http断点续传简单实现（java)

/* X+LG Z4]D  
**SiteFileFetch.java vWpoaz/w  
*/ BfOQ/k))  
package NetFox; PTZ/jg@71  
import java.io.*; Z?"f#  
import java.net.*; 'PK;Fg\  
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public class SiteFileFetch extends Thread { >xB[k-C4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean TP R$oO2  
long[] nStartPos; //开始位置 f:hsE  
long[] nEndPos; //结束位置 wR]jJbF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 uzgQ_  
long nFileLength; //文件长度 JDp{d c  
boolean bFirst = true; //是否第一次取文件 yMVlTO  
boolean bStop = false; //停止标志 ;FfDi*S7  
File tmpFile; //文件下载的临时信息 3 jRI@  
DataOutputStream output; //输出到文件的输出流 mMSQW6~j  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） C(@#I7G  
public SiteFileFetch(SiteInfoBean bean) throws IOException mJN*DP{  
{ H.=S08c3kA  
siteInfoBean = bean; g*]/HS>e<G  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6)j4-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); hw9qnSeRy  
if(tmpFile.exists ()) 'h.:-1# L  
{ m(DJ6CSa  
bFirst = false; ;%W]b  
read_nPos(); YkuFt>U9,  
} 7G]v(ay  
else m]Gxep0%  
{ ewrs D'?  
nStartPos = new long[bean.getNSplitter()]; 4#"_E:;PQ  
nEndPos = new long[bean.getNSplitter()]; HY!R|  
} ky#5G-X  
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} ]o+5$L,5b  
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public void run() ~H4wsa39  
{ PXrv2q[5?  
//获得文件长度 /9@[gv A  
//分割文件 {i#z<ttu  
//实例FileSplitterFetch E>I\m!ue  
//启动FileSplitterFetch线程 )Bw}T  
//等待子线程返回 rZ#ZY  
try{ J1UG},-h  
if(bFirst) 50jZu'z:  
{ s{9G//  
nFileLength = getFileSize(); CR8szMa  
if(nFileLength == -1) eEl71  
{ scQnL'\  
System.err.println("File Length is not known!"); '^!#*O  
} 9,c_(%C  
else if(nFileLength == -2) +{h.nqdAE  
{ fPBJ%SZ  
System.err.println("File is not access!"); Uu_Es{@  
} !YVGT <  
else -~] q?k?  
{ A~)#  
for(int i=0;i<nStartPos.length;i++) PX/7:D?  
{ 
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); fK{m7?V  
} ^gSZzJ5  
for(int i=0;i<nEndPos.length-1;i++) $+  
{ i9koh3R\  
nEndPos = nStartPos[i+1]; C116c"  
} j@u]( nf  
nEndPos[nEndPos.length-1] = nFileLength; Ek6z[G` O  
} %5$)w;p.$'  
} 9y+0Zj+.  
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//启动子线程 L.?QZN%cN  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;V0^uB.z  
for(int i=0;i<nStartPos.length;i++) yQ!I`T>a  
{ <q.Q,_cW  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Us2IeR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >r\q6f#J4  
nStartPos,nEndPos,i); `F`{s`E)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c:I %j
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fileSplitterFetch.start();
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} \"pp-str  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /Os6i&;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A9_}RJ9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", JnIE6@g<y  
nEndPos = " + nFileLength); `n?Rxhkwp  
// fileSplitterFetch[nPos.length-1].start(); dt||nF  
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//等待子线程结束 [9^lAhX  
//int count = 0; ("KtJ  
//是否结束while循环 Bwl@Muw  
boolean breakWhile = false; '\M]$`Et  
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while(!bStop) fSF_O}kLp  
{ cDIZkni=  
write_nPos(); %#x l+^  
Utility.sleep(500); bRD-[)  
breakWhile = true; )uu(I5St  
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for(int i=0;i<nStartPos.length;i++) H<9_BA?  
{ H~ E<ek'~  
if(!fileSplitterFetch.bDownOver) %<0'xJ%%Q  
{
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breakWhile = false; q ;"/i*+3  
break; 7epil  
} UZpQ%~/  
} 3<)+)n  
if(breakWhile) Z 4QL&?U  
break; Ao+6^z_  
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//count++; \`;1[m  
//if(count>4) ;,/4Ry22j-  
// siteStop(); "H#pN;)+  
} ;pj,U!{%s\  
-}u1ZEND  
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System.err.println("文件下载结束！"); xzHb+1+p  
} )FN\jo!!.  
catch(Exception e){e.printStackTrace ();} z HT#bP:o  
} 2<9&OL  
Z!-V&H.
