http断点续传简单实现（java)

/* M.|cl#  
**SiteFileFetch.java Q]9+-p(=  
*/ cBZKt  
package NetFox; ,N[N;Uoj  
import java.io.*; Wchu-]  
import java.net.*; #H'j;=]:  
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q#{.8H-X'  
public class SiteFileFetch extends Thread {
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SiteInfoBean siteInfoBean = null; //文件信息Bean n(i Uc1Y  
long[] nStartPos; //开始位置 ;_o1{?~  
long[] nEndPos; //结束位置 uwQ~4   
FileSplitterFetch[] fileSplitterFetch; //子线程对象 E[:eMJR  
long nFileLength; //文件长度 tx,_0[hZi  
boolean bFirst = true; //是否第一次取文件 /6=IL  
boolean bStop = false; //停止标志 {|KFgQ'\  
File tmpFile; //文件下载的临时信息 ~  4v  
DataOutputStream output; //输出到文件的输出流 aG"j9A~ &  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） WH>=*\  
public SiteFileFetch(SiteInfoBean bean) throws IOException |fL|tkGEa  
{ DFgQ1:6[  
siteInfoBean = bean; P3Wnso  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8#m,TOp  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 50s1o{xwc  
if(tmpFile.exists ()) B0h|Y.S8%1  
{ @U8}K#  
bFirst = false; e=>:(^CS  
read_nPos(); jW,b"[  
} {\1:2UKkr  
else oZD+AF$R  
{ ',WnT:  
nStartPos = new long[bean.getNSplitter()]; sf([8YUd  
nEndPos = new long[bean.getNSplitter()]; ,4Q1[K35B  
} D*%?0  
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} "{;E+-/ aL  
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public void run() a2!U9->!  
{ K2XRKoG  
//获得文件长度 kxanzsSr9  
//分割文件 t)4><22of  
//实例FileSplitterFetch bu?4$O  
//启动FileSplitterFetch线程 %.h&W;  
//等待子线程返回 ]c9\[Kdq}H  
try{ o2 ;  
if(bFirst) o7r7HmA@  
{ o=nF.y  
nFileLength = getFileSize(); n5DS  
if(nFileLength == -1) .E:3I!dH7  
{ *8bj3A]vf  
System.err.println("File Length is not known!"); zA>LrtyK(=  
} 'OACbYgG  
else if(nFileLength == -2) `j1b5&N;7  
{ O"GuVC}B  
System.err.println("File is not access!"); 6MD9DqD  
} H|IG"JB  
else fTOGW`s^  
{ Ob&m&2
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for(int i=0;i<nStartPos.length;i++) +SB>
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{ )n&6= Li  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sTxgU !_  
} AI^!?nJ%'  
for(int i=0;i<nEndPos.length-1;i++) >T#" Im-  
{ q^DQ9B  
nEndPos = nStartPos[i+1]; ~m'8<B5+  
} kaT !  
nEndPos[nEndPos.length-1] = nFileLength; U*:ju+)k  
} f<{f/lU@  
} tb^/jzC  
i'QR-B&Z  
l$&dTI<#  
//启动子线程 I7#^'/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *Fg)`M3g  
for(int i=0;i<nStartPos.length;i++) b8 E{~z  
{ iYf)FPET  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cy(4g-b]@e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), B'e@RhU;  
nStartPos,nEndPos,i); &qzy?/i8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i-}Tt<^  
fileSplitterFetch.start(); J
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} v:P=t2q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;Nw)zS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); QHr'r/0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Uc,J+j0F  
nEndPos = " + nFileLength); >V>`}TIH  
// fileSplitterFetch[nPos.length-1].start(); :}R,a=N  
#N$\d4q9  

