http断点续传简单实现（java)

/* a?h*eAAc.  
**SiteFileFetch.java Gbpw5n;e  
*/ 26?W nu60  
package NetFox; K>:]Bx#F7  
import java.io.*; aW_oD[l  
import java.net.*; d~J-|yyT  
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public class SiteFileFetch extends Thread { uP $Cj  
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SiteInfoBean siteInfoBean = null; //文件信息Bean oTjyN\?H  
long[] nStartPos; //开始位置 G6P)C##ibn  
long[] nEndPos; //结束位置 m0w;8uF2UV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 eDI=nSo  
long nFileLength; //文件长度 7R.Q Ql  
boolean bFirst = true; //是否第一次取文件 +gd2|`#  
boolean bStop = false; //停止标志 PC$CYW5  
File tmpFile; //文件下载的临时信息 Vgb *% I  
DataOutputStream output; //输出到文件的输出流 lA(Q@yEW  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %VJ85^B3  
public SiteFileFetch(SiteInfoBean bean) throws IOException p^kUs0$GS  
{ P;[OWSR[d  
siteInfoBean = bean; ^$>XW\yCs  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &GTI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n%^ LPD  
if(tmpFile.exists ()) Z7rJ}VP  
{ #m{{a]zm^  
bFirst = false; =WdaxjenZ/  
read_nPos(); RgdysyB  
} vr^~yEr  
else -~[9U,  
{ Lf([dE1  
nStartPos = new long[bean.getNSplitter()]; )5j;KI%t  
nEndPos = new long[bean.getNSplitter()]; 3ya1'qUC  
} b !@Sn/  
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} `(+o=HsD  
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public void run() >SN|?|2U/  
{ cfox7FmW  
//获得文件长度 "'8KV\/D  
//分割文件 s]T""-He  
//实例FileSplitterFetch zf4Ec-)  
//启动FileSplitterFetch线程 KfBTL!0#  
//等待子线程返回 &1l=X]%  
try{ ]q-g[e'  
if(bFirst) .6O"| Mqb  
{ 9!9Z~/*m  
nFileLength = getFileSize(); A7!g  
if(nFileLength == -1) MS(JR  
{ >e2<!#er|  
System.err.println("File Length is not known!"); EM7+VO(  
} ccCzu6  
else if(nFileLength == -2) {GvTfZfp  
{ Am8x74?  
System.err.println("File is not access!"); +,:du*C  
} 4`Q3v4fOF  
else O\K_q7iO6  
{ oLWJm  
for(int i=0;i<nStartPos.length;i++) e*(b  
{ Lb{e,JH  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); KZ!3j_pKy  
} $F.([?)k?  
for(int i=0;i<nEndPos.length-1;i++) 1Z[/KJ  
{ *Nyev]8  
nEndPos = nStartPos[i+1]; K =.%$A  
} #`GY}-hL!  
nEndPos[nEndPos.length-1] = nFileLength; j1SMeDDM ~  
} hYQ_45Z*?  
} th6+
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//启动子线程  tvXW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #jAqra._b  
for(int i=0;i<nStartPos.length;i++) x^"ES%*  
{ IHgeQ F ~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kc/{[ME  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), b{fQ|QD{^E  
nStartPos,nEndPos,i); |F.)zC5{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =%zLh<3v  
fileSplitterFetch.start(); X2tk[Kr  
} {;2vmx9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &V|>dLT>A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9%*wb`&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )BfT7{WN  
nEndPos = " + nFileLength); #W.vX?-'0  
// fileSplitterFetch[nPos.length-1].start(); tBTTCwNT%  
+0),xu   
lpH=2l$>?  
//等待子线程结束 x8
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//int count = 0; 9N%JP+<89  
//是否结束while循环 0Z|FZGRP  
boolean breakWhile = false; ExHKw~y9  
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while(!bStop) .1 %T W)  
{ RE.r4uOJg  
write_nPos(); X7L8h'(@  
Utility.sleep(500); B3Jgd,[  
breakWhile = true; 3]-_q"Co4f  
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for(int i=0;i<nStartPos.length;i++) jL
)WPq!m+  
{ &R~n>>c  
if(!fileSplitterFetch.bDownOver) O4<g%.HC6  
{ iqnJ~g  
breakWhile = false; (;. AS  
break; 'WHHc 9rG,  
} B*htN  
} Ifk
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if(breakWhile) ::n;VY2&  
break; !L5jj#0  
-/]W+[  
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//count++; J8y0d1SG  
//if(count>4) &h*S y  
// siteStop(); OL7_'2_z.  
