http断点续传简单实现（java)

/* pwFU2}I  
**SiteFileFetch.java })
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*/ q:Y6fbt<7  
package NetFox; CYPazOfj  
import java.io.*; 2ec$xms  
import java.net.*; tLD~  
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A$%Q4jC}  
public class SiteFileFetch extends Thread { ]DC;+;8Jc  
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SiteInfoBean siteInfoBean = null; //文件信息Bean i<4>\nc  
long[] nStartPos; //开始位置 pKt-R07*  
long[] nEndPos; //结束位置 :M22P`:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 fJ)N:q`  
long nFileLength; //文件长度 o~v_PD[S  
boolean bFirst = true; //是否第一次取文件 lX98"}  
boolean bStop = false; //停止标志 Y{k>*: Ax_  
File tmpFile; //文件下载的临时信息 HYjMNj0  
DataOutputStream output; //输出到文件的输出流 s;fVnaqG:  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） uFwU-LCe  
public SiteFileFetch(SiteInfoBean bean) throws IOException )\T@W  
{ ~Na=+}.q_  
siteInfoBean = bean; XYqpI/s  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); XJx,9trH  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2qZa9^}  
if(tmpFile.exists ()) E /fw?7eQ  
{ 4GG1E. z}  
bFirst = false;
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read_nPos(); \4h>2y  
} Ni2]6U  
else 9z5"y|$  
{ ,c4c@|Bh?  
nStartPos = new long[bean.getNSplitter()]; "El^38Ho  
nEndPos = new long[bean.getNSplitter()]; lpl8h4d  
} v!NB~"LQ  
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} 5/& 1Oxo  
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public void run() JN9^fR09G  
{ `9.dgV  
//获得文件长度 I2TD.wuIW  
//分割文件 1<xcMn0et  
//实例FileSplitterFetch [096CK  
//启动FileSplitterFetch线程 ]>tq|R78  
//等待子线程返回 ,f}h}  
try{ 3g4e']t  
if(bFirst) `1n
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{ [RAj3Fr0  
nFileLength = getFileSize(); P3'2IzNw  
if(nFileLength == -1) +"]oc{W!  
{ BJ~ivT<  
System.err.println("File Length is not known!"); puFXPw.3  
} +
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else if(nFileLength == -2) \,>_c  
{ QJx9I_  
System.err.println("File is not access!"); MV%Xhfk  
} )-=2w-ZX  
else {mNdL J  
{ y L*LJ  
for(int i=0;i<nStartPos.length;i++) \r)%R5_CQ  
{ 4\p$4Hs}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;aq`N}d  
} 7t'(`A6t/  
for(int i=0;i<nEndPos.length-1;i++) |q3f]T&+>{  
{ mO#I nTO  
nEndPos = nStartPos[i+1]; }l~]b3@qu  
} %$Aqbd  
nEndPos[nEndPos.length-1] = nFileLength; l`SK*Bm~<  
} "$GK.MP5  
} E@:Q 'g%  
:@.C4oq  
:~yzDk\I"-  
//启动子线程 @4;&hP2Z:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @gNpJB]V  
for(int i=0;i<nStartPos.length;i++) h~ $&  
{ 4[`[mE18.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {5>3;.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3 h#s([uL  
nStartPos,nEndPos,i); aiYo8+{!#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kEO1TS  
fileSplitterFetch.start(); _*Pfp+if  
} aC`Li^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IWQ&6SDW$z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Bb~5& @M|N  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", cn$5:%IK  
nEndPos = " + nFileLength); My. dD'C  
// fileSplitterFetch[nPos.length-1].start(); C1 W>/?XC  
.>P~uZiX!  
!~WZ_z  
//等待子线程结束 C5Xof|#p|  
//int count = 0; 't7Z] G  
//是否结束while循环 qk&gA}qF  
boolean breakWhile = false; [6H}/_nD  
b7bSTFZxC  
_ j~4+H  
while(!bStop) J==}QEhQ{  
{ -TgUyv.  
write_nPos(); ^\MhT)x  
Utility.sleep(500); Yt{ji  
breakWhile = true; 5:c;RRn  
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for(int i=0;i<nStartPos.length;i++) KGu= ;  
{ `qE4U4  
if(!fileSplitterFetch.bDownOver) qYiv   
{ +$PFHXB  
breakWhile = false; Mq@}snp"S  
break; S/VA~,KCe;  
} Q\|18wkW  
} NEMEY7De2  
if(breakWhile) HcA[QBh  
break; [<yz)<<  

