http断点续传简单实现（java)

/* Znb7OF^#"  
**SiteFileFetch.java Ve|:k5z  
*/ 9/29>K_  
package NetFox; PjEJC@n  
import java.io.*; .gDq+~r8O  
import java.net.*; $Q8 &TM}E  
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public class SiteFileFetch extends Thread { 9/{zS3h3  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \ m~?yq8H  
long[] nStartPos; //开始位置 Zf@B< m  
long[] nEndPos; //结束位置 30uPDDvar  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3._
ep  
long nFileLength; //文件长度 6 Ln~b<I  
boolean bFirst = true; //是否第一次取文件 T9Q3I  
boolean bStop = false; //停止标志 o=($'(1  
File tmpFile; //文件下载的临时信息 hA5')te<  
DataOutputStream output; //输出到文件的输出流 A\Ib  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +m%%Bz>  
public SiteFileFetch(SiteInfoBean bean) throws IOException Icrnu}pl_  
{ N7J?S~x  
siteInfoBean = bean; )xyjQ|b  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %r(WS_%K|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (?\+
  
if(tmpFile.exists ()) 5\bGCf  
{ R\3a Sx L  
bFirst = false; D;V[9E=g/  
read_nPos(); NUltuM  
} e9KD mX_  
else YP_
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{ X%5eZ"1{x  
nStartPos = new long[bean.getNSplitter()]; '^_u5Y]  
nEndPos = new long[bean.getNSplitter()]; 7:
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} 1]2]l*&3  
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} U*$P"sS`  
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public void run() E@ U]k$M  
{ bJ!\eI
%ld  
//获得文件长度 X"r)zCP+t  
//分割文件 EYq?NL='  
//实例FileSplitterFetch [UzD3VPg  
//启动FileSplitterFetch线程 *pJGp:{6V?  
//等待子线程返回 *tF~CG$r  
try{ |^1U<'oM#  
if(bFirst) dyWp'vCQs\  
{ 4Lt9Dx1  
nFileLength = getFileSize(); 1^WGJ"1  
if(nFileLength == -1) )FQ"l{P  
{ @=VxWU  
System.err.println("File Length is not known!"); M-"j8:en  
} f"5O'QHGQK  
else if(nFileLength == -2) LN5LT'CE   
{ b]4dmc*N+  
System.err.println("File is not access!"); MJ)lZ!KZ  
} W%g*sc*+  
else I1E9E$m5\<  
{ .Az36wD  
for(int i=0;i<nStartPos.length;i++) E?XaU~cpc  
{ ! dzgi:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); c
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} "17)`Yf  
for(int i=0;i<nEndPos.length-1;i++) f)/Z7*Z  
{ I
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nEndPos = nStartPos[i+1]; 
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} VyxYv-$Y  
nEndPos[nEndPos.length-1] = nFileLength; /e'3\,2_  
} LW]fme<V?  
} Wm}c-GD  
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dM-cQo:  
//启动子线程 e,p"=/!aY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^&
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for(int i=0;i<nStartPos.length;i++) ,@ 8+%KqG  
{ SN{+ Pk  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iNA3Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C 5.3[  
nStartPos,nEndPos,i); lhN@,q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V*4Z.3/E5  
fileSplitterFetch.start(); &F&`y  
} =:WZV8@%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8v"rM >[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ebk>e*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", EU?qLj':  
nEndPos = " + nFileLength); {[oNUzcd  
// fileSplitterFetch[nPos.length-1].start(); [A-_?#cZ  
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5CkG^9  
//等待子线程结束 K~ eak\=  
//int count = 0; D|LO!,=b  
//是否结束while循环 OM\J4"YV$  
boolean breakWhile = false; b{
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J6Z[c*W  
2Xt4Rqk$  
while(!bStop) @k?vbq  
{ QHk\Z  
write_nPos(); }e[ E  
Utility.sleep(500); x%B_v^^^  
breakWhile = true; ?Z#N9Z~\  
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for(int i=0;i<nStartPos.length;i++) &GP(yj]  
