http断点续传简单实现（java)

/* 8`EzvEm  
**SiteFileFetch.java 9fp1*d  
*/ ZZL.&Ho  
package NetFox; G'^Qi}o  
import java.io.*; ^w5`YI4<  
import java.net.*; V:4]]z L}  
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public class SiteFileFetch extends Thread { I dgha9K  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ypM0}pdvTp  
long[] nStartPos; //开始位置 f wWI2"}  
long[] nEndPos; //结束位置 {9q~bt  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ykrb/j|rK  
long nFileLength; //文件长度 %>_ZUu3M  
boolean bFirst = true; //是否第一次取文件 .S>:-j'u  
boolean bStop = false; //停止标志 AifnC4  
File tmpFile; //文件下载的临时信息 I'{-T=R-q  
DataOutputStream output; //输出到文件的输出流 M.O3QKU4  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） f7c%Z:C#Y  
public SiteFileFetch(SiteInfoBean bean) throws IOException cY
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{ paF$o6\  
siteInfoBean = bean; d[;Sn:B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); w[~O@:`]<o  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); J+r\EN^9  
if(tmpFile.exists ()) p^_2]%,QeM  
{ y, @I6  
bFirst = false; 9!6sf GZ  
read_nPos(); ;i\m:8!;  
} "q5Tw+KCfu  
else ~Wp>tnl  
{ ;N6Euiz  
nStartPos = new long[bean.getNSplitter()]; ^ 
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nEndPos = new long[bean.getNSplitter()];  w~wpm7  
} n@<+D`[.V  
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} DUUQz:?{J  
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public void run() bq#*XCt#  
{ r)UtS4 7  
//获得文件长度 _yw]Cacr\  
//分割文件 #q'J`BC  
//实例FileSplitterFetch atRWKsY<  
//启动FileSplitterFetch线程 2{:bv~*I0F  
//等待子线程返回 Hg(%gT  
try{ %;$zR}  
if(bFirst) 8R<2I1xn2  
{ ;L (dmx?  
nFileLength = getFileSize(); MwMv[];I  
if(nFileLength == -1) lcR53X  
{ Q^}6
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System.err.println("File Length is not known!"); 9aky+  
} =oz$uD}?  
else if(nFileLength == -2) tfW*(oU  
{ $Tci_(V=F  
System.err.println("File is not access!"); c `C /U7j  
} >|Ps23J#  
else 7<;87t]]  
{ <RH2G  
for(int i=0;i<nStartPos.length;i++) /qp)n">  
{ <
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); %2>ya>/M  
} YBb%D  
for(int i=0;i<nEndPos.length-1;i++) @k~'b  
{ uf4C+c
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nEndPos = nStartPos[i+1]; ?hu}wl)  
} s @\UZC  
nEndPos[nEndPos.length-1] = nFileLength; xV@/z5Tq  
} R3=PV{`M  
} ?Ho~6q8O@  

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//启动子线程 qXC>DGy  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &}%rZU  
for(int i=0;i<nStartPos.length;i++) iv@ey-,<  
{ OtK=UtVI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >(nb8T|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), S-@E  
nStartPos,nEndPos,i); >Wvb!8N  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7J?`gl&C  
fileSplitterFetch.start(); $KDH"J  
} e lj
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^PHWUb+``  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); rBR,lS$4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6bj.z  
nEndPos = " + nFileLength); AY3nQH   
// fileSplitterFetch[nPos.length-1].start(); :rr;9nMR[  
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V}de|=  
//等待子线程结束 5>{  
//int count = 0; "W!Uxc  
//是否结束while循环 ,.Xqb~  
boolean breakWhile = false; kaybi 0  
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while(!bStop) }?^V9K-  
{ =P>c1T1-  
write_nPos(); cbsU!8
 
Utility.sleep(500); |-kU]NJFR  
breakWhile = true; 3!]S8Y*LQP  
|cKo#nfzZ  
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for(int i=0;i<nStartPos.length;i++) Npu#.)G  
{ [wKnJu  
if(!fileSplitterFetch.bDownOver) kC~\D?8E=  
{ zl~`>  
breakWhile = false; YMGzO  
break; !@2L g  
} g?Jx99c;  
} aH@GhI
^@  
if(breakWhile) :mOHR&2xR%  
break; G .PzpBA  
9em?2'ysa  
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//count++; w=]id'`?q  
//if(count>4) yffg_^fR  
// siteStop(); E"8cB]`|8  
} H<6TN^  
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System.err.println("文件下载结束！"); K7o!,['W  
} f;";P
 
