBean.java A|L8P  
*/ slg ]#Dy  
package NetFox; HPb]Zj  
,$'])A?$  
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public class SiteInfoBean { Ga#:P F0  
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private String sSiteURL; //Site's URL wY~&Q}U  
private String sFilePath; //Saved File's Path *uo'VJI7_,  
private String sFileName; //Saved File's Name vC1v"L;[o/  
private int nSplitter; //Count of Splited Downloading File TjHwjRa  
,0E{h}(  
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public SiteInfoBean() z)z{3rR|PW  
{//nSplitter的缺省值为5 ccLq+a|  
//default value of nSplitter is 5 9G{;?c  
this("","","",5); *xON W  
} K_2|_MLlZ  
EL8NZ%:v:  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .&9 i  
{ ]8T |f  
sSiteURL= sURL; hQ(q
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sFilePath = sPath; :WSDf VX  
sFileName = sName; DyQM>xw)t  
this.nSplitter = nSpiltter; Wx~k&[&E  
<{2e#
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} X66VU  
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INkD=tX  
public String getSSiteURL() ?Y:8eD"*  
{ zN{K5<7o  
return sSiteURL; \0mb 3Q'  
} ~(pmLZ<GW}  
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public void setSSiteURL(String value) =QK$0r]c'k  
{ wMdal:n^  
sSiteURL = value; GrTulN?  
} `)T~psT  
es>W$QKlo  
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public String getSFilePath() 9*E7}b,  
{ txcf=)@>V  
return sFilePath; g8w2Vz2/  
} )ZBY* lk9  
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++aL4:  
public void setSFilePath(String value) )u/H>;L P  
{ 2*N_5&9mE  
sFilePath = value; OM|Fwr$  
} .Wq@gV  
K"b`#xN(t  
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public String getSFileName()  ;b`[&g  
{ K =wBpLB  
return sFileName; XuD=E  
} rHf&:~   
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public void setSFileName(String value) Kh4$ wwn  
{ +<}0|Xl&  
sFileName = value; wWSdTLX  
} K{ \;2M  
`E!N9qI?t$  
"Vr[4&`  
public int getNSplitter() ]D@0|  
{ l#lF +Q;  
return nSplitter; &q`q4g&7  
} ,(.MmP`  
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public void setNSplitter(int nCount) =)E,8L  
{ 6m VuyI  
nSplitter = nCount; t^[8RhD  
} xB@|LtdO9;  
} { .*y  
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WHAQu]{  
/* gqR)IVk>%  
**Utility.java >@YtDl8R  
*/ WWL4`s  
package NetFox; jS;J:$>^  
/s-A?lw^2  
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public class Utility { nOQa_G]Gz  
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public Utility() ?KITC;\\  
{ 4*aZ>R2hO  
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} Yp0/Ab(v  
%0 #XPc("  
//线程睡眠 r?CI)Y;  
public static void sleep(int nSecond) 0QvT
 
{ ,=aJVb=C  
try{ ifo7%XPcg  
Thread.sleep(nSecond); 5OO'v07b  
} 4QIE8f Y  
catch(Exception e) 557(EM  
{ wHIj<"2  
e.printStackTrace (); %?aS#4jI  
} pGSai&  
} gPu2G/Y  
sHcTd>xS  
//日志 ~V/?H!r'{}  
public static void log(String sMsg) 2kv7UU#q2  
{ 11|Rdd+}  
System.err.println(sMsg); h(qQsxIOhS  
} pDQ}*  
lc_E!"1  
EwS!]h?  
public static void log(int sMsg) lpRR&
  
{ f30Pi1/h=c  
System.err.println(sMsg); 6YuY|JD  
} l<Q>N|1#k%  
} |oub!fG4  
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/* MG /,==  
**TestMethod.java cpt<WK}  
*/ +n
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package NetFox; kQaSbpNmH  
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1
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public class TestMethod { P/JK$nb  
l88A=iLgv  
kD) $2I?  
public TestMethod() }pa9%BQI  
{ ///xx/weblogic60b2_win.exe 4d_s%n?C  
try{ M7>(hVEAW'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P]i =r] i  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =<@\,xN>C  
SiteFileFetch fileFetch = new SiteFileFetch(bean); UZEI:k,dv  
fileFetch.start(); x f4{r+  
} $ n,Z  
catch(Exception e){e.printStackTrace ();} ^E6d`2w-  
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} >K# ,cxY  
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public static void main(String[] args) \@}#Gez  
{ ri1C-TJM)  
new TestMethod(); q8:{Nk  
} tRw@U4=y  
} WZ!WxX>zO  
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