http断点续传简单实现（java)

/* O]G3l0  
**SiteFileFetch.java o^+g2;Ro  
*/ Xe@:Aun  
package NetFox; vGD D  
import java.io.*; %APeQy"6#^  
import java.net.*; dI~{0)s
 
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public class SiteFileFetch extends Thread { h3MZLPe  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #f }OR
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long[] nStartPos; //开始位置 &o7"L;  
long[] nEndPos; //结束位置 CMU\DO  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 s\q m  
long nFileLength; //文件长度 c='uyx  
boolean bFirst = true; //是否第一次取文件 sH :_sOV*  
boolean bStop = false; //停止标志 kD#hfYs)i  
File tmpFile; //文件下载的临时信息 AIt;~x  
DataOutputStream output; //输出到文件的输出流 !0Eo9bU%@  
}W nvz;]B  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） tWA<OOl  
public SiteFileFetch(SiteInfoBean bean) throws IOException no7Q%O9  
{ $q0i=l&$&  
siteInfoBean = bean; 7?qR
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); InB'Ag"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [cw>; \J  
if(tmpFile.exists ()) im"3n=  
{ 3EA`]&d>  
bFirst = false; Sw~L M&A  
read_nPos(); $uYfy<  
} +H "j-:E@t  
else zj7?2  
{ ~jMfm~  
nStartPos = new long[bean.getNSplitter()]; Y9y'`}+  
nEndPos = new long[bean.getNSplitter()]; ;f9a0Vs  
} AO]1`b:  
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} p~h[4hP  
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public void run() I0}G, q  
{ mC./,a[  
//获得文件长度 ,`ju(ac!  
//分割文件 52'0l>  
//实例FileSplitterFetch U
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//启动FileSplitterFetch线程 Sj
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//等待子线程返回 \OK"r-IO  
try{ |/~ISB  
if(bFirst) *m:'~\[u  
{ nD#uOep9  
nFileLength = getFileSize(); zC>zkFT>H  
if(nFileLength == -1) ?5rM'O2  
{ h[r)HX0hA  
System.err.println("File Length is not known!"); dS;Ui]/J  
} SfUbjs@a  
else if(nFileLength == -2) a`8svo;VUO  
{ Gw?ueui<  
System.err.println("File is not access!"); k5eTfaxl  
} KqFiS9 N5  
else VMJK9|JC[  
{ |!uC [=  
for(int i=0;i<nStartPos.length;i++) |!*abc\`(`  
{ c->?'h23)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -e_B  
} K8/I+#j  
for(int i=0;i<nEndPos.length-1;i++) $fQ'q3  
{ 17yg ~  
nEndPos = nStartPos[i+1]; 7!^Zsp^+  
} ]`TX%Qni  
nEndPos[nEndPos.length-1] = nFileLength; >o!5)\F  
} e/F+Tf  
} G'WbXX  
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//启动子线程 PvVn}i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %DuSco"  
for(int i=0;i<nStartPos.length;i++) e)A{ {wD/  
{ apv"s+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %p tw=Ju  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ZG1 {"J/z  
nStartPos,nEndPos,i); 9DaoMOPEI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #An_RU6h  
fileSplitterFetch.start(); vz`r !xj)  
} !-s6B  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mZ4I}_\,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &|c] U/_w  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", js)I%Z  
nEndPos = " + nFileLength); yr34&M(a  
// fileSplitterFetch[nPos.length-1].start(); iK9#{1BpML  
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^LAdN8Cbb  
//等待子线程结束 R1C2d+L  
//int count = 0; J
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//是否结束while循环 ~0Xx]  
boolean breakWhile = false; xoNn
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while(!bStop) `(pe#Xxn  
{ A?Gk8  
write_nPos(); uG7ll5Yy  
Utility.sleep(500); m'5rzZP  
breakWhile = true; J3AS"+]  
- xQJY)  
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for(int i=0;i<nStartPos.length;i++) 7.7Z|lJ  
{ l5,}yTUta  
if(!fileSplitterFetch.bDownOver) 6cbIs_g  
{ ^li(q]g1!  
breakWhile = false; 5vjtF4}7!  
break; 7G9o%!D5  
} cK6IyJx-  
} F+::UWKA  
if(breakWhile) #{suH7  
break; Z*lZl8(`  
=.f<"P51k  
<" F|K!Tz  
//count++; 4dUr8]BkG  
//if(count>4) Dp" xO<PE2  
// siteStop(); j!hdi-aTU  
} c`4i#R
 
