http断点续传简单实现（java)

/* Apj[z2nr  
**SiteFileFetch.java T(,@]=d,DD  
*/ X#Ob^E%J  
package NetFox; /;vHAtt;f  
import java.io.*; [+8*}03  
import java.net.*; 6q8PLyIp  
-?l`LbD  
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public class SiteFileFetch extends Thread { 9R">l5u  
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SiteInfoBean siteInfoBean = null; //文件信息Bean P,b&

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long[] nStartPos; //开始位置 &-w.rF@  
long[] nEndPos; //结束位置 )c?nh3D  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x0%yz+i{:  
long nFileLength; //文件长度 @iMF&\KC  
boolean bFirst = true; //是否第一次取文件 GvvKM=1  
boolean bStop = false; //停止标志 OI8}v  
File tmpFile; //文件下载的临时信息 #2lvRJB  
DataOutputStream output; //输出到文件的输出流 >^
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2G<XA  
public SiteFileFetch(SiteInfoBean bean) throws IOException J qmL|
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{ 4CtWEq  
siteInfoBean = bean; [>U2!4=$M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2<@g *  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); kZ]pV=\Y*  
if(tmpFile.exists ()) -%Ce  
{ d'H gek{T  
bFirst = false; mi7~(V>  
read_nPos(); OT$++cj^  
} ^N7 C/" p  
else PRNq8nmxC  
{ GctV  
nStartPos = new long[bean.getNSplitter()]; "c?31$6  
nEndPos = new long[bean.getNSplitter()]; a8G<x<  
} r:Q=6j,  
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} U_.}V  
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public void run() _ b</ ::Tp  
{ SSyARR+;c  
//获得文件长度 ykH@kv Qt  
//分割文件 3OY(L`  
//实例FileSplitterFetch  p:eaZ  
//启动FileSplitterFetch线程 -N6ek`  
//等待子线程返回 e\f\CMb  
try{ tA,J~|+f:  
if(bFirst) D~|q^Ms,%  
{ q}0I`$MU  
nFileLength = getFileSize(); (ip3{d{CT]  
if(nFileLength == -1) 9 g- 8u+&  
{ QUfF>,[sv  
System.err.println("File Length is not known!"); k,; (`L  
} rW_cLdh]#  
else if(nFileLength == -2) &&m1_K  
{ .2_
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System.err.println("File is not access!"); -w8?Ur1x:  
} ]{#Xcqx  
else #XqiXM~^R  
{ opu)9]`z  
for(int i=0;i<nStartPos.length;i++) 2R^Eea  
{ %K7;ePu  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); iP:^nt?  
} tw.z5  
for(int i=0;i<nEndPos.length-1;i++) qV,x)y:V  
{ v6E5#pse8  
nEndPos = nStartPos[i+1]; <Lt"e8Z>x  
} E
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nEndPos[nEndPos.length-1] = nFileLength; /F''4%S?E  
} C7}iwklcsa  
} L `=*Pwcj  
,JTyOBB<I  
"?W8o[c+  
//启动子线程 l
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7s2*VKr  
for(int i=0;i<nStartPos.length;i++) ?P#\CW  
{ e eyZ$n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cS@p`A7Tpo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), oYJ<.Yxeb  
nStartPos,nEndPos,i); wAzaxeV=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k)y<iHR_o  
fileSplitterFetch.start(); 322-'S3<  
} ed3wj3@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YB^m!A),I[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m6 Y0,9
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ycvgF6Me<  
nEndPos = " + nFileLength); /rK/l  
// fileSplitterFetch[nPos.length-1].start(); V%C'@m(/SZ  
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s.KfMJ"u[  
//等待子线程结束 77 Z:!J|  
//int count = 0; <;jg/  
//是否结束while循环 fi&>;0?7  
boolean breakWhile = false; MI.OOoP3a  
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while(!bStop) U^K8^an$  
{ Z*v`kl  
write_nPos(); @ Yo*h"s  
Utility.sleep(500); f3h]t0M  
breakWhile = true; Imyw-8/;  
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for(int i=0;i<nStartPos.length;i++) XB:E<I'q!3  
{ jxYze/I  
if(!fileSplitterFetch.bDownOver) UF}Ji#fq
n  
{ e<~bDFH  
breakWhile = false; #H5+8W  
break; bhfKhXh8  
} ,XN4Iy#BZl  
} 0fV}n:4Pq  
if(breakWhile) %/_E8GE  
break; H6KBXMYO  
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8hSw4S"$  
//count++; +]~}kvk:  
//if(count>4) @f,/K1
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// siteStop(); G1I<B  
} _b 
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System.err.println("文件下载结束！"); 5UG"i_TC  
} `?d` #)Ck  
catch(Exception e){e.printStackTrace ();}
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} zP|^@Homk  
sn'E}.uhXH  
I-Am9\  
//获得文件长度 Ypinbej  
public long getFileSize() N7)K\)DS!z  
{ 3XncEdy_  
int nFileLength = -1; ]7q|) S\  
try{ DJ1!Xuu  
