http断点续传简单实现（java)

/* 4^[}]'w  
**SiteFileFetch.java +'['HQ)  
*/ 3$N %iE
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package NetFox; *e3L4 7"G  
import java.io.*; }u-S j/K  
import java.net.*; .pIR/2U\F  
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public class SiteFileFetch extends Thread { HKiVEg  
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SiteInfoBean siteInfoBean = null; //文件信息Bean z/0yO@_D/q  
long[] nStartPos; //开始位置 <F)w=_%&  
long[] nEndPos; //结束位置 &#-|Yh/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <,@H;|mZ  
long nFileLength; //文件长度 <DXmZ1  
boolean bFirst = true; //是否第一次取文件 KIKq9*  
boolean bStop = false; //停止标志 4aN+}TkH@G  
File tmpFile; //文件下载的临时信息 0n*rs=\VG  
DataOutputStream output; //输出到文件的输出流 Wg`+u  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ~TG39*m  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?..i4  
{ eA1k)gjE  
siteInfoBean = bean; (L y%{ Y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jy!f{dsC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); f^!11/Wv  
if(tmpFile.exists ()) q8?
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{ XhE$&Ff  
bFirst = false; Mr=}B6`  
read_nPos(); #.)xm(Ys  
} $-$5ta{s  
else L2CW'Hd  
{ &@4.;u  
nStartPos = new long[bean.getNSplitter()]; V;iL[  
nEndPos = new long[bean.getNSplitter()]; dd\bI_  
} D|TLTF"  
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}
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public void run() 1Q&cVxA"\  
{ 0NQ7#A  
//获得文件长度 e=gboR  
//分割文件 oMh~5 W  
//实例FileSplitterFetch |h^K M  
//启动FileSplitterFetch线程 n> MD\ZS  
//等待子线程返回 t/JOERw  
try{ n 5~=qQK2  
if(bFirst) |`w$|pm=  
{ <ZigCo w  
nFileLength = getFileSize(); AA))KBXq  
if(nFileLength == -1) a?zR
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{ j6n2dMRvSE  
System.err.println("File Length is not known!"); $42Au2Jg  
} _qY`KP"  
else if(nFileLength == -2) 968Ac}OA  
{ i^je.,Bi  
System.err.println("File is not access!"); [urH a  
} =LXvlt'Q34  
else cJP'ShnCh  
{ C0\%QXu  
for(int i=0;i<nStartPos.length;i++) YO)')&  
{ xJvLuzUD  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5Xwk*@t2a  
} r~)VGdB+  
for(int i=0;i<nEndPos.length-1;i++) .r~'(g{qt  
{ shM{Y9~O9&  
nEndPos = nStartPos[i+1]; UUl*f!&
o  
} wX-RQ[2X  
nEndPos[nEndPos.length-1] = nFileLength; NmjzDN  
} azvDvEWCQZ  
} yrO?Np  
+``>,O6  
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//启动子线程 XK1fHfCEa  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; PPN q:,  
for(int i=0;i<nStartPos.length;i++)
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{ Ip>^O/}$1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NeY"6!;k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :OHSxb>[  
nStartPos,nEndPos,i); >[K0=nA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <E"*)Oi  
fileSplitterFetch.start(); '#H&:Htm;L  
} `Gf{z%/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), * !X4&#xP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z%Vr+)!4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", fb/qoZ  
nEndPos = " + nFileLength); l#Yx
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// fileSplitterFetch[nPos.length-1].start(); gyC^K3}  
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//等待子线程结束 Wt(Kd5k0'2  
//int count = 0; . /Y&\<  
//是否结束while循环 P2>:p%Z
  
boolean breakWhile = false; w.tW=z5  
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while(!bStop) B-$+UE>%  
{ _ ~|Q4AJ  
write_nPos(); ?k"0w)8  
Utility.sleep(500); Axf^
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breakWhile = true; U>oW~Z  
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for(int i=0;i<nStartPos.length;i++) t7&Dwmck9  
{ RXM}hqeG  
if(!fileSplitterFetch.bDownOver) "tKNlHBu'  
{ bhn5Lz$z  
breakWhile = false; b]w[*<f?  
