http断点续传简单实现（java)

/* q$|0)}  
**SiteFileFetch.java v10mDr  
*/ r:
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package NetFox; U(P:Je  
import java.io.*; Z$1.^H.Db  
import java.net.*; )ph30B  
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public class SiteFileFetch extends Thread { R~!\-6%_  
/ Z1Wy-Z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean dA|Lufy#  
long[] nStartPos; //开始位置 !2#\| NJk  
long[] nEndPos; //结束位置 Q|Nzbmwh  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4p?+LdL  
long nFileLength; //文件长度 ,T/GW,?  
boolean bFirst = true; //是否第一次取文件 &+,:u*%  
boolean bStop = false; //停止标志 T0s35z9  
File tmpFile; //文件下载的临时信息 iF8@9m  
DataOutputStream output; //输出到文件的输出流 #gF2(iK6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BB0g}6M  
public SiteFileFetch(SiteInfoBean bean) throws IOException k"5`:qL  
{ \ hrBq^I  
siteInfoBean = bean; I7A7X*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Kq8(d`g}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); cl@kRX<7'  
if(tmpFile.exists ()) 2.!1kije  
{ F9v)R#u~  
bFirst = false; ~d&'Lp[3  
read_nPos(); Tm%WWbc  
} aD?# ,  
else ;,mBT[_ZO  
{ %Fs*
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nStartPos = new long[bean.getNSplitter()]; K?$9N}+  
nEndPos = new long[bean.getNSplitter()]; AL(n*,  
} i[o&z$JO  
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} >c}:   
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public void run() -hQ96S8  
{ &qNP?>C!=  
//获得文件长度 0W;q!H[G  
//分割文件 *iPs4Es-  
//实例FileSplitterFetch ,:c:6Y^  
//启动FileSplitterFetch线程 6.k^m&-A  
//等待子线程返回 -6AOK<kfI  
try{ 9cl{hdP{  
if(bFirst) Z@<q/2).|  
{ an-\k*w  
nFileLength = getFileSize(); [t {vYo  
if(nFileLength == -1) O)Xd3w'  
{ d]^\
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System.err.println("File Length is not known!"); Lr K9F^c  
} "1_{c *ck  
else if(nFileLength == -2) q2[+-B)m  
{ BT&rp%NO6l  
System.err.println("File is not access!"); czXI?]gg,  
} Ngn\nkf  
else ;Gjv9:hUn  
{ #Y/97_2 xa  
for(int i=0;i<nStartPos.length;i++) 2qt=jz\s  
{ qPp1:a"   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0Ei\VVK>  
} LBW.*PHW  
for(int i=0;i<nEndPos.length-1;i++) z~GVvgd  
{ tVC@6Z$  
nEndPos = nStartPos[i+1]; ^nG1/}  
} Vww@eK%5Q  
nEndPos[nEndPos.length-1] = nFileLength; ;+S2

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} Z}]:x `fXd  
} pA*D/P-  
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//启动子线程 9m<wcZ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P}ehNt*($  
for(int i=0;i<nStartPos.length;i++) ~r(g|?}P  
{ _bN))9 3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V`WI"HO+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gn-=##fT:i  
nStartPos,nEndPos,i); s#'|{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "
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fileSplitterFetch.start(); [{hLF9yPx  
} NTXws4'D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {Bav$kw;?e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); wJ;9),fL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", J`U$b+q6  
nEndPos = " + nFileLength); rU/-Wq`B  
// fileSplitterFetch[nPos.length-1].start(); 4v rm&k  
v1`bDS?*Q  
S/#) :,YS  
//等待子线程结束 zv$=*  
//int count = 0; dbf^A1HI  
//是否结束while循环 /ig^7+#  
boolean breakWhile = false; u!=]zW%  
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while(!bStop) &6|6J1c8  
{ \#h})`  
write_nPos(); O+CF/ipX/  
Utility.sleep(500); eY0Ly7  
breakWhile = true; yb@X*PW
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for(int i=0;i<nStartPos.length;i++) VWnu#_(  
{ bAA'=z<  
if(!fileSplitterFetch.bDownOver) d +*T@k]>M  
{ 17MN8SfQ  
breakWhile = false; m)tI  
break; `R4W4h'I  
} |q1b8A\  
} KDNTnA1c  
if(breakWhile) _*OaiEL+:  
break; *@b~f&Lx6  
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O
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//count++; -y7l?N5F>  
//if(count>4) ;ph+ZV  
// siteStop(); DYy@t^sC  
} `Z;B
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System.err.println("文件下载结束！"); ];
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} ]ly)z[is"]  
catch(Exception e){e.printStackTrace ();} [4V|UvKz  
} bi4^ zaCEE  
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J.CZR[XF#  
//获得文件长度 zD#+[XI]K  
public long getFileSize() f4@#pnJ3po  
{ D9@<#2-  
int nFileLength = -1; ~@a) E+LsF  
try{ W2X+NacD  
URL url = new URL(siteInfoBean.getSSiteURL()); }[hDg6i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Aw_R $  
httpConnection.setRequestProperty("User-Agent","NetFox"); AR[M8RA  
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int responseCode=httpConnection.getResponseCode(); {4V:[*
3  
if(responseCode>=400) &L[8Mju6  
{ B8BY3~}]  
processErrorCode(responseCode); ]%ZjD  
return -2; //-2 represent access is error $AL|d[[T[  
} )nbyV a  
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String sHeader; T^f&58{ 7  
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for(int i=1;;i++) `gA5P %  
{ R,(+NT$
 
