http断点续传简单实现（java)

/* k&yQ98H$K"  
**SiteFileFetch.java p?}f|mQS)  
*/ '^e0Ud,  
package NetFox; hI*`>9l  
import java.io.*; QjI#Cs}w  
import java.net.*; b/z'`?[  
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public class SiteFileFetch extends Thread { CcBQo8!G  
 ccRlql(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean o1Ne+Jt  
long[] nStartPos; //开始位置 ~KJ,SLzhx9  
long[] nEndPos; //结束位置 @51z-T  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 l+|1G  
long nFileLength; //文件长度 XMomFW_@  
boolean bFirst = true; //是否第一次取文件 KuIkul9^%  
boolean bStop = false; //停止标志 d8rBu jT  
File tmpFile; //文件下载的临时信息 h>~jQ&\M  
DataOutputStream output; //输出到文件的输出流 Fs?( UM  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F ~*zC`>Y  
public SiteFileFetch(SiteInfoBean bean) throws IOException s;anP0-O  
{ O5ucI$s  
siteInfoBean = bean; =sxkrih  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J0&zb'1  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Tc9&mKVE%(  
if(tmpFile.exists ()) n'q aR<bY  
{ $I\))*a  
bFirst = false; d:A\<F  
read_nPos(); ^g}L`9fL  
} rFf:A-#l  
else jMTRcj];(  
{ 52da]BW<  
nStartPos = new long[bean.getNSplitter()]; uPI v/&HA  
nEndPos = new long[bean.getNSplitter()]; K/!/M%GB6  
} )gr}<}X)B  
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} \)FeuLGL9  
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public void run() Jw2B&)k/  
{ Ga]47pQ"F  
//获得文件长度 d#E(~t(^  
//分割文件 `Q:de~+AM{  
//实例FileSplitterFetch H~~7~1"x  
//启动FileSplitterFetch线程 {k kAqJ  
//等待子线程返回 lt }r}HM+  
try{ ;+TMx(  
if(bFirst) 7
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{ &\JK%X.Jlt  
nFileLength = getFileSize(); /TzNdIv  
if(nFileLength == -1) %=laY_y G  
{ 976E3u"Vt  
System.err.println("File Length is not known!"); KX0<j  
} AEB/8%l};v  
else if(nFileLength == -2) gmXy>{T  
{ vEu Ka<5  
System.err.println("File is not access!"); xylpiSJ  
} [Bl $IfU  
else E~'q?LJOB  
{ 1,m\Q_  
for(int i=0;i<nStartPos.length;i++) ) ~ l\  
{ VI(RT-S6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >`<Ued  
} Mr$# e  
for(int i=0;i<nEndPos.length-1;i++) aeEw#  
{ 3Cq6h;!#  
nEndPos = nStartPos[i+1]; ^RYn8I  
} );0<Odw%.  
nEndPos[nEndPos.length-1] = nFileLength; d\v$%0  
}
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} <FCj
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//启动子线程 $Sp*)A]E`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; u)<Ysx8G  
for(int i=0;i<nStartPos.length;i++) !S
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{ |z.Gh1GCy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $ \? N<W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), x, G6\QmA  
nStartPos,nEndPos,i); i}.{m Et  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qzuQq94k  
fileSplitterFetch.start(); it(LphB8  
} A~qW.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CnxK+1n
l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3$GY,B  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _
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nEndPos = " + nFileLength); /X(@|tk:  
// fileSplitterFetch[nPos.length-1].start(); @N,:x\  
N BV}4  
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//等待子线程结束 G3Idxs  
//int count = 0; Y}Am
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//是否结束while循环 ap Fs UsE  
boolean breakWhile = false; Gg 7WmL  
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while(!bStop) lcu("^{3  
{ ]jHh7> D  
write_nPos(); BNAguAxWo  
Utility.sleep(500); y#hga5  
breakWhile = true; <_##YSGh,  
}"F ?H:\  
F Q8RK~?`  
for(int i=0;i<nStartPos.length;i++) xi '72  
{ w$w>N(e  
if(!fileSplitterFetch.bDownOver) ovhC42i  
{ Z7tU0  
breakWhile = false; jxRF"GD  
break; 8@Egy%_  
} *(?U  
} :z0s*,QH  
if(breakWhile) ]_^"|RJ  
break; \_m\U.*  
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//count++; r1[E{Tpz  
//if(count>4) RB S[*D  
// siteStop();
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} 3::3r}g  
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System.err.println("文件下载结束！"); {]t\`fjrg  
} )GiFkG  
catch(Exception e){e.printStackTrace ();} Y9IJ  
} Cm,*bgX  
@<@R=aqE  
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//获得文件长度 =oL8d6nI  
public long getFileSize() YtwmlIar`  
{ \Dvl%:8  
int nFileLength = -1; @A~B ,  
try{ W~XV  
URL url = new URL(siteInfoBean.getSSiteURL()); oso1uAOfp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D..{|29,:  
httpConnection.setRequestProperty("User-Agent","NetFox"); N<#S3B?.  
