http断点续传简单实现（java)

/* 3gd&i  
**SiteFileFetch.java jReXyRmo({  
*/ zg-2C>(6a  
package NetFox; !uQPc  
import java.io.*; orOt>5}b<  
import java.net.*;
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public class SiteFileFetch extends Thread { o,|[GhtHqs  
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SiteInfoBean siteInfoBean = null; //文件信息Bean V5*OA??k<  
long[] nStartPos; //开始位置 \=_{na_  
long[] nEndPos; //结束位置 Y ')x/H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 0}_[DAd6  
long nFileLength; //文件长度 giz7{Ai  
boolean bFirst = true; //是否第一次取文件 gz3pX#S  
boolean bStop = false; //停止标志 {nLjY|*  
File tmpFile; //文件下载的临时信息 Qxj JN^Q  
DataOutputStream output; //输出到文件的输出流 M(/r%-D  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _a1x\,R|DB  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ja9e^`i;  
{ D9M:^  
siteInfoBean = bean; s6>ZREf#J  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =:~R=/ZXk  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); KEWTBBg  
if(tmpFile.exists ()) >,td(= :  
{ hdrm!aBd  
bFirst = false;
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read_nPos(); W*2U="t  
} |P%Jw,}]9  
else }sxYxn~  
{ thhwN A  
nStartPos = new long[bean.getNSplitter()]; Dc,I
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nEndPos = new long[bean.getNSplitter()]; ~
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} P-9<YN  
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} ?!+MM&c-n  
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public void run() R6(oZph  
{ 9g<7i  
//获得文件长度 =zz~kon9  
//分割文件 #"B\UN  
//实例FileSplitterFetch ^jx7@LgS=  
//启动FileSplitterFetch线程 P?k0zwOlBl  
//等待子线程返回 O&Y*pOg  
try{ pej|!oX  
if(bFirst) 4T ~
}  
{ 62zYRs\Y)X  
nFileLength = getFileSize(); 1u:< 25  
if(nFileLength == -1) =|Y,+/R?  
{ }"|K(hq  
System.err.println("File Length is not known!"); ,'u W*kx  
} h D/*h*}T>  
else if(nFileLength == -2) nR-YrR*k  
{ -X"
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System.err.println("File is not access!"); cH&J{WeZa  
} -[wGX}}  
else aJ>65RJ^=  
{ lz?$f4TzA  
for(int i=0;i<nStartPos.length;i++) \RG8{G,  
{ bJX)$G  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J|qZ+A[z
 
} ax<?GjpM  
for(int i=0;i<nEndPos.length-1;i++) LA}Syt\F  
{ 9@Jtaq>jf  
nEndPos = nStartPos[i+1]; Hhcpp7cr'  
} BW$"`T@c6~  
nEndPos[nEndPos.length-1] = nFileLength; (^Y~/  
} i uF*.hc,%  
} IhVO@KJI  
v
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//启动子线程 QD0"rxZJ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?M\{&mlF  
for(int i=0;i<nStartPos.length;i++) *=V~YF:Qb  
{ # mV{#B=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *Qg_F6y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >LOjV0K/  
nStartPos,nEndPos,i); _I:/ZF5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A\HxDIU  
fileSplitterFetch.start(); `ojoOB^L  
} u=`L
)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \nPEyw,U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~Vr.J}]J  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )p<ExMIxd  
nEndPos = " + nFileLength); ~?K~L~f5  
// fileSplitterFetch[nPos.length-1].start(); o!kbK#k  
ur:3W6ZKl  
5\]Sv]s)R  
//等待子线程结束 xdp`<POn%  
//int count = 0; R#%(5-Zu#R  
//是否结束while循环 wA
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boolean breakWhile = false; qVH1}9_  
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while(!bStop) [OC5l>  
{ E2R&[Q"%  
write_nPos(); 6ZP(E^.  
Utility.sleep(500); LG9+y  
breakWhile = true; l1BtI_7p  
{>hC~L?
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for(int i=0;i<nStartPos.length;i++) fSK]|"c  
{ ,(EO'T[  
if(!fileSplitterFetch.bDownOver) Rh_
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{ #
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breakWhile = false; t*Sa@$p  
break; I ?gSG*m  
} (nf~x  
} Z2qW\E^_r  
if(breakWhile) /5(Yy}  
break; Azl&mu  
n"G&ENN"$  
}`%*W`9b  
//count++; RtTJ5@V(  
//if(count>4) |$8~?7Jv  
// siteStop(); c;Pe/d  
} 7z JRJ*NB  
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System.err.println("文件下载结束！"); ,,%i;  
} gQ Fjr_IS#  
catch(Exception e){e.printStackTrace ();} D$ dfNiCH  
} Xg|B \\  
J:CXW%\ <q  
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//获得文件长度 I>]oS(GNT  
public long getFileSize() lr>oYS0  
{ 5m\<U`  
int nFileLength = -1;
8']M^|1  
try{ e7Xeo+/  
URL url = new URL(siteInfoBean.getSSiteURL()); 6#7Lm) g8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m$}R%  
httpConnection.setRequestProperty("User-Agent","NetFox"); KL1/^1  
\^L`7cBL  

