http断点续传简单实现（java)

/* B9#;-QO  
**SiteFileFetch.java %{'4. ,  
*/ qqvF-mDN  
package NetFox; A[JM4x   
import java.io.*; ir&.Z5=  
import java.net.*; "DpKrVuG  
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public class SiteFileFetch extends Thread { ,LUTHWEo"I  
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SiteInfoBean siteInfoBean = null; //文件信息Bean j^EbO3  
long[] nStartPos; //开始位置 qm%nIU \*  
long[] nEndPos; //结束位置 m~>@BCn
;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [W;[v<E;  
long nFileLength; //文件长度 ^
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boolean bFirst = true; //是否第一次取文件 uJ8{HB  
boolean bStop = false; //停止标志 nk/vGa4
  
File tmpFile; //文件下载的临时信息 D=&K&6rr  
DataOutputStream output; //输出到文件的输出流 (/?R9T[V&^  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (>AFyh&3,X  
public SiteFileFetch(SiteInfoBean bean) throws IOException Dbz]{_Y;  
{ 3
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siteInfoBean = bean; X| <yq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fj+O'X  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); i0ybJOa4  
if(tmpFile.exists ()) LNiS`o\  
{ a.,_4;'UE1  
bFirst = false; +)gB9DoK  
read_nPos(); O-!,Jm   
} I7G,`h+H  
else xZ+]QDKC  
{ _B$"e[:yX  
nStartPos = new long[bean.getNSplitter()]; =bL{i&&  
nEndPos = new long[bean.getNSplitter()]; . #U}q 7X  
} 0p3vE,pF  
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Q  
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} zH=hIVc  
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public void run() K\^&+7&zVg  
{ ipZHSA  
//获得文件长度 9,WG!4:+W  
//分割文件 @]?R2bI  
//实例FileSplitterFetch aU(tu2  
//启动FileSplitterFetch线程 Z*eoA  
//等待子线程返回 r0btC@Hxy  
try{ YoAg  
if(bFirst) f:vD`Fz1  
{ RIjM(P  
nFileLength = getFileSize(); D]u=PqHk2  
if(nFileLength == -1) /b{HG7i\  
{ [`n
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System.err.println("File Length is not known!");
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} fSI%c3  
else if(nFileLength == -2) * nCx[  
{ 9L HuS  
System.err.println("File is not access!"); eP= j.$  
} _}ele+  
else {D,RU8&  
{ V(..8}LlD  
for(int i=0;i<nStartPos.length;i++) E}$V2ha0zu  
{ x6e+7"#~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %U?)?iZdL  
} 7\%$>< K  
for(int i=0;i<nEndPos.length-1;i++) ]o*$h$?s  
{ )4ncutb  
nEndPos = nStartPos[i+1]; CZ tiWZ  
} M/B/b<['  
nEndPos[nEndPos.length-1] = nFileLength; &+- e  
} v#Upw\!  
} 2AK}D%jfc  
#r}uin*jD  
kqf8=y  
//启动子线程 m6MaX}&zv  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6~@5X}^<0  
for(int i=0;i<nStartPos.length;i++) usH%dzKK  
{ ]l&'k23~p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o#}mkE87  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \ V?I+Gc  
nStartPos,nEndPos,i); +-ewE-:|L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z!Hx @){|  
fileSplitterFetch.start(); 8ds}+TtbY  
} 5hz_P+Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8\_*1h40s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vgAFuQi(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5/(sjMB  
nEndPos = " + nFileLength); XhA4:t  
// fileSplitterFetch[nPos.length-1].start(); sam[s4@eQ  
F*\4l;NJ  
[*HiI=  
//等待子线程结束 ZIW7_Y>_  
//int count = 0; K~@`o-Z[  
//是否结束while循环 O6]u!NqG  
boolean breakWhile = false; ]_#SAhOR)  
{AgBwBCE  
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while(!bStop) !gJzg*{u@  
{ ]-Lruq#  
write_nPos(); }!B.K^@)  
Utility.sleep(500); y5%5O xB  
breakWhile = true; m1y `v"  
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for(int i=0;i<nStartPos.length;i++) ?i%nMlcc  
{ b
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if(!fileSplitterFetch.bDownOver) AY;<q$8j%,  
{ zq=&4afOE  
breakWhile = false; t= *Jg/$  
break; Hz?,#>{
  
