http断点续传简单实现（java)

/* HS(
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**SiteFileFetch.java N..9N$+(  
*/ ya:H{#%6  
package NetFox; * +OAc`8  
import java.io.*; .*Hv^_  
import java.net.*; tCc}}2bC&  
< "~k8:=4  
1d\K{ 7i#  
public class SiteFileFetch extends Thread { l_,8_u7G  
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SiteInfoBean siteInfoBean = null; //文件信息Bean A%Bz52yg  
long[] nStartPos; //开始位置 !^8'LMY<I  
long[] nEndPos; //结束位置 /f#rN_4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !kV?h5@Bo  
long nFileLength; //文件长度 ][?GJ"O+U  
boolean bFirst = true; //是否第一次取文件 o,aI<5"  
boolean bStop = false; //停止标志 .-W
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File tmpFile; //文件下载的临时信息 Uj!L:u2b  
DataOutputStream output; //输出到文件的输出流 &Q&$J )0  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >Zr/U!W*?  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q
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{ 8=2)I.   
siteInfoBean = bean; P AKh v.7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <?Lj!JGX  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x1Si&0T0P<  
if(tmpFile.exists ()) .0a$E`V=D  
{ f3596a  
bFirst = false; Q7DkhKT  
read_nPos(); Xt7uCs  
} eA+6-'qN  
else tGf  
{ 5|>jz `  
nStartPos = new long[bean.getNSplitter()]; (TY^ kySr  
nEndPos = new long[bean.getNSplitter()]; Ql\GL"  
} FijzO  
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} 3F4I{L  
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@|cas|U.r  
public void run() c3Mql+@  
{ f|< *2Mk  
//获得文件长度 H~$a6T"&  
//分割文件 +q=/}|  
//实例FileSplitterFetch Qp<6qM35  
//启动FileSplitterFetch线程 )fC^h=Qp  
//等待子线程返回 QzV:^!0J  
try{ )9PQj  
if(bFirst) |\b*p:el  
{ lJKU^?4S8  
nFileLength = getFileSize(); $Itehy  
if(nFileLength == -1) zx\?cF  
{ >Vg<J~[
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System.err.println("File Length is not known!"); bx5X8D  
} \Mi y+<8$  
else if(nFileLength == -2) ?p}m[9@  
{ 2>UyA.m0  
System.err.println("File is not access!"); BGUP-_&  
} Z$+0gm\Cnw  
else ft$/-;  
{ +='.uc_  
for(int i=0;i<nStartPos.length;i++) QRa>W/N  
{ )TP7gLv=b  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); M#2DI?S@  
} tTP"*Bb  
for(int i=0;i<nEndPos.length-1;i++) *%Q!22?6F  
{ ~xzRx$vU  
nEndPos = nStartPos[i+1]; QPdhesr
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} zQD$+q5h  
nEndPos[nEndPos.length-1] = nFileLength; zf6k%  
} $%sOL( r  
} 3VKArv-  
7zy6`OP  
)Ibp%'H  
//启动子线程  &grT}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; A<AZs~f  
for(int i=0;i<nStartPos.length;i++) VBs
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{ !7Ta Vx}`(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ULAAY$o@5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Uln[UK  
nStartPos,nEndPos,i); RV7l=G9tq  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rFdovfb   
fileSplitterFetch.start(); a B%DIH,  
} p]IF=~b  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IU/dY`J1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); BEN=/ v  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Xb3z<r   
nEndPos = " + nFileLength); $^
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// fileSplitterFetch[nPos.length-1].start(); RCo!sZP}  
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1Y\g{A"  
//等待子线程结束
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//int count = 0; t%V!SvT8+  
//是否结束while循环 j8L!miv6  
boolean breakWhile = false; 4tof[n3us  
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while(!bStop) %sbDH  
{ TE3A(N'  
write_nPos(); 8|OsVIe%  
Utility.sleep(500); ;1A4p`)  
breakWhile = true; w?Cqe N  
^#9 &Rk!t  
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for(int i=0;i<nStartPos.length;i++) ZM`6zS!  
{ xJ:15eDC  
if(!fileSplitterFetch.bDownOver) &2d^=fih  
{ NVAt-u0LB  
breakWhile = false; R6r'[-B2  
break; # 4L[8(+V  
} odD^xg"L  
} #qtAFIm'  
if(breakWhile) $0~H~-  
break; K?8{y
 
