http断点续传简单实现（java)

/* vUe *  
**SiteFileFetch.java J+jmSK%z  
*/ Cfo 8gX*  
package NetFox; Lo5@zNt%W  
import java.io.*; y[6&46r7D  
import java.net.*; jUvA<r  
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public class SiteFileFetch extends Thread { puN=OX}C  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 'QojSq   
long[] nStartPos; //开始位置 ,G|aLBn  
long[] nEndPos; //结束位置 5;8B!%b  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \K~fRUo]=c  
long nFileLength; //文件长度  ;c Co+(  
boolean bFirst = true; //是否第一次取文件 #0
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boolean bStop = false; //停止标志 "%''k~UD4  
File tmpFile; //文件下载的临时信息 dyiEK)$h  
DataOutputStream output; //输出到文件的输出流 "C.7;Rvkp>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^y0C5Bl;  
public SiteFileFetch(SiteInfoBean bean) throws IOException [Cj)@OC  
{ !{tiTA  
siteInfoBean = bean; )9L pX  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); F4E3c4 81  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); rjHIQC C  
if(tmpFile.exists ()) uk[< 6oxz  
{ $KWYe{#  
bFirst = false; kgapTv>q  
read_nPos(); Fra>|;do  
} 76A>^Bs\/  
else "lz[zFnO  
{ Secq^#]8  
nStartPos = new long[bean.getNSplitter()]; xVkTRCh  
nEndPos = new long[bean.getNSplitter()]; {XD/8m(hN|  
} S=H_9io  
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} 1i/::4=  
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public void run() I+"?,Ej$K  
{ Th^(f@.w  
//获得文件长度 N^ s!!Sbpq  
//分割文件 p&sK\
 
//实例FileSplitterFetch dG-or  
//启动FileSplitterFetch线程 XQ3*  
//等待子线程返回 QhXC>)PW  
try{ H8$<HhuZM  
if(bFirst) S1^nC tSF  
{ /ggkb8<3  
nFileLength = getFileSize(); Bug}^t{M  
if(nFileLength == -1) YYE8/\+B.  
{ hkwa""-  
System.err.println("File Length is not known!"); {!}F :~*r  
} w^])(  
else if(nFileLength == -2) qfGtUkSSb  
{ 6`qr:.  
System.err.println("File is not access!"); Q:kVCm/;  
} i&pJg1  
else 6b]1d04hT  
{ ZEj!jWP2m  
for(int i=0;i<nStartPos.length;i++) /MKNv'5&!%  
{ 0SMQDs5j  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); w3=)S\  
} FL`1yD^2  
for(int i=0;i<nEndPos.length-1;i++)
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{ XpgV09.EE  
nEndPos = nStartPos[i+1]; d]CviQUq  
} UW hn1N  
nEndPos[nEndPos.length-1] = nFileLength; NFY|^*bll  
} m0|Ae@g~3  
} Zj1ZU[BEcL  
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//启动子线程 0L:V#y-*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; lmhbF  
for(int i=0;i<nStartPos.length;i++) 1Y=AT!"V  
{ eu}Fd@GO  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &nqdl+|G*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .]j#y9>&w%  
nStartPos,nEndPos,i); #9$V 08  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +ze}0lrEL  
fileSplitterFetch.start(); CF|moc:;  
} m<4s*q0\i  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V$dJmKg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); G@!_ZM8h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g\o{}Q%X  
nEndPos = " + nFileLength); x
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// fileSplitterFetch[nPos.length-1].start(); 'Aj(i/CM  
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//等待子线程结束 ~$4]HDg  
//int count = 0; -`!_h[   
//是否结束while循环 B2~f;zy`  
boolean breakWhile = false; h; 'W :P  
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while(!bStop) {)B9Z I{+A  
{ uxa=KM1H  
write_nPos(); g7xbyBo7  
Utility.sleep(500); +/y{^}b/  
breakWhile = true; xLx"*jyL  
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for(int i=0;i<nStartPos.length;i++) 3ppuQQ  
{ yS[z2:!  