 
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//获得文件长度 y* :C~  
public long getFileSize() U@9v(TfV  
{ 3rBID  
int nFileLength = -1; <JIqkGeAi  
try{ $R%tD.d3  
URL url = new URL(siteInfoBean.getSSiteURL()); xXlx}C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `S+n,,l  
httpConnection.setRequestProperty("User-Agent","NetFox"); iJH?Z,Tjf  
g/frg(KF  
:{ iK 5  
int responseCode=httpConnection.getResponseCode(); NL,6<ZOon,  
if(responseCode>=400) _Q'f^Kj  
{ 0avtfQ +f  
processErrorCode(responseCode); zs6rd83#  
return -2; //-2 represent access is error PeIKx$$Kl{  
} OLo?=1&;;  
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String sHeader; jx{ fel  
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for(int i=1;;i++) 6LrI,d  
{ *R}p9;dpO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 31\mF\{V  
//Utility.log(in.readLine()); Z;S)GUG^  
sHeader=httpConnection.getHeaderFieldKey(i); d3\KUR^  
if(sHeader!=null) BiDyr  
{ |ZC'a!  
if(sHeader.equals("Content-Length")) O`$\Plt|v  
{ +koW3>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Lr9E02  
break; &dPUd~&EL  
} Yxy!&hPLv:  
} 9oIfSr
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else m%'T90mi  
break; :|8!w  
} Apj[z2nr  
} !1%Sf.`!_  
catch(IOException e){e.printStackTrace ();} I5)$M{#a  
catch(Exception e){e.printStackTrace ();} $&!|G-0'  
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Utility.log(nFileLength); ayh235>a(  
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return nFileLength; EEMRy  
} \GV'{W+o2  
;O|u`fAqT  
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//保存下载信息（文件指针位置） OsW*@v(  
private void write_nPos() 8 &v)Vi-  
{ d,o*{sM5d  
try{ 7kITssVHI  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~T/tk?:8Vi  
output.writeInt(nStartPos.length); P,b&

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for(int i=0;i<nStartPos.length;i++) .4l cES~  
{ ;VEKrVD  
// output.writeLong(nPos); EG|_YW7  
output.writeLong(fileSplitterFetch.nStartPos); Yg}b%u,Q  
output.writeLong(fileSplitterFetch.nEndPos); o^'QGs"  
} $d,/(*Y#-  
output.close(); pFV~1W:  
} kkW}:dBl  
catch(IOException e){e.printStackTrace ();} ^x$1N
f  
catch(Exception e){e.printStackTrace ();} ,B /b>i  
} \%9QE  
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//读取保存的下载信息（文件指针位置） .|Yn[?(  
private void read_nPos() +~*e B  
{ z_=V6MDM  
try{ )||CU]"b?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?*[35XUd  
int nCount = input.readInt(); g7lPQ_A*  
nStartPos = new long[nCount]; 4CtWEq  
nEndPos = new long[nCount]; yu
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for(int i=0;i<nStartPos.length;i++) fdHFSnQ g  
{ ~]`U)Aw  
nStartPos = input.readLong(); d(:I~m  
nEndPos = input.readLong(); kZ]pV=\Y*  
} ;@:-T/=  
input.close(); (Q&O'ng1  
} @6%7X7m  
catch(IOException e){e.printStackTrace ();} }$sTnea  
catch(Exception e){e.printStackTrace ();} mi7~(V>  
} KfYT  
6'x3g2C/  
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private void processErrorCode(int nErrorCode) Gm3`/!r  
{ =q|//*t2  
System.err.println("Error Code : " + nErrorCode); :Rnwyj])  
} 2[j`bYNe  
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//停止文件下载 -1~o~yGE  
public void siteStop() AX'-}5T=  
{ Ino]::ZJ/  
bStop = true; '1fyBU  
for(int i=0;i<nStartPos.length;i++) 6.$
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fileSplitterFetch.splitterStop(); .,U4 ATO  
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} [@B!N+P5;  
} A_e5Vb,u.  