break; /V#7=,,  
} 5.dl>,  
} <z',]hy  
if(breakWhile) @/LiR>,  
break; `&H04x"Y$>  
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//count++; V;k#})_-  
//if(count>4) .wD>Gs{sH[  
// siteStop(); ^Wm*-4  
} ?&6Q%IUW1  
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System.err.println("文件下载结束！"); BR3wX4i\  
} 5*Btb#:  
catch(Exception e){e.printStackTrace ();} -8/JP  
} FJ}gUs{m  
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//获得文件长度 IhfZLE.,  
public long getFileSize() TVYz3~m  
{ QAi1,+y]7w  
int nFileLength = -1; $C$ub&D ~"  
try{ R1Yqz $#  
URL url = new URL(siteInfoBean.getSSiteURL()); )%t7\1)B3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fq=:h\\G  
httpConnection.setRequestProperty("User-Agent","NetFox"); {l@WCR  
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int responseCode=httpConnection.getResponseCode(); m2Q$+p@  
if(responseCode>=400) WU7cF81$  
{ Bh,Q8%\6  
processErrorCode(responseCode); n7S; Xve#  
return -2; //-2 represent access is error @<a|  
} bM^7g  
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String sHeader; 7VY8CcL  
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for(int i=1;;i++) Wt:~
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{ &//2eL  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }2=hd..  
//Utility.log(in.readLine()); c})wD+1  
sHeader=httpConnection.getHeaderFieldKey(i); :]-$dEu&  
if(sHeader!=null) \FXp*FbQ  
{ {:$NfW  
if(sHeader.equals("Content-Length")) MO TE/JG  
{ CbQ4
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _ ~[M+IO   
break; ^N{k6
>;  
} gvlFumg
2  
} 7 OWsHlU  
else x9D/s`!  
break; _@K YF)  
} ?<6@^X"  
} 7O$ &  
catch(IOException e){e.printStackTrace ();} @h9K  
catch(Exception e){e.printStackTrace ();} K[]K53Nk  
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Utility.log(nFileLength); -K^41W71  
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return nFileLength; mrqaM2,(I  
} B!uxs  
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//保存下载信息（文件指针位置） ]
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private void write_nPos() OpUA{P  
{ . pP7"E4]  
try{ A2BRbwr>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gyFr"9';c  
output.writeInt(nStartPos.length); 0 u2Ny&6w  
for(int i=0;i<nStartPos.length;i++) #9,=Owup  
{ D2]ZMDL.  
// output.writeLong(nPos); K~3Ebr  
output.writeLong(fileSplitterFetch.nStartPos); &F`L}#oL&  
output.writeLong(fileSplitterFetch.nEndPos); ^RDU p5,T  
} GW8CaTf~  
output.close(); cm,4&x6  
} uY]T:UVk
 
catch(IOException e){e.printStackTrace ();} QTE:K?  
catch(Exception e){e.printStackTrace ();} IM]h*YV'  
} dN0mYlu1|  
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/=/ HB  
//读取保存的下载信息（文件指针位置） HzEGq,.  
private void read_nPos() 3.FR C  
{ ONfyYM?  
try{ LuL$v+`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~j]d
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int nCount = input.readInt(); 10O3Z9  
nStartPos = new long[nCount]; O4!9{  
nEndPos = new long[nCount]; 0Az/fzJlz  
for(int i=0;i<nStartPos.length;i++) mw
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{ b!,j
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nStartPos = input.readLong(); f~R[&q+  
nEndPos = input.readLong(); ofK='G.  
} M}KZG'7  
input.close(); j/' g$  
} =hhvmo  
catch(IOException e){e.printStackTrace ();} H0+:XF\M  
catch(Exception e){e.printStackTrace ();} RJwb@r<v  
} q<EEb  
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private void processErrorCode(int nErrorCode) 8,y{q9O  
{ vnZ4(  
System.err.println("Error Code : " + nErrorCode); s-%J5_d f  
} +N8aq<l  
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//停止文件下载 J?,?fqb  
public void siteStop() -f 4>MG  
{ ^}hZ'<PK  
bStop = true; Bz:&f46{  
for(int i=0;i<nStartPos.length;i++) 3>M.]w6{  
fileSplitterFetch.splitterStop(); q}sK  
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} XECikld>  
} #'8)u)!  
