http断点续传简单实现（java)

/* \:UIc*S  
**SiteFileFetch.java ;4pYK@9w_  
*/ q0zr E5  
package NetFox; sjV!5Z  
import java.io.*; \vO,Ee~#W  
import java.net.*; uu>Pkfo  
@8I4[TE  
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public class SiteFileFetch extends Thread { (R("H/6xs  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )z28=
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long[] nStartPos; //开始位置 Ptdpj)oi&Q  
long[] nEndPos; //结束位置 L}pt)w*V1j  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 W@I|Q -  
long nFileLength; //文件长度 Zo~  
boolean bFirst = true; //是否第一次取文件 @P?~KW6<|  
boolean bStop = false; //停止标志 XY3v_5~/1F  
File tmpFile; //文件下载的临时信息 Z
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DataOutputStream output; //输出到文件的输出流 fd.^h*'mU  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,]d/Q<  
public SiteFileFetch(SiteInfoBean bean) throws IOException @W"KVPd  
{ z+n,uHs  
siteInfoBean = bean; ybKWOp:O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); lE(a%'36  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /x p|  
if(tmpFile.exists ()) }xh$T'M8  
{ :BV6y|J9O^  
bFirst = false; m3/O.DY%0  
read_nPos(); [UWdW  
} M]2]\km  
else !*B'?|a<\  
{  x5-}h*  
nStartPos = new long[bean.getNSplitter()]; @X;!92i  
nEndPos = new long[bean.getNSplitter()]; z?*w8kU&>  
} >]vlkA(  
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} 2KYw}j|5  
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public void run() ;"~ fZ2$U  
{ x#xFh0CA  
//获得文件长度 :Ra,Eu  
//分割文件 =*c7i]@}  
//实例FileSplitterFetch .7avpOfz  
//启动FileSplitterFetch线程 A#J`;5!Sc  
//等待子线程返回 lHPd"3HDK  
try{ SPY|K  
if(bFirst) ORJIo
  
{ mQ|v26R  
nFileLength = getFileSize(); g'n7T|h ~  
if(nFileLength == -1) 9\mLW"  
{ Vg>dI&O  
System.err.println("File Length is not known!"); ]rH\`0  
} MS 81sN\d  
else if(nFileLength == -2) 9Hb6nm  
{ tne ST.  
System.err.println("File is not access!"); !C3MFm{B  
} |es?;s'  
else #(N+(():  
{ O @j} K4  
for(int i=0;i<nStartPos.length;i++) ':3pq2{  
{ R5-

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nStartPos = (long)(i*(nFileLength/nStartPos.length)); P"IPcT%Ob%  
} iW%I|

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for(int i=0;i<nEndPos.length-1;i++) H2jgO?l;!  
{ AicBSqUke  
nEndPos = nStartPos[i+1]; 3yU.& k  
} bU2Z[sn.  
nEndPos[nEndPos.length-1] = nFileLength; ][+#;avU  
} IID-k  
} v,-HU&/*B  
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d\|?-hY`[  
//启动子线程 $!-c-0ub  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; R6kD=JY/!  
for(int i=0;i<nStartPos.length;i++) 4gz H8sF  
{ %\dz m-d(C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <66X Xh.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7e|s wJ>4  
nStartPos,nEndPos,i); O7-mT8o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q1"$<# t  
fileSplitterFetch.start(); F@'Jbd`   
} 1Z+8r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W14 J],{L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !Sh&3uy_qN  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p6#g;$V$  
nEndPos = " + nFileLength); i1NY9br  
// fileSplitterFetch[nPos.length-1].start(); t\~P:"  
|y!=J$$_H  
(a.z9nqGA  
//等待子线程结束 i@)i$i4
  