catch(Exception e){e.printStackTrace ();} aB@D-Y"HO  
} {{'GR"D  
Z.:g8Xl-6  
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//获得文件长度 RE*;_DF  
public long getFileSize() df@r2 /Y  
{ 6[cC1a3r:  
int nFileLength = -1; vd0;33$L  
try{ ShFC@)<lJ  
URL url = new URL(siteInfoBean.getSSiteURL()); 7;]n+QRfm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i{1SUx+Re  
httpConnection.setRequestProperty("User-Agent","NetFox"); sw:o3cC]  
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int responseCode=httpConnection.getResponseCode(); fC1PPgQ\  
if(responseCode>=400)  Z1
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{ 0M[O(.x  
processErrorCode(responseCode); POZ5W)F(  
return -2; //-2 represent access is error W ='c+3O6  
} ;S,k U{F  
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String sHeader; g>g]qQ  
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for(int i=1;;i++) Sxn#  
{ 7bC1!x*qw  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?<_yW#x6  
//Utility.log(in.readLine()); 0Fd<@wQ0  
sHeader=httpConnection.getHeaderFieldKey(i); *RPdU.  
if(sHeader!=null) -)='htiU  
{ Io8h 8N-  
if(sHeader.equals("Content-Length")) d#Hl3]wT  
{ dS+/G9X^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =1/d>kke  
break; 6.uyY@Yx  
} nDiy[Y-4Wp  
} ! };OLQ  
else OHEl.p]|  
break; pi/Jto25z  
}
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} ar+ j`QIe  
catch(IOException e){e.printStackTrace ();} 8xAxn+;  
catch(Exception e){e.printStackTrace ();} c,wYXnJ_t  
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Utility.log(nFileLength); |@Cx%aEKU  
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return nFileLength; Nn`l+WA3  
} P1gW+*?  
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UG@9X/l}  
//保存下载信息（文件指针位置） ?vnO@Bb/a  
private void write_nPos() B~\mr{|u  
{ Rw j4  
try{ tWT,U[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); mgODJ  
output.writeInt(nStartPos.length); SVJL|S3k  
for(int i=0;i<nStartPos.length;i++) o8PK,!Pl  
{ T/m4jf2  
// output.writeLong(nPos); :TPT]q d@  
output.writeLong(fileSplitterFetch.nStartPos); j@7%%   
output.writeLong(fileSplitterFetch.nEndPos); q?&Ap*  
} &oU) ,H  
output.close(); t[dOWgHi  
} ;7;=)/-  
catch(IOException e){e.printStackTrace ();} +-s$Htx  
catch(Exception e){e.printStackTrace ();}
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} g?TPRr~$9  
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//读取保存的下载信息（文件指针位置） D@O#P^?  
private void read_nPos() (pDu  
{ pm)kocG  
try{ Wqy\yS [  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =sp5.-r  
int nCount = input.readInt(); =hw&2c  
nStartPos = new long[nCount]; _m?TEqB  
nEndPos = new long[nCount]; `f|Gw5R  
for(int i=0;i<nStartPos.length;i++) j=q*b Qr  
{ l0 Eh?  
nStartPos = input.readLong(); \sSt _|+  
nEndPos = input.readLong(); -@I+IKz  
} ApT
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input.close(); h?8I`Z)h  
} 4Go$OQ`  
catch(IOException e){e.printStackTrace ();} Ml"i^LR+  
catch(Exception e){e.printStackTrace ();} z_;:6*l=:  
} `rWT^E@p5m  
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private void processErrorCode(int nErrorCode) t9U-
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{ M/d6I$~7z  
System.err.println("Error Code : " + nErrorCode); ?o>JX.Nl&7  
} l?f%2:}m  

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//停止文件下载 6d# 7  
public void siteStop() 2#i*'.  
{ j\LJ{?;jC  
bStop = true; B(eC|:w[z  
for(int i=0;i<nStartPos.length;i++) \dx$G?R
 