//负责部分文件的抓取 )vQNiik#  
**FileSplitterFetch.java PLdf_/]-  
*/ G:DSWW}  
package NetFox; o
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import java.io.*;
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import java.net.*; CC>($k"  
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public class FileSplitterFetch extends Thread { cCk1'D|X[e  
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String sURL; //File URL z1FL8=  
long nStartPos; //File Snippet Start Position f}%sO  
long nEndPos; //File Snippet End Position ?;fv!'?%  
int nThreadID; //Thread's ID pJn>oGeJ&  
boolean bDownOver = false; //Downing is over $82zyq  
boolean bStop = false; //Stop identical Yx!n*+:J  
FileAccessI fileAccessI = null; //File Access interface "raj>2@  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 418gcg6)  
{ Rd0?zEKV  
this.sURL = sURL; }FZp840  
this.nStartPos = nStart; 6kC)\uy  
this.nEndPos = nEnd; =^by0E2  
nThreadID = id; bje'Oolc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 j~.u>4  
} 0O_E\
- =  
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9 #:ue@)  
public void run() dbd"pR8v  
{ oR77`  
while(nStartPos < nEndPos && !bStop) |NXFla  
{ h%u?lW  
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try{ =qan%=0"h  
URL url = new URL(sURL); ,I=O"z>9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N!Rt;Xm2@  
httpConnection.setRequestProperty("User-Agent","NetFox"); D8W(CE^}  
String sProperty = "bytes="+nStartPos+"-"; }WoX9M; 1  
httpConnection.setRequestProperty("RANGE",sProperty); =g1D;  
Utility.log(sProperty); N0=b[%g;n  
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InputStream input = httpConnection.getInputStream(); Xp.|.)Od  
//logResponseHead(httpConnection); Gtf1}UJC  
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byte[] b = new byte[1024]; (Jm(}X]sh[  
int nRead;
)_WH#-}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~rp.jd 0l  
{ *'s&/vEy  
nStartPos += fileAccessI.write(b,0,nRead); iFY]0@yt  
//if(nThreadID == 1) P"U>tsHK:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4{c`g$j>  
} E\W;:p,{A  
&0?DL  
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Utility.log("Thread " + nThreadID + " is over!");  j@s=ER  
bDownOver = true; rAtai}Lx  
//nPos = fileAccessI.write (b,0,nRead); *vEU}SxRuv  
} jp"XS  
catch(Exception e){e.printStackTrace ();} 9*"[pt+tA  
} 6f<*1YR F  
} g4
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//打印回应的头信息 Ov F8&*A  
public void logResponseHead(HttpURLConnection con) 9_I[o.q   
{ O(b"F? w  
for(int i=1;;i++) q=(M!9cE  
{ "'Q$.sR  
String header=con.getHeaderFieldKey(i); bf&.rJ0  
if(header!=null) 6yV5Yjs  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |s)VjS4@  
Utility.log(header+" : "+con.getHeaderField(header)); fq)Ohb  
else 3uB=L7.  
break; Ih9O
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} ]0at2  
} &6=TtTp"9  

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public void splitterStop() p7?CeyZ-V  
{ E` :ZH  
bStop = true; 3Y.d&Nz  
} I_R5\l}O+D  
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} rF <iWM=  
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/* ][T9IAn  
**FileAccess.java 2`q^Q  
*//文件访问(定位，写) +?J_6Mo@X  
package NetFox; M9ter&  
import java.io.*; Y,<WX v  
k}+MvGq  
M4L~bK  
public class FileAccessI implements Serializable{ .~V".tZV[  
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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 @eAGN|C5  
RandomAccessFile oSavedFile; Ynk><0g6  
long nPos; jSOa   
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public FileAccessI() throws IOException vh:UXE lm  
{ A1=$kzw{UH  
this("",0); .lNnY8<  
} [|m>vY!  
 \!' {-J  
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public FileAccessI(String sName,long nPos) throws IOException gn4g 43  
{ hCOy\[2$  
oSavedFile = new RandomAccessFile(sName,"rw"); .aAw7LW  
this.nPos = nPos; z?IY3]v*z<  
oSavedFile.seek(nPos); i85+p2i7  
} |n-a\  
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public synchronized int write(byte[] b,int nStart,int nLen) 3qV>TE]6,  
{ ?L~=Z\H  
int n = -1; x"h)"Y[c5  
try{ h\: tUEg#J  
oSavedFile.write(b,nStart,nLen); =":V WHf  
n = nLen; k*UR#z(I  
} jT wM<?  
catch(IOException e) v=yI#
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{ gen3"\Og{  
e.printStackTrace (); n<"a+TTU  
} 5D02%U2N)G  
>> 8KL`l  
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return n; KzFs#rhpn  
} MlcoOi!  
