http断点续传简单实现（java)

/* @
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**SiteFileFetch.java J9t?]9.,:  
*/ YhK/pt43C  
package NetFox; g<tTZD\g  
import java.io.*; $P9$ ,w4  
import java.net.*; d3J_IW+8R$  
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public class SiteFileFetch extends Thread { ]8nm9qmF<  
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SiteInfoBean siteInfoBean = null; //文件信息Bean $ttr_4=  
long[] nStartPos; //开始位置 Dk6\p~q  
long[] nEndPos; //结束位置 h#;K9#x6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 
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long nFileLength; //文件长度 _ShJ3\,K  
boolean bFirst = true; //是否第一次取文件 3t6'5{  
boolean bStop = false; //停止标志 QHz76i!=>  
File tmpFile; //文件下载的临时信息 O*CX@Ne  
DataOutputStream output; //输出到文件的输出流 {!bJ.O l  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） MpvA--  
public SiteFileFetch(SiteInfoBean bean) throws IOException U4pvQE.m<  
{ Ybg`Z  
siteInfoBean = bean; +-137!x\q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); H pfI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `g1~ya(MC  
if(tmpFile.exists ()) 3<E$m*  
{ xF31%b`z:  
bFirst = false; 7B :aJfxM  
read_nPos(); 2b` M(QL  
} DQQjx>CK  
else y_r6T XnGL  
{ BJrNbo;T  
nStartPos = new long[bean.getNSplitter()]; f|E'eFrFk  
nEndPos = new long[bean.getNSplitter()]; `t2! M\)  
} {<BK@U  
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} 'FXZ`+r|  
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public void run() %c{)'X  
{ :UciFIa  
//获得文件长度 ((q(Q9(F  
//分割文件 e:R[  
//实例FileSplitterFetch ,"ZlY}!Gn  
//启动FileSplitterFetch线程 DR=1';63  
//等待子线程返回 -l
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try{ =0Sa  
if(bFirst) n\Nl2u& m  
{ \}W.RQ^3  
nFileLength = getFileSize(); G8'3.;"W5  
if(nFileLength == -1) $Yc9><i  
{ SO"P3X  
System.err.println("File Length is not known!"); 58,mu#yq6  
} OwUbm0)h^V  
else if(nFileLength == -2) mD3#$E!A1  
{ /+YWp>6LU  
System.err.println("File is not access!"); PN=yf@<V3F  
} :8 :>CHa  
else /.bwwj_;  
{
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for(int i=0;i<nStartPos.length;i++) p10->BBg  
{ (z{xd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); GYO"1PM  
} 2t<CAKBB  
for(int i=0;i<nEndPos.length-1;i++) >{Q2S  
{ @}:(t{>;e7  
nEndPos = nStartPos[i+1]; Jjv&@a}  
} k$c!J'qL&  
nEndPos[nEndPos.length-1] = nFileLength; we3t,?`rk7  
} v3Kqs:"\  
} yFjSvm6  
t|%ul6{gz  
=UN:IzT  
//启动子线程 PR0]:t)E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]h
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for(int i=0;i<nStartPos.length;i++) c9V'Zd#  
{ XT)@)c7j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .E(Ucnz/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I6+5mv\  
nStartPos,nEndPos,i); u}$3.]-.?T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t"Rn#V\c."  
fileSplitterFetch.start(); %"D-1&%zY  
} -VL3em|0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L-yC'C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); u-,=C/iU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", TD<.:ul]  
nEndPos = " + nFileLength); qmhHHFjQ  
// fileSplitterFetch[nPos.length-1].start(); WD<M U ]  
8I%1 `V  
}/=_  
//等待子线程结束 8l6R.l  
//int count = 0; *=rl<?tX  
//是否结束while循环 c;VW>&,B  
boolean breakWhile = false; 74_ji!  