fileSplitterFetch.splitterStop(); jmE\+yz  
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} _nn\O3TB  
} 0%W0vTvL  
//负责部分文件的抓取 'joc8o sS  
**FileSplitterFetch.java *XCgl*% *  
*/
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package NetFox; ;ndwVZ~,  
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import java.io.*; j%q,]HCANh  
import java.net.*; ?=},%^  
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public class FileSplitterFetch extends Thread { r@30y/C  
a,/wqX  
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String sURL; //File URL M^6!{c=MIi  
long nStartPos; //File Snippet Start Position C/JFb zVx  
long nEndPos; //File Snippet End Position ^e~m`R2fHh  
int nThreadID; //Thread's ID F7"v}K]X  
boolean bDownOver = false; //Downing is over 9kO}054  
boolean bStop = false; //Stop identical vl"{ovoC  
FileAccessI fileAccessI = null; //File Access interface 9w:F_gr  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s?9$o Qq1  
{ \* /R6svz  
this.sURL = sURL; E*W|>2nx]  
this.nStartPos = nStart; JYe
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this.nEndPos = nEnd; (Qp53g  
nThreadID = id; (c\i.z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &OXWD]5$6  
} G@(ukt`0}  
!A|ayYBb\  
 %&81xAt  
public void run() FSNzBN  
{ >hFg,5 _l3  
while(nStartPos < nEndPos && !bStop) tsWzM9Yf  
{ 0]u=GD%  
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try{ r;"uk+{i  
URL url = new URL(sURL); 0kiV-yc   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ij_h #f   
httpConnection.setRequestProperty("User-Agent","NetFox"); hLo>jE  
String sProperty = "bytes="+nStartPos+"-"; ,UA-Pq3}  
httpConnection.setRequestProperty("RANGE",sProperty); @&F\M}  
Utility.log(sProperty); T!ik"YZ@i  
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InputStream input = httpConnection.getInputStream(); ~]l T>|X  
//logResponseHead(httpConnection); C%ZSsp u  
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_  
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byte[] b = new byte[1024]; m`lxQik  
int nRead; :dML+R#Ymh  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) h4,S/n  
{ 9bb5?b/  
nStartPos += fileAccessI.write(b,0,nRead); L>X39R~  
//if(nThreadID == 1) VUbg{Rb)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k0>]7t$L  
} 8)m  
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){M)0,:  
Utility.log("Thread " + nThreadID + " is over!"); &`}8Jz=S  
bDownOver = true; T/YvCbo  
//nPos = fileAccessI.write (b,0,nRead); IPxK$nI^  
} \*r]v;NcP  
catch(Exception e){e.printStackTrace ();} Y5XhV;16  
} nu!tk$Q  
} +}Q@
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//打印回应的头信息 +=JJ=F)  
public void logResponseHead(HttpURLConnection con) W>2m%q U  
{ AfqthI$*m  
for(int i=1;;i++) H]a@"gO  
{ rD*CLqK  
String header=con.getHeaderFieldKey(i); ,f3Ck*
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if(header!=null) =(\xe| Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ](tv`1A,Wd  
Utility.log(header+" : "+con.getHeaderField(header)); ecqL;_{o  
else 1^R:[L4R`  
break; OLh QS_D  
} lE 09Y  
} fo5+3iu^  
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public void splitterStop() I7@g,~s  
{ "i1r9TLc  
bStop = true; NkYU3[m$v  
} >}|Vmy[/  
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} !3JYG  
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/* MET"s.v
 
**FileAccess.java "U6:z M  
*//文件访问(定位，写) +u[?8D7Y  
package NetFox; zSM;N^X8?  
import java.io.*; (Tbw@BFk  
5:6]ZFW  
`xm4?6  
public class FileAccessI implements Serializable{ Ix1[ $
9  
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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 ^a?H"  
RandomAccessFile oSavedFile; \}9GK`oR  
long nPos; J[7|Ul1 <  
{I"`
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9! 6\8  
public FileAccessI() throws IOException ?=^M(TA;  
{ H6! <y-
  