0R,.  
//等待子线程结束 gZ|!'  
//int count = 0; kTcW=AXu  
//是否结束while循环 |)C #  
boolean breakWhile = false; P}^Y"zF2  
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while(!bStop) Qo!F?i/ n  
{ Dkx}}E:<  
write_nPos(); 0CvGpM,  
Utility.sleep(500); sYfm]Faz  
breakWhile = true; jz~#K;3=,  
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for(int i=0;i<nStartPos.length;i++) @^<&LG5^  
{ A.mFa1lH  
if(!fileSplitterFetch.bDownOver) 052Cf dq  
{ tDavp:M1v  
breakWhile = false; %gQUog  
break; >9mj/P D  
} $e2+O\.>  
} p>i8aN  
if(breakWhile) q{_f"  
break; 0y t36Du  
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3AglvGK7{  
//count++; }]#z0'Aqsu  
//if(count>4) -L4G)%L\  
// siteStop(); 6.a5%:  
} pY[b[ezb  
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System.err.println("文件下载结束！"); XjCx`bX^<  
} G'u[0>  
catch(Exception e){e.printStackTrace ();} @/?i|!6  
} P(FlU]q  
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//获得文件长度 xMNQT.A  
public long getFileSize() V?'p E  
{ ;N(L,  
int nFileLength = -1; V9SL96'[I  
try{ .%)uCLZr$  
URL url = new URL(siteInfoBean.getSSiteURL()); ?hGE[.(eh]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |/H?\]7  
httpConnection.setRequestProperty("User-Agent","NetFox"); |O6/p7+.  
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int responseCode=httpConnection.getResponseCode(); QuG"]
$  
if(responseCode>=400) 0;@>jo6,!  
{ l*OR{!3H$  
processErrorCode(responseCode); 9) ,|h  
return -2; //-2 represent access is error I*^t!+q$  
} NA/`LaJ  
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String sHeader; +v 3:\#  
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for(int i=1;;i++) [T,^l#S1  
{ Y%kOq`uT=n  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3~bB2APk  
//Utility.log(in.readLine()); EpNN!s=Q  
sHeader=httpConnection.getHeaderFieldKey(i); 14,t  
if(sHeader!=null) A-:k4] {%P  
{ yU&;\'  
if(sHeader.equals("Content-Length")) KUYwc@si\  
{ [tof+0Y6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5 ,-8oEUL  
break; RqGX(Iuv  
} Li}5aK  
} BCe'J!  
else NJ.oME@=  
break; d1\nMm}v  
} xx>hJ!  
} C0/^6Lu"o  
catch(IOException e){e.printStackTrace ();} !CX WoM  
catch(Exception e){e.printStackTrace ();} ObEz0Rj  
[ 5}Q  
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Utility.log(nFileLength); Pb>/b\&JS  
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5]LWWjT  
return nFileLength; 6QY;t:/<  
} L55UeP\  
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5Y^"&h[/  
//保存下载信息（文件指针位置） :=;{w~D  
private void write_nPos() 0=3)`v{S@  
{ GW;%~qH[,  
try{ -grf7w^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U< Xdhgo?
 
output.writeInt(nStartPos.length); b{ xlW }S  
for(int i=0;i<nStartPos.length;i++) [,Go*r  
{ eNK +)<PK(  
// output.writeLong(nPos); W6i{yneW  
output.writeLong(fileSplitterFetch.nStartPos); KH;~VR8"/  
output.writeLong(fileSplitterFetch.nEndPos); =oSd M2  
} C$6FI
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output.close(); lJ-PW\P  
} 8]&:'  
catch(IOException e){e.printStackTrace ();} D?1fY!C:r  
catch(Exception e){e.printStackTrace ();} !`I@Rk]`c  
} 4($"4>BA  
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//读取保存的下载信息（文件指针位置） )e?&'wa>  
private void read_nPos() `R8&(kQ  
{ D;V[9E=g/  
try{ \6SjJ]o>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); s/IsrcfM  
int nCount = input.readInt(); PmE)FthdP(  
nStartPos = new long[nCount]; vlbZ5  
nEndPos = new long[nCount]; O[ird`/  
for(int i=0;i<nStartPos.length;i++) v5S9h[gT  
{ N~O
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nStartPos = input.readLong(); lJu^Bcrv  
nEndPos = input.readLong(); P+hcj p*  
} @Uez2?  
input.close(); mfQ#n!{ZH  
} xeU|5-d'  
catch(IOException e){e.printStackTrace ();} NAvR^"I~  
catch(Exception e){e.printStackTrace ();} . |T=T0^  
} 8mreHa  
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private void processErrorCode(int nErrorCode) 6*9wGLE  
{ @=VxWU  
System.err.println("Error Code : " + nErrorCode); Kt_oo[ey{  
} mgjJNzclL  
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W%g*sc*+  
//停止文件下载 ls 5iE  
public void siteStop() ;AEfU^[  
{ %f1%9YH  
bStop = true; I$xZV?d.  
for(int i=0;i<nStartPos.length;i++) &ry*~"xoh  
fileSplitterFetch.splitterStop(); C:J;'[,S  
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} ?J\&yJ_B  
} MuY:(zC%  
//负责部分文件的抓取 -X
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**FileSplitterFetch.java 4!Js="  
*/ m;OvOc,  
package NetFox; a+^`+p/5  
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import java.io.*; ii)#(b:V  
import java.net.*; :X;G]B .  
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public class FileSplitterFetch extends Thread { *DF3juf~
 
