http断点续传简单实现（java)

/* {~XnmBs  
**SiteFileFetch.java Fj"/jdM  
*/ !mUO/6Q hq  
package NetFox; 4AKPS&k;  
import java.io.*; <@Y`RqV+  
import java.net.*; t~8H~%T>v  
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+ 7wMM#z  
public class SiteFileFetch extends Thread { o3h>)4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Sar1NkD#  
long[] nStartPos; //开始位置 .=9d3uWJ/  
long[] nEndPos; //结束位置 4`")aM
 
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S,vdd7Y  
long nFileLength; //文件长度 rCb#E}  
boolean bFirst = true; //是否第一次取文件 (D{J|  
boolean bStop = false; //停止标志 z:u)@>6D1  
File tmpFile; //文件下载的临时信息 bc>&Qj2Z7c  
DataOutputStream output; //输出到文件的输出流 xT!<x({  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -x|!?u5F  
public SiteFileFetch(SiteInfoBean bean) throws IOException V~do6[(  
{ tjx|;m7  
siteInfoBean = bean; ZEvK
 
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )g KC}_h=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )RQQhB  
if(tmpFile.exists ()) >B;KpO"+m  
{ ]kF1~kXBe  
bFirst = false; +
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read_nPos(); zU_dk'&,  
} %OP|%^2  
else Fqh./@o  
{ M0`1o p1  
nStartPos = new long[bean.getNSplitter()]; p8Z;QH*  
nEndPos = new long[bean.getNSplitter()]; #L57d  
} &2I8!Ia  
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} :39arq  
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public void run() U}
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{ s_e*jM1  
//获得文件长度 '%o^#gJp  
//分割文件 [8%q@6[  
//实例FileSplitterFetch ,LDL%<7t  
//启动FileSplitterFetch线程 @Bn4ZFB@  
//等待子线程返回 m;L3c(r.  
try{ k;)mc+ ~+  
if(bFirst) w^,Xa  
{ Mc$rsqDz  
nFileLength = getFileSize(); aIh} j,  
if(nFileLength == -1) QS1lg  
{ ($W%&(:/  
System.err.println("File Length is not known!"); zS h9`F  
} |nGv:= H@
 
