http断点续传简单实现（java)

/* j""I,$t  
**SiteFileFetch.java sGIY\
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*/ 6|U0"C#]  
package NetFox; &Im{p7gf!b  
import java.io.*; Vm.&JVb  
import java.net.*; eUvIO+av  
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public class SiteFileFetch extends Thread { $,ev <4I&  
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SiteInfoBean siteInfoBean = null; //文件信息Bean QjETu  
long[] nStartPos; //开始位置 xZjl_bJ  
long[] nEndPos; //结束位置 iorKS+w"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 
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long nFileLength; //文件长度 h: :'s&|  
boolean bFirst = true; //是否第一次取文件 evf){XhT;n  
boolean bStop = false; //停止标志 :kSA^w8  
File tmpFile; //文件下载的临时信息 dDN#>|  
DataOutputStream output; //输出到文件的输出流 ay6G1\0W  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Be+'&+  
public SiteFileFetch(SiteInfoBean bean) throws IOException BMU}NZA  
{ $Tu%dE(OF  
siteInfoBean = bean;  r(pp =  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); V x1C4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); FH}n]T  
if(tmpFile.exists ()) uyP)5,  
{ f9H;e(D9]  
bFirst = false; jEfrxlj  
read_nPos(); pc&/'zb  
} vC~];!^  
else VVeO>jd  
{ 1\q(xka{  
nStartPos = new long[bean.getNSplitter()]; Sr~zN:wn  
nEndPos = new long[bean.getNSplitter()]; (8o~ XL  
} yrO'15
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} V1Dwh@iS  
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public void run() PCnE-$QH  
{ K^tM$l\  
//获得文件长度 x|*v(,7b]!  
//分割文件 *A2J[,?c  
//实例FileSplitterFetch gWA)V*}f  
//启动FileSplitterFetch线程 I z~#G6]M  
//等待子线程返回 a`(6hL3IT  
try{ /_v5B>  
if(bFirst) !zLd,`  
{ *%(8z~(\  
nFileLength = getFileSize(); v=nq P{  
if(nFileLength == -1) =IV_yor  
{ ])}{GW  
System.err.println("File Length is not known!"); &H,5f#  
} W3*BdpTw  
else if(nFileLength == -2) @B5@3zYs  
{ Yo;/7gG>  
System.err.println("File is not access!"); OQaM47"  
}  Z_F:H@-&  
else .:Bjs*
 
{ w
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for(int i=0;i<nStartPos.length;i++) 6~?7CK  
{ a#FkoA~M  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); C
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} rklr^ e  
for(int i=0;i<nEndPos.length-1;i++) 3;~1rw=$<  
{ o%X_V!B{V  
nEndPos = nStartPos[i+1]; 4IG=mG)  
} >x@]wsj  
nEndPos[nEndPos.length-1] = nFileLength; W%b<(T;  
} %1SA!1>j  
} aq~hl7MTj  
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hXM8`iFW5  
//启动子线程 ~\4l*$3(^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )v;>6(  
for(int i=0;i<nStartPos.length;i++) AuUT 'E@E  
{ w_pEup\`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m9ts&b+TE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F6h3M~uR  
nStartPos,nEndPos,i); K+Q81<X~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %]nYv#K  
fileSplitterFetch.start(); D|Wekhm  
} ,0NVb7F;k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rZ 9bz}K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Fwyv>U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [VIdw92  
nEndPos = " + nFileLength); </tiNc  
// fileSplitterFetch[nPos.length-1].start(); Gnp,~F"  
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rmpJG|(  
//等待子线程结束 ?l`DkUo*j  
//int count = 0; j(F%uUpN  
//是否结束while循环 QZef=  
boolean breakWhile = false; 'VFxg,  
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while(!bStop) >WE3$Q>bi  
{ fF[n?:VV  
write_nPos(); |TF,Aj  
Utility.sleep(500); \D?6_ ,O  
breakWhile = true; f}^}d"&F  
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for(int i=0;i<nStartPos.length;i++) (ZQ{%-i?qR  
{ ]8ua>1XS  
if(!fileSplitterFetch.bDownOver) j+]>x]c0  
{ nf+8OH7  
breakWhile = false; $EW31R5h<s  
break; )52:@=h*l  
} )XMSQ ="m  
} ps"crV-W  
if(breakWhile) cKh
{ s  
break; f<9H#S:  
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.  
