http断点续传简单实现（java)

/* AK[9fxrE  
**SiteFileFetch.java <ygkK5#q  
*/ L:B&`,E  
package NetFox; fNB*o={r|  
import java.io.*; k92189B9j/  
import java.net.*; # <&=ZLN  
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public class SiteFileFetch extends Thread { ~'T]B{.+J  
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SiteInfoBean siteInfoBean = null; //文件信息Bean K<|eZhp~  
long[] nStartPos; //开始位置 n|^-qy'w  
long[] nEndPos; //结束位置 A?6b)B/e?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 eUBk^C]\  
long nFileLength; //文件长度 6= 9  
boolean bFirst = true; //是否第一次取文件 JQbI^ef_;  
boolean bStop = false; //停止标志 +F67g00T|  
File tmpFile; //文件下载的临时信息 TWxMexiW  
DataOutputStream output; //输出到文件的输出流 gk]r:p<O  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） dd$\Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]`UJwq  
{ x{ZcF=4  
siteInfoBean = bean; N 4,w  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); u2U@Qrs2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); f Z\Ev%F  
if(tmpFile.exists ()) fT'A{&h|U  
{ uYO?Rb&}  
bFirst = false; N8mK^{  
read_nPos(); cJH7zumM)  
} (cA=~Bw[=  
else w@oq.K  
{ VDQ&BmJE  
nStartPos = new long[bean.getNSplitter()]; LU%g>?m.]  
nEndPos = new long[bean.getNSplitter()]; <vb
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} hr)TC-  
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} iOD9lR`s  
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public void run() JXvHsCd?  
{ iAXx`>}m  
//获得文件长度 DpTQPu9  
//分割文件 TmUn/  
//实例FileSplitterFetch -98bX]8  
//启动FileSplitterFetch线程 Y3-15:-  
//等待子线程返回 wV(_=LF  
try{ n}._Nb 5  
if(bFirst) 9Uk9TG5  
{ V#sANi?mpo  
nFileLength = getFileSize(); Q2k\8i  
if(nFileLength == -1) 7G
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{ ,sJ{2,]~  
System.err.println("File Length is not known!"); 5F0sfX  
} guf+AVPno  
else if(nFileLength == -2) @o>2:D1G  
{ 5a_K|(~3I  
System.err.println("File is not access!"); _39b8s{  
}
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else cvc.-7IO  
{ B|!YGfL  
for(int i=0;i<nStartPos.length;i++) 47t^{WrT  
{ |
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); [.6uw=;o  
} jPbL3"0A&  
for(int i=0;i<nEndPos.length-1;i++) U8.DPRa  
{ 5@Rf]'1B0  
nEndPos = nStartPos[i+1]; KL -8Aj~  
} wGbD%=  
nEndPos[nEndPos.length-1] = nFileLength; vO"AJ`_  
} ]bX.w/=  
} b},OCVT?  
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//启动子线程 s<^UAdLnl  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7] ~'8  
for(int i=0;i<nStartPos.length;i++) B%r)~?6DM  
{ LR`/pet  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aP4r6lLv+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N(F9vZOs  
nStartPos,nEndPos,i); VpJ
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !q$IB?8   
fileSplitterFetch.start(); ~IlgcCF  
} ;i,yT ?so  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,9q5jOnk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w`i3B@w  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |E!xt6B  
nEndPos = " + nFileLength); a:@Eg;aN*O  
// fileSplitterFetch[nPos.length-1].start(); 3pl.<;9r  
^8We}bs-c  
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//等待子线程结束 
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//int count = 0; t1Cyyb  
//是否结束while循环 m#8mU,7  
boolean breakWhile = false; b/2t@VlL  
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S* <:He&1  
while(!bStop) oBIKtS*L  
{ !&! sn"yD  
write_nPos(); (8{h I  
Utility.sleep(500); t'7)aJMP  
breakWhile = true; ="Dmfy7  
n {^D_S  
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for(int i=0;i<nStartPos.length;i++) o2Z# 5-  
{  E#ti  
if(!fileSplitterFetch.bDownOver) Y$%Ze]~  
{ 4xg%OH
 