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5C B%=iL{  
//count++; !3h{lEB  
//if(count>4) #7o0dE;Kg9  
// siteStop(); *<r%aeG$em  
} |CwG3&8  
YZ< NP  
7aQn;  
System.err.println("文件下载结束！"); zrrz<dW  
} :9`qogF>  
catch(Exception e){e.printStackTrace ();} 4`s)ue  
} Ir/:d]N*  
\#++s&06  
&U&Zo@ot"x  
//获得文件长度 (xL :;  
public long getFileSize() ailG./I+  
{ +#~O'r]%GG  
int nFileLength = -1; j{)~QD?  
try{ @ u+|=x];  
URL url = new URL(siteInfoBean.getSSiteURL()); ZOuR"9]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eQ<xp
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httpConnection.setRequestProperty("User-Agent","NetFox"); &Pq\cNYzW  
HyEa_9  
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int responseCode=httpConnection.getResponseCode(); LJWTSf"f?  
if(responseCode>=400) _dr*`yXi  
{ frc{>u~t  
processErrorCode(responseCode); E67XPvo1+@  
return -2; //-2 represent access is error E5gl^Q?Z  
} 7/?DPwbx  
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9 ZGV%Tw  
String sHeader; aM$=|
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for(int i=1;;i++) "U{,U`@?  
{ r1G8]agO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); oIb) Rq!m  
//Utility.log(in.readLine()); Y 9i][  
sHeader=httpConnection.getHeaderFieldKey(i); 0wFh%/:  
if(sHeader!=null) -L8YJ8J6  
{ D#jX6  
if(sHeader.equals("Content-Length")) y"-{$N  
{ b =b:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); RL*]g*  
break; TT7PQf >  
} (B:uc_+  
} {2:d`fqD  
else ]G*$W+G]  
break; DWrb
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} ]_u`EvEx6  
} Fg=v6j4W  
catch(IOException e){e.printStackTrace ();} o@3B(j;J`  
catch(Exception e){e.printStackTrace ();} /UHp [yod  
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Utility.log(nFileLength); gI{ =0  
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return nFileLength; 9|=nV|R'6  
} B\[-fq  
3gc"_C\
$  
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//保存下载信息（文件指针位置） :B.G)M\  
private void write_nPos() fhRjYYGI  
{ Q#pnj thM  
try{ h<% U["   
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~<,Sh~Ana.  
output.writeInt(nStartPos.length); C3}Aq8$6  
for(int i=0;i<nStartPos.length;i++) yp+F<5o  
{ iy
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// output.writeLong(nPos); r6t&E%b  
output.writeLong(fileSplitterFetch.nStartPos); X NE+(Bt  
output.writeLong(fileSplitterFetch.nEndPos); }0;Sk(B>  
} Z`s!dV]e9  
output.close(); )6{P8k4Zr  
} "w&/m}E,[  
catch(IOException e){e.printStackTrace ();} B< hEx@  
catch(Exception e){e.printStackTrace ();} gxmc|  
} S}cF0B1E*  
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//读取保存的下载信息（文件指针位置） m7m \`;  
private void read_nPos() tD-gc''H  
{ _wh
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try{ HO5d%85  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); G),db%,X2  
int nCount = input.readInt(); Yy h=G  
nStartPos = new long[nCount]; Hku=pr3Gn  
nEndPos = new long[nCount]; ZEGd4_ux  
for(int i=0;i<nStartPos.length;i++) 0d4cE10  
{ 85z;Zt
0{  
nStartPos = input.readLong(); Tpzw=bC^  
nEndPos = input.readLong(); wmYv
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} 31}W6l88c  
input.close(); Qra>}e%*
 
} &{W^W8,%  
catch(IOException e){e.printStackTrace ();} 4seciz0?  
catch(Exception e){e.printStackTrace ();} f#P_xn&et  
} -H\,2FO  
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private void processErrorCode(int nErrorCode) &fSTR-8ev#  
{ xl2g0?  
System.err.println("Error Code : " + nErrorCode); 1;Xgc@  
} S$O,] @)  
+(mL~td
01  
"HC)/)Mv@  
//停止文件下载 uT
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public void siteStop() @~o`#$*|  
{ 54q3R`y  
bStop = true; D{C:d\ e)$  
for(int i=0;i<nStartPos.length;i++) J^ ={}  
fileSplitterFetch.splitterStop(); ce'TYkPM  
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} 7Fl-(Nv`  
} kon=il<@  
//负责部分文件的抓取 Ei~f`{i  
**FileSplitterFetch.java 'qy#)F  
*/ 0x5xLg;Q  
package NetFox; o.^y1mH'  
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import java.io.*; XDYosC:  
import java.net.*; 4*M@]J "  
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public class FileSplitterFetch extends Thread { te'*<HM  
Y&~M7TYb  
s'L?;:)dyB  
String sURL; //File URL wPnybb{  
long nStartPos; //File Snippet Start Position B*,?C]0{  
long nEndPos; //File Snippet End Position y
 $V[_TN  
int nThreadID; //Thread's ID 2jA%[L9d^  
boolean bDownOver = false; //Downing is over (vQ+e
 