//count++; ,$Qa]UN5Q  
//if(count>4) QXishHk&  
// siteStop(); v3Tr6[9  
} J6Hw05%0=  
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System.err.println("文件下载结束！");  ;4 R1  
} vmAMlgZ8{<  
catch(Exception e){e.printStackTrace ();} `j0T[Pi  
} 1lfkb1BM  
bM_Y(TgJ  
f%ZqK_CW  
//获得文件长度 H:#b(&qw2  
public long getFileSize() ?(Dkh${@  
{ 4LtFv)i  
int nFileLength = -1; K6@QZc5.!  
try{ I8gGP'  
URL url = new URL(siteInfoBean.getSSiteURL()); eJilSFp1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5g&.P\c{  
httpConnection.setRequestProperty("User-Agent","NetFox"); PP/M-Jql)  
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int responseCode=httpConnection.getResponseCode(); CY)/1 # J  
if(responseCode>=400) If\u^c  
{ qW6a|s0}  
processErrorCode(responseCode); 9@./=5N~3  
return -2; //-2 represent access is error A|CW4f,  
} 5xwztcR-  
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String sHeader; g)!B};AA  
 IKKd  
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for(int i=1;;i++) R3d>|`) +  
{ yX$I<L<Suz  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %CfJ.;BDNE  
//Utility.log(in.readLine()); apF!@O^}y  
sHeader=httpConnection.getHeaderFieldKey(i); AW&HWc~A  
if(sHeader!=null) 9'o!9_j  
{ cE/
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if(sHeader.equals("Content-Length")) "u Xl  
{ C&bw1`XJf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 699z@>$}
 
break; Z8(1QU,~2  
} W tnZF]1:u  
} *;Dd:D9  
else 1s-k=3)  
break; skR/Wf9DH  
} iUi{)xa2  
} Pr{?A]dQ  
catch(IOException e){e.printStackTrace ();} ?Bq"9*q  
catch(Exception e){e.printStackTrace ();} -6;0 x  
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Utility.log(nFileLength); P_j?V"i<  
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return nFileLength; Z_}vjk~s  
} xM9EO(u  
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X |.'_6l.  
//保存下载信息（文件指针位置） 'C1=(PE%`  
private void write_nPos() Vg#s  
{ 3Ku!;uo!u  
try{ ] ^tor
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); G`ZpFg0Y  
output.writeInt(nStartPos.length); ve.iyr  
for(int i=0;i<nStartPos.length;i++) n}7DL8  
{ V=VL@=  
// output.writeLong(nPos); +&jWM-T"-  
output.writeLong(fileSplitterFetch.nStartPos); u ?7(A%  
output.writeLong(fileSplitterFetch.nEndPos); sT[)r]`T  
} QN9$n%Z  
output.close(); l:a+o gm3  
}  LS,/EGJ  
catch(IOException e){e.printStackTrace ();} bESmKe(  
catch(Exception e){e.printStackTrace ();} MxuwEV|^  
} ik+qx~+`Qv  
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4-eb&
 
//读取保存的下载信息（文件指针位置） 0L$v7
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private void read_nPos() L5
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{ '
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try{ Nm--h$G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _J6|ju\  
int nCount = input.readInt(); HelC_%#^  
nStartPos = new long[nCount]; 3%/]y=rA  
nEndPos = new long[nCount]; .6!IO^`[  
for(int i=0;i<nStartPos.length;i++) r) T^ Td1  
{ <GF)5QB  
nStartPos = input.readLong(); <^UB@'lCm  
nEndPos = input.readLong(); F8;M+
+  
} TYw0#ZXo  
input.close(); g^NdN46%  
} g.kpUs  
catch(IOException e){e.printStackTrace ();} k~>9,=::d  
catch(Exception e){e.printStackTrace ();} /R^HRzTO  
} ! W$u~z  
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private void processErrorCode(int nErrorCode) 7I/Sfmqy"O  
{ -g]/Ko]2@$  
System.err.println("Error Code : " + nErrorCode); x +!<_p  
} V2ypmkn8&  
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//停止文件下载 U`,&Q]  
public void siteStop() GD}3r:wDs  
{ i)1E[jc{p!  
bStop = true; Un]`
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for(int i=0;i<nStartPos.length;i++) kWF4k  
fileSplitterFetch.splitterStop(); Hig=PG5I  
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} /_rQ>PgSZW  
} (s %T18  
//负责部分文件的抓取 i92{N$*x  
**FileSplitterFetch.java &jl'1mZ  
*/ :@wO' o  
package NetFox; HPCzh  
l#7,<@)  
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import java.io.*; pco~Z{n  
import java.net.*; Xl#vVyO  
iVd*62$@$  
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public class FileSplitterFetch extends Thread { +o?.<[>!GR  
h.%VWsAO7  
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String sURL; //File URL HyiuU`  
long nStartPos; //File Snippet Start Position VD,F?L!  
