http断点续传简单实现（java)

/* REa%kU  
**SiteFileFetch.java i"r=b%;;  
*/ =%bc;ZUu  
package NetFox; lps  
import java.io.*; 8`*(lKiL  
import java.net.*; #)XO,^s.  
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public class SiteFileFetch extends Thread { 8ciLzyrY*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8s|r'  
long[] nStartPos; //开始位置
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long[] nEndPos; //结束位置 ^s%Qt  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S_^
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long nFileLength; //文件长度 3p7*UVR"  
boolean bFirst = true; //是否第一次取文件 thOCzGJ$  
boolean bStop = false; //停止标志 p@P[pzxI  
File tmpFile; //文件下载的临时信息 X,~8) W  
DataOutputStream output; //输出到文件的输出流 4}gwMjU-B  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） GG7N!eZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException seJc,2Ex  
{ <>-UPRwqI  
siteInfoBean = bean; -i9/1.Z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); bju0l[;=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S6cSeRmw  
if(tmpFile.exists ()) I@.qon2V  
{ KExfa4W 3{  
bFirst = false; A1i-QG/6  
read_nPos(); DRw%~  
} l.C{Ar  
else O'(qeN<^w  
{ f3nib8B'  
nStartPos = new long[bean.getNSplitter()]; Y~Zg^x2  
nEndPos = new long[bean.getNSplitter()]; ])e6\)  
} i`
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} )Y)7p//  
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public void run() [<cP~  
{ YV0e)bf  
//获得文件长度
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//分割文件 !zD| @sX{  
//实例FileSplitterFetch GlVq<RG*  
//启动FileSplitterFetch线程 `,TPd ~#~  
//等待子线程返回 0ro)e~_@*  
try{ 3fpX  
if(bFirst) 75<E0O  
{ G.L4l|%W  
nFileLength = getFileSize(); {Ke3  
if(nFileLength == -1) i^j{l_-JE  
{ W&GDE  
System.err.println("File Length is not known!"); x'}{^'}/  
} m`n51
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else if(nFileLength == -2) !5x"d7  
{ WpRi+NC}ln  
System.err.println("File is not access!"); N+h|Ffnp  
} 5PdC4vI*+  
else x}72jJe`  
{ ;0@"1`  
for(int i=0;i<nStartPos.length;i++) 7v1}8Uk  
{ SxMh '  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @@}A\wA-  
} !SVW}Q=5#  
for(int i=0;i<nEndPos.length-1;i++) l~!#<=.  
{ @"Do8p!*(6  
nEndPos = nStartPos[i+1]; )TG\P,H9  
} {d=y9Jb^  
nEndPos[nEndPos.length-1] = nFileLength; %N>@( .  
} _M{m6k(h  
} sd Z=3)  
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//启动子线程 k5W5 9tz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $yRbo'-  
for(int i=0;i<nStartPos.length;i++) N/]TZu~k z  
{ ==Ju2D?%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f'*HP%+Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >[ywrB ?T  
nStartPos,nEndPos,i); c~@I1M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U.d*E/OR5  
fileSplitterFetch.start(); fFMG9]*  
} O`H[,+vm[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 350y6pVh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0s=GM|y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", wMei`svY  
nEndPos = " + nFileLength);
.3oFSc`q  
// fileSplitterFetch[nPos.length-1].start(); LTG/gif[u  
&9IMZAo  
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//等待子线程结束 tlG&PVvr  
//int count = 0; ;v#~o*  
//是否结束while循环  k:R9wo  
boolean breakWhile = false; LKztGfy  
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while(!bStop) s|YY i~  
{ -x5^>+Y4  
write_nPos(); o"K{^ L~u  
Utility.sleep(500); +n1}({7m  
breakWhile = true; *COr^7Kf5  
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for(int i=0;i<nStartPos.length;i++) [JsQ/|=z  
{ IB(5 &u.  
