http断点续传简单实现（java)

/* ;>PV]0bOm>  
**SiteFileFetch.java 2-$R@ SVy  
*/ ]Y3ALQr!  
package NetFox; }Iu6]?|'  
import java.io.*; Va1|XQ<CL  
import java.net.*; _8bqk\m+  
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public class SiteFileFetch extends Thread { m8FKr/Z-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 77)C`]0(  
long[] nStartPos; //开始位置 $hA[vi\5  
long[] nEndPos; //结束位置 Qc6323/"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [P 8e=;  
long nFileLength; //文件长度 Sna7r~j  
boolean bFirst = true; //是否第一次取文件 2^|*M@3r  
boolean bStop = false; //停止标志 j3$KYf`T}  
File tmpFile; //文件下载的临时信息 f1Rm9
``  
DataOutputStream output; //输出到文件的输出流 RNm/&F1C$  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） jML}{>Gy8S  
public SiteFileFetch(SiteInfoBean bean) throws IOException -`rz[";n  
{ 6CCM7  
siteInfoBean = bean; I+}h+[W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); V;>p@uE,P  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `LNRl'Zm  
if(tmpFile.exists ()) 9X!OQxmg  
{ J H6\;G6  
bFirst = false; P,,@&* :  
read_nPos(); d=q2Or   
} eQMY3/#  
else W4Zi?@L>'  
{ c: _l+CgeH  
nStartPos = new long[bean.getNSplitter()]; p`Ax)L\f  
nEndPos = new long[bean.getNSplitter()]; `2GHB@S"k  
} SV-pS>#  
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} 1;SWfKU?.  
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public void run() tM~R?9OaJ  
{ ,*Sj7qb#  
//获得文件长度 y+@7k3"  
//分割文件
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//实例FileSplitterFetch S?;&vs9j  
//启动FileSplitterFetch线程 9^ )=N=wV  
//等待子线程返回 #p0vrQ;5f  
try{ I:[3x2H  
if(bFirst) {G_ZEo#x8,  
{ ) _"`
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nFileLength = getFileSize(); \ VJ3  
if(nFileLength == -1) Rs7=v2>I  
{ &d=j_9   
System.err.println("File Length is not known!"); YMC*<wXN  
} |]^OX$d  
else if(nFileLength == -2) 4h?[NOA"  
{ 9=Y-w s  
System.err.println("File is not access!"); EZa
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} .#P'NF(5#  
else *uNa(yd  
{ S$ dFz  
for(int i=0;i<nStartPos.length;i++) Q!MS_ #O  
{ YS%HZFY, "  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _r&`[@m  
} v 6Tz7  
for(int i=0;i<nEndPos.length-1;i++) !\2Xr{f  
{ tyNT1F{  
nEndPos = nStartPos[i+1]; ~`(#sjr6KR  
} ,SH))%Cyt  
nEndPos[nEndPos.length-1] = nFileLength; c:M~!CXO  
} Beqzw0  
} G-xW&wC-  
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//启动子线程 k#&d`?X  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )mS Aog<  
for(int i=0;i<nStartPos.length;i++) gm\P`~+o  
{ >`SIB; &>j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "I}3*s9Q-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {+!m]-s  
nStartPos,nEndPos,i); *CMe:a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~+7q.XL$$K  
fileSplitterFetch.start(); .9PPWY;H  
} 5_9mA4gs@  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^,qi`Tk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7NE"+EP\{2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Rra<MOR  
nEndPos = " + nFileLength); 
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// fileSplitterFetch[nPos.length-1].start(); UW_fn  
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>S,yqKp37~  
//等待子线程结束 Z`Rrv$M!  
