http断点续传简单实现（java)

/* "@B!5s0  
**SiteFileFetch.java  N>`+{  
*/ FW7+!A&F  
package NetFox; *
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import java.io.*; etf ft8  
import java.net.*; =1^a/  
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public class SiteFileFetch extends Thread { X@+:O-$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean D,xWc|V  
long[] nStartPos; //开始位置 yP0P-8  
long[] nEndPos; //结束位置 Y=X"YH|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 pALB[;9g  
long nFileLength; //文件长度 WAY<X:|We  
boolean bFirst = true; //是否第一次取文件 V$ 38  
boolean bStop = false; //停止标志 V.WfP*~NJ  
File tmpFile; //文件下载的临时信息 CkoPno  
DataOutputStream output; //输出到文件的输出流 N(Y9FD;H  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） NOyLZa'  
public SiteFileFetch(SiteInfoBean bean) throws IOException :&yRvu  
{ PB>p"[ap4  
siteInfoBean = bean; v ;MI*!E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); t)XV'J  
if(tmpFile.exists ()) 6(9Ta'ywZ  
{ ^S ,E"Q  
bFirst = false; &4*&L.hPM^  
read_nPos(); CcY.8|HT  
} md$[Bs9  
else } Q1$v~  
{  p<*-B  
nStartPos = new long[bean.getNSplitter()]; 1)_f9GR  
nEndPos = new long[bean.getNSplitter()]; 
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} ?P`wLS^;  
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} R5]R pW=G  
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public void run() |D]jdd@!a2  
{ FGwz5@|E  
//获得文件长度 D{N1.rSxv  
//分割文件 3kR- WgVF,  
//实例FileSplitterFetch !c6lP'U  
//启动FileSplitterFetch线程 m.K"IXD  
//等待子线程返回 {h9#JMIA  
try{ 9k7|B>LT  
if(bFirst) Dj!J 4uD  
{ \!cqeg*53  
nFileLength = getFileSize(); :\80*[=;Z  
if(nFileLength == -1) pbqa  
{ &}T`[ d_Z  
System.err.println("File Length is not known!"); |lJXI:GG  
} AZl=w`;/O%  
else if(nFileLength == -2) uU5:,Wy+dg  
{ [*}[W6 3v  
System.err.println("File is not access!"); "#4PU5.  
} P:*'x9`  
else {+C>^b  
{ g"T~)SQP  
for(int i=0;i<nStartPos.length;i++) U +mx@C_  
{ {ReAl_Cm  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); m@zxjIwT  
} %J|EDf,M  
for(int i=0;i<nEndPos.length-1;i++) _&F6As !{  
{ |;D[Al5AMc  
nEndPos = nStartPos[i+1]; f2{4Y)  
} :nwcO3~`  
nEndPos[nEndPos.length-1] = nFileLength; U Ciq'^,  
} i6X/`XW'  
} Pi8U}lG;  
6eS#L21*  
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//启动子线程 q>Q|:g&:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
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for(int i=0;i<nStartPos.length;i++) |fw+{f  
{ "%.#/!RG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -TD6s:'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), CiMy_`H  
nStartPos,nEndPos,i); 5T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c89RuI `B~  
fileSplitterFetch.start(); 5mFi)0={y  
} :_e.ch:4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ax3:rl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q]|+Y0y}X  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .qVdo+M%F  
nEndPos = " + nFileLength); VWMCbg>R  
// fileSplitterFetch[nPos.length-1].start(); LZoth+:  
x%(!+  
ikxSWO_Y=  
//等待子线程结束 hG ]jm  
//int count = 0; |Pj _L`G  
//是否结束while循环 Y/$SriC_+'  
boolean breakWhile = false; _8S).*  
J@Orrz2q#  
% tJ?dlD'  
while(!bStop) X`aED\#\h  
{ .7kVC  
write_nPos(); #); 6+v  
Utility.sleep(500); i5AhF\7F9  
breakWhile = true; [0~qs|27  
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for(int i=0;i<nStartPos.length;i++) #Kh`ATme  
{ Mq7|37(N[  
if(!fileSplitterFetch.bDownOver) #JW1JCT  
{ EAq >v t83  
breakWhile = false; 1gt[_P2u  
break; d@w I: 7  
} {==Q6BG*  
} qkBnEPWZy  
if(breakWhile) qb9%Y/xy  
break; WYh7Y  
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19=Dd#Nf  
//count++; s
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//if(count>4) 3;M!]9ms  
// siteStop(); 3$kZu  
} &G"]v]V  
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System.err.println("文件下载结束！"); -~-2 g  
} '{+hti,Lh  
catch(Exception e){e.printStackTrace ();} _rR.Y3N  
} a%]p*X!  
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//获得文件长度 P`oR-D  
public long getFileSize() D=OU61AA  
{ >N3
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int nFileLength = -1; MD On; Af>  
try{ A9R}74e4g  
URL url = new URL(siteInfoBean.getSSiteURL()); 3n/L;T,X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g_x<+3a  
httpConnection.setRequestProperty("User-Agent","NetFox"); Zg'[.wov  
2 43DdIG$  
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int responseCode=httpConnection.getResponseCode(); [cH/Y2[  
if(responseCode>=400) {otvJ|'N  
{ ~Ep
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processErrorCode(responseCode); I&vB\A  
return -2; //-2 represent access is error ~kHir]jc
 
