http断点续传简单实现（java)

/* *"Ipu"G5?  
**SiteFileFetch.java #kV`G.EX  
*/ 9\i,3:Qc  
package NetFox; Tc
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import java.io.*; UGPD5wX?  
import java.net.*; Tp`by 1s  
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public class SiteFileFetch extends Thread { ^=wG#!#V"1  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #uT-_L}sw  
long[] nStartPos; //开始位置 ?iUAzM8  
long[] nEndPos; //结束位置 8KW}XG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L;'+O u  
long nFileLength; //文件长度 r$6z{Na\[  
boolean bFirst = true; //是否第一次取文件 #oi4!%*M  
boolean bStop = false; //停止标志 fdCsn:  
File tmpFile; //文件下载的临时信息 .Lp0_R@  
DataOutputStream output; //输出到文件的输出流 a$FELlMv  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Sg0 _l(  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y=4,d4uu  
{ }$;T.[ ~  
siteInfoBean = bean; l9q ygh  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \sF}NBNT@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v.,C"^W  
if(tmpFile.exists ()) {JzX`Z30l  
{ 8Hs>+Udl  
bFirst = false; yU*j{>%RsK  
read_nPos(); lyx p:  
} 6pQ#Zg()vp  
else ^[8e|,U  
{ ^owEB%  
nStartPos = new long[bean.getNSplitter()]; 8sg8gBt  
nEndPos = new long[bean.getNSplitter()]; .dVo[m;
 
} JB'q_dS}  
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} g{f1JTJ7  
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public void run() q=}Lm;r  
{ j46fQ  
//获得文件长度 c:51In|~{C  
//分割文件 ZQnJTS+Rd  
//实例FileSplitterFetch 2anx]QV4  
//启动FileSplitterFetch线程 #=b_!~:%  
//等待子线程返回 ((Ec:(:c  
try{ I [0od+K  
if(bFirst) ]{nFB3vtB  
{ Y1Bj++?2  
nFileLength = getFileSize(); Sy'/%[+goJ  
if(nFileLength == -1) ev#d1s|<S  
{ M{:gc7%  
System.err.println("File Length is not known!"); WUdKj  
} ]ODC+q1  
else if(nFileLength == -2) .F?yt5{5No  
{ pR&cdORsP  
System.err.println("File is not access!"); _ts0@Z_:  
} netKt_  
else HPCgv?E3  
{ 7J,W#Ql)5  
for(int i=0;i<nStartPos.length;i++) }!& w<wR  
{ /^#k/z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @"kA&=0;|J  
} i,S%:0c7)  
for(int i=0;i<nEndPos.length-1;i++) rNqJL_!  
{ nV McHN   
nEndPos = nStartPos[i+1]; HQaKG4Z  
} [lQp4xgxi  
nEndPos[nEndPos.length-1] = nFileLength; ,ye>D='  
} %g0"Kj5  
} }`IN5NdYp  
c$?qN&X_K  
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//启动子线程 nPfVZG
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <hdR:k@#  
for(int i=0;i<nStartPos.length;i++) //e.p6"8h  
{ _w^p~To^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M[R, m_p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5gGYG]*l  
nStartPos,nEndPos,i); Vs8os+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =@binTC4  
fileSplitterFetch.start(); AT+|}B!  
} A,lcR:@w  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @p|[7'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); aAu upPu  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E`XUK,b  
nEndPos = " + nFileLength); 3l`yy])t  
// fileSplitterFetch[nPos.length-1].start(); [G[HQ)A  
b\][ x6zJp  
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//等待子线程结束 <3 AkF# C9  
//int count = 0; idPkJf/  
//是否结束while循环 i{T0[\4  
boolean breakWhile = false; 2*Z~JM  
P)^K&7X  
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while(!bStop) ]Vl*!,(i  
{ MrLDe{^C2  
write_nPos(); Y$Js5K@F  
Utility.sleep(500); #g{ZfO[#  
breakWhile = true; KTBsH;6  
[ #A!B#`  
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for(int i=0;i<nStartPos.length;i++) YANg2L>MK  
{ x nWapG  
if(!fileSplitterFetch.bDownOver) /qo.Z  
{ /_x?PiL  
breakWhile = false; +%?_1bGX>  
break; Bu>srX9f  
} )f(#Fn  
} -:a 9'dT  
if(breakWhile) 4rwfY<G  
break; @ L%3}  
 Cg}cD.  