if(!fileSplitterFetch.bDownOver) ]3L@$`ys  
{ of8mwnZR  
breakWhile = false; 3`58ah  
break; ;>9OgO  
} ^^G-kg  
} .OmQ'  
if(breakWhile) ?k{|Lk  
break; L5Urg*GNL  
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4~O6$;!|~  
//count++; Zc-#;/b3T  
//if(count>4) GAv)QZyV$  
// siteStop(); S8O
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} 9>N\sOh  
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System.err.println("文件下载结束！"); 8+"10q-  
} /61by$
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catch(Exception e){e.printStackTrace ();} LGIalf*7  
} ispkj'  
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7}Bj|]b)~  
//获得文件长度 }>V/H]B  
public long getFileSize() MZT6g.ny  
{ a3Y{lc#z}  
int nFileLength = -1; )ZHc$+fU  
try{ &yE1U#J(  
URL url = new URL(siteInfoBean.getSSiteURL()); $+Vmw
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '!!e+\h#  
httpConnection.setRequestProperty("User-Agent","NetFox"); Sv7 i! j  
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int responseCode=httpConnection.getResponseCode(); DU;[btK>  
if(responseCode>=400) I*Vt,JYx  
{ %N)e91wC  
processErrorCode(responseCode); VCjq3/[_  
return -2; //-2 represent access is error B&?fM~J  
} H+a~o=/cR  
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String sHeader; :$=
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- %|P  
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for(int i=1;;i++) 5MxH)~VQoM  
{ {>@QJlE0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ! .AhzU1%Y  
//Utility.log(in.readLine()); %JQ~!3  
sHeader=httpConnection.getHeaderFieldKey(i); Va7c#P?  
if(sHeader!=null) ~LbS~_\C=  
{ O#Z/+\U  
if(sHeader.equals("Content-Length")) -I ?z-?<D  
{ Y]N~vD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }|Uj"e  
break; t05_Px!mW  
} RdgVBG#Z1  
} X8Xn\E  
else V
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break; v dU%R\  
} a9=>r  
} ob E:kNE9  
catch(IOException e){e.printStackTrace ();} OkpwhkPL5  
catch(Exception e){e.printStackTrace ();} q +R*Hi  
#$FrFU;ZR  
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Utility.log(nFileLength); FEF"\O|Q  
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return nFileLength; ,h^r:g  
} o@9+mM"B)  
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//保存下载信息（文件指针位置） bKMWWJf*'  
private void write_nPos() ZqQ*}l5  
{ Stxp3\jEn  
try{ O$qtq(Q%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); xvmt.
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output.writeInt(nStartPos.length); ;L~p|sF  
for(int i=0;i<nStartPos.length;i++) BC! 6O/
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{ U\jb"  
// output.writeLong(nPos); t<638`{kk  
output.writeLong(fileSplitterFetch.nStartPos); )JhT1j
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output.writeLong(fileSplitterFetch.nEndPos); %
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} E1 |<Pt  
output.close(); lpy:3`ti  
} S8" f]5s  
catch(IOException e){e.printStackTrace ();} QXVC\@  
catch(Exception e){e.printStackTrace ();} h?Nek+1'  
} OQp, 3M{_  
+-BwQ{92[:  
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//读取保存的下载信息（文件指针位置） B+] D5K  
private void read_nPos() =dzWmL<~8  
{ nPFwPk8=M  
try{ J;}3t!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); c8ZA5|  
int nCount = input.readInt(); D!F 2l_  
nStartPos = new long[nCount]; ^m!_2_q  
nEndPos = new long[nCount]; <*(^{a.O  
for(int i=0;i<nStartPos.length;i++) &!L:"]=+  
{ h2~4G)J  
nStartPos = input.readLong(); \X|sU:g  
nEndPos = input.readLong(); iWA|8$u4gm  
} C ^w)|2o}  
input.close(); ]$A(9Pn"  
} ]~0}=,H$N  
catch(IOException e){e.printStackTrace ();} !GwL,)0@^  
catch(Exception e){e.printStackTrace ();} g(Yb^'X/  
}
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/
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private void processErrorCode(int nErrorCode) G[,Q95`w?<  
{ >Cr\y  
System.err.println("Error Code : " + nErrorCode); 3jZ6kfj  
} Y32 "N[yw  
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//停止文件下载 u92^(|  
public void siteStop() xSMt*]=9  
{ 5/MKzoB  
bStop = true; ^D{lPu 3  
for(int i=0;i<nStartPos.length;i++) -/
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fileSplitterFetch.splitterStop(); .}B(&*9,v  
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} ~" i0x
 
} 1}%B%*N  
//负责部分文件的抓取 T{+Z(L  
**FileSplitterFetch.java B<?wh0  
*/ 3Ot~!AlR  
package NetFox; RY9V~8|M  
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import java.io.*; qS|\JG  
import java.net.*; T>`74B:  
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public class FileSplitterFetch extends Thread { O%8EZyu  
9(4&KZpK  
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String sURL; //File URL c!