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System.err.println("文件下载结束！"); s+E-M=d0e  
} 0vi\o`**Mj  
catch(Exception e){e.printStackTrace ();} L+d4&x  
} WU<C7  
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GXx/pBdy[4  
//获得文件长度 lO dwH"  
public long getFileSize() iXFN|ml  
{ Ikj_ 0/%F  
int nFileLength = -1; Vh;P,no#  
try{ ,?Nc\Q<:  
URL url = new URL(siteInfoBean.getSSiteURL()); Xw{Qktn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?ZlN$h^  
httpConnection.setRequestProperty("User-Agent","NetFox"); [wR x)F"  
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int responseCode=httpConnection.getResponseCode(); f1}b;JJTsv  
if(responseCode>=400) sH{4.tw  
{ %<Te&6NU
'  
processErrorCode(responseCode); u!K5jqP  
return -2; //-2 represent access is error >KMTxHE`+  
} #Yr/GNN  
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e x`mu E  
String sHeader; TWAt
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for(int i=1;;i++) )A H)*Mg  
{ ? {vY3~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z=\wI:TY1  
//Utility.log(in.readLine()); H@!kgaNF
 
sHeader=httpConnection.getHeaderFieldKey(i); z'd*z[L~  
if(sHeader!=null) sQ8_j  
{ %44Z7  
if(sHeader.equals("Content-Length")) 
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{ A*_ |/o
 
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); j[y,Jch  
break; zM*PN|/%sH  
} vynchZ+g]  
} Oe:_B/l  
else 0?d}Oj  
break; gm}[`GMU  
} _ZU.;0  
} {&Es3+{A  
catch(IOException e){e.printStackTrace ();} "T,^>xD  
catch(Exception e){e.printStackTrace ();} Z>+Tzvfud  
#:6gFfk0<  
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Utility.log(nFileLength);  y+.E}  
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return nFileLength; dN)!B!*aI  
} v<wR`7xG  
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rxVJB3P9  
//保存下载信息（文件指针位置） s$ v<p(yl  
private void write_nPos() =$t  
{ eED@Z/~
6  
try{ 'E#;`}&Ah  
output = new DataOutputStream(new FileOutputStream(tmpFile)); iAAlld1  
output.writeInt(nStartPos.length); AJ`R2 $  
for(int i=0;i<nStartPos.length;i++) onOvE Y|R  
{ Sd0y=!Pj=  
// output.writeLong(nPos); NEG&zf  
output.writeLong(fileSplitterFetch.nStartPos); wmf#3"n  
output.writeLong(fileSplitterFetch.nEndPos); f/Q7WXl0  
} {F~:86z(g  
output.close(); c3NUJ~>=y  
} )5(Ko<"  
catch(IOException e){e.printStackTrace ();} etHkyF  
catch(Exception e){e.printStackTrace ();} BDCFToSf|  
} HECZZnM  
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//读取保存的下载信息（文件指针位置） Q:4euhz*  
private void read_nPos() ^%:syg_RM[  
{ {_{&t>s2  
try{ (i*;V0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); aAX(M=3  
int nCount = input.readInt(); z]Jpvw`p  
nStartPos = new long[nCount]; O)4P)KAO<  
nEndPos = new long[nCount]; EhBYmc"&  
for(int i=0;i<nStartPos.length;i++) +UTs2*H/^  
{  @aC2]  
nStartPos = input.readLong(); `?PpzDV7Y  
nEndPos = input.readLong(); Ef2#}%>  
} [qEd`8V(  
input.close(); ee=d*)  
} *ydU3LG7  
catch(IOException e){e.printStackTrace ();} HAi'0%"  
catch(Exception e){e.printStackTrace ();} ]1XJQW@gF  
} =H\ig%%E@  
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private void processErrorCode(int nErrorCode) I>jDM  
{ R3dCw:\O+Z  
System.err.println("Error Code : " + nErrorCode); 3;h%mkKQ+  
} vV?=r5j  
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?l3PDorR  
//停止文件下载 5l&9BS&  
public void siteStop() zeZ}P>C  
{ y_=},a  
bStop = true; }8W5m(Zq9n  
for(int i=0;i<nStartPos.length;i++) qrj:H4#VB  
fileSplitterFetch.splitterStop(); =[$zR>o*%  
-0{"QhdE%  
$ 4& )  
} -Xw i}/OX  
} *UJ&9rQ
 
