http断点续传简单实现（java)

/* {gkY:$xnrG  
**SiteFileFetch.java yh'P17N|q  
*/ `0z8J*T]  
package NetFox; d7U%Q8?wUR  
import java.io.*; jqJ't)N  
import java.net.*; u$MXO].Q  
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public class SiteFileFetch extends Thread { B]lM69Hz  
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SiteInfoBean siteInfoBean = null; //文件信息Bean u]$e@Vw.  
long[] nStartPos; //开始位置 !\hUjM+(}  
long[] nEndPos; //结束位置 bMvHAtp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 j96\({;k  
long nFileLength; //文件长度 ,?KN;~t#vz  
boolean bFirst = true; //是否第一次取文件 +>BD^[^^  
boolean bStop = false; //停止标志 MRb6O
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File tmpFile; //文件下载的临时信息 h3YWqSj  
DataOutputStream output; //输出到文件的输出流 ?H0"*8C?Y  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） hVl^vw7o  
public SiteFileFetch(SiteInfoBean bean) throws IOException tYzpL  
{ 2l.qINyz  
siteInfoBean = bean; IPa)+ ZQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;%YAiW8{Xk  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (DTXc2)c  
if(tmpFile.exists ()) z<jH{AU  
{ lWRRB&8  
bFirst = false; F4|U\,g  
read_nPos(); U^~jB= =]  
} N_Q\+x}zq  
else ]N4?*S*jd)  
{ JIh:IR(ta  
nStartPos = new long[bean.getNSplitter()]; RbN# dI'  
nEndPos = new long[bean.getNSplitter()]; 9J(jbJ7p  
} Pq<]`9/w^w  
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} KwxO%/-}S  
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public void run() ZGgM-O1  
{ L; (J6p]h  
//获得文件长度 uk<JV*R=  
//分割文件 _I<LB0kgf.  
//实例FileSplitterFetch Ef"M e(  
//启动FileSplitterFetch线程 /s|4aro  
//等待子线程返回
+)U>mm,  
try{ --BS/L-  
if(bFirst) tjWf`#tH>H  
{ 4cQ|"sOzD  
nFileLength = getFileSize(); rI;84=v2&9  
if(nFileLength == -1) fKkH [  
{ d'UCPg<Y  
System.err.println("File Length is not known!"); -d8U Hc  
} 2r*Yd(e  
else if(nFileLength == -2) fb;y*-?#  
{ K)_DaTmi)  
System.err.println("File is not access!"); 6Sr}I,DG  
} cwC-)#R']  
else 1J?x2

 
{ 89+Q^79m  
for(int i=0;i<nStartPos.length;i++) & G8tb>q<V  
{ #Ks2a):8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =1e>$E
#  
} 4PDxmH]y  
for(int i=0;i<nEndPos.length-1;i++) -j"]1JLQ  
{ r{ }&* Y  
nEndPos = nStartPos[i+1]; %DIZgPd\  
} jFPD SR5  
nEndPos[nEndPos.length-1] = nFileLength; "inXHxqu/J  
} :+Okv$v4  
} k:sFI @g  
(N/KP+J$n  
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//启动子线程 #*)X+*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :}{,u6\  
for(int i=0;i<nStartPos.length;i++) @q<F_'7is  
{ m|%ly  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l/:23\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ow f:Kife  
nStartPos,nEndPos,i); $5v:z   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rc()Eo50  
fileSplitterFetch.start(); IuN:*P  
} 0.kQqy~5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  _YPu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); KoF_G[m  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H
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nEndPos = " + nFileLength); ^f_4w|u,+  
// fileSplitterFetch[nPos.length-1].start(); }Gi4`Es  
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//等待子线程结束 alz2F.%Y  
//int count = 0; 4pG!m&4]ze  
//是否结束while循环 n"dYN3dE  
boolean breakWhile = false; H=1Jq  
5A`T}~"X  
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while(!bStop) h&O8e;S#  
{ 2/4,iu(T`c  
write_nPos(); { 2\.  
Utility.sleep(500); `;BpdG(m  
breakWhile = true; MzX4/*ba  
lN,)T%[0-  
MB:*WA&  
for(int i=0;i<nStartPos.length;i++) +u|p<z  
{ SZ3UR  
if(!fileSplitterFetch.bDownOver) wbA<G&h~  
{ d@#wK~I
 
breakWhile = false; /\e&nYz  
break; f'Cx%  
} `S+B-I0  
} @teNT"  
if(breakWhile) G.y~*5?#  
break; .!Q
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+(  
+#=l{_Z,ZJ  
4 /Q4sE~<  
//count++; ed:[^#Lj  
//if(count>4) nQ}$jOU&  
// siteStop(); rUOl+p_47  
} *CS2ndp  
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System.err.println("文件下载结束！"); #V#sg}IhM?  
