http断点续传简单实现（java)

/* #,GpZ  
**SiteFileFetch.java kOJs;k  
*/ [UFLL:_sC  
package NetFox; fMhMB |W.  
import java.io.*; J6
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import java.net.*; `MEH/  
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public class SiteFileFetch extends Thread { 1Te:&d  
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SiteInfoBean siteInfoBean = null; //文件信息Bean X}g!
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long[] nStartPos; //开始位置 a i}8+L8-  
long[] nEndPos; //结束位置 !3d+"tL S  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a o\+%s  
long nFileLength; //文件长度 Qm ;ip E  
boolean bFirst = true; //是否第一次取文件 iB[%5i-  
boolean bStop = false; //停止标志 |>VDMezy  
File tmpFile; //文件下载的临时信息 HR)joD*q;[  
DataOutputStream output; //输出到文件的输出流 ;h] zN  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =V%s^  
public SiteFileFetch(SiteInfoBean bean) throws IOException .:$%3#N$(Y  
{ u["Pg  
siteInfoBean = bean; O@?? NF6G  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -1Tws|4gc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); P ,5P6Y9  
if(tmpFile.exists ()) S'2
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{ jC<<S  
bFirst = false; glPOW  
read_nPos(); ym
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} mu|#(u  
else G#n27y nh  
{ |o=eS&)  
nStartPos = new long[bean.getNSplitter()]; W=]QTx,J  
nEndPos = new long[bean.getNSplitter()]; G^j/8e  
}  cfpP?  
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} D|6prC%/  
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public void run() )7O4j}B){  
{ *\:u}'[  
//获得文件长度 7S1 Y)  
//分割文件 9cX ~
 
//实例FileSplitterFetch 0|P RCq  
//启动FileSplitterFetch线程 ,Q >u N  
//等待子线程返回 zVJwmp^  
try{ 5\RKT)%X  
if(bFirst) SJj0*ry:  
{ )O2giVq7[0  
nFileLength = getFileSize(); CzST~*lH  
if(nFileLength == -1) 3[aCy4O  
{ fg+Q7'*Vq  
System.err.println("File Length is not known!"); Z!7#"wO9+V  
} jA<v<oV  
else if(nFileLength == -2) ZrXvR`bsw  
{ Ah)_mxK  
System.err.println("File is not access!"); [6)`wi  
} vR-rCve$P  
else l 0jjLqm:  
{ xgnt)&7T  
for(int i=0;i<nStartPos.length;i++) #Ubzh`v  
{ vgo-[^FiP$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Gb~*[  
} _`*x}  
for(int i=0;i<nEndPos.length-1;i++) 97NF*-)N  
{ uZ\ >  
nEndPos = nStartPos[i+1]; N>'1<i?  
} \0'o*nlJ  
nEndPos[nEndPos.length-1] = nFileLength; fQ'P2$  
} #V*<G#B  
} TZ?va@2  
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//启动子线程 fG2\p&z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; N1zB;-0t  
for(int i=0;i<nStartPos.length;i++) 8yA:C  
{ Tg)Fr)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fA2H8"r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wT3QSJ  
nStartPos,nEndPos,i); P%g[!9 '  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f
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fileSplitterFetch.start(); &tkkn2t  
} U}_l]gNn  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +#A>[,U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); j'#W)dp(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", CKmoC0.  
nEndPos = " + nFileLength); MjQKcL4%7  
// fileSplitterFetch[nPos.length-1].start(); I[WW1P5  
B/c_pRl;  
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//等待子线程结束 7Ha +@  
//int count = 0; [XhuJdr"u  
//是否结束while循环 .~4%TsBaY  
boolean breakWhile = false; wJ/k\  
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while(!bStop) u&9|9+"N  
{ HhH[pE  
write_nPos(); cRDjpc]  
Utility.sleep(500); 5E+l5M*(  
breakWhile = true; c<r`E  
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for(int i=0;i<nStartPos.length;i++) B=JeZMn  
{ #3f\,4K5  
if(!fileSplitterFetch.bDownOver) \\Fl,'  
{ Z; r}Gm  
breakWhile = false; GCkc[]2p  
break; 'dDd9  
} ~^UQw?;  
} O\q|b#q}/  
if(breakWhile) p>96>7w  
break; ac p-4g+j  
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//count++; ahU\(=  
//if(count>4) B!jT@b{  
// siteStop(); .zAB)rNc |  
} EXK~Zf|&Z  
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System.err.println("文件下载结束！"); <2HI. @^  
} q UY;CEf  
catch(Exception e){e.printStackTrace ();} 4xjk^N9  
} =iB0ak  
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//获得文件长度 Klzsr,  
public long getFileSize() XwOj`N{!H  
{ o6P)IZ1  
int nFileLength = -1; rgWGe6;!  
try{ CD:@OI  
URL url = new URL(siteInfoBean.getSSiteURL()); J0~Ha u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Qb!9QlW  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^PMP2\JQA  
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int responseCode=httpConnection.getResponseCode(); {*bXO8vi((  
if(responseCode>=400) 7[[XNJP  
{ EX7gTf#  
processErrorCode(responseCode); -\:pbR
  
