http断点续传简单实现（java)

/* ~\SGb_2  
**SiteFileFetch.java yF:1( 4  
*/ yu {d! {6  
package NetFox; @ y.?:7I  
import java.io.*; >{]%F*p4  
import java.net.*; v~+(GqR=+  
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public class SiteFileFetch extends Thread { dbLZc$vPj  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]#<4vl\  
long[] nStartPos; //开始位置 ]EbM9Fo-U  
long[] nEndPos; //结束位置 ^0)g/`H^>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 G't$Qx,IC  
long nFileLength; //文件长度 KkyVSoD\  
boolean bFirst = true; //是否第一次取文件 BZ#(   
boolean bStop = false; //停止标志 Y Uc+0  
File tmpFile; //文件下载的临时信息 pad*oPH,  
DataOutputStream output; //输出到文件的输出流 gaxsv[W>^  
+
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） P:S.~Jq  
public SiteFileFetch(SiteInfoBean bean) throws IOException uc{Ihw  
{ g/_5unI}u  
siteInfoBean = bean; ~At7 +F[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Kn{4;Xk\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3NqB <J  
if(tmpFile.exists ()) XX!%RE`M8  
{ q$UJ$7=f8  
bFirst = false; mIvx1_[  
read_nPos(); "{+QW  
} #MkTkm&r  
else N% B>M7-=  
{ g =hg%gRy"  
nStartPos = new long[bean.getNSplitter()]; Paq4  
nEndPos = new long[bean.getNSplitter()]; 2qN
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} @;4zrzQi7  
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} bj^5yX;2  
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{?0lBfB"  
public void run() 3%|&I:tI  
{ GA)`-*.R  
//获得文件长度 C=xa5Y  
//分割文件 P;no?  
//实例FileSplitterFetch :kV#y  
//启动FileSplitterFetch线程 }#+^{P3;  
//等待子线程返回 }&D WaO]J7  
try{ {WS;dX4  
if(bFirst) uMv,zO5  
{ bWS&Yk(  
nFileLength = getFileSize(); J{<X7uB  
if(nFileLength == -1) CxmKz78  
{ :Ov6_x]*  
System.err.println("File Length is not known!"); ,THw"bm  
} {uFO/  
else if(nFileLength == -2) Qljpx?E  
{ Zl!kJ:0  
System.err.println("File is not access!"); RBd7YWo\|j  
} 8W7J3{d  
else # w4-aJ  
{ Lb-OsKU  
for(int i=0;i<nStartPos.length;i++) >|=ts  
{ H41?/U,{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6_;icpN]  
} MchA{p&Ol  
for(int i=0;i<nEndPos.length-1;i++) {Mk6T1Bkq  
{ A{zN| S[  
nEndPos = nStartPos[i+1]; (mB&m@-N  
} 2pCaX\t  
nEndPos[nEndPos.length-1] = nFileLength; E]d.z6k  
} Ne!lH@ql  
} wQf-sk#  
?j.,Nw4FC  
{YC@T(  
//启动子线程 ]/6z; ~3U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; IPpN@  
for(int i=0;i<nStartPos.length;i++) y.k~Y0  
{ 8Fh)eha9f  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U/M>?G~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), q?:dCFw$x5  
nStartPos,nEndPos,i); N~gzDQ3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ejd(R+  
fileSplitterFetch.start(); /N.b%M]!  
} M_f:A  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6@!`]tSCK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s8Q 5ui]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :-Z2:
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nEndPos = " + nFileLength); WU` rh^  
// fileSplitterFetch[nPos.length-1].start(); cjY-y-vO  
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P+sW[:  
//等待子线程结束 3?yg\  
//int count = 0; @mBQ?;qlK  
//是否结束while循环 Y=KTeYW`  
boolean breakWhile = false; UkC!1Jy  
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.<FH>NW)  
while(!bStop) sP~<*U.7  
{ j$:~Rek  
write_nPos(); +sA2WK]  
Utility.sleep(500); pv&sO~!iC  
breakWhile = true; U)gH}0n&  

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for(int i=0;i<nStartPos.length;i++) 6 "sSoj  
{ B9 uoVcW  
if(!fileSplitterFetch.bDownOver) WH}y"W  
{ {P./==^0  
breakWhile = false; aXYY:;  
break; Y.UFbrv  
} 'H!Uh]!  