{ /s\ mV  
if(!fileSplitterFetch.bDownOver) g&Vhu8kNIA  
{ }Ce9R2  
breakWhile = false; 7OV^>"S  
break; YJJ1N/Z1  
} fq7#rZCxX  
} "Oxr}^% i  
if(breakWhile) U: 9&0`k(  
break; ,MY7h8V/  
,-pE/3|(  
uBm"Xkxe|w  
//count++; f@OH~4FG  
//if(count>4) fzSkl`K}  
// siteStop(); Dp'urf\*$  
} BPY7O  
;KL7SM%g4  
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System.err.println("文件下载结束！"); E'QAsU8pP  
} 5 D|#l*V  
catch(Exception e){e.printStackTrace ();} I\@r~]+y  
} *QC6zJ  
7~h3B<  
h[ .  
//获得文件长度 \((iR>^|  
public long getFileSize() dfDjOZSL  
{ I5Vn#_q+b  
int nFileLength = -1; `0d0T~  
try{ BhJ>G%  
URL url = new URL(siteInfoBean.getSSiteURL()); ^h[6{F~J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1WUSp;JMl  
httpConnection.setRequestProperty("User-Agent","NetFox"); ZbFD|~[ V  
'oa.-g5  
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int responseCode=httpConnection.getResponseCode(); "Lp.*o  
if(responseCode>=400) wLV,E,gM  
{ ng1E'c]0@  
processErrorCode(responseCode); k<9,Ypa  
return -2; //-2 represent access is error "-4|HA  
} tr0b#4  
H,7='n7"  
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String sHeader; P3oYk_oW  
&[ })FI  
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for(int i=1;;i++) L!Jx`zM^  
{
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); e={O&9Z  
//Utility.log(in.readLine()); [OC(~b  
sHeader=httpConnection.getHeaderFieldKey(i); f1'ByV'2  
if(sHeader!=null) uyj!$}4  
{ 6#Vl3o(E|  
if(sHeader.equals("Content-Length")) &h5Vhzq(<  
{ 6{2y$'m8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); JYdb^j2c  
break; }+,Q&]>~  
} 1c$pz:$vX  
} BtJkvg(2]  
else l)u%`Hcn  
break; |IAx!Z-P  
} ?JuJu1  
} CsR[@&n'  
catch(IOException e){e.printStackTrace ();} ^twyy9VR  
catch(Exception e){e.printStackTrace ();} ^ D0"m>3r  
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Utility.log(nFileLength); <a R  
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return nFileLength; l6'KIg  
} @-q,%)?0}=  
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,N$Q']Td  
//保存下载信息（文件指针位置） d6i}xnmC  
private void write_nPos() EjPR
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{ *bK=<{d1P  
try{ #$WnMJ@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); u(9pRr L  
output.writeInt(nStartPos.length); +)c<s3OCE  
for(int i=0;i<nStartPos.length;i++) q;K]NP-_p  
{ (B#FLoK  
// output.writeLong(nPos); R@\fqNq  
output.writeLong(fileSplitterFetch.nStartPos); dle\}Sy=  
output.writeLong(fileSplitterFetch.nEndPos); gwaSgV$z  
} 4MC]s~n  
output.close(); KloX.
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} xW"O|x$6  
catch(IOException e){e.printStackTrace ();} 49FP&NgK  
catch(Exception e){e.printStackTrace ();} XDK Me}  
} _`2%)#^o  
:!i=g+e]  
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//读取保存的下载信息（文件指针位置） g~<[;6&{  
private void read_nPos() 1d<?K7%^  
{ 2a@X-Di  
try{ o[;P@F  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >MYxj}I4{z  
int nCount = input.readInt(); H{cOkuy  
nStartPos = new long[nCount]; FK BRJ5O  
nEndPos = new long[nCount]; bdrE2m  
for(int i=0;i<nStartPos.length;i++) <:-4GJH=  
{ zC*FeqFL<  
nStartPos = input.readLong(); DgEdV4@p  
nEndPos = input.readLong(); u>fs yn9c  
} 6*,55,y  
input.close(); UP#@gxF  
} Uz;^R@  
catch(IOException e){e.printStackTrace ();} Q<>u)%92@  
catch(Exception e){e.printStackTrace ();} imOIO[<;  
} / Xnq0hN  
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private void processErrorCode(int nErrorCode) 091m$~r*  
{ 5bb#{?2i  
System.err.println("Error Code : " + nErrorCode); oyVT  
} *twGIX
 