else if(nFileLength == -2) O,S>6o)?  
{ -)R =p"-w  
System.err.println("File is not access!"); $xcZ{C  
} ;' H\s  
else s)KlKh  
{ 4t3>`x 7  
for(int i=0;i<nStartPos.length;i++) ^YB2E*  
{ JAT%s %UC  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @AK&R~<  
} 7PBE(d%m  
for(int i=0;i<nEndPos.length-1;i++) ~$hR:I1  
{ 0j8`M"6  
nEndPos = nStartPos[i+1]; 2 )3oX  
} ,t:P  
nEndPos[nEndPos.length-1] = nFileLength; %~,Fe7#p  
} Wu(^k25  
} AWssDbh/[  
8=zREt<Se  
oX
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//启动子线程 ]>%2,+5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &0fV;%N  
for(int i=0;i<nStartPos.length;i++) #z7yoP  
{ #M5d,%?+#[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @u:`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), B<n[yiJ}  
nStartPos,nEndPos,i); 7S=,#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dDD5OnWmJ  
fileSplitterFetch.start(); Mc!LC .8  
} (U_HX2f  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VJ_fA}U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .rnT'""i<5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", rBy0hGx  
nEndPos = " + nFileLength); UB
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// fileSplitterFetch[nPos.length-1].start(); c;06>1=wP5  
{J,4g:4G  
6a_U[-a9;  
//等待子线程结束 a'.7)f[g}  
//int count = 0; \u))1zRd  
//是否结束while循环 &\b(  
boolean breakWhile = false; ;jN1n xF  
=1'WZp}D5  
bf{_U%`  
while(!bStop) ,np|KoG|M  
{ ]qu6/Z  
write_nPos(); Fw t  
Utility.sleep(500); $)BPtGMGo  
breakWhile = true; lyyf&?2  
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for(int i=0;i<nStartPos.length;i++) "?lz[K>  
{ GIn%yB'  
if(!fileSplitterFetch.bDownOver) {2q0Ko<  
{ u0G tzk  
breakWhile = false; `%"x'B`mM  
break; x'..j5  
} %Lb
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} \NEk B&^n  
if(breakWhile) l&:8 'k+%=  
break; B& R?{y*  
;[[6[i  
-Fu,oEj{*  
//count++; |5X59! JL  
//if(count>4) xXa4t4gR  
// siteStop(); z;Fz3s7  
} AE~@F4MK  
C=v+e%)x@  
DS>&|zF5l  
System.err.println("文件下载结束！"); 9!Jt}n?!g  
} @!
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catch(Exception e){e.printStackTrace ();} |@yYM-;6  
}  ;Q4,I[?%  
=&qH%S
6  
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//获得文件长度 5??}9  
public long getFileSize() yWE\)]9  
{ D .LR-Z  
int nFileLength = -1; [@8po-()L  
try{ kWy@wPqms  
URL url = new URL(siteInfoBean.getSSiteURL()); MPy><J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `Syfl^9B  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4z26a  
a?8)47)  
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int responseCode=httpConnection.getResponseCode(); .XiO92d9  
if(responseCode>=400) %7w8M{I R3  
{ vw(ecs^C  
processErrorCode(responseCode); 0Q?%B6g$m[  
return -2; //-2 represent access is error *" C9F/R  
} M0\gp@Fe  
?!/8~'xA6  
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String sHeader; _)!*,\*`{  
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for(int i=1;;i++) " zD9R4\X.  
{ 0GeL">v,:=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \AA9 m'BZ  
//Utility.log(in.readLine()); A#19&}  
sHeader=httpConnection.getHeaderFieldKey(i); Dm8fcD  
if(sHeader!=null) ->.9[|lIg  
{ ",Vx.LV  
if(sHeader.equals("Content-Length")) _KxR~
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{ EG$-D@o\I  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (_>SuQK  
break; >/Q^.hzd  
} Kg"eS`-  
} c$L1aZo  
else :yJ([  
break; cfa1"u""e  
} B@0#*I Rm  
} yRl  
catch(IOException e){e.printStackTrace ();} Bp5ra9*5+~  
catch(Exception e){e.printStackTrace ();} U`HY eJ  
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Utility.log(nFileLength); Ba|}$jo  
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return nFileLength; ~ss6yQ$  
} US"g>WLwJ  
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w5~j|c=_W  
//保存下载信息（文件指针位置） -l[$+Kw1S  
private void write_nPos() "-dA\,G  
{ q>>1?hzA  
try{ ~yw]<{?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~LV]cX2J(  
output.writeInt(nStartPos.length); 2ww H3}  
for(int i=0;i<nStartPos.length;i++) ryh"/lu[B  
{ ss-6b^  
// output.writeLong(nPos); eA-oqolY  
output.writeLong(fileSplitterFetch.nStartPos); X#JUorGp  
output.writeLong(fileSplitterFetch.nEndPos); oQu>Qr{Zp  
} lN,a+S/'  
output.close(); \y(3b#  
} 7(h@5  
catch(IOException e){e.printStackTrace ();} $ B&ZnZ?  
catch(Exception e){e.printStackTrace ();} EA8plQ~GtE  
} g)r{LxT#+  
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//读取保存的下载信息（文件指针位置） LPu*Lkx  
private void read_nPos() K[OOI~"C  
{ M|%bxG^l  
try{ nQ+5jGP1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); FjtS  
int nCount = input.readInt(); jaKW[@<  
nStartPos = new long[nCount]; x< 2]UB`  
nEndPos = new long[nCount]; R<6y7?]bZ  
for(int i=0;i<nStartPos.length;i++) 4OgH+<G  
{ yF.Gz`yi  
nStartPos = input.readLong(); gH'hA'  
nEndPos = input.readLong(); jI*@&3  
} 3x+=7Mg9  
input.close(); 2sk7E'2(  
} 7_l Wr  
catch(IOException e){e.printStackTrace ();} uyB2   
catch(Exception e){e.printStackTrace ();} TaHcvjhR  
} _
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private void processErrorCode(int nErrorCode) IjRUr\l  
{ WH1" HO  
System.err.println("Error Code : " + nErrorCode); C5I7\9F)  
} uK"FopUJ4i  
,&S0/j  
`VO;\s$5j  
//停止文件下载 ``VE<:2+  
public void siteStop() i.)n#@M2  
{ !<=zFy[J.9  
bStop = true; n(eo_.W2|  
for(int i=0;i<nStartPos.length;i++) 5!qf{4j  
fileSplitterFetch.splitterStop(); *p\Zc*N;%  
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} XL.f`N.O  
} <iU@ M31  
//负责部分文件的抓取 np6G~0Y`  
**FileSplitterFetch.java 0,DrVGa  
*/ ^IuhHP  
package NetFox; {fHor  
!s1<)%Jt  
_!DH/?aU  
import java.io.*; r/ g{j  
import java.net.*; jF}kV%E  
l~
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*(q?O_3,b  
public class FileSplitterFetch extends Thread { SF-"3M  
U{oM*[  
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String sURL; //File URL f7Nmvla[q  
long nStartPos; //File Snippet Start Position Ul]7IUzsu  
long nEndPos; //File Snippet End Position e8xq`:4Y
 
