http断点续传简单实现（java)

/* 7&etnQJ{  
**SiteFileFetch.java YA+R!t:F{  
*/ , MqoX-+  
package NetFox; 9[~.{{Y  
import java.io.*; PQi(Oc  
import java.net.*; l^tRy_T:-  
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public class SiteFileFetch extends Thread { \Dr( /n  
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SiteInfoBean siteInfoBean = null; //文件信息Bean !`H!!Kg0L  
long[] nStartPos; //开始位置 w}/+3z  
long[] nEndPos; //结束位置 p1GP@m,^n0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `}ZtK574  
long nFileLength; //文件长度 18~jUYMV  
boolean bFirst = true; //是否第一次取文件 Z9MU%*N  
boolean bStop = false; //停止标志 Le-t<6i-V#  
File tmpFile; //文件下载的临时信息 uQ ]ZMc  
DataOutputStream output; //输出到文件的输出流 <QgpePyoN  
1.,KN:qe  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） t\:=|t,  
public SiteFileFetch(SiteInfoBean bean) throws IOException <2O#!bX1  
{ "\lOOp^-  
siteInfoBean = bean; v!DU ewz  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y]!#$C /  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e~he#o[%a  
if(tmpFile.exists ()) >C{8}Lg-.  
{ {Gh9(0,B?  
bFirst = false; jc32s}/H  
read_nPos(); +u |SX/C  
} m+dQBsz\  
else u>] )q7s  
{ 25 U+L  
nStartPos = new long[bean.getNSplitter()]; =^zGn+@z  
nEndPos = new long[bean.getNSplitter()]; 4K~>  
} $BLd>gTzmv  
/&qE,>hd.+  

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} @}r s6 G  
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public void run() i6FJG\d  
{ CG3
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//获得文件长度 =Y
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//分割文件 /A>nsN?:]  
//实例FileSplitterFetch 6c>:h)?  
//启动FileSplitterFetch线程 <RbsQ^U  
//等待子线程返回 4"nYxL"<4  
try{ .
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if(bFirst) Gf!c  
{ 2#qcYU  
nFileLength = getFileSize(); CCC9I8rZD  
if(nFileLength == -1) 1JOoICjB  
{ JS?%zj&@  
System.err.println("File Length is not known!"); C!1)3w|  
} %LqT>HXJ  
else if(nFileLength == -2) WK0IagYw  
{ F *U.cJ%  
System.err.println("File is not access!"); 3C;;z  
} D2Q0p(#%  
else 7uu\R=$  
{ S
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for(int i=0;i<nStartPos.length;i++) ,l,q;]C%  
{ I4<_y5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1=X1<@*  
} qx0F*EH|  
for(int i=0;i<nEndPos.length-1;i++) A[F@rUZp  
{ 0a!|*Z  
nEndPos = nStartPos[i+1]; W8-vF++R  
} BNO+-ob-  
nEndPos[nEndPos.length-1] = nFileLength; X-CoC   
} X_3hh}=  
} oZL# *Z(h  
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2J)  
//启动子线程 6@:<62!;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D)[(  
for(int i=0;i<nStartPos.length;i++) pOB<Bx5t  
{ y34<B)Wy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5]kv1nQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), XQOM6$~,  
nStartPos,nEndPos,i); }:s.m8LC5n  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Xe\v6gbD  
fileSplitterFetch.start(); $&jVEMia  
} <|E*aR|M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VTX6_&Hc1g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); bq8h?Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", fCX8s(
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nEndPos = " + nFileLength); qJ~fEX  
// fileSplitterFetch[nPos.length-1].start(); 7?vj+1;  
S*76V"")  
HqyAo]{GN  
//等待子线程结束 JZ> (h  
//int count = 0; Zx: h)I  
//是否结束while循环 j(>xP*il  
boolean breakWhile = false; ZP0D)@8  
^8dCFw.rU  
]1[:fQF7/L  
while(!bStop) .E7"Lfs-  
{ Mlbc
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write_nPos(); Z(LTHAbBk|  
Utility.sleep(500); <<Z, 1{3F  
breakWhile = true; >$a;+v  
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$:A80(#+  
for(int i=0;i<nStartPos.length;i++) }YM[aq?6  
{ C/9]TkX}q  
if(!fileSplitterFetch.bDownOver) CZ{7?:^f  
{ ^/}&z  
breakWhile = false; {DUtdu[  
break; u&o$2 '8  
} {([`[7B>a<  
} nuA 0%K  
if(breakWhile) F]0 qt$GO  
break; o?IrDQ2gmh  
Czy}~;_Ay  
E},zB*5TH  
//count++; ]9W7]$  
//if(count>4) 5e?<x>e  
// siteStop(); tCwB7c-  
} R. vV
l+  
/wP2Wnq$  
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System.err.println("文件下载结束！"); )NqRu+j  
} 8NJT:6Q7l  
catch(Exception e){e.printStackTrace ();} [1z.JfC :S  
} :"@-Bcln  
8L6b:$Y3@C  
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//获得文件长度 h7o.RRhK  
public long getFileSize() $Fy>N>,E(  
{ $
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int nFileLength = -1; T)ISDK4>S"  
try{ M[Nv>  
URL url = new URL(siteInfoBean.getSSiteURL()); h 'Hnq m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ua=r24fy  
httpConnection.setRequestProperty("User-Agent","NetFox"); xZ>j Q_}  
<zAYq=IU  
ip1gCH/?_+  
int responseCode=httpConnection.getResponseCode(); N8J(RR9O  
if(responseCode>=400) )me`Ud
 
