http断点续传简单实现（java)

/* *=AqM14 @  
**SiteFileFetch.java Hc^W%t~  
*/ #P<N^[m  
package NetFox; #]P9b@@e  
import java.io.*; ,<-G<${  
import java.net.*; !-<p,z  
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public class SiteFileFetch extends Thread { F+m }#p  
3ZEB  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]:>,A@7  
long[] nStartPos; //开始位置 $5x ,6[&  
long[] nEndPos; //结束位置 +M' H0-[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8N&+7FK  
long nFileLength; //文件长度 VTy9_~q  
boolean bFirst = true; //是否第一次取文件 \K`L3*cBKK  
boolean bStop = false; //停止标志 0:w"M<80  
File tmpFile; //文件下载的临时信息 #7ohQrP  
DataOutputStream output; //输出到文件的输出流 #$1Z
 
>zAUW[]C:I  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） mKrh[nA  
public SiteFileFetch(SiteInfoBean bean) throws IOException ktIi$v  
{ %\]*OZ7  
siteInfoBean = bean; *Kdda} J+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (e(:P~Ry  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !?c|XdjZ  
if(tmpFile.exists ()) YIw1  
{ iQDx{m3]  
bFirst = false; vz.>~HBP  
read_nPos(); (x/k.&  
} Cj~'Lhmv'T  
else zR2B- &]H  
{ '%q$`KDb  
nStartPos = new long[bean.getNSplitter()]; 3EJt%}V$k  
nEndPos = new long[bean.getNSplitter()]; (=7Cs  
} xJ#d1[kzo  
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} ep)>X@t  
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public void run() ,^uEYT}j  
{ 8F._9U-EN  
//获得文件长度 YW7b)uYf  
//分割文件 (1#J%  
//实例FileSplitterFetch c%MW\qx  
//启动FileSplitterFetch线程 yu;P +G  
//等待子线程返回 zux{S;:?  
try{ U&?v:&c#&n  
if(bFirst) j KoG7HH  
{ x QIq^/F0  
nFileLength = getFileSize(); ZpnxecJUJ  
if(nFileLength == -1) Q)IKOt;N]  
{ H'  
System.err.println("File Length is not known!"); Evedc*z~P  
} [PDNwh0g5  
else if(nFileLength == -2) .>WxDQIo  
{ #w' k
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System.err.println("File is not access!"); zzX_q(:S  
} cLLbZ=`  
else U H*r5o3  
{ Fvbh\m ~  
for(int i=0;i<nStartPos.length;i++) |aVn&qK  
{ <$IM8Y5p+w  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~XOTs  
} a ?)NC  
for(int i=0;i<nEndPos.length-1;i++) /w}u3|L$  
{ =,6z4" )  
nEndPos = nStartPos[i+1]; NU5.o$  
} x8V('`}j  
nEndPos[nEndPos.length-1] = nFileLength; 9-fLz?J  
} NgP&.39U  
} ~v|>xqWV  
%5"9</a&G  
\D*KGd]M0  
//启动子线程 @eKec1<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; hvsWs.;L'  
for(int i=0;i<nStartPos.length;i++) Z/Dx,zIR  
{ Ju1D =b  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), klT@cO-9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >JFO@O5  
nStartPos,nEndPos,i); o<pf#tifv  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); sN9&,&W1  
fileSplitterFetch.start(); i#vYyVr[  
} 3sy (vC  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #Y a4ps_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @1o/0y"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", wsI`fO^A8  
nEndPos = " + nFileLength); &m)6J'q3k  
// fileSplitterFetch[nPos.length-1].start(); gG(fQ 89U"  
#P0&ewy  
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//等待子线程结束 q_A!'sm@)  
//int count = 0; `ZyI!"  
//是否结束while循环 4.[^\N  
boolean breakWhile = false; 0"  
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>UiYL}'br6  
while(!bStop) _=F=`xu  
{ yerg=,$_i  
write_nPos(); Jh,]r?Bd  
Utility.sleep(500); 9
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breakWhile = true; e>+i>/Fn{h  
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 mHdA2  
for(int i=0;i<nStartPos.length;i++) {Aw#?#GPW  
{ ZxGJzakB5$  
if(!fileSplitterFetch.bDownOver) tdBm (CsN  
{ n8~N$tDU  
breakWhile = false; [1g8*j~L  
break; {6|38$Rl  
} pjKWtY@=X  
} _.tVSVp  
if(breakWhile) <\rT%f}3^  
break; 2=,lcWr  
V_:1EBzz  
6m*QX+  
//count++; AYqX
|  
//if(count>4) :~&~y-14  
// siteStop(); {f3YsM;]C  
} 1H? u Qy  
?uzRhC_)!  
