http断点续传简单实现（java)

/* E/_n}$Z  
**SiteFileFetch.java GZ.KL!,R!  
*/ cp
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package NetFox; U \jFB*U  
import java.io.*; 0VIR=Pbp  
import java.net.*; vSk1/  
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public class SiteFileFetch extends Thread { ;>Z0e`=  
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SiteInfoBean siteInfoBean = null; //文件信息Bean th+LScOX  
long[] nStartPos; //开始位置 ~2QD.(  
long[] nEndPos; //结束位置 hjp,v)#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 TZarI-A  
long nFileLength; //文件长度 + ,rl\|J%  
boolean bFirst = true; //是否第一次取文件 'fY29Xr^  
boolean bStop = false; //停止标志 H WFnIUv  
File tmpFile; //文件下载的临时信息 YyC$\HH6  
DataOutputStream output; //输出到文件的输出流 >FL%H=]  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） *++}ll6  
public SiteFileFetch(SiteInfoBean bean) throws IOException svMu85z  
{ 'Kd-A:K2g  
siteInfoBean = bean; dRBWJ/ 1T  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); e)|5P  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  mEbj  
if(tmpFile.exists ()) 'NDr$Qc3  
{ 9\%`/tJM  
bFirst = false; EHrr}&  
read_nPos(); KqXPxp^_Al  
} Lo}zT-F  
else iL'j9_w,  
{ ;6*$!^*w  
nStartPos = new long[bean.getNSplitter()]; ne=C
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nEndPos = new long[bean.getNSplitter()]; Bu4@FIK!C  
} j_SUR)5  
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} _Pn 1n  
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public void run() &cy<"y  
{ Dc0CQGx9b  
//获得文件长度 eU\_m5xl"  
//分割文件 &PFK0tY  
//实例FileSplitterFetch TmJXkR.5  
//启动FileSplitterFetch线程 fj[Kbo 7!h  
//等待子线程返回 M} Mgz  
try{ Zl?9ibm;@  
if(bFirst) {
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{ 3lN@1jlh  
nFileLength = getFileSize(); l_P90zm39!  
if(nFileLength == -1) U"L-1]L  
{ BxB B](  
System.err.println("File Length is not known!"); zEw~t&:e  
} Sp[]vm8N  
else if(nFileLength == -2) Cw~fP[5XMF  
{ t_\&LMD  
System.err.println("File is not access!"); H"wIa8A  
}  Rp6q)  
else =|H.r9-PK6  
{ }w{E<C(M  
for(int i=0;i<nStartPos.length;i++) x}#N?d
  
{ 2g;Id.i>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); i>(TPj|  
} G}@a]EGm  
for(int i=0;i<nEndPos.length-1;i++) )g`~,3G  
{ t<e3EW@>>  
nEndPos = nStartPos[i+1]; &@'+h* b  
} @GF3g=  
nEndPos[nEndPos.length-1] = nFileLength; a?*pO`<J{  
} *C.Kdf3w  
} >C`#4e?}  
Fm+V_.H/;  
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//启动子线程 }l_8~/9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5i%\m  
for(int i=0;i<nStartPos.length;i++) .d+zF,02Z  
{ xxOhGA)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V9wL3*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %{0F.  
nStartPos,nEndPos,i); Us% _'}(/U  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?h,.1Tb  
fileSplitterFetch.start(); KIY9?B=+  
} o 9d|XY_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~iq=J5IN#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); DkW^gt  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \+k~p:d_8  
nEndPos = " + nFileLength); vILgM\or  
// fileSplitterFetch[nPos.length-1].start(); =)J<R;  
l/A!ofc#)  
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//等待子线程结束 qf{HGn_9~1  
//int count = 0; mv(/M t  
//是否结束while循环 ^grDP*;W  
boolean breakWhile = false; UkC'`NWF*  
#p-\Y7f  
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while(!bStop) ?
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{ .p(r|5(b  
write_nPos(); WZ UeW*#=  
Utility.sleep(500); LVdtI  
breakWhile = true; QRwOv  
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3V<c4'O\W  
for(int i=0;i<nStartPos.length;i++) 2m9qg-W  
{ VOT9cP^6  
if(!fileSplitterFetch.bDownOver) /buj(/q^#  
{ nPH\Lra  
breakWhile = false; $9Gra#  
break; <eZrb6a'  
} )M@^Z(W/a  
} SBY0L.  
if(breakWhile) ^!x qOp!  