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int responseCode=httpConnection.getResponseCode(); ]zE;Tw.S  
if(responseCode>=400)
[^Os kJ4  
{ *W,]>v0%T  
processErrorCode(responseCode); .}t~'*D  
return -2; //-2 represent access is error ]O+Ma}dxz:  
} uki#/GzaO  
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String sHeader; =RA /  
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for(int i=1;;i++) y"bByd|6  
{ 0m%|U'm|j  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); g
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//Utility.log(in.readLine()); q)X$^oE!6  
sHeader=httpConnection.getHeaderFieldKey(i); <"{qk2LS1  
if(sHeader!=null) Uzz'.K(Mv|  
{ @$S+Ne[<  
if(sHeader.equals("Content-Length")) S%bCyK%p  
{ & ?h#Z!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); XewVcRo  
break; g7}Gip}.>  
} t3
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} .k,1f*%  
else RDW8]=uM  
break; ciBP7>'::  
} h`KFL/fT  
} hn5h\M?  
catch(IOException e){e.printStackTrace ();} G`SUxhCk  
catch(Exception e){e.printStackTrace ();} K0-ypU*P  
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5]KW^sL  
Utility.log(nFileLength); %<k2#6K  
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return nFileLength; d4u})  
} t2/#&J]  
lD)%s!  
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//保存下载信息（文件指针位置） zL$@`Eh-KP  
private void write_nPos() *w^C"^*  
{ f[<m<I  
try{ B:5Rr}eY+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )WRLBFi
3  
output.writeInt(nStartPos.length); *W.C7=  
for(int i=0;i<nStartPos.length;i++) <;vbsksZeH  
{ f,h
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// output.writeLong(nPos); h].<t&  
output.writeLong(fileSplitterFetch.nStartPos); $Z.7zH  
output.writeLong(fileSplitterFetch.nEndPos); @Z*W  
} Dd'm U  
output.close(); pWy=W&0~qf  
} YLqGRE`W  
catch(IOException e){e.printStackTrace ();} $bW3_rl%X  
catch(Exception e){e.printStackTrace ();} f\]sz?KY  
} _,p/l&<  
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//读取保存的下载信息（文件指针位置） o)Iff)m$  
private void read_nPos() SX<` {x&L  
{ Rn}l6kbM  
try{ gp5_Z-me  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wN@oYFoL  
int nCount = input.readInt(); 2/vMoVT,  
nStartPos = new long[nCount]; -=%@L&y1  
nEndPos = new long[nCount]; =d".|k  
for(int i=0;i<nStartPos.length;i++) ;XF:\<+  
{ >"|B9Woc  
nStartPos = input.readLong(); I;e=0!9U  
nEndPos = input.readLong(); \n$u)Xj~6^  
} h]Wr [v  
input.close(); 4lr(,nPRD  
} I KqQ>Z-q~  
catch(IOException e){e.printStackTrace ();} H\h3TdL  
catch(Exception e){e.printStackTrace ();} $w)!3c4  
} 1;C+$  
=Q+;=-1  
@Ws*QTlV  
private void processErrorCode(int nErrorCode) n,jKmA  
{ hlV=qfc  
System.err.println("Error Code : " + nErrorCode); Z'4./  
} Wi*.TWz
3  
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//停止文件下载 g l^<Q  
public void siteStop() gW^VVbB'L  
{ Yk)."r
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bStop = true; w$+&3t  
for(int i=0;i<nStartPos.length;i++) a6D &/8  
fileSplitterFetch.splitterStop(); 5~r33L%  
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} }T; P~aG  
} Tu
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//负责部分文件的抓取 5>CEl2mSl  
**FileSplitterFetch.java zDw5]*R  
*/ 24E}<N,g  
package NetFox; rm5bkJcg~  
~ DBcIy?  
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import java.io.*; ZjgsR|i  
import java.net.*; s"0Y3x3  
!F1M(zFD  
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public class FileSplitterFetch extends Thread { 9{(.Il J>  