int nThreadID; //Thread's ID [[AO6.Z  
boolean bDownOver = false; //Downing is over 6#CswSpS  
boolean bStop = false; //Stop identical #vyf*jPr  
FileAccessI fileAccessI = null; //File Access interface ]9/A=p?J@  
}l$zZ>.\H  
L f"!:]  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A"b31*_  
{ qQ3Q4R\  
this.sURL = sURL; z!bT^_Cc0  
this.nStartPos = nStart; ,v8e7T  
this.nEndPos = nEnd; SIrNZ^I  
nThreadID = id; 16 `M=R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h>GbJ/^  
} T{+a48,;  
~<VxtcEBz  
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public void run() -`\rDPGf  
{ |*g#7YL  
while(nStartPos < nEndPos && !bStop) vMou`[\WlJ  
{ U;
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t}h(j|  
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try{ Ev
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URL url = new URL(sURL); QH(&Cu,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~s Hd
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httpConnection.setRequestProperty("User-Agent","NetFox"); ky[Cx!81C  
String sProperty = "bytes="+nStartPos+"-"; oOI0q_bf  
httpConnection.setRequestProperty("RANGE",sProperty); L QV@]z&  
Utility.log(sProperty); ,(x`zpp _  
}>BNdm"Er  
$#D#ezvxe  
InputStream input = httpConnection.getInputStream(); TU~y;:OJ  
//logResponseHead(httpConnection); q5e(~@(z<`  
ff.k1%wr^  
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byte[] b = new byte[1024]; =Vs?=|r  
int nRead; n8;L_43U  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,%IP27bPW  
{ dR\yRC]I  
nStartPos += fileAccessI.write(b,0,nRead); g{}<ptx]  
//if(nThreadID == 1) iEtR<R>=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^z)De+,!4  
} v\?J=|S+  
uVU)LOx  
7MrHu2rZ=  
Utility.log("Thread " + nThreadID + " is over!"); RNB&!NC  
bDownOver = true; }9\6!GY0  
//nPos = fileAccessI.write (b,0,nRead); nN<,rN{:  
} IWq\M,P  
catch(Exception e){e.printStackTrace ();} =h-EN_[  
} \D z? h  
} !% W5@tN  
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K(upzn*a  
//打印回应的头信息 06AgY0\  
public void logResponseHead(HttpURLConnection con) gw,K*ph}q  
{ vf.MSk?~ar  
for(int i=1;;i++) 7"'PfP4c  
{ Posz|u<x  
String header=con.getHeaderFieldKey(i); i3|xdYe$  
if(header!=null) 8/)\nV$0
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); '1b8>L  
Utility.log(header+" : "+con.getHeaderField(header)); Bcv{Y\x;ko  
else W>w(|3\  
break; oA-,>:}g{  
} iKPgiL~  
} |-S!)iG1V  
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public void splitterStop() 5<PNl~0  
{ qtAt=` s  
bStop = true; --l UEo~  
} ^rq\kf*]  
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} AeEdqX)  
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2=K|kp5  
/* sHBTB6)lx  
**FileAccess.java d]sqj\Q57  
*//文件访问(定位，写) nm<VcCc  
package NetFox; HJg&fkHn1  
import java.io.*; |^5"-3Q  
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public class FileAccessI implements Serializable{ qQ)1+^  
s&VsK#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7/hn%obC  
RandomAccessFile oSavedFile; YL|)`m0-^5  
long nPos; n5"oXpcIx  
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public FileAccessI() throws IOException $k&v juB.  
{ -DHzBq=H  
this("",0); Ow>u!P!  
} Gf#l ^yr  
di
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pEcYfj3M  
public FileAccessI(String sName,long nPos) throws IOException 2C:u)}R7D  
{ 7:LEf"vRZ  
oSavedFile = new RandomAccessFile(sName,"rw"); xP>cQELot  
this.nPos = nPos; l9|K,YVW  
oSavedFile.seek(nPos); zT)cg$8%fY  
} H
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;Z0&sFm  
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public synchronized int write(byte[] b,int nStart,int nLen) XTX/vbge3m  
{ y{3+Un  
int n = -1; 5%9Uh'y#  
try{ Go c*ugR  
oSavedFile.write(b,nStart,nLen); uZL,%pF3A  
n = nLen; K!9K^h  
} /77cjesZ9  
catch(IOException e) dO2?&f  
{ <S7SH-{_\  
e.printStackTrace (); ly34aD/p~,  
} -7w}+iS  
bl>W
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return n; E-Xz  