//负责部分文件的抓取 ;3D[[
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**FileSplitterFetch.java 9? #pqw  
*/ ezC2E/#  
package NetFox; F^v <z)x  
n;eK2+}]  
@\=%M^bx  
import java.io.*; XSu9C zx&I  
import java.net.*; uH6QK\  
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public class FileSplitterFetch extends Thread { sKkk+-J4  
/puM3ZN  
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String sURL; //File URL `qjiC>9  
long nStartPos; //File Snippet Start Position YXR%{GUP[  
long nEndPos; //File Snippet End Position q0oNRAvn"  
int nThreadID; //Thread's ID tWNz:V  
boolean bDownOver = false; //Downing is over ;34 m!\N5  
boolean bStop = false; //Stop identical wuv2bd )+  
FileAccessI fileAccessI = null; //File Access interface ZS-O,[  

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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?W%9H\;  
{ 6+MZ39x
C  
this.sURL = sURL; gX}(6RP_!  
this.nStartPos = nStart; Uv(THxVh  
this.nEndPos = nEnd; ?E@9Nvr  
nThreadID = id; *uLlf'qU]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `[.':"~2N  
} B/(]AWi+  
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public void run() `g;`yJX<  
{ .H,wdzg)  
while(nStartPos < nEndPos && !bStop) 8h&Ed=gi  
{ /A U& X  
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try{ *g}(qjl<  
URL url = new URL(sURL); ;_yp@.,\T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UqaLTdYG  
httpConnection.setRequestProperty("User-Agent","NetFox"); OZ*V7o  
String sProperty = "bytes="+nStartPos+"-"; }*2q7K2bj  
httpConnection.setRequestProperty("RANGE",sProperty); >g+ogwZ  
Utility.log(sProperty); PXZZPW/  
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InputStream input = httpConnection.getInputStream(); 7R 40t3  
//logResponseHead(httpConnection);  )"im|9  
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byte[] b = new byte[1024]; AwhXCq|k  
int nRead; AXV+8$ :R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y7{9C*>  
{ p/|":(U  
nStartPos += fileAccessI.write(b,0,nRead); !$&3h-l[  
//if(nThreadID == 1) }";\8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k!gf
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} [@U2a$k+d  
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Utility.log("Thread " + nThreadID + " is over!"); niZ/yW{w  
bDownOver = true; ncEOz1u  
//nPos = fileAccessI.write (b,0,nRead); QU/Q5k  
} QRs!B!Fn0  
catch(Exception e){e.printStackTrace ();} T@PtO"r  
} A$K>:Tt>  
} 0jY#,t?>  
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//打印回应的头信息 {wWh;  
public void logResponseHead(HttpURLConnection con) <lHelX=/  
{ Mf0XQ3n`H  
for(int i=1;;i++) nRpZ;X)'.  
{ :NL.#!>/  
String header=con.getHeaderFieldKey(i); CD\
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if(header!=null) JzA`*X[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); YYrXLt:  
Utility.log(header+" : "+con.getHeaderField(header)); iyw"|+  
else o(iN}.c  
break; w$~|/UrLf  
} 8iTX}$t\{  
} p&wXRI  
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public void splitterStop() #un#~s 7Q  
{ ~Uw**PT3M  
bStop = true; #4. S2m4  
} k^3|A3A  
9/OB!<*V|  
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} !br0s(|  
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/* e[fzy0  
**FileAccess.java A~ugx~S0  
*//文件访问(定位，写) L1"y5HJ  
package NetFox; SRq0y,d  
import java.io.*; &(h~{  
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public class FileAccessI implements Serializable{ cT abZc  
IS0RhtGy/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 f $MVgX  
RandomAccessFile oSavedFile; gTRm  
long nPos; mA:NAV$!s  
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8=x{>&Jr&#  
public FileAccessI() throws IOException V.PbAN  
{ _K{hq<g  
this("",0); *9}2Bmojv  
} JF]HkH_u  
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public FileAccessI(String sName,long nPos) throws IOException L 0kK'n?  
{ y?W8FL  
oSavedFile = new RandomAccessFile(sName,"rw"); 1P&XG@  
this.nPos = nPos; cF_hU"  
oSavedFile.seek(nPos); ^y"Rdv  
} b]hP;QK`U$  
n0#HPI"  
afRUBjs  
public synchronized int write(byte[] b,int nStart,int nLen) :`6E{yfM  
{ O.S(H1z<G  
int n = -1; Jq)!)={  
try{ <\c5
 
