http断点续传简单实现（java)

/* ws([bS2h  
**SiteFileFetch.java ~vscATQ  
*/ -%ftPfm  
package NetFox; oU/{<gs  
import java.io.*; SH5a&OVZhn  
import java.net.*; "KKw\
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public class SiteFileFetch extends Thread { 7m.>2U  
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SiteInfoBean siteInfoBean = null; //文件信息Bean mIW/x/I  
long[] nStartPos; //开始位置 aflBDo1c  
long[] nEndPos; //结束位置 miB+
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 il[waUfmD  
long nFileLength; //文件长度 ^0g!,L  
boolean bFirst = true; //是否第一次取文件 2rWPqG4e  
boolean bStop = false; //停止标志 V|vXxWm/  
File tmpFile; //文件下载的临时信息 ]-{A"tJ  
DataOutputStream output; //输出到文件的输出流 dfMi]rs!<  
b#W(&b^q  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .c]@xoC  
public SiteFileFetch(SiteInfoBean bean) throws IOException fn, YH  
{ eZ|_wB'r  
siteInfoBean = bean; i'3)5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); EQVa8xt/C  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6$&%z Eh  
if(tmpFile.exists ()) T_ga?G<  
{ mCSt.n~  
bFirst = false; giHqc7-PaX  
read_nPos(); dYZB> OS  
} F13vc~$Ky  
else C#@-uo2  
{ 9;ie[sU:u  
nStartPos = new long[bean.getNSplitter()]; ]2rCn};  
nEndPos = new long[bean.getNSplitter()]; v<vaPvW  
} Sr>5V  
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3 p!t_y|SX  
}
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@}ioK=A  
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public void run() V
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{ Qov*xRO6  
//获得文件长度 %+oV-o\ #A  
//分割文件 KvumU>c#A  
//实例FileSplitterFetch TU^s!Tj  
//启动FileSplitterFetch线程 KidbcZ  
//等待子线程返回 *})Np0k  
try{ GI%9T
if  
if(bFirst) qT^0 %O:  
{ BeFXC5-qat  
nFileLength = getFileSize(); Xb.# =R  
if(nFileLength == -1) ({mlA`d]  
{ Z@i,9 a  
System.err.println("File Length is not known!"); H^XTzE  
} 5zPn-1uW  
else if(nFileLength == -2) 3Qd%`k  
{  g^))  
System.err.println("File is not access!"); fv:&?gc  
} a*qc
  
else GHFYIor  
{ ,|?rt`8)Q  
for(int i=0;i<nStartPos.length;i++) w01u~"E  
{ sOm&7A?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,"f2-KC4h  
} >2mV{i&  
for(int i=0;i<nEndPos.length-1;i++) fJ;1ii~  
{ pg3h>)$/  
nEndPos = nStartPos[i+1]; \9 k3;zw  
} FO)`&s"&2  
nEndPos[nEndPos.length-1] = nFileLength; wu3p2#-Z  
} wRJ`RKJ-T  
} 9'A^n~JHF  
[_HOD^  
kyL]4:@W`  
//启动子线程 O+=C8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gp4@6HuUd  
for(int i=0;i<nStartPos.length;i++) 5UvqE_  
{ Y{<SD-ibZ$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6*s:I&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), CK8!7=>}^  
nStartPos,nEndPos,i); @O8X )  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V eLGxc  
fileSplitterFetch.start(); tJpK/"R'  
}
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ddEV@2F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); hs<OzM  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0F<$Zbe2B  
nEndPos = " + nFileLength); LzD,]{CC5  
// fileSplitterFetch[nPos.length-1].start(); Bh7dAV(  
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u2cDSRrqT  
//等待子线程结束 Ub`vf4EB  
//int count = 0; w~>tpkUB  
//是否结束while循环 c"pu"t@/Z  
boolean breakWhile = false; gb/<(I )  
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k; n
ed  
while(!bStop) #NWS)^&1b  
{ qsdgG1<  
write_nPos(); |)%;B%  
Utility.sleep(500); V(0V$&qipc  
breakWhile = true; N^zFKDJG  
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for(int i=0;i<nStartPos.length;i++) lMe+.P|  
{ S^nI=H
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if(!fileSplitterFetch.bDownOver) >~})O&t  
{ Ly]J-BTe  
breakWhile = false; 0lS=-am  
break; Nq#B4Zx  
} {tUxRX  
} =$#=w?~%  
if(breakWhile) rVB\\  
break; fy={  
.DHQJ|J-1  
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//count++; y':65N
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//if(count>4) P9qZjBS  
// siteStop(); w-LaSJ(T  
} T}K@ykT  
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System.err.println("文件下载结束！"); CwwZ~2  
} Vj6w7hz  
catch(Exception e){e.printStackTrace ();} B4x@{rtER  
} om8`^P/b  
+Os9}uKf  
&)!4rABn  
//获得文件长度 v>sjS3  
public long getFileSize() oq2-)F2/  
{ Dmr3r[  
int nFileLength = -1; l{hO"fzy  
try{ =L*-2cE6#  
URL url = new URL(siteInfoBean.getSSiteURL()); }B&+KO)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f s2}a  
httpConnection.setRequestProperty("User-Agent","NetFox"); NV`=T?1[5  
r>J%Eu/O  
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int responseCode=httpConnection.getResponseCode(); ;!)gjiapw  
if(responseCode>=400) G|qsJ  
{ BB.120v&N  
processErrorCode(responseCode); [H{2<!  