} ;zOZu~Q|'  
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String sHeader; S2NsqHJr  
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for(int i=1;;i++) ~q4y'dBy*  
{ [6Wr t8"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); EtL=_D-  
//Utility.log(in.readLine()); 4-"wFp  
sHeader=httpConnection.getHeaderFieldKey(i); XmnqZWB  
if(sHeader!=null) IX>|bA;  
{ Y.73I83-j  
if(sHeader.equals("Content-Length")) 3LTO+>, |"  
{ '|cuVxcE55  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); B8nXWi  
break; cshUxabB  
} td m{ V st  
} 1dq.UW\  
else 2KG j !w  
break; p<+]+,|\~:  
} f*I5m=  
} F;ZLoG*U  
catch(IOException e){e.printStackTrace ();} yjpjJ  
catch(Exception e){e.printStackTrace ();} G]SE A  
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Utility.log(nFileLength); ;klDt|%3j  
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return nFileLength; d}G?iX;c}  
} U!'l
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=MXF`k^}  
//保存下载信息（文件指针位置） *K)v&}uw  
private void write_nPos() r" D|1  
{ \xdt|:8  
try{ 3xe8DD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0g+@WK6y  
output.writeInt(nStartPos.length); UtutdkaS  
for(int i=0;i<nStartPos.length;i++) dnx}c4P  
{ F>M$|Sc2  
// output.writeLong(nPos); zPmVECS  
output.writeLong(fileSplitterFetch.nStartPos); d!d 3r W;A  
output.writeLong(fileSplitterFetch.nEndPos); ^Y&Cm.w  
} VgdkCdWRm_  
output.close(); Q(sbClp"  
} ;L[9[uQ[C  
catch(IOException e){e.printStackTrace ();}  Ntqc=z  
catch(Exception e){e.printStackTrace ();} UqHOS{\Sz  
} Z 0:2x(x9  
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. 9 NS  
//读取保存的下载信息（文件指针位置） 9j 8t<5s  
private void read_nPos() OBl8kH(b>  
{ ZMe|fn  
try{ 3x'30  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); X+3)DE\2  
int nCount = input.readInt(); )&9=)G  
nStartPos = new long[nCount]; N!v@!z9Mu  
nEndPos = new long[nCount]; ArEpH"}@  
for(int i=0;i<nStartPos.length;i++) y(R*Z^c}d,  
{ !G,$:t1-=V  
nStartPos = input.readLong(); ^Pf&C0xXv  
nEndPos = input.readLong(); Fv: %"P^  
} h<M7[p=  
input.close(); 98]t"ny [  
} 0 mQ3P.9  
catch(IOException e){e.printStackTrace ();} HB}gn2.1&  
catch(Exception e){e.printStackTrace ();} $7r wara  
} KH7]`CU  
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private void processErrorCode(int nErrorCode) o`U\Nhq  
{ JA}'d7yEa  
System.err.println("Error Code : " + nErrorCode); ? 1{S_  
} @
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KCu6:)6'  
^ZlV1G;/W@  
//停止文件下载 -7$'* V9$  
public void siteStop() {q)B@#p
 