//负责部分文件的抓取 EcSu[b  
**FileSplitterFetch.java 3xKgj5M  
*/ &Nw|(z&$  
package NetFox; bE@Eiac  
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import java.io.*; 8J
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import java.net.*; Z6Z/Y()4Tl  
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public class FileSplitterFetch extends Thread { yq<W+b/  
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String sURL; //File URL g:!R't?  
long nStartPos; //File Snippet Start Position $9xp@8b\_  
long nEndPos; //File Snippet End Position e.#,9  
int nThreadID; //Thread's ID Z}Q/u^Z  
boolean bDownOver = false; //Downing is over a;nYR5f  
boolean bStop = false; //Stop identical WTjmU=<\  
FileAccessI fileAccessI = null; //File Access interface vS[\j  
;Bw3@c  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9'(m"c_  
{ jGo\_O<of  
this.sURL = sURL; qn,fx6v4  
this.nStartPos = nStart; +x/vZXtOK  
this.nEndPos = nEnd; :#{0yno)H  
nThreadID = id; Iz;^D!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *J >6i2M,u  
} yF_/.mI  
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public void run() :S7[<SwL  
{ 57]La^#  
while(nStartPos < nEndPos && !bStop) 84i0h$Z
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{ &.#dZ}J  
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try{ hd[t&?{=  
URL url = new URL(sURL); }odjaM}5Nc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k,8^RI07@  
httpConnection.setRequestProperty("User-Agent","NetFox"); t]iKU@3  
String sProperty = "bytes="+nStartPos+"-"; }<w9Jfr"X  
httpConnection.setRequestProperty("RANGE",sProperty); %qqeL  
Utility.log(sProperty); tB4yj_ZF  
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InputStream input = httpConnection.getInputStream(); 3H4T*&9;n  
//logResponseHead(httpConnection); G `B=:s]  
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byte[] b = new byte[1024]; u6IM~kk>5  
int nRead; a40>_;}:x  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ae
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{ Z:V<P,N  
nStartPos += fileAccessI.write(b,0,nRead); $ 9E"{6;@  
//if(nThreadID == 1) hx/A215L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b^(
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} PL!dkaD^y>  
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Utility.log("Thread " + nThreadID + " is over!"); <1:I[b  
bDownOver = true; 4!-R&<TLve  
//nPos = fileAccessI.write (b,0,nRead); Z@$'fX?
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} `Hv"^o  
catch(Exception e){e.printStackTrace ();} i }Zz[b  
} !YlEXaS  
} x")Bmw$  
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e eyZ$n  
//打印回应的头信息
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public void logResponseHead(HttpURLConnection con) gp H@F
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{ H`Zg-j`  
for(int i=1;;i++) Bsd~_y}8  
{ %.Kr`#lCr  
String header=con.getHeaderFieldKey(i); 3/(eK%d4Xb  
if(header!=null) &_j<!3*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *YX:e@Fm.a  
Utility.log(header+" : "+con.getHeaderField(header)); U2~|AkL  
else X &G]ci  
break; BJLeE}=H  
} F&3:]1  
} -~H "zu`  
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public void splitterStop() g:p`.KuB  
{ BGOS(  
bStop = true; :Dtm+EQ  
} &NbSG
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} eu$"GbqY  
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/* {!wd5C@  
**FileAccess.java U7,.L  
*//文件访问(定位，写) IF<T{/MA  
package NetFox; |%3>i"Y@AK  
import java.io.*; 4$ah~E>,t  
LfCgvq6/pO  
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public class FileAccessI implements Serializable{ AI,E9  
300[2}Y]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9+.3GRt7  
RandomAccessFile oSavedFile; /c4$m3?]  
long nPos; p!<PRms@  
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public FileAccessI() throws IOException |V
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{ O
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this("",0); ]XL=S|tIq  
} C{G%"q  
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public FileAccessI(String sName,long nPos) throws IOException tn(6T^u  
{ lYr4gFOs  
oSavedFile = new RandomAccessFile(sName,"rw"); 9'|_1Q.b^  
this.nPos = nPos; J%!vhQ  
oSavedFile.seek(nPos); 9J<vkxG9`  
} jxYze/I  
1,we:rwX  
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public synchronized int write(byte[] b,int nStart,int nLen) u%OLXb  
{ #H5+8W  
int n = -1; 77]lpmC  
try{ tZ*>S]qD  
oSavedFile.write(b,nStart,nLen); lACS^(  
n = nLen; kn`O3cW/  
} #&z'?x^a  
catch(IOException e) $`lGPi(Jc  
{ R[m+s=+  
e.printStackTrace (); a\B?J  
} H6KBXMYO  
%.fwNS  
5
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return n; 5CH8;sMK  
} bZj5qjl`x  
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} 'c >^Aai  
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^ 7)H;$  
/* |f$gQI!XW  
**SiteInfoBean.java ]9wTAb  
*/ (I{+%  
package NetFox; bcAk$tA2  
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public class SiteInfoBean { a,n#E!zT?w  
9w1`_r[J  
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private String sSiteURL; //Site's URL i|S/g.r  
private String sFilePath; //Saved File's Path $2Bll5!]  
