http断点续传简单实现（java)

/* JfMJF[Mb  
**SiteFileFetch.java XM$GQn]B  
*/ u=%y  
package NetFox; v{o? #Sk1  
import java.io.*; g^jJ8k,7(  
import java.net.*; ~]&B>q  
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public class SiteFileFetch extends Thread { `aIG;@
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SiteInfoBean siteInfoBean = null; //文件信息Bean 6#E7!-u(-  
long[] nStartPos; //开始位置 yr5NRs  
long[] nEndPos; //结束位置 aVP5%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,(P %z.P@  
long nFileLength; //文件长度 *%X.ym'  
boolean bFirst = true; //是否第一次取文件 T8U[xu.>  
boolean bStop = false; //停止标志  =^Th[B  
File tmpFile; //文件下载的临时信息 S/VA~,KCe;  
DataOutputStream output; //输出到文件的输出流 Q\|18wkW  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Lx%:t YZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException HcA[QBh  
{ [<yz)<<  
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5C B%=iL{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); mbyih+amCr  
if(tmpFile.exists ()) ;Z*'
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{ (-\]A|
 
bFirst = false; PcB{=L  
read_nPos(); QWw"K$l  
} ;u,
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else ojoxXly`  
{ p5-<P?B  
nStartPos = new long[bean.getNSplitter()];  DwXU  
nEndPos = new long[bean.getNSplitter()]; pw3(t  
} S;8.y
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} t@)my[!  
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public void run() r{S=Z~J  
{ 4:U0f;Fs  
//获得文件长度 dKm`14f]@G  
//分割文件 Jn*Na
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//实例FileSplitterFetch E67XPvo1+@  
//启动FileSplitterFetch线程 i:d`{kJ|[  
//等待子线程返回 ,Aj }]h\L  
try{ wu2:'y>n  
if(bFirst) #EG?9T  
{ E_3r[1l  
nFileLength = getFileSize(); n'?4.tb  
if(nFileLength == -1) "U{,U`@?  
{ r1G8]agO  
System.err.println("File Length is not known!"); 4\ FP  
} |'<vrn  
else if(nFileLength == -2) xl8#=qmCD  
{ y\#o2PVmY  
System.err.println("File is not access!"); nhewDDu  
} j&CZ=?K^c  
else q`^3ov^</  
{ WYLX?x  
for(int i=0;i<nStartPos.length;i++) >)^NJ2Fd  
{ <Y>3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,eXFN?CB  
} (@q3^)I4  
for(int i=0;i<nEndPos.length-1;i++) )[jy[[K(  
{ g/#~N~&  
nEndPos = nStartPos[i+1]; YBvd q1  
} o@3B(j;J`  
nEndPos[nEndPos.length-1] = nFileLength; /UHp [yod  
} vLDi ;  
} 43L|QFo  
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*S4aF*Qk  
//启动子线程 TKOP;[1h  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1Nj=B_T  
for(int i=0;i<nStartPos.length;i++) f=m/ -mAA  
{ o?wt$j-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l3p3tT3+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kOipH |.x  
nStartPos,nEndPos,i); dE [Ol   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2.f|2:I  
fileSplitterFetch.start(); 9"ugz^uKt  
} AS|Rd+.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y]'CXCml)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); dIJGB==  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Gw{+xz KJ  
nEndPos = " + nFileLength); C3}Aq8$6  
// fileSplitterFetch[nPos.length-1].start(); yp+F<5o  
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//等待子线程结束 dB3N%pB^  
//int count = 0; %S`ik!K"I  
//是否结束while循环 7Z0/(V.-  
boolean breakWhile = false; }g{_AiP rv  
2ykCtRe  
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while(!bStop) JIxiklk  
{ %[Zz0|A  
write_nPos(); lzDdD3Ouc  
Utility.sleep(500); ]"sRS`0+  
breakWhile = true; v[&'k\  
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for(int i=0;i<nStartPos.length;i++) _wh
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{ |<(t}}X  
if(!fileSplitterFetch.bDownOver) XLb0 9;  
{ tjxvN 4l  
breakWhile = false; C:GvP>  
break; fxtxu?A>  
} o56
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} Ae49n4J  
if(breakWhile) I4ilR$jg  
break; YPszk5hn  
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//count++; O]qPmEj  
//if(count>4) /9_#U#vhY  
// siteStop(); 2B` 8
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} +< KNY  
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System.err.println("文件下载结束！"); hYb9`0G"2  
} C`4gsqD;Z  
catch(Exception e){e.printStackTrace ();} .pvxh|V  
} <xlm K(  
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//获得文件长度 [5Y<7DS
 
public long getFileSize() <&U!N'CE  
{  O<GF>  
int nFileLength = -1; O >FO>  
try{ Km*<Kfcz  
URL url = new URL(siteInfoBean.getSSiteURL()); lIh[|]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]yLhJ_^  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9=$!gC)  
b
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int responseCode=httpConnection.getResponseCode(); 'msmX
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if(responseCode>=400) >IY,be6>P  
{ `o si"o9  
processErrorCode(responseCode); / Z!i;@Wf  
return -2; //-2 represent access is error D$nK`r  
} p
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@ Nb%L&=P8  
String sHeader; <zfKC  
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for(int i=1;;i++) Ror2qDF  
{ LC-)'Z9}5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (vQ+e
 
//Utility.log(in.readLine()); <v$QM;Ff  
sHeader=httpConnection.getHeaderFieldKey(i); s, XM9h>P4  
if(sHeader!=null) Y8ehmz|g]J  
{ H06Bj(Y!  