{ JXAyF6 $  
bStop = true; zJ:r0Bt  
for(int i=0;i<nStartPos.length;i++) &>jkfG  
fileSplitterFetch.splitterStop(); C{Ug ?hVP  
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} CJOl|"UyJ  
} ]aRD6F:L  
//负责部分文件的抓取 qWpCe*C  
**FileSplitterFetch.java &V3oW1*W  
*/ gdK/:%u3  
package NetFox; *N r|G61  
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import java.io.*; /R
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import java.net.*; Yel(}Ny  
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public class FileSplitterFetch extends Thread { Bg
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String sURL; //File URL C6M/$_l&a  
long nStartPos; //File Snippet Start Position `.W;ptZ6  
long nEndPos; //File Snippet End Position [8P2V  
int nThreadID; //Thread's ID xW9 s[X  
boolean bDownOver = false; //Downing is over X
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boolean bStop = false; //Stop identical WS/+Yl  
FileAccessI fileAccessI = null; //File Access interface %`1vIr(7  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException UK>=y_FYO  
{ SU'9+=_$  
this.sURL = sURL; xUpb1R  
this.nStartPos = nStart; \#jDQ  
this.nEndPos = nEnd; /&d`c=nH  
nThreadID = id; }?J5!X  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 RM1uYFs<  
} CD1=2  
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/A.i5=k  
public void run() /&:9
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{ UMwMXmZNJ  
while(nStartPos < nEndPos && !bStop) ~ p.W*skD  
{ k#5e:VOb  
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}.) 43(>]  
try{ 4_I{Q^f  
URL url = new URL(sURL); d`<^+p)oy  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =k=2~ j  
httpConnection.setRequestProperty("User-Agent","NetFox"); YiuOu(X  
String sProperty = "bytes="+nStartPos+"-"; pf@}4PN}  
httpConnection.setRequestProperty("RANGE",sProperty); %`'z^W  
Utility.log(sProperty); )xx/di  
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InputStream input = httpConnection.getInputStream(); Q3%# o+R>  
//logResponseHead(httpConnection); h;p%EZ  
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byte[] b = new byte[1024]; %Dls36F  
int nRead; z~e~K`S  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /_OZ1jX  
{ ;T
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nStartPos += fileAccessI.write(b,0,nRead); <`_OpNxqW  
//if(nThreadID == 1) niEEm`"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fKz"z{\,0  
} {kl{mJ*  
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Utility.log("Thread " + nThreadID + " is over!"); ';\gR/L  
bDownOver = true; <GgtP55  
//nPos = fileAccessI.write (b,0,nRead); u?3NBc$~A  
} B=bI'S8\  
catch(Exception e){e.printStackTrace ();} F2`htM@,  
} '#i]SU&*  
} AOx3QgC^NO  
0 ;_wAk  
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//打印回应的头信息 _#D\*0J  
public void logResponseHead(HttpURLConnection con) d<Q+D1  
{ iynS4
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for(int i=1;;i++) EKd3$(^  
{ rKQASRF5*  
String header=con.getHeaderFieldKey(i); px}7If  
if(header!=null) U?F^D4CV\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); hY= s9\  
Utility.log(header+" : "+con.getHeaderField(header)); JM-ce8U  
else ?)[zLnxc&  
break; J&"?m.~@  
} vMX6B
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} dHq )vs,L  
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public void splitterStop() #}!>iFBcH  
{ r d6F"W  
bStop = true; Ls>u`hG  
} 8yWu{'G
 
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} R=amKLD?  
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/* t&9as}  
**FileAccess.java 'y6!%k*  
*//文件访问(定位，写) {y&\?'L'  
package NetFox; a()6bRc~T  
import java.io.*; BgkB x  
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public class FileAccessI implements Serializable{ g|._n  
-Y8ks7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 rO(TG  
RandomAccessFile oSavedFile; (~7m"?  
long nPos; Z<N&UFw7QJ  
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public FileAccessI() throws IOException up
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{ d
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this("",0); Im?= e  
} (~G5t(+  
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public FileAccessI(String sName,long nPos) throws IOException :m*!?QGdL  
{ Tr+h$M1_Ja  
oSavedFile = new RandomAccessFile(sName,"rw"); S!jF:Uc
 
