http断点续传简单实现（java)

/* 1 Szv4  
**SiteFileFetch.java SYA0Hiw7P  
*/ COH9E
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package NetFox; o?/fObV@(  
import java.io.*; zbAyYMtEk  
import java.net.*; Mz: "p.  
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public class SiteFileFetch extends Thread { )-^[;:B\k"  
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 ?)2;W  
SiteInfoBean siteInfoBean = null; //文件信息Bean pcNpr`  
long[] nStartPos; //开始位置 z-JYzxL9  
long[] nEndPos; //结束位置 NeR1}W  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 N) '|l0x0  
long nFileLength; //文件长度 b8&z~'ieR  
boolean bFirst = true; //是否第一次取文件 ?/}-&A"  
boolean bStop = false; //停止标志 _rz7)%Y'#$  
File tmpFile; //文件下载的临时信息 @*=eqO  
DataOutputStream output; //输出到文件的输出流 (05a9  
mbXW$E-&R2  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [z,6K=  
public SiteFileFetch(SiteInfoBean bean) throws IOException .TO#\!KBv  
{ K'oy6$B  
siteInfoBean = bean; nG~^-
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^_t7{z%sA[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jIjW +D`  
if(tmpFile.exists ()) K>_~|ZN1C8  
{ q.ZkQN+  
bFirst = false; G2w0r,[  
read_nPos(); 6+/BYN!&4  
} 4VP$,|a  
else .5!Q(  
{ 
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nStartPos = new long[bean.getNSplitter()];
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nEndPos = new long[bean.getNSplitter()]; ]SUW"5L-  
} tZygTvK/S  
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} o'=i$Eb  
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public void run() T/P   
{ KJW^pAj$B  
//获得文件长度 jdd3[  
//分割文件 $|VD+[jSV  
//实例FileSplitterFetch '5\?l:z  
//启动FileSplitterFetch线程 eA-$TSWh  
//等待子线程返回 ^C~t)U  
try{ ;aDYw [  
if(bFirst) ?i$MinK  
{ @=qWwt4~  
nFileLength = getFileSize(); K~A@>~vFb  
if(nFileLength == -1) +r$VrNVs  
{ /
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System.err.println("File Length is not known!"); 22R ,  
} >'v{o{k|C  
else if(nFileLength == -2) "@L|Z6U(  
{ p~z\&&0U0  
System.err.println("File is not access!"); GRAPv|u9[  
} -# /'^O+%  
else :oytJhxU  
{ =xr2-K)e  
for(int i=0;i<nStartPos.length;i++) )JOo|pr-K  
{ C,$7fW{?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); xG|lmYt76  
} wp<f{^ et  
for(int i=0;i<nEndPos.length-1;i++) 0}-
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{ b$Q#Fv&P  
nEndPos = nStartPos[i+1]; __i))2  
} smPZ%P}P+c  
nEndPos[nEndPos.length-1] = nFileLength; h%&2M58:  
} oiItQ4{<  
} K Vnz{cx`  
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//启动子线程 (S8hr,%n  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; mV|Z5=f  
for(int i=0;i<nStartPos.length;i++) ,EH^3ODD  
{ /U=?D(>x  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6JD~G\$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7@Xi
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nStartPos,nEndPos,i); gFnJDR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "LM[WcDX  
fileSplitterFetch.start(); ,yTT,)@<  
} v(l:N@L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Tz{-L%*#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J )UCy;Y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Bs\&'=l  
nEndPos = " + nFileLength); vY]7oX+  
// fileSplitterFetch[nPos.length-1].start(); \iAs  
C,,S<=L:  
B1va]=([)W  
//等待子线程结束 7*@BCu6  
//int count = 0; i.''\  
//是否结束while循环 +m1*ou'K  
boolean breakWhile = false; `Gh#2U  
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while(!bStop)  \1?:  
{ ?{r-z3@ N  
write_nPos(); Q
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Utility.sleep(500); ),Igu  
breakWhile = true; q}hHoSG]=  
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for(int i=0;i<nStartPos.length;i++) QoS]QY'bZ  
{ ,j%f
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if(!fileSplitterFetch.bDownOver) Z(BZGO<  
{ aA-
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breakWhile = false; AX6l=jFZx  
break; BCt>P?,UO  
} -fDW>]_  
} RH"EO4  
if(breakWhile) /;`-[  
break; -qpe;=g&f  
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U)D}J_Zi(  
//count++; j~O"=?7!O  
//if(count>4) 0(+dXzcwM  
// siteStop(); v
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} Oox,4
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System.err.println("文件下载结束！"); Z>hGqFZ0{  
} 7%i6zP/a  
catch(Exception e){e.printStackTrace ();} 8)="Ee  
} Cf3<;Mp<  
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//获得文件长度 c@{M),C~E  
public long getFileSize() IaGF{O3.  
