http断点续传简单实现（java)

/* Ox&G  [  
**SiteFileFetch.java 1JfZstT  
*/ ed}#S~4q  
package NetFox; ,7c Rd}1Y  
import java.io.*; ;RX u}pd  
import java.net.*; uOJqj{k_."  
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public class SiteFileFetch extends Thread { Up'#OkTx  
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SiteInfoBean siteInfoBean = null; //文件信息Bean KX
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long[] nStartPos; //开始位置 MuQ)F-GSUu  
long[] nEndPos; //结束位置 9A} *  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *|Er;Thw  
long nFileLength; //文件长度 L YF|  
boolean bFirst = true; //是否第一次取文件 'ScvteQ  
boolean bStop = false; //停止标志 z'& fEsjy  
File tmpFile; //文件下载的临时信息 3^~J;U!3  
DataOutputStream output; //输出到文件的输出流 htR.p7&Tn  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 0]iaNR %  
public SiteFileFetch(SiteInfoBean bean) throws IOException /*,_\ ;  
{ <?5|(Q"@:  
siteInfoBean = bean; p^|l ',e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4fC:8\A  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;-kDJi  
if(tmpFile.exists ()) !Kg']4  
{ B6k<#-HAT  
bFirst = false; -Z$u[L [c  
read_nPos(); Z%B6J>;uM  
} a~$Y;C_#<  
else U>f'j;5  
{ }0Ns&6)xG  
nStartPos = new long[bean.getNSplitter()]; XgHJ Oqt  
nEndPos = new long[bean.getNSplitter()]; qz>R"pj0g  
} ;s/<wx-C  
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} , i5_4  
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public void run() c Pf_B=  
{ ;x/eb g  
//获得文件长度 ?e<2'\5v  
//分割文件 Fds 11 /c7  
//实例FileSplitterFetch 2]]v|Z2M4  
//启动FileSplitterFetch线程 6_bL<:xtY  
//等待子线程返回 ~E7IU<B  
try{ R;c9)>8L  
if(bFirst) UgC65O2  
{ 96(Mu% l  
nFileLength = getFileSize(); Oti*"dV\::  
if(nFileLength == -1) l\*9rs:!  
{ ]$[sfPKA  
System.err.println("File Length is not known!"); "a8E
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} K%? g6j  
else if(nFileLength == -2) jfY7ich  
{ Ey|_e3Lf[  
System.err.println("File is not access!"); r@{TN6U  
} !ka* rd  
else
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{ 3uqhYT;  
for(int i=0;i<nStartPos.length;i++) Ww2@!ng  
{ Lz'VQO1U=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *
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} 0B]q /G(  
for(int i=0;i<nEndPos.length-1;i++) rTIu'  
{ 6(f'P_*  
nEndPos = nStartPos[i+1]; Yg^ &4ZF  
} Y#ZgrziYM  
nEndPos[nEndPos.length-1] = nFileLength; xf]K  
} ]$@D=g,r  
} w#|L8VAh  
`.W2t5Y  
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//启动子线程 +O.-o/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2M-[x"\1/  
for(int i=0;i<nStartPos.length;i++) P9 <U+\z  
{ 64zOEjra  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5*pzL0,Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), AAevN3a#nI  
nStartPos,nEndPos,i); !w
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VI&x1C  
fileSplitterFetch.start(); FvxM  
} _s=H|#l  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _qxI9Q}<"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,twx4r^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", XVYFyza;  
nEndPos = " + nFileLength); @Nek;xJ  
// fileSplitterFetch[nPos.length-1].start(); W&?Qs=@  
 <OMwi9  
$oK&k
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//等待子线程结束 JL1ajlm~  
//int count = 0; WEimJrAn  
//是否结束while循环 ^Co$X+  
boolean breakWhile = false; "?I#!t%'  
}X&rJV  
<-umeY"n>  
while(!bStop) Wh)D_  
{ YX0ysE*V:&  
write_nPos(); ;.A}c)b  
Utility.sleep(500); AG N/kx  
breakWhile = true; i+*!"/De  
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for(int i=0;i<nStartPos.length;i++) E#B-JLMGl  
{ ?l0eU@rwQ  
if(!fileSplitterFetch.bDownOver) Lnr9*dm6q  
{ Iux3f+H  
breakWhile = false; J7`mEL>?  
break; +xFn~b/  
} *;o%*:  
} $.SBW=^V  
if(breakWhile) \#{PV\x:Nn  
break; #).$o~1ht!  
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HZyA\FS  
//count++; oN7SmP_  
//if(count>4) 2B ]q1>a!  
// siteStop(); oJ74Mra  
} 3
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r )F;8
(  
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System.err.println("文件下载结束！"); j[G`p^ul  
} }aZuCe_  
catch(Exception e){e.printStackTrace ();} k?+ 7%A]  
} l|P"^;*zq  
Yj/afn(Jt  
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//获得文件长度 j/O~8o&  
public long getFileSize() [FO4x`  
{ c|&3e84U  
int nFileLength = -1; 6hxZ5&;(*  
try{ a+w2cN'  
URL url = new URL(siteInfoBean.getSSiteURL()); v/+ <YU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Re$h6sh  
httpConnection.setRequestProperty("User-Agent","NetFox"); G;Li!H  
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int responseCode=httpConnection.getResponseCode(); ge~@}&#iO@  
if(responseCode>=400) *]$B 9zVs!  
{ DXs an  
processErrorCode(responseCode); :<QknU}dwy  
return -2; //-2 represent access is error d*@T30  
} e97G]XLR  
<xI<^r'C9e  
X?5{2ulrI  
String sHeader; Hn|W3U  
)4yP(6|lx  
8dGsV5"*  
for(int i=1;;i++) BI1M(d#1L"  
{ ,>;21\D  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); GWA"!~Hu  
//Utility.log(in.readLine()); IDohv[#  
sHeader=httpConnection.getHeaderFieldKey(i); *WwM"NFHDd  
if(sHeader!=null) W0qR?jc  
{ rq+_[!
 
