http断点续传简单实现（java)

/* / +%  
**SiteFileFetch.java p/VVb%  
*/ u;-fG9xs  
package NetFox; xlu4  
import java.io.*; n+hL/aQ+  
import java.net.*; 0V(}Zj>  
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"O<ETHd0  
public class SiteFileFetch extends Thread { 2~?E'  
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SiteInfoBean siteInfoBean = null; //文件信息Bean HNv~ZAzBG-  
long[] nStartPos; //开始位置 Cd"{7<OyM4  
long[] nEndPos; //结束位置 wN4#j}C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !e~[U-  
long nFileLength; //文件长度 C`ky=
 
boolean bFirst = true; //是否第一次取文件 0FI |7  
boolean bStop = false; //停止标志 -|KZOea  
File tmpFile; //文件下载的临时信息 6X%g-aTs  
DataOutputStream output; //输出到文件的输出流 =(D"(OsQ/  
h )5S4)  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &k%>u[Bo  
public SiteFileFetch(SiteInfoBean bean) throws IOException /G'3!S  
{ 3U+FXK#6  
siteInfoBean = bean; E KV[cq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); tOLcnWt   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~vt9?(h  
if(tmpFile.exists ()) :vG0 l\  
{ n*=#jL  
bFirst = false; w"s@q$}]8M  
read_nPos(); FZj>N(  
} \"nut7";2  
else o?hr>b  
{ Lm2)3;ei  
nStartPos = new long[bean.getNSplitter()]; UWvVYdy7  
nEndPos = new long[bean.getNSplitter()]; -R:_o1"  
} cS9jGD92  
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} G#7(6:=;,`  
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7 s5(eQI  
public void run() ufL<L;Z\;  
{ R~k`KuY@!  
//获得文件长度 *??lwvJp  
//分割文件 C\GP}:[T3  
//实例FileSplitterFetch 5P-t{<]tx  
//启动FileSplitterFetch线程 ([dd)QU  
//等待子线程返回 nwUz}em?O  
try{ q_h (D/g  
if(bFirst) Bso#+v5  
{ A,cXN1V  
nFileLength = getFileSize(); F. SB_S<'  
if(nFileLength == -1) j/d}B
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{ y]fI7nu&  
System.err.println("File Length is not known!"); HT.*r6Y>g  
} yQN{)rv  
else if(nFileLength == -2) 7}UG&t{  
{ 6_bL<:xtY  
System.err.println("File is not access!"); =zcvR {Dkp  
} aY>v  
else R;c9)>8L  
{ nJ2x;';lA  
for(int i=0;i<nStartPos.length;i++) '6 F-%
 
{ =x\`yxsG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7*{f*({  
} QH9t |l  
for(int i=0;i<nEndPos.length-1;i++) l\*9rs:!  
{ njaMI8|Pa  
nEndPos = nStartPos[i+1]; 4}uOut  
} )_=2lu3%{  
nEndPos[nEndPos.length-1] = nFileLength; ~(QfVpRnV=  
} K8sRan[4}  
} ~I@lsCh  
W-n4wIj"  
vyIH<@@p7  
//启动子线程 E>|X'I?r^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4?'vP'  
for(int i=0;i<nStartPos.length;i++) k6;bUOo  
{ EyE#x_A  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z_\p8@3aH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), QkdcW>:a7  
nStartPos,nEndPos,i); 4\Y5RfLB_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0+*NHiH  
fileSplitterFetch.start(); "^n,(l*4x  
} J{1H$[W~}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7~mhWPzMwB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); EJ
9hgE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a4__1N^Qj  
nEndPos = " + nFileLength); U\Wo&giP[  
// fileSplitterFetch[nPos.length-1].start(); tbd=A]B-  

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,|({[9jA  
//等待子线程结束 ){5Nod{}a  
//int count = 0; @owneSD qN  
//是否结束while循环 S'jg#*$  
boolean breakWhile = false; T$xBH  
;/j2(O^  
>CqzC8JF  
while(!bStop) ukW&\  
{ FQDf?d5  
write_nPos(); [X.bR$>  
Utility.sleep(500); }aVZ\PDg  
breakWhile = true; 3 !@  
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for(int i=0;i<nStartPos.length;i++) Q!e560@  
{
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if(!fileSplitterFetch.bDownOver) :CyHo6o9  
{ :}lqu24K  
breakWhile = false; X g6ezl
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break; FPDTw8" B;  
} y2G Us&09  
} vjuFVJwL  
if(breakWhile) Xo34~V@(  
break; |`5IP8Z  
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//count++; N T`S)P*?  
//if(count>4) 'u7-Qetj  
// siteStop(); hxO}'`:  
} bO=|utpk  
 x]+PWk  
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System.err.println("文件下载结束！"); s<9g3Gh  
} 6l]X{A.  
catch(Exception e){e.printStackTrace ();} AI-*5[w#A  
} 2*|T)OA`m,  
k {
*QU(  
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//获得文件长度 &]nx^C8V;  
public long getFileSize() _v,0"_"  
{ hJb2y`,q  
int nFileLength = -1; ]:|
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try{ r7m~.M+W"  
URL url = new URL(siteInfoBean.getSSiteURL()); 'a['lF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \CL8~  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4ba*Nc*Yc  
54+(o6E<  
h: ' |)O  
int responseCode=httpConnection.getResponseCode(); m\L`$=eO8  
if(responseCode>=400) b2m={q(s  
{ 3e_tT8
  
