http断点续传简单实现（java)

/* 6E0{(*  
**SiteFileFetch.java XJ{b_h#N  
*/ ,'c?^ $J|z  
package NetFox; G ;fc8a[X  
import java.io.*; rUOl+p_47  
import java.net.*; W&H
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public class SiteFileFetch extends Thread { ne-;gTP;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean lOJ3_8  
long[] nStartPos; //开始位置 dub%fs  
long[] nEndPos; //结束位置 g+  P  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 uqFYa bU  
long nFileLength; //文件长度 7v{s?h->$  
boolean bFirst = true; //是否第一次取文件 3sF^6<E  
boolean bStop = false; //停止标志 n,vs(ZL:  
File tmpFile; //文件下载的临时信息 WPbG3FrL!  
DataOutputStream output; //输出到文件的输出流 N,F$^ q6  
Yv ZcG3@c3  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ( {}Z '  
public SiteFileFetch(SiteInfoBean bean) throws IOException %{*)-_M  
{ d]!`II  
siteInfoBean = bean; NPY\ >pf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W<s
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); G}8Zkz@+  
if(tmpFile.exists ()) i?0+f}5<p  
{ `%oJa`  
bFirst = false; 4k4 d%  
read_nPos();
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} &K@ RTgb  
else }?KfL$@$  
{ -Mx\W|YK  
nStartPos = new long[bean.getNSplitter()]; uW4wTAk;qh  
nEndPos = new long[bean.getNSplitter()]; H)VzPe#{  
} |ryV7VJ8  
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} %ok??_}$}q  
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public void run() TpIx!R9  
{ n4%ZR~9WH  
//获得文件长度 RF$2p4=[  
//分割文件 qGVf!R  
//实例FileSplitterFetch K}e:zR;;^  
//启动FileSplitterFetch线程 Z(c3GmY  
//等待子线程返回 7xU6Ll+p  
try{ RJhafUJ zH  
if(bFirst) aTLu7C\-e  
{ SR8)4:aKW  
nFileLength = getFileSize(); 6>=yX6U1q^  
if(nFileLength == -1) |x#w8=VP-  
{ lC8Z@wkjO  
System.err.println("File Length is not known!"); (2uF<$7(  
} aP&bW))CI  
else if(nFileLength == -2) 3[F9qDAy  
{ PXrv2q[5?  
System.err.println("File is not access!"); "\`>Ll  
} hteAuz4H  
else EJ@&vuDd$  
{ v1O1-aM  
for(int i=0;i<nStartPos.length;i++) >h3m/aeNC  
{ V]Z!x.x"=y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =8V 9E  
} zN3b`K. i  
for(int i=0;i<nEndPos.length-1;i++)  ,7h0y  
{ HE|XDcYO  
nEndPos = nStartPos[i+1]; ,[UK32KWI  
} Y!qn[,q8  
nEndPos[nEndPos.length-1] = nFileLength; aM7=>  
} aDZ,9}  
} N}gPf i  
vN9R.R  
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//启动子线程 'zhv#&O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; L.?QZN%cN  
for(int i=0;i<nStartPos.length;i++) Lvd es.0|  
{ B? Z_~Bf&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7SJR_G6,{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^V7'
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nStartPos,nEndPos,i); zQ~ax!}R  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {&ykpu090  
fileSplitterFetch.start(); H!P$p-*.  
} A9_}RJ9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r#'ug^^k$X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); e);`hNLih  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^).  