if(sHeader.equals("Content-Length")) G$5m$\K  
{ ]W) jmw'mo  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \+Y!ILOI  
break; GDPo`#~  
} HFS
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} jvs[ /  
else rAXX}"l6s  
break; |Td5l?  
}
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} >n!ni(  
catch(IOException e){e.printStackTrace ();} ~HDdO3  
catch(Exception e){e.printStackTrace ();} Np)aS[9W  
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Utility.log(nFileLength); i&Kz*,pt  
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return nFileLength; xj
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} VzwPBQ -  
@2' %o<lF  
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//保存下载信息（文件指针位置） 7ZFJexN]  
private void write_nPos() o4)hxs  
{ F~_;o+e;X  
try{ &KqVN]1+^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^M|K;jt>  
output.writeInt(nStartPos.length); oJY[{-qW  
for(int i=0;i<nStartPos.length;i++) #@Y/{[s|@  
{ 2k1aX~?  
// output.writeLong(nPos); QnK
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output.writeLong(fileSplitterFetch.nStartPos); _Bk U+=|J  
output.writeLong(fileSplitterFetch.nEndPos); )saR0{e0N  
} Q$=*aUU%G  
output.close(); }<[Db}?9  
} +LzovC@^  
catch(IOException e){e.printStackTrace ();} `6Hf&u<  
catch(Exception e){e.printStackTrace ();} 97!5Q~I  
} xl] ;*&  
=B(mIx;m  
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//读取保存的下载信息（文件指针位置） PZM42"[&  
private void read_nPos() MF.[8Zb  
{ T
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try{ % vS8?nG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8tQ|-l*  
int nCount = input.readInt(); vJCf~'  
nStartPos = new long[nCount]; t ;-L{`mW  
nEndPos = new long[nCount]; H_B~P%E@]  
for(int i=0;i<nStartPos.length;i++) =!<G!^  
{ mG(N:n%*K  
nStartPos = input.readLong(); nGa1a  
nEndPos = input.readLong(); T1NH eH>  
} v>-YuS  
input.close(); F?4Sz#  
} ;^-:b(E  
catch(IOException e){e.printStackTrace ();} [7\>"v6  
catch(Exception e){e.printStackTrace ();} e4.&aIC[  
} 6 =gp:I  
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private void processErrorCode(int nErrorCode) JO1 ,TtA  
{ Tsz NlRxc  
System.err.println("Error Code : " + nErrorCode); ./w{L"E  
} |.w;r   
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_413\`%8?  
//停止文件下载 ?q Xs-  
public void siteStop() l3J$md|f  
{ ;~/4d-  
bStop = true; a[C&e,)}  
for(int i=0;i<nStartPos.length;i++) "!q?P" @C  
fileSplitterFetch.splitterStop(); bK=c@GXS  
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} <t}?$1  
} u!1/B4!'O  
//负责部分文件的抓取 B8~=RmWLl  
**FileSplitterFetch.java (@Zcx9  
*/ _01Px a2.  
