http断点续传简单实现（java)

/* GS3ydN<v  
**SiteFileFetch.java '17u W
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*/ XfT6,h7vFL  
package NetFox; L3~E*\cV  
import java.io.*; .ODtduURe  
import java.net.*; =;$&:Zjy/%  
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public class SiteFileFetch extends Thread { hTn }AsfLY  
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SiteInfoBean siteInfoBean = null; //文件信息Bean a~~"2LE`  
long[] nStartPos; //开始位置 /a
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long[] nEndPos; //结束位置 {UYqRfgbZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 uyG4zV\h*  
long nFileLength; //文件长度 $P@P}%2  
boolean bFirst = true; //是否第一次取文件 e"|9%AW@<  
boolean bStop = false; //停止标志 |R*fw(=W  
File tmpFile; //文件下载的临时信息 _H8)O2mJ  
DataOutputStream output; //输出到文件的输出流 +o/;bm*U<K  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1|cmmUM-'v  
public SiteFileFetch(SiteInfoBean bean) throws IOException u-k?ef  
{ {+t'XkA  
siteInfoBean = bean; ~ab"q%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); oci-[CI,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9HEc=,D|  
if(tmpFile.exists ()) 95
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{ %r!  
bFirst = false; LZ ID|
-  
read_nPos(); >)pwmIn<  
} W3 8=fyD  
else qW<: `y  
{ {YbqB6zaM  
nStartPos = new long[bean.getNSplitter()]; M3F8@|2  
nEndPos = new long[bean.getNSplitter()]; a<gzI  
} n(f&uV_):  
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} 65J'uN  
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public void run() *}w.xt  
{ c@q>5fR/c  
//获得文件长度 l2`8]Qr   
//分割文件 T)Nis~  
//实例FileSplitterFetch 9 [I ro  
//启动FileSplitterFetch线程 #t(?8!F  
//等待子线程返回 a*IJ)'S  
try{ G(0bulq  
if(bFirst) j^!J:Bj  
{ ) L{Tn8  
nFileLength = getFileSize(); {U(h]'  
if(nFileLength == -1) $uLzC
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{ VBCj.dw  
System.err.println("File Length is not known!"); QX]tD4OH  
} (I~,&aBr  
else if(nFileLength == -2) m#;:%.Rm  
{ MA-$aN_(  
System.err.println("File is not access!"); "?9fL#8f*!  
} $qrr]U  
else sy@k3wQ  
{ bo -Gh`  
for(int i=0;i<nStartPos.length;i++) y?unI~4tC  
{ 7T2W%JT-,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "+Qh,fTt  
} #/jHnRrQ   
for(int i=0;i<nEndPos.length-1;i++) q2<J`G(tZ  
{ 2.lnT{  
nEndPos = nStartPos[i+1]; F9+d7 Y$  
}
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nEndPos[nEndPos.length-1] = nFileLength; X)&Z{ V>  
} wRiP5U,  
} Z?Q2ed*j  
Ph%s.YAZ~  
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//启动子线程 `Ys })Pl  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~fU
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for(int i=0;i<nStartPos.length;i++) mpF_+Mn  
{ *nC,=2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h?1pGz)[C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lb6s3b  
nStartPos,nEndPos,i); bn(Scl#
@K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nRE}F5k  
fileSplitterFetch.start(); 0$_imjZ  
} `i:0dVs  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7lj-Z~1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7S7!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y}#^n7*w~  
nEndPos = " + nFileLength); f:Ja  
// fileSplitterFetch[nPos.length-1].start(); 'q^Gg;c>+  
D8#q.OR]  
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//等待子线程结束 y^Jv?`jw  
//int count = 0; jbGH3 L  
//是否结束while循环 RQ'c~D)X  
boolean breakWhile = false; dB,#`tc=,  
w:LCm `d  
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while(!bStop) (hV"z;rI  
{ %i "  
write_nPos(); *Fc&DQT(  
Utility.sleep(500);
;' W5|.ZN  
breakWhile = true; !?>)[@2 k6  
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for(int i=0;i<nStartPos.length;i++) >V$#Um?AXj  
{ ^MW%&&,BL  
if(!fileSplitterFetch.bDownOver) )/AvWDKvO  
{ Iq=B]oE  
breakWhile = false; 8WGM%n#q  
break; :V2Q n-N  
} prs<ZxbQb  
} Xda<TX@-  
if(breakWhile) iHn]yv3 #  
break; wEbs E<</  
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//count++; 7EO&:b]  
//if(count>4) DnFl*T>  
// siteStop(); q{ 1U  
} }\{1`$*~  
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System.err.println("文件下载结束！"); 7x]nY.\
 
