http断点续传简单实现（java)

/* oJ0ZZu?{D  
**SiteFileFetch.java QG;V\2T2[  
*/ )'$'?Fn  
package NetFox; IoHYY:[-  
import java.io.*; -W1Apd%>  
import java.net.*; ()(/9t  
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~J|B  
public class SiteFileFetch extends Thread { KU87WpjX  
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SiteInfoBean siteInfoBean = null; //文件信息Bean p</V_BIW  
long[] nStartPos; //开始位置 Iv>4o~t  
long[] nEndPos; //结束位置 u 9kh@0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 JS(%:  
long nFileLength; //文件长度 lXu6=r  
boolean bFirst = true; //是否第一次取文件 :v8~'cZ  
boolean bStop = false; //停止标志 $`|\aXd[C*  
File tmpFile; //文件下载的临时信息 >8w=Vlp  
DataOutputStream output; //输出到文件的输出流 GFYHt!&[\  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）

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public SiteFileFetch(SiteInfoBean bean) throws IOException h@D!/PS  
{ PKX Tj6hj)  
siteInfoBean = bean; mP-Y9*k  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); rjw
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); HH7Bg0=(  
if(tmpFile.exists ()) 4inMd![  
{ e!1am%aE  
bFirst = false; KqzQLu  
read_nPos(); T7ICXpe@  
} hixG/%aO  
else RH0J#6C/  
{
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nStartPos = new long[bean.getNSplitter()]; &z;
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nEndPos = new long[bean.getNSplitter()]; ,<]~/5-f  
} =~'{2gsB  
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} n~?n+\.&a  
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public void run() Tu}?Q.pKo  
{ &K-0ld(;  
//获得文件长度 G[a&r   
//分割文件 [>LL  
//实例FileSplitterFetch sx@%3j  
//启动FileSplitterFetch线程 FYX"q-Z  
//等待子线程返回 c"`CvQO64  
try{ _|s'0F/t  
if(bFirst) {M P(*N  
{ e c4vX  
nFileLength = getFileSize(); XjU/7Q  
if(nFileLength == -1) ^,6c9Dxy  
{ }"6 PM)s  
System.err.println("File Length is not known!"); +YCKd3/  
} yFjjpEpnFt  
else if(nFileLength == -2) "D7wt
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{ 50NLguE  
System.err.println("File is not access!"); i5Dq'wp  
} ]O+W+h{]  
else b' fcWp0  
{ 2#xz,RM.  
for(int i=0;i<nStartPos.length;i++) xA]}/*  
{ O <"\G!y~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N:&EFfg3  
} >\ x!a:}  
for(int i=0;i<nEndPos.length-1;i++) a0 8Wt  
{ ! ^TCe8  
nEndPos = nStartPos[i+1]; tY!GJusd  
} bTW# f$q:4  
nEndPos[nEndPos.length-1] = nFileLength; RKO} W#?  
} _REAzxeS  
} l1ViUY&Z  
Z:Y_{YAD  
}MW+K&sIh  
//启动子线程 xw~3x*{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D> EN:_v  
for(int i=0;i<nStartPos.length;i++) .[C@p`DZ  
{ ,]_<8@R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p\ _&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), T!Z).PA#  
nStartPos,nEndPos,i); o'Kl+gw4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0c$ ')`!m  
fileSplitterFetch.start(); 8;"HM5+  
} YzeNr*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ID8u&:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); U\x$@J  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2su/I  
nEndPos = " + nFileLength); WADAp\&  
// fileSplitterFetch[nPos.length-1].start(); ){$*<#&H  
S$ Z?T  
}ISc^W) t  
//等待子线程结束 VrnZrQj<  
//int count = 0; Ktn:6=,  
//是否结束while循环 #-8%g{  
boolean breakWhile = false; pra0:oHN  
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while(!bStop) cE+Y#jB  
{ IT:8k5(L5j  
write_nPos(); G:i>MJbxT  
Utility.sleep(500); rIQ%X`Y  
breakWhile = true; D/bF  
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for(int i=0;i<nStartPos.length;i++) K2!GpGZu  
{ qw6i|JM%  
if(!fileSplitterFetch.bDownOver) _DLELcH Y  
{ 0rCQz3gh1  
breakWhile = false; pI1IDu*_Z  
break; fHiS'R  
} v^3s?VD  
} YWF Hv@  
if(breakWhile) X|dlVNL8p  
break; NY"+Qw@$  
< %{?Js  
;2[o>73F  
//count++; hkl9EVO)  
//if(count>4)  SGK 5  
// siteStop(); =;~*YD(%/  
} #R*7y%cO  
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System.err.println("文件下载结束！"); (Q}ByX  
} usR+ZQaA  
catch(Exception e){e.printStackTrace ();} c;.jo?RR2  
} 4n6t(/]b<  
a7n`(}?Y  