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while(!bStop) ]*).3<Lw  
{ ~~&M&Fe  
write_nPos(); /}Max@.`  
Utility.sleep(500); 5Jd,]~KAP  
breakWhile = true; EG,RlmcPp  
wNn6".S   
 i -+B{H  
for(int i=0;i<nStartPos.length;i++) n,`&f~tap  
{ [dL#0~CL$  
if(!fileSplitterFetch.bDownOver) U.&=b<f(0r  
{ Zi^&x6y^  
breakWhile = false; >
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break; ~%cbp&s*/q  
} _15r!RZ:1  
} w1[F]|  
if(breakWhile) P:=3;d{v  
break; *g7dB2{  
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|VIBSty2d  
//count++; R
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//if(count>4) 2|+**BxHD  
// siteStop(); E1=]m  
} .-{B  
I_4'9  
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System.err.println("文件下载结束！"); ^8DC W`V  
} ^J?I-LG  
catch(Exception e){e.printStackTrace ();} d+$a5 [^9  
} RV-
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//获得文件长度 !ce:S!P  
public long getFileSize() ygh*oVHO  
{ 72.ZE%Ue  
int nFileLength = -1; smJ%^'x
 
try{ lj(}{O  
URL url = new URL(siteInfoBean.getSSiteURL()); dx?4)lb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !ce5pA  
httpConnection.setRequestProperty("User-Agent","NetFox"); >J+hu;I5  
|,|b~>  
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int responseCode=httpConnection.getResponseCode(); QOMh"wC3  
if(responseCode>=400) __OD^?qa  
{ #)z_TM07P  
processErrorCode(responseCode); 46Vx)xX  
return -2; //-2 represent access is error &Nl:  
} VU9w2/cM  
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String sHeader; adRvAq]mA  
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for(int i=1;;i++) A70x+mjy^T  
{ N;Wm{~Zhb  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0x*L
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//Utility.log(in.readLine()); #**vIwX-Q  
sHeader=httpConnection.getHeaderFieldKey(i); ]X%T^3%G  
if(sHeader!=null) kO>F, M  
{ LR|LP)I  
if(sHeader.equals("Content-Length")) v47Y7s:uQ  
{ `KgIr,Q)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v2][gn+58  
break; !lpKZG  
} bxLeQWr6  
} /{QR:8}-Q  
else vau0Jn%=ck  
break; uczOSd  
} D',[M)  
} 8K$q6V%#  
catch(IOException e){e.printStackTrace ();} u2}zRC=  
catch(Exception e){e.printStackTrace ();} 8&+m5xS  
m_ >+$uL  
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Utility.log(nFileLength); JO{Rth  
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return nFileLength; IWc?E  
} x=]PE}<E  
&Cv0oi&B  
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//保存下载信息（文件指针位置） *c<0cHv*  
private void write_nPos() e!BablG[  
{ ]w*w@:Zk  
try{ 6'E3Q=}d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); b8o}bm{s  
output.writeInt(nStartPos.length); C5k\RS9  
for(int i=0;i<nStartPos.length;i++) E3%:7MB  
{ =GGt:3Kx-  
// output.writeLong(nPos); <B"M} Y>_P  
output.writeLong(fileSplitterFetch.nStartPos); fiG/"/u  
output.writeLong(fileSplitterFetch.nEndPos); GO3F[l  
} ii,/omn:  
output.close(); OZ,%T9vP  
} 01~&H8 =  
catch(IOException e){e.printStackTrace ();} r92C^h0  
catch(Exception e){e.printStackTrace ();} 3"9'MDKH  
} |^ K"#K  
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X%1j-;Wr@  
//读取保存的下载信息（文件指针位置） AiMD"7 )c  
private void read_nPos() e(t,~(  
{ !>olD_  
try{ pyvZ[R9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); cU`sA_f  
int nCount = input.readInt(); YS7R8|  
nStartPos = new long[nCount]; 5yC$G{yV  
nEndPos = new long[nCount]; AL(YQ)-Cg  
for(int i=0;i<nStartPos.length;i++) +aa( YGL  
{ /<J&ZoeJB  
nStartPos = input.readLong(); u>e4;f`F  
nEndPos = input.readLong(); 8 oK;Tzh  
} ?=C?3R  
input.close(); #:C?:RMS  
} }\p>h  
catch(IOException e){e.printStackTrace ();} y:\ ^[y IQ  
catch(Exception e){e.printStackTrace ();} Sw<V/t  
} o'9K8q\1  
HkH!B.H]  
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private void processErrorCode(int nErrorCode) 
#+X|,0p  
{ ]yzqBb
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System.err.println("Error Code : " + nErrorCode); m@qM|%(0x  
} _'g'M=E  
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.Vy*p")"  
//停止文件下载 {|
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public void siteStop() v7;zce/~  
{ Yn0l}=, n  
bStop = true; C&d%S|:IR  
for(int i=0;i<nStartPos.length;i++) >,ThIwRN  
fileSplitterFetch.splitterStop(); p^=>N9  
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} < C{-ph  
} &3jq'@6  
//负责部分文件的抓取 i{['18Q$F3  
**FileSplitterFetch.java 2<Vw :+,  
*/ HkGA$  
package NetFox; ~j1.;WId[  
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3 #fOrNU2  
import java.io.*; .Pp;%  
import java.net.*; OHz>B!`  
$~#N1 
 
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public class FileSplitterFetch extends Thread { 3$]SP1Mc(  
aWp9K+4R$/  
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String sURL; //File URL
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long nStartPos; //File Snippet Start Position nG0Uv%?{pj  
long nEndPos; //File Snippet End Position DXbzl +R  
int nThreadID; //Thread's ID 8 *Fr=+KN  