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int responseCode=httpConnection.getResponseCode(); 9[epr+f  
if(responseCode>=400) Jcwh|w9D8  
{ Zu2m%=J`  
processErrorCode(responseCode); 9IS1.3  
return -2; //-2 represent access is error @{J!6YGh  
} N.fQ7z=Z(M  
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String sHeader; d-6sC@PB  
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for(int i=1;;i++) Zd[y+$>  
{ 2.fyP"P L  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); TIK/%T  
//Utility.log(in.readLine()); A%NK0j$;}  
sHeader=httpConnection.getHeaderFieldKey(i); `l[6rf_.  
if(sHeader!=null) 1S*8v7  
{ "4Vi=*2V  
if(sHeader.equals("Content-Length")) p6&LZ=tL3  
{ htUy2v#V  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); h/0<:eZ*  
break; w%i+>\tO  
} p=8M0k  
} I2t-D1X  
else !#,-  
break; 8!`7-  
} E"9/YWv  
} B#qL$M,|  
catch(IOException e){e.printStackTrace ();} 38x[Ad4%  
catch(Exception e){e.printStackTrace ();} ^D]7pe  
9[t]]  
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Utility.log(nFileLength); 0UM@L }L  
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return nFileLength; }<5\O*kX4  
} b:}wR*Adc  
/I`cS
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//保存下载信息（文件指针位置） sx)$=~o  
private void write_nPos() KRnB[$3F1  
{  m+72C]9  
try{ 2R_opbw  
output = new DataOutputStream(new FileOutputStream(tmpFile)); C,OB3y  
output.writeInt(nStartPos.length); G<">/_jn  
for(int i=0;i<nStartPos.length;i++) *#prSS  
{ \28b_,i+  
// output.writeLong(nPos); ~# hE&nq  
output.writeLong(fileSplitterFetch.nStartPos); mR"2  
output.writeLong(fileSplitterFetch.nEndPos); M\Uc;:) H  
} Mv7w5vTl  
output.close(); FT3,k&i  
} ~n8Oyr  
catch(IOException e){e.printStackTrace ();} PK.h E{R  
catch(Exception e){e.printStackTrace ();} {|Mxvp*Hg  
} xoz*UA
.  
|*]X\UE  
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//读取保存的下载信息（文件指针位置） &;NNUT>Q  
private void read_nPos() d!}jdt5
%  
{ xVHQ[I%  
try{ eu}:Wg2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i h`y0(<  
int nCount = input.readInt(); Pjj;.c 7_j  
nStartPos = new long[nCount]; Pq{YZMr  
nEndPos = new long[nCount]; 26('V `N  
for(int i=0;i<nStartPos.length;i++) evndw>  
{ t(z(-G|&  
nStartPos = input.readLong(); cjy0s+>>  
nEndPos = input.readLong(); n7`.<*:  
} Sq?6R}q%  
input.close(); >n$EeJ  
} ;4S [ba1/  
catch(IOException e){e.printStackTrace ();} ?v
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catch(Exception e){e.printStackTrace ();} $X.'W\o|  
} hIzPy3  
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private void processErrorCode(int nErrorCode) QRg"/62WCD  
{ /\3XARt  
System.err.println("Error Code : " + nErrorCode); =CG!"&T  
} \K_!d]I {  
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//停止文件下载 st'?3A  
public void siteStop() nI|Lx`*v  
{ GH; F3s  
bStop = true; O'&X aaZV  
for(int i=0;i<nStartPos.length;i++) fdCxMKlu;  
fileSplitterFetch.splitterStop(); <Hr@~<@~  
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} W(PW9J9  
} W"}*Q-8W  
//负责部分文件的抓取 <4!&iU+;  
**FileSplitterFetch.java N8L)KgM5#7  
*/ V"2AN3~&  
package NetFox; H,4,~lv|  
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import java.io.*; :hl}Zn~jt  
import java.net.*; qRP8dH  
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public class FileSplitterFetch extends Thread { i/O,`2  
&' Nk2{  
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String sURL; //File URL j9L+.UVI,  
long nStartPos; //File Snippet Start Position v;F+fOo  
long nEndPos; //File Snippet End Position T h- vG  
int nThreadID; //Thread's ID 9^Vx*KVrU  
boolean bDownOver = false; //Downing is over d@>k\6%j  
boolean bStop = false; //Stop identical a,0o{*(u$  
FileAccessI fileAccessI = null; //File Access interface ?w5nKpG#RI  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nE"b`  
{ .}hZ7>4-  