//int count = 0; *shE-w;C  
//是否结束while循环 F$F,I,$ "  
boolean breakWhile = false; |gg6|,Bt4  
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while(!bStop) ozy~`$;c  
{ Y92wL}  
write_nPos(); h(l4\)  
Utility.sleep(500);
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breakWhile = true; w9Bbvr6  
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for(int i=0;i<nStartPos.length;i++) a<*q+a(*W  
{ '@i0~  
if(!fileSplitterFetch.bDownOver) T
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{ rozp  
breakWhile = false; m-Z<zEQ  
break; 4i|yEf  
} LVP2jTz  
} 4+"2K-]   
if(breakWhile) wc`UcGO  
break; nLicog)!I  
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//count++; Y@B0.5U2  
//if(count>4) R~ n[g  
// siteStop(); P'MfuTtT&  
} )_BQ@5NK  
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System.err.println("文件下载结束！"); j
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} jMr[U
Z  
catch(Exception e){e.printStackTrace ();} |C"(K-do  
} =z#6mSx|W  
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//获得文件长度 tqbYrF)  
public long getFileSize() -|V
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{ ZEa31[@B[  
int nFileLength = -1; @ >_v/U'  
try{ p?rh+0wgX  
URL url = new URL(siteInfoBean.getSSiteURL()); |iSd
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z$jqB~=^e  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]t0]fb[J  
o?5m^S14[1  
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int responseCode=httpConnection.getResponseCode(); {02$pO  
if(responseCode>=400) c[VVCN8dA  
{ ;\a?xtIy  
processErrorCode(responseCode); ,Y9bXC8+dU  
return -2; //-2 represent access is error ~P!\;S  
} w]1hoYuV  
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String sHeader; hvW FzT5  
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for(int i=1;;i++) Ck1{\=t  
{ iepolO=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); k0r93xa  
//Utility.log(in.readLine()); wH]5VltUT1  
sHeader=httpConnection.getHeaderFieldKey(i); Z?JR6;@W  
if(sHeader!=null) "xWrYq'"  
{ !U::kr=t  
if(sHeader.equals("Content-Length")) y[`>,?ns5  
{ gug9cmA/Q7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _\&vA5-  
break; Mbm'cM&}  
} !#&`1cYX  
} t?Ku6Z'  
else Dxvizd>VU  
break; 1FA:"0lO  
} (}B3df  
} E)>.2{]C>  
catch(IOException e){e.printStackTrace ();} okm }%#|  
catch(Exception e){e.printStackTrace ();} O}s Mqh  
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Utility.log(nFileLength); VEsIhjQ  
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return nFileLength; !}lCwV  
} )B*D\9\Z  
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//保存下载信息（文件指针位置） qt{l
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private void write_nPos() )WNw0cV}J>  
{ M"\Iw'5$  
try{ {"PIS&]tR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %fuV
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output.writeInt(nStartPos.length); 3QI.|;X  
for(int i=0;i<nStartPos.length;i++) Llf#g#T  
{ 'nIKkQ" N  
// output.writeLong(nPos); jhR`%a
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output.writeLong(fileSplitterFetch.nStartPos); >\?RYy,s$  
output.writeLong(fileSplitterFetch.nEndPos); \X2
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} icK>
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output.close(); Uee(1  
} s3-TBhAv  
catch(IOException e){e.printStackTrace ();} tp<v  
catch(Exception e){e.printStackTrace ();} K>2M*bGcp  
} -bd'sv  
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//读取保存的下载信息（文件指针位置） ni$;"RGC  
private void read_nPos() "|Gr3sD  
{ mWUkkR(/  
try{ prEI9/d"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;,lFocGv  
int nCount = input.readInt(); Y{d-k1?s5  
nStartPos = new long[nCount]; J ?0P{{  
nEndPos = new long[nCount]; tdsfCvF=a  
for(int i=0;i<nStartPos.length;i++) "IHFme@^  
{ H-,p.$3}  
nStartPos = input.readLong(); xs6kr  
nEndPos = input.readLong(); CzDV^Iv;Q{  
} ;&dMtYb  
input.close(); b+`qGJrej  
} yGY:EvH^?  