breakWhile = false; _.\p^ HM  
break; NlWIb2,  
} \}G/F
!  
} D(L%fK`+  
if(breakWhile) %hOe `2#$  
break; 6kYn5:BhIi  
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`ZNzDr  
//count++; M-0BQs`N  
//if(count>4) v')T^b F@  
// siteStop(); ~ dmyS?Or  
} |?{Zx&yUw  
@u$4{sjgf\  
/|hKZTZJdN  
System.err.println("文件下载结束！"); _H@S(!  
} uvZ|6cM  
catch(Exception e){e.printStackTrace ();} 
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}
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//获得文件长度 {6v+ Dz>  
public long getFileSize() "4i(5|whp?  
{ S,qsCnz  
int nFileLength = -1; _[IN9ZC2G  
try{ 6?(*:}Q  
URL url = new URL(siteInfoBean.getSSiteURL()); }&EPH}V2n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8CwgV  
httpConnection.setRequestProperty("User-Agent","NetFox"); <C]s\"o-`  
:8\z 0  
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int responseCode=httpConnection.getResponseCode(); i!sKL%z}  
if(responseCode>=400) h<.&,6R  
{ M%yT?R+  
processErrorCode(responseCode); >L5[dkg%  
return -2; //-2 represent access is error 'TezUBRAz  
} B!rY\ ?W  
_fa2ntuS=f  
+>37'PD  
String sHeader; $Jx] FZDQ  
 :\gdQG  
;h3c+7u1  
for(int i=1;;i++) 6YYZ S2  
{ =d&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _ jF, k>F  
//Utility.log(in.readLine()); k q_B5L?  
sHeader=httpConnection.getHeaderFieldKey(i); ,Cde5A{K  
if(sHeader!=null) _q+H>1.&9  
{ ~B|K]&/]  
if(sHeader.equals("Content-Length")) -hyY5!rD  
{ :J}L| `U9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (4x`/  
break; sDw&U?gUv  
} /oE@F178  
} \_CC6J0k  
else O~l WFaW  
break; f*LDrAf9  
} qeHb0G  
} `A3"*,|z
 
catch(IOException e){e.printStackTrace ();} Kcl>uAgU  
catch(Exception e){e.printStackTrace ();} l]^uVOX  
k G4v>  
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Utility.log(nFileLength); m".8-
 
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return nFileLength; D3|y|Dr  
} wHAoO#`wn5  

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WEOW6UV(  
//保存下载信息（文件指针位置） 0,E*9y}  
private void write_nPos() LoqS45-)  
{ xW!2[.O5H  
try{ UuzT*Y>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ae;> @k/|=  
output.writeInt(nStartPos.length); mfg{% .1  
for(int i=0;i<nStartPos.length;i++) rAM{<  
{ N
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// output.writeLong(nPos); nV@k}IJg:?  
output.writeLong(fileSplitterFetch.nStartPos); @y2{LUJe  
output.writeLong(fileSplitterFetch.nEndPos); ][I}yOD70  
} dzKI?i)x  
output.close(); x9p,j  
} d[6[3B  
catch(IOException e){e.printStackTrace ();} w0q.cj@nd  
catch(Exception e){e.printStackTrace ();} _>S."cm}!k  
} pmv;M`_|R  
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//读取保存的下载信息（文件指针位置） 
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private void read_nPos() OB.TAoH:  
{ XFUlV;ek  
try{ T/X[q7O~~4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T;-&3  
int nCount = input.readInt(); i<m1^a#C'  
nStartPos = new long[nCount]; ZQlja  
nEndPos = new long[nCount]; rB}Iwp8  
for(int i=0;i<nStartPos.length;i++) Lf4c[[@%gd  
{ [z'PdYQR/{  
nStartPos = input.readLong(); jO&sS?  
nEndPos = input.readLong(); I'Ui` :A  
} 2g$PEwXe  
input.close(); >;-.rJFr
 