break; n%!50E6*:  
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zbfe=J4c  
//count++; m3XT8F*&  
//if(count>4) (Z8wMy&:  
// siteStop(); ed#>q;jX  
} S(0JBGC  
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System.err.println("文件下载结束！"); .GWN~iR(  
} Hio+k^  
catch(Exception e){e.printStackTrace ();} M{p9b E[j  
} AG"iS<u  
pqe%tRH{  
FA;B:O@:'  
//获得文件长度 JvS ~.g1  
public long getFileSize() KVoM\ttP  
{ AOx8OiqE:  
int nFileLength = -1; 'Y]<1M>.g  
try{ n,{  
URL url = new URL(siteInfoBean.getSSiteURL()); ${`q
!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &?k`rF9  
httpConnection.setRequestProperty("User-Agent","NetFox"); JC}T*h>Ee  
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int responseCode=httpConnection.getResponseCode(); 0UQ DB5u  
if(responseCode>=400) A@reIt  
{ ,? Q1JZPy@  
processErrorCode(responseCode); id]}10  
return -2; //-2 represent access is error 5xa!L@)`wF  
} :^]FpUY  
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String sHeader; B9'2$s+Z;  
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for(int i=1;;i++) 9xL`i-7]  
{ y/+y |.Xg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +:u &]  
//Utility.log(in.readLine()); ?l`|j*  
sHeader=httpConnection.getHeaderFieldKey(i); uC2 5pH"  
if(sHeader!=null) +\J+?jOC4S  
{
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if(sHeader.equals("Content-Length")) CC]q\%y-_  
{ w# ;t$qz}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N]G`]  
break; XOEf,"  
} c32"$g  
} d/E0opv  
else )F6p+i="  
break; C6d#+  
} ZV[-$  
} &CfzhIi*!  
catch(IOException e){e.printStackTrace ();} "rw'mogRL  
catch(Exception e){e.printStackTrace ();} 7QaZ|\c  
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Utility.log(nFileLength); p(A[ah_  
' &Nv|v\V  
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return nFileLength; 5=;'LW
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} 2F:X:f  
z{qn|#}  
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//保存下载信息（文件指针位置） 'A/f>W  
private void write_nPos() T"E%;'(cp)  
{ 3.%jet1  
try{ ^1XnnQa  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?#L5V'ZZ*  
output.writeInt(nStartPos.length); 5%"0  
for(int i=0;i<nStartPos.length;i++) fjS#  
{ S|_lbMZM  
// output.writeLong(nPos); ZMch2 U8  
output.writeLong(fileSplitterFetch.nStartPos); |tO.@+[uqP  
output.writeLong(fileSplitterFetch.nEndPos); lV?OYS|4i  
}  "-G&]YMl  
output.close(); Tg v]30F)  
} > !WFY  
catch(IOException e){e.printStackTrace ();} 3 FLht L  
catch(Exception e){e.printStackTrace ();}  j g_;pn  
} $"Nqto~  
f
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//读取保存的下载信息（文件指针位置） $HV`bJ5!L*  
private void read_nPos() 9>d~g
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{ kk aS&r>  
try{ lI+KT_|L  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y IVN;:B.  
int nCount = input.readInt(); _u;34H&/  
nStartPos = new long[nCount]; , ins/-3  
nEndPos = new long[nCount]; h8HA^><Xr  
for(int i=0;i<nStartPos.length;i++) Xyw;Nh!!d  
{ MG$Df$R  
nStartPos = input.readLong(); !(qaudX{>k  
nEndPos = input.readLong(); h>n<5{zqM  
} k7bfgb{  
input.close(); 3yM!BTlX  
} "C]_pWk  
catch(IOException e){e.printStackTrace ();} S&~;l/  
catch(Exception e){e.printStackTrace ();} q7zHT=@$  
} 7XiR)jYo*  
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private void processErrorCode(int nErrorCode) -}Gk@=$G  
{ 9icy&'  
System.err.println("Error Code : " + nErrorCode); :4S~}
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} 5~xv"S(E}  
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aP +)  
//停止文件下载 Ga$EM  
public void siteStop() @ {8xL  
{ *iujJi  
bStop = true; ]q@W(
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for(int i=0;i<nStartPos.length;i++) MJ`BlE,Fmb  
fileSplitterFetch.splitterStop(); 1.q a//'RW  
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@4j!M1}4  
} ziD+% -  
} k0-,qM#p;X  
//负责部分文件的抓取 )cxML<j'  
**FileSplitterFetch.java _6MNEoy?  
*/ _<;westq  
package NetFox; {@3p^b*E)1  
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> 0NDlS%Q:  
import java.io.*; 98t|G5  
import java.net.*; PH]ui=  
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public class FileSplitterFetch extends Thread { JJE0q5[  
-'::$ {  
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String sURL; //File URL ~(d#T|ez  
long nStartPos; //File Snippet Start Position >[TJ-%V>oR  
long nEndPos; //File Snippet End Position 6R%NjEW:  
int nThreadID; //Thread's ID kG]FB.@bG  
boolean bDownOver = false; //Downing is over o`ijdg!5qG  
boolean bStop = false; //Stop identical ? Eh)JJt  
FileAccessI fileAccessI = null; //File Access interface /N\[ C"8  
uHpSE?y/  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ='GY:.N  
{ @`#"6y?  