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System.err.println("文件下载结束！"); k:t]s_`<  
} T*Y~\~Jhu  
catch(Exception e){e.printStackTrace ();} cLpYW7vZ[  
} #xsE3Wj-X  
6M @[B|Q(  
44ek IV+?  
//获得文件长度 ,>bh$|  
public long getFileSize() vYwYQG  
{ -;s|  
int nFileLength = -1; hgYZOwQ  
try{ `uv2H$  
URL url = new URL(siteInfoBean.getSSiteURL()); M8kPj8}{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M'7fO3&|  
httpConnection.setRequestProperty("User-Agent","NetFox"); PS)4 I&;U  
kj#?whK6~  
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int responseCode=httpConnection.getResponseCode(); | k&Ck  
if(responseCode>=400) !,wIQy_e4  
{ \:%(q/v"X  
processErrorCode(responseCode); lHN5Dr  
return -2; //-2 represent access is error %P;lv*v.  
} dP9qSwTa  
 ~^NtO  
I&D5;8  
String sHeader; hQ,ch[j'  
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2%DSUv:H%  
for(int i=1;;i++) .[]r}[lU  
{ l5S aT,%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;km`P|
<U  
//Utility.log(in.readLine()); {{$Nqn,pH  
sHeader=httpConnection.getHeaderFieldKey(i); -o^7r@6  
if(sHeader!=null) (!ux+K  
{ 3
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if(sHeader.equals("Content-Length")) LA!?H]  
{ [;n9:Qxf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2,DXc30I  
break; kKaE=H-x  
} m(r,Acy6  
} NH[kNi'  
else 1T"`vtR  
break; 9g9HlB&Ze  
} zIqU,n|]s  
} T:27r8"Rh  
catch(IOException e){e.printStackTrace ();} %6|nb:Oa  
catch(Exception e){e.printStackTrace ();}
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Utility.log(nFileLength); 3lf=b~Zi
)  
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return nFileLength; JB%',J  
} vDp8__^  
2":pE U{E  
!8TlD-ZT/  
//保存下载信息（文件指针位置） %:M^4~dc  
private void write_nPos() ,1y@Z 5wy  
{ f/U`  
try{ /MIe(,>Uh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); T`9lV2x*P  
output.writeInt(nStartPos.length); 'F/~o1\.  
for(int i=0;i<nStartPos.length;i++) :N:yLd} &  
{ EuEZ D+  
// output.writeLong(nPos); OC_+("N  
output.writeLong(fileSplitterFetch.nStartPos); R}-(cc%5  
output.writeLong(fileSplitterFetch.nEndPos); %41m~Wh2  
} 4)S,3G  
output.close(); >Rl"  
} DHyq^pJ  
catch(IOException e){e.printStackTrace ();} e2AX0(  
catch(Exception e){e.printStackTrace ();} S-a]j;U  
} I5X|(0es  
&u]8IEv}u  
9)h"-H;5:  
//读取保存的下载信息（文件指针位置） )cW#Rwu_A4  
private void read_nPos() qFicBpB  
{ {dhXIs  
try{ Yz'K]M_Dq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kI,yU}<Fq  
int nCount = input.readInt(); '3R`lv   
nStartPos = new long[nCount]; ;nI] !g:  
nEndPos = new long[nCount]; M-$%Rzl_  
for(int i=0;i<nStartPos.length;i++) OyU5DoDz1  
{ Q1
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nStartPos = input.readLong(); (j%~u&+-  
nEndPos = input.readLong(); M=8.Bp|Ye  
} 5 )A1\  
input.close(); 6`&a&%,O  
} eln)BW#  
catch(IOException e){e.printStackTrace ();} ]l;o}+`G  
catch(Exception e){e.printStackTrace ();} im${3>26  
} R#s)r  
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private void processErrorCode(int nErrorCode) {yBs7[Wn  
{ FXpJqlhNv  
System.err.println("Error Code : " + nErrorCode); kC:uG0sW  
} TeMHm?1^  
mbKZJ{|4s  
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//停止文件下载 5A,K6f@:g  
public void siteStop() @CNi{. RX
 
{ 7dN*lks  
bStop = true; 2\)xpOj  
for(int i=0;i<nStartPos.length;i++) &r[`>B{tP  
fileSplitterFetch.splitterStop(); zU,9T  
 |{&{  
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} b\ X@gq  
} #"}JdBn  
//负责部分文件的抓取 \|n- O=}=2  
**FileSplitterFetch.java M5i%jZk  
*/ XP`Nf)3{Yd  
package NetFox; ajve~8/&  
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import java.io.*; W4t;{b  
import java.net.*; -Sqz5l
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public class FileSplitterFetch extends Thread { ov|d^)'  
f<-Jg  
oxr#7Ei0d  
String sURL; //File URL BIH-"vTy  
long nStartPos; //File Snippet Start Position T!uM+6|Y  
long nEndPos; //File Snippet End Position mR!1DQ.\<  
int nThreadID; //Thread's ID c& <Fr[AK  
boolean bDownOver = false; //Downing is over X enE^e+9  
boolean bStop = false; //Stop identical O],T,Z?z  
FileAccessI fileAccessI = null; //File Access interface V[mT<Lc  