{ 2Je]dj4  
processErrorCode(responseCode); -_O jiQR  
return -2; //-2 represent access is error i1bmUKZ8'L  
} #ZP;] W  

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String sHeader; ' d?6 L  
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for(int i=1;;i++) Zp9kxm'  
{ >6)|>#Wi  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); lJT"
aXt'M  
//Utility.log(in.readLine()); 7;&,LH  
sHeader=httpConnection.getHeaderFieldKey(i); f"zmNG'  
if(sHeader!=null) ,g,Hb\_R)  
{ cRWB`&  
if(sHeader.equals("Content-Length")) pmO0/ty  
{ i` ay9J8N  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,@Kn@%?$  
break; %hdjQIH  
} 2Vw2r@S/  
} 'G>9iw  
else /{W6]6^  
break; l(@c  
} :-$8u;!M  
} N0JdU4'  
catch(IOException e){e.printStackTrace ();} ,(f W0d#  
catch(Exception e){e.printStackTrace ();} Ed2A\S6tl  
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HIC!:|  
Utility.log(nFileLength); Htln <N  
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return nFileLength; SQ/HZ  
} A5%$<  
,H^!G\  
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//保存下载信息（文件指针位置） ;y50t$0  
private void write_nPos() Fmz+ Xb  
{ g-]~+7LL  
try{ *-{|m1P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); m4Ue)  
output.writeInt(nStartPos.length); *;~u 5y2b  
for(int i=0;i<nStartPos.length;i++) U=U5EdN;  
{ AYpvGl'  
// output.writeLong(nPos); (oG.A  
output.writeLong(fileSplitterFetch.nStartPos); j-DWz>x  
output.writeLong(fileSplitterFetch.nEndPos); pVrY';[,|  
} Uqy/~n-v<  
output.close(); e0otr_)3F  
} %~PT7"4  
catch(IOException e){e.printStackTrace ();} }&==;7,O  
catch(Exception e){e.printStackTrace ();} \j3dB tc  
} ?,8+1"|$A]  
ju.pQ=PSX  
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//读取保存的下载信息（文件指针位置） a(D=ZKbVU  
private void read_nPos() 9
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{ ~131|e`C  
try{ p8?v o?^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >}W[>WReI  
int nCount = input.readInt(); HXztEEK6  
nStartPos = new long[nCount]; =  
nEndPos = new long[nCount]; J_-fs#[x  
for(int i=0;i<nStartPos.length;i++) vLyazVj..  
{ B&0W P5OF  
nStartPos = input.readLong(); %~gI+0HK  
nEndPos = input.readLong(); <V Rb   
} .>P:{''  
input.close(); QG2 Zh9R  
} ^NRf  
catch(IOException e){e.printStackTrace ();} D}j`T  
catch(Exception e){e.printStackTrace ();} cC+2%q B  
} `|nCnT'  
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private void processErrorCode(int nErrorCode) Pnm$g;`P  
{ 1?1Bz?EKF*  
System.err.println("Error Code : " + nErrorCode); SY%y*6[6  
} 0y?;o*&U\  
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//停止文件下载 UxzF5V5  
public void siteStop() 2Q5@2jT  
{ Hbd>sS  
bStop = true; 1 <+aF,  
for(int i=0;i<nStartPos.length;i++) +}a(jO  
fileSplitterFetch.splitterStop(); Jww#zEK  
X;Sb^c"j1  
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} lG%697P  
} +A)> zx  
//负责部分文件的抓取 ?+.C@_QZQ  
**FileSplitterFetch.java }u=Oi@~  
*/ ^2+Vt=*  
package NetFox; .9PT)^2  
) ba~7A  
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import java.io.*; g$?^bu dxv  
import java.net.*; Q{L:pce
-  
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public class FileSplitterFetch extends Thread { ^879sI  
>X'-J{4R  
WKlyOK=}  
String sURL; //File URL k
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long nStartPos; //File Snippet Start Position [H>u'fy:C  
long nEndPos; //File Snippet End Position 3?I!  
int nThreadID; //Thread's ID wlaPE8Gc  
boolean bDownOver = false; //Downing is over "QxULiw  
boolean bStop = false; //Stop identical \y]K]iv  
FileAccessI fileAccessI = null; //File Access interface n$r`s`}  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4n7Kz_!SVf  
{ ._^ne=Lx  
this.sURL = sURL; L-C^7[48=  