this.sURL = sURL; E*T84Jh6  
this.nStartPos = nStart; g!kRa.`u1  
this.nEndPos = nEnd; -Bwu$$0  
nThreadID = id; e,j?_p  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $RF
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} G/RheH G  
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public void run() E6^S2J2  
{ tgF(=a]o  
while(nStartPos < nEndPos && !bStop) @Ozf}}#  
{ yV]-Oa$*s0  
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try{ ##+8GLQM  
URL url = new URL(sURL); WbDC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ofrlTw&o  
httpConnection.setRequestProperty("User-Agent","NetFox"); $d??(  
String sProperty = "bytes="+nStartPos+"-"; )i6U$,]  
httpConnection.setRequestProperty("RANGE",sProperty); kq.R(z+  
Utility.log(sProperty); F0ivL`  
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InputStream input = httpConnection.getInputStream(); |s3HeY+Co  
//logResponseHead(httpConnection); PA-0FlV|  
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byte[] b = new byte[1024]; HOQ _T4  
int nRead; FLnAN;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) wM&x8 <  
{ fvBC9^3  
nStartPos += fileAccessI.write(b,0,nRead); *1$~CC7  
//if(nThreadID == 1) .LTFa.jxA  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hpi_0lMkI  
} #pn AK  
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Utility.log("Thread " + nThreadID + " is over!"); E~O>m8hF  
bDownOver = true; )I UWM  
//nPos = fileAccessI.write (b,0,nRead); .N><yQ-j3'  
} +5}T!r  
catch(Exception e){e.printStackTrace ();} |(w#NE5  
} ;<)-*?m9  
} FCB/FtI0  
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//打印回应的头信息 8RT0&[  
public void logResponseHead(HttpURLConnection con) P:h4  
{ (Gk]<`d#N  
for(int i=1;;i++) G@I_6cE  
{ T^H) lC#R  
String header=con.getHeaderFieldKey(i); Xqva&/-  
if(header!=null) J1ro
\"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1#_j6Q2  
Utility.log(header+" : "+con.getHeaderField(header)); nz?BLO=  
else /Ta0}Y(y  
break; 3)MM5 bb$  
} EsxTBg  
} ~S{\wL53  
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public void splitterStop() (']z\4o  
{ exN#!&;  
bStop = true; oW1olmpp=  
} k.R/X  
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} ZTz(NS EK  
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/* QS?9&+JM|  
**FileAccess.java
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*//文件访问(定位，写) Y~?YA/.x  
package NetFox; |BWK"G  
import java.io.*; H9m2Whq  
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public class FileAccessI implements Serializable{ eOO*gM=  
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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 U~@B%Msb L  
RandomAccessFile oSavedFile; Fm~}A4  
long nPos; mNB ]e5;N  
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public FileAccessI() throws IOException b
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{ ) G&3V  
this("",0); p.Yg-CA  
} _BaS\U%1(  
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public FileAccessI(String sName,long nPos) throws IOException X"59`Yh  
{ @9
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oSavedFile = new RandomAccessFile(sName,"rw"); ?O^:j!C6  
this.nPos = nPos; qGUe0(
  
oSavedFile.seek(nPos); <.XoC?j  
} ,(?4T
~  
RwHXn]
1  
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public synchronized int write(byte[] b,int nStart,int nLen) j~> #{"C  
{ %Ne>'252y  
int n = -1; X
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try{ I}3K,w/7mi  
oSavedFile.write(b,nStart,nLen); *Z(C')7r  
n = nLen; 9 f/tNQ7W  
} e';c8WF3E  
catch(IOException e) EB<tX`Wp  
{ f3|=T8"t  
e.printStackTrace (); Q#bo!]H{t  
} :#KURYO<  
}+Z;zm@/6  
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return n; &,|uTIs  
} 9:5NX3"p  
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} @D{[Hj`<  
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?  