processErrorCode(responseCode); /Nf{;G!kg  
return -2; //-2 represent access is error $TI^8 3  
} i+Z)`  
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7*!7EBb  
String sHeader;  Aqyw  
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v ,8;: sD  
for(int i=1;;i++) <RGH+4LF  
{ =@HS  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /eF@a!  
//Utility.log(in.readLine()); mptFd  
sHeader=httpConnection.getHeaderFieldKey(i); /Z:
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if(sHeader!=null) #,%bW[L<N  
{ ?d7,0Ex P  
if(sHeader.equals("Content-Length")) PsC")JS  
{ p}1i[//S  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); C= ~c`V5>r  
break; =&}@GsXdo  
} ^4dE8Ve"@  
} {q-&!l|  
else J2bvHxb Rd  
break; qX\*lm/l  
} Pq;OShU_  
} -@pjEI  
catch(IOException e){e.printStackTrace ();} 0HzqU31%l@  
catch(Exception e){e.printStackTrace ();} AkhG~L  
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Utility.log(nFileLength); k9Pvh,_wp  
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return nFileLength; ;*A'2ymXUT  
} q~ H>rC(\  
"r9Rr_, >  
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//保存下载信息（文件指针位置） s|=lKa]d!"  
private void write_nPos() ARKM[]  
{ NXW*{b  
try{ u,^CFws_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hFrMOc&  
output.writeInt(nStartPos.length); OM86C  
for(int i=0;i<nStartPos.length;i++) |5&+VI  
{ GEc6;uz<  
// output.writeLong(nPos); 0U '"@A \  
output.writeLong(fileSplitterFetch.nStartPos); Y|>dS8f;4  
output.writeLong(fileSplitterFetch.nEndPos); VoU8I ~  
} U0x A~5B  
output.close(); YvR bM  
} -ss= c
#  
catch(IOException e){e.printStackTrace ();} USg"wJY  
catch(Exception e){e.printStackTrace ();} acd[rjeT  
} ~iL^KeAp   
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//读取保存的下载信息（文件指针位置） "#Rh\DQ  
private void read_nPos() O0 'iq^g  
{ &V].,12x  
try{ yW_yHSx;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I2Xd"RHN  
int nCount = input.readInt(); @\K[WqF$$q  
nStartPos = new long[nCount]; vsY?
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nEndPos = new long[nCount]; #}`sfaT  
for(int i=0;i<nStartPos.length;i++) ~6G `k^!  
{ R~vGaxZ$  
nStartPos = input.readLong(); d$t"Vp  
nEndPos = input.readLong(); Bo
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} 2HX/@ERhmu  
input.close(); -l^<[%  
} j*{0<hZb}  
catch(IOException e){e.printStackTrace ();} !~ox;I}S  
catch(Exception e){e.printStackTrace ();} ;Afz`Se1@  
} p~D}Iyww1_  
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private void processErrorCode(int nErrorCode) b1&tk~D  
{ fvu{(Tb  
System.err.println("Error Code : " + nErrorCode); amBg<P`'_  
} !/FRL<mp  
7=^{~5#  
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//停止文件下载 ohx[_}xN  
public void siteStop() ?nU<cxh  
{ n]%-2`}(  
bStop = true; TW|K.t@5#H  
for(int i=0;i<nStartPos.length;i++) VkQ@c;C  
fileSplitterFetch.splitterStop(); [+ud7l  
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} 55Ss%$k@  
} qZ1'uln=C-  
//负责部分文件的抓取 ~?Zib1f)  
**FileSplitterFetch.java PR:k--)D  
*/ bo0U  
package NetFox; Pv -4psdw  
HDj6E"  
FI.te3i?7  
import java.io.*; fBSa8D3}`  
import java.net.*;  a"Qf  
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public class FileSplitterFetch extends Thread { n`Q@<op  
K;F1'5+=D  
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String sURL; //File URL #M-!/E  
long nStartPos; //File Snippet Start Position 9"~ FKMN  
long nEndPos; //File Snippet End Position
Z#[?~P  
int nThreadID; //Thread's ID DAn2Pqf  
boolean bDownOver = false; //Downing is over \"lz,bT  
boolean bStop = false; //Stop identical HC iRk1  
FileAccessI fileAccessI = null; //File Access interface V_
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{j2V k)\[i  
mLCDN1UO{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (0-Ol9[  
{ %:3XYO.w-  
this.sURL = sURL; F*72g)hVh  
this.nStartPos = nStart; RQVu~7d[  
this.nEndPos = nEnd; >0^<<=m  
nThreadID = id; EX,>V,.UV  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 EPm~@8@"j?  
} 
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public void run() : |'(T[~L  
{ (r|m&/  
while(nStartPos < nEndPos && !bStop) 05d0p|},
 