oSavedFile.write(b,nStart,nLen); qy6zHw  
n = nLen; CN0&uyu#4  
} g9OO#C>  
catch(IOException e) B3u
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{ 5!,`LM9  
e.printStackTrace (); ;
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} rgheq<B:  
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return n; CZg$I&x  
} S!o!NSn@1  
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} rz0~W6
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/* :.Vn  
**SiteInfoBean.java zZDa71>  
*/ h_L-M}{OG  
package NetFox; aB~?Y+m  
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public class SiteInfoBean { Yd:8iJA  
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private String sSiteURL; //Site's URL S{aK\>>H  
private String sFilePath; //Saved File's Path pA9^-:\*  
private String sFileName; //Saved File's Name ($&i\e31N  
private int nSplitter; //Count of Splited Downloading File J
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public SiteInfoBean() D_@WB.eL  
{//nSplitter的缺省值为5 <zH24[  
//default value of nSplitter is 5 +s.r!?49+  
this("","","",5); u-0-~TwD  
} 0t?:  
4vcUHa|4  
_!kL7qJ"  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) , }O>,AU  
{ 1foy.3g-  
sSiteURL= sURL; $NzD&b$7  
sFilePath = sPath;  Hrm^@3  
sFileName = sName;  RSXYz8{  
this.nSplitter = nSpiltter; Fu:VRul=5$  
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} .~qu,q7k~  
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public String getSSiteURL() F Cg{!h  
{ 'v iF8?_  
return sSiteURL; =m6;]16D  
} E c[-@5x  
)*ocX)AE  
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public void setSSiteURL(String value) 2bwf(  
{ uH S)  
sSiteURL = value; y}dop1zp  
} 4`Qu+&4J  
CEjMHP$=  
=n|n%N4Y  
public String getSFilePath() 5SKj% %B2,  
{ EEmYfP[3  
return sFilePath; 0w}OE8uq  
} W
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Cc7PhoPK  
public void setSFilePath(String value) v {E~R  
{ 3:1 h:Yc<  
sFilePath = value; Y}BT| "  
} 9BgR@b  
+
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public String getSFileName() x TEDC,B  
{ QyN<o{\FD!  
return sFileName; gOaL4tu  
} W=j  
| wuUH  
YD1 :m3l!  
public void setSFileName(String value) C,$$bmS=  
{ HC4qP9Gs  
sFileName = value; T@0\z1,~S  
} |E)-9JSRy  
#)hc^gIO&<  
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public int getNSplitter() J_) .Hd  
{ :(gZ\q">k  
return nSplitter; I\eM8`Y$  
} . Z 93S|q  
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public void setNSplitter(int nCount) iOk^RDG+  
{ ^5n"L29V  
nSplitter = nCount; znm3b8ns  
} 08*bYJu  
} q5<'pi   
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/* Z_^i2eJYT  
**Utility.java RJ+i~;-  
*/ 701ei;  
package NetFox; -L=aZPW`M  
:5`=9_|  
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public class Utility { Q7uhz5oZ  
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public Utility() <OF2\#Nh  
{ k0[b4cr`  
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} tCZ3n  
{p -q&k&R|  
//线程睡眠 [1Cs  
public static void sleep(int nSecond) <0R$yB  
{ ']]Czze  
try{ f,S,35`qa  
Thread.sleep(nSecond); `v;9!ReZV  
} of?hP1kl[  
catch(Exception e) `[.b>ztqgJ  
{ wrtJ8O(  
e.printStackTrace (); M1UabqQ  
} cOz8YVR-  
} =v-qao7xCV  
Fog4m=b`g  
//日志 nd~cpHQR^  
public static void log(String sMsg) 'IVNqfC)u  
{ ,0j7qn@tm  
System.err.println(sMsg); _c[Bjip  
} VTM*=5|c  
 Xaz`L  
/#WRd}IjK  
public static void log(int sMsg) |AgdD  
{ V]4g- CS[  
System.err.println(sMsg); :.2Tcq  
} D7v-+jypp  
} S}mZU!  
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:9nqQJ+~  
/* \&tv *  
**TestMethod.java >d/DXv 3  
*/ ,tZJSfHB  
package NetFox; G&2UXr3  
^v5v7\!  
`=}w(V8pc  
public class TestMethod { `1O<UJX  
_BC%98:WP  
whoM$  &  
public TestMethod() KM'*+.I  
{ ///xx/weblogic60b2_win.exe 1$+-?:i C  
try{ $G\IzK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); oSAO0h>0N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 
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SiteFileFetch fileFetch = new SiteFileFetch(bean); .zm/GtOV@  
fileFetch.start(); F=T};b  
} AbqeZn  
catch(Exception e){e.printStackTrace ();} 8ch^e[U`  
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h vC gd^M  
} >^fpQG  
=qg;K'M5  
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public static void main(String[] args) E((U=P}+g  
{ sWG_MEbu  
new TestMethod(); ~4T:v_Q7g  
} AlVBhR`  
} *_qLLJg  
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