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//count++; ~k'KS 7c  
//if(count>4) & gnE"  
// siteStop(); `lX |yy"  
} AK]{^Hv
z  
@`^+XPK\  
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System.err.println("文件下载结束！"); y0k*iS e  
} 8*-8"It<"  
catch(Exception e){e.printStackTrace ();} !o1{. V9q  
} ,u8)g;8s  
ze@NqCF  
X
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//获得文件长度 >RZ]t[)y  
public long getFileSize() ViIt'WX  
{ (n_lu=E70  
int nFileLength = -1; [DpGL/Y.  
try{ qpjtF'  
URL url = new URL(siteInfoBean.getSSiteURL()); Ab ,n^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >>oR@  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y&!M#7/'J3  
i`U:uwW`  
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int responseCode=httpConnection.getResponseCode(); 6A&e2K>A  
if(responseCode>=400) `?r]OVe{y  
{ $<cio X  
processErrorCode(responseCode); HI)MBrj;r  
return -2; //-2 represent access is error 3C'`K,
  
} |U)m'W-(q  
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String sHeader;  O_^O1  
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for(int i=1;;i++) swNJ\m  
{ $.{CA-~%[  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); v0hr~1  
//Utility.log(in.readLine()); ]AkHNgW  
sHeader=httpConnection.getHeaderFieldKey(i); banie{ e  
if(sHeader!=null) C/V{&/5w  
{ Dlz||==  
if(sHeader.equals("Content-Length")) .I\)1kjX  
{ eLE9-K+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); vl59|W6  
break; B~zP!^m  
} E/ %S0  
} v\7k  
else {.F``2  
break; ;m6Mm`[i
<  
} EGMj5@>  
} GBOz,_pw  
catch(IOException e){e.printStackTrace ();} ;4.D%  
catch(Exception e){e.printStackTrace ();} dv3+x\`9  
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/?X1>A:*  
Utility.log(nFileLength); Cr0 \7  
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return nFileLength; +
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}  /;LteBoY  
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U  
OdX-.FFl  
//保存下载信息（文件指针位置） G"!YV#"~  
private void write_nPos() *]G&pmMs  
{ AMqu}G  
try{ R<W#.mpo6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); w`XwW#!}@$  
output.writeInt(nStartPos.length); 7kpCBLM(}  
for(int i=0;i<nStartPos.length;i++) xo{f"8}^  
{ 
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// output.writeLong(nPos); E\!:MCL  
output.writeLong(fileSplitterFetch.nStartPos); G3QB Rh{  
output.writeLong(fileSplitterFetch.nEndPos); u:H@]z(x  
} L^PZ\OC  
output.close(); X'N4a  
} t!^FWr&  
catch(IOException e){e.printStackTrace ();} $hB;r  
catch(Exception e){e.printStackTrace ();} j}YZl@dYV  
} 5r/QPJ<h  
2cfzLW(  
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//读取保存的下载信息（文件指针位置） h`&@>uEiq  
private void read_nPos() g#FqjE|mx  
{ 6$wS7Cu  
try{ vj0`[X   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ><iEVrpN  
int nCount = input.readInt(); (\FjbY9&  
nStartPos = new long[nCount]; e1{t qNJ  
nEndPos = new long[nCount]; [ d<|Cde  
for(int i=0;i<nStartPos.length;i++) Vja' :i  
{ THQW8 V  
nStartPos = input.readLong(); +Cx~4zEq  
nEndPos = input.readLong(); "d'xT/l "  
} l1`Zp9I  
input.close(); OB3AZH$  
} *sf9(%j  
catch(IOException e){e.printStackTrace ();} U0u@[9!  
catch(Exception e){e.printStackTrace ();} W"Dj+/uS  
} Q"8)'dL'  
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private void processErrorCode(int nErrorCode) [
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{ !_<.6ja  
System.err.println("Error Code : " + nErrorCode); do*`-SDy  
} 'N='B<^;%  
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//停止文件下载
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public void siteStop() Cd#*Wp)s  
{ SiojOH  
bStop = true; u!g=>zEu  
for(int i=0;i<nStartPos.length;i++) &m8B%9w  
fileSplitterFetch.splitterStop(); %H<w.]>  
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<Q\`2{  
} UkNC|#l)  
} $$ _uQf  
//负责部分文件的抓取 iBJ*6or
z  
**FileSplitterFetch.java DJ}xD&G  
*/ %9mB4Fc6b)  
package NetFox; ygpC1nN  
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import java.io.*; 1:YDN.*  
import java.net.*; l0D.7>aj  