boolean bDownOver = false; //Downing is over c5>'1L  
boolean bStop = false; //Stop identical fS( )F*J  
FileAccessI fileAccessI = null; //File Access interface uO4kCK<7C  
Je|D]w  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %]>LnbM>4  
{ D.e4S6\&  
this.sURL = sURL; qr5ME/)z  
this.nStartPos = nStart; f8>S<:  
this.nEndPos = nEnd; &9Vm3X  
nThreadID = id; O2W EA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Tum9Xa  
} 'IaI7on  
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public void run() RETq S  
{ 2>s@2=Aq  
while(nStartPos < nEndPos && !bStop) nN|zEw]  
{ !PCw-&  
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try{ |+?ABPk"  
URL url = new URL(sURL); $Cr? }'a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 69Y>iPRU  
httpConnection.setRequestProperty("User-Agent","NetFox"); V^qZ~US  
String sProperty = "bytes="+nStartPos+"-"; 8]DN]\\o  
httpConnection.setRequestProperty("RANGE",sProperty); 97H2hYw9l  
Utility.log(sProperty); SE0"25\_G  
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InputStream input = httpConnection.getInputStream();
&Wj %`T{  
//logResponseHead(httpConnection); |TOz{  
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byte[] b = new byte[1024]; u~X]W3  
int nRead; WMB~? EDhv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^s@?\v  
{ /jI>=:z  
nStartPos += fileAccessI.write(b,0,nRead); MB<oWH[e)  
//if(nThreadID == 1) Jo1=C.V`Y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _7SOl.5ZE  
} 6gS<h\h0  
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Utility.log("Thread " + nThreadID + " is over!"); f1Ruaz-  
bDownOver = true; thk33ss:  
//nPos = fileAccessI.write (b,0,nRead); [YT"UVI  
} )j6VROt  
catch(Exception e){e.printStackTrace ();} $CaF"5}?Ke  
} =G*rfV@__V  
} 2Y&QJon)  
#vhxW=L`=  
CT6Ca,  
//打印回应的头信息 JLT^0wBB  
public void logResponseHead(HttpURLConnection con) g/+P]c6/  
{ |F36^  
for(int i=1;;i++) "}PaMR]  
{ 'xAfcP[^  
String header=con.getHeaderFieldKey(i); `B;^:u  
if(header!=null) qw[)$icP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8W?/Sg`  
Utility.log(header+" : "+con.getHeaderField(header)); \D BtU7"v  
else (3C6'Wt  
break; `[V]xP%V  
} ysA~Nq@  
} yG?,8!/]  
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public void splitterStop() S?nXpYr  
{ 5nIm7vlQm  
bStop = true; G S-@drZp_  
} <5MnF  
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} ?4wS/_C/
 
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/* vINm2%*zJ  
**FileAccess.java D`3m%O(?  
*//文件访问(定位，写) siw } }}  
package NetFox; \I; lgz2  
import java.io.*; Cul^b_UmP#  
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public class FileAccessI implements Serializable{ jdV E/5  
LhC%`w  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 x
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RandomAccessFile oSavedFile; N~L3 9  
long nPos; E$m3Gg)s>N  
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public FileAccessI() throws IOException W!4(EdT*Cq  
{ roYoxF;\  
this("",0); fk,[`n+  
} J3cbDE%^m  
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public FileAccessI(String sName,long nPos) throws IOException %,$/wh)<V  
{ @ae;&  
oSavedFile = new RandomAccessFile(sName,"rw"); mR:G,XytxM  
this.nPos = nPos; g76l@QYIU  
oSavedFile.seek(nPos);  UN[rW0*  
} +{N LziO  
\Fj$^I
>C  
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public synchronized int write(byte[] b,int nStart,int nLen) ST1PSuC~  
{ f.cIhZF  
int n = -1; OoTMvZ
P[  
try{ XzGPBi  
oSavedFile.write(b,nStart,nLen); zz3Rld!b[  
n = nLen; #`)zD"CO  
} _]H$rf,Rc  
catch(IOException e) IM),cOp=  
{ )?RR1P-ID  
e.printStackTrace (); o,(MB[|hQ  
} WgPpW!`  
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return n; We%-?l:"  
} )B.NV<m  
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} l/0TNOA  
9{_D"h}}  
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/* B]~#+rMK  
**SiteInfoBean.java `G
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*/ cN_e0;*Ua  
package NetFox; \xJTsdd  
/Ps}IW  
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public class SiteInfoBean { :J` *@cDn  
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private String sSiteURL; //Site's URL >:%YAR`  
private String sFilePath; //Saved File's Path W#!![JDc  
private String sFileName; //Saved File's Name ZOvMA]Rf  
private int nSplitter; //Count of Splited Downloading File 9^l_\:4  
_UKH1qUd4  
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public SiteInfoBean() m:A7*r[  
{//nSplitter的缺省值为5 L9[? qFp  
//default value of nSplitter is 5 9NLO{kN  
this("","","",5); f@lRa>Z(Fm  
} {tn%HK">  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) H~x,\|l#  
{ 'zV/4iE=  
sSiteURL= sURL; r168ft?c  
sFilePath = sPath; |Z}uN!Jm  
sFileName = sName; Jx[Z[RO2  
this.nSplitter = nSpiltter; o mstJ9  
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#"% ]1={b  
} \Ku6gEy  
C=2"*>lTn  
4Sv&iQ=vh  
public String getSSiteURL() ,p6X3zY  
{ [X[d`@rXv  
return sSiteURL; \:ntqj&A|  
} }TD$!  