} _DAj$$ Ru4  
catch(Exception e){e.printStackTrace ();} -FrNk>  
} s?pd&_kOv3  
KV {J>J1  
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//获得文件长度 :$5$H  
public long getFileSize() =&YhA}l\O  
{ .sE5QRVc  
int nFileLength = -1; Q( g&/O  
try{ m\xlSNW'q  
URL url = new URL(siteInfoBean.getSSiteURL()); s6+`cC4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?@LqrKj11  
httpConnection.setRequestProperty("User-Agent","NetFox"); \2huDNW& !  
X^c2  
(>usa||  
int responseCode=httpConnection.getResponseCode(); ^j>w<ljzz  
if(responseCode>=400) TeXt'G=M  
{ /lqVMlz\77  
processErrorCode(responseCode); n,vs(ZL:  
return -2; //-2 represent access is error
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} uFl19  
b<1+q{0r  
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String sHeader; nlsif  
)ZqY`by!  
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for(int i=1;;i++) 6tKCY(#oO+  
{ >jH%n(TcC  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h-+GS%  
//Utility.log(in.readLine()); ?Ja&LNI9S  
sHeader=httpConnection.getHeaderFieldKey(i); E Zh.*u@^r  
if(sHeader!=null) #
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{ 75?z" i  
if(sHeader.equals("Content-Length")) G}8Zkz@+  
{ ~P;KO40K  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); hiBZZ+^[  
break; Rt=zqfJ  
}  roNRbA]  
} }?KfL$@$  
else ]sL)[o  
break; K#_x.:<J  
} ecIZ+G)k  
} & Y Y^Bd#  
catch(IOException e){e.printStackTrace ();} !wNj;S
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catch(Exception e){e.printStackTrace ();} 'wm :Xa  
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Utility.log(nFileLength); Tc.k0n%W:b  
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return nFileLength; Oll,;{<O  
} TP R$oO2  
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//保存下载信息（文件指针位置） ?CU6RC n  
private void write_nPos() Ww)p&don  
{ o +KDK{MD  
try{ pB0p?D)n  
output = new DataOutputStream(new FileOutputStream(tmpFile)); O~~
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output.writeInt(nStartPos.length); RF$2p4=[  
for(int i=0;i<nStartPos.length;i++) |X6/Y@N  
{ .,+TpPkc  
// output.writeLong(nPos); %!X9>i>  
output.writeLong(fileSplitterFetch.nStartPos); [3|&!:4g6  
output.writeLong(fileSplitterFetch.nEndPos); rO3.%B}  
} |0N
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output.close(); MFzJ 8^.1R  
} b;k3B7<  
catch(IOException e){e.printStackTrace ();} }fT5(+ Wo  
catch(Exception e){e.printStackTrace ();} 
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} 4Fs5@@>X  
RM|2PG1m  
l>){cI/D#  
//读取保存的下载信息（文件指针位置） {Uj-x -  
private void read_nPos() :XFr"aSt  
{ p()#+Xy  
try{ lC8Z@wkjO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2>+(OL4l  
int nCount = input.readInt(); `G0GWh)`x  
nStartPos = new long[nCount]; egXbe)ld  
nEndPos = new long[nCount]; [Zxv&$SQ  
for(int i=0;i<nStartPos.length;i++) Vl\8*!OL%  
{ ,*MAteD  
nStartPos = input.readLong(); (<KFA,  
nEndPos = input.readLong(); w 8BSY  
} W{W8\  
input.close(); 1LZ[i89&%  
} #X t|"Z  
catch(IOException e){e.printStackTrace ();} kH'zTO1  
catch(Exception e){e.printStackTrace ();} }N,$4h9Dj  
} +,|aIF  
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private void processErrorCode(int nErrorCode) !%X#;{  
{ :tf'Gw6v  
System.err.println("Error Code : " + nErrorCode); 6m$lK%P{1  
} MP_LdJM1E  
[L ?^+p>  
{16]8-pe  
//停止文件下载 q"9 2][}  
public void siteStop() &,8F!)[9  
{ J5Ovj,[EZ  
bStop = true; Y!qn[,q8  
for(int i=0;i<nStartPos.length;i++) r7^oqEp@B  
fileSplitterFetch.splitterStop(); $H8B%rT]  
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} YG_|L[/#  
} PK).)5sW  
//负责部分文件的抓取 d+o.J",E  
**FileSplitterFetch.java C2}f'  
*/ 4H4ui&|7u6  
package NetFox; 7z;X@+O}s  
E! GH$%:;  
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import java.io.*; v8
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import java.net.*; =J
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u  
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public class FileSplitterFetch extends Thread { '4ip~>3?w  
.L@gq/x)  
#1De#uZ  
String sURL; //File URL 1Eh6ti  
long nStartPos; //File Snippet Start Position Y?v{V>
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long nEndPos; //File Snippet End Position 8AQ__&nT  
int nThreadID; //Thread's ID wQ9?Z.-$  
boolean bDownOver = false; //Downing is over Ji)Ys ebV  
boolean bStop = false; //Stop identical c> 0R_  
FileAccessI fileAccessI = null; //File Access interface 363KU@`  
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3  
^).  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0fzHEL  
{ =1Hn<Xay0  
this.sURL = sURL; p?2^JJpUb  
this.nStartPos = nStart; R8-=N+hX  
this.nEndPos = nEnd; ?[<#>,W  
nThreadID = id; ]?%S0DO*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 g{^~g  
} ,GF]+nI89  
b4&l=^:e=  
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public void run() E?- ~*T
 
{ tj4/x7!  