//int count = 0; 75f"'nJ)  
//是否结束while循环 Q  Nh|Wz  
boolean breakWhile = false; -pf}  
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while(!bStop) bnq;)>&  
{ 2Mc3|T4)U  
write_nPos(); ODNM+#}`  
Utility.sleep(500); nYR#  
breakWhile = true; K1"*.\?F  
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for(int i=0;i<nStartPos.length;i++) 4:$4u@   
{ Ai=se2  
if(!fileSplitterFetch.bDownOver) N kb|Fd/s  
{ G'Q-An%z  
breakWhile = false; iNtaDX|%/  
break; JQ8fdP A  
} O`x;,6Vr  
} 1PVtxL?1P  
if(breakWhile) Z_};|B}  
break; v7BA[jQr  
D[aCsaR  
dx5#\"KX=,  
//count++; A&.WH?p  
//if(count>4) Vd,jlt.t  
// siteStop(); (
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} J%v=yBC2  
V:In>u$QJ!  
); !eow  
System.err.println("文件下载结束！"); W=^#v  
} n$xc];j  
catch(Exception e){e.printStackTrace ();} [842&5Pd?  
} WejYy|  
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//获得文件长度 Q('r<v96  
public long getFileSize() `5cKA;j>b  
{ &S{RGXj_  
int nFileLength = -1; >kj`7GA  
try{ qON|4+
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URL url = new URL(siteInfoBean.getSSiteURL()); @Owb?(6?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cs,N <|  
httpConnection.setRequestProperty("User-Agent","NetFox"); +%zAQeb  
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int responseCode=httpConnection.getResponseCode(); j"
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if(responseCode>=400) lGPUIoUo  
{ Bn=by{i  
processErrorCode(responseCode); .0S~872  
return -2; //-2 represent access is error Uol|9F  
} 1n >X[! 8x  
AF;)#T<  
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String sHeader; 3m]4=  
9_L[w\P|4  
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for(int i=1;;i++) ?{P"O!I{  
{ @TLS<~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); iEVb"w059  
//Utility.log(in.readLine()); +X#vVD3"  
sHeader=httpConnection.getHeaderFieldKey(i); w k(VR  
if(sHeader!=null) q MfT>rH  
{ J`peX0Stl  
if(sHeader.equals("Content-Length")) 3 R=,1<  
{ ypbe!Y<i]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m!|kW{B#A  
break; nW PF6V>  
} /7aBDc-v  
} =e/9&993  
else s>B5l2Q4  
break; j`JMeCG=Ee  
} )
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} iZ#!O*>  
catch(IOException e){e.printStackTrace ();} F3N?Nk/  
catch(Exception e){e.printStackTrace ();} "Q}#^h]F  
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Utility.log(nFileLength); '-r).Xk  

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return nFileLength; d?s<2RkPT  
} ~ZmN44?R  
;X8yFq  
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//保存下载信息（文件指针位置） bx#>BK!  
private void write_nPos() F|d\k Q
 
{ o1-m1<ft  
try{ 3B1XZm  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |jQ:~2U|  
output.writeInt(nStartPos.length); =}lh_  
for(int i=0;i<nStartPos.length;i++) 8ZM?)#`@{  
{ lW+\j3?Z$  
// output.writeLong(nPos); :}Xll#.,m  
output.writeLong(fileSplitterFetch.nStartPos); O!mvJD  
output.writeLong(fileSplitterFetch.nEndPos); 5QW=&zI`=  
} 8>trS=;n  
output.close(); (n*^4@"2
 
} > A Khf  
catch(IOException e){e.printStackTrace ();} )_+rU|We  
catch(Exception e){e.printStackTrace ();} <>dT64R|  
} Y'c>:;JEe  
 |XT)QK1  
M`. tf_x  
//读取保存的下载信息（文件指针位置） !S^AgZ~  
private void read_nPos() G<At_YS  
{ 0C =3dnp6  
try{ H35S#+KX  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  J}htu  
int nCount = input.readInt(); j
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nStartPos = new long[nCount]; UR%/MV  
nEndPos = new long[nCount]; ?+_Gs;DGVE  
for(int i=0;i<nStartPos.length;i++) FK:;e lZ  
{ dU6ou'pf  
nStartPos = input.readLong(); xAqb\|$^  
nEndPos = input.readLong(); YNLV9.P6  
} un)4eo!7  
input.close(); NE"@Bk cm  
} cQ/5
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catch(IOException e){e.printStackTrace ();} R{WE\T'  
catch(Exception e){e.printStackTrace ();} 9*2[B"5  
} C\3y
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private void processErrorCode(int nErrorCode) $&y%=-]|  
{ yyoqX"v[  
System.err.println("Error Code : " + nErrorCode); $LKIT0  
} (*Z)(O*z  
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{\
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//停止文件下载 m`v2: S}  
public void siteStop() JI?rL  
{ I, -hf=-  
bStop = true; ]Uw<$!$-]s  
for(int i=0;i<nStartPos.length;i++) V 
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fileSplitterFetch.splitterStop(); M
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NV)!7~r}:  
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} )hd@S9Z
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} _p#CwExuy  
//负责部分文件的抓取 CKtB-a  
**FileSplitterFetch.java &+a9+y  
*/ Fw/6?:C}O6  
package NetFox; C+?Hm1  
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~Fe${2
 
