http断点续传简单实现（java)

/* 'HvJ]}p  
**SiteFileFetch.java lt#3&@<v  
*/ #6nuiSF  
package NetFox; }Hb_8P  
import java.io.*; sDyt3xN  
import java.net.*; +xBM\Dz8  
!$fF3^8-  
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public class SiteFileFetch extends Thread { )D ':bWP  
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SiteInfoBean siteInfoBean = null; //文件信息Bean HvW6=d(#  
long[] nStartPos; //开始位置 FyRr/0C>  
long[] nEndPos; //结束位置 J%8hf%!ud  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'PdUSv|lH  
long nFileLength; //文件长度 d 2z!i^:  
boolean bFirst = true; //是否第一次取文件 r%%<   
boolean bStop = false; //停止标志 qino:_g  
File tmpFile; //文件下载的临时信息 ?wMS[Kj  
DataOutputStream output; //输出到文件的输出流 $GIup5  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BV]$= e'  
public SiteFileFetch(SiteInfoBean bean) throws IOException wQ\bGBks  
{ =[`gfw  
siteInfoBean = bean; ;>jOB>b{h  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); XF9
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); UsdUMt!u  
if(tmpFile.exists ()) l"9$lF}
 
{ y(jd$GM|  
bFirst = false; iU4Z9z!  
read_nPos(); : W0;U  
} '! ~s=  
else ilFS9A3P  
{ tj[-|h  
nStartPos = new long[bean.getNSplitter()]; ,w7ZsI4:[  
nEndPos = new long[bean.getNSplitter()]; !6`&0eY  
} H;RgYu2J  
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} M.KXDD#O  
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 P'oY+#  
public void run() opqf)C  
{ r+}<]?aT>-  
//获得文件长度 da5fKK/s  
//分割文件 fx/If  
//实例FileSplitterFetch ^Rmrre`uU  
//启动FileSplitterFetch线程 N1X;&qZDd  
//等待子线程返回 z2OXCZ*/  
try{
>~@ABLp6  
if(bFirst) +<f!#4T  
{ p *GAs C  
nFileLength = getFileSize(); q:G3y[ P  
if(nFileLength == -1) +!"7=?}  
{ g (V_&Y  
System.err.println("File Length is not known!"); 9,0}}3J  
} 5!7vD|6  
else if(nFileLength == -2) }xytV5a^  
{ 61`tQFx,  
System.err.println("File is not access!"); "S3U]zw0_  
} LH>h]OTQF  
else !24g_R[3"  
{ 
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for(int i=0;i<nStartPos.length;i++) A]m_&A#  
{ M[KYt"v  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [I%'\CI;  
} ' g Fewo  
for(int i=0;i<nEndPos.length-1;i++) {fu[&@XV  
{ ufS0UD8%H  
nEndPos = nStartPos[i+1]; h
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} n16TQe"8  
nEndPos[nEndPos.length-1] = nFileLength; *ZF:LOnU  
} s:Z1 ZAxv  
} mp17d$R-  
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//启动子线程 No(S#,vJ;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5 OF*PBZ  
for(int i=0;i<nStartPos.length;i++) q??N,  
{ Ox+}JB [  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ( ALsc@K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), d$v{oC}  
nStartPos,nEndPos,i); 8:}$L)[V  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3vF-SgCV  
fileSplitterFetch.start(); " {Nw K  
} S{qn^\0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "gq_^&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); L&qY709  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", T2i\S9X  
nEndPos = " + nFileLength); [`=:uUf3  
// fileSplitterFetch[nPos.length-1].start(); $q$\  
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//等待子线程结束 Zz56=ZX*_  
//int count = 0; 0p!N'7N  
//是否结束while循环 {;?bC'  
boolean breakWhile = false; v{TISgZ  
o@:u:n+.  
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while(!bStop) f`_6X~
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{ ]\oE}7K%r  
write_nPos(); f{f|frs  
Utility.sleep(500); "aeKrMgc6V  
breakWhile = true; mS >I#?  
