http断点续传简单实现（java)

/* m7~[f7U  
**SiteFileFetch.java M)!:o/!cS  
*/ od~`q4p1(-  
package NetFox; js8\"  
import java.io.*; 7Om)uUjU4  
import java.net.*; P;
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public class SiteFileFetch extends Thread { 05m/iQ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean cP MUu9du  
long[] nStartPos; //开始位置 UT7"
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long[] nEndPos; //结束位置 &tw   
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =rDIU&0Y  
long nFileLength; //文件长度 u(|k/~\  
boolean bFirst = true; //是否第一次取文件 )SYZ*=ezl.  
boolean bStop = false; //停止标志 ;j/-
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File tmpFile; //文件下载的临时信息 )04lf*ti  
DataOutputStream output; //输出到文件的输出流 ';?b99  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） O[fg
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public SiteFileFetch(SiteInfoBean bean) throws IOException ]]Da/^K=Z  
{ eX>X=Ku  
siteInfoBean = bean; JSQ*8wDcl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .o5r;KD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); tr\Vr;zd  
if(tmpFile.exists ()) !j.jvI%e;  
{ ;.r >  
bFirst = false; g$*VA} s  
read_nPos(); zorTZ #5  
} 7a:mZ[Vh  
else ;{~F7:i  
{ 
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nStartPos = new long[bean.getNSplitter()]; ;zO(bj>  
nEndPos = new long[bean.getNSplitter()]; >AW=N  
} hrRX=  
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} 3f:I<S7  
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public void run() YA>du=6y\  
{ ^50/.Z>  
//获得文件长度 ;pNHT*>u,  
//分割文件 $|YIr7?R  
//实例FileSplitterFetch _k@{> ?(a  
//启动FileSplitterFetch线程 Q(KLx)  
//等待子线程返回 0fPqO2  
try{ 5i$~1ZC  
if(bFirst) 41TB  
{ 9c=_p'G3Fw  
nFileLength = getFileSize(); K/u`Wz~A  
if(nFileLength == -1) WLWE%bDP  
{ ?WX&,ew~  
System.err.println("File Length is not known!"); Zh.fv-Ecp  
} BKm$H!u  
else if(nFileLength == -2) O/\jkF  
{ ?fEX&t,'  
System.err.println("File is not access!"); 2eu`X2IBcT  
} [hS?d.D   
else 8E Y<^:  
{ 5b[:B~J  
for(int i=0;i<nStartPos.length;i++) aM9St!i  
{ O.E  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `B6{y9J6  
} rQ'tab.,]  
for(int i=0;i<nEndPos.length-1;i++) G1~|$X@@  
{ k[
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nEndPos = nStartPos[i+1]; 8Db~OYVJG  
} bhSpSul  
nEndPos[nEndPos.length-1] = nFileLength; <P5;8  
} q9oF8&O,  
} Co19^g*  
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//启动子线程 H9w*U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; g}3c r.  
for(int i=0;i<nStartPos.length;i++) *ma/_rjK  
{ Em@h5V  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K.R2)o`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }FMl4 _}u  
nStartPos,nEndPos,i); [JVI@1T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,/W<E  
fileSplitterFetch.start(); lr
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} fu=}E5ScK  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tTyu,%/m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .KT+,Y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", AEnS_Q  
nEndPos = " + nFileLength); ja7Zv[  
// fileSplitterFetch[nPos.length-1].start(); :<&}/r  
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//等待子线程结束 _T5~B"*  
//int count = 0; d!KX.K\NM,  
//是否结束while循环 BdO$  
boolean breakWhile = false; &J hN&Ur  
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while(!bStop) 9v cUo?