} y/\ZAtnLo  
} ;sQ20 B'  
if(breakWhile) pN+I]NgQ  
break; _yJ|`g]U3  
-( Kh.h  
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//count++; ~'{VaYk]v  
//if(count>4) |*1xrM:v~  
// siteStop(); r\RFDj  
} >#?iO]).  
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System.err.println("文件下载结束！"); 5p{25N_t  
} #G~wE*VR$  
catch(Exception e){e.printStackTrace ();} C*Xik9n  
} vX 1W@s  
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//获得文件长度 UOJ*a1BM  
public long getFileSize() kwc*is  
{ <(?' s9  
int nFileLength = -1; oN ;-M-(  
try{ )@,N7Y1h  
URL url = new URL(siteInfoBean.getSSiteURL()); IywiCMjH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )r#,ML  
httpConnection.setRequestProperty("User-Agent","NetFox"); hpas'H>J  
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int responseCode=httpConnection.getResponseCode(); jm+blB^%K  
if(responseCode>=400) Bs@:rhDi  
{ A$ J9U3+O  
processErrorCode(responseCode); y
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return -2; //-2 represent access is error ?
-S8yqe  
} wA1Ey:q  
0}D-KvjyP  
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String sHeader; []=_<]{   
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}1,'rmT
 
for(int i=1;;i++) FvAbh]/4  
{ s!aO*\[<h  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3l$E8?[Zwi  
//Utility.log(in.readLine()); y,V6h*x2  
sHeader=httpConnection.getHeaderFieldKey(i); 9u?Eb~#$  
if(sHeader!=null) VZTmzIk.Y  
{ X'xUwT|_+  
if(sHeader.equals("Content-Length")) l[Tt[n  
{ @wMQC\Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |SxMN%M
!  
break; %fBP:5%K  
} ]d^k4 d  
} V&g)m.d:n  
else TqXge{r  
break; W oWBs)E  
} FN>L7 *,0  
} <c(&T<$  
catch(IOException e){e.printStackTrace ();} _TrZ'iL}T  
catch(Exception e){e.printStackTrace ();} N6WPTUQ1mF  
}a'cm!"  

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Utility.log(nFileLength); )O9fhj)  
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return nFileLength; X:U=MWc>  
} }\>+H  
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*!i,?vn  
//保存下载信息（文件指针位置） %n4@[fG%K  
private void write_nPos() 5`{=`  
{ r1+c/;TpZ  
try{ 9uKOR7.zbo  
output = new DataOutputStream(new FileOutputStream(tmpFile)); k{_1r;  
output.writeInt(nStartPos.length); 0u>yT?jP  
for(int i=0;i<nStartPos.length;i++) ftxTX3X  
{ z}iSq$  
// output.writeLong(nPos); lx`q *&E  
output.writeLong(fileSplitterFetch.nStartPos); 7:z>+AM[r  
output.writeLong(fileSplitterFetch.nEndPos); ' 4,y  
} hN[X 1*  
output.close(); d3og?{i<}&  
} Gl.?U;4
Z  
catch(IOException e){e.printStackTrace ();} 8~;{xYN )  
catch(Exception e){e.printStackTrace ();} A
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} 7,f:Qi@g  
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//读取保存的下载信息（文件指针位置） 4C6=77Jr  
private void read_nPos() =Y/}b\9`T  
{ &ycjSBK  
try{ 0T(O'v}.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !X%S)VSMU  
int nCount = input.readInt(); ZTr:xX{R6  
nStartPos = new long[nCount]; (Z5q&#f  
nEndPos = new long[nCount]; [?A&xqO3  
for(int i=0;i<nStartPos.length;i++) [TP  
{ Pb0)HlLq  
nStartPos = input.readLong(); tp7oc_s?.  
nEndPos = input.readLong(); L^6"'#  
} 1X[73  
input.close(); 6BUBk>A`  
} zMbfV%b  
catch(IOException e){e.printStackTrace ();} uFz/PDOZ@  
catch(Exception e){e.printStackTrace ();} JvKO $^  
} fdN45in=>  
"&@gX_%  
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private void processErrorCode(int nErrorCode) d
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{ Rk}\)r\  
System.err.println("Error Code : " + nErrorCode); MgHOj  
} mluW=fE  
p 7 ,f6kG  
3gC\{y!8  
//停止文件下载 ]gH wfqx  
public void siteStop() TViBCed40  
{ {F<)z%^  
bStop = true; kZJt~}  
for(int i=0;i<nStartPos.length;i++) eH ;Wfs2f  
fileSplitterFetch.splitterStop(); f#*h^91x  
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} Ga]47pQ"F  
} u9esdOv  
//负责部分文件的抓取 `Q:de~+AM{  
**FileSplitterFetch.java ~&t!$  
*/ {k kAqJ  
package NetFox; i:C.8hmAE  
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import java.io.*; c$@`P  
import java.net.*; G%xb0%oi]%  
p^T&jE8])#  
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public class FileSplitterFetch extends Thread { ,.~ W  
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String sURL; //File URL TFAYVK~  
long nStartPos; //File Snippet Start Position ]\[m=0K  
long nEndPos; //File Snippet End Position -0{T
 