nEndPos = " + nFileLength); ~JQ6V?fucD  
// fileSplitterFetch[nPos.length-1].start(); <&RpGAk%I  
Jo''yrJpB  
i_e%HG  
//等待子线程结束 4$+1&
+@ ]  
//int count = 0; \IaUsx"#o{  
//是否结束while循环 = glF6a  
boolean breakWhile = false; 46##(4RF  
$f?GD<}?7r  
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while(!bStop) T5Iz{Ha  
{ MfZamu5+F  
write_nPos(); l;d4Le  
Utility.sleep(500); }jg1..)"<  
breakWhile = true; ON9L+"vqv0  
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for(int i=0;i<nStartPos.length;i++) zY9CoadZ  
{ 2]]}
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if(!fileSplitterFetch.bDownOver) &=]!8z=  
{ lK_T%1Gz  
breakWhile = false; #mYe@[p@  
break; Re+oCJ  
} @ZRg9M:N  
} xXlx}C  
if(breakWhile) 2@W`OW Njm  
break; ;nrkC\SYh:  
pgQ^w0BQV  
R^B8** N  
//count++; Dn)B19b  
//if(count>4) x_t$*  
// siteStop(); MOPHu O{^  
} =ld!=II  
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System.err.println("文件下载结束！"); m>|7&l_  
} "~S2XcR[ E  
catch(Exception e){e.printStackTrace ();} # [ +n(  
} O`$\Plt|v  
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k!bG![Ie|  
//获得文件长度 l$[,V:N  
public long getFileSize() =d+`xN*  
{ Apj[z2nr  
int nFileLength = -1; *pDS%,$xe  
try{ e
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URL url = new URL(siteInfoBean.getSSiteURL()); ~k%XW$cV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l[i1,4  
httpConnection.setRequestProperty("User-Agent","NetFox"); F|cli <  
9kwiG7V1  
97 ,Yq3  
int responseCode=httpConnection.getResponseCode(); \GV'{W+o2  
if(responseCode>=400) =dwy 4  
{ zKI1  
processErrorCode(responseCode); I2krxLPd  
return -2; //-2 represent access is error | #b/EA9  
} q&}+O  
VoQhzp6&  
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String sHeader; 8)2M%R\THn  
<Ql2+ev6  
_2)QL  
for(int i=1;;i++) 0|i|z!N>  
{ \%9QE  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); GHo mk##0E  
//Utility.log(in.readLine()); Lxv6\3I+  
sHeader=httpConnection.getHeaderFieldKey(i); G*,7pc  
if(sHeader!=null) g[HuIn/  
{ g7lPQ_A*  
if(sHeader.equals("Content-Length")) tK?XU9o  
{ a]Y9;(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7F_N{avr  
break; Bj"fUI!dK  
} FUZuS!sJ  
} m
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else ]>ndFE6kl  
break; MttFB;Tp  
} mxu!$wx  
} ~w9`l8/0  
catch(IOException e){e.printStackTrace ();} xn@oNKD0  
catch(Exception e){e.printStackTrace ();} UI'fzlB  
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Utility.log(nFileLength); Pp_? z0M  
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return nFileLength; 0LSJQ9\p  
} [
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*cCj*Zr]  
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//保存下载信息（文件指针位置） 1)qD)E5&cf  
private void write_nPos() 3OY(L`  
{ ?A24h!7  
try{ Y"^.6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); rhX?\_7o  
output.writeInt(nStartPos.length); e.#,9  
for(int i=0;i<nStartPos.length;i++) ZG{#CC
=  
{ |5&7;;$  
// output.writeLong(nPos); Y7 K2@257  
output.writeLong(fileSplitterFetch.nStartPos); (ip3{d{CT]  
output.writeLong(fileSplitterFetch.nEndPos); "DH>4Q] d  
} t<$J 3h/"  
output.close(); }RYPr  
} PnB2a'(^@?  
catch(IOException e){e.printStackTrace ();} CC'N"Xb  
catch(Exception e){e.printStackTrace ();} OECVExb@eH  
} S v#,L8f  
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52,'8` ]  
//读取保存的下载信息（文件指针位置） p,uM)LD  
private void read_nPos() =W2I0nr.  
{ opu)9]`z  
try{ Snp(&TD<<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )vg@Kc26  
int nCount = input.readInt(); rY1jC\  
nStartPos = new long[nCount]; :_nGh]%  
nEndPos = new long[nCount]; ;B(16&l=q  
for(int i=0;i<nStartPos.length;i++) G `B=:s]  
{ %nE%^Enw  
nStartPos = input.readLong(); \q24E3zS&  
nEndPos = input.readLong(); 8<KC-|y.  
} B<$6Dj%L  
input.close(); gw%L M7yQR  
} (?lT @RY/  
catch(IOException e){e.printStackTrace ();} >Rb jdM5K4  
catch(Exception e){e.printStackTrace ();} IjQgmS~G  
} {i3=N{5b  
l
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private void processErrorCode(int nErrorCode) _F^NX%  
{ TV0Y{x*~iH  
System.err.println("Error Code : " + nErrorCode); olXfR-2>1  
} 9}42s+  
+%~me?  
:O?3lj)  
//停止文件下载 3O_O5  
public void siteStop() &zVXd  
{ H7<g5pv  
bStop = true; 1|>bG#|  
for(int i=0;i<nStartPos.length;i++) }*aj&  
fileSplitterFetch.splitterStop(); qF`]}7"^  
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2 '$nz  
} *#@{&Q(Qh  
} \8vZZt  
//负责部分文件的抓取 _G/uDP%  
**FileSplitterFetch.java l <Z7bo  
*/ YG*}F|1  
package NetFox; l2wu>Ar7.  