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String sURL; //File URL r[L%ap\{  
long nStartPos; //File Snippet Start Position K|P0nJT  
long nEndPos; //File Snippet End Position +94)BxrY  
int nThreadID; //Thread's ID MgJ6{xzz  
boolean bDownOver = false; //Downing is over ZLkl:'E_  
boolean bStop = false; //Stop identical S>yiD`v  
FileAccessI fileAccessI = null; //File Access interface i1 E|lp)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException a('0l2e<u9  
{ ^{+ry<rS>  
this.sURL = sURL; -N45ni87  
this.nStartPos = nStart; G$<(>"Yr~$  
this.nEndPos = nEnd; E`IXBI  
nThreadID = id; O*xx63%jR  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 t%=7v)IOE  
} oPSPb(.  
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public void run() Ds`e-X)O;\  
{ /G||_Hc  
while(nStartPos < nEndPos && !bStop) eHphM;C  
{ 9z7_D_yN2  

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try{ 7~h3B<  
URL url = new URL(sURL); \]ib%,:YU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *[Hp&6f  
httpConnection.setRequestProperty("User-Agent","NetFox"); LE\*33k_  
String sProperty = "bytes="+nStartPos+"-"; Xoe|]@U`  
httpConnection.setRequestProperty("RANGE",sProperty); n ay\)  
Utility.log(sProperty); p_gN}v  
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InputStream input = httpConnection.getInputStream(); }LUvh  
//logResponseHead(httpConnection); Wg-mJu(  
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byte[] b = new byte[1024]; x93@[B*%  
int nRead; A2'i~_e  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <y
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{ $@AJg  
nStartPos += fileAccessI.write(b,0,nRead); V6g*
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//if(nThreadID == 1) ~;"eNg{T  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aHhLz>H'  
} H=/1d.p  
'@n"'vks(\  
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Utility.log("Thread " + nThreadID + " is over!"); JYdb^j2c  
bDownOver = true; Rk$7jZdTf  
//nPos = fileAccessI.write (b,0,nRead); BtJkvg(2]  
} 
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catch(Exception e){e.printStackTrace ();} ?JuJu1  
} t^#1=nK  
} ^ D0"m>3r  
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//打印回应的头信息 bmT%?it  
public void logResponseHead(HttpURLConnection con) (j8*F Bq  
{ Jz8P':6[  
for(int i=1;;i++) ]3,'U(!+  
{ 0#|Jhmv-zL  
String header=con.getHeaderFieldKey(i); *bK=<{d1P  
if(header!=null) RXXHg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +)c<s3OCE  
Utility.log(header+" : "+con.getHeaderField(header)); ~kc#
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else %Wtf24'o;v  
break; htB2?%S=T  
} 4MC]s~n  
} c)EYXo  
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d>  
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public void splitterStop() '(K4@[3t  
{ B>u`%Ry&  
bStop = true; B)q}]Qn  
} i4YskhT  
I Fw7?G,  
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} 'iMzp]V;  
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MR
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/* ,ei9 ?9J1  
**FileAccess.java /KH85/s  
*//文件访问(定位，写) *zRig|k!H  
package NetFox; Y%}&eN$r  
import java.io.*; 9Qyc!s`  
<EnmH/C.  
5bb#{?2i  
public class FileAccessI implements Serializable{ 0\i\G|5  
CH7a4qL`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @<K<"`~H  
RandomAccessFile oSavedFile; /l`zZ>  
long nPos; -~z@W3\  
0LW3VfvToN  
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public FileAccessI() throws IOException 9DBX.|  
{ :V(C+bm *  
this("",0); .BxI~d^  
} a;$V;3C{b&  
**P P  
1n8y4k)  
public FileAccessI(String sName,long nPos) throws IOException 2dz)rjdO,  
{ U*nB= =  
oSavedFile = new RandomAccessFile(sName,"rw"); Q]5_s{kiz  
this.nPos = nPos; j&ti "|2\  
oSavedFile.seek(nPos); {X?Aj >l  
} / 0$!.  
jJ"(O-<)D  
`U0XvWPr[  
public synchronized int write(byte[] b,int nStart,int nLen) h]@'M1D%  
{ xkf2;  
int n = -1; x`?>j$  
try{ #Q2s3"X[  
oSavedFile.write(b,nStart,nLen); z*HM_u  
n = nLen; jR\pYRK  
} dr#%~I  
catch(IOException e) 7 @\i5  
{ 5[g&0  
e.printStackTrace (); t=lDN'\P  
} GX23c i  
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return n; b~ )@e9  
} jhRr!  
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} Ot.v%D`e 5  
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r5[pT(XT]  
/* T5`ML'Dej  
**SiteInfoBean.java XFTqt]
 