return -2; //-2 represent access is error \Yr&vX/[p  
} _eUd RL>  
|J:m{  
r)oR`\7  
String sHeader;  BF /4  
-V=,x3Zew  
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for(int i=1;;i++) k<y~n*{_  
{ p:3 V-$4X  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4VHX4A}CgA  
//Utility.log(in.readLine()); b?k6-r$j  
sHeader=httpConnection.getHeaderFieldKey(i); eHUb4,%P  
if(sHeader!=null) dUkZ_<5''  
{ 7
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if(sHeader.equals("Content-Length")) 15R:m:T  
{ [FeN(8hGS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Bs^p!4=  
break; ICzcV };$  
} UVgDm&FF  
} R/l/GNm  
else #BX}j&h_  
break; *.!5327  
} o&Y R\BI/  
} 34 I Cn~  
catch(IOException e){e.printStackTrace ();} C5~ +"#B  
catch(Exception e){e.printStackTrace ();} A\|:hzu+  
?~/_&=NSx  
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Utility.log(nFileLength); 5Vlm?mPU  
L | #"Yn  
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return nFileLength; 90gKGyxF  
} "s7}eWM*a  
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//保存下载信息（文件指针位置） eOJ_L]y-  
private void write_nPos() T2 /u7<D-  
{ /@0  
try{ <"nF`'olV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (>`S{L C>s  
output.writeInt(nStartPos.length); ]s`cn}d  
for(int i=0;i<nStartPos.length;i++) lhB;jE  
{ + De-U.  
// output.writeLong(nPos); 1l\.>H\E  
output.writeLong(fileSplitterFetch.nStartPos); TmEh$M  
output.writeLong(fileSplitterFetch.nEndPos); 7x.] 9J  
} UD_8#DO{m1  
output.close(); $LOf2kn  
} g|5cO3m0'  
catch(IOException e){e.printStackTrace ();} /`g~lww2O  
catch(Exception e){e.printStackTrace ();} /~P4<1  
} =Q4Wr0y><]  
f!J?n]  
CQ'4 ".7  
//读取保存的下载信息（文件指针位置） 0r]-Ltvl?}  
private void read_nPos() s"(F({J  
{ D'Uv7Mis  
try{ Z._%T$8aJv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `/9&o;qM   
int nCount = input.readInt(); 4v.i!U# {  
nStartPos = new long[nCount]; +HoCG;C{  
nEndPos = new long[nCount]; bM"d$tl$?'  
for(int i=0;i<nStartPos.length;i++) =:m6ge@C&H  
{ ai;-_M+$  
nStartPos = input.readLong(); 3q.HZfN~  
nEndPos = input.readLong(); Y/qs\c+  
} \{ff7_mLo  
input.close(); :xC1Ka%~  
} l|fb;Giq=D  
catch(IOException e){e.printStackTrace ();} _7,4C?  
catch(Exception e){e.printStackTrace ();} ,{BF`5bn|  
} S(G&{KG  
-"}nm!j /5  
2cko GafG{  
private void processErrorCode(int nErrorCode) x{1S!A^  
{ tW%!|T5/  
System.err.println("Error Code : " + nErrorCode); M)CQ|P  
} (*Q8!"D^6  
a 9Kws[  
?F9c6$|  
//停止文件下载 Z=^~]Mfa  
public void siteStop() r(I&`kF<  
{ y(Tb=:  
bStop = true; Em/? 4&
 
for(int i=0;i<nStartPos.length;i++) p`}G"DM  
fileSplitterFetch.splitterStop(); .ViOf){U\  
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} Mi7LyIu  
} 2]+f<Z[/  
//负责部分文件的抓取 !~te&ccPE  
**FileSplitterFetch.java .{"wliC2  
*/ E*VOyH2[  
package NetFox; `$ZBIe/u  
h4=7{0[  
h:4F
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import java.io.*; wPr!.:MF  
import java.net.*; 5N$O  
4td9=dNA+l  
~U1M-<IX  
public class FileSplitterFetch extends Thread { i(0%cNP7  
7a4h7/  
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String sURL; //File URL 8-FW'bA  
long nStartPos; //File Snippet Start Position Vs, &  
long nEndPos; //File Snippet End Position Ev,b5KelD  
int nThreadID; //Thread's ID 5KL??ao-  
boolean bDownOver = false; //Downing is over 7rIEpN>*  
boolean bStop = false; //Stop identical #F ;@Qi3z  
FileAccessI fileAccessI = null; //File Access interface j:[#eC  
AV;x'H7G  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException InB'Ag"  
{ $TFWum9wO  
this.sURL = sURL; imZ"4HnPP  
this.nStartPos = nStart; 0w?G&jjNtM  
this.nEndPos = nEnd; kNv/L$oG  
nThreadID = id; zUz j F  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %dq|)r  
} *q0vp^?  