{ F8pA)!AH  
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try{ )+.=z  
URL url = new URL(sURL); 3?Pg ;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mjeJoMvN)H  
httpConnection.setRequestProperty("User-Agent","NetFox"); `Ba]i)!  
String sProperty = "bytes="+nStartPos+"-"; #g{R+#fm  
httpConnection.setRequestProperty("RANGE",sProperty); -FZC|[is  
Utility.log(sProperty); fi?4!h  
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InputStream input = httpConnection.getInputStream(); yD+4YD  
//logResponseHead(httpConnection); '*J+mZtN  
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byte[] b = new byte[1024]; r:*G{m-  
int nRead; ON2o^-%=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j=r1JV @  
{ IeYYG^V<A  
nStartPos += fileAccessI.write(b,0,nRead); _ *f>UW*,  
//if(nThreadID == 1) omE- c  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,s8/6n#  
} +_GS@)L`%  
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4]o+)d.`(  
Utility.log("Thread " + nThreadID + " is over!"); Y'U1=w~E  
bDownOver = true; nCQtn%j't  
//nPos = fileAccessI.write (b,0,nRead); =%<=Bn  
} hGtz[u#p  
catch(Exception e){e.printStackTrace ();} PR8nJts W5  
} Xf u0d1b  
} Q-7?'\h  
] Q5:JV  
.psb#4  
//打印回应的头信息 ACRuDY  
public void logResponseHead(HttpURLConnection con) Ht[$s40P  
{ &'uP?r9c$  
for(int i=1;;i++) #Y7jNrxE
  