8
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//count++; uzho>p[ae  
//if(count>4) H`),PY2  
// siteStop(); +X cB5S>  
} _ 97F  
l]T|QhiVd  
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System.err.println("文件下载结束！"); s#)fnNQ,  
} @]Iku6d-  
catch(Exception e){e.printStackTrace ();} 46Nl];g1`  
} *1ku2e]z  
#kA/,qyM  
IA$:r@QNx8  
//获得文件长度 opte)=]J  
public long getFileSize() }j+ZF'#  
{ iZgv VH  
int nFileLength = -1; ="d}:Jl  
try{ )(PA:j  
URL url = new URL(siteInfoBean.getSSiteURL()); r$=iM:kERC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P9G c)$6{p  
httpConnection.setRequestProperty("User-Agent","NetFox"); a&.8*|w3  
35B0L.R  
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int responseCode=httpConnection.getResponseCode(); EXS 1.3>  
if(responseCode>=400) ^Ml)g=Fq  
{ ;5PXPpJ  
processErrorCode(responseCode); ::9U5E;!  
return -2; //-2 represent access is error +QtK "5M  
} ojT TYR{  
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String sHeader; Y71io^td~j  
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for(int i=1;;i++) ,kpkXK  
{ Zh{Pzyp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); yJppPIW^  
//Utility.log(in.readLine()); dE
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sHeader=httpConnection.getHeaderFieldKey(i); &h
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if(sHeader!=null) [Sg1\UTl  
{ &Jk0SUk MP  
if(sHeader.equals("Content-Length")) 8JJqEkQ  
{ s34{\/'D+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Gi6s
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break; 3-lJ]7OT  
} S'9T>&<Kn  
} 9=ns.r  
else U;`N:~|p#  
break; ?`uY*+u  
} Eu l,1yR  
} R',Q)<  
catch(IOException e){e.printStackTrace ();} ,=Xr'7w,  
catch(Exception e){e.printStackTrace ();} *6df|q  
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Utility.log(nFileLength); !
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return nFileLength; ;v^tUyhCb  
} 1}Tbp_  
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<wW#Wnc]  
//保存下载信息（文件指针位置） P5P:_hr  
private void write_nPos() l"W9uS;\T  
{ ]EnB`g(4;  
try{ E<:XHjm  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #@w8wCj  
output.writeInt(nStartPos.length); +j1s*}8  
for(int i=0;i<nStartPos.length;i++) VY<$~9a&1  
{ 9]c2ub7  
// output.writeLong(nPos); FWq+'GkSV  
output.writeLong(fileSplitterFetch.nStartPos); Q]S~H+eRy  
output.writeLong(fileSplitterFetch.nEndPos); l<ag\ d  
} 2RFYnDN  
output.close(); s+#gH@c  
} IGV@tI  
catch(IOException e){e.printStackTrace ();} Nv,1F  
catch(Exception e){e.printStackTrace ();} -=H*(M  
} yS[:C 2v  
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//读取保存的下载信息（文件指针位置） n;@PaE^8=  
private void read_nPos() s )POtJ<  
{ +0{m(
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try{ 6NPCp/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); MCZTeYnx  
int nCount = input.readInt(); EcxPbRg  
nStartPos = new long[nCount]; <1Y
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nEndPos = new long[nCount]; q6bi{L@/R  
for(int i=0;i<nStartPos.length;i++) LBq~?Q.e  
{ )e
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nStartPos = input.readLong(); (dd+wx't  
nEndPos = input.readLong(); 5=WzKM  
} 12`q9Io"  
input.close(); 'W(+rTFf!  
} cfBq/2I  
catch(IOException e){e.printStackTrace ();} AyKvh  
catch(Exception e){e.printStackTrace ();} 0"
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} E
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private void processErrorCode(int nErrorCode) x$Y44v'>  
{ 2BZYC5jy  
System.err.println("Error Code : " + nErrorCode); sD H^l)4h  
} ROlef;/A  
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b`){f\#t  
//停止文件下载 <o@&I " o  
public void siteStop() ajC'C!"^Ty  
{ W/!M eTU&E  
bStop = true; R4"*<%1  
for(int i=0;i<nStartPos.length;i++) @}eEV[Lli  
fileSplitterFetch.splitterStop(); ^,*ED Yz  
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} a8ya5EO  
} I@Pp[AyG  
//负责部分文件的抓取 U_i%@{  
**FileSplitterFetch.java K&Ner(/X`6  
*/ ZG[P?fM  
package NetFox; @ x_.  