int nThreadID; //Thread's ID d1UVv
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boolean bDownOver = false; //Downing is over
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boolean bStop = false; //Stop identical n/ui<&(  
FileAccessI fileAccessI = null; //File Access interface {CW1t5$*  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <]Ij(+J;  
{ O]c=Yyl  
this.sURL = sURL; h=uiC&B  
this.nStartPos = nStart; _cW_u?0X:  
this.nEndPos = nEnd; :Tlf4y:/w  
nThreadID = id; b{Z^)u2X  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 AQE eIFH  
} *!._Ais,\  
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;  
}rO?5  
public void run() yTzY?  
{ q>Q:X3  
while(nStartPos < nEndPos && !bStop) @WhZx*1  
{ <8}KEe4  
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try{ ;b, -$A  
URL url = new URL(sURL); 'CP/ymf/a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mle_*Gy8  
httpConnection.setRequestProperty("User-Agent","NetFox"); LEYWH%y  
String sProperty = "bytes="+nStartPos+"-"; %1Vu=zCAW  
httpConnection.setRequestProperty("RANGE",sProperty); v[0DE*p  
Utility.log(sProperty); E"Ya-8d=  
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InputStream input = httpConnection.getInputStream(); #Tr;JAzVjG  
//logResponseHead(httpConnection); ygmv_YLjm  
#pS]k<o%1  
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byte[] b = new byte[1024]; +")qi=
 
int nRead; {DKXn`V  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F{#N6,T  
{ !yoSMI-  
nStartPos += fileAccessI.write(b,0,nRead); 8[6ny=S`  
//if(nThreadID == 1) 7
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bBkm] 
>  
} !!?+M @  
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Utility.log("Thread " + nThreadID + " is over!"); >yV)d/  
bDownOver = true; T0@](g  
//nPos = fileAccessI.write (b,0,nRead); Nrab*K(][  
}  ET >S  
catch(Exception e){e.printStackTrace ();} [@,OG-"&  
} />dB%*  
} tc+GR?-7W  
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//打印回应的头信息 3::3r}g  
public void logResponseHead(HttpURLConnection con) -/(DPx  
{ !Iw{Y'  
for(int i=1;;i++) {]t\`fjrg  
{ LK'S)Jk  
String header=con.getHeaderFieldKey(i); p)?qJ2c|  
if(header!=null) K7t&fDI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); mF6@Y[/B  
Utility.log(header+" : "+con.getHeaderField(header)); ua]\xBWx  
else e5*5.AB6&  
break; %JP&ox|^&  
} no~OR Q  
} `^ieT#(O  
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public void splitterStop() A}>|tm7|  
{ )64LKb$  
bStop = true; t*Z .e.q+  
} kPx]u\  
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} KKeb ioW  
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/* C:'WX*W  
**FileAccess.java ]p4`7@@)*  
*//文件访问(定位，写) <GL}1W"Ay  
package NetFox; ql#{=oGDnA  
import java.io.*; >,w
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d&PE,$XC  
public class FileAccessI implements Serializable{ 1S*8v7  
"4Vi=*2V  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p6&LZ=tL3  
RandomAccessFile oSavedFile; hYP6z^  
long nPos; h/0<:eZ*  
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public FileAccessI() throws IOException rE1np^z7  
{ cM> G>Yzo  
this("",0); ! /|0:QQi  
} 
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Ct =E;v7}  
public FileAccessI(String sName,long nPos) throws IOException _Ep{|]:gw  
{ ~>}dse  
oSavedFile = new RandomAccessFile(sName,"rw"); tMD^$E"C  
this.nPos = nPos; U<ku_(2"#  
oSavedFile.seek(nPos); -dc5D@4`#s  
} Q{H!s_6iyv  
~.PPf/ Z8]  
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public synchronized int write(byte[] b,int nStart,int nLen) ~cO?S2!W  
{ 9}%~w(P  
int n = -1; |kBg8)
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try{ r
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oSavedFile.write(b,nStart,nLen); _g^K$+F'}  
n = nLen; CI~hmL0  
} wS F!Xx0  
catch(IOException e) ~_dBND?  
{ G<">/_jn  
e.printStackTrace (); z{D$~ ob  
} G:h;C].  
2g ?Jb5)  
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return n;  ?;ALF  
} 7})!>p )  
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} MYDf`0{$_a  
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/* 0]:*v?  
**SiteInfoBean.java J-eA,9J  
*/ WQIM2_=M  
package NetFox; J]=aI>Ow  
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public class SiteInfoBean { T(sG.%  
1eE]4Z4Q  
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private String sSiteURL; //Site's URL ySr091Q  
private String sFilePath; //Saved File's Path m 1'&{O:  
private String sFileName; //Saved File's Name K*HVn2OV  
private int nSplitter; //Count of Splited Downloading File &|'Kut?8  
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public SiteInfoBean() PoBukOv  
{//nSplitter的缺省值为5 NR;S3-Iq(  
//default value of nSplitter is 5 G(7\
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this("","","",5); o3TBRn,  
} FM;;x(sg  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) eBSn1n  
{ k<j)?_=`  
sSiteURL= sURL; T|BY00Sz`  
sFilePath = sPath; jziA;6uL  
sFileName = sName; 1v[#::Bs  
this.nSplitter = nSpiltter; _Sk<S  
\J3v>&m<7  
8,H#t@+MT  
} ^)C$8:@  
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public String getSSiteURL()  4s1kZ`e  
{ P5 <85t  
return sSiteURL; wNf*/?N  
} g`~lIt[=  
t;e]L'z@:  
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public void setSSiteURL(String value) yNWbI0a  
{ RqX4ep5j  
sSiteURL = value; 6M<mOhp@}n  
} N8L)KgM5#7  
V"2AN3~&  
[hv3o0".  
public String getSFilePath() zhR_qW+  
{ 6Ymo%OT  
return sFilePath; V)?x*R*T)  
} #:ED 0</  
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public void setSFilePath(String value) qI V`zZc  
{ 2)I'5
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sFilePath = value; G.q^Zd#.T  
} v;F+fOo  
p-(ADQS  
9^Vx*KVrU  
public String getSFileName() d@>k\6%j  
{ a,0o{*(u$  
return sFileName; ?w5nKpG#RI  
} )Ido|!]0d  
si mX  
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public void setSFileName(String value) `aWwF} +Y  
{ *V@MAt  
sFileName = value; g9lg  
} E*T84Jh6  
T=f;n;/>  
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public int getNSplitter() @SQ*/sw (c  
{ Fp|rMq
 