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long nStartPos; //File Snippet Start Position *Hz^K0:8(  
long nEndPos; //File Snippet End Position f+_h !j  
int nThreadID; //Thread's ID Z?5V4F:f  
boolean bDownOver = false; //Downing is over =O).Lx2J  
boolean bStop = false; //Stop identical "A$!, PX6  
FileAccessI fileAccessI = null; //File Access interface t. ='/`!N  
**3 z;58i  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q 11IkDa
  
{ )3Z ^h<"j  
this.sURL = sURL; T~0k"uTE  
this.nStartPos = nStart; (xHf4[[u  
this.nEndPos = nEnd; u&mS8i}  
nThreadID = id; @a:>
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 wMqX)}>  
} ?i
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public void run() a2'^8;U*_  
{ L|P5=/d  
while(nStartPos < nEndPos && !bStop) ^.dsW0"0  
{ &|3 $!S  
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try{ t3(
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URL url = new URL(sURL); J &pO%Q=b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FCi U  
httpConnection.setRequestProperty("User-Agent","NetFox"); [I!6PGx  
String sProperty = "bytes="+nStartPos+"-"; 2EZb )&Q  
httpConnection.setRequestProperty("RANGE",sProperty); Y2o?gug  
Utility.log(sProperty); $6OkIP.  
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InputStream input = httpConnection.getInputStream(); +_XzmjnDd  
//logResponseHead(httpConnection); .Asv%p[W  
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byte[] b = new byte[1024]; )E@A0W  
int nRead; @=}YTtq  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) r\qj!  
{ W`\R%>$H  
nStartPos += fileAccessI.write(b,0,nRead); C{gyj}5  
//if(nThreadID == 1) v\m ]A1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =R*qP;#  
} 79`AM X[b  
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t2,A@2DU2  
Utility.log("Thread " + nThreadID + " is over!"); +s- lCz  
bDownOver = true; h4q|lA6!k8  
//nPos = fileAccessI.write (b,0,nRead); z!l.:F  
} .pvi!NnL-  
catch(Exception e){e.printStackTrace ();} oE#d
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} ?c[*:N(  
} o.0ci+z@  
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//打印回应的头信息 At-U2a#J{  
public void logResponseHead(HttpURLConnection con) $s9Vrw0Z  
{ {r@Ty*W} L  
for(int i=1;;i++) gw,UQbnu  
{ ma"3qGy  
String header=con.getHeaderFieldKey(i); ]IoUwgpI)  
if(header!=null) h }B% /U  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >}+/{(K"E|  
Utility.log(header+" : "+con.getHeaderField(header)); 6Yx4lWBR?  
else .Fdgb4>BXX  
break; :2 *g~6  
} l c+g&f  
} 9FB19  
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public void splitterStop() R8ZK]5{o  
{ spt6]"Ni  
bStop = true; rg^'S1x|  
} e" St_z(  
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} 7
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/* eEuvl`&  
**FileAccess.java <StN%2WQ1  
*//文件访问(定位，写) .&DhN#EN0  
package NetFox; 9I}-[|`u  
import java.io.*; ,6-:VIHQ  
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public class FileAccessI implements Serializable{ vN`klDJgW[  
ibj87K  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vX/T3WV  
RandomAccessFile oSavedFile; A"L&a l$i  
long nPos; gt@m?w(  
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#qK:J;Sn3  
public FileAccessI() throws IOException |y
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{ f&Gt|  
this("",0); }H^+A77v  
} KV(Q;~8"X  
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public FileAccessI(String sName,long nPos) throws IOException !2ZF(@C/  
{ 4 o Fel.o  
oSavedFile = new RandomAccessFile(sName,"rw"); %nf6%
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this.nPos = nPos; 1`=nWy='  
oSavedFile.seek(nPos); k$blEa4  
} sB7# ~pA  
i<#QW'R(  
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3  
public synchronized int write(byte[] b,int nStart,int nLen) A1O'|7X  
{ MN\HDKN  
int n = -1; 4K\G16'$v  
try{ 8Vr%n2M  
oSavedFile.write(b,nStart,nLen); o~`/_+  
n = nLen; pH9VTM.*  
} \NPmym_6J  
catch(IOException e) `sn^ysp  
{ 4h|c<-`>t  
e.printStackTrace (); !LNayk's>  
} +S o4rA*9  
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return n; !|^|,"A)  
} c2l@6<W
w  
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} %)1y AdG 8  
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/* ,E S0NA  
**SiteInfoBean.java C5o#i*|  
*/ Y]'Z7<U}*E  
package NetFox; Va"0>KX  
<^#,_o,!  