{ '1mk;%  
String header=con.getHeaderFieldKey(i); O= S[n  
if(header!=null) VLXA6+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); MK1\  
Utility.log(header+" : "+con.getHeaderField(header)); k]m ~DVS  
else P$EiD+5#z  
break; jVff@)_S  
} lV\iYX2#  
} 1K Vit{  
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public void splitterStop() 
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{ LG[N\%<!H  
bStop = true; .S//T/3O]Q  
} [)"\Aq  
}0'LKwIR  
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} -1Q24jrO-  
#,#`<h!  
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/* #pvq9fss,}  
**FileAccess.java [F6)Z[uG  
*//文件访问(定位，写) +|/0sPW(  
package NetFox; M%E<]H2;S  
import java.io.*; M<-Q8a~  
;,77|]<XE  
u W]gBhO$O  
public class FileAccessI implements Serializable{ <K CI@  
.W{CJh  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 QAkK5,`vV.  
RandomAccessFile oSavedFile; 5wue2/gl  
long nPos; 78l);/E{v  
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public FileAccessI() throws IOException V0;"Qa@q  
{ ^lp=4C9  
this("",0); lOm01&^"E  
} iT'doF  
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public FileAccessI(String sName,long nPos) throws IOException xJ>5 ol  
{ =Kj{wA O  
oSavedFile = new RandomAccessFile(sName,"rw"); uE1;@Dm+  
this.nPos = nPos; #D9.A7fCc5  
oSavedFile.seek(nPos); /@\`Ibe  
} k[f2`o=  
8?Rp2n*o  
#B\s'j[A"  
public synchronized int write(byte[] b,int nStart,int nLen) OlT8pG5Oa  
{ }+@!c%TCx~  
int n = -1; rl}<&aPH  
try{ Ar<5UnT  
oSavedFile.write(b,nStart,nLen); 6Z|h>H5a  
n = nLen; 0OO[@Ht  
} 9"#C%~=+  
catch(IOException e) p_I^7 $  
{ $b`nV4p  
e.printStackTrace (); b-ss^UL  
} rd7p$e=i  
lp(2"$nQ  
( v*xW.  
return n; _:[@zxT<x  
} xt|^~~ /  
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} q8P&rMwy  
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/* X):7#x@uy  
**SiteInfoBean.java XP)^81i|  
*/ =\lw.59  
package NetFox; # Wi?I=,  
~61b^L}$  
d.?}>jl  
public class SiteInfoBean { #@oB2%&X?  
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pg%(6dqK4  
private String sSiteURL; //Site's URL x=cucZ  
private String sFilePath; //Saved File's Path i D9 */  
private String sFileName; //Saved File's Name ]In7%Qb  
private int nSplitter; //Count of Splited Downloading File [mzed{p]]  
SMrfEmdH+  
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public SiteInfoBean() 3O,nNt;L{  
{//nSplitter的缺省值为5 UN'n~d@~  
//default value of nSplitter is 5 eA7 Iv{M  
this("","","",5); 8?iI;(  
} @eJ8wf]  
a,Pw2Gcid  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) oMN<jAU.  
{ @<P2di  
sSiteURL= sURL; n~UI47  
sFilePath = sPath; wH?)ZL  
sFileName = sName; + ,Krq 3P  
this.nSplitter = nSpiltter; l/={aF7+  
^2- <XD)  
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} VgVDTWs7  
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=  
TVcA%]y{;  
public String getSSiteURL() E!ndXz 59  
{ 7?yS>(VmT  
return sSiteURL; K T0t4XPM  
} Go{,< gm  
"AUSgVE+h  
u9~5U9]O%6  
public void setSSiteURL(String value) A1/@KC"&{G  
{ :&wb+tV  
sSiteURL = value; xnMcxys~  
}  !64Tx  
2{?]W/&fS  
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public String getSFilePath() ]mMJ6n  
{ 7_\F$bp`  
return sFilePath; !p+54w\ 2  
} 4-.W~C'Q  
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public void setSFilePath(String value) ]qqgEZ1!Y  
{ rnZ$Qk-H  
sFilePath = value; "`ftcJUd  
} lQ?jdi  
Wu 0:X*>}p  
_Gq6xv\b1  
public String getSFileName() &B&8$X  
{ !hq2AY&H)  
return sFileName; r>(,)rs(l  
} -Fd&rq:GB(  
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public void setSFileName(String value) $6Q^ur:  
{ mcQL>7ts  
sFileName = value; SO6)FiPy!n  
} ASHU0v  
AtJ{d^  
u79- B-YW^  
public int getNSplitter() f(pq`v^-n  
{
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return nSplitter; ^m%#1Zd  
} Uuy$F  
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RKP,w%  
public void setNSplitter(int nCount) jae9!Wi  
{ /-p!|T}w  
nSplitter = nCount; K#+?oFo:  
} {|u"I@M*O  
} ^i%S}VK  
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d#v@NuO6 h  
/* ]i#p2?BR  
**Utility.java h&i*=&<HP6  
*/ yIL=jzm`7  
package NetFox; cuN]}=D  
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JVuju$k  
public class Utility { nmU1xv_  
XX/gS=NE#.  
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public Utility() H<Sf0>OA  
{ ^+76^*0  
B)Y[~4o  
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} 2'@m'4-N  
elR'e6Q  
//线程睡眠 JjS+'A$A5  
public static void sleep(int nSecond) y`va6 %u{  
{ uHI(-!O  
try{ -!XG>Z  
Thread.sleep(nSecond); ]B3](TH"  
} 4Et(3[P71  
catch(Exception e) hty'L61\z  
{ fLe~X!#HF  
e.printStackTrace (); ZoXz@/T  
} z&gmaYwq  
} (S!UnBb&  
Y$L` G  
//日志 +fk*c[FG  
public static void log(String sMsg) 7z$Z=cs  
{ 2{h2]F  
System.err.println(sMsg); 8b?nr;@  
} QH-CZ6M  
eJo" Z  
{<ShUN  
public static void log(int sMsg) Rv&"h_"t  
{ jg?UwR&  
System.err.println(sMsg); 4

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} G^Gs/- f  
} U"7o;q  
X_2N9$},  
w80
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/* K(?V]Mxl6  
**TestMethod.java Q("m*eMRt  
*/ uU 7 <8G  
package NetFox; WPRk>j  
hq7f"`  
G0 EXgq8  
public class TestMethod { P7-k!p"  
%<>:$4U@]  
$L^%*DkM  
public TestMethod() 5$=[x!x  
{ ///xx/weblogic60b2_win.exe tKt}]KHV  
try{ 5b:1+5iF-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \$_02:#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "zcAYg^U  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $jMA(e`Ye0  
fileFetch.start(); ~ =u8H  
} [^ }$u[  
catch(Exception e){e.printStackTrace ();} ?r !kKMZ  
sa+ JN^[X  
h-PJC/>  
} MUl`0H"tR  
=Q9^|&
6  
SPV+ O{  
public static void main(String[] args) '^)'q\v'k  
{ sc]#T)xG  
new TestMethod(); qefp3&ls  
} Gt*<Awn8  
} :z8/iD y  
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