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String sURL; //File URL z2MWN\?8  
long nStartPos; //File Snippet Start Position :# .<[  
long nEndPos; //File Snippet End Position u])b,9&En  
int nThreadID; //Thread's ID W~zbm]  
boolean bDownOver = false; //Downing is over RZHd9v$  
boolean bStop = false; //Stop identical 2[Z,J%:0  
FileAccessI fileAccessI = null; //File Access interface N!ls j \-  
'JCZ]pZ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException uEktQ_u[  
{ +@94;me  
this.sURL = sURL; U@HK+C"M|  
this.nStartPos = nStart; G`n_YH084  
this.nEndPos = nEnd; n2]/v{E;/  
nThreadID = id; hM;lp1l  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <QA6/Ef7  
} Jl5c [F  
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ox(j^x]NC  
public void run() jE}33"  
{ &^#VN%{  
while(nStartPos < nEndPos && !bStop) C1jHz  
{ /DK"QV!]s  
q
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try{ z`!XhU  
URL url = new URL(sURL); %K>,xiD)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }])oM|fgO  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,{BaePMp  
String sProperty = "bytes="+nStartPos+"-"; s!?`T1L
  
httpConnection.setRequestProperty("RANGE",sProperty); lBK}VU^  
Utility.log(sProperty); ~rDZ?~%  
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InputStream input = httpConnection.getInputStream(); Bk*F_>X"  
//logResponseHead(httpConnection); 3on7~*  
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f|B=_p80  
byte[] b = new byte[1024]; JBXrFC;  
int nRead; tKuVQH~D  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) z.kvX+7'  
{ (BTVD,G  
nStartPos += fileAccessI.write(b,0,nRead); Y&S24aql  
//if(nThreadID == 1) #:[t^}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qv]}$WU  
} vgsJeV`}I  
' 0J1vG~c  
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Utility.log("Thread " + nThreadID + " is over!"); >Db;yC&  
bDownOver = true; Ov-icDMm  
//nPos = fileAccessI.write (b,0,nRead); $6mX  
} cki81bOT  
catch(Exception e){e.printStackTrace ();} >4#)r8;dx  
} te3}d'9&|  
} y9x w 9l'  
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hp#W9@NR  
//打印回应的头信息 %k;|\%B`  
public void logResponseHead(HttpURLConnection con) (Tn- >).AO  
{ do*EKo  
for(int i=1;;i++) wN;^[F  
{ .}OR  
String header=con.getHeaderFieldKey(i); M}yDXJx  
if(header!=null) r[4tPk  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =p*]Az  
Utility.log(header+" : "+con.getHeaderField(header)); AS =?@2 q  
else ^>jwh  
break; &3bx`C  
} .?R!DYC`  
} 9aze>nxh.  
jz qyk^X  
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public void splitterStop() y+"X~7EX  
{ 4)A#2  
bStop = true; ,Wk?I%>  
} ]j`c]
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SKkUU^\#R`  
} j`~Ms>  
kQEy#JQmB  
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/* BW 4%l  
**FileAccess.java a-=8xs'
 
*//文件访问(定位，写) ^pQCNKLBY  
package NetFox; y#U+c*LB  
import java.io.*; D;;!ODX$?  
gBC@38|6)  
2/"u
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public class FileAccessI implements Serializable{ :
I+Gu*0WD  
xa<UM5eI  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 n)^i/ nXb'  
RandomAccessFile oSavedFile; [8T^@YN  
long nPos; XCU7xi$d  
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public FileAccessI() throws IOException G#d{,3Gq1  
{ Urr@a/7  
this("",0); ]sE?e
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} "nw;NIp!  
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6YGubH7%_  
public FileAccessI(String sName,long nPos) throws IOException 6]W=nAD  
{ BYVY)<v/  
oSavedFile = new RandomAccessFile(sName,"rw"); q,93nhs "  
this.nPos = nPos; *X+79vG:  
oSavedFile.seek(nPos); Rm255zp  
} -uMSe~  
L.S;J[a;  
" @v <Bk  
public synchronized int write(byte[] b,int nStart,int nLen) p<,*3huj  
{ M$/|)U'W  
int n = -1; 1*9U1\z  
try{ }]lr>"~y}  
oSavedFile.write(b,nStart,nLen); L"o>wYx
 