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v$bR&bCT  
for(int i=0;i<nStartPos.length;i++) u
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{ EO\@#",a  
if(!fileSplitterFetch.bDownOver) Fs1ms)  
{ Gm'Ch}E  
breakWhile = false; 9Q*zf@w  
break; \}NZ]l  
} R,[+9U|4V  
} yy$7{9!  
if(breakWhile) ekO*(vQ~  
break; Ix'GP7-m_  
}J\KnaKo  
8:t1%O$  
//count++; i+B
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//if(count>4) !FJ_\UST0  
// siteStop(); "Yf?33UNZ  
} Qv:J#uVw?O  
m4kUA"n5  
^t
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System.err.println("文件下载结束！"); VWcR@/3  
} 1F }mlyS  
catch(Exception e){e.printStackTrace ();} E9n7P'8  
} %#b+ =J  
^
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//获得文件长度 T
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public long getFileSize() }8&L?B;90  
{ O8S"B6?$~'  
int nFileLength = -1; j8#B  
try{ >l|dLyiae  
URL url = new URL(siteInfoBean.getSSiteURL()); YfOO]{x,X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O{`r.H1',  
httpConnection.setRequestProperty("User-Agent","NetFox"); CF+:9PG  
vt-53fa|  
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int responseCode=httpConnection.getResponseCode(); F6\r"63  
if(responseCode>=400) 'aW<C>  
{ E>6:59+  
processErrorCode(responseCode); e8<[2J)P&  
return -2; //-2 represent access is error zhFk84  
} BFyVq  

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String sHeader; } ~#^FFe  
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for(int i=1;;i++) "Crm\UI6  
{ !t92_y3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bAqaf#}e  
//Utility.log(in.readLine()); iv62Fs'  
sHeader=httpConnection.getHeaderFieldKey(i); l<#*[TJ  
if(sHeader!=null) a uz2n  
{ 1u0NG)*f  
if(sHeader.equals("Content-Length")) Nm]\0m0p-  
{ fr<, LC.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -KG3_kE  
break; $di8#O*  
} S\O6B1<:  
} O<v9i4*  
else SRx `m,535  
break; 3xnu SOdh  
} |k^ *  
} 4?{e?5)  
catch(IOException e){e.printStackTrace ();} 7T3ub3\  
catch(Exception e){e.printStackTrace ();} +#!! 'XP  
5=--+8[ bV  
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Utility.log(nFileLength); ;{Kx$Yt+  
i
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return nFileLength; [1*3 kt*h  
} Fv6<Cz6L  
)gR !G]Y  
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//保存下载信息（文件指针位置） ^.9I[Umua  
private void write_nPos() YSE6PG   
{ 7!E?(3$#"  
try{ 9}2E+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Qm X(s  
output.writeInt(nStartPos.length); N yK7TKui  
for(int i=0;i<nStartPos.length;i++) s~(iB{-  
{ @gZ<!g/vza  
// output.writeLong(nPos); CS*wvn;.  
output.writeLong(fileSplitterFetch.nStartPos); p}'uCT ga  
output.writeLong(fileSplitterFetch.nEndPos); 2nRL;[L*.  
} E5<}7Pt  
output.close(); VfiMR%i}  
} NN9`jP2  
catch(IOException e){e.printStackTrace ();} H `V3oS~}  
catch(Exception e){e.printStackTrace ();} (fjAsbT  
} ]7, mo  
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//读取保存的下载信息（文件指针位置） nVC:5ie  
private void read_nPos() 1wa zJj=v  
{ hd2 X/"  
try{ N}3$1=@Y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); bVc;XZwI  
int nCount = input.readInt(); |&t 2jD(  
nStartPos = new long[nCount]; ui:  
nEndPos = new long[nCount]; \&p MF  
for(int i=0;i<nStartPos.length;i++) oiq7I@Y`x  
{ j:9kJq>mv  
nStartPos = input.readLong(); < g<Lf[n$  
nEndPos = input.readLong(); |QvG;{!  
} {zc<:^r^  
input.close(); e:Zc-  
} _ s]=g  
catch(IOException e){e.printStackTrace ();} 0NB6S&lI^k  
catch(Exception e){e.printStackTrace ();} lr[a~ca\  
} w$cic  
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private void processErrorCode(int nErrorCode) Gw$sL&1m\  
{ @JWoF^U  
System.err.println("Error Code : " + nErrorCode); aNpeePF)z  
} [*j C  
6N&S3<c4JO  
;u'mSJI'  
//停止文件下载 tZ]|3wp  
public void siteStop() *JX)q  
{ lMX 2O2 o  
bStop = true; 7)IBIlV  
for(int i=0;i<nStartPos.length;i++) V6,D~7  
fileSplitterFetch.splitterStop(); tj ,*-).4%  
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} ai(<"|(  
} U/2g N H  
//负责部分文件的抓取 ]Ph~-O  
**FileSplitterFetch.java z I`'n%n=  
*/ (XJehdB0  
package NetFox; }(AUe5aw`G  
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import java.io.*; V#1_jxP)Q  
import java.net.*; BJk:h-m [  
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public class FileSplitterFetch extends Thread { 2#LcL  
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String sURL; //File URL 4@|K^nT`  
long nStartPos; //File Snippet Start Position >U^AIaW  
long nEndPos; //File Snippet End Position PG9won5_  
int nThreadID; //Thread's ID %*<k5#Yq  
boolean bDownOver = false; //Downing is over C8cB Lsa[J  
boolean bStop = false; //Stop identical {a9Z<
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FileAccessI fileAccessI = null; //File Access interface ;h_"5/#  
2](R}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qt}vM*0}V  
{ y-}lz#N  
this.sURL = sURL; *Xt#04_  
this.nStartPos = nStart; /`0*!sN*5  
this.nEndPos = nEnd; A\ze3fmV  
nThreadID = id; $Vbgfp
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 "OF
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} F8YD:   
3mZX@h@  
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public void run() 4pkc9\  
{ |Wj)kr !|  
while(nStartPos < nEndPos && !bStop) pq*b"Jku1  
{ ExI?UGT  
b,7:=-D  
8nQlmWpJ  
try{ 5?k_Q"~  
URL url = new URL(sURL); @\Sa)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |]DZc/  
httpConnection.setRequestProperty("User-Agent","NetFox"); hT^6Ifm  
String sProperty = "bytes="+nStartPos+"-"; 9#/z[!  