} 5 ,0d  
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*/ G<!W  
System.err.println("文件下载结束！"); sBv>E}*R  
} TwyM\9l7  
catch(Exception e){e.printStackTrace ();} D71;&G]0  
} Qr#1u  
Z -%(~  
2!N8rHRt  
//获得文件长度 R~bC,`Bh  
public long getFileSize() BF{w)=@/'  
{ y{q*s8NY  
int nFileLength = -1; 1exl0]-  
try{ iAY!oZR(WT  
URL url = new URL(siteInfoBean.getSSiteURL()); hzI*{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .s/fhk,  
httpConnection.setRequestProperty("User-Agent","NetFox"); W:i?t8y\y  
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int responseCode=httpConnection.getResponseCode(); ~.PP30'  
if(responseCode>=400) dBO@6*N4c  
{ c= UU"  
processErrorCode(responseCode); F>]#}_  
return -2; //-2 represent access is error F#xa`*AP  
} 5>9Y|UU  
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String sHeader; 4!`bZ`_Bw  
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s!/TU{8J  
for(int i=1;;i++) 4 ;Qlu  
{ r%Rs0)$yj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); XwM611  
//Utility.log(in.readLine()); S
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sHeader=httpConnection.getHeaderFieldKey(i); HEK-L)S. *  
if(sHeader!=null) !BU)K'mj  
{ 3*DXE9gA9  
if(sHeader.equals("Content-Length")) \^*< y-jL  
{ x4Rk<Th"o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &O[s:  
break; 4^c-D  
} E04l|  
} OH<?DcfeL  
else tXF]t   
break; yh;Y,;4  
} $ &5w\P  
} 6FfOH<\z6i  
catch(IOException e){e.printStackTrace ();} 8F;>5i  
catch(Exception e){e.printStackTrace ();} \d.F82  
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Utility.log(nFileLength); jm>3bd  
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return nFileLength; )"@t6.  
} &!7+Yb(1  
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s #:%x#  
//保存下载信息（文件指针位置） A3P9.mur  
private void write_nPos() \hk/1/siyF  
{ 1`r| op},  
try{ E|Bd>G  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?s} %  
output.writeInt(nStartPos.length); p|6v~  
for(int i=0;i<nStartPos.length;i++) cErI%v}v0  
{ aP
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// output.writeLong(nPos); Rc
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output.writeLong(fileSplitterFetch.nStartPos); 7-iIay1h"  
output.writeLong(fileSplitterFetch.nEndPos); ka7uK][  
} +
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output.close(); 2@@l{Y0f6  
} fhpX/WE6  
catch(IOException e){e.printStackTrace ();} [p;*r)f2}
 
catch(Exception e){e.printStackTrace ();} tR
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} U
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//读取保存的下载信息（文件指针位置） =v2%Vs\7k  
private void read_nPos() ^^LjI  
{ %&] 1Fh
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try{ ?#[)C=p]z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jPwef##~7  
int nCount = input.readInt(); lSCY5[?  
nStartPos = new long[nCount]; 'C]jwxy  
nEndPos = new long[nCount]; _ VKgs]Y  
for(int i=0;i<nStartPos.length;i++) zGs|DB  
{ : ^(nj7D  
nStartPos = input.readLong(); kyAs'R@z  
nEndPos = input.readLong(); "Pdvmur  
} u~Lu<3v  
input.close(); Y?!/>q  
} ;/A}}B]y  
catch(IOException e){e.printStackTrace ();} Fzs>J&sY&  
catch(Exception e){e.printStackTrace ();} 9".Uc8^p/F  
} D0M!"c>\  
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private void processErrorCode(int nErrorCode) XARSGAuw  
{ HWbBChDF  
System.err.println("Error Code : " + nErrorCode); |0w~P s  
} # ITLz!gE  
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//停止文件下载 oP-;y&AS  
public void siteStop() {d}26 $<$]  
{ <j"O%y.  