} BU_nh+dF  
if(breakWhile) AT3Mlz~7#  
break; tNI^@xdim1  
 8nJpp  
cI*;k.KU  
//count++; p2](_}PK  
//if(count>4) Kc-W&?~y#1  
// siteStop(); LRA8p<Rs  
} n84|{l581  
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4VSU8tK|N]  
System.err.println("文件下载结束！"); Sm|6 %3  
} AkV#J, 3LC  
catch(Exception e){e.printStackTrace ();} eMsd37J  
} CTa57R  
q} >%8;nm  
F4
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//获得文件长度 3 0H?KAV  
public long getFileSize() ,
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{ ?a5!H*,  
int nFileLength = -1; PZ9I`P!C  
try{
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URL url = new URL(siteInfoBean.getSSiteURL()); cwg"c4V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K%oG,-wdg  
httpConnection.setRequestProperty("User-Agent","NetFox"); D,feF9  
?tbrbkx  
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int responseCode=httpConnection.getResponseCode(); :I#V.  
if(responseCode>=400) &QgR*,5eo  
{ SJ,v?=S
!  
processErrorCode(responseCode); }7Q%6&IR  
return -2; //-2 represent access is error 5b*C1HS@X  
} 8ib:FF(= u  
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String sHeader; N6:`/f+A>T  
1+s;FJ2}  
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for(int i=1;;i++) k,*XG$2h  
{ *2l7f`K  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Zy/_ E@C}u  
//Utility.log(in.readLine()); ;=z
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sHeader=httpConnection.getHeaderFieldKey(i); 0=YI@@n)  
if(sHeader!=null) q
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{ hVY$;s  
if(sHeader.equals("Content-Length")) k_#)Tw*  
{ <P_-s*b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); WyiQoN'q  
break; }K(TjZR  
} 9*M,R,y  
} @yYkti;4-  
else F^:3?JA_  
break; t6c4+D'{].  
} N!}f}oF  
} g_bLl)g<  
catch(IOException e){e.printStackTrace ();} ]-#DB^EQ  
catch(Exception e){e.printStackTrace ();} {Sh ;(.u^  
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Utility.log(nFileLength); RRJ%:5&  
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e
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return nFileLength; UN#S;x*  
} TWTb?HP  
f o3}W^0  
;uGv:$([g  
//保存下载信息（文件指针位置） :3 mh@[V  
private void write_nPos() +}AI@+  
{ pb,d'z\S  
try{ 8oGRLYU N  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2 %]X+`+O  
output.writeInt(nStartPos.length); AbM'3Mkz  
for(int i=0;i<nStartPos.length;i++) HoAy_7-5  
{ 2=}FBA,2  
// output.writeLong(nPos); [-w%/D%@  
output.writeLong(fileSplitterFetch.nStartPos); y~V(aih}D  
output.writeLong(fileSplitterFetch.nEndPos); BgT*icd8d  
} ?Bmb' 3  
output.close(); !4!~Lk=  
} ;tf=gdX;  
catch(IOException e){e.printStackTrace ();} DY*N|OnqJ  
catch(Exception e){e.printStackTrace ();} EU#^7  
} %C]>9."  
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//读取保存的下载信息（文件指针位置） l[J8!u2Xp  
private void read_nPos() l]SX@zTb  
{  ='jT~\  
try{ zbiLP83  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K
8O|?x]  
int nCount = input.readInt(); /dHF6yW  
nStartPos = new long[nCount]; /bmN\I  
nEndPos = new long[nCount]; e3\T)x&=  
for(int i=0;i<nStartPos.length;i++) !,PWb3S  
{ j>kqz>3  
nStartPos = input.readLong(); `]aeI'[}R  
nEndPos = input.readLong(); rm_Nn8p,  
} Hn:Crl y#  
input.close(); 7+*WH|Z@  
}  D%Z|  
catch(IOException e){e.printStackTrace ();} W+* V)tf  
catch(Exception e){e.printStackTrace ();} '+ ?X  
} +7}]E1Uf  
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private void processErrorCode(int nErrorCode) HaYo!.(Fv  
{ ;*J  
System.err.println("Error Code : " + nErrorCode); xSu >  
} ,r}6iFu  
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//停止文件下载 qQa}wcU'9p  
public void siteStop() 30{ gI0jk  
{ p ll)Y  
bStop = true; $[|mGae  
for(int i=0;i<nStartPos.length;i++) *1"+%Z^  
fileSplitterFetch.splitterStop(); xz]~ jL@-]  
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} ~J]qP#C  
} qP ,E
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//负责部分文件的抓取 '"Nr,vQo  
**FileSplitterFetch.java gG
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*/ 9BB=YnKE  
package NetFox; HOi`$vX}N  
#&4=VGx{ #  
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import java.io.*; Gm`8q}<I  
import java.net.*; .)3<Q}>  