boolean bStop = false; //Stop identical <v$QM;Ff  
FileAccessI fileAccessI = null; //File Access interface J&6:d  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]W) jmw'mo  
{ \+Y!ILOI  
this.sURL = sURL; GDPo`#~  
this.nStartPos = nStart; FFe)e>bH  
this.nEndPos = nEnd; SLoo:)  
nThreadID = id; \FifzKA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 DJP6TFT&G  
} {$fsS&aPg  
@ls.&BHUP  
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public void run() EXpSh}  
{ *^h_z;{,  
while(nStartPos < nEndPos && !bStop) )}-
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{ @GGccF  
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try{ \9/1L?@  
URL url = new URL(sURL); /cY^]VLe  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~FUa:KYD  
httpConnection.setRequestProperty("User-Agent","NetFox"); k'+}9
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String sProperty = "bytes="+nStartPos+"-"; , Oli  
httpConnection.setRequestProperty("RANGE",sProperty); \0AiCMX[  
Utility.log(sProperty); -x'e+zT  
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InputStream input = httpConnection.getInputStream(); T:!MBWYe|  
//logResponseHead(httpConnection); 509Q0 [k  
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byte[] b = new byte[1024]; )saR0{e0N  
int nRead; tWD|qg_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9?`RR/w  
{ 'IQsve7cI  
nStartPos += fileAccessI.write(b,0,nRead); xb$yu.c  
//if(nThreadID == 1) yFM>T\@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OVswt  
} dZ2`{@AYY  
8$}OS-  
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Utility.log("Thread " + nThreadID + " is over!"); #*
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bDownOver = true; :oa9#
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//nPos = fileAccessI.write (b,0,nRead); (5`T+pAsV  
} N z~"vi(t  
catch(Exception e){e.printStackTrace ();} `WlE| G[  
} /f3m)pT  
} #`/QOTnm2c  
@{}rG8  
3jPB#%F  
//打印回应的头信息 >oqZ !V5[  
public void logResponseHead(HttpURLConnection con) |9,UaA  
{ t26ij`V  
for(int i=1;;i++) ;f%|3-q1[  
{ p&3> `C  
String header=con.getHeaderFieldKey(i); I/s.xk_i  
if(header!=null) P s#>y&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kO ![X^V  
Utility.log(header+" : "+con.getHeaderField(header)); R&So4},B  
else 3g'+0tEl  
break; a%K}j\M  
} )HVcG0H1  
} QIAR  
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public void splitterStop() |.w;r   
{ 8(A{;9^g  
bStop = true; uO'/|[`8  
} ,sDr9h/'C3  
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} $D_HZ"ytu  
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/* E`)Qs[?Gk  
**FileAccess.java dl
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*//文件访问(定位，写) :p-Y7CSSu  
package NetFox; iJP{|-h  
import java.io.*; Z"tQpJ
g  
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public class FileAccessI implements Serializable{ #
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\A(5;ZnuD  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #x~_`>mDN  
RandomAccessFile oSavedFile; _^T}_  
long nPos; yGEb7I$h  
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public FileAccessI() throws IOException D'L{wm  
{ #&siHHs \  
this("",0); ;.s:X  
} og-]tEWA1  
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8"M<{72U]  
public FileAccessI(String sName,long nPos) throws IOException CEqZ:c  
{ r~oSP^e'  
oSavedFile = new RandomAccessFile(sName,"rw"); ct0v$ct>f  
this.nPos = nPos; f z%tA39m  
oSavedFile.seek(nPos); KXe ka  
} ( V4G<-jG  
O5-;I,)H  
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public synchronized int write(byte[] b,int nStart,int nLen) 'F5)ACA%  
{  :]c=pH  
int n = -1; F<r4CHfh;  
try{ ]kS7n@8  
oSavedFile.write(b,nStart,nLen); q^Inb)FeN  
n = nLen; ]{Ek[Av  
} xIgql}.  
catch(IOException e) c]v +  
{ :6u~aT/  
e.printStackTrace (); kF-TG3  
} :`J>bHE  
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return n; hW%p#g;  
} FpzP#;  
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} *V|zx#RN  
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/* XS|mKuMcC  
**SiteInfoBean.java v3^t/[e~:  
*/ f)^t')  
package NetFox; "Ot{^_e  
MPvWCPB  