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//获得文件长度 vE&K!k`  
public long getFileSize() t_w2J=2  
{ dQ=L<{(  
int nFileLength = -1; )LTX.Kg  
try{ V)A7q9Bum  
URL url = new URL(siteInfoBean.getSSiteURL()); xv~Sk2Z+d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rr]-$]Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); p9![8VU  
8,-U`.  
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int responseCode=httpConnection.getResponseCode(); -S7i':  
if(responseCode>=400) O'h f8w  
{ dF$&fo%  
processErrorCode(responseCode); ;e0-FF+  
return -2; //-2 represent access is error TGHyBPJb  
} (Rh$0^)A  
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String sHeader; A$70!5*  
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for(int i=1;;i++) {'sp8:$a  
{ %\T#Ik~3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); m\G
45%m  
//Utility.log(in.readLine()); #@L5yy2  
sHeader=httpConnection.getHeaderFieldKey(i); 1|:'jK#gE  
if(sHeader!=null) /<1zzeHRSD  
{ +h@ZnFp3  
if(sHeader.equals("Content-Length")) oc;4;A-;`c  
{ DO6 pv  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xM=?ES  
break; Jk;dtLL}4  
} QXEz  
} Y2[ik<  
else !GnwE  
break; g[N3jt@  
} TjicltQi4  
} X}g"_wN,g>  
catch(IOException e){e.printStackTrace ();} W:hTRq  
catch(Exception e){e.printStackTrace ();} 2`J#)f|  
('Ha$O72  
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Utility.log(nFileLength); M)3'\x:  
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return nFileLength; /sr.MT
 
} Yf_/c*t\5  
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d)GR]^=r  
//保存下载信息（文件指针位置） 5E^P2Mlc  
private void write_nPos() (dwb{+HW  
{ pgPm0+N  
try{ E+cx8(   
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8>`8p0I$+  
output.writeInt(nStartPos.length); \%_sL#?  
for(int i=0;i<nStartPos.length;i++) b%7zu}F  
{ b9VI(s>  
// output.writeLong(nPos); ;?C`Jagx  
output.writeLong(fileSplitterFetch.nStartPos); Q w)U  
output.writeLong(fileSplitterFetch.nEndPos); w5=<}1`St  
} )JY#8,{w  
output.close(); d2fiPI7lg  
} ;@qQ^!g2  
catch(IOException e){e.printStackTrace ();} ^%O$7*  
catch(Exception e){e.printStackTrace ();} <Ok7-:OxA  
} }U?:al/m  
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[9yd29pQ]  
//读取保存的下载信息（文件指针位置） ]e$n;tuW  
private void read_nPos() 9<.8mW^68  
{ ?}HZJ@:lB  
try{ G"ixw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0-p %.}GE  
int nCount = input.readInt(); 5t|$Yt[  
nStartPos = new long[nCount]; LI>Bl  
nEndPos = new long[nCount]; <?%49  
for(int i=0;i<nStartPos.length;i++) :XOjS[wBm  
{ %4})_h?j  
nStartPos = input.readLong(); KQ0f2?  
nEndPos = input.readLong(); >:h&5@^j$  
} lQxEiDIL  
input.close(); ra8AUj~RX  
}
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catch(IOException e){e.printStackTrace ();} h-fm)1S_  
catch(Exception e){e.printStackTrace ();} 3;88a!AA!  
} P MI?PC[;  
:s1.TQ;Y(  
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private void processErrorCode(int nErrorCode) Y.kc,~vYL  
{ 'sTc=*p/  
System.err.println("Error Code : " + nErrorCode); \F
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} JOyM#g9-?  
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=  
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//停止文件下载 2OjU3z<J  
public void siteStop() "
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{ `Om W#\  
bStop = true; u Yc}eMb  
for(int i=0;i<nStartPos.length;i++) O&sUPv  
fileSplitterFetch.splitterStop(); ^!$=(jh.  
n`!6EaD  
8mt#S  
} &3SmTg %  
} H9Vn(A8&`  
//负责部分文件的抓取 `JyI`@,!  
**FileSplitterFetch.java ^CD?SP"i  
*/ ^S 45!mSb  
package NetFox; I8|"h8\  
> w SI0N  
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import java.io.*; ]Bs{9=2  
import java.net.*; FGeKhA 8jT  
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public class FileSplitterFetch extends Thread { /N,\st  
[fY7|  
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String sURL; //File URL CZ>Ujw=&k  
long nStartPos; //File Snippet Start Position TP/bX&bjCy  
long nEndPos; //File Snippet End Position nRT]oAi  
int nThreadID; //Thread's ID !_oR/)  
boolean bDownOver = false; //Downing is over (M{>9rk8  
boolean bStop = false; //Stop identical OGO\u#
  