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public class FileSplitterFetch extends Thread { [%l+ C~m  
]CC~Eo-%-  
G&C)`};  
String sURL; //File URL .e.vh:Sz  
long nStartPos; //File Snippet Start Position QH\*l~;B\  
long nEndPos; //File Snippet End Position " "a+Nc  
int nThreadID; //Thread's ID qwFn(pK[  
boolean bDownOver = false; //Downing is over A9l^S|r  
boolean bStop = false; //Stop identical Arp4$h  
FileAccessI fileAccessI = null; //File Access interface 3%EwA\V(  
3;:xEPb._6  
{7/6~\'/@  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException UO:>^,(j  
{ GUN<ZOYb=  
this.sURL = sURL; +#B%YK|LR  
this.nStartPos = nStart; (/*-M]>  
this.nEndPos = nEnd; e:7aVOm  
nThreadID = id; |um)vlN;9  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qA30z%#z_  
} r1?LKoJOn  
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public void run() HKxrBQr78  
{ T3?kabbF  
while(nStartPos < nEndPos && !bStop) ~{NDtB)  
{ D1g1"^~g  
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W}=2?vHV=  
try{ wy-!1wd  
URL url = new URL(sURL); uPo>?hpq+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,~4(td+R7  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0?`#ko7~d  
String sProperty = "bytes="+nStartPos+"-"; 15s?QSKj  
httpConnection.setRequestProperty("RANGE",sProperty); Bf* F^  
Utility.log(sProperty); 3=K-+dhk|t  
}oU&J81  
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InputStream input = httpConnection.getInputStream(); H{$yy)@F  
//logResponseHead(httpConnection); }}xR?+4A  
8'quQCx*=  
< 1r.p<s  
byte[] b = new byte[1024]; T(}da**X  
int nRead; y\)w#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;kFp)*i  
{ ;
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nStartPos += fileAccessI.write(b,0,nRead); bQ4 }no0  
//if(nThreadID == 1) ]fc:CR  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :Oj+Tc9A  
} h}d7M55#|  
JjCf<ktE.  
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Utility.log("Thread " + nThreadID + " is over!"); }B.C#Y$@  
bDownOver = true; ?=G H{ %E  
//nPos = fileAccessI.write (b,0,nRead); Y\=:j7'  
} Z`!pU"O9l  
catch(Exception e){e.printStackTrace ();} 9c6V&b  
} `fRy"44nR  
} 6]3ZUH;  
h^c'L=dR  
+Oscy-;  
//打印回应的头信息 j AE0$u~.  
public void logResponseHead(HttpURLConnection con) 93dotuF  
{ r]S9z  
for(int i=1;;i++) &Y>u2OZ  
{ vqHJc2yYkZ  
String header=con.getHeaderFieldKey(i); vOS0E^  
if(header!=null) >tzXbmFp;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); nXS%>1o,  
Utility.log(header+" : "+con.getHeaderField(header)); P:TpB6.=q  
else KWUz]>Z  
break; Ed-gYL^<  
} a8 1%M  
} #Q"vwek  
( A)wcB  
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public void splitterStop()
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{ v\eBL&WK  
bStop = true; B@=<'/S\7  
} :I('xVNPz  

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#77UKYj2L-  
} *PEuaRDN  
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/* `[CJtd2\  
**FileAccess.java 81cmG`G7  
*//文件访问(定位，写) j%;)CV G"  
package NetFox; xW =$j|  
import java.io.*; @45H8|:k  
!&lPdEc@T  
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public class FileAccessI implements Serializable{ #pSOZX  
836m5/kH[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 fJ2{w[ne  
RandomAccessFile oSavedFile; SZ{cno1`  
long nPos; |sa7Y_  
9 Zm<1Fw  
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public FileAccessI() throws IOException zDyeAxh4  
{ _kN%6~+U  
this("",0); :, [!8QP  
} PAV2w_X~  
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>-lL-%N_  
public FileAccessI(String sName,long nPos) throws IOException "NH+qQhs  
{ yQ{_\t1Wd  
oSavedFile = new RandomAccessFile(sName,"rw"); 0t?<6-3`/  
this.nPos = nPos; ~@b}=+n  
oSavedFile.seek(nPos); T zYgH  
} y=xe<#L  
)]> '7] i  
Q 02??W  
public synchronized int write(byte[] b,int nStart,int nLen) &W+G{W{3  
{ xKST-:c+  
int n = -1; zl 0^EltiU  
try{ KH>sCEt  
oSavedFile.write(b,nStart,nLen); !9LAXM  
n = nLen; F>kn:I"X)  
} ?>jA
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catch(IOException e) /{MH'  
{ 2G5!u
)  
e.printStackTrace (); 1=5'R/k  
} j_uY8c>3\q  
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a 8hv.43  
return n; _AHB|P I  
} T>Rf?%o  
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} \Bc
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/* IcA\3j  
**SiteInfoBean.java 9 roth  
*/ pF*~)e  
package NetFox; LOUKUReE  
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>`?+FDOJ,  
public class SiteInfoBean { h:Mn$VR,  
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}Oh'YX#[  
private String sSiteURL; //Site's URL ^AjYe<RU}  
private String sFilePath; //Saved File's Path 9q)nNX<$)  
private String sFileName; //Saved File's Name tTh;.8
8Z{  
private int nSplitter; //Count of Splited Downloading File @uM3iO7&
 