n = nLen; kXi6lh  
} Z -W(l<  
catch(IOException e) =;2%a(  
{ {L/tst#C  
e.printStackTrace (); Y@N,qHtz  
} SqEgn}m$  
-jb0o/:  
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return n; Wu[&Wv~  
} { g/0x,-Z  
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} _'{_gei_P  
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/* 95A1:A^t  
**SiteInfoBean.java 2jR r,Nl  
*/ /OLFcxEWh  
package NetFox; cx&>#8s&  
}o(zj=7  
Ye2 {f"F  
public class SiteInfoBean { _AAaC_q  
!g5
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bpH^:fyLU`  
private String sSiteURL; //Site's URL 62k^KO6Y  
private String sFilePath; //Saved File's Path x4;"!Kq\  
private String sFileName; //Saved File's Name ?[g=F <r  
private int nSplitter; //Count of Splited Downloading File "Zl5<  
fI{&#~f4C  
[5G6VNh=  
public SiteInfoBean() IsZHelg  
{//nSplitter的缺省值为5 .1KhBgy^K  
//default value of nSplitter is 5 d1AioQ9  
this("","","",5); iOU6V  
} mz,  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ="Ho%*@6  
{ *AO,
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sSiteURL= sURL; 'EbWFMjy  
sFilePath = sPath; 3RYpJAH  
sFileName = sName; u%}nw :>  
this.nSplitter = nSpiltter; e1%/26\  
5*lT.  
>O*IQ[r-  
} CE#gfP  
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*=]&&<  
public String getSSiteURL() ^(vs.U^U<  
{ 95 ;x=ju  
return sSiteURL; B@&4i?yJ  
} CG0 M  
!W5 (  
nuk*.Su  
public void setSSiteURL(String value) =Xi07_8Ic<  
{ v|uAzM{73  
sSiteURL = value; ABQ('#78  
} ';3{T:I  
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public String getSFilePath() s
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{ 1_9<3,7  
return sFilePath; j(m.$:  
} 9^oKtkoDZ  
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public void setSFilePath(String value) l`oZ)?ur  
{ )bS yB29S  
sFilePath = value; llcb~  
} ?[@J8  
f .Q\Z'S^  
AL9chYP}/  
public String getSFileName() n^Hm;BiE#  
{ NQBpX  
return sFileName; s}w{:Hk,x8  
} h2Ld[xvCu%  
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oI }VV6vO  
public void setSFileName(String value) ?}wk.gt>  
{ #M9~L[nFS  
sFileName = value; G<}()+L  
} ?zh9d%R  
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public int getNSplitter() #.rdQ,)<  
{ b*a#<K$T_  
return nSplitter; 7m4ao
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}

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);#JL0I  
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public void setNSplitter(int nCount) ]{3)^axW;  
{ l4F%VR4KT  
nSplitter = nCount; 2BQ j  
} Cn,d?
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} g;pcZ9o
 
s'!Cp=xQF"  
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/* S0zD"T  
**Utility.java ^uKwB;@  
*/
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package NetFox; 3@kf@Vf  
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public class Utility { uxXBEq;  
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public Utility() )(bW#-  
{ h;
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} 94h]~GqNi  
fz|
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//线程睡眠 IHB}`e|  
public static void sleep(int nSecond) XW[j!`nlk  
{ `F-/QX[:  
try{ Oxm>c[R  
Thread.sleep(nSecond); J[l7di5  
} qX/y5F`  
catch(Exception e) v[ .cd*b  
{ ]OM"ZG/^  
e.printStackTrace (); c/D+|X*  
} ?4+9fE<Q  
} L{X_^  
^]H5h]U'  
//日志 k Z?=AXu  
public static void log(String sMsg) F^WP<0C  
{ B^1>PE  
System.err.println(sMsg); Vx$\hcG  
} !\-{D$E?H  
+9M^7/}H  
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public static void log(int sMsg) C6VLy x  
{ 6c}h(TkB  
System.err.println(sMsg); @@R7p  
} ,BH@j%Jmy  
} *1uKr9  
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Z?6%;n^ 54  
/* @3) (BpFe  
**TestMethod.java qyZ" %Kz  
*/ =b%MXT  
package NetFox; 1a?!@g)  
O9G[j=U  
qU+t/C.  
public class TestMethod { VrHv)lUr  
m}C>ti`VD  
ap.K=-H  
public TestMethod() rA3$3GLQ-  
{ ///xx/weblogic60b2_win.exe Jb0`42
 
try{ tRs [ YK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); p)jk>j B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); rV2WnAb[H&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -z-C*%~  
fileFetch.start(); *F+KqZ.2  
} g,Lq)'N;O  
catch(Exception e){e.printStackTrace ();} P2NQHX  
^|/TC!v]M  
Tl%`P_J)-S  
} EMh7z7}Rr  
4QH3fTv   
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public static void main(String[] args) ~Y`ldL  
{ ,`|3KE9  
new TestMethod(); y<?kzt  
} LzG%Z1`  
} Z~AO0zUKY  
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