/  
{ |k/;
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write_nPos(); \Zf&&7v  
Utility.sleep(500); Ip4NkUI3T  
breakWhile = true; #4//2N  
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for(int i=0;i<nStartPos.length;i++) E}@8sY L  
{ pN0c'COy^  
if(!fileSplitterFetch.bDownOver) : 1fik  
{ d<7J)zUm3  
breakWhile = false; +H&_Z38n  
break; i8B%|[nm  
} 2J4|7UwJ  
} _;B!6cRLps  
if(breakWhile) fr#lH3  
break; `8dE8:#Y  
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//count++; eN> (I
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//if(count>4) >>$IHz4Z"  
// siteStop(); RaU.yCYyu  
} ){YPP!8cI  
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System.err.println("文件下载结束！"); iQ9#gPk_9  
} uAj

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catch(Exception e){e.printStackTrace ();} <Z m ,q}  
} gv[7h'}<  
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"j a0,%3  
//获得文件长度 ZHC sv]l  
public long getFileSize() [QZ~~(R  
{ 2/7=@>|  
int nFileLength = -1; %o"Rcw|  
try{ 9uS7G*  
URL url = new URL(siteInfoBean.getSSiteURL()); gs8L/veP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ox~'w0c,f  
httpConnection.setRequestProperty("User-Agent","NetFox"); Tc88U8Gc  
_).'SU)>  
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int responseCode=httpConnection.getResponseCode(); 'hekCZZ_I  
if(responseCode>=400) ?Nh%!2n  
{ s3+O
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processErrorCode(responseCode); gw*d"~A  
return -2; //-2 represent access is error Xl/G|jB9  
} f0D Ch]  
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String sHeader; 4*+EUJ|  
7
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for(int i=1;;i++) }a9C/t3  
{ p_z"Uwp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); sRZ:9de+  
//Utility.log(in.readLine()); YjX=@  
sHeader=httpConnection.getHeaderFieldKey(i); 42wcpSp  
if(sHeader!=null) Mb>6.l  
{ 5pok%g  
if(sHeader.equals("Content-Length")) *[SsvlFt  
{ H*\[:tPa  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )2FO+_K?T  
break; tH'VV-!MZ  
} poeXi\e!(  
} OpL6Y+<  
else w//w$}v  
break; }=|ZEhtOp  
} -1_Z*?
=-  
} {cv;S2  
catch(IOException e){e.printStackTrace ();} _#gsR"FZ$  
catch(Exception e){e.printStackTrace ();} bY2Mw8e%  
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Utility.log(nFileLength); `{wku@  
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return nFileLength; $0
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} MzG ryM-  
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//保存下载信息（文件指针位置） m4DH90~a8  
private void write_nPos() *h4m<\^U  
{ h]Oplp4\W  
try{ Q'a N|^w"f  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1ZL_;k  
output.writeInt(nStartPos.length); fv_wK_. %:  
for(int i=0;i<nStartPos.length;i++) Dgm%Ng  
{ 84!4Vz^  
// output.writeLong(nPos); SNU bY6  
output.writeLong(fileSplitterFetch.nStartPos); AY;+Ws  
output.writeLong(fileSplitterFetch.nEndPos); v 2GhR*  
} ^<VE5OM  
output.close(); z`5I1#PVA  
} Ozv.;}SE  
catch(IOException e){e.printStackTrace ();} ]-'9|N*}l  
catch(Exception e){e.printStackTrace ();} S1zw'!O5  
} S<_pGz$V  
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//读取保存的下载信息（文件指针位置） I.u,f:Fl'  
private void read_nPos() 3rY /6{  
{ Mak9qaWqF>  
try{ >>bYg  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _cw^5  
int nCount = input.readInt(); kVrT?  
nStartPos = new long[nCount]; +2}(]J=-  
nEndPos = new long[nCount]; ,&?q}M  
for(int i=0;i<nStartPos.length;i++) | q16%6q  
{ \z`d}\3(R  
nStartPos = input.readLong(); b(q&}60  
nEndPos = input.readLong(); J\so8uT:  
} qE72(#:R*  
input.close(); -HsBV>C  
} DP_Pqn8p&M  
catch(IOException e){e.printStackTrace ();} iFCH$!  
catch(Exception e){e.printStackTrace ();} (<C%5x
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} 6h_k`z  
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private void processErrorCode(int nErrorCode) R{o*O_qX  
{ 0o|,& K  
System.err.println("Error Code : " + nErrorCode); _A|\.(t  
} g$"eI/o  
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//停止文件下载 ,;P`Mf'YC  
public void siteStop() e-cb?.WU?  