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); `qYc#_ELv  
//Utility.log(in.readLine()); xr1I8 5kM  
sHeader=httpConnection.getHeaderFieldKey(i); 0lJBtk9wn  
if(sHeader!=null) FrE/K_L  
{ i >/@]2  
if(sHeader.equals("Content-Length")) fu7[8R"{  
{ ;#Crh}~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QKL]O*  
break; QtO[g  
} =-a?oH-  
} y+~Aw"J}  
else +$pO  
break; O+3D 5*  
} vp9E}ga  
} C9^elcdv  
catch(IOException e){e.printStackTrace ();} `zvT5=*-#  
catch(Exception e){e.printStackTrace ();} 7u&H*e7  
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Utility.log(nFileLength); .jG.90  
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return nFileLength; a}+_Yo(Q  
} aX%g+6t2  
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//保存下载信息（文件指针位置） ,"HpV  
private void write_nPos() n B|C-.F  
{ s*A|9uf5  
try{ jak|LOp  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0$dY;,Q.  
output.writeInt(nStartPos.length); 'rcsK  
for(int i=0;i<nStartPos.length;i++) E`Zh\u)  
{ 5E!|on  
// output.writeLong(nPos); gs2&0rnOy\  
output.writeLong(fileSplitterFetch.nStartPos); &`9bGO
  