return nSplitter; uTlT'9)  
} Bdk{.oh6  
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;~1/eF  
public void setNSplitter(int nCount) @Ozf}}#  
{ yV]-Oa$*s0  
nSplitter = nCount; zC>(!fJq
q  
} S,<.!v57  
} CK`3   
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/* %Ty {1'o  
**Utility.java fdH'z:Xao  
*/ v8fZ?dx  
package NetFox; pt|$bU7  
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public class Utility { PA-0FlV|  
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public Utility() HOQ _T4  
{ :~A1Ud4c  
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3<'Q`H>  
} 3L!&~'.Ro  
nTtt$I@hW  
//线程睡眠 yI|?iBc7nC  
public static void sleep(int nSecond) vheAh`u^&  
{ OFAqP1o{$  
try{ q2U"k  
Thread.sleep(nSecond); R^O)fL0_  
} LAVt/TcZS|  
catch(Exception e) 2'^OtM,  
{ N4]6LA6x6  
e.printStackTrace (); _.8]7f`*Gc  
} PH4bM  
} Qs[EA_  
om39;nk!}  
//日志 N*oJ$:#  
public static void log(String sMsg) p
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{ wa
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System.err.println(sMsg); mE@o
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} /g-X=|?F  
GDQg:MgX  
2uR4~XjF  
public static void log(int sMsg) ]~ 8N  
{ <.B> LU  
System.err.println(sMsg); mt]YY<l  
} wU3ica&[   
} 5OqsnL_V  
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PaI63 !  
/* o|n0?bThS-  
**TestMethod.java LUVJ218p  
*/ {rJF)\2  
package NetFox; &$Ip$"H  
2<./HH*f  
;}9Ws6#XQs  
public class TestMethod { >;U%~yy}qc  
q9z!g/,d/  
zyn =Xv@p  
public TestMethod() {[y"]_B4  
{ ///xx/weblogic60b2_win.exe w3|.4hS  
try{ hfa_M[#Q-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ' g!_Flk  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); NP`ll0s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?B:wV?-`  
fileFetch.start(); {
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} NbMH@6%E  
catch(Exception e){e.printStackTrace ();} %.gjBI=  
7n/I'r  
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} t4W0~7  
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&`y_R'  
public static void main(String[] args) {YLJKu!M  
{ p.Yg-CA  
new TestMethod(); _BaS\U%1(  
} n/Z =q?_  
} 0~5}F^8[L  
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