private String sFileName; //Saved File's Name v9#F\F/  
private int nSplitter; //Count of Splited Downloading File RS2uk7MB  
bY~V?yNgKM  
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public SiteInfoBean() I-Am9\  
{//nSplitter的缺省值为5 w.+G+r=  
//default value of nSplitter is 5 ~{{7y]3M-  
this("","","",5); S&Hgr_/}c  
} gTdr  
h66mzV:`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \#C]|\  
{ i7&ay\+@  
sSiteURL= sURL; DJ1!Xuu  
sFilePath = sPath; /7ykmW  
sFileName = sName; $9W,1wg  
this.nSplitter = nSpiltter; iRV=I,  
QQ %W3D@  
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} UH((d*HX4  
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public String getSSiteURL() _Y)Wi[  
{ =t.T9'{  
return sSiteURL; vVjk9_Ul  
} SXNde@% {  
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public void setSSiteURL(String value) 5d-rF:#  
{ oS<*\!&D  
sSiteURL = value; m+x$LkP  
} "cvhx/\1#  
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p  
public String getSFilePath() n-OQCz9Xl  
{ j&q%@%Gm  
return sFilePath; H6lZ<R{=  
} +.uQToqy  
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public void setSFilePath(String value) *
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{ BP1<:T'.q`  
sFilePath = value; &@w0c>Y  
} 9vCCE[9  
oA;ZDO06r  
uSH_=^yTQ  
public String getSFileName() (N9g6V  
{ S.?DR3XLc  
return sFileName; /?V-  
} $M$-c{>s  
I2,AT+O<  
[* |+ it+!  
public void setSFileName(String value) ~9@83Cs2  
{ HKVtO%&  
sFileName = value; VuD{t
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} :4r*Jju<V  
AP ]`'C  
oFsV0 {x%)  
public int getNSplitter() F'T.-lEO_d  
{ H
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return nSplitter; ryb81.|  
} F(Je$c/J|~  
/Zxq-9   
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public void setNSplitter(int nCount) {+EnJ"  
{ d-z[=1m  
nSplitter = nCount; Zh`[A9I/  
} _n&#e r  
} {HFx+<
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/* Ko|gH]B'  
**Utility.java pm[+xM9PB  
*/ @gw8r[  
package NetFox; I__a}|T%  
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public class Utility { m>*~tP  
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public Utility() 8Y:x+v5  
{ }T}xVd0  
(O&HCT|  
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} 7}`FXB  
Fh/sD?  
//线程睡眠 [2!C^\t  
public static void sleep(int nSecond) "]\3t;IT  
{
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try{ ph~BxK )i6  
Thread.sleep(nSecond); ux6p2Sk;K  
} T wzpq1  
catch(Exception e) ;d FJqo82  
{ %"WhD'*z}  
e.printStackTrace (); \s!x;nw[  
} pF(6M3>IN  
} #$F*.vQSs+  
kdaq_O:s  
//日志 M`E}1WNQ?]  
public static void log(String sMsg) )JJF}m=  
{ vin3 i&k  
System.err.println(sMsg); Eu%E2A|`I  
} (6b0rqPF  
/U`p|M;  
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public static void log(int sMsg) fB]NEx|o~  
{ ^]Z@H/]H  
System.err.println(sMsg); KLG2
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} YOUB%N9+  
} =|2F?  
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0& ?L%Y  
/* :}-?X\|\  
**TestMethod.java {WQ6=wGpS  
*/ vKfjP_0$  
package NetFox; NK'@.=$  
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k|{ 4"4r  
public class TestMethod { /_YTOSZjm  
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>]o>iOz;]  
public TestMethod() Z]x6
np  
{ ///xx/weblogic60b2_win.exe mI]gDL1  
try{ 5"X@<;H%  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;--D?Gs]Qr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); lD-2 5~YV  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^AiQNL}  
fileFetch.start(); \L`x![$~q  
} $\|Q+7lQ  
catch(Exception e){e.printStackTrace ();} ?[P>2oz  
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} i%, 't  
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public static void main(String[] args) ia3!&rZ  
{ rm-;Z<  
new TestMethod(); PB!XApTb  
} y,bDi9*|  
} vVrM[0*c  
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