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|QS|\8g{0V  
//停止文件下载 \d
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public void siteStop() '@t,G,FJ  
{ sm##owI  
bStop = true; qiOtbH=  
for(int i=0;i<nStartPos.length;i++) %LnLB  
fileSplitterFetch.splitterStop(); >V.?XZ nt  
/5 z+N(RFC  
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} ,u@:(G  
} Lginps[la  
//负责部分文件的抓取 lLQcyi0  
**FileSplitterFetch.java tDETRjTA  
*/ @<DRFP  
package NetFox; :%sG'_d  
9>{ml&$  
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import java.io.*; .i\FK@2  
import java.net.*; j&ti "|2\  
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public class FileSplitterFetch extends Thread { 39^+;Mev  
)EMlGM'2q  
{"jtR<{)  
String sURL; //File URL l_k:OZ  
long nStartPos; //File Snippet Start Position  XY)X-K$  
long nEndPos; //File Snippet End Position Q'U!  
int nThreadID; //Thread's ID a[;
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boolean bDownOver = false; //Downing is over 
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boolean bStop = false; //Stop identical AXcmN  
FileAccessI fileAccessI = null; //File Access interface mBIksts5h  
P^o@x,V!&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ttr`  
{ &SIf|IX.  
this.sURL = sURL; e!Z}aOeE  
this.nStartPos = nStart; g)f& mQ)  
this.nEndPos = nEnd; [Zdrm:=]L  
nThreadID = id; \<I&utn  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :V$\y up  
} GX23c i  
="G2I\  
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public void run() i&(1<S>P  
{ K1YxF  
while(nStartPos < nEndPos && !bStop) jNbVp{%/S}  
{ h5P ]`r  
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try{ 62;xK-U  
URL url = new URL(sURL); L=54uCv Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u ^#UsOt+  
httpConnection.setRequestProperty("User-Agent","NetFox"); %i7U+v(d  
String sProperty = "bytes="+nStartPos+"-"; #n&/v'!\  
httpConnection.setRequestProperty("RANGE",sProperty); y?cN  
Utility.log(sProperty); 0.m-}  
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InputStream input = httpConnection.getInputStream(); ,g'>
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//logResponseHead(httpConnection); [qY yr
  
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byte[] b = new byte[1024]; xA^E+f:W_  
int nRead; yC ?p,Ci,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  G>?kskm  
{ V~jp  
nStartPos += fileAccessI.write(b,0,nRead); C-ORI}o  
//if(nThreadID == 1) dU_;2d$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FD!8
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} +hKU]DP2;  
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Utility.log("Thread " + nThreadID + " is over!"); ]Ndy12,M  
bDownOver = true; S~r75] "  
//nPos = fileAccessI.write (b,0,nRead); ].Bx"L!B  
} NHUJ:j@  
catch(Exception e){e.printStackTrace ();} 1mHS -oI9J  
} f4,|D |  
} pC,Z=+:  
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//打印回应的头信息 k)z>9z%D  
public void logResponseHead(HttpURLConnection con) ;jx[ +  
{ 8wO4;  
for(int i=1;;i++) vr"Pr4z4i  
{ k:7Gb7\  
String header=con.getHeaderFieldKey(i); a:GM|X  
if(header!=null) Q
m7];,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Uufig)6  
Utility.log(header+" : "+con.getHeaderField(header)); ?zP 2   
else W=g'Xu!|!2  
break; vC1fKo\p  
} \^pc"?Rc  
} izcjI.3e,  
[QMN0#(h  
@x*xgf  
public void splitterStop() {m3#1iV9  
{ Y6Y"fb%K  
bStop = true; C(h<s e?  
} i@D4bd9lR  
#?\(l%  
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} |_g7k2oLY  
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/* ]5@n`;&#.  
**FileAccess.java OpazWcMoo  
*//文件访问(定位，写) +VQD'  
package NetFox; :Hb`vH3x  
import java.io.*; QoUdTIIL  
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g-!  
public class FileAccessI implements Serializable{ MBjAe!,-  
w*~s&7c2B  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `#<UsU,~Lu  
RandomAccessFile oSavedFile; |RD)pvVM  
long nPos; R#YeE`K  
9D`K#3}  
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public FileAccessI() throws IOException SAitufS  
{ 7l/ZRz}1  
this("",0); p<\!{5:  
} &N=vs  
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public FileAccessI(String sName,long nPos) throws IOException hP'4PLK  
{ Tc"J(GWG  
oSavedFile = new RandomAccessFile(sName,"rw"); 7vRp<  
this.nPos = nPos; wC%qSy'  
oSavedFile.seek(nPos); nC[aEZ7  
} /9gn)q2f(  
8PVjNS/  
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public synchronized int write(byte[] b,int nStart,int nLen) f34/whD65  
{ (f_YgQEL  
int n = -1; | @ ut/  
try{ .9Cy<z  
oSavedFile.write(b,nStart,nLen); ?[.8A/:5  
n = nLen; Y+),c14#  
} C+M]"{Y+  
catch(IOException e) zx$1.IM"4  
{ du~V=%9  
e.printStackTrace (); h*40jZ  
} 4sORp^t'Q  
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return n; Nr]Fh  
} $kN=45SR  
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} !"yr;t>|Zb  
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,W[J@4.  
/* ?Be}{Qqlg  
**SiteInfoBean.java
aaKf4}  
*/ 7q;`~tbC  
package NetFox; m44a HBwId  
EAXl.Y. $  
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public class SiteInfoBean { ^Lc\{,m  
_[E+D0A  