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public void run() U_@Dn[/:  
{ P5o

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while(nStartPos < nEndPos && !bStop) 2t:CK  
{ aThvq%;  
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try{ Z1R{'@Y0Z  
URL url = new URL(sURL); aa/_:V@$~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,W5!=\Gg(  
httpConnection.setRequestProperty("User-Agent","NetFox"); z;Dc#SZnO(  
String sProperty = "bytes="+nStartPos+"-"; )q>q
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httpConnection.setRequestProperty("RANGE",sProperty); .Tc?PmN  
Utility.log(sProperty); Q =4~uz|  
-5MQ/ujQ  
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InputStream input = httpConnection.getInputStream(); bs?&;R.5  
//logResponseHead(httpConnection); Sv[$.^mb  
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}/}eZCa
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byte[] b = new byte[1024]; y:
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int nRead;  u'qc=
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) jl,
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{ mLH,6rO9  
nStartPos += fileAccessI.write(b,0,nRead); x1`zD*{  
//if(nThreadID == 1) E\*M4n\!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TQ25"bWi  
} 0EBHRY_F  
eD0|6P;Ei  
8eD/9PD=F  
Utility.log("Thread " + nThreadID + " is over!"); 1|oE3  
bDownOver = true; -k,?cEjCs  
//nPos = fileAccessI.write (b,0,nRead); e+Sq&H!@  
} p%-m"u  
catch(Exception e){e.printStackTrace ();} TJz} 8-#t  
} $(&+NJ$U$  
} +"JQ5~7  
8W}rSv+  
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//打印回应的头信息 5IFc"  
public void logResponseHead(HttpURLConnection con) z?.XVk-  
{ -e_B  
for(int i=1;;i++) /R[PsB  
{ EL;OYW(  
String header=con.getHeaderFieldKey(i); \Vl)q>K_h  
if(header!=null) 17yg ~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ew*;mQd  
Utility.log(header+" : "+con.getHeaderField(header)); DUyUA'*4n|  
else n[  
break; >o!5)\F  
} NU.YL1  
} o;'-^ LJ  
ad`=A V]  
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public void splitterStop() |#x]/AXa0/  
{ # &Z1d(!  
bStop = true; A5%cgr
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}
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xHWD1>  
} Tu-I".d+  
Wo<kKkx2  
]vq=~x  
/* '2v$xOh!y  
**FileAccess.java (V#*}eGy  
*//文件访问(定位，写) #An_RU6h  
package NetFox; \\$wg   
import java.io.*; K"g`,G6S  
vKTCS  
>(eR0.x  
public class FileAccessI implements Serializable{ [_zoJ  
VpWpC&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V;1i/{  
RandomAccessFile oSavedFile;  4B'-tV  
long nPos; =xRxr@  
?oQAxb&  
[OQ+&\  
public FileAccessI() throws IOException mM-7 jz  
{ 3Qu Ft~@@  
this("",0); jn#Ok@tZ  
} n/Dk~Q)  
4nGr?%>  
zH1ChgF=}  
public FileAccessI(String sName,long nPos) throws IOException WZ^u%Z  
{ nIv/B/>pZ  
oSavedFile = new RandomAccessFile(sName,"rw"); F/0x`l  
this.nPos = nPos; ]hlYmT  
oSavedFile.seek(nPos); }R)A%FKi@  
} 0j2M< W#  
s]i<D9h  
X.JPM{]
  
public synchronized int write(byte[] b,int nStart,int nLen) 8M7pc{  
{ - xQJY)  
int n = -1; O%rt7qV"g2  
try{ ~A-VgBbU>_  
oSavedFile.write(b,nStart,nLen); ~+Ows  
n = nLen; eLyaTOZadu  
} T``~YoIdz  
catch(IOException e) -mqTlXM  
{ E]%&)3O[  
e.printStackTrace (); fg~9{1B
 
} `zMR?F`  
D8wZC'7  
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return n; #{suH7  
} Ar1X mHq  
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} L6"?p-:@'  
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{ZD'l5jU  
/* vm`\0VGSW  
**SiteInfoBean.java E>w|i  
*/ eVujur$P  
package NetFox;
`#>JRQ=  
\>(S?)6  
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h  
public class SiteInfoBean { 0O7VM)[  
S9@)4|3C|p  
h,)UB1  
private String sSiteURL; //Site's URL !UW{xHu  