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} hnfrnYH  
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ED
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/* R~seUW7uv"  
**SiteInfoBean.java "l2N_xX;  
*/ yI)RGOV  
package NetFox; KI?1(L  
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public class SiteInfoBean { ;r@R (Squ  
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de  
vGLb2Q  
private String sSiteURL; //Site's URL yKk,);  
private String sFilePath; //Saved File's Path Ul~}@^m]4}  
private String sFileName; //Saved File's Name W2o8Fu   
private int nSplitter; //Count of Splited Downloading File fN? Lz%z3  
+ 1%^c(3  
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public SiteInfoBean() #lVl?F+~  
{//nSplitter的缺省值为5 [ QL<&:s&  
//default value of nSplitter is 5 gu%'M:Xe  
this("","","",5); 8@C|exAD`  
} 2W-NCE%K)T  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) EA{*%9 A  
{ z(#hL-{c  
sSiteURL= sURL; $4~}_phi  
sFilePath = sPath; OQb9ijLeK  
sFileName = sName; Chi<)P$^  
this.nSplitter = nSpiltter; {,mRMDEy  
/v ;Kb|e  
^Th"`Av5  
} 9p'J(`  
>yHnz?bf@  
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public String getSSiteURL() (w:ACJ[[  
{ *gpD4c7A\  
return sSiteURL; Xq)%w#l5?  
}  eJ\j{-  
xwp?2,<  
o)D+qiA3U  
public void setSSiteURL(String value) U\GZ  
{ G(3la3\(  
sSiteURL = value; rxk{Li<9  
} eu|q {p  
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public String getSFilePath() ffd3QQ  
{ nL20}"$E  
return sFilePath; AFUl  
} 5VoiDM=\c  
&/FwV'  
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public void setSFilePath(String value) 'yjH~F.  
{ trt\PP:H%  
sFilePath = value; F@K;A%us)  
} t? Ja q  
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l#.,wOO{  
public String getSFileName() ]7 mSM  
{ ?^5*[H  
return sFileName; ?Gw89r  
} Y. tFqzo3  
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9?,.zc
^  
public void setSFileName(String value) lc#zS_  
{ -s "$I:v  
sFileName = value; C>VZf,JE1  
} 4x=Y9w0?8  
fG5}'8  
' uw&f;/E  
public int getNSplitter() TBT*j&!L  
{ #vwXx
r  
return nSplitter; =)5a=^ 6  
} 6u;(R0n  
=@  
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public void setNSplitter(int nCount) 8QBL:7<  
{ Z"T(8>c;g  
nSplitter = nCount; N)Kr4GC  
} uelTsn  
} =upP3rw  
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/* U8z"{  
**Utility.java +[`%b3Nk  
*/ 0E1
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package NetFox; ?\r3 _  
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public class Utility { 6s2g+[  
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public Utility() X\RTHlw']  
{ *^_!W'T{j  
_,~zy9{,  
e84TLU?~  
} *?&O8SSBH  
o-=lHtR  
//线程睡眠 Hm*#HT%#  
public static void sleep(int nSecond) .x%SbG<k{  
{ oFp&j@`k8j  
try{ itvdzPO  
Thread.sleep(nSecond); %L.+r!
.  
} bnQO}G  
catch(Exception e) &r%3)Z8Et  
{ UkV] F
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e.printStackTrace (); (5_(s`q.  
} )_?$B6hf,&  
} .`].\Zykf  
:g";p.~=  
//日志 &pz8vWCk  
public static void log(String sMsg) ZeZwzH)BD  
{ 8{u01\0}  
System.err.println(sMsg); &@-glF5  
} 'h6RZKG T  
%-CC_R|0$  
}Jfo(j  
public static void log(int sMsg) )`^:G3w  
{ 9n7d "XD2  
System.err.println(sMsg); a=dN.OB}F7  
} wQc w#  
} r~!lD9R~  
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/* %Z4=3?5B"9  
**TestMethod.java < r~Tj  
*/ <~OyV5:6  
package NetFox; y]_DW6W  
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|z%,W/Ef  
public class TestMethod { n21J7;\/+  
rpmDr7G  
s-B\8&^C  
public TestMethod() Xk$lQMwZ  
{ ///xx/weblogic60b2_win.exe =F4}  
try{ Cn<x  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Tx(R3B+u7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); '\Ub*m((1O  
SiteFileFetch fileFetch = new SiteFileFetch(bean); S SXSgp  
fileFetch.start(); ks}o9[D3  
} O
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catch(Exception e){e.printStackTrace ();} W#!\.m`5  
:-)[B^0  
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} ]O."M"B  
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public static void main(String[] args) rxARJso  
{ xcig'4L  
new TestMethod(); gi)/iz`  
} QVpZA,  
} y^Lw7  
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