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public class SiteInfoBean { ag [ZW  
*/`ki;\A  
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private String sSiteURL; //Site's URL +$ 'Zf0U  
private String sFilePath; //Saved File's Path hOjk3 k  
private String sFileName; //Saved File's Name j#!IuH\]  
private int nSplitter; //Count of Splited Downloading File cr7 }^s  
Tp?7_}tRi  
6m}Ev95  
public SiteInfoBean() rV` #[d  
{//nSplitter的缺省值为5 J,'M4O\S  
//default value of nSplitter is 5 'j#*6x
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this("","","",5); C0T;![/4A  
} (KjoSN( K  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |jGf<Bf5  
{ IaSR;/  
sSiteURL= sURL; <FV1Wz  
sFilePath = sPath; G#ZH.24Y  
sFileName = sName; <sb~ ^B  
this.nSplitter = nSpiltter; L>jY.d2w=K  
L+b6!2O,  

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} q+yQwX{  
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public String getSSiteURL() }|h# \$w  
{ Ua
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return sSiteURL; I fK,b*%  
} &GpRI(OB/+  
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public void setSSiteURL(String value) Dj"F\j 1  
{ Wf+cDpK  
sSiteURL = value; `KZm0d{H  
} 5'OrHk;u  
G30-^Tr   
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public String getSFilePath() E>6MeO  
{ zVViLUwG  
return sFilePath; 5%Y3 Kwyy  
} {&&z-^  
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; 5*&xz  
public void setSFilePath(String value) 7r6.n61F  
{ j`{?OYD  
sFilePath = value; Y
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} HY56"LZ$(}  
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sA+ }TNhq  
public String getSFileName() /:cd\A}  
{ ju8>:y8  
return sFileName; 1KU! tL  
} Cwv9 a^  
hZ|z|!g0  
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public void setSFileName(String value) Ki;*u_4{  
{ g_;\iqxL  
sFileName = value; /J]5H  
} jk;j2YNPw  
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public int getNSplitter() tm|ZBM  
{ z<MsKD0Q  
return nSplitter; tR#OjkvX  
} '+@=ILj>  
&T#;-`'  
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public void setNSplitter(int nCount) KqHyG  
{ em
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nSplitter = nCount; bTI|F]^!  
} ?e%ZOI  
} lt/1f{v[:  
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/* 'lH|eU&-  
**Utility.java Ugr!"Q#M  
*/ %aP!hy  
package NetFox; 0-B5`=yU  
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public class Utility { 1a/++4O.|  
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public Utility() ~]sc^[  
{ irZ]
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} M$wC=b  
R7%#U`Q^A  
//线程睡眠 +V2F#fI/  
public static void sleep(int nSecond) \P[Y`LYL  
{ C2!|OQ9A2  
try{ B.=FSow  
Thread.sleep(nSecond); .7J#_*NV  
} G0Iw-vf  
catch(Exception e) M*0]ai|;  
{ &s(^@Oa
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e.printStackTrace (); P1!qbFDv8  
} )705V|v  
} Zj(AJ*r  
VG5i{1 0  
//日志 _YRFet[,m  
public static void log(String sMsg) 9i:L&dN  
{ ;[ZEDF5H  
System.err.println(sMsg); Y_liA  
} _O?`@g?i  
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public static void log(int sMsg) hDDn,uzpd  
{ J4hL_i
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System.err.println(sMsg); I{|O "8  
} 
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} 6bg ;q(*7  
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/* =nHUs1rKn  
**TestMethod.java Lj({[H7D!  
*/ PI {bmZ  
package NetFox; RU|Q]Ymx  
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5  
$ Gf(38[w  
public class TestMethod { 1C+13LE$U  
}J}-//[A  
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public TestMethod() g _9C*  
{ ///xx/weblogic60b2_win.exe v&\Q8!r_  
try{ w7L{_aom  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \ #F  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +
Ze}
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SiteFileFetch fileFetch = new SiteFileFetch(bean); )D O?VRI  
fileFetch.start(); iI T;K@&  
} G[PtkPSJ  
catch(Exception e){e.printStackTrace ();} @?sRj&w  
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@mCEHI{P  
} 
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.^`{1%  
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public static void main(String[] args) 7sCG^&Y  
{ h,:m~0gmj  
new TestMethod(); ]h`&&Bqt  
} .vf'YNQ%  
} mY|)KJ  
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