*/ IqlCl>_j  
package NetFox; AyUw  
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?9?A)?O<j~  
public class SiteInfoBean {  G>?kskm  
:}36;n<['  
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private String sSiteURL; //Site's URL AP z"k?D0  
private String sFilePath; //Saved File's Path "Plo[E  
private String sFileName; //Saved File's Name PcbhylKd  
private int nSplitter; //Count of Splited Downloading File S~r75] "  
6 o  
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public SiteInfoBean() .[eC w  
{//nSplitter的缺省值为5 pC,Z=+:  
//default value of nSplitter is 5 ]Vj($O:  
this("","","",5); gdSqG2/&  
} Fa`%MR1  
q%M~gp1  
4n.JRR&;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Uufig)6  
{ tf54EIy5Y  
sSiteURL= sURL; 22ySMtxn  
sFilePath = sPath; 67/\0mV:~  
sFileName = sName; g :B4zlKG  
this.nSplitter = nSpiltter; A*:|d~  
MrUjqv6a[  
DO{otn9<  
} GL>YJ%  
oR8'^G0<  
=mX26l`B  
public String getSSiteURL() uDJ;GD[yc  
{ &=S:I!9;;  
return sSiteURL; k(7Q\JKE  
} hMz)l\0  
}oiNgs/N  
K2Ro0  
public void setSSiteURL(String value) 'Qg!ww7O  
{ ]Ue aXwaU  
sSiteURL = value; K:XP;#OsP  
} aeNbZpFQ  
AB3OG*C9  
4P5^.\.  
public String getSFilePath() 8JQ\eF$ma  
{ !#%>,X#+  
return sFilePath; :J@3:+sr  
} H)S!%(x4  
[\eVX`it  
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public void setSFilePath(String value) Hn(Eut7%  
{ qe(gKKA%q  
sFilePath = value; \K"7U  
} rqp]{?33  
qs\Cwn!  
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public String getSFileName() .9Cy<z  
{ LauGT* z!  
return sFileName; C+M]"{Y+  
} J2 )h":2  
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v,*C>u\3s  
public void setSFileName(String value) ;ow)N <Z  
{ Sx J0Y8#z  
sFileName = value; e T;@pc  
} ^
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.hG*mXw>  
{ir
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public int getNSplitter() A/:_uqm4  
{ AWMJ/E*T  
return nSplitter; 'oY#a9~Z{  
} <FU?^
*~  
]&P\|b1*g  
bW! &n  
public void setNSplitter(int nCount) OE0G*`m  
{ \X\f~CB  
nSplitter = nCount; FP=27=  
} Nc4;2~XwRp  
} zdU46|!u  
}Md;=_TP  
ZQf
PDH=  
/* #O;JV}y  
**Utility.java *-Yw%uR  
*/ ! #! MTk  
package NetFox; \$.{*f   
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d,l?{Ln  
public class Utility { _h#I}uJ~  
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public Utility() %>=6v}f,+  
{ ARf{hiV6Wt  

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}

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LOi}\O8  
//线程睡眠 <nqv)g"u0  
public static void sleep(int nSecond) K6-M.I  
{ e*lL.  
try{ rqmb<# Z  
Thread.sleep(nSecond); f4Y)GO<R]  
} &5R|{',(Y  
catch(Exception e) xIa7F$R 0  
{ =iKl<CqI$E  
e.printStackTrace (); 0]
  
} kq5X<'MM9N  
} 1]~w?)..'  
jmkOu
5@  
//日志 @ G)yz!H  
public static void log(String sMsg) _,T 4DS6  
{ 1F`jptVQ\G  
System.err.println(sMsg); If,p!L  
} |0=UZK7%O  
Is7BJf  
i}DS+~8v  
public static void log(int sMsg) [DM0'4  
{ iI IXv  
System.err.println(sMsg); K$M+"#./  
} *l+Dbm,u  
} *|dr-e_j  
s||" } l  
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/* ^HJ?k:u  
**TestMethod.java JaRsm'SIk~  
*/ \\FT.e
6  
package NetFox; DaQl ip  
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rtj`FH??11  
public class TestMethod { -U=Ci  
yk`qF'4]  
%A$&9c%  
public TestMethod() 9dhEQ=K{3  
{ ///xx/weblogic60b2_win.exe ]A3  
try{ 2aM7zP[Z  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); '*b]$5*p  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @m#OhERv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); LWF,w7v[L  
fileFetch.start(); ;ItH2Lw<&  
} gQ>kDl^$Ls  
catch(Exception e){e.printStackTrace ();} {?H5Pw>{%h  
aaR& -M@  
 -BSdrP|  
} hF,|()E[  
(.ir"\k1(  
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public static void main(String[] args) eluN~T:W  
{ __g k:a>oQ  
new TestMethod(); 5G f@n/M"  
} Y &Cb  
} "o&8\KSs  
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