httpConnection.setRequestProperty("RANGE",sProperty); Kom$i<O?48  
Utility.log(sProperty); B8Jev\_  
{LJwW*?  
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InputStream input = httpConnection.getInputStream(); +f+x3OMX3  
//logResponseHead(httpConnection); KI-E=<zt  
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} e  
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byte[] b = new byte[1024]; WUGPi'x  
int nRead; g{8>2OK$c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qUx!-DMY  
{ `HgT5}  
nStartPos += fileAccessI.write(b,0,nRead); '7 6}6G%  
//if(nThreadID == 1) vC$[Zm  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5IBe;o  
} W*u Yb|0  
ov#/v\|0  
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Utility.log("Thread " + nThreadID + " is over!"); =!9+f  
bDownOver = true; {_ww1'|A  
//nPos = fileAccessI.write (b,0,nRead); so8isDC'9  
} ,/m<=`*N|  
catch(Exception e){e.printStackTrace ();} j?+FS`a!  
} T5-50nU,~  
} 4NQS'*%D  
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//打印回应的头信息 q3VE\&*^F  
public void logResponseHead(HttpURLConnection con) /o.wCy,J<  
{ MH'S,^J  
for(int i=1;;i++) ]b.@i&M  
{ C"<l}  
String header=con.getHeaderFieldKey(i); d&wg\"E  
if(header!=null) 0LrTYrlj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >VE,/?71@  
Utility.log(header+" : "+con.getHeaderField(header)); K:V_,[g
O  
else 9vmH$  
break; 68*h#&  
} I/Hwf  
} <3LyNG.  
"7JO~T+v  
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public void splitterStop() xQ* U9Wt;T  
{ ya5;C"  
bStop = true; w-AF5%gX  
} &%>l9~F'~  
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} 245(ajxHC  
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69!J'kM[  
/* eq<xO28z  
**FileAccess.java "k)( ,  
*//文件访问(定位，写) mF%>pj&b  
package NetFox; H(lq=M0~  
import java.io.*; zob^z@2  
/wljbb/s  
]~U4;  
public class FileAccessI implements Serializable{ fk5!/>X  
R KFz6t  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 % rRYT8  
RandomAccessFile oSavedFile; m_W\jz??k  
long nPos; ;? '`XB!  
XK`>#*"V  
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public FileAccessI() throws IOException (i.MxGDd  
{ ]N*q3y|)  
this("",0); ]\v'1m"  
} TF}<,aR  
!<h*\%;  
G':mc{{  
public FileAccessI(String sName,long nPos) throws IOException H\Y.l,^  
{ )p~\lM}?d  
oSavedFile = new RandomAccessFile(sName,"rw"); 7Z0 )k9*  
this.nPos = nPos; ~
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oSavedFile.seek(nPos); k v,'9z  
} >5% o9$|z  
`pn]jpW9  
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public synchronized int write(byte[] b,int nStart,int nLen) ecA
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{ g:dw%h  
int n = -1; "w*VyD  
try{ `4'v)!?  