this.nStartPos = nStart; 9Ffam#  
this.nEndPos = nEnd; s(3HZ>qx;  
nThreadID = id; H@?} !@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'ET];iZ2  
} o,dp{+({  
h\w;SDwOk  
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public void run() 7Y(Dg`8G  
{ \&;y:4&l8  
while(nStartPos < nEndPos && !bStop) xd^Pkf  
{ ~$5XiY8A  
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i\ X3t5  
try{ +KIz#uqF8Z  
URL url = new URL(sURL); X~0-WBz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); YRX^fZ-b  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,v>;/qm  
String sProperty = "bytes="+nStartPos+"-"; %\HPYnIe  
httpConnection.setRequestProperty("RANGE",sProperty); 8Sj<,+XFq  
Utility.log(sProperty); wGKxT ap  
"T5oUy&i  
a
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InputStream input = httpConnection.getInputStream(); qpYgTn8l7  
//logResponseHead(httpConnection); vf{$2rC  
4=Ru{ewRV  
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byte[] b = new byte[1024]; ~44u_^a  
int nRead; XxS#~J?:_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &zX W  
{ H/x0'  
nStartPos += fileAccessI.write(b,0,nRead); ?4/pE@RIy  
//if(nThreadID == 1) J'X}6Q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4J_HcatOB  
} Yr_B(n  
xsj,l@Ey  
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Utility.log("Thread " + nThreadID + " is over!"); &AJkYh  
bDownOver = true; N'WTIM3W  
//nPos = fileAccessI.write (b,0,nRead); vHcl7=)Q  
} 6dr
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catch(Exception e){e.printStackTrace ();} \EVT*v=}/  
} x,25ROaHY  
} y 2> 93m  
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SefhOh^,V  
//打印回应的头信息 Kgr<OL}VJ  
public void logResponseHead(HttpURLConnection con) *pa hZiO  
{ :p/=KI_  
for(int i=1;;i++) )LFbz#;Y  
{ I!*P' {lh  
String header=con.getHeaderFieldKey(i); B]G2P`sN  
if(header!=null) ]A%3\)r  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0j!3\=P$  
Utility.log(header+" : "+con.getHeaderField(header)); NeY*l  
else 1n^N`lD8]6  
break; 20|_wAA5  
} !<:Cd(bM  
} XKky-LeJ  
<$z[pw<  
#C&';HB;y  
public void splitterStop() s_NY#MPz[  
{ X1.-C@o  
bStop = true; '2lzMc>wvP  
} 0<!9D):Bb  
`~)?OTzU#  
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} #RR;?`,L}  
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~F'6k&A^q  
/* yO%^[c?  
**FileAccess.java r4SwvxhG  
*//文件访问(定位，写) N)g_LL>^  
package NetFox; $J4\jIipL  
import java.io.*; ~O\A 0e  
VtLRl0/  
O^8ZnN_+  
public class FileAccessI implements Serializable{ /e>%yq<9B  
D=z~]a31!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -\f7qRW^U  
RandomAccessFile oSavedFile; #17 &rizl  
long nPos; :VlA2Ih&q  
q"2APvsvp  
1cOR?=G~  
public FileAccessI() throws IOException Pq [_(Nt  
{ DfAF-Yhut  
this("",0); i6_}  
} Ct)58f2  
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pV ^+X}  
public FileAccessI(String sName,long nPos) throws IOException ZMgsuzg  
{ 5`p9Xo>)yW  
oSavedFile = new RandomAccessFile(sName,"rw"); yR>
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this.nPos = nPos; qG;tD>jy  
oSavedFile.seek(nPos); ZcX
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} T
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;
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public synchronized int write(byte[] b,int nStart,int nLen)  wkZwtq  
{ ,gQl_Amvz  
int n = -1; uxTgK'3  
try{ <7U~0@<Y  
oSavedFile.write(b,nStart,nLen); b&[".ibN1  
n = nLen; &!/>B .  
} )^o.H~Pv  
catch(IOException e) ?m*e$!M0  
{ NuR7pjNMZ  
e.printStackTrace (); :38{YCN  
} d|RUxNjM-J  
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-8qCCV&1i  
return n; 1}\p:`  
} 3Sfd|0^  
k^%=\c  
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} ; H ;h[
 