{ gwaC?tf[  
bStop = true; &8AS=v  
for(int i=0;i<nStartPos.length;i++) >
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fileSplitterFetch.splitterStop(); thPH_DW>eb  
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} 4D8yb|o  
} (I[h.\%  
//负责部分文件的抓取 A]?O&m|  
**FileSplitterFetch.java c;rp@_ULG?  
*/ 7oe@bS/Z  
package NetFox; M y"!j,Up  
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import java.io.*; gZEA;N:H%<  
import java.net.*; DVoV:pk  
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public class FileSplitterFetch extends Thread { Z)O>h^0  
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String sURL; //File URL T:S
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long nStartPos; //File Snippet Start Position uP=_-ZUW  
long nEndPos; //File Snippet End Position ,q@(L  
int nThreadID; //Thread's ID &/hr-5k  
boolean bDownOver = false; //Downing is over ar qLp|  
boolean bStop = false; //Stop identical y[WYH5&DJ  
FileAccessI fileAccessI = null; //File Access interface
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException txfwLqx  
{ Pv-V7`{  
this.sURL = sURL; :y-0qzD?  
this.nStartPos = nStart; mERZ_[a2  
this.nEndPos = nEnd;  mz VuQ  
nThreadID = id; A[ECa{v  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2V2x,!  
} "">fn(  
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public void run() LYy:IBI7_  
{ T3t~=b>&L  
while(nStartPos < nEndPos && !bStop) )Kk(P/s  
{ Fma`Cm.  
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try{ H=o-ScA  
URL url = new URL(sURL); \eMYw7y5M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J]Gc  
httpConnection.setRequestProperty("User-Agent","NetFox"); tD~PvUJ  
String sProperty = "bytes="+nStartPos+"-"; 4}8+)Pd  
httpConnection.setRequestProperty("RANGE",sProperty); p-yOiG8b}  
Utility.log(sProperty); a,57`Ks+n<  
>,"D9!  
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InputStream input = httpConnection.getInputStream();  `\|3 ~_v  
//logResponseHead(httpConnection); `/wq3+?  
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byte[] b = new byte[1024]; H8<7#
 
int nRead; :&1=8^BY  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) rGn5Q
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{ %hQM
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nStartPos += fileAccessI.write(b,0,nRead); kk/+Vx~  
//if(nThreadID == 1) %j[LRY/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nhQ44qRgQ  
} AeY$.
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! F;<xgw  
Utility.log("Thread " + nThreadID + " is over!"); =wlm  
bDownOver = true; o9T@uWh+  
//nPos = fileAccessI.write (b,0,nRead); \+?,c\x  
} S1az3VJI\  
catch(Exception e){e.printStackTrace ();} 8MeO U  
} r8 Zyld_@  
} x^#6>oOR  
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//打印回应的头信息 "x.6W!  
public void logResponseHead(HttpURLConnection con) ~^%0V<*-}  
{ K?FX<PT  
for(int i=1;;i++) [aWDD[#j~  
{ 5&-j{J0iV  
String header=con.getHeaderFieldKey(i); T[4[/n>i  
if(header!=null) =!g/2;-or  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ph8Jn
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Utility.log(header+" : "+con.getHeaderField(header)); |?2 hml  
else {7K'
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break; oc3dd"8}@  
} l6S19Kv  
} BDm88<]  
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public void splitterStop() GTp?)nh^  
{ ^EC)~HP@C  
bStop = true; `bZ2x
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} :tjgg]  
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}  d-ag  
un$ Z7W/  
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/* GCP{Z]u  
**FileAccess.java [xZ/ZWb/  
*//文件访问(定位，写) SG dfhno;  
package NetFox; y~==waZw  
import java.io.*; 2,8/Cb  
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public class FileAccessI implements Serializable{ WA]%,6  
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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 P0'e"\$  
RandomAccessFile oSavedFile; H})Dcg3  
long nPos; i14[3bPLk!  
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public FileAccessI() throws IOException \A'|XdQ  
{ /-
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this("",0); SE,o7_k'S  
} H )BOSZD  
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public FileAccessI(String sName,long nPos) throws IOException )(:+q(m  
{ 4|zdXS  
oSavedFile = new RandomAccessFile(sName,"rw"); b(PHZCy#  
this.nPos = nPos; 9SRfjS{7  
oSavedFile.seek(nPos); u(V  
} [K/O5_  
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public synchronized int write(byte[] b,int nStart,int nLen) 4 [R8(U[g  
{ RLYU\@kK?  
int n = -1; 18
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try{ sBP}n.#$  
oSavedFile.write(b,nStart,nLen); _o@(wGeu#  
n = nLen; G$?|S@I,  
} 4zo4H~@gk  
catch(IOException e) ~q0I7M  
{ ?1GY%-  
e.printStackTrace (); ^lHb&\X  
} 1fz*SIjG  
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return n; BA~a?"HS  
} g".d"d{  
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} +3M$3w{2  
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/* nc3sty1`  
**SiteInfoBean.java ES^>[2Y  
*/ ;j>*;Q`  
package NetFox; 0lX)Cl  
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public class SiteInfoBean { Uby,Tu  
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private String sSiteURL; //Site's URL C>*5=p|T  
private String sFilePath; //Saved File's Path 6-mmi7IfO  
private String sFileName; //Saved File's Name |ZS 57c:  
private int nSplitter; //Count of Splited Downloading File 7%{R#$F  
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public SiteInfoBean() ( MB`hk-d  
{//nSplitter的缺省值为5 M (+.$uz  
//default value of nSplitter is 5 o .l;: Un  
this("","","",5); p]wP36<S!  