bStop = true; /$*; >4=>f  
for(int i=0;i<nStartPos.length;i++) /'`6 ; uRN  
fileSplitterFetch.splitterStop(); 0# UAjT3  
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} ;_bq9x  
} z (#Xca  
//负责部分文件的抓取 Sgx+V"bkT  
**FileSplitterFetch.java Fj3^ #ly  
*/ g\j>qUjs%Q  
package NetFox; 6m\*]nOy4  
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import java.io.*; _X?y,#  
import java.net.*; * S{\#s  
*|CLO|B)  
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public class FileSplitterFetch extends Thread { F]P
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String sURL; //File URL |'@V<^GR  
long nStartPos; //File Snippet Start Position .yG8B:7N2  
long nEndPos; //File Snippet End Position >]C<j4
 
int nThreadID; //Thread's ID }o{!}g9  
boolean bDownOver = false; //Downing is over z.{HD9TD  
boolean bStop = false; //Stop identical P$F#,Cn  
FileAccessI fileAccessI = null; //File Access interface xz="|HD);  
Hc"N& %X[  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =^ gvZ|]  
{ @eA %(C  
this.sURL = sURL; *SXSF95  
this.nStartPos = nStart; vr<)Ay  
this.nEndPos = nEnd; 0.3^  
nThreadID = id; ;q'DGzh  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !+%Az*ik  
} +i2YX7Of  
+6wx58.B&  
ho(5r5SNE  
public void run() r
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{ |:\$n}K  
while(nStartPos < nEndPos && !bStop) aKaR  
{ vRq=m8  
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try{ !7ph,/P$7  
URL url = new URL(sURL); HIQ]"Hl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \IO$+Guh  
httpConnection.setRequestProperty("User-Agent","NetFox"); t*5z1T?  
String sProperty = "bytes="+nStartPos+"-"; jM{(8aUG  
httpConnection.setRequestProperty("RANGE",sProperty); $(Z]TS$M&  
Utility.log(sProperty); [BJ$|[11  
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+"TI_tK,S  
InputStream input = httpConnection.getInputStream(); Q@ykQ  
//logResponseHead(httpConnection); .G7]&5s  
Tyg$`\#   
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byte[] b = new byte[1024]; +e&m#d  
int nRead; *1 n;p)K  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :|*Gnu  
{ l{M;PaJ`}  
nStartPos += fileAccessI.write(b,0,nRead); OHx,*
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//if(nThreadID == 1) pil0,r $D  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *#ob5TBq[  
} !C9ps]6
 
!N@S^JD6  
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Utility.log("Thread " + nThreadID + " is over!"); oi33{#%t  
bDownOver = true; uW\@x4  
//nPos = fileAccessI.write (b,0,nRead); EqNz L*E  
} c4!c_a2pS  
catch(Exception e){e.printStackTrace ();} tdMP,0u  
} v#F
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} B,BOzpb(  
!mpMa]G3  
> {'5>6u  
//打印回应的头信息 =8$(i[;6w  
public void logResponseHead(HttpURLConnection con) Z`SWZ<  
{ F]URf&U  
for(int i=1;;i++) X]3l| D  
{ twYB=68  
String header=con.getHeaderFieldKey(i); tu?Z@W/  
if(header!=null) "/ a*[_sV  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Lic{'w&  
Utility.log(header+" : "+con.getHeaderField(header)); 8|S1|t,  
else
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break; !%Z)eO~Z  
} hB2s$QS  
} LP0;n\  
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public void splitterStop() p ?Ij-uo"o  
{ OTNZ!U/)j  
bStop = true; d @^o/w8  
} I9Edw]  
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} &8:iB {n  
T
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/* j"D0nG,  
**FileAccess.java fRv S@  
*//文件访问(定位，写) @y;tk$e  
package NetFox; =@ 
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import java.io.*; ,,wyydG  
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n{qw]/  
public class FileAccessI implements Serializable{ "$,}|T?Y`  

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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 tx|"v|&e2  
RandomAccessFile oSavedFile; "oj
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long nPos; J7
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public FileAccessI() throws IOException 79c9+  
{ x`=5l`  
this("",0); u{E^<fW]  
} b3 %&   
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z*k3q`=>  
public FileAccessI(String sName,long nPos) throws IOException #`6OC)1J  
{ -SC2Zgi)A  
oSavedFile = new RandomAccessFile(sName,"rw"); hF=V
?\  
this.nPos = nPos; b$`4Nn|  
oSavedFile.seek(nPos); 4~pO>6P   
} w4<u@L  
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public synchronized int write(byte[] b,int nStart,int nLen) !i"9f_  
{ m?R+Z6c[  
int n = -1; b09#+CH?  
try{ K~hlwjrt  
oSavedFile.write(b,nStart,nLen); H@&"M%  
n = nLen; I`n1M+=%  
} gQ+_&'C  
catch(IOException e) /wCxf5q0  
{ 3bI|X!j  
e.printStackTrace (); raI~BIfe  
} <
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0 *Yivx6  
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return n; cX=b q_  
} ?$8 ,j+&I  
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} ])ZJ1QL1  
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/* Hd@T8 D*A  
**SiteInfoBean.java k3|9U'r!c  
*/ ,vY I O  
package NetFox; qaSv]k.  