catch(IOException e){e.printStackTrace ();} V]Rt[l]  
catch(Exception e){e.printStackTrace ();}
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} 0Ke2%+yqJ  
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private void processErrorCode(int nErrorCode) g43(N!@g  
{ &gF9VY  
System.err.println("Error Code : " + nErrorCode); [
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} :85QwN]\  
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//停止文件下载 !bIE%cq  
public void siteStop() B[IWgvB(e  
{ 5?Ukf$)x  
bStop = true; a9u2Wlz  
for(int i=0;i<nStartPos.length;i++)  RnSll-  
fileSplitterFetch.splitterStop(); bkuJN%  
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} bcgXpP  
} -TMg9M4  
//负责部分文件的抓取 ]D&U}n  
**FileSplitterFetch.java Dz&,g+>$J  
*/ "TI>_~  
package NetFox; %'u
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import java.io.*; ||L^yI~_d  
import java.net.*; &5[B\yv  
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public class FileSplitterFetch extends Thread { OZ33w-X<  
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String sURL; //File URL 0|<9eD\I=  
long nStartPos; //File Snippet Start Position vb| d  
long nEndPos; //File Snippet End Position b<%c ]z  
int nThreadID; //Thread's ID Wecxx^vtv6  
boolean bDownOver = false; //Downing is over S5kD|kJ  
boolean bStop = false; //Stop identical lMl'+ yy  
FileAccessI fileAccessI = null; //File Access interface "G^TA:O:=  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nu)YN1 *  
{ 6L;]5)#
 
this.sURL = sURL; *aJO5&w<T  
this.nStartPos = nStart;  |e<$  
this.nEndPos = nEnd; 9 p,O>I  
nThreadID = id; T^F83Py<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;b(ww{&  
} (*b<IGi;  
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public void run() P4zwTEk`  
{ ^f57qc3nF  
while(nStartPos < nEndPos && !bStop) [mQdc?n\  
{ Y/5(BK)  
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try{ IT7],pM  
URL url = new URL(sURL); peHjKK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i&8|@CACb  
httpConnection.setRequestProperty("User-Agent","NetFox"); FQ>kTm`d
 
String sProperty = "bytes="+nStartPos+"-"; ~<-mxOe  
httpConnection.setRequestProperty("RANGE",sProperty); =~"X/>'  
Utility.log(sProperty); bT6VxbNS  
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InputStream input = httpConnection.getInputStream(); 6{{<+ o  
//logResponseHead(httpConnection); {kBsiSvsA;  
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byte[] b = new byte[1024]; t\h4-dJn  
int nRead; jABFdNjri  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) SME9hS$4  
{ AusjN-IL  
nStartPos += fileAccessI.write(b,0,nRead); N:CQ$7T{ j  
//if(nThreadID == 1) 93Zij<bH?e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =@pD>h/~  
} sgDSl@lB  
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Utility.log("Thread " + nThreadID + " is over!"); icX4n  
bDownOver = true; MV
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//nPos = fileAccessI.write (b,0,nRead); ~o/k?l  
} jO/cdLKX(  
catch(Exception e){e.printStackTrace ();} Faa>bc~E  
} {6WG  
} Zk/ejhy0  
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//打印回应的头信息 t|V<K^  
public void logResponseHead(HttpURLConnection con) &AOGg\  
{ :8]8
[  
for(int i=1;;i++) }*U|^$FEU  
{ YU"/p|!1  
String header=con.getHeaderFieldKey(i); I 44]W&  
if(header!=null) i]N<xcF9N*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); w@&z0ODJ  
Utility.log(header+" : "+con.getHeaderField(header)); I`*5z;Q!%@  
else S0Io$\ha  
break; wP*3Hx;S  
} o&&`_"18  
} Kc95yt  
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public void splitterStop() nGe4IY\-w  
{ (# mvDz  
bStop = true; E N%{ $  
} ;Ce?f=4  

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} ;ne`ppz0  
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/* 4].o:d;`/  
**FileAccess.java 6dmb bgO)  
*//文件访问(定位，写) b_ak@LYiu  
package NetFox; 6r`N\ :18  
import java.io.*; FZn1$_Svr  
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public class FileAccessI implements Serializable{ 1U#W=Fg'  
$ZGup"z)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `kxC# &HO  
RandomAccessFile oSavedFile; l?2  
long nPos; i+qg
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public FileAccessI() throws IOException Exqz$'(W9  
{ 7%EIn9P  
this("",0); wM4{\  f\  
} qqe"hruF
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public FileAccessI(String sName,long nPos) throws IOException _AFje  
{ = g &  
oSavedFile = new RandomAccessFile(sName,"rw"); xT_"` @  
this.nPos = nPos; |" WL  
oSavedFile.seek(nPos); S9P({iZK  
} oJ %Nt&q  
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public synchronized int write(byte[] b,int nStart,int nLen) qb
