http断点续传简单实现（java)

/* TE9Iyl|=  
**SiteFileFetch.java c6T[2Ig  
*/ eg1Mdg\a  
package NetFox; R>t?6HOcp  
import java.io.*; Itz[%Dbiq9  
import java.net.*; YuUJgt .1  
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public class SiteFileFetch extends Thread { /|p\l"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean eiQ42x@Z  
long[] nStartPos; //开始位置 IP
  
long[] nEndPos; //结束位置 ,MjlA{0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 '2Lx>nByk  
long nFileLength; //文件长度 m}(M{^\|  
boolean bFirst = true; //是否第一次取文件 DkEf;P  
boolean bStop = false; //停止标志 - -\eYVh[  
File tmpFile; //文件下载的临时信息 qjsEyro$-  
DataOutputStream output; //输出到文件的输出流 " ?Ux\)*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _;,"!'R`f  
public SiteFileFetch(SiteInfoBean bean) throws IOException Iw4[D#o  
{ T#\=v(_NR  
siteInfoBean = bean; H]}mg='kI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); mX%T"_^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); pr[V*C/  
if(tmpFile.exists ()) -(},%!-_  
{ }9V0Cu1  
bFirst = false; Nwo*tb:  
read_nPos(); +|--}iE
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} X%$1%)C9  
else Zb7%$1)L~  
{ p}Um+I=1  
nStartPos = new long[bean.getNSplitter()]; H;seT X
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nEndPos = new long[bean.getNSplitter()]; Qv<p$Up6  
} `MHixQ;j  
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}9 ]7V<  
} IF cre  
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public void run() z(u,$vZ_  
{ o:B?hr'\  
//获得文件长度 &]tm'N25  
//分割文件 Xf[;^?]X  
//实例FileSplitterFetch nsM.`s@V  
//启动FileSplitterFetch线程 %d%FI"!K  
//等待子线程返回 *'*,mfk[  
try{ ;9Qxq]
 
if(bFirst) "(iDUl  
{ / */"gz%  
nFileLength = getFileSize(); #iQF)x| D  
if(nFileLength == -1) /BN=Kl]  
{
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System.err.println("File Length is not known!"); icQQLSU5  
}
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else if(nFileLength == -2) I/%L,XyRI  
{ !ALq
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System.err.println("File is not access!"); O6,2M[a  
} e=s({V  
else F|G v  
{ 9I:3  
for(int i=0;i<nStartPos.length;i++) 3mHP=)  
{ G?,"AA;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); O)ose?Z  
} AV4fN@BX  
for(int i=0;i<nEndPos.length-1;i++) +4p=a [  
{ * H~=
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nEndPos = nStartPos[i+1]; [%P[ x]-  
} :*/g~y(fE  
nEndPos[nEndPos.length-1] = nFileLength; ^
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} A9KPU:  
} Qp7F3,/#  
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//启动子线程 YhzDw8f  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; AiL80W^=d)  
for(int i=0;i<nStartPos.length;i++) v0TbQ  
{ >
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }]M'f:%b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),
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nStartPos,nEndPos,i); %O!TS_~9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kT]jJbb"  
fileSplitterFetch.start(); ]0O3kiVQ  
} &grvlK  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j;qV+Rq]t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", VT-%o7%N  
nEndPos = " + nFileLength); Dc* H:x;  
// fileSplitterFetch[nPos.length-1].start(); D+jE{v'  
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//等待子线程结束 ?~IdPSY  
//int count = 0; ^QjkZ^<dD  
//是否结束while循环 4e?bkC  
boolean breakWhile = false; H DD)AM&p  
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while(!bStop) `A
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{ CbXSJDs  
write_nPos(); M6 8foeeN  
Utility.sleep(500); 7<=p*  
breakWhile = true; <CJy3<$u  
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for(int i=0;i<nStartPos.length;i++) y(/5l  
{ =c
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if(!fileSplitterFetch.bDownOver) Q/]o'_[vW  
{ sxS%1hp3  
breakWhile = false; a#G3dY>  
break; Pd& Npp3  
} R^=v&c{@  
} ay||yn:  
if(breakWhile) W8Wjq DQ  
break; I(WIT=Wi<  
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//count++; @nMVs6  
//if(count>4) 2s>BNWTU  
// siteStop(); ^7*7^<  
} MslgQmlM  
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System.err.println("文件下载结束！"); f& \Bs8la  
} lFduX D  
catch(Exception e){e.printStackTrace ();} m`n~-_  
} /2hRLyeAZ  
Q&+)Kp]A  
FC~%G&K/q^  
//获得文件长度 FV3[
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public long getFileSize() fYzP4  
{ X$@qs9?)^  
int nFileLength = -1; 00s)=A_  
try{ XPZ8*8JL  
URL url = new URL(siteInfoBean.getSSiteURL()); k.jBu  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Rry]6(  
httpConnection.setRequestProperty("User-Agent","NetFox"); -rjQ^ze  
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/u_9uJ"-K(  
int responseCode=httpConnection.getResponseCode(); l]#=I7 6  
if(responseCode>=400) l!KPgRw  
{ kj.9\  
processErrorCode(responseCode); ?FUK_]  
return -2; //-2 represent access is error _<DOA:'v  
} 6`G8UDK>F  
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4e;$+!dlV  
String sHeader; %3|
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}N).$  
for(int i=1;;i++) TI<3>R  
{ 2_6ON   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h:U#F )  
//Utility.log(in.readLine()); aG]^8`~>'  
sHeader=httpConnection.getHeaderFieldKey(i); 1Sza%D;3  
if(sHeader!=null) v`jHd*&6)  
{ >T\@j\X4  
if(sHeader.equals("Content-Length")) IbJl/N%o  
{ s$(%?,yf2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >dJ~  
break; $+ N~Fa  
} Lfdg5D5.P  
} ij~-  
else S0gxVd(  
break; +Mhk<A[s  
} %W2U$I5  
} "vQ%` Q  
catch(IOException e){e.printStackTrace ();} RLL%l  
catch(Exception e){e.printStackTrace ();} Z h9D^I  
LH=^3Gw  
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Utility.log(nFileLength); ?Yf v^DQ5  
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return nFileLength; $$W2{vr7+  
} PB.'huu  
7fO<=ei:  
L<3+D
 