k3~}7]O)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException b}\N;D.{  
{ <xup'n^7C  
this.sURL = sURL; #+JG(^%B  
this.nStartPos = nStart; 9q)Kfz  
this.nEndPos = nEnd; GeI-\F7b  
nThreadID = id; ]{!U@b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5CuuG<0  
} >d@&2FTO  
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public void run() vp1941P  
{ 02Y]`CXj  
while(nStartPos < nEndPos && !bStop) xP_cQwm`1  
{ # q~e^A b  
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try{ FSP+?((  
URL url = new URL(sURL); bw(a6qKK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1Vsz4P"O $  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5
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String sProperty = "bytes="+nStartPos+"-"; ,k.3|aZE  
httpConnection.setRequestProperty("RANGE",sProperty); +ndaLhj'  
Utility.log(sProperty); Moy <@+  
Ha(c'\T(\  
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InputStream input = httpConnection.getInputStream(); i6R~`0>Q  
//logResponseHead(httpConnection); ()2I#  
*jLJcb*.Ap  
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byte[] b = new byte[1024]; $>G8_q  
int nRead; :Hn6b$Vy8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ng[Ar`  
{ vhe>)h*B  
nStartPos += fileAccessI.write(b,0,nRead); [I0:=yJ+  
//if(nThreadID == 1) fA&k`L(y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); # Nk;4
:[  
} 1=r#d-\tR  
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Utility.log("Thread " + nThreadID + " is over!"); 6q*9[<8  
bDownOver = true; \"qY"V  
//nPos = fileAccessI.write (b,0,nRead); Bu#E9hJFvA  
} t 4PK}>QW  
catch(Exception e){e.printStackTrace ();} %huRsQ%}  
} l2`s! ,<>O  
} :Uz|3gq  
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//打印回应的头信息 IW>T}@ |  
public void logResponseHead(HttpURLConnection con) "&%I)e
^  
{ dOa+(f
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for(int i=1;;i++) a!ud{Dx  
{ #G.ulX  
String header=con.getHeaderFieldKey(i); 7[w,:9& }  
if(header!=null) BD68$y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,
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Utility.log(header+" : "+con.getHeaderField(header)); c(J!~7  
else }
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break; ?QsQnQ  
} e_#._Pi  
} |P[w==AAf  
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public void splitterStop() uPhK3nCGo  
{ %kv0Wefs  
bStop = true; n\QgOSr<  
} ~kQA7;`j$  
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} 9G9fDG#F\I  
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/* %4ePc-  
**FileAccess.java H!?c\7adX  
*//文件访问(定位，写) 0":ib0=  
package NetFox; M|6A0m#Q  
import java.io.*; t5[#x4 p  
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public class FileAccessI implements Serializable{ ,#Iu 7di  
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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 *#E FsUw  
RandomAccessFile oSavedFile; 4NGA/ G  
long nPos; QFw  +cy  
:QpuO1Gu  
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public FileAccessI() throws IOException i'4B3  
{ 6`O.!
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this("",0); { D^{[I  
} ~R_ztD+C(  
0KYEb%44  
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public FileAccessI(String sName,long nPos) throws IOException M\sN@+  
{ ,u!*2cWN  
oSavedFile = new RandomAccessFile(sName,"rw"); ?kWC}k{  
this.nPos = nPos; m6TNBX  
oSavedFile.seek(nPos); >*]Hq.&8  
} X*M#F
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public synchronized int write(byte[] b,int nStart,int nLen) >ZPsjQuf"  
{ eCN })An  
int n = -1; bvS(@  
try{ |K6REkzr  
oSavedFile.write(b,nStart,nLen); )>.&N[
v  
n = nLen; c\iA89msp  
} vI2^tX9  
catch(IOException e) z8QAo\_I(  
{ ?3%`bY+3;  
e.printStackTrace (); >_o}  
} N F2/B#q  
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return n; "$N#p5  
} }2(,K[?  
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} Q7R~{5r>W  
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/* Qk\A c  
**SiteInfoBean.java 6b+b/>G0  
*/ l7W 6qNB  
package NetFox; Ko;{I?c  
A3|Dz&@:  
CPP` qt%f  
public class SiteInfoBean { &z>e5_.  