} {4 d$]o0V  
catch(Exception e){e.printStackTrace ();} %Eh%mMb^  
} u_"h/)C'H  
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//获得文件长度 c]r|I%D  
public long getFileSize() NKKOA  
{ ?t42=nvf  
int nFileLength = -1; UhTr<(@  
try{ kf!/9  
URL url = new URL(siteInfoBean.getSSiteURL()); ?KXQ)Y/su  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x=#5\t9  
httpConnection.setRequestProperty("User-Agent","NetFox"); .8!0biS  
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int responseCode=httpConnection.getResponseCode(); |P7f^0idk  
if(responseCode>=400) o)=VPUe  
{ EI.Pk>ZIm  
processErrorCode(responseCode); =*}Mymhk(  
return -2; //-2 represent access is error +|<&#b0Xd  
} aF
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6<$|;w-OV  
String sHeader; xm0#4GFUS  
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for(int i=1;;i++) B/hHkOoo  
{ \87J~K'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); z]|[VM?4L  
//Utility.log(in.readLine()); 9prsL#Fn  
sHeader=httpConnection.getHeaderFieldKey(i); y(  
if(sHeader!=null) 7NC8<o;  
{ da'E"HN@G~  
if(sHeader.equals("Content-Length")) X/Rx]}[   
{ 5)5bt q)[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M9g\/]Io;  
break; "4hpU]4j  
} cEjdImAzU  
} $#FlnM<=  
else 97wy;'J[u  
break; ~+ wamX3  
} g Pj0H&,.  
} %=8(B.I!  
catch(IOException e){e.printStackTrace ();} 2\\3<  
catch(Exception e){e.printStackTrace ();} @h$0S+?:  

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Utility.log(nFileLength); F'$S!K58  

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return nFileLength; EJ ~kZ3  
} Q9xx/tUW  
)$h9Y   
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//保存下载信息（文件指针位置） 3t{leuO'  
private void write_nPos() lO:{tV  
{
&N_c-@2O  
try{ 7QiCZcb\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); xyjVdD\  
output.writeInt(nStartPos.length); '
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for(int i=0;i<nStartPos.length;i++) kz;_f  
{ A=C3e4.C  
// output.writeLong(nPos); wy- C~b'Qd  
output.writeLong(fileSplitterFetch.nStartPos); qZsddll  
output.writeLong(fileSplitterFetch.nEndPos); ~)a;59<$  
} G0 /vn9&  
output.close(); ~P#zhHw  
} <N=p:e,aN,  
catch(IOException e){e.printStackTrace ();} `s>=Sn&UP  
catch(Exception e){e.printStackTrace ();} @IY?DO  
} xhkWKB/7  
%"[dGB$S  
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//读取保存的下载信息（文件指针位置） Te@6N\g  
private void read_nPos() SslY]d]  
{ 5Vo}G %g  
try{ ;;'a--'"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ji:iKkI  
int nCount = input.readInt(); 4<Sa,~4  
nStartPos = new long[nCount]; 7 Y>`-\  
nEndPos = new long[nCount]; MR_bq_)  
for(int i=0;i<nStartPos.length;i++) RjGB#AK  
{ :-\ yy  
nStartPos = input.readLong(); %^5@z1d,  
nEndPos = input.readLong(); >`<2}Me6  
} {ogZT7w}  
input.close(); Dp*$GQ  
} 1:x
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catch(IOException e){e.printStackTrace ();} %FyygTb;S  
catch(Exception e){e.printStackTrace ();} !ObE{2Enf  
} zYG,x*IH  
"8muMa8Q%  
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private void processErrorCode(int nErrorCode) ^'[@M'`~L  
{ h [IYA1/y  
System.err.println("Error Code : " + nErrorCode); }S vw,c  
} .y7)XLC  
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//停止文件下载 q|u8CX  
public void siteStop() \_*MJ)h)X  
{ -[pCP_`)u  
bStop = true; HD:%
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for(int i=0;i<nStartPos.length;i++) |N$?_<H  
fileSplitterFetch.splitterStop(); <P^hYj-swh  
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} 5{FM#@  
} [Yy\>  
//负责部分文件的抓取
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**FileSplitterFetch.java 9vp%6[  
*/ PyMVTP4  
package NetFox; `B'4"=(  
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import java.io.*; O*rmD<L$  
import java.net.*; v<%kd[N  
^'7C0ps+A  
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public class FileSplitterFetch extends Thread { r9] rN  
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String sURL; //File URL MV<!<Qmj  