//保存下载信息（文件指针位置） MxT&@pq  
private void write_nPos() oyY z3X  
{ INp:;  
try{ `4X.UPJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U<q`f-  
output.writeInt(nStartPos.length); &Td)2Wt  
for(int i=0;i<nStartPos.length;i++) c3ru
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{ ~e]B[>PT  
// output.writeLong(nPos); }&v-<qC^  
output.writeLong(fileSplitterFetch.nStartPos); HwZl"!;Mry  
output.writeLong(fileSplitterFetch.nEndPos); HC1<zW[  
} ^k$Bx_{  
output.close(); O6 s3#iu  
} b SgbvnJ  
catch(IOException e){e.printStackTrace ();} ~k?wnw
 
catch(Exception e){e.printStackTrace ();} /':64#'  
} /'E[03I~  
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#gT"G1
8/!  
//读取保存的下载信息（文件指针位置） NWPT89@l  
private void read_nPos() ?6nB=B)/  
{ QT73=>^B  
try{ =Ry8E2NuM  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Fj2z$  
int nCount = input.readInt(); cQ1Axs TO  
nStartPos = new long[nCount]; -$:*!55:j  
nEndPos = new long[nCount]; a~a:mM>p  
for(int i=0;i<nStartPos.length;i++) L-S5@;"  
{ 2 'D,1F  
nStartPos = input.readLong(); |r,})o>  
nEndPos = input.readLong(); x{zZ%_F  
} YcclO  
input.close(); vM!2?8bEFd  
} XzX2V">(%  
catch(IOException e){e.printStackTrace ();} 5#N<~  
catch(Exception e){e.printStackTrace ();} +>;Ux1'@  
} |e+3d3T35  
!L q'o?  
"\
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private void processErrorCode(int nErrorCode) V_D wHq2  
{ DTM(SN8R+n  
System.err.println("Error Code : " + nErrorCode); Lk@+iHf  
} a#%*H
 
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83 R_8  
//停止文件下载 ZWGX*F#}P  
public void siteStop() (VI(Nv:o@  
{ Jr;w>8B),  
bStop = true; wbcip8<t  
for(int i=0;i<nStartPos.length;i++) n'{jc6&|  
fileSplitterFetch.splitterStop(); x=L"qC9f/  
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} &~/g[\Y  
} 2RF3pIFrm  
//负责部分文件的抓取 LklE,W  
**FileSplitterFetch.java ]v),[]Xs  
*/ W2h4ej\s  
package NetFox; m9MYd  
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import java.io.*; tjB)-=j[  
import java.net.*; t?)]xS)  
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public class FileSplitterFetch extends Thread { R@5eHP^  
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AB,(%JT/2{  
String sURL; //File URL s-'~t#h  
long nStartPos; //File Snippet Start Position EA1&D^nT  
long nEndPos; //File Snippet End Position ss}-YnG  
int nThreadID; //Thread's ID 4g2`[<S  
boolean bDownOver = false; //Downing is over Rx"+i0  
boolean bStop = false; //Stop identical $6J22m!S4n  
FileAccessI fileAccessI = null; //File Access interface lxgfi@@+h  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s5+;8u9K  
{ ~vA8I#.  
this.sURL = sURL; KU{zzn;g  
this.nStartPos = nStart; f{O-\
 