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/* h-ii-c?R@0  
**SiteInfoBean.java r!Dk_|Cd  
*/ gf8o~vKX$G  
package NetFox; %evb.h)  
aNu.4c/5  
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public class SiteInfoBean { @)h>vg  
Yg.[R] UC  
HZ'rM5Kq  
private String sSiteURL; //Site's URL F@Sk=l(  
private String sFilePath; //Saved File's Path z<55[~3  
private String sFileName; //Saved File's Name F&wAre<  
private int nSplitter; //Count of Splited Downloading File mh}D[K=~%  
LH4#p%Pb%  
nu\AEFT  
public SiteInfoBean() gJ|#xZ
 
{//nSplitter的缺省值为5 %.=}v7&<z  
//default value of nSplitter is 5 !lfE7|\p  
this("","","",5); Vpg>K #w  
} t~ {O)tt
 
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qa^cJ1@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Kc\8GkdB  
{ nIg 88*6b,  
sSiteURL= sURL; +w]#26`d  
sFilePath = sPath; Cik1~5iF  
sFileName = sName; As46:<!2  
this.nSplitter = nSpiltter; <w^u^)iLy1  
-O$vJ,*  
H};1>G4  
} ]?(kaNQ"D  
v1{j1~Z
R  
n{TWdC  
public String getSSiteURL() o~XK*f=(  
{ A*DN/lG  
return sSiteURL; D-{*3?x  
} 1@OpvO5  
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public void setSSiteURL(String value) Qq:}Z7 H  
{ Q$5t~*$`  
sSiteURL = value; 4\-11!'08  
} =?C <@  
k( 0;>)<i  
nRBS&&V  
public String getSFilePath() 6,YoP|@0  
{ 3zh:~w_  
return sFilePath; :8@)W<
>%  
} 2p, U ^h  
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v Z]j%c@  
public void setSFilePath(String value) SWzqCF  
{ n}a`|Nbk  
sFilePath = value;
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} @Pcgm"H<  
m"~ddqSMT  
crv#IC2  
public String getSFileName() .;7V]B1o  
{ d\>XfS  
return sFileName; -& (iU
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} sf2%WPK  
e;XRH<LhAU  
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public void setSFileName(String value) V$hL\`e  
{ Mbxl{M >  
sFileName = value; d;dT4vx$[M  
} ZS+m}.,whQ  
H8w[{'Mei  
@H`jDaB9  
public int getNSplitter() ZX&e,X~V  
{ pZS]i "  
return nSplitter; -crMO57/  
} 3r+c&^  
/b>xQ.G  
Ph P)|P  
public void setNSplitter(int nCount) ~4+Y BN  
{ /(8"]f/  
nSplitter = nCount; 4eB'mPor  
} L[2N zwO  
} w` +,  
+H&/C1u  
1,=:an  
/* )zO|m7  
**Utility.java 8F>9CO:&N  
*/ ?{'_4n3O  
package NetFox; z$^wCd:  
2o(O`;z  

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public class Utility { *e [*  
Ut2T:%m{  
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public Utility() @>(JC]HtR  
{ kAp#6->(q  
v CsE|eMP  
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} ;!f~  
`r1j>F7Xb  
//线程睡眠 VB905%  
public static void sleep(int nSecond) F#|y,<}<  
{ ahgP"Qz  
try{ <k8WnA ~Fl  
Thread.sleep(nSecond); T+T)~!{%  
} F1BvDplQ>G  
catch(Exception e) NpGi3>5  
{ 8B-PsS|'  
e.printStackTrace (); EE]xZz>o  
} 1/mBp+D  
} >[wxZ5))  
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//日志 v`mB82s  
public static void log(String sMsg) Q0"?TSY  
{ >dK0&+A  
System.err.println(sMsg); G.O;[(3ab  
} neu<zSS  
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Vp; `!+z"  
public static void log(int sMsg) +mBS&FK  
{ to).PI?  
System.err.println(sMsg); r&xIVFPI[  
} GmNCw5F  
} e~gNGr]L/  
K?,?.!ev
 
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/* #f(tzPD  
**TestMethod.java T\Xf0|y  
*/ #xx.yn(7  
package NetFox; <;#gcF[7>  
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Da)p%E>Q  
public class TestMethod { -flcB|I`  
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.0yBI=QI  
public TestMethod() *\#<2 QAe  
{ ///xx/weblogic60b2_win.exe "uuM#@h  
try{ U*{0,Ue'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =LIb0TZ2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); bx2<WdLyT  
SiteFileFetch fileFetch = new SiteFileFetch(bean); bn|HvLQ"1  
fileFetch.start(); ncadVheKt  
} 1E!.E=Y?M  
catch(Exception e){e.printStackTrace ();} ylos6]zS8  
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z l`m1k-X  
} au19Q*r9  
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public static void main(String[] args) =#4>c8MM  
{ /zh:7N  
new TestMethod(); Ie!">8."  
} }BW&1*M{  
} .!^O
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