FileAccessI fileAccessI = null; //File Access interface 4UND;I&  
[;UI8Stw  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }PM7CZSq  
{ 5W=Jn?y2  
this.sURL = sURL; yCkX+{ki  
this.nStartPos = nStart; Bn.5ivF3  
this.nEndPos = nEnd; 6$l?D^{  
nThreadID = id; 24wr=5p]Q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 QZ[S, c^  
} L-zU%`1{M  
$LcMG,8%_  
}}bMq.Q'  
public void run() =J]M#6N0  
{ d(9-T@J  
while(nStartPos < nEndPos && !bStop) AUES;2WL  
{ Ul3xeu  
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/ %iS\R%ca  
try{ riRG9c |  
URL url = new URL(sURL); lXEnm-_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;|W:,a{kS  
httpConnection.setRequestProperty("User-Agent","NetFox"); qn'TIE.  
String sProperty = "bytes="+nStartPos+"-"; ab#z&jg!  
httpConnection.setRequestProperty("RANGE",sProperty); P@%L.y B  
Utility.log(sProperty); 4UK>Vzn  
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InputStream input = httpConnection.getInputStream(); t_Rj1U  
//logResponseHead(httpConnection); JB=L{P J  
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byte[] b = new byte[1024]; `u_k?)lK  
int nRead;
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 87m`K Str7  
{ Wtp=1  
nStartPos += fileAccessI.write(b,0,nRead); #%L_wJB-  
//if(nThreadID == 1) o/[Ks;l  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =NSunW!  
} d(Hqj#`-31  
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Utility.log("Thread " + nThreadID + " is over!"); =W>a~e]/  
bDownOver = true; <fA}_BH%]  
//nPos = fileAccessI.write (b,0,nRead); ltMcEv-d0  
} 0QxBC7`qp  
catch(Exception e){e.printStackTrace ();} &}K%F)S  
} if3z Fh  
} }J2f$l>R  
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//打印回应的头信息 {xOzxLB;  
public void logResponseHead(HttpURLConnection con) }SyK)W5Y  
{ THB[(3q  
for(int i=1;;i++) zU!d(ge.E  
{ 7!)VOD8Z  
String header=con.getHeaderFieldKey(i); PYzTKjw  
if(header!=null) [xQ.qZ[h&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Qstd;qE~  
Utility.log(header+" : "+con.getHeaderField(header)); ln":j?`  
else @ScC32X  
break; O1+yOef"k  
} 3(gOF&Uf9  
} +_QcLuV,  
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public void splitterStop() g@pK9R%wH<  
{ J HV  
bStop = true; Q'?VLv|@  
} $ f||!g  
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} woF{O)~X  
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/* DF-.|-^9I  
**FileAccess.java B}K<L\S  
*//文件访问(定位，写) J,s:CBCGL  
package NetFox; FMzG6nrdBN  
import java.io.*; 6&L;Sw#Dg  
NbCIL8f]  
3df5 e0  
public class FileAccessI implements Serializable{ '-$cvH7_  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 I]3!M`IMG  
RandomAccessFile oSavedFile;
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long nPos; @W~aoq6  
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public FileAccessI() throws IOException ^upd:q  
{ ,f<J4U:Y  
this("",0); jM-5aj[K  
} H ]!P[?  
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public FileAccessI(String sName,long nPos) throws IOException 77wod}h!:  
{ ,DEcCHr,  
oSavedFile = new RandomAccessFile(sName,"rw"); 563ExibH  
this.nPos = nPos; N^k& 8  
oSavedFile.seek(nPos); QjYw^[o  
} v yt|x5  
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public synchronized int write(byte[] b,int nStart,int nLen) aSgKh  
{ rEbH<|  
int n = -1; .'h^  
try{ ub+XgNO  
oSavedFile.write(b,nStart,nLen); &5G@YQD1e  
n = nLen; q]*jT
b  
} cmq4w&x/  
catch(IOException e) e-1G\}E  
{ 'q RQO(9&m  
e.printStackTrace (); +oHbAPs8  
} ou`KkY||  
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return n; oMOh4NH,x  
} /}iBrMD{[  
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} nHp(,'R/  
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/* 4gUx#_AaG  
**SiteInfoBean.java "/2kf)l{4  
*/ hb
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package NetFox; @ `mke4>_  
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public class SiteInfoBean { <aI}+  
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private String sSiteURL; //Site's URL (v? rZv  
private String sFilePath; //Saved File's Path B7'yc`)H  
private String sFileName; //Saved File's Name Q&"oh  
private int nSplitter; //Count of Splited Downloading File y0/FyQs  
9]1LwX!M2  
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public SiteInfoBean() #EB Rc4>,  
{//nSplitter的缺省值为5 |`V=hqe{  
//default value of nSplitter is 5  !$!%era`  
this("","","",5); iM6(bmc.  
} dO,;k+  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]<r.{EJ  
{ {zLgLBM  
sSiteURL= sURL; ^!n|j]aw  
sFilePath = sPath; _={mKKoHs  
sFileName = sName; 6:`[Fi  
this.nSplitter = nSpiltter; &2O~BIRE  
>m{>0k(^`  
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} 'iDkAmvD  
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y=[{:
 