} 6F(;=iY8  
catch(IOException e){e.printStackTrace ();} ?suxoP%  
catch(Exception e){e.printStackTrace ();} /5b,&  
} 5 <X.1T1  
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private void processErrorCode(int nErrorCode) Po~{Mpe  
{ ,9SBGxK5`  
System.err.println("Error Code : " + nErrorCode); 2_'{f1bVxz  
} ^_0zO$z,  
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r#M0X^4A  
//停止文件下载 Y@)/iwq  
public void siteStop() AqM}@2#%%  
{ }1kT0*'L  
bStop = true; omisfu_~E  
for(int i=0;i<nStartPos.length;i++) w~{NNK;"j  
fileSplitterFetch.splitterStop(); h mC.5mY  
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} H
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} "#Qqwsw7  
//负责部分文件的抓取 dT?/9JIv  
**FileSplitterFetch.java efW<  
*/ O10,h(O  
package NetFox; c5Fl:=h  
>NwS0j$j@  
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import java.io.*; lgWEB3f .  
import java.net.*; DyhW_PH2J  
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public class FileSplitterFetch extends Thread { OMgFp|^  
<Ih)h$8`  
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String sURL; //File URL )(V|d$n  
long nStartPos; //File Snippet Start Position .dM4B'OA?  
long nEndPos; //File Snippet End Position rWsUWA T*  
int nThreadID; //Thread's ID %xv }  
boolean bDownOver = false; //Downing is over j N":9+F  
boolean bStop = false; //Stop identical &m<:&h& b  
FileAccessI fileAccessI = null; //File Access interface 90<z*j$EK  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "V|&s/9  
{ StZ GKY[Q  
this.sURL = sURL; mu`:@7+Yp  
this.nStartPos = nStart; P`^3-X/  
this.nEndPos = nEnd; T)4pLN E  
nThreadID = id; CNP!v\D  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [[ {L#  
} t,H=;U#  
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public void run() mcO/V-\5'  
{ drRi<7 i  
while(nStartPos < nEndPos && !bStop) K X0{dizZ  
{
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try{ "L ,)4v/J  
URL url = new URL(sURL); % \N52  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8);G'7O  
httpConnection.setRequestProperty("User-Agent","NetFox"); l5
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String sProperty = "bytes="+nStartPos+"-"; TQhu$z<  
httpConnection.setRequestProperty("RANGE",sProperty); P)D2PVD  
Utility.log(sProperty); jgpSFb<9F  
5 1&||.  
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InputStream input = httpConnection.getInputStream(); Z@sDxYt9  
//logResponseHead(httpConnection); X"hdCY%  
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byte[] b = new byte[1024]; q)N]*~  
int nRead; oyfY>^bs  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #
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{ 5ub|r0&M  
nStartPos += fileAccessI.write(b,0,nRead);
kxvzAKz~  
//if(nThreadID == 1) GQ-fEIi{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]]"O)tWHj  
} WZh%iuI{C  
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>G#SfE$0  
Utility.log("Thread " + nThreadID + " is over!"); WlJ=X$  
bDownOver = true; r~2>_LK  
//nPos = fileAccessI.write (b,0,nRead); 'aV/\a:*  
} NQ&\t[R[  
catch(Exception e){e.printStackTrace ();} r.z=  
} ~(v7:?  
} c2E*A+V#u  
SLsw '<  
9I1D'7wI^^  
//打印回应的头信息 Q{K'#  
public void logResponseHead(HttpURLConnection con) O%m\ Q1  
{ =(aA`:Nl  
for(int i=1;;i++) qz_'v{uAj  
{ _dQg5CmlG  
String header=con.getHeaderFieldKey(i); uPhL?s{  
if(header!=null) G>@KX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;URvZ! {/Z  
Utility.log(header+" : "+con.getHeaderField(header)); #S4lRVt5  
else sV']p#HK0  
break; (8Ptuh6\\2  
} \-`,fat  
} mG\$W#+j  
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-|.Izgc  
public void splitterStop() n5qg6(Tl]  
{ XK+" x!   
bStop = true; Vd&&GI(:?^  
} ojva~mnFf  
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3u,CI!  
} _Jt  
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/* :MPfCiAv  
**FileAccess.java /}kG$~  
*//文件访问(定位，写) qdCcMcGt  
package NetFox; y3+iADo.p  
import java.io.*; L^E#"f  
QKB*N)%6  
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public class FileAccessI implements Serializable{ 93[&'  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3xX^pjk  
RandomAccessFile oSavedFile; :5W8S6[o  
long nPos;
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h<0&|s*a)  
public FileAccessI() throws IOException 4roqD;5|~|  
{ eJ ;a}{ 4%  
this("",0); b0|;v-v  
} ASU.VY  
ou\M}C`E  
b/soU2?^  
public FileAccessI(String sName,long nPos) throws IOException Abc%V
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{ *}h#'+  
oSavedFile = new RandomAccessFile(sName,"rw"); Q94Lq~?YF  
this.nPos = nPos; 2 ":W^P  
oSavedFile.seek(nPos); 3 BQZ[%0@  
} b2r]>*Vc  
|L<p90  
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public synchronized int write(byte[] b,int nStart,int nLen) tv 7"4$T  
{ 4`[2Te>  
int n = -1; 2{}8_G   
try{ 5._1G| 3  
oSavedFile.write(b,nStart,nLen); <zWMTVaC  
n = nLen; W/@-i|v  
} Kt5k_9
 