if(sHeader.equals("Content-Length")) xe@1H\7:  
{ 5'AP:3Gf"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); nBh+UT}  
break; 4Uy%wB  
} =)a24PDG  
} #[+# bw_6  
else ]I?.1X5d0  
break; uO%0rKW  
} 2|nm> 4  
} ^P)f]GQx  
catch(IOException e){e.printStackTrace ();} !nvwRQ  
catch(Exception e){e.printStackTrace ();} FY1iY/\Cn  
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Utility.log(nFileLength); mUYRioNj  
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return nFileLength; 66yw[,Y  
} -ss= c
#  
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acd[rjeT  
//保存下载信息（文件指针位置） A;oHji#*  
private void write_nPos() ci0A!wWD  
{ ['d9sEv.  
try{ |Y9>kXMl  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i'IT,jz!  
output.writeInt(nStartPos.length); slQn  
for(int i=0;i<nStartPos.length;i++) c_J9CKqc  
{ u`pTFy  
// output.writeLong(nPos); VY?9|};f  
output.writeLong(fileSplitterFetch.nStartPos); c+Q'4E0|  
output.writeLong(fileSplitterFetch.nEndPos); ++cS^ Lo  
} HW@wia  
output.close(); eg0_ <  
} iq#{*:1  
catch(IOException e){e.printStackTrace ();} "+HJ/8Dd1  
catch(Exception e){e.printStackTrace ();} 70'OS:J=\  
} B*,6;lCjX  
AO#9XDEM  
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//读取保存的下载信息（文件指针位置） 1"h"(dA  
private void read_nPos() Jw)JV~/0  
{ q m3\)9C  
try{ b1&tk~D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fvu{(Tb  
int nCount = input.readInt(); ]Q^)9uE\D  
nStartPos = new long[nCount]; !/FRL<mp  
nEndPos = new long[nCount]; 7=^{~5#  
for(int i=0;i<nStartPos.length;i++) U3(+8}Q  
{ =[B\50]  
nStartPos = input.readLong(); I
/E9:  
nEndPos = input.readLong(); .u-a+ac<  
} f ,F X# _4  
input.close(); mZ)>^.N6  
} }EK{UM9y  
catch(IOException e){e.printStackTrace ();} <,i4Ua  
catch(Exception e){e.printStackTrace ();} 5'2kP{;  
} KC/O EJ`  
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private void processErrorCode(int nErrorCode) PR:k--)D  
{ bo0U  
System.err.println("Error Code : " + nErrorCode); Pv -4psdw  
} r!:yUPv  
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u]p21)m$x  
//停止文件下载 d:kB Zrq  
public void siteStop() 6o't3Peh  
{ U4D7@KY +m  
bStop = true; rH@Rh}#yp  
for(int i=0;i<nStartPos.length;i++) \8vP"Kr  
fileSplitterFetch.splitterStop(); a4Q@sn;]  
}(EH5jZ'  
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} /jv/qk3i  
} 5.rAxdP  
//负责部分文件的抓取 $dC`keQM>9  
**FileSplitterFetch.java Sd7jd?#9'  
*/ =LW!$p  
package NetFox; N' hT
  