{ \+)AQ!E  
int nFileLength = -1; x%55:8{  
try{ qK
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URL url = new URL(siteInfoBean.getSSiteURL()); S=3H.D!f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ._(5; PB"  
httpConnection.setRequestProperty("User-Agent","NetFox"); "*N]Y^6/A  
_Q}vPSJviC  
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int responseCode=httpConnection.getResponseCode(); _q`f5*Z[  
if(responseCode>=400) k];fQ7}m<0  
{ Yw,LEXLY  
processErrorCode(responseCode); zI'c'X1,  
return -2; //-2 represent access is error D"X`qF6U7  
} [[KIuW~ot  
|L~RC  
=8EGB\P  
String sHeader; .p-T >  
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for(int i=1;;i++) td|O#R  
{ XO}v8nWV  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w s7LDY&(  
//Utility.log(in.readLine()); w>&g'  
sHeader=httpConnection.getHeaderFieldKey(i); d*Kg_He-  
if(sHeader!=null) =p&uQ6.i+  
{ 0-8'.C1v  
if(sHeader.equals("Content-Length")) xcQ:&q  
{ n(jrK9]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |4F'Zu}g>  
break; ,zh4oX`>  
} "PC9[i  
} k9iB-=X?4s  
else 2UEjn>2  
break; VP:9&?>G  
} mxl"Y&l2<  
} n4 J*04K  
catch(IOException e){e.printStackTrace ();} G/&Wc2k  
catch(Exception e){e.printStackTrace ();} (BY5omlh  
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Utility.log(nFileLength); N|asr,  
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return nFileLength; DTCOhUIV  
} m]/sR3yF  
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//保存下载信息（文件指针位置） {Zf 9} !qF  
private void write_nPos() _y
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{ ?9;r|G  
try{ g UA_&_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); [u7i)fn5?  
output.writeInt(nStartPos.length); AI2@VvB  
for(int i=0;i<nStartPos.length;i++) VHx:3G  
{ 6G<gA>V  
// output.writeLong(nPos); "M=1Eb$6=  
output.writeLong(fileSplitterFetch.nStartPos); n<Z1i)  
output.writeLong(fileSplitterFetch.nEndPos); {'[S.r`  
} fk(h*L|sI  
output.close(); YFs!,fw'  
} {S5j;  
catch(IOException e){e.printStackTrace ();} ,\D*=5  
catch(Exception e){e.printStackTrace ();} IeGVLC
  
} 2g%p9-MO]I  
$ 1v'CT  
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//读取保存的下载信息（文件指针位置） NSQ#\:3:S  
private void read_nPos() tQcn%CK  
{ "[\),7&03  
try{ I=K|1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U].3vju`c  
int nCount = input.readInt(); oPR?Ar  
nStartPos = new long[nCount]; "j?\Ze*  
nEndPos = new long[nCount]; 'S
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for(int i=0;i<nStartPos.length;i++) JI|MR#_u  
{ td(4Fw||1y  
nStartPos = input.readLong(); RV_+-m{]  
nEndPos = input.readLong(); i" >kF@]c8  
} =J^FV_1rJ  
input.close(); v42Z&PO
 
} L'<.#(|  
catch(IOException e){e.printStackTrace ();} GaLQ/V2R  
catch(Exception e){e.printStackTrace ();} I'%ASZ  
} S/xCX!  
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private void processErrorCode(int nErrorCode) )H-y  
{ ?T
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System.err.println("Error Code : " + nErrorCode); aX|LEZ;D>  
} @Jr@ fF}  
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//停止文件下载 z-
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public void siteStop() c_FnJ_++f  
{ -)p| i~j^A  
bStop = true; ]rc=oP;  
for(int i=0;i<nStartPos.length;i++) -*~~00w  
fileSplitterFetch.splitterStop(); GbJVw\5Z*  
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} S~Yu;  
} 70yM]C^  
//负责部分文件的抓取 |RZI]H%  
**FileSplitterFetch.java ;@V1*7y  
*/ d^^EfWU  
package NetFox; Z'o'd_g>I+  
&KVXU0F^z  
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import java.io.*;
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import java.net.*; W4n(6esO  
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public class FileSplitterFetch extends Thread { +/DT#}JE  
< <]uniZ\  
+l(lpp>,  
String sURL; //File URL )A:|8m  
long nStartPos; //File Snippet Start Position *e *V%w~75  
long nEndPos; //File Snippet End Position _q3|Ddm2LN  
int nThreadID; //Thread's ID n ?+dX^j  
boolean bDownOver = false; //Downing is over f%Vdao[  
boolean bStop = false; //Stop identical ;B6m;[M+  
FileAccessI fileAccessI = null; //File Access interface V25u_R`{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException S)vNWBO  
{ =SLCG.  