URL url = new URL(siteInfoBean.getSSiteURL()); "DX2Mu=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9
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httpConnection.setRequestProperty("User-Agent","NetFox"); Yq{R*HO  
i nk
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int responseCode=httpConnection.getResponseCode(); meGLT/   
if(responseCode>=400) I:;umyRH  
{ J M;WCV%NM  
processErrorCode(responseCode); I`x[1%y2 F  
return -2; //-2 represent access is error U@53VmrOy  
} uu/2C \n}  
|!CAxE0d$B  
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String sHeader; K :>O X  
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for(int i=1;;i++) yIWgC[  
{ 1=PTiDMJ<*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .kB!',v\  
//Utility.log(in.readLine()); vb9C&#  
sHeader=httpConnection.getHeaderFieldKey(i); ,G[Y< ~Hy  
if(sHeader!=null) 4v9d& m!<  
{ }q,dJE  
if(sHeader.equals("Content-Length")) z:&/O&?  
{ ju1B._48  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1-|aeJ  
break; R*2F)e\|  
} Lyit`j~yH  
} V
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else &=XK:+  
break; ;s-@m<  
} 45OAJ?N  
} $VF$Ok>  
catch(IOException e){e.printStackTrace ();} %pqB/  
catch(Exception e){e.printStackTrace ();} Pz0TAb  
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Utility.log(nFileLength); ~wO-Hgd  
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return nFileLength; YOUB%N9+  
} }Yc5U,A;  
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2\;/mQI2A  
//保存下载信息（文件指针位置） WdB\n/BWB  
private void write_nPos() k|{ 4"4r  
{ B{p74 >  
try{ Vhr6bu]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8H`L8: CM  
output.writeInt(nStartPos.length); [B+:)i  
for(int i=0;i<nStartPos.length;i++) >(.Y%$9"E  
{ 4YR{ *  
// output.writeLong(nPos); _dmG#_1  
output.writeLong(fileSplitterFetch.nStartPos); 9,JWi{lIv  
output.writeLong(fileSplitterFetch.nEndPos); +L@\/=;G  
} K\59vtga  
output.close(); B2|0.G|[j  
} @^o7UzS4z  
catch(IOException e){e.printStackTrace ();} _O;4>  
catch(Exception e){e.printStackTrace ();} D@:'*Z(  
} S_ UAz  
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Z
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//读取保存的下载信息（文件指针位置） 0s\ -iub=d  
private void read_nPos() <q>d@Foi  
{ Y=g]\%-PB  
try{ VR\}*@pNp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L#
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int nCount = input.readInt(); *N}$~N  
nStartPos = new long[nCount]; y.6/x?Qc  
nEndPos = new long[nCount]; t\TxK7i  
for(int i=0;i<nStartPos.length;i++) P}qpy\/(4  
{ 9*huO#  
nStartPos = input.readLong(); w7&.Uqjf  
nEndPos = input.readLong(); &%;n9K  
} O:GAS [O`  
input.close(); *'-t_F';  
} ^E:-Uy  
catch(IOException e){e.printStackTrace ();} %5DM ew  
catch(Exception e){e.printStackTrace ();} &I(\:|`o  
} \=]`X2Ld  
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private void processErrorCode(int nErrorCode) DvB{N`COd  
{ g_N^Y  
System.err.println("Error Code : " + nErrorCode); zSU,le  
} G_,9h!e  
L
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0fn*;f8{XJ  
//停止文件下载 &/ED.K  
public void siteStop() jD}h`(bE  
{ }f14# y;  
bStop = true; gIusp917  
for(int i=0;i<nStartPos.length;i++) *Uj;a.  
fileSplitterFetch.splitterStop(); G%;>_E  
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} `]]<.>R  
} EP>Lh7E9n  
//负责部分文件的抓取 ,\cV,$  
**FileSplitterFetch.java ,+4T7 UR  
*/ :]]x^wony~  
package NetFox; _aF8Us  
-!\%##r7~  
@ =~k[
o  
import java.io.*; 1K<}  
import java.net.*; }LKD9U5;8  
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public class FileSplitterFetch extends Thread { 0B!(i.w  
5`+9<8V  
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String sURL; //File URL H!u8+  
long nStartPos; //File Snippet Start Position ]1Wxa?  
long nEndPos; //File Snippet End Position yiI oqvP  
int nThreadID; //Thread's ID <tZZ]Y]  
boolean bDownOver = false; //Downing is over oH?:(S(   
boolean bStop = false; //Stop identical f\_PNZCc  
FileAccessI fileAccessI = null; //File Access interface 5N%d Les  
*A
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException U5H%wA['m  
{ Z|Rc54Ct  
this.sURL = sURL; Y6H?ZO
q  
this.nStartPos = nStart; ,>7dIJqzw  
this.nEndPos = nEnd; '@ Y@Fs  
nThreadID = id; ng9e)lU~*b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 zPqJeYK  
} N{Z+
 