long nEndPos; //File Snippet End Position &"._%S58V  
int nThreadID; //Thread's ID yH|ucN~k5S  
boolean bDownOver = false; //Downing is over T73oW/.0X?  
boolean bStop = false; //Stop identical ZF51|b  
FileAccessI fileAccessI = null; //File Access interface .lb2`!'r&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException '# "Z$  
{ Fh?;,Z  
this.sURL = sURL; >L$y|8O  
this.nStartPos = nStart; s^^X.z ,  
this.nEndPos = nEnd; 5w gtc~  
nThreadID = id; +#6WORH0S  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Umm_FEU#]  
} YZ7rs]A  
R# 8D}5[&  
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public void run() 5dMIv<#T`  
{ %Wom]/&,'  
while(nStartPos < nEndPos && !bStop) s2@N&7"u)  
{ u%V=Ze  
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try{ UX41/# 4  
URL url = new URL(sURL); .Y&_k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U#-&%|b$  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~1S7\e7{  
String sProperty = "bytes="+nStartPos+"-"; itm;,Sbg  
httpConnection.setRequestProperty("RANGE",sProperty); `kwyF27v]  
Utility.log(sProperty); *na7/ysT<  
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InputStream input = httpConnection.getInputStream(); xii*"n
~  
//logResponseHead(httpConnection); ]b'K BAMy  
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byte[] b = new byte[1024]; $P^=QN5Bb  
int nRead; +=$\7z>s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .#zx[Io  
{ %;yo\  
nStartPos += fileAccessI.write(b,0,nRead); v%/8pmZw;  
//if(nThreadID == 1) 6"|PJ_@P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q&MZ/Nnf  
} 6aM`qz)  
8hQ"rrj+  
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Utility.log("Thread " + nThreadID + " is over!"); Cs^o- g!L  
bDownOver = true; PP.k>zsx  
//nPos = fileAccessI.write (b,0,nRead); '$ s:cS`=  
} (dpBGt@  
catch(Exception e){e.printStackTrace ();} L0UAS'hf  
} KFAB  
} 9=rYzA?)+  
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,<R/x
[  
//打印回应的头信息 IqfR`iAix  
public void logResponseHead(HttpURLConnection con) cOOPNa>5_  
{ ?b#/*T}ac  
for(int i=1;;i++) _L_SNjA_  
{ &m'O :ZS2  
String header=con.getHeaderFieldKey(i); >7vSN<w~m  
if(header!=null) -hQ=0h~\B.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7vNS@[8  
Utility.log(header+" : "+con.getHeaderField(header)); T(a*d7  
else O_-.@uo./(  
break; cC"7Vt9b  
} 'V4.umj1~  
} VEpIAC4  
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public void splitterStop() S&_ZQLiQ$  
{ _]j=[|q 9  
bStop = true; `gfK#0x#  
} /J/r62  
H
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} @*is]d+Ya  
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/* M[<O]p6  
**FileAccess.java t^8#~o!%  
*//文件访问(定位，写) RZOk.~[v  
package NetFox; J-Sf9^G  
import java.io.*; '!yyg#  
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public class FileAccessI implements Serializable{ }mu8fm'  
dam.D.o"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 U!3nn#!yE  
RandomAccessFile oSavedFile; 6XFO@c}d  
long nPos; [<wy@W  
/PPk p9H{  
#kLM=a/_NO  
public FileAccessI() throws IOException g0g/<Tv[  
{ lCd^
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this("",0); #0!C3it6c  
} Y8\Ms^rz  
\Q^\z   
+=\S"e[F  
public FileAccessI(String sName,long nPos) throws IOException SkvKzV.R;  
{ Cgq9~U !  