import java.io.*; )i~cr2Hk  
import java.net.*; +1Vjw'P  
CAWA3fcQp  
*meZ8DV2DH  
public class FileSplitterFetch extends Thread { c;%_EN%  
`sUZuWL_  
wHsYF`  
String sURL; //File URL 3Vsc 9B"w  
long nStartPos; //File Snippet Start Position dA-2%uJ  
long nEndPos; //File Snippet End Position nIAx2dh?  
int nThreadID; //Thread's ID iDN;m`a  
boolean bDownOver = false; //Downing is over m$`RcwO  
boolean bStop = false; //Stop identical 6Se?sHC>  
FileAccessI fileAccessI = null; //File Access interface V_>\9m  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Scp7X7{N  
{ M^MdRu  
this.sURL = sURL; l*ayd>`~x  
this.nStartPos = nStart; ;6gDV`Twy  
this.nEndPos = nEnd; jYx38_5e  
nThreadID = id; 4,..kSA3iw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h"Xg;(K  
} g+DzscIT  
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public void run() QBtnx[  
{ #%`|~%`{:  
while(nStartPos < nEndPos && !bStop) 9)0D~oUi  
{ FjK3 .>'  
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try{ D5$wTI  
URL url = new URL(sURL); Q<z_/j9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5 elw~u  
httpConnection.setRequestProperty("User-Agent","NetFox"); E_Im^a  
String sProperty = "bytes="+nStartPos+"-"; 6^%UU o%  
httpConnection.setRequestProperty("RANGE",sProperty); LL]zT H0  
Utility.log(sProperty); @WJgWJm  
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InputStream input = httpConnection.getInputStream(); 7bqBk,`9  
//logResponseHead(httpConnection); ykv94i?Q  
;E@G`=0St  
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byte[] b = new byte[1024]; |B.0TdF  
int nRead; &?VQ,+[<
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tDSJpW'd  
{ kV?y0J.  
nStartPos += fileAccessI.write(b,0,nRead); 9w"h  
//if(nThreadID == 1) M>DaQ`b  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kz{/(t  
} 6726ac{xz  
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Utility.log("Thread " + nThreadID + " is over!"); 3l)hyVf&  
bDownOver = true; aT_&x@x  
//nPos = fileAccessI.write (b,0,nRead); 8S>&WR%jH]  
} umD!
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catch(Exception e){e.printStackTrace ();} AP[|Ta  
} 6^uq?  
} T^:UBjK6t{  
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NZ;{t\  
//打印回应的头信息 fYp'&Btb]x  
public void logResponseHead(HttpURLConnection con) D|@/yDQ  
{ JmPHAUd  
for(int i=1;;i++) OTMJ6)n7  
{ 1v,Us5s<"6  
String header=con.getHeaderFieldKey(i); aD=a,  
if(header!=null) S M!Txe#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); f-}[_Y%;  
Utility.log(header+" : "+con.getHeaderField(header)); N*%@  
else !xP8#|1  
break; 5Ycco,x  
} a-l;vDs  
} $"0MU  
HOw-]JSP2  
m0LTx\w!  
public void splitterStop() 8d?g]DEN)6  
{ "5;;)\o~  
bStop = true; ?z}=B  
} hZh9uI7.  
^
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} x\F,SEj  
-`<kCW"  
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/* g) p,5BADm  
**FileAccess.java lrnyk(M}Q.  
*//文件访问(定位，写) CK:y?  
package NetFox; KC(xb5x Y  
import java.io.*; NLS
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CLeG<Hi ~  
public class FileAccessI implements Serializable{ mocI&=EF2X  
D@.tkzU@E  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _u{c4U0,  
RandomAccessFile oSavedFile; \cC%!4  
long nPos; Jj,U RD&0R  
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public FileAccessI() throws IOException gN24M3{C  
{ D|rFu  
this("",0); dY@WI[yog  
} u
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public FileAccessI(String sName,long nPos) throws IOException 43={Xy   
{ rA2g&  
oSavedFile = new RandomAccessFile(sName,"rw"); Y|8:
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this.nPos = nPos; BhM'@g*  
oSavedFile.seek(nPos); T%6&PrQ7  
} rFaF Bd  
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public synchronized int write(byte[] b,int nStart,int nLen) zunV<2~(2}  
{ B*4}GPQ  
int n = -1; Ggl~nxz  
try{ ,Y|^^?'j Q  
oSavedFile.write(b,nStart,nLen); bx]N>k J  
n = nLen; IX*
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} XK|R8rhg8`  
catch(IOException e) %CS@g.
H=_  
{ f 1w~!O9  
e.printStackTrace ();  emK$`9  
} Kl2lbe7  
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Cl^\OZN\=  
return n; 0{dz5gUde  
} Lb;zBmwB  
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} 3l3+A+n  
%=?cZfFqO  
e=4+$d  
/* oI}kH=<,  
**SiteInfoBean.java DA2}{  
*/ -8r  
package NetFox; ~><^'j[  
T:/,2.l  
3 n'V\Hvz  
public class SiteInfoBean { A,%C,*)Cg  
Hir Fl  
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enum  
private String sSiteURL; //Site's URL EI
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private String sFilePath; //Saved File's Path F>]m3(  
private String sFileName; //Saved File's Name 1Ab>4UhD  
private int nSplitter; //Count of Splited Downloading File Q$:![}[(  
p/U+0f  
bYi`R)  
public SiteInfoBean() 2RN)<\P  
{//nSplitter的缺省值为5 oS7(s  
//default value of nSplitter is 5
\3'9Uz,OC  
this("","","",5); aX~%5mF  
} AX= 1b,s  
abJ" [  
AJSx%?h:6  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qTAc[Ko  
{ br0++}vwL  
sSiteURL= sURL; ?Y:8eD"*  
sFilePath = sPath; zN{K5<7o  
sFileName = sName; TQ`Rk;0R  
this.nSplitter = nSpiltter; LJOr!rWi  
UTf9S>HS  
#]#sGmW/L  
} "TUe%o  
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:$_6SQ<?  
public String getSSiteURL() H}H7lO  
{ Nnk@h  
return sSiteURL; mcn 2Wt  
}  ~BDu$  
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`5~ +,/Ys  
public void setSSiteURL(String value) $Bj;D=d@V  
{ ^2$ lJ
  