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import java.io.*; 5b>-t#N,  
import java.net.*; yY_(o]k  
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public class FileSplitterFetch extends Thread { GKT2x '(e  
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String sURL; //File URL G&=4@pLY5  
long nStartPos; //File Snippet Start Position yHhx- `  
long nEndPos; //File Snippet End Position Le;;
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int nThreadID; //Thread's ID x93h{Kf  
boolean bDownOver = false; //Downing is over z"#iG
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boolean bStop = false; //Stop identical )3K#${p  
FileAccessI fileAccessI = null; //File Access interface Z/-9G  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p7et>;WRx  
{ :btb|^C  
this.sURL = sURL; lS@0 $  
this.nStartPos = nStart; ha[c<e]uo[  
this.nEndPos = nEnd; qE B3Y54+  
nThreadID = id; e_RLKFv7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 DrI"YX  
} TL&`Ywy  
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public void run() ?QA![  
{ W*J_PL9j  
while(nStartPos < nEndPos && !bStop) PLD&/SgP*  
{ & -r^Q  
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try{ U*sjv6*T  
URL url = new URL(sURL); w`BY>Xft0
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )/HbmtXqI  
httpConnection.setRequestProperty("User-Agent","NetFox"); KLb"_1z  
String sProperty = "bytes="+nStartPos+"-"; [|iWLPO1&k  
httpConnection.setRequestProperty("RANGE",sProperty); +85#`{ D  
Utility.log(sProperty); y7CC5S?  
5k:SD7^b  
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InputStream input = httpConnection.getInputStream(); yS#)F.  
//logResponseHead(httpConnection);  NOY`1i  
k=]#)A(#C  
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byte[] b = new byte[1024]; &10l80vj  
int nRead; M3XG s|gw  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?^Gi;d5  
{ ,+w9_Gy2H  
nStartPos += fileAccessI.write(b,0,nRead); w8=&rzr8  
//if(nThreadID == 1) Vn&{yCm3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r]q;>\T'  
} f^JiaU4 [  
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r ^=rs!f@  
Utility.log("Thread " + nThreadID + " is over!"); 7bV(eV  
bDownOver = true; NS<C"O  
//nPos = fileAccessI.write (b,0,nRead); B":9C'tip  
} vEy0DHEE  
catch(Exception e){e.printStackTrace ();} sNaLz  
} I+oe{#
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} LTZ8Eu  
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//打印回应的头信息 Xr:gm`[  
public void logResponseHead(HttpURLConnection con) u+/Uc:XK)  
{ {c :7:  
for(int i=1;;i++) 6a*?m{  
{ J\@|c.ws  
String header=con.getHeaderFieldKey(i); [}Q_T.4)E  
if(header!=null) p9>{X\eT:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (rmOv\hG9V  
Utility.log(header+" : "+con.getHeaderField(header)); }VU^ 8
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else C/$bgK[ev  
break; s5bqS'%  
} 3_bE12  
} ZLj
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@V?T'@W7D  
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public void splitterStop() &Fiesi!tET  
{ W [
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bStop = true; Ln'y 3~@  
} ,.kJF4s&  
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} a8WWFAC[  
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m?<^b_a}  
/* ~8 B]  
**FileAccess.java f+cN'jH E  
*//文件访问(定位，写) 3"BSP3/[l  
package NetFox; ~'V&[]nh8  
import java.io.*; 0 k.\o"y  
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public class FileAccessI implements Serializable{ H#S`m  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 eJ*u]GH U  
RandomAccessFile oSavedFile; t$Bu<frQ  
long nPos; q+znb'i-x  
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public FileAccessI() throws IOException 216`rQ}z  
{ 2Z-[x9t  
this("",0); "MvSF1  
} nt]'>eX_}  
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public FileAccessI(String sName,long nPos) throws IOException z`qb>Y"xf3  
{ i]#"@xQ  
oSavedFile = new RandomAccessFile(sName,"rw"); Kv9$c(~#  
this.nPos = nPos; 3P
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oSavedFile.seek(nPos); "{S6iH)]8  
} &^UT  
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public synchronized int write(byte[] b,int nStart,int nLen) 0HO'%'Ga*  
{ csd9[=HW/Q  
int n = -1; eZoAy[  
try{ )Q 5 x
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oSavedFile.write(b,nStart,nLen); dWx@<(`OC  
n = nLen; VA>0Y
  
} p,V%wGM  
catch(IOException e) k|czQ"vaI  
{ y|0!sNg  
e.printStackTrace (); <vE