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public void run() OUF%DMl4  
{ 7x>^ip"7  
while(nStartPos < nEndPos && !bStop) `N.:3]B t  
{ tz
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try{ _.V5-iN  
URL url = new URL(sURL); ;<Hk Cd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +~iiy;i(  
httpConnection.setRequestProperty("User-Agent","NetFox"); Wq<oP  
String sProperty = "bytes="+nStartPos+"-"; hx9t{Zi  
httpConnection.setRequestProperty("RANGE",sProperty); ?{aJ#w  
Utility.log(sProperty); 7`t"fS  
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[1kQ-Ko`  
InputStream input = httpConnection.getInputStream(); IAwS39B  
//logResponseHead(httpConnection); (XmmbAbVom  
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byte[] b = new byte[1024]; S%}G 8Ty  
int nRead; =dA]nM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) l+P!I{n  
{ T*%GeY [  
nStartPos += fileAccessI.write(b,0,nRead); \L~^c1s3r  
//if(nThreadID == 1) >\<eR]12  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G6a 2]  
} c( U,FUS  
(:OMt2{r  
iY07lvG<  
Utility.log("Thread " + nThreadID + " is over!"); \UZGXk  
bDownOver = true; 3\j`g  
//nPos = fileAccessI.write (b,0,nRead); 1-?i*C  
} ;6pB7N  
catch(Exception e){e.printStackTrace ();} "kFH*I+v  
} U?f-/@fc  
} vk
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B//*hH >F  
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//打印回应的头信息 E7\K{]  
public void logResponseHead(HttpURLConnection con) Sxc)~y  
{ Fy<:iv0>t  
for(int i=1;;i++) ZwsQ}5
 
{ L%Zr3Ct  
String header=con.getHeaderFieldKey(i); ef '?O  
if(header!=null) N7lg6$s Aj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); z*jaA;#  
Utility.log(header+" : "+con.getHeaderField(header)); &2XH.$Q  
else KMy"DVqE  
break; oc] C+l  
} PZqp;!:xz  
} p P@q `  
[q!]Ds" _  
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public void splitterStop() PjBAf'  
{ Lw[=pe0
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bStop = true; w%qnH e9  
} }FS_"0  
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80lhhqRC  
} #N`G2}1J  
3>7{Q_5  
,i}EGW,9q  
/* )-[$m%  
**FileAccess.java tKUW  
*//文件访问(定位，写) 02[m{a-  
package NetFox; ](R /4  
import java.io.*; KH?6O%d  
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!c)F;  
public class FileAccessI implements Serializable{ $Q#n'#c  
k%~;mu"4}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 J#Y0R"fo  
RandomAccessFile oSavedFile; dF51_Kk  
long nPos; 5TpvJ1G  
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public FileAccessI() throws IOException '6NrL;  
{ LbJf5xdi  
this("",0); t|oIzjKE/  
} 7WSP0Xyz  
VOr:G85*s  
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public FileAccessI(String sName,long nPos) throws IOException FYFlh^}  
{ )=gU~UV  
oSavedFile = new RandomAccessFile(sName,"rw"); .zdaY, U  
this.nPos = nPos; [g}#R#Y)  
oSavedFile.seek(nPos); <ivG(a*=]  
} kdGq\k,  
{06-h %qr  
`,~'T [  
public synchronized int write(byte[] b,int nStart,int nLen) d`V.i6u  
{ I@VzH(da\  
int n = -1; :](#W@r  
try{ :!t4.ko  
oSavedFile.write(b,nStart,nLen); P4yUm(@  
n = nLen; /8]
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} CzreX3i  
catch(IOException e) uHacu<$=  
{ pFMjfWD,C  
e.printStackTrace (); O{c#&/.K  
} j< h1s%  
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return n; H1?C:R  
} PtQ[({d3R  
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} vCt][WX(  
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/* /#{~aCOi)  
**SiteInfoBean.java Sru0j/|H\  
*/ y[Dgyt  
package NetFox; t5b cQ@Y  
&.2
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\rh+\9(  
public class SiteInfoBean { dzbbFvG  
njJTEUd">  
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private String sSiteURL; //Site's URL 9-{.WZ  
private String sFilePath; //Saved File's Path +Q5'!@8  
private String sFileName; //Saved File's Name K~-V([tWg  
private int nSplitter; //Count of Splited Downloading File < <0[PJ  
>2K'!@~'  
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public SiteInfoBean() 3:$@DZT$  
{//nSplitter的缺省值为5 m7A3i<6p  
//default value of nSplitter is 5 P^Og(F8;  
this("","","",5); sng6U;Z  
} z\, lPwB2  
]o'dr r  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) NODg_J~T  
{ .8'uIA{_2  
sSiteURL= sURL; )9/i
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sFilePath = sPath; 2XUIC
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sFileName = sName; aRn""3[  
this.nSplitter = nSpiltter; Fm&f  
x)%"i)  
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} v?nGAn  