while(nStartPos < nEndPos && !bStop) 3O*^[$vM  
{ Ozg,6&3ji  
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try{ _9C,N2a{C  
URL url = new URL(sURL); m+Kl   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (YM2Cv{4  
httpConnection.setRequestProperty("User-Agent","NetFox"); s}F.D^^G  
String sProperty = "bytes="+nStartPos+"-"; 1
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httpConnection.setRequestProperty("RANGE",sProperty); }qT{" *SC  
Utility.log(sProperty); MY}/h@  
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InputStream input = httpConnection.getInputStream(); Cto>~pV  
//logResponseHead(httpConnection); c] -  
+ib&6IU  

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byte[] b = new byte[1024]; h S)lQl:^  
int nRead; 2]]}
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) h~lps?.#b  
{ -AN5LE9-  
nStartPos += fileAccessI.write(b,0,nRead); GkpYf~\Q  
//if(nThreadID == 1)  SQ&}18Z~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D"gv:RojD  
} C8W_f( i~  
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Utility.log("Thread " + nThreadID + " is over!"); U(gYx@   
bDownOver = true; (mplo|>  
//nPos = fileAccessI.write (b,0,nRead); ~O~iP8T  
} EW`3$J;  
catch(Exception e){e.printStackTrace ();} } m"':f  
} .k$Yleg  
}
6l:uQz9  
cJf&R^[T  
)t((x  
//打印回应的头信息 l9e=dV:pH  
public void logResponseHead(HttpURLConnection con) 9k\M<jA  
{ *cZ7?  
for(int i=1;;i++) osc A\r  
{ fZoQQ[s  
String header=con.getHeaderFieldKey(i); :k-@w5(  
if(header!=null) g/(BV7V  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *eGG6$I  
Utility.log(header+" : "+con.getHeaderField(header)); Zv2]X-  
else "~S2XcR[ E  
break; 0{ _6le]  
} 'P*OzZ4>$  
} A'$>~Ev  
znDpg{U(  
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public void splitterStop() j
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{ \x:} |   
bStop = true; H_,4N_hL  
} m&yHtnt  
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} !1%Sf.`!_  
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/* '14 86q@[$  
**FileAccess.java v,Zoy|Lu  
*//文件访问(定位，写) [kTckZv  
package NetFox; nch
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import java.io.*; F|cli <  
1:Ff#Eq,s  
c>3j$D+  
public class FileAccessI implements Serializable{ (>,b5g  
Ls+vWfF=#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 zKI1  
RandomAccessFile oSavedFile; n1aOpz6`  
long nPos; dd6%3L{cn  
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tt CC] Q  
public FileAccessI() throws IOException r&ys?@+G  
{ VoQhzp6&  
this("",0); {6%-/$LX  
} scTt53v^  
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public FileAccessI(String sName,long nPos) throws IOException |tU wlc>  
{ rxs:)# ?A  
oSavedFile = new RandomAccessFile(sName,"rw"); 2R ^6L@fw  
this.nPos = nPos; _0ZU I^#  
oSavedFile.seek(nPos); k)[c!\a[i  
} R<vbhB/lU  
GHo mk##0E  
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public synchronized int write(byte[] b,int nStart,int nLen) I-=Ieq"R9  
{ _k;HhLj`  
int n = -1; 2G<XA  
try{ Sn^M[}we  
oSavedFile.write(b,nStart,nLen); t BG 9Mn  
n = nLen; ;JMmr-@  
} cnRg
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catch(IOException e) bvHQ#:}H  
{ bR1Q77<G\  
e.printStackTrace (); 7F_N{avr  
} kZ]pV=\Y*  
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return n; @6%7X7m  
} }$sTnea  
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} vT @25  
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:."6g)T  
/* B#}EYY  
**SiteInfoBean.java mxu!$wx  
*/ uHRxV"@}[1  
package NetFox; "c?31$6  
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public class SiteInfoBean { | +uc;[`  
th<>%e}5c  
Oqt{ uTI~  
private String sSiteURL; //Site's URL T\ukJ25!  