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} yH(3 m#  
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bv;.6C(T<  
return n; v.-r %j{I  
} e^<'H  
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} S"VO@
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/* l^XOW- ;u  
**SiteInfoBean.java No8-Hm  
*/ d A'0'M  
package NetFox; Bq;GO  
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public class SiteInfoBean { `g_r<EY8/  
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private String sSiteURL; //Site's URL (j~T7og  
private String sFilePath; //Saved File's Path V.9p4k`  
private String sFileName; //Saved File's Name d-
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private int nSplitter; //Count of Splited Downloading File \#PZZ
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public SiteInfoBean() KYZ#.f@  
{//nSplitter的缺省值为5 NiFe#SLA  
//default value of nSplitter is 5 ,J'_Vi  
this("","","",5); 8f<y~L_(`  
} [K@(,/$  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |g>
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{ uts>4r>+  
sSiteURL= sURL; : h(Z\D_  
sFilePath = sPath; f~*7hv\  
sFileName = sName; c3Gy1#f:#2  
this.nSplitter = nSpiltter; A|,qjiEJCc  
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} -$kIVh  
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public String getSSiteURL() kxN O9w  
{ AN6Q~%,  
return sSiteURL; MRw4?HqB  
} eX>*}pI  
ij|>hQC5i  
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public void setSSiteURL(String value) `|Hk+V  
{ hkyO_ns  
sSiteURL = value; 9J~\.:jH-  
} j:qexhtho  
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public String getSFilePath() [=BMvP5  
{ WF-jy7+  
return sFilePath; r{t6Vv2J  
} L&y"oAp<  
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public void setSFilePath(String value) !zm;C@}ln  
{ 4;W{#jk  
sFilePath = value; Cl9rJ oT  
} ^-Ygh[x  
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}3_b%{  
public String getSFileName() -
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{ <YtjE!2  
return sFileName; F~qZIggD  
} Ll-QhcC$  
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}#u #m.  
public void setSFileName(String value) 'e' p`*  
{ +}M3O]?4  
sFileName = value; `'^o45  
} ;x2o|#`b  
oGB|k]6]|  
 T&MhSJf#  
public int getNSplitter() me{u~9&  
{ R|'W#"{@  
return nSplitter; Y)]C.V,~  
} rX /'  
+
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public void setNSplitter(int nCount) ;1PJS_@rX  
{ j)Ak:l%a  
nSplitter = nCount; 4bp})>}jB  
} '2i !RT-  
} ^9Cu?!xu0  
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/* :{ZwzJ  
**Utility.java a*LfT<hmU3  
*/ X[r0$yuE  
package NetFox; 3(\D.Z  
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public class Utility { '7PaJj=Nx  
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public Utility() i>,AnkI&  
{ T}=^D=  
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} OR!W3 @  
![_0GF
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//线程睡眠 xQDQgvwa  
public static void sleep(int nSecond) HnKgD:  
{ _fu <`|kc  
try{ M /v@C*c  
Thread.sleep(nSecond); !rr,(!Ip?O  
} hL6;n*S=  
catch(Exception e) ~gff{Nzk  
{ fV5$[CL1  
e.printStackTrace (); D?"P\b[/  
} DE/SIy?  
} isd-b]@:Lc  
TUC)S&bC  
//日志 j|wN7@Zc  
public static void log(String sMsg) [8IO0lul+  
{ wB[f%mHs  
System.err.println(sMsg); c+e?xXCEAz  
} o.A:29KoU  
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]#^v754X^T  
public static void log(int sMsg) ]S[/a  
{ .
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System.err.println(sMsg); 4Ex&AR8  
} IF0!@f  
} bI|G %  
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/* 'xj5R=V  
**TestMethod.java l7qW)<r  
*/ MkoK(m{7  
package NetFox; y42Cg  
aMY@**^v  
~[t#$2d}  
public class TestMethod { `qs}L  
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public TestMethod() -Q@f),  
{ ///xx/weblogic60b2_win.exe -'d:~:1f  
try{ yiC7)=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0t^FM<7G  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5kTs7zJ^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Y06^M?}  
fileFetch.start(); aF^NYe  
} 94ruQ/   
catch(Exception e){e.printStackTrace ();} iLuC_.'u=  
}8
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(vZ-0Ep}  
} m =b7 r  
!Z:XSF[T  
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public static void main(String[] args) mXp#6'a  
{ X'PZCg W  
new TestMethod(); S \]O8#OX  
} d7vPZ_j^z  
} s{'Sl{-Eu  
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