t
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public SiteInfoBean() yZ~eLWz  
{//nSplitter的缺省值为5 vb.Y8[  
//default value of nSplitter is 5 s?;<F  
this("","","",5); &~JfDe9IS  
} ]^6y NtLK  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) voej ~z+  
{ 6[3Ioh  
sSiteURL= sURL; CMxjX  
sFilePath = sPath; T.
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sFileName = sName; kq}eUY]  
this.nSplitter = nSpiltter; ,ORG"]_F  

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} WVT5VJ7*  
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At
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public String getSSiteURL() C`th^dqBV  
{ ! N"L`RWD  
return sSiteURL; 2c>H(t h=  
} ;LF)u2x=  
gcW{]0%L^  
C>`.J_N  
public void setSSiteURL(String value) N9JgV,`  
{ ),y!<\oQ  
sSiteURL = value; XC/]u%n8](  
} T?]kF-   
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public String getSFilePath() S`2mtg  
{ \{MrQ2jd  
return sFilePath; gM
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} L%o65  
@^:7UI_  
9OQ0Yc!3  
public void setSFilePath(String value) EYJi6#  
{ T)Zt'M  
sFilePath = value; 7S dV%"  
} %];h|[ax]  
g@k#J"Q'[  
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public String getSFileName() Q0L@.`~  
{ }4\!7]FVYX  
return sFileName; L&DF,fWsF&  
} 68J 9T^84  
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}o!#_N0T  
public void setSFileName(String value) !HdvCYB>  
{ 4(Cd  
sFileName = value; MR?*GI's  
} cz7CrK~5  
_[$T29:8\]  
j*eUF-J1  
public int getNSplitter() XoKO2<3  
{ 5M<'A=  
return nSplitter; /slm ]'  
} L= :d!UF  
`FzYvd"N  
FUyB
"-<  
public void setNSplitter(int nCount) "W &:j:o  
{ m?D <{BQ;  
nSplitter = nCount; Sc4obcw%  
} q3AJwELXw  
} [5?4c'Ev  
`j&0VIU>>  
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/*  (kWSK:l  
**Utility.java |+Hp+9J  
*/ sJ))<,e5I  
package NetFox; vU_d=T%$  
T3USNc51  
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public class Utility { aN^]bs?R  
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public Utility() ||-nmOy  
{ v229H<  
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]{f^;y8  
} di6B!YQP  
CS/Mpmsp  
//线程睡眠 ;y>S7n>n:  
public static void sleep(int nSecond) H~A"C'P3#  
{ Tub1Sv>J  
try{ yfmp$GO:  
Thread.sleep(nSecond); s kN9O"^A  
} D(y+1^>  
catch(Exception e) Q~Ay8L+  
{ j$3rJA%rN  
e.printStackTrace (); ~I{EE[F>qL  
} c |>=S)|  
} BjJ,"sT  
,N53Iic  
//日志
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public static void log(String sMsg) F%xK"l`&  
{ "(s6aqO$  
System.err.println(sMsg); ')B =|T)  
} J,f/fPaf7  
10p8|9rE}B  
6X/wdk  
public static void log(int sMsg) "jMqt9ysN  
{ 7ftR4  
System.err.println(sMsg); ~12_D'8D[  
} MkwU<ae AB  
} n.*3,4.]  
9A~>`.y
 
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/* 4SgF,ac3r  
**TestMethod.java JIzY,%`\  
*/ eP"`,<  
package NetFox; 5iVQc-m&  
3UdU"d[75  
)zU:  
public class TestMethod { z v>Oh#  
e@
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?WQNIX4  
public TestMethod() 5F2_xH$5  
{ ///xx/weblogic60b2_win.exe av-#)E  
try{ F/>*Ifs  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]4`t\YaT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); gH[,Xx?BN!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); kY"KD22a  
fileFetch.start(); s=Df `  
} OOnX`  
catch(Exception e){e.printStackTrace ();} H3, ut  
t2- ^-g6  
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} ciudRK63M  
%%%S"$t  
?7 \\e;j}  
public static void main(String[] args) jfD1  
{ ]IZ>2!6r
  
new TestMethod(); /`[!_4i  
} v!9i"@<!  
} >O#grDXb  
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