package NetFox; A3s57.Z]|  
/77z\[CeYH  
|Fv?6qw+  
import java.io.*; .#!mDlY;  
import java.net.*; ,- HIFbXx@  
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public class FileSplitterFetch extends Thread { 2R`u[  
#&siHHs \  
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String sURL; //File URL 4}-#mBV]/  
long nStartPos; //File Snippet Start Position wj%wp[KA$  
long nEndPos; //File Snippet End Position j=j+Nf$  
int nThreadID; //Thread's ID 9#@Zz4Ww  
boolean bDownOver = false; //Downing is over IVteF*8hU  
boolean bStop = false; //Stop identical ,F:=(21  
FileAccessI fileAccessI = null; //File Access interface (~#G'Hd  
}1m_o@{3P  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ( V4G<-jG  
{ O5-;I,)H  
this.sURL = sURL; x!?Z*v@I  
this.nStartPos = nStart; M 9"-WIG@h  
this.nEndPos = nEnd; 2Xgx*'t\  
nThreadID = id; NG9vml  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d@g2k> >  
} @HEPc95  
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public void run() }ywi"k4>  
{ M=%!IT  
while(nStartPos < nEndPos && !bStop) HV\"T(89  
{ jo0Pd_W8&  
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try{ xOIg|2^8  
URL url = new URL(sURL); BKA]G)G7u!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XGIpUz  
httpConnection.setRequestProperty("User-Agent","NetFox"); wLMvC{5  
String sProperty = "bytes="+nStartPos+"-"; bi,mM,N/  
httpConnection.setRequestProperty("RANGE",sProperty); l* Y[^'  
Utility.log(sProperty); |<Bpv{]P  
-S$$/sR  
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InputStream input = httpConnection.getInputStream(); 76cEKH
a<  
//logResponseHead(httpConnection); -+P7:4/  
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byte[] b = new byte[1024]; *?N<S$m  
int nRead; <E}N=J
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )ddsyFGW  
{ P6we(I`"2  
nStartPos += fileAccessI.write(b,0,nRead); +*a7GttU  
//if(nThreadID == 1) IJIQ" s  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S'@=3)  
} ND*]gM  
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Utility.log("Thread " + nThreadID + " is over!"); >zR14VO`_|  
bDownOver = true; q{@P+2<wF  
//nPos = fileAccessI.write (b,0,nRead); XnA6/^  
} 8.2`~'V  
catch(Exception e){e.printStackTrace ();} ;
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} 1;`Fe":;vC  
} CJA+v-  
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//打印回应的头信息 \G3!TwC%  
public void logResponseHead(HttpURLConnection con) [B,p,Q"  
{ 2 `&<bt[g  
for(int i=1;;i++) dXO=ZU/N  
{ CWvlr nv  
String header=con.getHeaderFieldKey(i); n?Zf/T  
if(header!=null) Y)OBTX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); M5u_2;3  
Utility.log(header+" : "+con.getHeaderField(header)); [R\=M'  
else ?cxr%`E  
break; 7@~QkTH~y  
} Y^3)!>  
} $_bZA;EMQ  
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public void splitterStop() * gHCy4u{  
{ MCHOK=G  
bStop = true; b[0S=e G  
} zn^v!:[  
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} {? 2;0}3?;  
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2_N/wR#=&  
/* w&C1=v -h  
**FileAccess.java #%WCL'6B  
*//文件访问(定位，写) tj0Qr-/  
package NetFox; Y"oDFo,  
import java.io.*; 4y>(RrVG  
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@Wz%KdXA  
public class FileAccessI implements Serializable{ jYk5~<\k  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Dt|fDw$]D  
RandomAccessFile oSavedFile; 19&)Yd1  
long nPos; %yKKUZ~  
_'lmCj8L  
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public FileAccessI() throws IOException j%u8=  
{ E@mkm  
this("",0); HT-PWk>2  
} 8? F 2jv  
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public FileAccessI(String sName,long nPos) throws IOException |G=FqAXH  
{ nUqL\(UuY  
oSavedFile = new RandomAccessFile(sName,"rw"); ]Y=S  
this.nPos = nPos; <b'1#Pd>0  
oSavedFile.seek(nPos); :ovt?q8">  
} Kk>DYHZ6y  
[tz u;/  
u]SZ{[e  
public synchronized int write(byte[] b,int nStart,int nLen) 90(UgK&Y  
{ V:8@)Hc=  
int n = -1; /D8EI  
try{ g<a<{|  
oSavedFile.write(b,nStart,nLen); _1\poAy  
n = nLen; ?ff [$ab  
} G1TANy  
catch(IOException e) 2;h+;G  
{ MU*It"@}2  
e.printStackTrace (); cPSti  
} pSXEJ 2k  
?F25D2[(  