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import java.io.*; Fta=yH}  
import java.net.*; km`";gUp>  
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public class FileSplitterFetch extends Thread { $?LegX  
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String sURL; //File URL ?[DVYP  
long nStartPos; //File Snippet Start Position ' 8Q}pp`  
long nEndPos; //File Snippet End Position /N./l4D1K-  
int nThreadID; //Thread's ID `}a-prT<f  
boolean bDownOver = false; //Downing is over XXD4T9Wy  
boolean bStop = false; //Stop identical 9OlJC[  
FileAccessI fileAccessI = null; //File Access interface zU4*FXt  
3-[+g}kak?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %/_E8GE  
{ X2P8Zq=%a  
this.sURL = sURL; fN9uSnu  
this.nStartPos = nStart; Fa{[kJ8z  
this.nEndPos = nEnd; 0a,B&o1  
nThreadID = id; KR%NgV+}!0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 GK3cQw  
} ^ 7)H;$  
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*
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public void run() 1.Neg|  
{ BXytAz3  
while(nStartPos < nEndPos && !bStop) gXY]NWI  
{ U_UN& /f  
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try{ bY~V?yNgKM  
URL url = new URL(sURL); {T0Au{88H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~{{7y]3M-  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3XncEdy_  
String sProperty = "bytes="+nStartPos+"-"; n9Vr*RKM)  
httpConnection.setRequestProperty("RANGE",sProperty); X3~@U7DU  
Utility.log(sProperty); vSCJ xSt#e  
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InputStream input = httpConnection.getInputStream(); yEkwdx5!(  
//logResponseHead(httpConnection); /#?!9c  
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byte[] b = new byte[1024]; aeEio;G1  
int nRead; zkd^5A; `  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) d9l2mJzW  
{ ;RMevVw|  
nStartPos += fileAccessI.write(b,0,nRead); `1lGAKv  
//if(nThreadID == 1) p]7IoO -@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,=: -&~?  
} RQ8;_)%  
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Utility.log("Thread " + nThreadID + " is over!"); BP1<:T'.q`  
bDownOver = true; HzsQ`M4cA  
//nPos = fileAccessI.write (b,0,nRead); w=5<mw  
} N_l_^yD  
catch(Exception e){e.printStackTrace ();} hzA+,  
} $M$-c{>s  
} ,G[Y< ~Hy  
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//打印回应的头信息 n(
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public void logResponseHead(HttpURLConnection con) oFsV0 {x%)  
{ s? 2ikJq  
for(int i=1;;i++) bKEiS8x  
{ Mt@Ma ]!  
String header=con.getHeaderFieldKey(i); $KP&#;9  
if(header!=null) B#3Q4c$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {+EnJ"  
Utility.log(header+" : "+con.getHeaderField(header)); 1jpft3*x  
else Zg|l:^E  
break; 0g#xQzE  
} F 1l8jB\  
} bRr3:"=sE  
$weC '-n@  
&q#. >  
public void splitterStop() L-%'jR  
{ OP\L  
bStop = true; 8Y:x+v5  
} b.RFvq5Z  
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Ar<!F/  
} Lyit`j~yH  
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/* KN>h*eze  
**FileAccess.java p6ryUJc6  
*//文件访问(定位，写) 7m}fVLk  
package NetFox; k$>5v +r0  
import java.io.*; <kWkc|zBY  
9!.S9[[N  
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public class FileAccessI implements Serializable{ gdq6jz  
E'NS$,h  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '8(UiB5d  
RandomAccessFile oSavedFile; X,{[R |  
long nPos; DO(3hIj  
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}0iHf'~DH*  
public FileAccessI() throws IOException JoZSp"R  
{ "oyBF CW  
this("",0); zg$ag4%Qgg  
} B#cN'1c  
h4+*ssnYV  
{R_ <m$  
public FileAccessI(String sName,long nPos) throws IOException Kmw #Q`  
{ qw>vu7/z  
oSavedFile = new RandomAccessFile(sName,"rw"); *LuRo  
this.nPos = nPos; SpYmgL?wJ  
oSavedFile.seek(nPos); |o'r?"  
} L27WDm^)  
'+3C2!  
*2rc
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public synchronized int write(byte[] b,int nStart,int nLen) X*:,|  
{ 7_jlNr7uk  
int n = -1; o8v,178  
try{ lJdYR'/Wd  
oSavedFile.write(b,nStart,nLen); wNn=JzP  
n = nLen; c?REDj2  
} ael] {'h]  
catch(IOException e) *M_^I)*L  
{ `S.I,<&  
e.printStackTrace (); 7upWM~H^  
} !l Egta[Ql  
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return n; 7#NHPn  
} $G5:/,Q  
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} |\/\FK]?]  