sod  
{ |9%~z0  
int n = -1; O5vfcX4>  
try{ bR)P-9rs  
oSavedFile.write(b,nStart,nLen); u&1M(~Ub=  
n = nLen; i8k} B o  
} fMFkA(Of^  
catch(IOException e) &"JC
8  
{ ^7/v[J<<  
e.printStackTrace (); S+~;PmN9qL  
} x%r$/=  
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;
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return n; .pWRV<25  
} b#p0s?*  
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} NZv8#  
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/* APF`b  
**SiteInfoBean.java C_/eNu\I  
*/ r<1W.xd":  
package NetFox; #*.4Jv<R  
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public class SiteInfoBean { ;"Qq/knVL  
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private String sSiteURL; //Site's URL SF*mY=1  
private String sFilePath; //Saved File's Path KTT
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private String sFileName; //Saved File's Name BM:p)%Pv#P  
private int nSplitter; //Count of Splited Downloading File Y\_mqd  
l![79eFp  
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public SiteInfoBean() yN{**?b  
{//nSplitter的缺省值为5 )e PQxx  
//default value of nSplitter is 5 w9GY/]  
this("","","",5); @H$am  
} 5)S;R,  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) D9NRM;v  
{ +qjZ;5(  
sSiteURL= sURL; *!"T^4DEg  
sFilePath = sPath; > `eo0  
sFileName = sName; faLfdUimJ  
this.nSplitter = nSpiltter; Q+K]:c  
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} ~h8k4eM  
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public String getSSiteURL() C$])q`9  
{ (AZneK :*  
return sSiteURL; ld(_+<e  
} / zNVJhC  
:/=P6b;  
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public void setSSiteURL(String value) $<Gt^3e  
{ 4%nK0FAj  
sSiteURL = value; wjX0r7^@  
} h6LjReNo  
t"%~r3{  
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public String getSFilePath() otjT?R2g'  
{ ^8oN~HLZ  
return sFilePath; d:&cq8^  
} AX@bM  
\ :@!rM  
Y(rQ032s  
public void setSFilePath(String value) (0 t{  
{ Dy. |bUB!f  
sFilePath = value; E"BW-<_!  
} S?v;+3TG  
kH0kf-4\  

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public String getSFileName() 2i6P<&@  
{ aF"PB h=  
return sFileName; ]nIVP  
} f~=e  
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public void setSFileName(String value) Aj\m57e,6  
{ >/GYw"KK  
sFileName = value; mrE>o!  
} uKIR$n"  
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public int getNSplitter() 
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{ cru&nH*O^  
return nSplitter; GF<SQHL,  
} w"Zws[pm]  
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public void setNSplitter(int nCount) S,+|A)\#  
{ !C' Y 7  
nSplitter = nCount; Gqar5  
} "$%&C%t  
} 6 ;\>,  
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/* W-RshZ\  
**Utility.java ) { "}b
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*/ +Sv2'& B  
package NetFox; Sf`?j  
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public class Utility { r)qow.+&  
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public Utility() }`$({\^w  
{ XH
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} GV)DLHiyxX  
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//线程睡眠 c&L|e$C]  
public static void sleep(int nSecond) G"<} s mB  
{ W6*5e{  
try{ kf",/?s2Z  
Thread.sleep(nSecond); H8qAj  
} =p!Hl#  
catch(Exception e) 5&U?\YNLa  
{ $>l65)(E\  
e.printStackTrace (); <M
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} 1NlpOVq:)  
} ^''3}<Ep  
60p*4>^v  
//日志 zZCssn;[  
public static void log(String sMsg) l(tMo7iPa  
{ DoJ3zYEk  
System.err.println(sMsg); XlxB%  
} QfU{W@!h  
h4M>k{  
0s%{m<  
public static void log(int sMsg) 2mvp|<"  
{ /(ArA=#  
System.err.println(sMsg); _H2%6t/V  
} 9[\$\l  
} 'F8:|g  
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/* qZ+^ND(I  
**TestMethod.java oJ}$ /_  
*/ /u'
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package NetFox; b;(BMO,(  
y"0!7^  
!='&#@7u  
public class TestMethod { klC48l  
+Xr87x;  
nR$Q~`  
public TestMethod() 5./(n7d_  
{ ///xx/weblogic60b2_win.exe Nj4^G ~_  
try{ PHn3f;I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); o{ \r1<D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _/[(&}M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w8AHs/'r  
fileFetch.start(); F1zsGlObu}  
} e~BUAz  
catch(Exception e){e.printStackTrace ();} 8 =<&9TmE  
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} '^6x-aeq[D  
#v4q:&yKf  
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public static void main(String[] args) -jsk-,  
{ m3K .\3  
new TestMethod(); 6/thhP3`-  
} 3LD`Ep   
} 6oLq2Z8uP  
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