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public class FileSplitterFetch extends Thread { p<%d2@lp  
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String sURL; //File URL I=#$8l.*  
long nStartPos; //File Snippet Start Position 8EYk
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long nEndPos; //File Snippet End Position ~6gPS 13  
int nThreadID; //Thread's ID n{jGOfc  
boolean bDownOver = false; //Downing is over "  1tH  
boolean bStop = false; //Stop identical >mkFV@`  
FileAccessI fileAccessI = null; //File Access interface p4QU9DF  
s#MPX3itK  
}0 ?3:A  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException iDD$pd,e\  
{ fV~~J2IK  
this.sURL = sURL; _v:SP LU  
this.nStartPos = nStart; `@%LzeGz  
this.nEndPos = nEnd; ` %}RNC  
nThreadID = id; -RLOD\ZBh  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;@
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} [><Tm\(:  
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public void run() d_CT$  
{ MOC/KNb  
while(nStartPos < nEndPos && !bStop) YZ7.1`8  
{ z!\*Y =
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try{ k{0o9,  
URL url = new URL(sURL); sRf
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c",*h  
httpConnection.setRequestProperty("User-Agent","NetFox"); m+9#5a-  
String sProperty = "bytes="+nStartPos+"-"; 0"#HJA44  
httpConnection.setRequestProperty("RANGE",sProperty); .]Z"C&"N]  
Utility.log(sProperty); T{'RV0%   
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InputStream input = httpConnection.getInputStream(); D'4\*4is  
//logResponseHead(httpConnection); ,,T
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byte[] b = new byte[1024]; fy$1YI>!Q  
int nRead; Kpp_|2|@<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) `h;[TtIX4  
{ >sbu<|]a 7  
nStartPos += fileAccessI.write(b,0,nRead); S>{~nOYt-`  
//if(nThreadID == 1) rlD8D|ZG  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V8(-  
} pot~<d`:K"  
ce(#2o&`  
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Utility.log("Thread " + nThreadID + " is over!"); ,?3G;-  
bDownOver = true; )e{}V\;q  
//nPos = fileAccessI.write (b,0,nRead); 8>V5dEbx'  
} 4+i
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catch(Exception e){e.printStackTrace ();} {Ha57Wk8D  
} EK'!}OGCG  
} 2pAW9R#UV-  
^}r1;W?n  
Xr{v~bf  
//打印回应的头信息 s`UJ1eJ  
public void logResponseHead(HttpURLConnection con) _*zt=zn>  
{ vv7I_nK?  
for(int i=1;;i++) KSL`W2}  
{ g .\[o@H  
String header=con.getHeaderFieldKey(i); 1eKT^bgM  
if(header!=null) "5 A!jq  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
f 1d?.)  
Utility.log(header+" : "+con.getHeaderField(header)); bZ6+,J  
else g78^9Y*1  
break; ;G!q Y  
} cZ06Kx..  
} W8<%[-r  
;Xw~D_uv  
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public void splitterStop() DI%saw  
{ r/1(]#kOX  
bStop = true; -HuA \0J  
} x"~JR\yzKJ  
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} P*o9a  
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/* #1[u(<AS  
**FileAccess.java =QsYXK7Mn4  
*//文件访问(定位，写) o}!PQ#`M  
package NetFox; ME dWLFf  
import java.io.*; UI#h&j5pW  
W4N{S.#!  
_Y!IEAU/#  
public class FileAccessI implements Serializable{ y)pk6d  
}M+7T\J!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~m |BC*)  
RandomAccessFile oSavedFile; nrb Ok4Dz  
long nPos; 626r^c=  
rGO8!X 3d  
:-'qC8C  
public FileAccessI() throws IOException 26nx`w?j(  
{ $C\BcKlmv  
this("",0); Q;u pau  
} 7L??ae  
]-q;4.  
#F#%`Rv1  
public FileAccessI(String sName,long nPos) throws IOException nK,w]{<wG!  
{ Ned
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oSavedFile = new RandomAccessFile(sName,"rw"); KSvE~h[#+  
this.nPos = nPos; PeT'^?>  
oSavedFile.seek(nPos); 6 r"<jh#  
} ]oxZ77ciL  
"fI6Cpc  
0mnw{fE8_  
public synchronized int write(byte[] b,int nStart,int nLen) ]! dTG  
{ PdCEUh\>y  
int n = -1; 9my^Y9B  
try{ yw!{MO  
oSavedFile.write(b,nStart,nLen); 2?5>o!C  
n = nLen; q@qsp&0/  
} :0ep(<|;  
catch(IOException e) +H.`MZ=  
{ FtZ?C@1/  
e.printStackTrace (); >bxS3FCX  
} `g,..Ns-r  
NgwbQ7)  
s>en  
return n; H.c7Nle  
} /mMV{[  
:svqE+2  
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} w@pPcZ>z/  
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/* ?`#Khff?  