} *V:U\
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t  
} "Ua-7Q&A  
/dg?6XT/  
Rkk`+0K7$J  
/* \PT!mbB?  
**SiteInfoBean.java hY{4_ie=8  
*/ YC 4c-M  
package NetFox; )!rD&l$tE  
?/MkH0[G=  
LvS5N)[  
public class SiteInfoBean { Ws3z-U>j  
Ww8U{f  
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private String sSiteURL; //Site's URL jEQ_#KKYJ  
private String sFilePath; //Saved File's Path wxK71OH  
private String sFileName; //Saved File's Name W^^0Rh_  
private int nSplitter; //Count of Splited Downloading File g,WTXRy  
X1P1 $RdkR  
4.,|vtp  
public SiteInfoBean() l]&A5tz3  
{//nSplitter的缺省值为5 *jc >?)k  
//default value of nSplitter is 5 ,2Ed^!`  
this("","","",5); 6<\dQ+~  
} rMJ@oc  
|Tmug X7  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) rz|Sjtq  
{ }*9F`=%F  
sSiteURL= sURL; PtUS7[]  
sFilePath = sPath;
~
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sFileName = sName; t1iz5%`p}  
this.nSplitter = nSpiltter; 1&e8vVN  
]!S#[Wt {k  
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} ^pe/~ :a  
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public String getSSiteURL() : ^}!"4{  
{ Y{e,I-"{  
return sSiteURL; -tWxBGSa@  
} :I";&7C  
mp sX4  
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public void setSSiteURL(String value) L=Aj+  
{ r*mYtS  
sSiteURL = value; 4IW90"uc  
} 7lF;(l^Z>}  
qOpwl*?x+  
3`SH-"{j%  
public String getSFilePath() %jj-\Gz!  
{ W^[QEmyn  
return sFilePath; !p\ @1?  
} +K'YVB U}  
(L4C1h_]9  
?$A)lWk(  
public void setSFilePath(String value) S`
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{ n=d#Fm0<  
sFilePath = value; d<ES  
} x%$6l  
=HMCNl  
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public String getSFileName() +7WpJ;C4  
{ p[WlcbBwT  
return sFileName; ZI$P Qz2i  
} ^oC>,%7  
qrOesSdc  
9b-4BON{P  
public void setSFileName(String value) %<Qv?`B  
{ @fo(#i&  
sFileName = value; wb#[&2
i  
} py~[M'p(H  
{
be|G^.c  
A`vRUl,c=  
public int getNSplitter() TGG=9a]m  
{  K\ pZ  
return nSplitter; A9Ea}v9:  
} 7w5l[a/  
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; 1?L  
public void setNSplitter(int nCount) yP-$@Ry  
{ Gl{2"!mt=  
nSplitter = nCount; [=.iJ5,{2  
} 1GR|$E  
} FR50y+h^$  
9P <1/W!  
\N?lG q  
/* %ByqkY{5F  
**Utility.java *hFJI9G  
*/ UDkH'x$=  
package NetFox; j";L{  
e5FF'~A%]  
uW}M1kq?+l  
public class Utility { x5rm 2C  
fK@UlMC]7  
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public Utility() Ygfy;G%  
{ rwwyYIlEg  
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} A;/,</  
H,/=<Th;i  
//线程睡眠 rWM5&M  
public static void sleep(int nSecond) *6_>/!ywI  
{ {RsdI=%  
try{ J+Y?'"r  
Thread.sleep(nSecond); Bq4@I_b  
} .Q</0*sp  
catch(Exception e) IA=\c  
{ =y?Aeqq\fl  
e.printStackTrace (); T9}dgf  
} vXdI)Sx[  
} ow,! 7|m  
Y.52`s6F  
//日志 w1F)R^tU  
public static void log(String sMsg) c2gZ
<[~  
{ .ArOZ{lKD>  
System.err.println(sMsg); )TNG0[  
} qMO(j%N
5  
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iy8Ln,4z(  
public static void log(int sMsg) >"zN`  
{ 7|ACJv6%9  
System.err.println(sMsg); lYm00v6y  
} '|%\QWuZ  
} Aba%QQQ  
"[_gRe*2  
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/* \<}e?Yx%  
**TestMethod.java gZz5P
>^  
*/ mX@xV*  
package NetFox; xf:|lQf  
tOQnxKzu  
C2hB7?UGN  
public class TestMethod { >IKIe  
e/)Vx'd`+  
1B{u4w7S4e  
public TestMethod() oSR;Im<2  
{ ///xx/weblogic60b2_win.exe sw(|EZ7F  
try{ H7{kl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }mk z_P(Z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ( ~>-6Nb 5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); /dR:\ffz2  
fileFetch.start(); tg2+Z\0)4g  
} -?)z@L
c  
catch(Exception e){e.printStackTrace ();} 0}>p)k3&A  

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} =@;\9j  
@# p{,L  

-{*QjP;K  
public static void main(String[] args) UQT=URS  
{ 6I5LZ^/G9  
new TestMethod(); NdI~1kemr  
} %wq;<'W  
} `4|:8@,3{  
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