if(!fileSplitterFetch.bDownOver) N(/DC)DJg  
{ v-4eN1OS  
breakWhile = false; -,3Ka:  
break; ZJ u\  
} ^hTq~"  
} YgrBIul  
if(breakWhile) '^}l|(  
break; $:F]O$A  
*m2J$9q  
F71.%p7C8"  
//count++; Bglh}_X  
//if(count>4) ytr~} M%  
// siteStop(); <d
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} !)KX?i[Q  
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System.err.println("文件下载结束！"); cD]{ Nn  
} `[/BG)4  
catch(Exception e){e.printStackTrace ();} "?n~ /9`  
} hZ5h(CQ?"#  
o=4d2V%m  
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//获得文件长度 !dSt
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public long getFileSize() 3x.|g  
{ jcv3ES^  
int nFileLength = -1; \*1pFX#  
try{ Jc:*X4-'  
URL url = new URL(siteInfoBean.getSSiteURL()); .Mdxbs6.C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [u=b[(  
httpConnection.setRequestProperty("User-Agent","NetFox"); -i7W|X"  
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int responseCode=httpConnection.getResponseCode(); ,`)!K}2  
if(responseCode>=400) Sh}AGNE'  
{ eB^:+h#A_  
processErrorCode(responseCode); 8xZN4ck_@  
return -2; //-2 represent access is error lRX*\M\`  
} !$f@j6.  
f \[Z`D  
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String sHeader; jvCk+n[  
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for(int i=1;;i++) ;Rt?&&W  
{ )!e-5O49r  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2Cj?k.Zk  
//Utility.log(in.readLine()); +Q8Bin  
sHeader=httpConnection.getHeaderFieldKey(i); %v4/.4sR,;  
if(sHeader!=null) &=xm>;`3  
{ cdf8YN0!  
if(sHeader.equals("Content-Length")) gNo.&G [  
{ ~;3N'o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); LezM=om.  
break; $+R0RqV$V~  
} TCv}N0  
} iw
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else a<rk'4,8a  
break; sn]8h2z  
} lX;2~iW{/  
} Nq"/:3@4  
catch(IOException e){e.printStackTrace ();} X-e)w  
catch(Exception e){e.printStackTrace ();} W{?7Pn?1`  
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Utility.log(nFileLength); yv[s)c}  
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return nFileLength; WpWnwQY`#  
} :(!il?  
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//保存下载信息（文件指针位置） qR--lvO  
private void write_nPos() 7fgA)dU:K  
{ BOoLs(p  
try{ 0Zs}y\J`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BI3Q~ADV  
output.writeInt(nStartPos.length); MrXhVZ"d*  
for(int i=0;i<nStartPos.length;i++) )?:V5UO\  
{ dl6d!Nz*  
// output.writeLong(nPos); 1ZOHyO  
output.writeLong(fileSplitterFetch.nStartPos); |l 03,dOF  
output.writeLong(fileSplitterFetch.nEndPos); W52AX.Nm  
} mh2t ' O  
output.close(); d@8=%x:  
} w<|^i*  
catch(IOException e){e.printStackTrace ();} S=n,unn#t  
catch(Exception e){e.printStackTrace ();} ?ye)&  
} <9@I50;  
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//读取保存的下载信息（文件指针位置） NgaX&m`  
private void read_nPos() tT ~}lW)Y  
{ [kDjht|$>  
try{ wyMj^+ 2m  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .Qn54tS0q  
int nCount = input.readInt(); O\,n;oj  
nStartPos = new long[nCount]; [u[F6Wst  
nEndPos = new long[nCount]; l23_K7  
for(int i=0;i<nStartPos.length;i++) /o*r[g7<  
{ D ?1$I0=  
nStartPos = input.readLong(); xVao3+r  
nEndPos = input.readLong(); #Wey)DI  
} b?hdWQSW7  
input.close(); 7q<I7Wt  
} P%]li`56-c  
catch(IOException e){e.printStackTrace ();}  !NUsfd  
catch(Exception e){e.printStackTrace ();} lUJ/ nG0l  
} ]2T=%(*  
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private void processErrorCode(int nErrorCode) %fGS< W;  
{ R+ lwOVX  
System.err.println("Error Code : " + nErrorCode); ZqsI\
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} CLg;  
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//停止文件下载 k-@CcrepF  
public void siteStop() TPZZln'3   
{ ,[71,zs  
bStop = true; ,a9<\bd)  
for(int i=0;i<nStartPos.length;i++) (30{:o&^  
fileSplitterFetch.splitterStop(); ;;pxI5  
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} a)$"  
} ?%J{1+hY  
//负责部分文件的抓取 12M

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**FileSplitterFetch.java rhO ]4A  
*/ zRbooo{N  
package NetFox; O4ciD1  
, |CT|2D>  
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import java.io.*; {}H5%W  
import java.net.*; In#V1[io  
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public class FileSplitterFetch extends Thread { =W"BfG  
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* xdS<  
String sURL; //File URL lG;RfDI-  
long nStartPos; //File Snippet Start Position *G7$wW:?  