output.writeLong(fileSplitterFetch.nEndPos); C J}4V!;|  
} nh_xbo5L[  
output.close(); 70 DQ/b  
} G#=b6DB  
catch(IOException e){e.printStackTrace ();} S3[oA&  
catch(Exception e){e.printStackTrace ();} 4h2bk\z-  
} sjg
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,'@ISCK^  
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//读取保存的下载信息（文件指针位置） ,\">ovV33  
private void read_nPos() k?_$h<Y  
{ R|
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try{ BtDgv.;GH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); r|sy_Sk/{  
int nCount = input.readInt(); @%okaj#IO  
nStartPos = new long[nCount]; c9TkIe  
nEndPos = new long[nCount]; >5YYij5Aj  
for(int i=0;i<nStartPos.length;i++) s!zr>N"  
{ @zpHemdB  
nStartPos = input.readLong(); m0K2p~  
nEndPos = input.readLong(); uc `rt"  
} ieK'<%dxF  
input.close(); -1Ki7|0,  
} z@40g)R2A  
catch(IOException e){e.printStackTrace ();} RI].LB_  
catch(Exception e){e.printStackTrace ();} Tr+Y@]"  
} L?pvz}  
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private void processErrorCode(int nErrorCode) ), x3tTR  
{ 1</t #r  
System.err.println("Error Code : " + nErrorCode); Zi'8~iEH  
} /:];2P6#X  
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//停止文件下载 Ay. q
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public void siteStop() 1F%*k &R  
{ b+fy&rk@-  
bStop = true; Sr-^f
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for(int i=0;i<nStartPos.length;i++) Sv[_BP\^h  
fileSplitterFetch.splitterStop(); XcW3IO  
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} 5L'@WB|{4u  
} fxCPGj  
//负责部分文件的抓取 5EZr"  
**FileSplitterFetch.java I2!&="7@  
*/ pPqbD}p  
package NetFox; hB1iSm  
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import java.io.*; BB}iBf I'  
import java.net.*; s#CEhb  
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public class FileSplitterFetch extends Thread { t@mw f3,  
5+PBS)pJ]%  
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String sURL; //File URL K0bmU(Xxp  
long nStartPos; //File Snippet Start Position ~V)VGGOL$v  
long nEndPos; //File Snippet End Position mCP +7q7  
int nThreadID; //Thread's ID +(hwe jyC  
boolean bDownOver = false; //Downing is over jfhDi6N  
boolean bStop = false; //Stop identical jF2GHyB  
FileAccessI fileAccessI = null; //File Access interface #pxet  
#hiDZ>nr  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h.0&)t\q"  
{ 0hr)tYW,G  
this.sURL = sURL; LGue=Hkp  
this.nStartPos = nStart; g{.@|;d<p  
this.nEndPos = nEnd; <\Dl#DH  
nThreadID = id; 8c'-eT"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |Szr=[  
} ~.=HN}E  
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public void run() 7o%|R2mL}  
{ [1X5r<(W5  
while(nStartPos < nEndPos && !bStop) Jywz27j  
{ \^Q)`Lqp:g  
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try{ Hm[!R:HW,S  
URL url = new URL(sURL); eyp\h8!u_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @Pg@ltUd  
httpConnection.setRequestProperty("User-Agent","NetFox"); bGLp
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String sProperty = "bytes="+nStartPos+"-"; >.sN?5}y  
httpConnection.setRequestProperty("RANGE",sProperty); z:? <aT  
Utility.log(sProperty); {dH<Un(4Z  
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InputStream input = httpConnection.getInputStream(); 3S21DC
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//logResponseHead(httpConnection); Q>Q}/{8!  
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byte[] b = new byte[1024]; sX?7`n1U  
int nRead; c7
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) SQ.Wj?W)  
{ \Xp"I5  
nStartPos += fileAccessI.write(b,0,nRead); 8x
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//if(nThreadID == 1) J
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 69w"$Vk  
} [wxI X  
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Utility.log("Thread " + nThreadID + " is over!"); zIm!8a  
bDownOver = true; &xT~;R^  
//nPos = fileAccessI.write (b,0,nRead); ZX}"  
} gx.]4v  
catch(Exception e){e.printStackTrace ();} 3Q"+ #Ob  
} [l{e
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} r\D8_S_  
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//打印回应的头信息 Gi2Ey37]O  
public void logResponseHead(HttpURLConnection con) RlL,eU$CS  
{ f.CI.
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for(int i=1;;i++) K?I&,t_*R  
{ x/^zNO\1  
String header=con.getHeaderFieldKey(i); vG}oo  
if(header!=null) ^@> Qiy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +Ea XS  
Utility.log(header+" : "+con.getHeaderField(header)); X Y?@
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else )o,0aGo>Of  
break; q{(&:~M  
} !Z)^

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} b DvbM  
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public void splitterStop() VG7#6)sQoK  
{ q,Q|Uvpk  
bStop = true; h}_q  
} {<n)zLy  
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1
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} tYa*%|!v  
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/* TD9`SSpP  
**FileAccess.java xUoY|$fI  
*//文件访问(定位，写) Sa~C#[V  
package NetFox; Wg&:xff  
import java.io.*; #{1fb%L{i  
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public class FileAccessI implements Serializable{ \]El%j4  
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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 g&wQ^  
RandomAccessFile oSavedFile; v,B\+q/  
long nPos; _Y=yR2O  
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public FileAccessI() throws IOException s9>!^MzBK  
{ S#dS5OX  
this("",0); }IL@j A
 