oSavedFile = new RandomAccessFile(sName,"rw"); qpp:h_E  
this.nPos = nPos; :w:5;cmV  
oSavedFile.seek(nPos); ]Y;$~qQ  
} -6+HA9zz@C  
pNVao{::5  
[C771~BL>  
public synchronized int write(byte[] b,int nStart,int nLen) ~{2@-qcm  
{ SB$~Btr  
int n = -1; *aG0p&n}  
try{ V X211U.Q  
oSavedFile.write(b,nStart,nLen); -[^wYr=  
n = nLen; (e F5?I  
} ^,U&v;  
catch(IOException e) %}'sFum`  
{ F4bF&% R  
e.printStackTrace (); <=A&y5o  
} _QXo4z!a8  
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return n; JXPn <  
} @o;m!CYB  
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} 61jDI^:  
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V#3VRh  
/* ;`F0 %0d  
**SiteInfoBean.java RL)'m  
*/ )}?dYk  
package NetFox; !my5-f>{(  
9]AKNQq m  
?#FAa,  
public class SiteInfoBean { ^e&
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s-8>AW ep  
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private String sSiteURL; //Site's URL ?hfosBn&[  
private String sFilePath; //Saved File's Path T}u'  
private String sFileName; //Saved File's Name 1$Eiv8xd  
private int nSplitter; //Count of Splited Downloading File 'JkK0a2D  
.`hlw'20  
c-M&cU+=L  
public SiteInfoBean() U(J?Q  
{//nSplitter的缺省值为5 y{v*iH<  
//default value of nSplitter is 5 =#y&xWxL  
this("","","",5); ]}'WNy6c&x  
} EEkO[J[=  
PN\2 ^@>_  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) NugJjd56x  
{ 4pc=MR  
sSiteURL= sURL; *YtITyDS3>  
sFilePath = sPath; 0_&oMPY  
sFileName = sName; `bH Eu"(,  
this.nSplitter = nSpiltter; uQ8
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kkzXv`+  
JVXBm]  
} jkD5Z`D  
+A:}5{  
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public String getSSiteURL() 8eLNKgc  
{ ):.]4n{L  
return sSiteURL; Jwa2Y0  
} g$]9xn#_[  
VF[]E0=u6  
;{Ovqo|  
public void setSSiteURL(String value) BF]b\/I  
{ DtZkrj)D/  
sSiteURL = value; pD &\Z~5
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} 'etCIl3  
xNm<` Y?  
+'lfW{E1t  
public String getSFilePath() hwC3['  
{ ~L}0)FZ\9  
return sFilePath; kM9E)uT>(<  
} vWj|[| <rX  
?[T&y ,ln  
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public void setSFilePath(String value) zL7+HY*3o  
{ | @mZ]`p  
sFilePath = value; ap=M$9L'  
}  =v8#@$  
nE/T)[1|  
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public String getSFileName() E%40u.0  
{ {v2Q7ZO-  
return sFileName; 1;H(   
} K}a[~  
l(<o,Uv[`  
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public void setSFileName(String value) `aSz"4Wd  
{ Ag?@fuk$J  
sFileName = value; y~W6DL}  
} -4V1
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?MN?.O9-  
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public int getNSplitter() &&>OhH`  
{ ~j8x"  
return nSplitter; 3RGVH,  
} Nf3Kz#!B  
cG^'Qm  
0iHK1Pt}  
public void setNSplitter(int nCount) dIK!xOStA  
{ RL
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nSplitter = nCount; M%6{A+(  
} u2BVQ<SA  
} B8C"i%8V)  
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X,gXgxP\  
/* j@ =n|cq  
**Utility.java '2#O{  
*/ am@\$Sa4
 
package NetFox; i1
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#t{?WkO[  
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public class Utility { s%p(_pB  
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public Utility() FK+jfr [  
{ F"9qBl~  
:%;K`w  
S .1~#  
} 2MJ0[9  
J *^|ojX  
//线程睡眠 yyBfLPXZ  
public static void sleep(int nSecond) 18|H  
{ oIf-s[uH  
try{ <5q:mG88  
Thread.sleep(nSecond); X
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} U3p=H^MB.  
catch(Exception e) "iOT14J!7  
{ 6
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e.printStackTrace (); 9 ?h)U|J?G  
} =Y /  
} 3hb1^HNT  
nCYicB  
//日志 ^ zo"~1  
public static void log(String sMsg) $|sRj!F  
{ "-N%`UA  
System.err.println(sMsg); q.rnZU  
} &9TG&~(+  
g$$uf[A-SL  
4Mnne'7  
public static void log(int sMsg) VNA VdP  
{ o6oZk0  
System.err.println(sMsg); Rl$NiY?2  
} ud!iy  
} y%3Yr?]  
[@.%6aD  
qhiQ!fMQ  
/* Gu&zplB  
**TestMethod.java {3`9A
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*/ ")cdY)14"  
package NetFox; +&Sf$t 1  
?%;)> :3N  
m#DC;(Pn  
public class TestMethod { \
6nWt6M  
/sC$;l  
Z]"ktb;+[  
public TestMethod() `2Ff2D^ ?  
{ ///xx/weblogic60b2_win.exe =yvyd0|35  
try{ 2hu;N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); eK4\v:oG1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fWF\V[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Q9?/)&3Bu  
fileFetch.start(); n T\W|  
} [o\O^d  
catch(Exception e){e.printStackTrace ();} Hz*!c#  
1R1J/Z*V/  
&LHQ)?  
} [V}I34UN  
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^tae (}  
public static void main(String[] args) h6la+l?x  
{  cfpP?  
new TestMethod(); jjEkz 5
 
} ;o"}7'4*R%  
} O_(/uLH  
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