this.sURL = sURL; >,QW74o  
this.nStartPos = nStart; `1)n2<B  
this.nEndPos = nEnd; 7%Ii:5Bp  
nThreadID = id; s4Y7x.-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BJ7m3[lz  
} 'Lv>!s 7  
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public void run() p+d?k"WN?  
{ k6W [//  
while(nStartPos < nEndPos && !bStop) pbb6?R,  
{ F5;
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try{ V/i7Zh#2:  
URL url = new URL(sURL); Xw[|$#QKM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LzJNQd'  
httpConnection.setRequestProperty("User-Agent","NetFox"); G[!Y6c3  
String sProperty = "bytes="+nStartPos+"-"; MnymV;y"  
httpConnection.setRequestProperty("RANGE",sProperty); Y'%k
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Utility.log(sProperty); ?g #4&z.  
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{`CmE/`{  
InputStream input = httpConnection.getInputStream(); E0Jk=cq  
//logResponseHead(httpConnection); [P?.(*  
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byte[] b = new byte[1024]; 4m
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int nRead; p(]o#$ 6[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )r
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{ ;NeN2|I]  
nStartPos += fileAccessI.write(b,0,nRead); q2KWSh
5  
//if(nThreadID == 1) $mp'/]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pUXszPf  
} b(.,Ex]  
vx8-~Oq{|;  
.ITR3]$  
Utility.log("Thread " + nThreadID + " is over!"); v22ZwP  
bDownOver = true; p[lciWEW  
//nPos = fileAccessI.write (b,0,nRead); V57tn6>b  
} 0"to]=  
catch(Exception e){e.printStackTrace ();} nI6[y)j  
} *ioVLt,:R  
} R-2V C  
> : ;*3  
SH${\BKup  
//打印回应的头信息 v&i,}p^M5  
public void logResponseHead(HttpURLConnection con) T1Y_Jf*KJ  
{ l&1R`gcW  
for(int i=1;;i++) nofK(0TF  
{ 51lN,VVD  
String header=con.getHeaderFieldKey(i); P1f@?R&t+  
if(header!=null) H%AC *,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >k{KwFB^S  
Utility.log(header+" : "+con.getHeaderField(header)); j? P=}_Ru  
else (77EZ07%  
break; ($ l t@j  
} >m;*Zk`  
} '-[~I>o%  
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public void splitterStop() zU$S#4/C  
{ hB)TH'R{:  
bStop = true; M} {'kK  
} 8bIwRVA2\  
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} 8 k%!1dyMB  
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/* 1SYBq,[])  
**FileAccess.java 9L^:N)-  
*//文件访问(定位，写) +Y  
package NetFox; )mVpJYt;  
import java.io.*; a9CK4Kg  
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pNzSy"Y$  
public class FileAccessI implements Serializable{ oTqv$IzqP  
ADQ#qA,/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Q7-d]xJ^  
RandomAccessFile oSavedFile; x.OCE`  
long nPos; t$W~X~//  
&:"[hU  
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public FileAccessI() throws IOException $ }D9)&f;  
{ yxt`  
this("",0); ]7ZY|fP2  
} c<gvUVHIxR  
_PR><L_  
C3p/|{TP  
public FileAccessI(String sName,long nPos) throws IOException LT ZoO9O  
{ *j0kb"#  
oSavedFile = new RandomAccessFile(sName,"rw"); ,`ZIW  
this.nPos = nPos; tb@&!a$`?  