long nStartPos; //File Snippet Start Position !2Y!jz  
long nEndPos; //File Snippet End Position ?]W~ qgA  
int nThreadID; //Thread's ID Xn/ n|[  
boolean bDownOver = false; //Downing is over `.>k)=F&  
boolean bStop = false; //Stop identical L%WME8PB  
FileAccessI fileAccessI = null; //File Access interface afY_9g!\  
8Z dUPW\e  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %'"HGZn b  
{ <rB3[IJo  
this.sURL = sURL; 7!r#(>I6?1  
this.nStartPos = nStart; ;v1NL@w*  
this.nEndPos = nEnd; {Vxc6,=  
nThreadID = id; $U>/i@D  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 v]:+`dV  
} ;+i'0$;*w  
l`b1%0y  
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public void run() 7$ =Y\P  
{ ~{4n}*  
while(nStartPos < nEndPos && !bStop) PUP"ky^q"  
{ e"fN~`NhY  
"!%wh6`>Md  
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try{ I/O
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URL url = new URL(sURL); SE^j=1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j,C,5l=  
httpConnection.setRequestProperty("User-Agent","NetFox"); j0iAU1~_VX  
String sProperty = "bytes="+nStartPos+"-"; |DE%SVZB  
httpConnection.setRequestProperty("RANGE",sProperty); !/j,hO4Z4  
Utility.log(sProperty); w; 4jx(  
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%kh#{*q$  
InputStream input = httpConnection.getInputStream(); Q(510)  
//logResponseHead(httpConnection); iuC7Y|  
1~2R^#rm  
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byte[] b = new byte[1024]; }bf=Ntk  
int nRead; 22`oFXb'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dGW{l]N  
{ SyK9Is{8  
nStartPos += fileAccessI.write(b,0,nRead); %9C`  
//if(nThreadID == 1) 9Uha2o  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N]14  
} ZfPd0 p  
jt{9e:2%  
oW1"%i%  
Utility.log("Thread " + nThreadID + " is over!"); ~x|aoozL  
bDownOver = true; ~:>AR` 9G  
//nPos = fileAccessI.write (b,0,nRead); #:J:YMv  
} *@_u4T7|{  
catch(Exception e){e.printStackTrace ();} keLR1qf  
}
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} e74zR6  
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//打印回应的头信息 U4>O\sU  
public void logResponseHead(HttpURLConnection con) 5@P%iBA4(3  
{ 'K@-Z]  
for(int i=1;;i++) RU2c*q$^X  
{ "S5S|dBc  
String header=con.getHeaderFieldKey(i); KRYcCn  
if(header!=null)  fb\DiKsW  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ugYw<  
Utility.log(header+" : "+con.getHeaderField(header)); "8N"Udu  
else TQP+>nS,  
break; XZS5B~E '  
} 8|O=/m^]  
} N&T:Lt_N  
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public void splitterStop() s%~L4Wmcq  
{ RMoJz6^>  
bStop = true; y 'OlQ2U  
} "EoDQT"0  
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} 2-++i:, g  
t|}O.u-&;~  
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/* 5m4DS:&  
**FileAccess.java !(Krf  
*//文件访问(定位，写) 57~Uqt  
package NetFox; nV}8M  
import java.io.*; (}Sr08m  
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public class FileAccessI implements Serializable{ !z"N
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?"6Ov ]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ueDvMP  
RandomAccessFile oSavedFile; St@l]u9  
long nPos; e}A&
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public FileAccessI() throws IOException GnFs63  
{ B'-I{~'/  
this("",0); YOyp|%!  
} "PMQyzl  
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public FileAccessI(String sName,long nPos) throws IOException z8HsYf(!  
{ 9R p2W  
oSavedFile = new RandomAccessFile(sName,"rw"); Z%}4bJ  
this.nPos = nPos; B0d%c&N${  
oSavedFile.seek(nPos); G@gh#[b  
} jd 1jG2=f  
%j7:tf=  
k=[pm5ZvT~  
public synchronized int write(byte[] b,int nStart,int nLen) fc@'9-pt  
{ $X\va
?(  
int n = -1; ["y6b*;x  
try{ r}_lxr  
oSavedFile.write(b,nStart,nLen); L@RIZu>ZW+  
n = nLen; qI%&ay"/  
} s)zJT  
catch(IOException e) 3JO]f5  
{ OfTfNhpK  
e.printStackTrace (); mN*?%t  
} PU1,DU  
?]#OM_,8  
mdW~~-@H  
return n; xzsdG?P  
} h7]EB!D\A  
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} Ipe n  
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/* _V2xA88
 
**SiteInfoBean.java Zd!U')5/  
*/ edipA P~!  