long nEndPos; //File Snippet End Position uvz}qH@j/Q  
int nThreadID; //Thread's ID V'sp6:3*\  
boolean bDownOver = false; //Downing is over b*S:wfw  
boolean bStop = false; //Stop identical ,'?%z>RZm  
FileAccessI fileAccessI = null; //File Access interface ER~m &JI  
4J Bm|Pf(  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <"Z]S^>$  
{ |v#N  
this.sURL = sURL; Adp:O"-H1o  
this.nStartPos = nStart; hPLQ)c?   
this.nEndPos = nEnd; ^B8%Re%  
nThreadID = id; }\k"azQ`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -Qgu6Ty  
} pRe, B'&  
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public void run() .<}(J#vC  
{ z1X
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while(nStartPos < nEndPos && !bStop) -} \g[|  
{ C2NJrg4(  
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try{ Dk
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URL url = new URL(sURL);
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )
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httpConnection.setRequestProperty("User-Agent","NetFox");  s.&ewf\  
String sProperty = "bytes="+nStartPos+"-"; C8>zr6)1  
httpConnection.setRequestProperty("RANGE",sProperty); S'#KPzy.  
Utility.log(sProperty); ye=*m  
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InputStream input = httpConnection.getInputStream(); xZZW*d_b  
//logResponseHead(httpConnection); Is&z~Xy/  
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byte[] b = new byte[1024]; GzxtC&  
int nRead; FZ'|z8Dm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <ek_n;R  
{ ":EfR`A#  
nStartPos += fileAccessI.write(b,0,nRead); aRPgo0,W1  
//if(nThreadID == 1) Z? u\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]`)50\pdw  
} Cy-q9uTm  
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Utility.log("Thread " + nThreadID + " is over!"); K-(k6<h  
bDownOver = true; ,6:ya8vB  
//nPos = fileAccessI.write (b,0,nRead); (yIl]ZN*  
} $o"Szy  
catch(Exception e){e.printStackTrace ();} V1 T?T9m  
} (1p[K-J)r  
} (oO*|\9u  
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//打印回应的头信息 ^vmT=f;TM  
public void logResponseHead(HttpURLConnection con) M>^Ho2  
{ {)nm {IV,  
for(int i=1;;i++) <cm,U)j2  
{ a]XQM$T$  
String header=con.getHeaderFieldKey(i); }w .[ZeP  
if(header!=null) Y^$^B,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o"dX3jd  
Utility.log(header+" : "+con.getHeaderField(header)); w=5D>]  
else X-&t!0O4}`  
break; # le<R  
} b-R!oP+vP  
} g((glr)6M  
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public void splitterStop() MUsF/1  
{ ka? |_(  
bStop = true; d7s? c  
} WtOpxAq  
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} S~fURn  
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/* (PAkKY}  
**FileAccess.java \cmt'b  
*//文件访问(定位，写) >a7'_n_o  
package NetFox; 1M+o7HO.mG  
import java.io.*; 4TcKs}z  
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 x~p8Mcv  
public class FileAccessI implements Serializable{ :ad  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _Kdqa%L !  
RandomAccessFile oSavedFile; _)s<E9t2N  
long nPos; hbm%{*d  
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public FileAccessI() throws IOException feM%-  
{ }= OI (Wy  
this("",0); c"`o V! m  
} 2z9\p%MX  
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public FileAccessI(String sName,long nPos) throws IOException e~C5{XEE  
{ Sq^f}q  
oSavedFile = new RandomAccessFile(sName,"rw"); _~V
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this.nPos = nPos; d 7vD  
oSavedFile.seek(nPos); 4FSA:]o-  
} I\djZG$s;N  
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)yvI {  
public synchronized int write(byte[] b,int nStart,int nLen) c'M#va  
{ k L\;90  
int n = -1;  u!I Es  
try{ sXHrCU  
oSavedFile.write(b,nStart,nLen); (IdXJvKU!  
n = nLen; EC(,-sz\Z  
} ZC}'! $r7  
catch(IOException e) cQ(zBf  
{ &)jBr^x#>  
e.printStackTrace (); 4q sIJJ[.  