oSavedFile.seek(nPos); *Bgk3(n)  
} .^%!X!r  
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CQ+WBTiC  
public synchronized int write(byte[] b,int nStart,int nLen) ZV;lr Vv  
{ s28rj6q  
int n = -1; n 7Bua  
try{ 2}^fhMS  
oSavedFile.write(b,nStart,nLen); yA/
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n = nLen; ,,-g*[/3  
} X-&U-S;  
catch(IOException e) *mgK^9<  
{ |rDv!m  
e.printStackTrace (); #~SQujgB  
} pg%'_+$~m  
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return n; DgQw9`WA  
} ARD&L$AX  
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} &Jr~)o   
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)OAd[u<  
/* M@n9i@UsO  
**SiteInfoBean.java AJ*FQo.U  
*/ AIR\>.~"i*  
package NetFox; Q'ok%9q!p  
(\QkXrK  
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public class SiteInfoBean { W\tSXM-Hg  
$1h,<$5H  
b@yGa%Gz@  
private String sSiteURL; //Site's URL T@ [
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private String sFilePath; //Saved File's Path cG"+n@\  
private String sFileName; //Saved File's Name H ',Nt  
private int nSplitter; //Count of Splited Downloading File Fj`6v"h  
(>E70|T  
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public SiteInfoBean() Zljj  
{//nSplitter的缺省值为5 `nxm<~-\  
//default value of nSplitter is 5 kAEm#oz=g  
this("","","",5); =3Y:DPMB  
} 4EO,9#0  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _dT,%q  
{ W+&w'~M  
sSiteURL= sURL; 3}@!TI  
sFilePath = sPath; 5,0fL  
sFileName = sName;  vj+x
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this.nSplitter = nSpiltter; z4snH%q  
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b`@aiXN)+  
} wX_s./#JJ  
iY /N%T;  
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public String getSSiteURL() &gn^i!%Z)  
{ Wgt[ACioN  
return sSiteURL; F9sVMV
 
} '\$2+*  
cMCGaaLU  
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public void setSSiteURL(String value) ohHKZZ  
{ 3
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sSiteURL = value; zqaz1rt
[  
} Q1f
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public String getSFilePath() 1N#KVvK  
{ 8\+Q*7~@i  
return sFilePath; Jon<?DQj  
} e5!LbsJv  
H]LH~l  
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public void setSFilePath(String value) >Cb[  
{ =tJ}itcJ'  
sFilePath = value; Pd99vq/  
} [MmOPm}@  
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public String getSFileName() RJ ,a}w[9  
{ jt?937{  
return sFileName; pXfg{2  
} =K6aiP$Ft  
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public void setSFileName(String value) ]-Z="YPY  
{ _;] 3w  
sFileName = value; X~DI d  
} H\OV7=8  
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Iv6(Z>pAB  
public int getNSplitter() os<B}D[  
{ qSRE)C=)  
return nSplitter; (x{
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} RR u1/nam  
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/bE=]nM  
public void setNSplitter(int nCount) }H!l@  
{ T}ZUw;}BL  
nSplitter = nCount; b~khb!]  
} 1}A1P&2>  
} TA=VfA B  
;VY0DAp{  
n%o"n?e  
/* xef@-%mcoy  
**Utility.java 50:gk*hy  
*/ ;aJBx  
package NetFox; S&y(A0M  
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public class Utility { E2M|b  
@Sxb}XI!f  
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public Utility() 8+ P)V4}  
{ >z'kCv
  
_e%jM[  
Ccmo(W+0  
} (^fiw%#  
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//线程睡眠 6Z:<?_p%7g  
public static void sleep(int nSecond) y\]~S2}G  
{ "0JG96&\  
try{ %F'*0<  
Thread.sleep(nSecond); 7^}np^[HB  
} Y`5(F>/RQG  
catch(Exception e) | |=q"h3(  
{ &tT*GjPwg;  
e.printStackTrace (); W'l &rm@  
}  `Pa)H  
} cNi)[2o7  
M_wqb'=  
//日志 {H FF|Dx  
public static void log(String sMsg) '+6H=Qn  
{ Z5lE*z  
System.err.println(sMsg); _^+z2m+~N  
} %SW"{GnO^  
V87?J w%2  
p<5ED\;N;  
public static void log(int sMsg) XG]ltSOy  
{ S2/6VoGE  
System.err.println(sMsg); \ /(;LHWQ  
}
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} A=LyN$%  
%A@Q%l6  
XH_XGzBQS  
/* 5$kv,%ah  
**TestMethod.java 1'qllkT  
*/ 2b|$z"97jj  
package NetFox; %d..L-`]ET  
>'>onAIL  
8cqH0{  
public class TestMethod { 3l?D%E]P  
7Sc._G{[%  
6\MH2&L<  
public TestMethod() a!Z.Z
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{ ///xx/weblogic60b2_win.exe 5,3Yt~\m  
try{ Ij+ E/V  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 739J] M  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); E;[ANy4L  
SiteFileFetch fileFetch = new SiteFileFetch(bean); V2< 4~J2:9  
fileFetch.start(); %1E:rw@
 
} 0/".2(\}T  
catch(Exception e){e.printStackTrace ();} %nU8 Ca  
o)_;cCr)q  
h,:8TMJRRN  
} nwH'E  
]#n,DU}V  
nJ!`^X5I  
public static void main(String[] args) qA4w*{JN  
{ yDwG,)m 4s  
new TestMethod(); ;t'~  
} &X0qH8W  
} }O+F#/6  
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