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public String getSSiteURL() O]="ggq&  
{ . Z9c.E{  
return sSiteURL; if1)AE-  
} eA(FWO  
(yT&&_zY4  
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public void setSSiteURL(String value) E6Uj8]P`  
{ h6`VU`pPI  
sSiteURL = value; mMu+MXTk<  
} {~\:4  
6khm@}}  
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public String getSFilePath() WwKpZ67$R  
{ 4w 7vgB  
return sFilePath; Z]Z&PbP  
} 7Y4D9pw  
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public void setSFilePath(String value) cqb6]  
{ 5ry[Lgg  
sFilePath = value; .o<9[d"  
} 2of+KI:
 
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_$}@hD*R~  
public String getSFileName() g'-hSV/@}@  
{ 5!6iAS+I  
return sFileName; ph~#{B(\  
} oO;<$wx2t  
,>pv>)u{  
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public void setSFileName(String value) fB4z
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{ q}"HxMJ  
sFileName = value; [#:yOZt  
} f[OJqk  
r)G)i;;~*  
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public int getNSplitter() eQ#"-i  
{ _z"\3hZ  
return nSplitter; <z wI@i  
} 2m&?t_W  
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1eS@ihkP  
public void setNSplitter(int nCount) Fow{-cs_p  
{ *^\u%Ir"  
nSplitter = nCount; 3KKq1][  
} aQ1n1OBr  
} dpcv'cRfw  
vrsOA@ee3H  
**n109R  
/* UzkX;UA  
**Utility.java hl+ T  
*/ E{B40E~4  
package NetFox; +|O&k  
I9cZZ`vs  
rf2-owWN  
public class Utility { P76QHBbl  
~uO9>(?D  
k/%n7 ;1  
public Utility() f{R/rb&iB  
{ }RkD7  
]~m2#g%  
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} MSS0Sx<f  
</h}2x  
//线程睡眠 d?OsVT;U  
public static void sleep(int nSecond) h4? 'd+
K  
{ v6KF0mqA&  
try{ )u5+<OG}=  
Thread.sleep(nSecond); j1P#({z[  
} ^WIGd"^  
catch(Exception e) Vg? 1&8>  
{ r(/+- t  
e.printStackTrace (); Hz3KoO &  
} @EB2I+[  
} +S}/6dg  
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//日志 M!b"c4|<  
public static void log(String sMsg) 1mz72K  
{ THDyb9_g  
System.err.println(sMsg); R9lb<`  
} 
$"x~p1P  
[>U =P`  
si3@R?WR6*  
public static void log(int sMsg) ir3EA'_>N  
{ ~i/K7qZ  
System.err.println(sMsg); RL3G7
;X  
} Oi4tG&q  
} a/H|/CB3  
'nh^'i&0.  
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/* 
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**TestMethod.java nf9NJ_8}4H  
*/ |jE0H!j  
package NetFox; xnD"LK  
\J,pV  
'?MT"G  
public class TestMethod { $:SSm$k  
L9":=  
&x<y4ORH|  
public TestMethod() ._
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{ ///xx/weblogic60b2_win.exe ct![eWsuB  
try{ jQrw^6C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <mX EX`?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?."YP[;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d/Y#oVI  
fileFetch.start(); D>efr8Qd@  
} 24Uvi:B?~  
catch(Exception e){e.printStackTrace ();} /[RO>Z9  
s'Wu \r'  
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} 5>u,Qh  
x|lX1Mh$  
9B<aYp)  
public static void main(String[] args) %{HeXe  
{ ;2jH;$HZ  
new TestMethod(); FEwPLViso  
} pW4$$2S?9  
} @[. 0,
 
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