this.nEndPos = nEnd; KehM.c^  
nThreadID = id; zDt
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 SFtcO  
} (G} }h  
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public void run() a?GXVQ  
{ =-/'$7R,  
while(nStartPos < nEndPos && !bStop) {dxl8~/I  
{ H Q[  
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try{ .bP8Z=  
URL url = new URL(sURL); e&:%Rr]x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L'`Au/%S}  
httpConnection.setRequestProperty("User-Agent","NetFox"); L
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String sProperty = "bytes="+nStartPos+"-"; 4:Ju|g]O  
httpConnection.setRequestProperty("RANGE",sProperty); :k`Qj(7S  
Utility.log(sProperty); \>wQyz  
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InputStream input = httpConnection.getInputStream(); WHOy\j},V  
//logResponseHead(httpConnection); %g5#q64  
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byte[] b = new byte[1024]; lDKyD`WKnZ  
int nRead;
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?f3R+4  
{ B=%%3V)2  
nStartPos += fileAccessI.write(b,0,nRead); C{nk,j L  
//if(nThreadID == 1) J1cz D|(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u*5}c7)uId  
} 4|5;nxkGm8  
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Utility.log("Thread " + nThreadID + " is over!"); !t~tIJ>6  
bDownOver = true; L aA<`  
//nPos = fileAccessI.write (b,0,nRead); Hhk`yX c_  
} s?S e]?i  
catch(Exception e){e.printStackTrace ();} yX{7<\x   
} <o3I<ci6  
} FJ!`[.t1AU  
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//打印回应的头信息 sUmpf4/  
public void logResponseHead(HttpURLConnection con) ,?qJAV~>  
{ ]}l.*v\uK  
for(int i=1;;i++) j1->w8  
{ W+=j@JY}q9  
String header=con.getHeaderFieldKey(i); n{~&^Nby*I  
if(header!=null) {jR3D!hK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); jr.{M  
Utility.log(header+" : "+con.getHeaderField(header)); d_&pxy? >  
else o+{i26%  
break; s 72y
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} &FOq c  
} /y
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public void splitterStop() VyYrL]OrA  
{ $6 Hf[(/e  
bStop = true; t.RDS2N|  
} c2
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} lFcHE c  
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/* l:u1P  
**FileAccess.java IDqUiN  
*//文件访问(定位，写) S5F5Tr;TN  
package NetFox; {2 T:4i5  
import java.io.*; F=*t]X[z}  
#hs&)6Sf  
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public class FileAccessI implements Serializable{ N.]~%)K:{  
Yc~lYz+b  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z(O*DwY#  
RandomAccessFile oSavedFile; *0L3#. i  
long nPos; `}uM91;  
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public FileAccessI() throws IOException .8ikcs  
{ ^!k_"C)B  
this("",0); H=WB6~8)  
} ?5lO1(  
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public FileAccessI(String sName,long nPos) throws IOException ?*kB>U9e  
{ Er$&}9G+-  
oSavedFile = new RandomAccessFile(sName,"rw"); yLXIjR  
this.nPos = nPos; Xq37:
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oSavedFile.seek(nPos); /4+zT
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} I~p*~mLh'  
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public synchronized int write(byte[] b,int nStart,int nLen) n4XkhY|  
{ s-x1<+E(  
int n = -1;
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try{ 9PO5GYU  
oSavedFile.write(b,nStart,nLen); jY/(kA]}  
n = nLen; qQo*:3/];  
} yU7XX+cB7  
catch(IOException e) ND=JpVkvZ?  
{ 'zMmJl}\vd  
e.printStackTrace (); F/tRyq`D  
} Wie0r@5E  
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return n; gw
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} j1K~zG  
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} 3&c'3y:b  
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}> C?Zx*  
/* t)k;5B`> &  
**SiteInfoBean.java egfd=z=2un  
*/ 4PU@W o  
package NetFox; D0S^Msk9L  
~WV1t][  
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public class SiteInfoBean { "OkZ [E)  
ix?Z:pIS0  
rXTdhw?+  
private String sSiteURL; //Site's URL "av/a  
private String sFilePath; //Saved File's Path e9S*^2;  
private String sFileName; //Saved File's Name \fUVWXv  
private int nSplitter; //Count of Splited Downloading File ab)ckRC  
r,vSDHb`j  
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public SiteInfoBean() KlBT9"6"  
{//nSplitter的缺省值为5 l#+@!2z  
//default value of nSplitter is 5 |r+hj<K  
this("","","",5); i \lr KA  
} l#>A.-R*`  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Sv>CVp*  
{ PIQd=%?'  
sSiteURL= sURL; qla=LS\-A+  
sFilePath = sPath; yC|odX#  
sFileName = sName; w`#9Re  
this.nSplitter = nSpiltter; UA0( cK  
k4:=y9`R}$  
bsI?=lO  
} YVz,P_\(m  
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public String getSSiteURL() (0?FZ.9%  
{ 2U+Fat@  
return sSiteURL; 'q8:1i9\[  
} %/s+-j@s:  
H6$pA^  
_R ;$tG,  
public void setSSiteURL(String value) =3;! 5P  
{ `VglE?M  
sSiteURL = value; ?$/W3Xn0%  
} w0<1=;_%  
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public String getSFilePath() #Wv8+&n  
{ uBM%E OE  
return sFilePath; 4QNwu7TeR  
} 4!'4 l=jO  
kO/;lrwC  
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public void setSFilePath(String value) /" &Jf}r  
{ \C1`F[d_  
sFilePath = value; V`feUFw3  
} a'my0m  
Q b5vyV `  
$KGRpI  
public String getSFileName() #_Lg
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{ 5'(#Sf
 