this("",0); GJB=5nE  
} f6O5k8n  
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public FileAccessI(String sName,long nPos) throws IOException X GhV? tA  
{ I6B4S"Q5<  
oSavedFile = new RandomAccessFile(sName,"rw"); cPL]
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this.nPos = nPos; qL1d-nH  
oSavedFile.seek(nPos); dXvp-oi  
} kIlK"=  
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public synchronized int write(byte[] b,int nStart,int nLen) I,0Z* rw  
{ ,U?W  
int n = -1; 6~b]RZe7  
try{ cV+x.)a.  
oSavedFile.write(b,nStart,nLen); w\f>.N  
n = nLen; WymBjDos:  
} YnLwBJ2i  
catch(IOException e) L^Q q[>  
{ rh%-va9  
e.printStackTrace (); PRi3=3oF  
} H6Qb]H.C  
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return n; UC{Tmf  
} M!nwcxB!  
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-g`3;1EV^  
} Z-wvdw]$  
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/* v@KP~kp  
**SiteInfoBean.java ))z1T8  
*/ 48 |u{  
package NetFox; e_{!8u.+  
7HkQ|~zGT  
Tl2e?El;4  
public class SiteInfoBean { A0hfy|1#L  
?5
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private String sSiteURL; //Site's URL 4X^{aIlshk  
private String sFilePath; //Saved File's Path _#mo6')j  
private String sFileName; //Saved File's Name v7kR]HU[y  
private int nSplitter; //Count of Splited Downloading File hExw}c  
{#Vck\&  
^3:y<{J  
public SiteInfoBean() oF9c>^s  
{//nSplitter的缺省值为5 ./!6M  
//default value of nSplitter is 5 _s> ZY0  
this("","","",5); %C^%Oq_k  
} OYC\+ =  
4EB&Zmg[K  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |>2IgTh1a  
{ zLa3Q\T  
sSiteURL= sURL; [Q+qu>&HB7  
sFilePath = sPath; RaNz)]+7`  
sFileName = sName; ".=LzjE<gv  
this.nSplitter = nSpiltter; 5W29oz}-S  
ag \d4y6  
Y=-ILN("  
} rW&#Xw/a  
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public String getSSiteURL() B,Gt6cUq  
{ *~0Ko{Avc  
return sSiteURL; ]XAJ|[]sj*  
} %}*0l8y  
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0D*uZ,oBEw  
public void setSSiteURL(String value) eyLVu.  
{ +u
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sSiteURL = value; 7?O~3  
} s?2DLXv}!  
m@_m"1_;  
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public String getSFilePath() V>2mzc  
{ 0B;cQSH!q  
return sFilePath; s, 8a1o  
} O!c b-  
Qf}^x9'  
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public void setSFilePath(String value) 3hrODts  
{ UOg4
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sFilePath = value; H%*<t}  
} MGmUgc  
E9yBa=#*c  
3Q@HP;<  
public String getSFileName() Q6|~ks+Y  
{ q~K KN /N  
return sFileName; =c>w  
} guC7!P^  
4p%=8G|  
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public void setSFileName(String value) !w[io;  
{ %!>~2=Q2*  
sFileName = value; _Wjd`*  
} p FkqDU  
!QB(M@1  
0K&\5xXM  
public int getNSplitter() v.ftfL!  
{ &!kr&g#]  
return nSplitter; =eXJZPR  
} ( _{\tgSm  
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"^~>aVuXf  
public void setNSplitter(int nCount) Pc*+QtQ  
{ bLfbzkNV\1  
nSplitter = nCount; "F*'UfOwrZ  
} @?w8XHEa|  
} UBUZ}ZIbN  
pzMli^  
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/* qQ_o>+3VAy  
**Utility.java :V%XEN)  
*/ UO& p2   
package NetFox; JERWz~n}  
.i7bI2^  
^r7-|  
public class Utility { J:YFy-[w(  
\y-Lt!}  
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public Utility() IkU:D"n7  
{ I#]$H#}Av  
l1RpG"  
r`Qzn" H  
} `z=I}6){  
ml|[xM8  
//线程睡眠 \?bp^BrI  
public static void sleep(int nSecond) (]Z$mv!  
{ [S}o[v\  
try{ e6n^l$'  
Thread.sleep(nSecond); _%)v9}D  
} %#.HFK  
catch(Exception e) 4DL;/Z:  
{ .Jt&6N  
e.printStackTrace (); =Of!1TR(  
} *N0R3da  
} 1,p[4k~Ww  
S >PTD@  
//日志 Lmy ^/P%  
public static void log(String sMsg) O MEPF2:  
{ H-Uy~Ry*T  
System.err.println(sMsg); WH.5vrY Z  
} M~/%V NX  
0Wf,SYx`s  
}Om+,!_d  
public static void log(int sMsg) TB]Bl.  
{ {=AK|  
System.err.println(sMsg); s^nwF>  
} MS
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} n')#]g0[  
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$lj1924?^  
/* u3 mTsq!  
**TestMethod.java 3f`+-&|M  
*/ UGy~Ecv  
package NetFox; vG'JMzAm  
<t{T]i+  
v'C`;I  
public class TestMethod { !O=J8;oLk  
Wmp,,H  
FDB^JH9d  
public TestMethod() nj*B-M\p  
{ ///xx/weblogic60b2_win.exe OT_w<te  
try{ 9w -t9X>X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _5^p+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (;o,t?:d  
SiteFileFetch fileFetch = new SiteFileFetch(bean); T4`.rnzyRb  
fileFetch.start(); 6g*B=d(j  
} ~M 6^%  
catch(Exception e){e.printStackTrace ();} Kq|L:Z  

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1.]Py"@:  
} $/%|0tQ  
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2\ /(
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public static void main(String[] args) =N,Mmz%  
{ So*Q8`"-.  
new TestMethod(); klG]PUzd  
} 3S-nsMs.  
} JJ3(0 +  
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