} /SnynZ.q  
mgy"|\]  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) T#\p%w9d  
{ (7IqY1W  
sSiteURL= sURL; <A)+|Y"^h6  
sFilePath = sPath; 6!ZVd#OM%  
sFileName = sName; \.c]kG>k-  
this.nSplitter = nSpiltter; M6J/mOVx5  
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,5/V@;i  
} y)6,0K {k  
i\(\MzW*'  
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public String getSSiteURL() PKi_Zh.D  
{ GtF2@\  
return sSiteURL; Z`rK\Bc  
} >4,{6<|  
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public void setSSiteURL(String value) L'>s(CR  
{ 1<`
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sSiteURL = value; w|=gSC-o  
} N6h1|
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public String getSFilePath() mKV'jm0  
{ 1xz\=HOT  
return sFilePath; [_h%F,_ A  
} gF3TwA
r  
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B]1HS`*7  
public void setSFilePath(String value) x"vwWJN
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{ z+jh;!i  
sFilePath = value; tG/1p

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} wa" uFW  
NUMi])HkN  
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public String getSFileName() WE")xhV6  
{ )%s +?  
return sFileName; B#]_8svO  
} tVunh3-  
:y\09)CJK  
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public void setSFileName(String value) I0DM=V>;  
{ hm3jpWi8  
sFileName = value; vVAb'`ysv  
} 7$ d}!S  
cS}r9gaQ  
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public int getNSplitter() 6^sHgYR  
{ e&2wdH&  
return nSplitter; J/t!-!  
} }w@gj"\H  
MD<-w|#8IV  
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public void setNSplitter(int nCount) +3Y!xD?=  
{ W}h|K:-S  
nSplitter = nCount; X/Y#U\  
} GQx9u^>  
} 0qv$:w)g+v  
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/* -u|l}}b
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**Utility.java O6iCZ  
*/ ~s#e,Kav"  
package NetFox; X2gz6|WJ  
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public class Utility { B;!f<"a8  
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public Utility() Sj)}qM-y#  
{ [Uli>/%JB  
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} YUscz!rM  
2zK"*7b?  
//线程睡眠 &x0C4Kh  
public static void sleep(int nSecond) f7J,&<<5w  
{ iITp**l  
try{ C0fmmI0z~  
Thread.sleep(nSecond); YsP/p-  
} !8*McOI  
catch(Exception e) 'L{p,  
{ gDCOLDM  
e.printStackTrace (); ]TSg!H  
} m_*R.a  
} .#fPw_i  
:[sOKV i  
//日志 K;U39ofW  
public static void log(String sMsg) kX[fy7rVt  
{ We}lx{E  
System.err.println(sMsg); Z^zbWFO
]5  
} m&IsDAn  
%M&3VQ9w  
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public static void log(int sMsg) kq-6HDR  
{ e"Rm_t  
System.err.println(sMsg); 5)'P'kVi7.  
} o2=A0ogz?  
} K=6UK%y A  
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/* +y&d;0!  
**TestMethod.java dB;3.<S=  
*/ "&lN\&:  
package NetFox; Z0ReWrl;`  
~ y;y(4<  
jxw_*^w"  
public class TestMethod { t`G)b&3_O  
:eOR-}p'  
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public TestMethod() M3pjXc<O  
{ ///xx/weblogic60b2_win.exe f vLC_'M  
try{ 4_LQ?U>$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }Qrab#v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WM,i:P)b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4/*H.Fl  
fileFetch.start(); ~p*1:ij  
} Pxhz@":[  
catch(Exception e){e.printStackTrace ();} |d7$*7TvV  
}+RB=#~o  
6)e5zKW!?  
} ?znSx}t  
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public static void main(String[] args) ^0tw%6:  
{ @Bs0Avj.  
new TestMethod(); 4h|dHXYZ  
} otr>3a*'  
} B@t'U=@7  
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