private String sFilePath; //Saved File's Path 6yPh0n  
private String sFileName; //Saved File's Name WU<C7  
private int nSplitter; //Count of Splited Downloading File j#JE4(&  
tCirdwmg  
DF~{i{  
public SiteInfoBean() $sBje*;  
{//nSplitter的缺省值为5 yZ57uz  
//default value of nSplitter is 5 /2AeJH\-  
this("","","",5); Q>[GD(8k  
}  TrmU  
O7GJg;>?  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {_1zIt|  
{ rH5'+x K  
sSiteURL= sURL; CHNIL^B  
sFilePath = sPath; L$<(HQQJ8  
sFileName = sName; |!?`KO{  
this.nSplitter = nSpiltter; |4A938'4j  
ck\gazo~q  
sH{4.tw  
} 34Z$a{ w  
_^cFdP)8|  
6o^sQ(]  
public String getSSiteURL() osW"b"_f  
{ agMI$  
return sSiteURL; 3rQ;}<*M  
} k4Ub+F  
?q+^U>wy&  
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public void setSSiteURL(String value) n8vteGQ  
{ SY
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sSiteURL = value; /|z_z%=  
} nPo YjQi  
E< Ini'od[  
Ve\=By-a|  
public String getSFilePath() _4h[q4Z  
{ )k'4]=d <  
return sFilePath;
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} J|GEt@o3  
NgPY/R>  
]^ "BLbDZ@  
public void setSFilePath(String value) -Rz%<`  
{ 5/"&C-t  
sFilePath = value; cl3Dwrf?  
} >Lrud{  
Y<oDv`aZ0  
q%xq\L.  
public String getSFileName() CH3bpZv  
{ [_SV$Jz  
return sFileName; tyyfMA?'L;  
} U6Ws#e  
#_}r)q  
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public void setSFileName(String value) Da8{==  
{ ~*,e&I  
sFileName = value; "T,^>xD  
} |<Gq^3 2  
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,  
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public int getNSplitter() G'qGsKf\  
{ a]mPc^h  
return nSplitter; ;'g.%  
} R" '=^  
:k*3?*'K  
dN)!B!*aI  
public void setNSplitter(int nCount) .8K ~ h  
{ ~\~K
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nSplitter = nCount; 1}"PLq(  
} x%\m/_5w%  
} Kgw_c:/'  
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]&l%L4Z  
/* C-
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**Utility.java 4RXF.kJ3=  
*/ 6EeK5XLf,  
package NetFox; tQ > IJ  
FaUc"J  
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public class Utility { ;x=r.3OQy  
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?
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public Utility() $NG|z0  
{ tf+5@Zf]4  
n:P5m9T  
jLLZZPBK  
} M~/R1\'&j  
,\cO>y@  
//线程睡眠 lq%6~va  
public static void sleep(int nSecond) gvx {;e  
{ D+:}D*_&  
try{ t/HUG#W{  
Thread.sleep(nSecond); %ymM#5A  
} DoYzTSWx  
catch(Exception e) LG qg0(  
{ Mkc|uiT   
e.printStackTrace (); D>~S-]  
} \X?GzQkr  
} ^.f`6 6
/  
^%:syg_RM[  
//日志 ==z,vxr  
public static void log(String sMsg) Z$'483<  
{ )(&WhZc Z  
System.err.println(sMsg); d].(x)|st  
} 0,x<@.pW  
Ea7LPHE#  
4xE [S  
public static void log(int sMsg) |GQFNrNx  
{ *`HE$k!  
System.err.println(sMsg); 4Nx]*\\  
} [x.DwU%S  
} ~Uet)y<  
/>i~No#Xm  
xNaDzu"  
/* h5.>};"@'  
**TestMethod.java JZS#Q\JN  
*/ %`~?w'  
package NetFox; HAi'0%"  
C"We>
!  
1ukCH\YgU  
public class TestMethod { lVmm`q
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u9 yXHf  
XZk?aik}`  
public TestMethod() JTxHM?/G  
{ ///xx/weblogic60b2_win.exe N){/#3  
try{ Gpauy=4f  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FojsI<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k^ZcgHHgb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); uk(|c-_]~c  
fileFetch.start(); B[I a8t  
} gZ^NdDBO  
catch(Exception e){e.printStackTrace ();} pxs#OP  
@]EJbiGv  
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} *&\fBi]  
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JlF$|y,gV,  
public static void main(String[] args) qrj:H4#VB  
{ Ak\w)!?s  
new TestMethod(); kh'R/Dt  
} xfE:r:  
} $ 4& )  
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