7Fb |~In<Z  
8_WFSF^  
public void setSSiteURL(String value) >Z ZX]#=I  
{ 0kP,Z
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sSiteURL = value; &qqS'G*  
} Uv'.]#H<  
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"QA <5P  
public String getSFilePath() u(V4KUk  
{ AA34JVm]  
return sFilePath; RbUBKMZU  
} +`g&J  
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7Wub@Mp  
public void setSFilePath(String value) 6( TG/J  
{ <*u[<  
sFilePath = value; _uU}J5d.  
} ~3
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]5b%r;_  
%IGcn48J  
public String getSFileName() lgp-/O"T  
{ biFy*+|  
return sFileName; F<y$Q0Z}  
} j2NnDz'  
o =)hUr  
I8 Ai_^P  
public void setSFileName(String value) mf]1mG})  
{ 513{oM:  
sFileName = value; g@]G [(  
} +4U?*:n  
T.nY>Q8  
{X$8yy2zC5  
public int getNSplitter() 16=tHo8|  
{ Z"rrbN1  
return nSplitter; G\3@QgyQ  
} |,rIB
 
7@"J&><w!  
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public void setNSplitter(int nCount) `oH=O6  
{ Qm86!(eZ-  
nSplitter = nCount; m/l#hp+  
} ,&$=2<Dx  
} 9qxB/5d_  
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/* g2p/#\D\J  
**Utility.java </0@7  
*/ !IlsKMZ  
package NetFox; a!YpSFr  
 mD`
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*ZP
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public class Utility { cSy{*K{B  
A+i|zo5p=k  
KO/Z|I  
public Utility() 3n-~+2l  
{ 9fR`un)f}  
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} R<aF;Rvb5  
j8kax/*[  
//线程睡眠 Q$Y ]KV  
public static void sleep(int nSecond) h3y0bV[g=  
{ FWpcWmS`s  
try{ m":lKXpQ  
Thread.sleep(nSecond); IfF@$eO  
} *|S.[i_7  
catch(Exception e) `!{m#BBT}  
{ $w{!}U2+-  
e.printStackTrace (); x#z}A&  
} %7WQb]y  
} }nNZp  
Kp[
 F@A#  
//日志 Ul#||B .c{  
public static void log(String sMsg) 6}bUX_!&s  
{ b z3&  
System.err.println(sMsg); n<47#-  
} Bu4J8eLx  
PScq-*^  
t.'|[pOV  
public static void log(int sMsg) |E:q!4?0  
{ #;ezMRKM"  
System.err.println(sMsg); =@w,D.5h  
} Cz@[l=-T7  
} 4E[ 9)n+YV  
P9(]9np,,  
L
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/* c\.Hs9T >  
**TestMethod.java T;/Y/Fd  
*/ ?`R;ZT)U-  
package NetFox; LJ7Qwh_",  
3D<s
#  
dd4g?):  
public class TestMethod { 3Z.<=D  
&K Ti[  
*h59Vaoc  
public TestMethod() {=n-S2%  
{ ///xx/weblogic60b2_win.exe ;OjxEXaq  
try{ x>MrB  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -90qG"@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); I75>$"$<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *N5cC#5`=  
fileFetch.start(); w\wS?E4G  
} )+ }\NCFh  
catch(Exception e){e.printStackTrace ();} D*!p8J8Ku  
<)01]lKH  
*xY}?vSs  
} yTj!(C  
LU$aCw5 B;  
v5J% p4  
public static void main(String[] args) h>>KH*dQ  
{ AC*> f&  
new TestMethod(); WDznhMo  
} J,@SSmJ`  
} "[W${q+0x  
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