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import java.io.*; .j}]J:{%  
import java.net.*; ORM>|&  
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@G5T8qwN  
public class FileSplitterFetch extends Thread { VjQ&A#   
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String sURL; //File URL q*I*B1p[m  
long nStartPos; //File Snippet Start Position UU=]lWib  
long nEndPos; //File Snippet End Position 0eY!Z._^  
int nThreadID; //Thread's ID
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boolean bDownOver = false; //Downing is over j.E=WLKV*  
boolean bStop = false; //Stop identical #GzALF97  
FileAccessI fileAccessI = null; //File Access interface )Sn0Y B  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8Qvs\TY  
{ `v*HH}aDO  
this.sURL = sURL; 0 QTI;3  
this.nStartPos = nStart; Y
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this.nEndPos = nEnd; kx,.)qKk  
nThreadID = id; =p5D

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fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]#:WL)@  
} mxNd_{n  
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`/O`%6,f1!  
public void run() 6tKrR{3#A  
{ QLqtE;;)JK  
while(nStartPos < nEndPos && !bStop) S<Dbv?  
{ ;V,
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try{ Hw \of  
URL url = new URL(sURL); $/wm k7T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e]4$H.dP  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2<D| {  
String sProperty = "bytes="+nStartPos+"-"; X^\D"fmE.  
httpConnection.setRequestProperty("RANGE",sProperty); P6+ B!pY  
Utility.log(sProperty); nI:M!j5s`  
5(>=};r+  
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InputStream input = httpConnection.getInputStream(); gAAC>{Wh  
//logResponseHead(httpConnection); D<WnPLA$g  
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byte[] b = new byte[1024]; Pn,I^Ej.  
int nRead; <KMCNCU\+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *b{IWOSe^  
{ \<{a=@_k9  
nStartPos += fileAccessI.write(b,0,nRead); .psb#4  
//if(nThreadID == 1) ACRuDY  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ht[$s40P  
} &'uP?r9c$  
;cMQ0e  
Oeh A3$|#  
Utility.log("Thread " + nThreadID + " is over!"); 7FC!^)x1  
bDownOver = true; ,Lig6Z`  
//nPos = fileAccessI.write (b,0,nRead); \.LjA_  
} "J(M.Y  
catch(Exception e){e.printStackTrace ();} J!:BCjRdw  
}  ?eS;Yc  
} YBt=8`r  
64B.7S88  
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//打印回应的头信息 8~Cmn%  
public void logResponseHead(HttpURLConnection con) u)@:V)z  
{ $qD\ku;'  
for(int i=1;;i++) m23"xnRB  
{ [qc1 V%g  
String header=con.getHeaderFieldKey(i); ~F"S]  
if(header!=null) j iKHx_9P  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o/Ismg-p  
Utility.log(header+" : "+con.getHeaderField(header)); 'z|Da&d P  
else q`xc h[H  
break; &5W;E+Pub  
} T}fo  
} &gCGc?/R#  
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public void splitterStop() O#)1zD}  
{ AjK5x@\  
bStop = true; Ohm{m^VD"  
} | 6{JINW  
{H)7K.hQN  
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} +>PsQ^^x  
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/* '{ <RX  
**FileAccess.java x?S86,RW  
*//文件访问(定位，写) FX!KX/OE)  
package NetFox; ~.T|n =  
import java.io.*; w)7y{ya$  
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public class FileAccessI implements Serializable{ \5a.JfF  
UFj H8jSBx  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 )Rn\6ka  
RandomAccessFile oSavedFile; gX"-3w  
long nPos; \c2x udU  
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public FileAccessI() throws IOException 
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{ }u8(7  
this("",0); uWJJ\  
} 6{6hz8  
#B\s'j[A"  
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public FileAccessI(String sName,long nPos) throws IOException 8dR `T}  
{ 8&JB_%Gb  
oSavedFile = new RandomAccessFile(sName,"rw"); y i$+rPF1  
this.nPos = nPos; |enLv12Gm  
oSavedFile.seek(nPos); w"{DLN[Qw  
} Va )W[I  
%`i*SF(gV  
8\s#law  
public synchronized int write(byte[] b,int nStart,int nLen) SJ]6_4=y*  
{ ei-\t qY_  
int n = -1; !q&Td  
try{ .57p4{  
oSavedFile.write(b,nStart,nLen); )K[\j?
 