this.nPos = nPos; 5 dfe@$  
oSavedFile.seek(nPos); N[,VSO&  
} :kb1}Wu  
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public synchronized int write(byte[] b,int nStart,int nLen) N753  
{ &e-#|p#v  
int n = -1; Z6IJo%s  
try{ lrs0^@.+  
oSavedFile.write(b,nStart,nLen); d2C[wQF  
n = nLen; }fJ:wku  
} rnn2u+OG  
catch(IOException e) {d1N&  
{ QiTR-M2C!  
e.printStackTrace (); GUu\dl9WA'  
} ~?AC:  
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return n; 3$?9uMl#  
} S2rEy2\}:  
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} c~gNH%1XN  
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/* }BI~am_  
**SiteInfoBean.java ,DQGv_  
*/ L$Hx?^3  
package NetFox; z(g%ue\  
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[&h#iTRT  
public class SiteInfoBean { Io$w|~x  
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private String sSiteURL; //Site's URL J3/\<=Qh  
private String sFilePath; //Saved File's Path [x;(cISK1  
private String sFileName; //Saved File's Name Ku<b0<`  
private int nSplitter; //Count of Splited Downloading File bz,Da  
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public SiteInfoBean() 5^/,aI  
{//nSplitter的缺省值为5 E4sn[DO  
//default value of nSplitter is 5 J)9 AnGWe  
this("","","",5); "/ tUA\=j  
} wGEWr2$  
#4P8
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ==%`e/~Y  
{ .S~@BI(|<  
sSiteURL= sURL; L;/9L[s,  
sFilePath = sPath; LP.HS'M~u  
sFileName = sName; Sm$p\ORa  
this.nSplitter = nSpiltter; h5L=M^z!>  

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} U7^7/s/.  
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public String getSSiteURL() \hs/D+MCk  
{ YV5Yx-+3w$  
return sSiteURL; l6iw=b[?  
} 8)L'rW{q#  
EzR%w*F>Q  
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public void setSSiteURL(String value) 89hF)80  
{ 2dHM  
sSiteURL = value; u?Fnlne4@  
} qBT_! )h   
&MCy.(jN  
L +L9Y}  
public String getSFilePath() ;tJWOm  
{ :]vA2  
return sFilePath; iV5}U2Vh  
} sW }<zGYd  
5\okU"{d7  
8]S,u:E:N  
public void setSFilePath(String value) !n|#|.0m  
{ EJ1Bq>u7  
sFilePath = value; ARPKzF`Wq  
} z)}3**3'y  
j7K5SS_]  
k/%#>  
public String getSFileName() 59V#FW
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{ OkLz^R?d  
return sFileName; 3)}(M
 
} W%TQYR  
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public void setSFileName(String value) 2b5#PcKa  
{ @&;(D!_&  
sFileName = value; Z+ixRch@-s  
} v2d<o[[C  
?-pi,O~(p  
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public int getNSplitter() )D;*DUtMVm  
{ ~e{H#*f&1/  
return nSplitter; Rq) 0i}F  
} d^PD#&"g  
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S@x}QQ|.  
public void setNSplitter(int nCount) UEzsDJu  
{ C;9t">prk  
nSplitter = nCount; ny)]GvxI  
}
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} QIQfI05  
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q
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/* u#1%P5r&X  
**Utility.java ]Kv q
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*/ k}GjD2m  
package NetFox; ^K+:C;Q|  
y,Jh@n';|  
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public class Utility { +]c/&Xo!  
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public Utility() Jy]Id*u9  
{ KF+mZB  
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} uMvb-8  

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//线程睡眠 []zua14F6  
public static void sleep(int nSecond) 8'_ 0g[s  
{ 6gnbkpYi  
try{ &f-hG3/M  
Thread.sleep(nSecond); ND5$bq Nu?  
} \@K
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catch(Exception e) gw^'{b  
{ V>Fesm"aq  
e.printStackTrace (); WWNu:,  
} kx:j
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} ?R|th Z  
W m . }Zh  
//日志 }x:0os  
public static void log(String sMsg) -p`L%xj\  
{ A?8\Y{FQ  
System.err.println(sMsg); *t(4 $  
} yoQ\lk  
C`QzT{6!  
iCP~
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public static void log(int sMsg) Pz%~ST  
{ a[sKE?  
System.err.println(sMsg); hd2'AlB  
} yzR=A%V8A  
} GKZN}bOm\  
?iv=53<c#  
:HRT 
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/* y(5:}x&E  
**TestMethod.java jZd}OC<  
*/ n*<v]1  
package NetFox; .po>qb6  
o_f-GO  
e\F}q)_
 
public class TestMethod { G>w+#{(  
ZSB?Y1wG  
l+zb~  
public TestMethod() vN65T$g7  
{ ///xx/weblogic60b2_win.exe n-J2/j  
try{ dz-y}J11  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
t>xd]ti  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7C7>y/uS  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7O)" `  
fileFetch.start(); 8AL\ST51x"  
} 6ZOy&fd,Ty  
catch(Exception e){e.printStackTrace ();} 1$pb (OK  
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} dU_
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public static void main(String[] args) lr~0p
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{ !l 6dg&
 
new TestMethod(); N|K4{Frm  
} uwmQ?LS]V  
} @MbVWiv  
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