1|w@f&W"  
private String sSiteURL; //Site's URL ORF:~5[YS`  
private String sFilePath; //Saved File's Path +ansN~3  
private String sFileName; //Saved File's Name =+mb@#="m  
private int nSplitter; //Count of Splited Downloading File uJH[C>  
\X\f~CB  
| ?vm.zp  
public SiteInfoBean() eC%Skw  
{//nSplitter的缺省值为5 Z- a
  
//default value of nSplitter is 5 Djc-f  
this("","","",5); vK+reXE  
} A-uIZ zC  
LWTPNp:"{w  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) flC%<V
%'-  
{ =&pLlG
  
sSiteURL= sURL; Xj{fM\,"9  
sFilePath = sPath; (57!{[J  
sFileName = sName; [|c%<|d2  
this.nSplitter = nSpiltter; pw4^E|X  
itirh"[  
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} 1d FuoX  
8 I_  
<,GVrVH=t"  
public String getSSiteURL() 3Ji$igL  
{ g6lWc@]F  
return sSiteURL; AnX<\7bc}  
} ZfqN4  
ARf{hiV6Wt  
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public void setSSiteURL(String value) UQ0<sI=  
{ 7XyCl&Dc:  
sSiteURL = value; X|Y(*$?D7  
} _ pz}  
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^s7!F.OC  
public String getSFilePath() ,I5SAd|dX  
{ EV{Ys}3M  
return sFilePath; OrM1eP"I  
} 54z.@BJhE  
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!*"fWahv  
public void setSFilePath(String value) aif;h! ?y  
{ 
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sFilePath = value; a=j'G]=  
} u)<s*jk  
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7>j~;p{  
public String getSFileName() 5a_8`csu  
{ CKK}Z;~:  
return sFileName; ]r|oNGD)G  
} :[
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1 rhZlmf[r  
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public void setSFileName(String value) }}tbOD)t  
{ < z2wt  
sFileName = value; A)C)5W  
} @lE'D":?  
/ }$n_N\!)  
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public int getNSplitter() ,n8\y9{
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{ sNo8o1Hby  
return nSplitter; i}DS+~8v  
} [A,^F0:h  
@pYEzizP7  
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public void setNSplitter(int nCount) 'v V7@@  
{ pCh v;  
nSplitter = nCount; Wvr{l  
} s b;q)Rh  
} \$wkr  
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n  
&R%'s1]o  
/* W/ Q*NB  
**Utility.java byM-$l  
*/ ]c7X~y  
package NetFox; g5@g_~ g  
GcdJf/k  
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public class Utility { HTOr  
&2`p#riAS  
(\{k-2t*^  
public Utility() /qX?ca1_4^  
{ 'V]&X.=zC  
_
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} ;[Mvk6^'R  
9KXL6#h  
//线程睡眠 8XB[CbO  
public static void sleep(int nSecond) ^'V :T Y  
{ rKrHd  
try{ f 5v&4  
Thread.sleep(nSecond); ?@.v*'qR  
} Jo\P,-\(  
catch(Exception e) h<Aq|*  
{ ai/|qYf  
e.printStackTrace (); _?I{>:!|  
} cl%+m  
} C}RO'_Pq  
3x0t[{l  
//日志 IFp%Ta  
public static void log(String sMsg) {6zNCO  
{ 5 aA* ~\  
System.err.println(sMsg); hGz_F/  
} Kp`{-dUf  
5.9<g>C  
u S1O-Q>  
public static void log(int sMsg) kyJbV[o<#  
{ "Wwu Ty|  
System.err.println(sMsg); p%3z*2,(  
} At iUTA  
} !@=S,Vc.  
Cq\XLh `  
} a9Ah:.7/  
/* R c+olJ^5  
**TestMethod.java T-e
n|.  
*/ ^viabkf C  
package NetFox; _p-e)J$7  
_B0(1(M<2  
\wK&wRn)  
public class TestMethod { f"ndLX:'}  
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{]T?)!Vm  
public TestMethod() @Vre)OrN#  
{ ///xx/weblogic60b2_win.exe 0<uek  
try{ Ek_5
% n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Wo1xZZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4dX{an]Cz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); X7},|cmD_  
fileFetch.start(); mM,HMrgLqK  
} q>$MqKWM  
catch(Exception e){e.printStackTrace ();} 51jgx,-|$  
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X4 Arn,  
} AE0uBv  
r)*23&Ojs  
94"+l@K  
public static void main(String[] args) .AfZ5s]/F  
{ cFUD$mp  
new TestMethod(); &lQ%;)
'  
} 'ToE Y3  
} 4)S99|1  
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