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return n; DEcGFRgN~  
} ILNXaJ'0a  
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} w?i)/q  
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}q]jjs  
/* K,]woNxaw  
**SiteInfoBean.java r\B"?oqC  
*/ .}`V I`z*  
package NetFox; h*l cEzG?A  
N|o>%)R  
;)P5#S!n-  
public class SiteInfoBean { 2zM-Ob<U`  
i
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private String sSiteURL; //Site's URL N?zV*ngBS  
private String sFilePath; //Saved File's Path @??u})^EL  
private String sFileName; //Saved File's Name Z|}H^0~7S  
private int nSplitter; //Count of Splited Downloading File :|Upx4]Ec  
4':MI|/my_  
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public SiteInfoBean() :Fc8S9  
{//nSplitter的缺省值为5 -&$%|cyThQ  
//default value of nSplitter is 5 >6w@{p2B  
this("","","",5); Y1|^>C#
a  
} i"vDRrDe  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :)j7U3u  
{ |K6nOX!i  
sSiteURL= sURL; qR_SQ VN  
sFilePath = sPath; &hO$4qtN  
sFileName = sName; T:Bzz)2/  
this.nSplitter = nSpiltter; KoFv0~8Q  
? 1GJa]G  
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} sFCf\y  
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public String getSSiteURL() ~R)1nN|  
{ =1eV   
return sSiteURL; G}Gb|sD Zq  
} }!Xf&c{7{  
1+Sg"?8  
N-Qu/,~+  
public void setSSiteURL(String value) x4@MO|C  
{ Cy]"  
sSiteURL = value; a$A2IkD  
} xJ$Rs/9C  
haN"/C^  
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public String getSFilePath() aD0Q0C+  
{ DZ,<Jmg&e*  
return sFilePath; \ =S3 L<  
} `d.Gw+Un  
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public void setSFilePath(String value) x-tm[x@;o  
{ u
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sFilePath = value; { 576+:*  
} gfV]^v  
9+W!k^VWq  
RzMA\r;#  
public String getSFileName() X #

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{ w 7Cne%J8  
return sFileName; >xklt"*U,  
} SlR7h$r'  
?56~yQF/2  
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public void setSFileName(String value) cPV
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{ N|bPhssFw  
sFileName = value; E*Pz <  
} | pF5`dX  
7k.d|<mRv  
]6jHIk|  
public int getNSplitter() /j`i/Ha1  
{ Og_2k ~  
return nSplitter; f34_?F<h  
} 6s> sj7  
~W2:NQ>i  
9yO{JgKA  
public void setNSplitter(int nCount) qn5yD!1  
{ `\Uc4lRS  
nSplitter = nCount; Iq^~  
} c(QG4.)m  
} ?ykVfO'  
#(m`2Z`H  
[lmHXf@1C  
/* PWADbu{
+  
**Utility.java d4b 9rtM  
*/ #9URVq,  
package NetFox; v(i1Z}*b  
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xC= y^- 1  
public class Utility { 3L'en  
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public Utility() 1EKcD^U,  
{ aeN}hG  
53g8T+`\(  
>xhd[  
} dt`9RB$  
\]tq7  
//线程睡眠 <1;,B%_^  
public static void sleep(int nSecond) MzBfHt'Rk  
{ 9^6|ta0;0  
try{ ,-w-su=J_  
Thread.sleep(nSecond); $)kk8Q4+K  
} jx^|2  
catch(Exception e) *+_fP|cv  
{ ;t.SiA  
e.printStackTrace (); L7~+x^kw  
} 6i*ArGA   
} S3%.-)ib  
">0/>>Ry  
//日志 d A_S"Zc  
public static void log(String sMsg) eO|^Lu]+  
{ jhjW*F<u  
System.err.println(sMsg); ]# tGT0   
} clPZd  
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l%-67(  
public static void log(int sMsg) 4~]8N@Bii  
{ $@+p~)r(l  
System.err.println(sMsg); >Hd~Ca>  
} 0 .6X{kO  
} 
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,d9%Ce.$2  
/* 1C5kS[!  
**TestMethod.java qaCi)f!Dl  
*/ r| 6S  
package NetFox; ?{ 8sT-Z-L  
1 $KLMW  
0-;DN:>  
public class TestMethod { Lz#$_Am'H  
|k['wqn"  
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public TestMethod() !Vp,YN+yN  
{ ///xx/weblogic60b2_win.exe ^C,/T2>  
try{ [0**&.obz  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); S<2CG)K[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Q KcF1?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d[P>jl%7  
fileFetch.start(); n)1  
} <{-(\>f!9  
catch(Exception e){e.printStackTrace ();} cpr{b8Xb8&  
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} 110>p  
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public static void main(String[] args) E,ZB;  
{ Mo/2,DiI5  
new TestMethod();  "df13U"  
} (>+k3  
} 5tgILxSK  
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