private String sFilePath; //Saved File's Path +JM@kdE5b  
private String sFileName; //Saved File's Name f*IvaY  
private int nSplitter; //Count of Splited Downloading File _ysakn  
!qHB?]  
yjq|8.L[ G  
public SiteInfoBean() 0LSJQ9\p  
{//nSplitter的缺省值为5 D #7q3s  
//default value of nSplitter is 5 P2 qC[1hYH  
this("","","",5); *cCj*Zr]  
} kY6_n4  
'cAS>s"$}V  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9'e<{mlM  
{  =zDvZ(5  
sSiteURL= sURL; ):nC%0V  
sFilePath = sPath; (_+ux1h6^  
sFileName = sName; [d-Y1  
this.nSplitter = nSpiltter; R=$}uDFmW  
$9xp@8b\_  
e.#,9  
} (d*||"  
a;nYR5f  
WS?Y8~+{5  
public String getSSiteURL() ?AQA>D#W  
{ ts("(zI1E  
return sSiteURL; \PFjw9s  
} ,H<nNBv3M  
9 g- 8u+&  
1'iQlnMO@  
public void setSSiteURL(String value) g6S-vSX,  
{ }RYPr  
sSiteURL = value; -}( o+!nl  
} DRTT3;,N  
"3|OB, <;:  
-j:yEZ4Oy  
public String getSFilePath() GU9p'E  
{ .2_
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return sFilePath; m(EVC}Y  
} &p*
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L/%{,7l<^?  
-^;,m=4{3  
public void setSFilePath(String value) l Ft&cy2  
{ tp }Bz&V  
sFilePath = value; wlslG^^(!  
} Fg'{K%t4  
,^ dpn  
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public String getSFileName() Nez '1  
{ x{GFCy7  
return sFileName; so| U&`G  
} <X
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0>e]i[P.  
public void setSFileName(String value) %nE%^Enw  
{ <]|!quY<*  
sFileName = value; yX%> %#$  
} 8<KC-|y.  
Ol>/^3a=  
/F''4%S?E  
public int getNSplitter() C@-cLk  
{ ^P A|RFP  
return nSplitter; hstGe>f[6  
} r>PKl'IbE  
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public void setNSplitter(int nCount) N pQOLX/<?  
{ {0AlQ6.@>  
nSplitter = nCount; d>c`hQ(V  
} [a}Idi` K  
} 8YgRJQZ!  
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/* ;TwqZw[.  
**Utility.java i.eMrzJ|  
*/ O'.{6H;t  
package NetFox; S&k/Pc  
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public class Utility { JS<w43/j  
f.E{s*z>  
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public Utility() xgM\6e  
{ QA)"3g   
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]gF=I5jn]  
} D5].^*
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~XvMiWuo  
//线程睡眠 "-AFWWKtx  
public static void sleep(int nSecond) 1|>bG#|  
{ f9IqcCSW  
try{ Gc5mR9pV   
Thread.sleep(nSecond); g?Rq .py]!  
} MU:v& sk  
catch(Exception e) hgwS_L  
{ /Bk`3~]E>  
e.printStackTrace (); EQM[!g^a  
} 98uMD  
} w_LkS/  

#G?",,&dM  
//日志 _G/uDP%  
public static void log(String sMsg) +@7c:CAy(  
{ !ZCxi  
System.err.println(sMsg); bX5/xf$q  
} /len8FRf  
beV+3HqB8  
DiZv sc  
public static void log(int sMsg) #!_ViG )2^  
{ ="Azg8W  
System.err.println(sMsg); <A`S
C;k\u  
} km`";gUp>  
} Pi,86?  
iuM ,aF  
rsw=a_S  
/* x8wsx F  
**TestMethod.java w^7[4u4  
*/ X76rme  
package NetFox; _6]CT0  
-&)  
,ZO?D|M1  
public class TestMethod { XB:E<I'q!3  
4s"x}c">F  
' 8Q}pp`  
public TestMethod() NpbZt;%t  
{ ///xx/weblogic60b2_win.exe fl4'dv  
try{ =vDDfPR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Z]5xy_La  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #H5+8W  
SiteFileFetch fileFetch = new SiteFileFetch(bean); aqQ  U7  
fileFetch.start(); 8k.#4}fP  
} 3-[+g}kak?  
catch(Exception e){e.printStackTrace ();} 1&Mpx!K*T  
58`Dcx,yJ  
%/_E8GE  
} +vV?[e  
0[8uuqV[cB  
<u?\%iJ"  
public static void main(String[] args) 6\y?+H1  
{ 'I>geW?{QK  
new TestMethod(); OL@
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} {"rL3Lk  
} [8 23w.{]#  
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