,_yhz0.  
x*?x=^I{  
private String sSiteURL; //Site's URL #gp,V#T  
private String sFilePath; //Saved File's Path 0Uz\H0T1  
private String sFileName; //Saved File's Name >Y #t`6,!  
private int nSplitter; //Count of Splited Downloading File rypTKT|U;  
<(-3_s6-  
AT9q3  
public SiteInfoBean() lD"(MQV@0  
{//nSplitter的缺省值为5 r.#t63Rb  
//default value of nSplitter is 5 31rx-D8o  
this("","","",5); 3~}uqaGt  
} KcK>%%  
#
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O+?<h{"  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) H2um|6>  
{ 6 G3\=)  
sSiteURL= sURL; m9"n4a|:  
sFilePath = sPath; >p.O0G gg  
sFileName = sName; J(c{y]`J  
this.nSplitter = nSpiltter; |g #K]v  
J.ck~;3  
COW}o~3-4  
} $: ]o]a  
rb1`UG"h$  
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public String getSSiteURL() =|I>G?g-  
{ 5m9*85Ib  
return sSiteURL; WAn~+=Ax  
} .Fnwm}  
~$p2#AqX  
jBU4F~1y  
public void setSSiteURL(String value) $OP7l>KZY  
{ NGOqy+Ty{f  
sSiteURL = value; VUhbD  
} L ]w/P|  
Yc,7tUz#  
tQH+)*  
public String getSFilePath() iVd.f A  
{ DwrO JIy  
return sFilePath; \'9PZ6q{  
} L+CyQq  
|fSe>uVZ  
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public void setSFilePath(String value) GKoK7qH\J  
{ 6S+U&Ce\  
sFilePath = value; /)dFK~  
} ;$a@
J&  
#*TEq
 
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public String getSFileName() DSt]{fl`P  
{ /w]!wM  
return sFileName; 2Sh  
} Er{#ziN+  
~M\I;8ne  
7}vg.hmZ  
public void setSFileName(String value) Rr!Y3)f;  
{ z,VD=Hnz  
sFileName = value; u-tQ9ioKC  
} A?`jnRo=\  
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public int getNSplitter() ,}:G\u*Fu  
{ Gkp<o  
return nSplitter; F35#dIs`&  
} :"l-KQ0  
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public void setNSplitter(int nCount) `\m*+Bk[5  
{ Bf$_XG3  
nSplitter = nCount; ONCnVjZ  
} ^k Cn*&  
} .58qL-iC  
-CRraEXf8  
Y& F=t/U2  
/* =&},;VOh  
**Utility.java QjC22lW-  
*/ tqy@iEz+  
package NetFox; [xT:]Pw}  
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0d3+0EN{  
public class Utility { !wWJ^Oz=  
1]}#
)-  
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public Utility() !o>H1#2l  
{ sF7^qrVQP9  
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} z.6$W^  
m~>Y{F2  
//线程睡眠 9W8]8sUeG  
public static void sleep(int nSecond) 3( ]M{4j  
{ !=y]Sv~h  
try{ ^::E
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Thread.sleep(nSecond); W;1|+6x  
} IJJ%$%F/  
catch(Exception e) *#TYqCc+g  
{ .)+hH y  
e.printStackTrace (); 1pCieTz!PN  
} !bC+TYsU  
} 2jbIW*  
ZbT/$\0(6  
//日志 x)UwV  
public static void log(String sMsg) l?iSxqdT  
{ a,o_`s<  
System.err.println(sMsg); m{7^EF  
} j
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[|~2X>  
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public static void log(int sMsg) WO6/X/#8b  
{ 4G@nZn  
System.err.println(sMsg); )XfzLF7  
} w0ZLcND{  
} ]?h`:,]  
f,z P*  
'u4ezwF;  
/* "v}pdUW  
**TestMethod.java {u[V{XIUh  
*/ 5[{*{^F4  
package NetFox; ^VT1vu %03  
>\ u<&>i  
__@zTSVb  
public class TestMethod { hCYQGx0  
4gSH(*}  
+Ug/rtK4  
public TestMethod() 81%8{yn!$"  
{ ///xx/weblogic60b2_win.exe |B
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try{ idRD![!UI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >O/D!j|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `Y40w#?uW  
SiteFileFetch fileFetch = new SiteFileFetch(bean); zNSu  
fileFetch.start(); I =Wc&1g  
} g`k?AM\  
catch(Exception e){e.printStackTrace ();} Q/I)V2a1i  
to"'By{9  
}%TSGC4{  
} 3E^M?N2oc  
c~<1':  
-V %gVI[  
public static void main(String[] args) v=I|O%  
{ ]+DI.%   
new TestMethod(); *pzq.#  
} "k$JP  
} >cL{Ya}Rz  
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