catch(IOException e) , G2(l  
{ dTrz7ay
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e.printStackTrace (); [,0[\NC  
}  DJJd_  
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return n; p>=i'~lQ6  
} v$)ZoM6E  
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} w!|jL $5L  
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b  
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/* ,CxIA^  
**SiteInfoBean.java 90Bn}@t=Q  
*/ IgyoBfj\d  
package NetFox; 5q,ZH6\ {  
s1>d)2lX  
"&%Lhyt  
public class SiteInfoBean { 7U1^=Y@t}  
-T=sY/O  
{2.zzev'  
private String sSiteURL; //Site's URL &V(;zy4(R  
private String sFilePath; //Saved File's Path #ZyY(S1.  
private String sFileName; //Saved File's Name Zg&o][T  
private int nSplitter; //Count of Splited Downloading File 6Z#$(oC  
G0Y]-*1  
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public SiteInfoBean() J3QL%#  
{//nSplitter的缺省值为5 i4}+n^oSYo  
//default value of nSplitter is 5 2|A?9aE%0  
this("","","",5); k?;@5r)y-  
} gwyX%9  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) lx{ ' bzv  
{ 3|Y2BAd  
sSiteURL= sURL; 0dW*].Gi:  
sFilePath = sPath; -, uT8'  
sFileName = sName; 1c|{<dFm  
this.nSplitter = nSpiltter; hS'!JAM>Q  
pEp$J;   
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} [NoOA  
(Xl+Zi>\{  
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public String getSSiteURL() b5)a6qtb  
{ 5p]V/<r  
return sSiteURL; RxE.t[  
} B9dc*  
\GPTGi5A  
l T#WM]  
public void setSSiteURL(String value) )kEH}P&  
{ {X
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sSiteURL = value; ntQW+!s
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} /:@)De(S  
6~OJB!  
&LYH >  
public String getSFilePath() ~e_  
{ z?n6l7sH  
return sFilePath; pIHpjx  
} ` >loleI  
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public void setSFilePath(String value) ~gdnD4[G  
{ ?sv[vR(  
sFilePath = value; .hRtQU  
} Dkg^B@5Xr  
M%Zh{  
A|(!\J0  
public String getSFileName() 39~te%;C7  
{ BtrMv6  
return sFileName; RiZ)#0  
} 22/"
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public void setSFileName(String value) K'f^=bcI  
{ I;9C":'#  
sFileName = value; sIMN""@Y^  
} P@5}}vwS  
lnGg1/
  
D*/fY=gK  
public int getNSplitter() g:s|D hE[  
{ E/<n"'0ek  
return nSplitter; O^n\lik  
} OX7a72z  
WmOu#5*;  
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public void setNSplitter(int nCount) J"-/ok(<@  
{ R*?!xDJ  
nSplitter = nCount; ^Y%<$I
FG  
} ~ike&k{  
} 9iV9q]($0  
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/* mU]pK5  
**Utility.java RivhEc1h%  
*/ ?{P$|:ha  
package NetFox; 'Ck:=V%}g  
{v"Y!/ [z  
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public class Utility { }USOWsLSt  
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public Utility() W$<Y**y9m  
{ /9,y+"0SQz  
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} ++eT 0  
u2IU/z8 ^  
//线程睡眠 {Iz"]Wh<f  
public static void sleep(int nSecond) 4+89 M  
{ SkmKf~v  
try{ *zMt/d*<&  
Thread.sleep(nSecond); Jpc%i8  
} /A+5q\8G  
catch(Exception e) /Ny#+$cfk  
{ 7uf5w0]
  
e.printStackTrace (); 9fWR8iV  
} h8 FV2"  
} >2F9Tz,3  
=?_:h`}  
//日志 :2V|(:^'  
public static void log(String sMsg) 1,7 }ah_  
{ <rvM)EJv|  
System.err.println(sMsg); hkRqtpYK  
} OdOn wY  
/([a%,DI  
^M\X/uq$E  
public static void log(int sMsg) \}\# fg  
{ O`I}Lg]~q  
System.err.println(sMsg); *\B(-  
} 6ma.FvSIM  
} A]1dR\p  
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O0s,)8+z5D  
/* W*?qOq {  
**TestMethod.java 3dJiu  
*/ )3O#T$h  
package NetFox; 1]Cdfj6@  
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Mf !S'\  
public class TestMethod {
f@q.kD21  
v2a(yH  
+_25E.>ml  
public TestMethod() KdD~;Ap$  
{ ///xx/weblogic60b2_win.exe {c~w Ms#  
try{ _~'M
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [e_<UF@A*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &M tF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [mj=m
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fileFetch.start(); cB_9@0r[S  
} J@QOF+&  
catch(Exception e){e.printStackTrace ();} DliDBArxZ  
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} eCWF0a  
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public static void main(String[] args) RCi8{~rIvS  
{ 4"\x#  
new TestMethod(); @BPQ >  
} O S#RCN*  
}  w%::
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