this.sURL = sURL; .yb=I6D;<3  
this.nStartPos = nStart; Kld#C51X f  
this.nEndPos = nEnd; S F&EVRv  
nThreadID = id; H:_R[u4r  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 c,_??8  
} GNab\M.  
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public void run() -1c{Jo  
{
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while(nStartPos < nEndPos && !bStop) sH /08Z  
{ =w2_1F"  
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try{ CCU<t Q  
URL url = new URL(sURL); m$}Jw<.W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (I\qTfN4  
httpConnection.setRequestProperty("User-Agent","NetFox"); GLr7sack  
String sProperty = "bytes="+nStartPos+"-"; (V9 ;  
httpConnection.setRequestProperty("RANGE",sProperty); b?nORWjC  
Utility.log(sProperty); D=:O^<  
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InputStream input = httpConnection.getInputStream(); vmIt!x  
//logResponseHead(httpConnection); Rxk0^d:sNi  
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byte[] b = new byte[1024]; ^@OdY&5^  
int nRead; J ` KyS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^Rc*X'Iz(!  
{ %)p?&_  
nStartPos += fileAccessI.write(b,0,nRead); SCo;Ek  
//if(nThreadID == 1) )Rr0f 8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }-H)jN^  
} ^F:Bj&0v[  
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Utility.log("Thread " + nThreadID + " is over!"); .vWwYG  
bDownOver = true; >m#bj^F\  
//nPos = fileAccessI.write (b,0,nRead); 9#b/D&pX5  
} ^b^}6L'Z  
catch(Exception e){e.printStackTrace ();} ]1&}L^a  
} 9N V.<&~  
} M}x]\#MMY  
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//打印回应的头信息 2+cpNk$  
public void logResponseHead(HttpURLConnection con) a<CACWsN.T  
{ 5`p>BJ+n  
for(int i=1;;i++) d34BJ<  
{ HMq
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String header=con.getHeaderFieldKey(i); ^wxpinJ>  
if(header!=null) }0~X)Vgm(  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2VaKt4+`  
Utility.log(header+" : "+con.getHeaderField(header)); qA5 Ug  
else ^/fasl$#  
break; Er@OmNT  
} jchq\q)_z  
} {pk]p~  
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public void splitterStop() O#?@'1  
{ IA680^  
bStop = true; VCQo3k5 {  
} tQ(4UHqa~  
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} 6QAhVg: A  
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/* a6!|#rt  
**FileAccess.java t4Pi <m:7  
*//文件访问(定位，写) D`3`5.b  
package NetFox; FA!!S`{\  
import java.io.*; ()e|BFL.  
&gsBbQ+qA  
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public class FileAccessI implements Serializable{ /X%+z5  
OTzuOP8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 u7lO2C7  
RandomAccessFile oSavedFile; k8z1AP  
long nPos; -{A*`.[v  
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p} {H%L  
public FileAccessI() throws IOException f"SK3hI$p  
{ <.hutU*1  
this("",0); q![`3m-d.  