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/* ;8kfgpM_  
**SiteInfoBean.java )Em,3I/.l  
*/ o
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package NetFox; Li$k<AM  
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public class SiteInfoBean { 0kEq|k9  
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private String sSiteURL; //Site's URL 'm((G4  
private String sFilePath; //Saved File's Path *Y?]="8c#;  
private String sFileName; //Saved File's Name f 8U;T$)  
private int nSplitter; //Count of Splited Downloading File j0M;2 3@[  
</Lqk3S-!  
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public SiteInfoBean() ?7s
  
{//nSplitter的缺省值为5 0']M,iC/  
//default value of nSplitter is 5 ^<b.j.$<z  
this("","","",5); +g30frg+Gl  
} 5lY9  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |Q+v6r(<zZ  
{ yU`IyaazZ  
sSiteURL= sURL;
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sFilePath = sPath; N.rB-  
sFileName = sName; pp_ddk  
this.nSplitter = nSpiltter; l)bUHh5[  
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bsVOO9.4-  
} pYQs|5d  
sIM`Q%  
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public String getSSiteURL() ;^]F~x}  
{ r73Xh"SL  
return sSiteURL; t?Znil|o  
} RmCR"~  
*()#*0  
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public void setSSiteURL(String value) / nR
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{ '?4[w]0J<  
sSiteURL = value; :eO0{JN4T  
} nQC[[G*x  
s=+
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public String getSFilePath() 5lbh "m=  
{ I}{eYXh  
return sFilePath; 0U~JSmj:2K  
} ]|(?i ,p  
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public void setSFilePath(String value) C<ljBz`,t  
{ ~a Rq\fx{  
sFilePath = value; Ja2.1v|r.  
} nwYeOa/t  
v4zARE9#  
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public String getSFileName()
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{ l0V@19Ec  
return sFileName; 0&@6NW&Mu  
} +ZO*~.zZ  
,$>Z= ~x*  
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public void setSFileName(String value) sy?W\(x  
{ fC[gu$f][  
sFileName = value; CJ>=odK[  
} O jmz/W  
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2J5dZYW  
public int getNSplitter() aY~IS?!;  
{ 'Z[R*Ikzq  
return nSplitter; dEnhNPeRl  
} *BV .zbGm  
#;)7~69  
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public void setNSplitter(int nCount) >'eqOZM  
{ 78"W ~`8  
nSplitter = nCount; VrG|/2  
} !.A>)+AK  
} SE1 tlP  
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/* H+Wd#7l,  
**Utility.java .0 K8h:I  
*/ 0 N(2[s_A  
package NetFox; -$rfu  
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public class Utility { &W%TY:Da|  
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!E8JpE|z#  
public Utility() ,$Mw/fA  
{ :d;5Q\C`  
2t'&7>Ys{  
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} @QEVl
 
&nss[w$%C  
//线程睡眠 gVc[`(@h  
public static void sleep(int nSecond) 0qv)'[O  
{ gDrqs>8  
try{ Lv"83$^S9  
Thread.sleep(nSecond); W~qo `r  
} )8_0d)  
catch(Exception e) 7g$t$cZby,  
{ QZY(S*Up  
e.printStackTrace (); VmW_,  
} b({2|R  
} cjL!$OE6  
;%)i/MGEB  
//日志 XpGom;z^c  
public static void log(String sMsg) [O3R(`<e5  
{ F^f]*MhT"  
System.err.println(sMsg); z)0F
k  
} LImD]e
`  
sdY6_HtE  
!dGgLU_  
public static void log(int sMsg) 9D bp`%j  
{ Kr<O7t0X  
System.err.println(sMsg); 6\bbP>ql  
} s}.nh>Q  
} AxeWj%w@  
>/>a++19  
hN.#ui5 $  
/* R#t~i&v/  
**TestMethod.java psMagzr&)e  
*/ 4xlsdq8`t  
package NetFox; &HE8O}<>  
REJ}T:  
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public class TestMethod { >TE&myZ?*  
biJU r^n  
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public TestMethod() 5H79) n>  
{ ///xx/weblogic60b2_win.exe OygYP  
try{ ?E`J-ncP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); myYe~f4=HQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9'tM65
K  
SiteFileFetch fileFetch = new SiteFileFetch(bean); mb#)w`<  
fileFetch.start(); !#r]f9QP  
}  iJ\#su  
catch(Exception e){e.printStackTrace ();} i-Z@6\/a5  
D@Q|QY5qic  

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} pyNPdEy  
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public static void main(String[] args) {BJxRH"&6*  
{ ELm#  
new TestMethod(); hZpFI?lqc\  
} []@Mk  
} zIL.R#|D=  
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