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public class SiteInfoBean { KjYDFrR4  
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}vD;DSz:  
private String sSiteURL; //Site's URL GP]TnQ<*;  
private String sFilePath; //Saved File's Path o+^Eu}[.  
private String sFileName; //Saved File's Name vYzVY\   
private int nSplitter; //Count of Splited Downloading File `M rBav  
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if@,vc  
public SiteInfoBean() /q*KO\L  
{//nSplitter的缺省值为5 ':sT
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//default value of nSplitter is 5 P)IjL&[  
this("","","",5); b~as64  
} .e$%[)D  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u]*5Ex(?  
{ ysVi3eq  
sSiteURL= sURL; w_H2gaQ  
sFilePath = sPath; s##Ay{  
sFileName = sName; ^ LbGH<#J  
this.nSplitter = nSpiltter; ohplj`X[21  
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} 0||F`24  
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public String getSSiteURL() A'~#9@l<  
{ %M6 c0d[9-  
return sSiteURL; C8MWIX}  
} jGiw96,Y  
4:`[qE3  
raHVkE{<  
public void setSSiteURL(String value) 2Oi'E  
{ Y^3)!>  
sSiteURL = value; $_bZA;EMQ  
} $rTu6(i1  
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5H
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public String getSFilePath() >[P%Ty);  
{ l/F!Bq[*g  
return sFilePath; -lnevrl   
} +"Ub/[J{G1  
+!xu{2!  
@<5Tba>SC  
public void setSFilePath(String value) sDAK\#z  
{ k}<<bm*f  
sFilePath = value; 2_N/wR#=&  
} w&C1=v -h  
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public String getSFileName() e&ts\0  
{ +9_,w bF  
return sFileName; '$*[SauAG  
} D&f!( n  
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public void setSFileName(String value) F-tFet  
{ dm 2EH  
sFileName = value; 9.]
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} `fMpV8vv  
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9R>~~~{-Go  
public int getNSplitter() r},lu=em  
{ !"%S#nrL$  
return nSplitter; vlAy!:CV  
} a_AJ)4  
2$Wo&Q^_  
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public void setNSplitter(int nCount) {yU0D*#6  
{ cTy'JT7  
nSplitter = nCount; =G*z 53  
} :i}@Br+R7L  
} D=JlA~tS>  
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+8eVj#N  
/* o Fi) d[`  
**Utility.java I<KCt2:X  
*/ ovSH}h!  
package NetFox; "G@E6{/  
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#XfT1  
public class Utility { Yq{jEatY{/  
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public Utility() Z) t{JHm:  
{ #:Xa'D+
 
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]
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} k3#wLJ  
yduuFK  
//线程睡眠 wZ O@J|  
public static void sleep(int nSecond) ^t7_3%%w  
{ 7<vy;"wB  
try{ !9PX\Xbn  
Thread.sleep(nSecond); *iYMX[$  
} ,,7.=#  
catch(Exception e) l*qk1H"g  
{ w~p4S+k&  
e.printStackTrace (); sc9]sIb  
} OFp#<o,p  
} $8=(I2&TW  
my]P_mE  
//日志 hj+p`e S  
public static void log(String sMsg) :Fc8S9  
{ N7a[B>+`  
System.err.println(sMsg); 51z/  
} 3#B@83C0Z  
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t={poQC~  
public static void log(int sMsg) +<z7ds{Z  
{ fs7~NY
 
System.err.println(sMsg); :ET x*c  
} 8pd&3G+  
} k~& o  
*XHj)DC;  
50COL66:7  
/* J#+Op/mmo  
**TestMethod.java *Q0lC1GQ  
*/ sFCf\y  
package NetFox; @}ZGY^  
+ 2O
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{({ R:!c  
public class TestMethod { !eV^Ah>PZ  
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4bE42c=Ca7  
public TestMethod() ]bf'  
{ ///xx/weblogic60b2_win.exe 7bHE!#L`0  
try{ =%xIjxYl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); O0->sR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "--/v. Cs  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *u58l(&`8  
fileFetch.start(); ]Kof sU_{  
} ykJ+%gla  
catch(Exception e){e.printStackTrace ();} .x]'eq}  
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av"Dljc  
} dP?nP(l  
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public static void main(String[] args) N!]PIWnC  
{ ,nI_8r"M>  
new TestMethod(); \A` gK\/h  
} :{
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} t$tsWAmiA[  
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