} Awh)@iTL  
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public FileAccessI(String sName,long nPos) throws IOException NR{:4zJT  
{ RJD3o_("K  
oSavedFile = new RandomAccessFile(sName,"rw"); W aU_Z/{0  
this.nPos = nPos; ;;5i'h~?]J  
oSavedFile.seek(nPos); \eCdGx?  
} AJu.  
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public synchronized int write(byte[] b,int nStart,int nLen) *Y~64FM  
{ Po3W+;@  
int n = -1; f_8~b0`  
try{ ZxQP,Ys_Y  
oSavedFile.write(b,nStart,nLen); 8b!_b2Za  
n = nLen; WTx;,TNG  
} L8Q!6oO=<  
catch(IOException e) Y`uCDfcQ  
{ (Bz(KyD[  
e.printStackTrace (); ).xWjVC  
} u!W00;`L  
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return n; 5"U7I{\  
} Sy~1U  
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} DP_\%(A  
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/* tP-
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**SiteInfoBean.java =_Rd0,  
*/ e<K=Q$U.  
package NetFox; }{J8U2])k  
_NFJm(X.  
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public class SiteInfoBean { +8M{y D9#  
~4 ab\hq  
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private String sSiteURL; //Site's URL 9tO_hhEQ@  
private String sFilePath; //Saved File's Path f&'md  
private String sFileName; //Saved File's Name -5K/ cK  
private int nSplitter; //Count of Splited Downloading File 2X`M&)"X  
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public SiteInfoBean() "2J;~  
{//nSplitter的缺省值为5 szHUHW~;J  
//default value of nSplitter is 5 4~4Hst#^  
this("","","",5); F<[8!^l(z  
} n^K]R}S  
bu- RU(%  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) m\yO/9{h1  
{ rGs> {-T3  
sSiteURL= sURL; 7+"X^$  
sFilePath = sPath; U N/.T   
sFileName = sName; aH_&=/-Tz  
this.nSplitter = nSpiltter; V.J%4&^X  
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/+u*9ZR&1  
} 9YKEME+:  
^^m%[$nw&r  
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public String getSSiteURL() ctGjqHo  
{ SDkN  
return sSiteURL; j^gF~Wz^  
} LHps2,  
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public void setSSiteURL(String value) J0IK=Y  
{ (
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sSiteURL = value; s=:n<`Z2  
} !s$fqn 6  
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public String getSFilePath() /bWV`*  
{ !E%!,  
return sFilePath; (<12&=WxE  
} w

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public void setSFilePath(String value) z,)Fvs4U.  
{ (H$eXW7  
sFilePath = value; \ys3&<;b  
} 2.6,c$2tB  
cMj<k8.{  
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public String getSFileName() #xmUND`@  
{ *jYwcW"R{z  
return sFileName; -&c@c@dC  
} {PU[MHZF  
k@w&$M{tPF  
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public void setSFileName(String value) #\}hN~@F  
{ X_h+\ 7N>  
sFileName = value; YXvKDw'95  
} V1ug.Jv^  
@wo9;DW`  
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public int getNSplitter() _u>+H#  
{ 8)i\d`  
return nSplitter; ,"D1!0  
} X**w
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6c2fqAF>i  
public void setNSplitter(int nCount) F?UL0Q|uv  
{ \1tce`+  
nSplitter = nCount; !%Ak15o  
} IflpM]  
} /fX]Yu  
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/* l6i 2!&8P%  
**Utility.java /(q*  
*/ 3}"VUS0wh  
package NetFox; <Sz9: hg-  
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public class Utility { b^v.FK46G  
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public Utility() (F @IUbnl  
{ ]Y3ALQr!  
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} ;G w5
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YXmLd'F^3  
//线程睡眠 f`?|A  
public static void sleep(int nSecond) P?bdjU#_n`  
{ 5f1yszd  
try{ QPBf++|  
Thread.sleep(nSecond); oL<^m?-u  
} 0hPm,H*Y]  
catch(Exception e) *QrTZ$\C  
{ Ngg (<ZN  
e.printStackTrace (); Cu0/TeEM  
} *{XbC\j  
} A>X#[qx  
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//日志 c^m}ep\F5L  
public static void log(String sMsg) /ZAEvdO*P  
{ " I:j a7  
System.err.println(sMsg); '06[@Cw  
} ,\Cy'TSz  
hGPjH=^EM  
S:Hg =|R  
public static void log(int sMsg) 9X!OQxmg  
{ ll6~8PN  
System.err.println(sMsg); (Y-
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} k+_pj k  
} uHy^ Bq  
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/* [~$9n_O94  
**TestMethod.java 42Z2Mjtk  
*/ J.~$^
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package NetFox; :[,n`0lH  
:c c#e&BO  
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public class TestMethod { {"O'kx  
si)920?E&  
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public TestMethod() =T9QmEBm  
{ ///xx/weblogic60b2_win.exe [03Aej  
try{ 1
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,b2Cl[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yY8q{\
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SiteFileFetch fileFetch = new SiteFileFetch(bean); ~Q5L)}8N  
fileFetch.start(); ao Y"uT+  
} ?FD^S~bz-  
catch(Exception e){e.printStackTrace ();} {]`O$S  
-$t#
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} `ez_ {  
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![ Fb~Egc  
public static void main(String[] args) 7n {uxE#U)  
{ 0z.Hl1  
new TestMethod(); $:SHZe  
} k/cQJz  
} ?PLf+S  
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