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Pc:'>,3!V3  
public class SiteInfoBean { ljR?* P  
vR.6^q  
1~ZHC[ `  
private String sSiteURL; //Site's URL >a] s  
private String sFilePath; //Saved File's Path k}a!lI:  
private String sFileName; //Saved File's Name 0BwQ!B.  
private int nSplitter; //Count of Splited Downloading File Zo6a_`)d  
"kuBjj2  
b:
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public SiteInfoBean() l[j0(T  
{//nSplitter的缺省值为5 R8Ei:f}  
//default value of nSplitter is 5 cngPc]?N  
this("","","",5); r3lr`s`  
}
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a+Qj[pS  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !{=%l+^.  
{ ON=ley  
sSiteURL= sURL; sN/Xofh  
sFilePath = sPath; =|zyi|  
sFileName = sName; HDG"a&$   
this.nSplitter = nSpiltter; 8{^GC(W{]  
7.'j~hJL  
Z"&ODVP  
} ~bQ:gArk  
@?NLME  
0 #; s{7k  
public String getSSiteURL() .:Xe*Q  
{ jtCob'n8  
return sSiteURL; jS)-COk  
} 2MrR|hLx  
-BH'.9uqGQ  
3gXUfv2ID  
public void setSSiteURL(String value) ag4^y&  
{ 3]82gZGG  
sSiteURL = value; dKG<"
 
} ({62GWnn_  
T>?1+mruM  
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public String getSFilePath() oO,p.X%  
{ K_Gf\x  
return sFilePath; E 4(muhY  
} l1j   
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e q.aN3KB"  
public void setSFilePath(String value) P=i |{vv(  
{ G4]``  
sFilePath = value; >@\-m  
} SQRz8,sqkw  
1%{(?uz9  
!S<~(Ujyw  
public String getSFileName() cA^7}}?e  
{ z#!Cg*K(  
return sFileName; lKSI5d  
} e6/} M3B  
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public void setSFileName(String value) vdM\scO:  
{ j|w+=A1  
sFileName = value; A).AAr  
} Gj0NN:  
2Ki/K(  
q3:' 69  
public int getNSplitter() sRG3`>1  
{ ;W"[,#2TM  
return nSplitter; IT"jtV  
} @5ybBh]   
[O'p&j@  
Melc-[  
public void setNSplitter(int nCount) we?#)9Q<  
{ Uh}yHD`K  
nSplitter = nCount; %;gWl1&5  
} YEj U3^@  
} >skS`/6  
)<&QcO_  
AEJm/8,T  
/* 5sUnEHN  
**Utility.java bL%)k61G_v  
*/ }2{#=Elh  
package NetFox; c`Cn9bX  
bf+2c6_BN0  
V-|}.kOH2  
public class Utility { ,%^0 4sl  
%Z|*!A+wN5  
x(~
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public Utility() }#M|3h;q9+  
{ R&A.F+Zgt  
Z5K,y19/~  
vYkoh/(/u  
} r+crE %-  
.nJGxz+X"  
//线程睡眠 d0d2QRX  
public static void sleep(int nSecond) <o O_wS@:  
{ FS0SGBo  
try{ rjzRH  
Thread.sleep(nSecond); *np|PyLP:  
} :KwYuwYS  
catch(Exception e) >E#4mm  
{ Wj0([n  
e.printStackTrace (); l0f6Lxfz  
} XR(kR{yo  
} h";sQ'u
s  
191)JWfa  
//日志 _'Z@ < ,L  
public static void log(String sMsg) S6uBk"V!  
{ 4T"P#)z  
System.err.println(sMsg); x.I-z@
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} Wk?XlCj  
A'T! og|5  
Sk xaSJ"  
public static void log(int sMsg) FK>rc3 q  
{ d?JVB  
System.err.println(sMsg); OLq/OO,w  
} 8oK30?  
} '"6VfF)*  
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/* ouujd~b+  
**TestMethod.java ^(y4]yZ  
*/ ]M.ufbguq  
package NetFox; zPn8>J<.0Q  
};
|'8'5  
^(%>U!<<%,  
public class TestMethod { (q utgnW  
z[B7k%}  
-<.>jX  
public TestMethod() !HFwQGP.Y  
{ ///xx/weblogic60b2_win.exe =
d9%ce  
try{ x9a0J1Nb-h  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); fYpy5vc-dm  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); umc!KOkL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @E1N9S?>  
fileFetch.start(); g\2Y605DM  
} ,ua]h8  
catch(Exception e){e.printStackTrace ();} Zu!3RN[lp?  
U^.$k-|k  
ZC05^  
} nRvV+F0#  
27)$;1MT:  
#+XKfumLk  
public static void main(String[] args) ],#9L   
{ {aU~[5L3(  
new TestMethod(); 3?C$Tl2G8  
} 'kp:yI7w  
} <w[)T`4N  
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