n = nLen; iqlb,8  
} Bz
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catch(IOException e) 7(}'
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{ Y
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e.printStackTrace (); PhyIea  
} 35l%iaj]G5  
/ZyMD(_J  
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return n; DQGrXMpV0  
} FO*Gc Z  
}||u{[  
{&+M.Xn  
} 0`"oR3JY  
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M P8Sd1_=  
/* Hs)Cf)8u  
**SiteInfoBean.java ?z>J7 }w*=  
*/ DKf(igw  
package NetFox; j""ZFh04  
$ 64up!  
*Z#OfB4}  
public class SiteInfoBean { m""+$  
uXc;!*  
*47/BLys<  
private String sSiteURL; //Site's URL GQYR`;>  
private String sFilePath; //Saved File's Path h^g0|p5  
private String sFileName; //Saved File's Name j&X&&=   
private int nSplitter; //Count of Splited Downloading File <&m50pq  
jfG of*  
{wC*61@1  
public SiteInfoBean() OKh0m_ )7  
{//nSplitter的缺省值为5 +ydd"`  
//default value of nSplitter is 5 Xqw}O2QQ1  
this("","","",5); ?9t4>xKn  
} 1 tOslP@  
lU doMm  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _tHhS@  
{ Mz&/.A  
sSiteURL= sURL; l:'#pZ4T  
sFilePath = sPath; 0!,uo\`  
sFileName = sName; =.z;:0]'n  
this.nSplitter = nSpiltter; Wxj_DTi[1"  
bL xZ5C7t  
aVu!Qk=Z/  
} SE\?8cs]-  
d3:GmB .  
,!_6X9N-h  
public String getSSiteURL() #][i!9$  
{ YVccO~!8  
return sSiteURL; !~|-CF0z=  
} S L 5k^|  
G:1d6[Q5{  
": vGs_$  
public void setSSiteURL(String value) y@!M<#SEzG  
{ O&<p 8
 
sSiteURL = value; f|,Kh1{e  
} 2]vTedSOl  
%)
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HaVhdv3L  
public String getSFilePath() jMn,N9Mf  
{ yMWh#[phH  
return sFilePath; }`gOfj)?i  
} KhND pwO"  
K.xABKPVc  
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public void setSFilePath(String value) |OJWQU![by  
{ kQmkS^R  
sFilePath = value; &Pb:P?I  
} J$51z  
N`Q.u-'  
8</wQ6&
|  
public String getSFileName() =dPokLXn  
{ 0Ncpi=6  
return sFileName; o#p%IGG`  
} V~/G,3:0y%  
VaD+:b4  
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public void setSFileName(String value) '?Dxe B  
{ 3tZIL  
sFileName = value; CFh9@
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} _e@8E6#ce  
#VrIU8Q7'  
I6 ?(@,  
public int getNSplitter() }T4|Kyu?  
{ /:F^*
]  
return nSplitter; M/6Z,oOU  
} 6 ]x?2P%  
.yy-jf/  
w*6b%h%ww  
public void setNSplitter(int nCount) 74M9z  
{ l$/pp  
nSplitter = nCount; $ztsbV}  
} v\,N"X(,  
} :C>7HEh-2_  
 ;v.[aq  
i3,.E]/wX@  
/* sm-[=d%@L  
**Utility.java 83c2y;|8  
*/ QP%_2m>yhl  
package NetFox; r+bGZ  
-~{Z*1`,  
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public class Utility { ."+lij=56  
~gpxK{  
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public Utility() 
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{ yus3GqPI  
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n- 2X?<_Z  
} >IIq_6Z#  
To*+Z3Wd  
//线程睡眠 S[K5ofV  
public static void sleep(int nSecond) p{L;)WTI  
{ &q>8D'  
try{ 6=;:[
 
Thread.sleep(nSecond); W,@F!8  
} <(KCiM=E$  
catch(Exception e) -iiX!@  
{ _uO$=4Sd  
e.printStackTrace (); ,m<YSMKX  
} 9InP2u\&:  
} >T[/V3Z~K  

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//日志 Xd+H()nR  
public static void log(String sMsg) 2{h2]F  
{  tA#$q;S  
System.err.println(sMsg); x/O;8^b  
} SxYz)aF~  
i]c{(gd`  
Rv&"h_"t  
public static void log(int sMsg) jg?UwR&  
{ 4

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System.err.println(sMsg); iI<c  
} .u)KP*_  
} |Ml~Pmpp  
r)|~Rs!y,  
LWM<[8wJ4  
/* ya&=UoI  
**TestMethod.java WkuCnT  
*/ NIQ}A-b  
package NetFox; XKTDBaON  
DKS1Sm6d0  
3 ZOD2:(  
public class TestMethod { A1p~K*[[  
%f'pAc|#  
f![] :L  
public TestMethod() \>5sW8P]H`  
{ ///xx/weblogic60b2_win.exe ;$
iT]S  
try{ :i!fPNn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'mZv5?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^# $IoW  
SiteFileFetch fileFetch = new SiteFileFetch(bean); []A9j?_w  
fileFetch.start(); ]ltCJq  
} :=hL}(~]  
catch(Exception e){e.printStackTrace ();} Yd3lL:M  
"zq'nV=  
)3CM9P'0  
} 5&8BO1V.  
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k)3N0]q6  
public static void main(String[] args) :\~>7VFg  
{ =wX;OK|U(^  
new TestMethod(); zh2<!MH  
} f$>_>E  
} q(qm3OxYo  
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