package NetFox; (YPi&w~S  
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public class SiteInfoBean { yVX8e I  
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private String sSiteURL; //Site's URL -]srp;=i  
private String sFilePath; //Saved File's Path M
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private String sFileName; //Saved File's Name PLX>-7@  
private int nSplitter; //Count of Splited Downloading File oDn|2Sdqd  
M f~}/h  
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public SiteInfoBean() o`n$b(VZ  
{//nSplitter的缺省值为5 j8Cho5C  
//default value of nSplitter is 5 ,ho3  
this("","","",5); 5T@aCC@$h  
} l(;Kij  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) pav'1d%  
{ 9QQyl\  
sSiteURL= sURL; *=AqM14 @  
sFilePath = sPath; =WIJ>#Go<  
sFileName = sName; #bX9Tu0  
this.nSplitter = nSpiltter; A A^{B  
bi[IqU!9  
/FD5G7ES  
} t.p~\6
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public String getSSiteURL() V#REjsf,t-  
{ z2_6??tS/c  
return sSiteURL; #>lG7Ns|4  
} Lk\P7w{  
1u3,'8F  
El\%E"Tk%  
public void setSSiteURL(String value) 0:w"M<80  
{ SZaS;hhhHu  
sSiteURL = value; I9h ?;(  
} #Cpd9|  
hj'(*ND7z  
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public String getSFilePath() }>)[<;M>%  
{ "&/-N[is  
return sFilePath; !?c|XdjZ  
} 4=<tWa|@9  
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public void setSFilePath(String value) !*RqCS,  
{ Zm6{n'  
sFilePath = value; _ODbY;M  
} X}+>!%W!}  
3EJt%}V$k  
lOtDqb&  
public String getSFileName() 'yMF~r3J  
{ :POj6j/  
return sFileName; "[y-
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} uj :%#u  
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public void setSFileName(String value) |yx6X{$k  
{ J0@X<Lt U  
sFileName = value; oYukLr  
} rqY`8Ry2M  
I:mr}mv=i  
\[y`'OD~  
public int getNSplitter() y3fGWa*7e  
{ y&V@^"`  
return nSplitter; rx]  @A  
} tCdqh- 
 
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public void setNSplitter(int nCount) >r!|sC  
{ [PDNwh0g5  
nSplitter = nCount; .>WxDQIo  
} #w' k
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} >
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7eAX*Kgt<_  
/* -4 SY=NC_  
**Utility.java d8c=L8~jt  
*/ R=QZgpR  
package NetFox; ?vbvBu{a  
oC0qG[yp9S  
xCc[#0R{  
public class Utility { AJF#Aw `o  
,^\2P$rT  
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public Utility() gcl5jB5)>  
{ zd >t-?g  
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y.< m#Zzt  
} M 0U0;QJ  
G$F<$  
//线程睡眠 Wa{`VS  
public static void sleep(int nSecond) @eKec1<  
{ ddJe=PUb  
try{ X:nN0p #  
Thread.sleep(nSecond); "W955?4m  
} W*),y:  
catch(Exception e) woGAf)vV#  
{ lww!-(<ww  
e.printStackTrace (); N
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} H[U!%Z  
} #."-#"0  
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//日志 Nh_Mz;ITuu  
public static void log(String sMsg) B#Vz#y  
{ r{L> F]Tw  
System.err.println(sMsg); >I-RGW'A  
} *Doa*wQ  
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CYY=R'1:G{  
public static void log(int sMsg) $QLcH;+7t  
{ 8 Hg+H=?  
System.err.println(sMsg); 2fn&#kw/  
} }HFN3cq;C  
} P2#XKG  
i:Y^{\Z?V  
M_/7D|xl/T  
/* QI'Oz{vE  
**TestMethod.java "K6&dk jY  
*/ :VRNs  
package NetFox; 4.[^\N  
,St#Vla  
dxMOn  
public class TestMethod { jCOIuw  
)rn*iJ.e8  
OEA&~4&{7  
public TestMethod() 'vbsvT  
{ ///xx/weblogic60b2_win.exe }ppN k:B  
try{ X86O lP)eX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Jh,]r?Bd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); sBvzAVBL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;-~B)M_S`  
fileFetch.start(); tE<H|_{L  
} cQy2"vtU  
catch(Exception e){e.printStackTrace ();} zPn+V7F  
"O3tq=Q  
m Bu  
} nP$Ky1y G  
v_+{'F  
@E7DyU|  
public static void main(String[] args) Z'`<5A%;  
{ M?Y;a5{  
new TestMethod(); ,8U&?8l  
} snE8 K}4  
} [=6]+V83M  
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