public String getSSiteURL() h(4\k?C5  
{ jpoNTl'  
return sSiteURL; {LCKt/Z>P  
} x~{W(;`!  
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public void setSSiteURL(String value)  x\VP X  
{ bka%W@Y%  
sSiteURL = value; Fdq5:v?k  
} !C^>
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oEj$xm_}  
public String getSFilePath() x-4d VKE*z  
{ B7.&yXWgn  
return sFilePath; +Z"[2Dm  
} 4Mt
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3a=\$x@  
public void setSFilePath(String value) LX=v _}l J  
{ s~o\j/  
sFilePath = value; 0<fQjXn  
} BlcsDB =ka  
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~@[<y1g?nG  
public String getSFileName() uss!E!_%,  
{ >$=l;jO`n  
return sFileName; xh!T,|IR  
} Gm0}
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public void setSFileName(String value) h|lH`m^  
{ kXlI*h  
sFileName = value; \|M[W~
8  
} z3>4 xn{  
ap
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public int getNSplitter() u),.q7(m  
{ 5l%g3F  
return nSplitter; }Gx@1)??  
} ]k+(0qxG  
U%;E:|  
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public void setNSplitter(int nCount) D*sL&Rt][Y  
{ EV
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nSplitter = nCount; Bqb`WX[<`  
} 'R42N3|F  
} zvdIwV&oT  
, E$f"  
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/* i<=2 L?[.I  
**Utility.java 6
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*/ Z J1
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package NetFox; !:tr\L {  
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public class Utility { cjd-B:l  
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public Utility() ~d ~oC$=TC  
{ G{Uqp
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A6   
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} ?@MWV  
&!HG.7AY  
//线程睡眠 6q `Un}  
public static void sleep(int nSecond) HsT6 #K  
{ %kgT=<E'  
try{ j_0l'Saj  
Thread.sleep(nSecond); m#RMd,'X  
} Xr88I^F;  
catch(Exception e) :&2%x  
{ 1Oak8 \G  
e.printStackTrace (); R"\(a  
} dX[Xe  
} ;4Xx5*E  
r/HG{XH`  
//日志 K2V?[O#  
public static void log(String sMsg) t?=V<Yd1  
{ 4\uq$.f-  
System.err.println(sMsg); $~?)E;S  
} ^v:XON<  
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lTtc#  
public static void log(int sMsg) C+mPl+}w  
{ D}-HWJQA3  
System.err.println(sMsg); P4c}@Mq3  
} !FB2\hiM  
} 1CV?  
9[`\ZGWD  
XIl#0-E0X  
/*
{>TAnb?n  
**TestMethod.java x`'s  
*/ A.r.tf}:  
package NetFox; m2ph8KC  
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:?i,!0#"  
public class TestMethod { F*NHy.Y  
(/t{z=  
vy>(?[  
public TestMethod() gT,iH.  
{ ///xx/weblogic60b2_win.exe r]wy-GT  
try{ -OKXfN]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q 1u_r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >N}+O<Fc  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <xH! Yskc  
fileFetch.start(); 3Gw*K-.  
} C/ ]Bx  
catch(Exception e){e.printStackTrace ();} ;$qc@)Uwp  
AU9:Gu@M/  

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} H$ :BJ$x@  
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*)HVK&'  
public static void main(String[] args) F`+S(APT8  
{ [DTe
  
new TestMethod(); F:.8O ,%u  
} !9j6l0  
} *0r!eD   
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