sSiteURL = value;  qNm$Fx  
} -jn WZ5.  
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'0\@McU]  
public String getSFilePath() t=u Qb=  
{ ?gPKcjgoH!  
return sFilePath; 5Q 'i2*j  
} >[Ye  
&BtK($  
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public void setSFilePath(String value) 549jWG  
{ #f
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sFilePath = value; rQEyD  
} 5w\fSY  
52b*[tZ  
K{ \;2M  
public String getSFileName() `E!N9qI?t$  
{ "Vr[4&`  
return sFileName; ]D@0|  
} l#lF +Q;  
9_QP!,  
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public void setSFileName(String value) 2MATpV#BT  
{ 0vVV%,v  
sFileName = value; {0;3W7  
} P ~#>H{  

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public int getNSplitter() Qc[3Fq,f  
{
8E8N6  
return nSplitter; kN%MP6?J  
} &AlJ "N|  
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public void setNSplitter(int nCount) eeHP&1= 7  
{ 6<'rG''  
nSplitter = nCount; "Tm[t?FMbe  
} ,^gyH \  
} R|f~>JUF  
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M\Gdn92pd  
/* k{VE1@  
**Utility.java ?6nF~9Z'  
*/ kPQtQh]y%  
package NetFox; }U SC1J  
aA'|Rg,  
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public class Utility { FSRm|  
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public Utility() >(y<0   
{ 9}c8Xt^&  
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} pGSai&  
[w\9as/ E  
//线程睡眠 mKT>,M  
public static void sleep(int nSecond) p-%|P]&  
{ }gkM^*$:%  
try{ 11|Rdd+}  
Thread.sleep(nSecond); h(qQsxIOhS  
} pDQ}*  
catch(Exception e) lc_E!"1  
{ EwS!]h?  
e.printStackTrace (); lpRR&
  
} f30Pi1/h=c  
} /XudV2P-CA  
y7S4d~&  
//日志 /m(=`aRt  
public static void log(String sMsg) rC
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{ ^m/14MN|  
System.err.println(sMsg); NxVw!TsR  
} a=XW[TY1  
hk/! 'd  
Sa"9^_.2#  
public static void log(int sMsg) Dfd-^N!  
{ SlSM+F  
System.err.println(sMsg); k|BHnj  
} vA)O{W\o  
} c8Q]!p+Yp  
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*cTO7$\[  
/* 84i_k  
**TestMethod.java #wc \T  
*/ ^FZ^6*
 
package NetFox; w'X]M#Q><  
oo=#XZkk  
l{VSb92f  
public class TestMethod { 'xv8Gwf"  
=&!HwOnp  
tA$)cg+.  
public TestMethod() <`!PCuR  
{ ///xx/weblogic60b2_win.exe Qm8)4?FZ  
try{ `VQb-V  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |0{u->+ )  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jKZt~I  
SiteFileFetch fileFetch = new SiteFileFetch(bean); YF:2>w<  
fileFetch.start(); h;V,n  
} w[_x(Ojq;  
catch(Exception e){e.printStackTrace ();} DFO7uw1  
]APvp.Tw:  
dr{y0`CCN  
} -[OXSaf6  
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public static void main(String[] args) |wox1Wt|E  
{ 8h<ehNX ^I  
new TestMethod(); $6F)R|  
} xsjO)))f  
} pPVRsXy  
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