**SiteInfoBean.java Si7*& dw=  
*/ aYeR{Y]  
package NetFox; JLYi]nZ  
 <Uur^uB  
y(&Ac[foS}  
public class SiteInfoBean { =I4lL]>  
>Q/Dk7#  
VQs5"K"  
private String sSiteURL; //Site's URL C}X\|J  
private String sFilePath; //Saved File's Path #QPjkR|\  
private String sFileName; //Saved File's Name qLCR] _*  
private int nSplitter; //Count of Splited Downloading File N;d] 14|  
u y+pP!<  
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public SiteInfoBean() mR~&)QBP.  
{//nSplitter的缺省值为5 : +u]S2u{  
//default value of nSplitter is 5 &L:!VL{I  
this("","","",5); GVz6-T~\>  
} FlQGgVN  
@c#(.=  
>usL*b0%  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =v\.h=~~  
{ LscGTs,  
sSiteURL= sURL; 5s XXM  
sFilePath = sPath; 5tnlrqC  
sFileName = sName; 83m3OD_y  
this.nSplitter = nSpiltter; ~>G^=0LT  
9^x> 3Bo  
UBs4K*h|  
} QnDg6m)+  
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5xBbrU;  
public String getSSiteURL() =%7-ZH9  
{ Q
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return sSiteURL; [KQi.u  
} Kq!3wb;  
}b}m3i1  
jCY%|  
public void setSSiteURL(String value) x38QD;MT  
{ b$7 +;I;  
sSiteURL = value; IgzQr>  
} 3R/bz0 V>  
'R)Tn!6  
*Ly6`HZ9  
public String getSFilePath() 5(2;|I,T  
{ NlqImM=r,  
return sFilePath; >~f]_puT  
} d5b% W3  
dQvcXl]  
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public void setSFilePath(String value) maZ)cW?  
{ K}y f>'O  
sFilePath = value; yauvXosX  
} LD?sh
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@iiT
<
 
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public String getSFileName() xk5]^yDp  
{ jdN`mosJ  
return sFileName; YUb_y^B^  
} RCrCs  
;a/E42eN;  
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public void setSFileName(String value) qK+5NF|  
{ Sdo-nt  
sFileName = value; Ef\-VKh  
} hPh-+Hb  
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/FII07V  
public int getNSplitter() :s,Z<^5a)g  
{ ~u{uZ(~
  
return nSplitter; SM'|+ d  
} t
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e.>P8C<&  
public void setNSplitter(int nCount) GyIV Hby  
{ #cJ@uqR  
nSplitter = nCount; O1lNAcpeM  
} _!6jR5&r,  
} f3;5Am  
>?b!QU*a  
M:8R-c#![  
/* `uFdwO'DD  
**Utility.java {ax:RUQxy  
*/ /z!%d%"  
package NetFox; }C:r9?T  
\zY!qpX<  
w xH7?tsf  
public class Utility { 45e~6",  
sB</DS  
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public Utility() Y73C5.dNcE  
{ :h$$J lP  
_w{Qtj~s|  
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} $`c:&  
9Na$W:P c  
//线程睡眠 @FeTz[  
public static void sleep(int nSecond) osRy e3  
{ 2T35{Q!=F  
try{ eavV?\uV%  
Thread.sleep(nSecond); 1^}+=~  
} g(052]  
catch(Exception e) hrn+UL:d  
{ P?\6@_ Z  
e.printStackTrace (); &&+H+{_Q  
} ]'}L 1r  
} )UR7i8]!0  
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//日志 zdYjF|  
public static void log(String sMsg) \<' ?8ri#  
{ L#J1b!D&<6  
System.err.println(sMsg); fl(wV.Je|  
} t!Xw
W$@  
vt8By@]:  
]`K2N  
public static void log(int sMsg) `Oa WGZ[  
{ ~a:  
System.err.println(sMsg); vQCy\Gi  
} }j%5t ~Qa  
} \85i+q:LuA  
gJXaPJA{  
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/* V&5wRz+`W  
**TestMethod.java yA
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*/ WJ#[LF!e  
package NetFox; \e;iT\=.(  
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public class TestMethod { DUS6SO  
!zo{tI19  
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public TestMethod() ]esC[r]PJ  
{ ///xx/weblogic60b2_win.exe ^sw?gH*  
try{ RP"kC4~1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); aOp\91  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U/U
);frH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &8H'eAA  
fileFetch.start(); b=vkiO`2  
} _XBd3JN@
 
catch(Exception e){e.printStackTrace ();} C]6O!Pb0  
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} L,\Iasv  
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public static void main(String[] args) ^!d3=}:
0  
{ iTwm3V P  
new TestMethod(); ;pAK_>
 
} >7|VR:U?B  
} Ac@VGT:9  
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