} CaR-Yk   

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public FileAccessI(String sName,long nPos) throws IOException V6Y0#sTU  
{ CD[}|N  
oSavedFile = new RandomAccessFile(sName,"rw"); (nAL;:$x2  
this.nPos = nPos; <nc6&+  
oSavedFile.seek(nPos); vwAtX($  
} Q)=LbR{#  
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public synchronized int write(byte[] b,int nStart,int nLen) mM.YZUX  
{ Ug\$Ob5=q  
int n = -1; XIn,nCY;  
try{ %Ni"*\  
oSavedFile.write(b,nStart,nLen); oI-,6G}
 
n = nLen; 33g$mUB  
}  "3/&<0k  
catch(IOException e) wKKQAM6P1  
{ P1ak>T*#2  
e.printStackTrace (); 5bBCI\&sam  
} yxAy1P;dX  
E
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return n; 3~:9ZWQ/  
} N-W>tng_x  
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} Kc,i$FH  
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/* aK/fZ$Qc  
**SiteInfoBean.java ")<5VtV  
*/ /36gf  
package NetFox; %j.n^7i]^:  
I-#7Oq:Np  
)D ~ 5  
public class SiteInfoBean { K&eT*JW>  
aYn5AP'PH  
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private String sSiteURL; //Site's URL Zz"8  
private String sFilePath; //Saved File's Path EjMVlZC>  
private String sFileName; //Saved File's Name m`}mbm^  
private int nSplitter; //Count of Splited Downloading File 5Dzf[V^]`  
$ ^@fV=e  
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public SiteInfoBean() D -d  
{//nSplitter的缺省值为5 x#gZC
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//default value of nSplitter is 5 kc(m.k!|f\  
this("","","",5); hfw+n<  
} QiK-|hFj  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }x+6<Rp'E_  
{ IqiU  
sSiteURL= sURL; )/)[}wN;j  
sFilePath = sPath; x"!`JDsS  
sFileName = sName; BoxtP<C"  
this.nSplitter = nSpiltter; Jy\0
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} &>&6OV]P'  
[!4xInS  
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public String getSSiteURL() "YaT1`Kr  
{ t<ZBp0  
return sSiteURL; ;dPaWS1D  
} U!NuiKaQ26  
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public void setSSiteURL(String value) XwFTAaZ  
{ .]s? 01Z  
sSiteURL = value; >]8(3&zd  
} s1h
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RMiDV^.u`  
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public String getSFilePath() I=:"Fqj'N  
{ drc-5{M  
return sFilePath; TW!OE"B  
} tGU~G&  
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public void setSFilePath(String value) / g{8  
{ _VVq&t}  
sFilePath = value; _",<at  
} l i)6^f#  
L""ZI5J{F9  
J]#rh5um  
public String getSFileName() Z,O*p,Gzn  
{ FzcXSKHV%  
return sFileName; 0|.jIix;  
} ^b$_I31D  
(qvH=VTwP  
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public void setSFileName(String value) BGxwPJd  
{ Rk7F;2  
sFileName = value; .{\eco  
} qdn_ZE  
xT]t3'y|-  
yo/;@}g}  
public int getNSplitter() g'b|[ q  
{ K4jHha  
return nSplitter; &a=78Z  
} yQMwt|C4  
"[!b5f3!I  
'tY(&&  
public void setNSplitter(int nCount) +<.o,3  
{ Z|Oq7wzEH  
nSplitter = nCount; T- _))  
} rhcax%
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} 5a'`%b{{  
NLK1IH#  
T[)!7@4r  
/* jLM([t  
**Utility.java l)*(UZ"  
*/ |Q%P4S"B?  
package NetFox; V:'F_/&X?  
q)L4*O  

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public class Utility { icIn>i<m  
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public Utility() bXvO+I<  
{
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} )ds]fvMW]N  
:ujpLIjvVG  
//线程睡眠 :CW^$Zvq  
public static void sleep(int nSecond) ""jW'%wR  
{ ^!\AT!
OT  
try{ Yi?bY  
Thread.sleep(nSecond); @;`'s  
} +/Y2\s  
catch(Exception e) S'8+jY  
{ +^+'.xQ  
e.printStackTrace (); \c4jGJ  
} Q5T3  
} RSh_~qMX  
OPDT:e86Y=  
//日志 zmGHI!tP  
public static void log(String sMsg) n|)((W  
{ %K4M`R|2]  
System.err.println(sMsg); R|$AcNp  
} p|.5;)%|  
\.}T_,I  
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public static void log(int sMsg) V%s7*`U  
{ )f|`mM4DW!  
System.err.println(sMsg); WM?-BIlT=  
} W/bW=.d Jd  
} - [h[  
#i@f%Bq-  
TDDMx |{  
/* yy=hCjQ)  
**TestMethod.java $ mE*=  
*/ U
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package NetFox; ];hqI O#nM  
TLVsTM8P  
t&?{+?p: 9  
public class TestMethod { /]3[|  
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2I [zV7 @t  
public TestMethod() ` = O  
{ ///xx/weblogic60b2_win.exe wQUl!s7M;  
try{ &&9|;0<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IZj`*M%3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); olv?$]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); iW(LD1~7  
fileFetch.start(); .)b<cH~%  
} (cOe*>L;  
catch(Exception e){e.printStackTrace ();} |Q
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} }6%XiP|  
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9=ygkPY  
public static void main(String[] args) $ ubU"  
{ IU"  
new TestMethod(); MGm*({%  
} 7-K8u  
} mG\QF0h  
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