return sFileName; WO+>W+|N  
} (|y@ftr@  
`
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public void setSFileName(String value) DPl&e-`  
{ _]+ \ B  
sFileName = value; *zX^Sg-[  
} jH9.N4L  
P&Hhq>@Z  
vFgnbWxG  
public int getNSplitter() bGp3V. H  
{ 7zXX& S  
return nSplitter; h~&5;  
} DwXSlsN3v  
7 /DDQ  
>?$q
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public void setNSplitter(int nCount) Bjb8#n04  
{ BUla2p  
nSplitter = nCount; 95tHire  
} :YmFQ>e?  
} 9NC'iFQ#  
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/* m&6)Vt  
**Utility.java P;p20+  
*/ TaTw,K|/  
package NetFox; U {sT %G  
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public class Utility { $-mwr,i  
6 &MATMR  
W -5wjc  
public Utility() R%r<AL5kJk  
{ L'x[wM0w;  
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} 9M .cTIO{  
m'L8z fX  
//线程睡眠 XSo$;q\  
public static void sleep(int nSecond) |%Ssb;M  
{ Ky[-ZQQo=5  
try{ <
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Thread.sleep(nSecond); *W1:AGpz  
} e5m-7{h@  
catch(Exception e) d@<~u,Mt&F  
{ CDRz3Hu U  
e.printStackTrace (); !}&f2!?.W  
} ^36m$J$  
} 0BHSeO,  
]}N&I_mU  
//日志 ZG-[Gz  
public static void log(String sMsg) ZfWF2%]<  
{ X}j_k=,C  
System.err.println(sMsg); 0tah$;c e  
} }!5+G:JAh  
]1i1_AR'`  
XZ1<sm8t."  
public static void log(int sMsg) UP e@>  
{ &^b mZj!  
System.err.println(sMsg); An3%@;  
} 9]*hP](  
} 7V7iIbi  
(n~GKcA  
t3FfPV!P"  
/* bl`vT3  
**TestMethod.java >{w"aJ" F  
*/ Eza B}BLQ9  
package NetFox; CB%O8d #  
p?4h2`P  
+Zo&c}  
public class TestMethod { uSn<]OrZo`  
<S`N9a  
$_0~Jzt,  
public TestMethod() ]$ iqJL  
{ ///xx/weblogic60b2_win.exe ; Uf]-uS  
try{ >KnXj7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]tDuCZA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?Y#x`DMh  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a2`|6M;  
fileFetch.start(); jM|-(Es.)  
} d"hW45L  
catch(Exception e){e.printStackTrace ();} hS7o=G[  
-PH!U Hg  
2ID]it\5  
} H+2m  
t"L-9kCM  
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public static void main(String[] args) *u`[2xmuYf  
{ o+.LG($+U  
new TestMethod(); >$iQDVh!  
} j692M.A  
} xr'gi(.o  
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