oSavedFile.write(b,nStart,nLen); NN\% X3ri"  
n = nLen; lf4-Ci*X  
} 05gU~6AF  
catch(IOException e) pD9*WKEf*  
{ yc8iT`
 
e.printStackTrace (); (*;b\h  
}
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return n; )TP1i  
} >to NGGU=~  
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} /1zi(z   
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/* !e?=I  
**SiteInfoBean.java *TfXMN?w  
*/ 5n"b$hMF  
package NetFox; 8
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j5Vyo>  
public class SiteInfoBean { :7KcD\fCj  
\zR@FOl`q  
()6(eRGJ  
private String sSiteURL; //Site's URL {CG%$rh  
private String sFilePath; //Saved File's Path O]DZb+O"  
private String sFileName; //Saved File's Name Zgkk%3'^'  
private int nSplitter; //Count of Splited Downloading File VU J*\Sg  
p[4KN(PyK  
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public SiteInfoBean() w= |).qQ]  
{//nSplitter的缺省值为5 hD/bgquT  
//default value of nSplitter is 5 -M2c8P:.b  
this("","","",5); 0UB)FK,9  
} %"r3{Hs  

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7;:R\d6iL  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) EdlU}LU  
{ 2.{:PM4Z4  
sSiteURL= sURL; |Gx-c ,{{  
sFilePath = sPath; OCnQSkj  
sFileName = sName; kO{A]LnAH  
this.nSplitter = nSpiltter; 3,
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:aI[ lZ  
1Jg&L~Ws"  
} y2;uG2IS_g  
yDg`9q.ckm  
=e=sK'NvD  
public String getSSiteURL() 3.Z}2F]  
{ @d:TAwOI'  
return sSiteURL; #!wu}nDu  
} qPDe;$J)  
}enm#0Ha  
&<2~7?$!  
public void setSSiteURL(String value) m X{_B!j^  
{ ;9PJ K5>~  
sSiteURL = value; 87l(a,#J  
} 62TWqQ!9d  
kG@~;*;l  
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public String getSFilePath() Jz(wXp  
{ btoye \rl  
return sFilePath; Clr~:2g\  
} ?9'Ukw` g  
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public void setSFilePath(String value) ad+@2-Y  
{ P /|
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sFilePath = value; F6J,:  
} [vh&o-6  
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}iZO0C  
public String getSFileName() 2L Kpwz?  
{ L}NckL  
return sFileName; P>n}\"z4  
} {_T?0L  
C ioM!D  
:ZX#w`Y  
public void setSFileName(String value) D]X&Va  
{ 1(t{)Z<  
sFileName = value;  -i*{8t  
} l&#&}3M  
}TE4)vXs  
#~QkS_  
public int getNSplitter() xc{$=>'G  
{ m%au* 0p  
return nSplitter; LgFF+z  
} qM%l  
{WJ9!pA!lk  
x.W93e[]H  
public void setNSplitter(int nCount) ;U$Fz~rJ  
{ 4+46z|  
nSplitter = nCount; 1~rZka[s  
} R@zl?
>+  
} xNDX(_U>\  
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H{qQ8j)  
/* W Cz+  
**Utility.java ip.aM#  
*/ ${fJ]  
package NetFox; o&WKk5$  
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public class Utility { QE8;Jk-  
)2
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public Utility() P(h[QAM  
{ ^}Vx5[  
VaKBS/y"  
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} sX_6qKUH  
a(cZ]`s]*  
//线程睡眠 JSO'. [N  
public static void sleep(int nSecond) Ujb7uho  
{ luLt~A3H$  
try{ IbV 7}  
Thread.sleep(nSecond); =?
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} fu 0]BdM  
catch(Exception e) !.\-l2f  
{ 4l)Q  
e.printStackTrace (); |a!y%R=  
} \ct7~!qM  
} ;F3#AO4(  
XQW9/AzNf  
//日志 _}G1/`09#  
public static void log(String sMsg) ?VM4_dugf  
{ lxSCN6  
System.err.println(sMsg); #\DKU@|h  
} cow]qe6K  
~# ~XDcc  
BBkYc:B=SA  
public static void log(int sMsg) o]gS=iLp  
{ UB5X2uBv  
System.err.println(sMsg); uPZ<hG#K  
} 78o>UWA:  
} GJLe733o  
`)Z+]5:  
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/* )2lzPK t  
**TestMethod.java ?|}%A9  
*/ ik:fq&=  
package NetFox; )TH~Tq:  
h 7x_VO  
)wFr%wNe  
public class TestMethod { :>G3N+A)  
s01W_P.@R  

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public TestMethod() P%%[_6<%M  
{ ///xx/weblogic60b2_win.exe  8AX+s\N  
try{ Rq,ST:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); cx_.+R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); J|Af`HJ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); I[td:9+hK@  
fileFetch.start(); ICbT{Mla  
} w26x)(7  
catch(Exception e){e.printStackTrace ();} v8PH(d2{@  
~4MUac^w  
N7}Y\1-8  
} Z3j
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public static void main(String[] args) B^{87YR  
{ Po+tk5}''5  
new TestMethod(); c<T'_93  
} VlLc[eVV  
} !"dn!X  
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