} 48;6C g  
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return n; gc``z9@Xg
 
} `o~dQb/k+  
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} Py2AnpYa  
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 2fZVBj  
/* M-inlZNR  
**SiteInfoBean.java &+V6mH9m@  
*/ Z*&y8;vUQ  
package NetFox; n8W+q~sW%  
N-XOPwx'  
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public class SiteInfoBean { #oBMA  
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private String sSiteURL; //Site's URL VB 53n'  
private String sFilePath; //Saved File's Path h'*>\eC6  
private String sFileName; //Saved File's Name c@H_f  
private int nSplitter; //Count of Splited Downloading File ;',hwo_LBf  
{OFbU  
cp D=9k!*K  
public SiteInfoBean() 0($@9k4!/  
{//nSplitter的缺省值为5 [O)(0  
//default value of nSplitter is 5 g\9I&z~?  
this("","","",5); _dQVundH  
} f#4,2Xf  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Py^ _::  
{ k?(x}IZdG  
sSiteURL= sURL; Dn{ hU$*  
sFilePath = sPath; )qXl8HI  
sFileName = sName; ^{z
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this.nSplitter = nSpiltter; VI83 3  
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:r5DR`Rfm  
} <{$0mUn;s|  
0 #*M'C#  
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public String getSSiteURL() b.=bgRV2{x  
{ Fh2$,$ 2  
return sSiteURL; xd[GJ;xvs  
} e,j2#wjor  
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public void setSSiteURL(String value) ~W?F.  
{ UO3Q
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sSiteURL = value; +Fn^@/?yC  
} "9mVBa|Q  
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public String getSFilePath() kjCXP  
{ &)(>e}es  
return sFilePath; 2|="!c8K  
} 9 Vn  
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public void setSFilePath(String value) AH*{Bi[vX  
{ l,z# :k  
sFilePath = value; SZ/}2_;  
} P''5A6#5  
2oY.MQD7iW  
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public String getSFileName() <d2?A}<  
{ +TA'P$j  
return sFileName; \BIa:}9O  
} +w'"N  
x#wkODLqi  
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public void setSFileName(String value) b=V"$(Q  
{ ,7` /D  
sFileName = value; !Q-h#']~L  
} &ZkY9XO  
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public int getNSplitter() !v^{n+  
{ U<
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return nSplitter; )Dg;W6  
} oJ r&9.S  
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public void setNSplitter(int nCount) |I; tBqN{u  
{ />wM#)o2  
nSplitter = nCount; "6[a%f#Q  
} ejr9e@D^  
} CV9o,rL  
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/* ~&zrDj~FI  
**Utility.java 7(ni_|$|  
*/ [w0@7p"7
 
package NetFox; ,r=9$i_  
Iq76JJuCb  
hW^*b:v{  
public class Utility { 'hEvW  
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public Utility() DC&3=Nd  
{ pQQN8Y~^Y  
h
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|2i=oX(r|  
} wiwAdYEQ\  
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//线程睡眠 4trP*u,4  
public static void sleep(int nSecond) tHh
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{ s} I8:ufT  
try{ W0zRV9"P  
Thread.sleep(nSecond); pUGFQ."\  
} W6e,S[J^FY  
catch(Exception e) i~};5j(  
{ 8OS@gpz  
e.printStackTrace (); )[t zAaP7  
} lpjeEawo4  
} Ri<7!Y?l  
i6S5 4&^!  
//日志 n!Dr:$  
public static void log(String sMsg) \wJ2>Q  
{ u[{j;l(  
System.err.println(sMsg); ce3
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} fwkklg^  
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public static void log(int sMsg) #9(0.!v  
{ _1c0pQ^}3  
System.err.println(sMsg); n7|8`?R^  
} KF4D)NM|  
} e9LP!"@EY  
%>z4hH,  
%9q]  
/* F K7cDaI  
**TestMethod.java |)Q#U$ m  
*/ 6#J>b[Q  
package NetFox; yt5Sy  
s6DmZ^Y%  
*
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public class TestMethod { 1Fg*--8[r  
A^2n i=b  
|;(95  
public TestMethod() P&>!B,f  
{ ///xx/weblogic60b2_win.exe q&DM*!Jq  
try{ wV604eO(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N4[`pXM6
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !J6;F}Pd/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (&B`vgmb  
fileFetch.start(); zu,F 0;De  
}
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catch(Exception e){e.printStackTrace ();} 3)6TnY/u6{  
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} D2y[?RG  
#VvU8"u  
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public static void main(String[] args) wHR# -g'  
{ O)aWTI  
new TestMethod(); rA\6y6dFs  
} |zkZF|-  
} zao=}j?  
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