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/* C"%B>e  
**SiteInfoBean.java u6Wan*I?  
*/ e+D]9wM8  
package NetFox; }`%ks  
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public class SiteInfoBean { ts}OE  
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private String sSiteURL; //Site's URL nMfR<%r  
private String sFilePath; //Saved File's Path E^br-{|{  
private String sFileName; //Saved File's Name c))?9H ,e)  
private int nSplitter; //Count of Splited Downloading File 8DY:a['-d  
CV_M |  
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public SiteInfoBean() ^y KkWB*  
{//nSplitter的缺省值为5 t|hc`|  
//default value of nSplitter is 5 X1o^MMpz(F  
this("","","",5); vy{k"W&S  
} u[Si=)`VPk  
zy n
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>]xW{71F@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) QB!_z4UJ_;  
{ Y6Cm PxOQ  
sSiteURL= sURL; FfrC/"N  
sFilePath = sPath; CCol>:8{P  
sFileName = sName; G5K?Q+n   
this.nSplitter = nSpiltter; _aF8Us  
P}UxA!  
HLG5SS7  
} >u(^v@Ejf  
}LKD9U5;8  
h6^|f%\w*i  
public String getSSiteURL() i*m;kWu,  
{ ~:o$}`mW  
return sSiteURL; OKK Ko`RN  
} cz/cY:o)  
doHE]gC2Uz  
[fV"tf;  
public void setSSiteURL(String value) =~Qg(=U0U  
{ r|DIf28MIq  
sSiteURL = value; REE.8_  
} =_zo  
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public String getSFilePath() 6kLy!QS  
{ l~f3J$Ok
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return sFilePath; zow8 Q6f  
} 3di;lzGq  
*jWh4F,  
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public void setSFilePath(String value) !/u  
{ l!Xj UnRF  
sFilePath = value; +$nNYD  
} )UF'y{K}  
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public String getSFileName() kk6 !krZ  
{ ~mXzQbe p  
return sFileName; Nc{&AV8Y_v  
} y&5 O
)  
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tz
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public void setSFileName(String value) BO7HJF)a  
{ XX%K_p`&Z  
sFileName = value; Kc2y  
} uGb+ *tD  
!Md6Lh%-w  
l1'v`!  
public int getNSplitter() L@s6u+uu  
{ P658 XKE  
return nSplitter; mHW%:a\L  
} p<L{e~{!7f  
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public void setNSplitter(int nCount) F%o!+%&7  
{ (XmmbAbVom  
nSplitter = nCount; 'q$Ym0nL  
} ?Ce=h+l  
} U!r8}@  
~ E6e~  

6wWhM&Wd  
/* v9Ii8{ca|  
**Utility.java dt"/4wCO  
*/ }aE'  
package NetFox; ~&T U  
/kK*%TP  
dV :}  
public class Utility { (:OMt2{r  
&(Fm@ksh\  
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public Utility() }vU/]0@,E  
{ /"D,gn1S*  
t*H2
;|zn_  
^`id/  
} c:0n/DC  
n5UUoBv  
//线程睡眠 f|w;u!U(  
public static void sleep(int nSecond) Ly8=SIZ   
{ e_Hpai<b  
try{ [>a3` 0M  
Thread.sleep(nSecond); 96~y\X@x  
} Bc }o3oc  
catch(Exception e) NN'pBUR  
{ Bh=t%#y|`  
e.printStackTrace (); 81y<Uz 6  
} zX*5yNd  
} K |=o-  
~8nR3ki  
//日志 ~%=%5}  
public static void log(String sMsg) U&])ow):  
{ oc] C+l  
System.err.println(sMsg); oX:&;KA  
} 8,IF%Z+LI  
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e`={_R{N  
public static void log(int sMsg) q
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{ Cscu   
System.err.println(sMsg); myX&Z F_9  
} U"8Hw@  
} 80lhhqRC  
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lq_UCCnv5  
/* qypF}Pw  
**TestMethod.java cKkH*0B5  
*/ SS%Bde&<{  
package NetFox; bR"4:b>K  
-JEPh!oTt  
PZ6R+n8  
public class TestMethod { &PV%=/-J  
U=KUx  
JjI1^FRd  
public TestMethod() ({Md({|  
{ ///xx/weblogic60b2_win.exe Axb=1_--  
try{ Ix_w.f=8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); AcnY6:3Y|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); qB_s<cpn>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); HRE?uBkjf  
fileFetch.start(); &1T)'Bn  
} >2>/ q?  
catch(Exception e){e.printStackTrace ();} h@O\j
&#  
zdPJ>PNU  
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}  o%j?}J7y  
@Hp%4$=  
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public static void main(String[] args) OT$Ne  
{  ~ e?af  
new TestMethod(); V Zbn@1  
} y7h^_D+Ce  
} }[|9vF"g.y  
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