return -2; //-2 represent access is error \SkCsE#H  
} 6=3}gd5  
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String sHeader; f>g>7OsD]  
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for(int i=1;;i++) Y.Na9&-(  
{ n{J<7I e"*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); '-p<E"#4Z  
//Utility.log(in.readLine()); ]O3[Te  
sHeader=httpConnection.getHeaderFieldKey(i); yk5-@qo  
if(sHeader!=null) X!2/cgU7  
{ U-6b><  
if(sHeader.equals("Content-Length")) =P\H}?PF  
{ 0%7c?3#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $&M"Ji  
break; A_6b 4T  
} d nWh}!  
} c!AGKc  
else q%i2'yE  
break; `PnB<rf:*1  
} ~Aq;g$IJZ  
} ):E4qlB  
catch(IOException e){e.printStackTrace ();} #>g]CRN  
catch(Exception e){e.printStackTrace ();} Dtl381F J  
}A'QXtI/G  
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Utility.log(nFileLength); ,kfUlv
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return nFileLength; a*o#,T5A  
} }@_F( B  
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//保存下载信息（文件指针位置） nyD(G=Q5  
private void write_nPos() BY.'0,H=k  
{ NdZv*  
try{ T52A}vf4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @
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output.writeInt(nStartPos.length); @x3x/gU  
for(int i=0;i<nStartPos.length;i++) % zHsh  
{ -bd
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// output.writeLong(nPos); WBL
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output.writeLong(fileSplitterFetch.nStartPos); xw(KSPN  
output.writeLong(fileSplitterFetch.nEndPos); SE&J)Sj]  
} RNE})B  
output.close(); kaQn'5  
} m!L&_Z|j  
catch(IOException e){e.printStackTrace ();} 8*V^DM3n-  
catch(Exception e){e.printStackTrace ();} Jf{
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} }A;J-7g6  
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//读取保存的下载信息（文件指针位置） \2~Cn c*O  
private void read_nPos() P#-Ye<V~J(  
{ d#cw`h<c~  
try{ q|0Lu  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2uu"0Rm%  
int nCount = input.readInt(); %:yJ/&-Q,Z  
nStartPos = new long[nCount]; NitWIj[
U;  
nEndPos = new long[nCount]; :KGUO{_u  
for(int i=0;i<nStartPos.length;i++) T|`nw_0  
{ uA dgR  
nStartPos = input.readLong(); fT9$0:eO  
nEndPos = input.readLong(); 422d4Zu  
} /co^swz  
input.close(); CKeT%3  
} gF,9Kv~  
catch(IOException e){e.printStackTrace ();} Xn^gxOPM  
catch(Exception e){e.printStackTrace ();} |fkz=*rn  
} eS{lr4-]  
. S4Xw2MS  
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private void processErrorCode(int nErrorCode) MX2Zm  
{ //S/pCqED  
System.err.println("Error Code : " + nErrorCode); =Bu>}$BD  
} BWV)> -V  
|{]W (/  
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//停止文件下载 U<QO@5  
public void siteStop() U0G(  
{ 6OuB}*  
bStop = true; E-\Wo3  
for(int i=0;i<nStartPos.length;i++) ]E$h7I  
fileSplitterFetch.splitterStop(); kBg,U8|S  
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} VgLrufJ  
} &6V[@gmD  
//负责部分文件的抓取 <XG&f
  
**FileSplitterFetch.java xwoK#eC~F  
*/ +Z99x#  
package NetFox; da<B6!  
@."_XL74  
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import java.io.*; {2QCdj46  
import java.net.*; %>u(UmFO  
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public class FileSplitterFetch extends Thread { Hz39
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String sURL; //File URL =E?kxf[X  
long nStartPos; //File Snippet Start Position ~~,] b  
long nEndPos; //File Snippet End Position (Ubz@s^  
int nThreadID; //Thread's ID ^ z!g3  
boolean bDownOver = false; //Downing is over D>neY9  
boolean bStop = false; //Stop identical SbS*z:  
FileAccessI fileAccessI = null; //File Access interface V
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tP/0_^m  
{ b?S,%  
this.sURL = sURL; *l\wl @{  
this.nStartPos = nStart; p,#t[K  
this.nEndPos = nEnd; ypyqf55gK  
nThreadID = id; 3[`/rg,  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Yl}'hRp  
} mN+ w,  
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public void run() zpi Q;P  
{ x -CTMKX  
while(nStartPos < nEndPos && !bStop) fL-lx-~  
{ pK/r{/>r  
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try{ NL`}rj  
URL url = new URL(sURL); 8x":7 yV&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E
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httpConnection.setRequestProperty("User-Agent","NetFox"); i"
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String sProperty = "bytes="+nStartPos+"-"; !' ;1;k);  
httpConnection.setRequestProperty("RANGE",sProperty); ob=](  
Utility.log(sProperty); FO[x
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InputStream input = httpConnection.getInputStream(); rBY)rUDd4  
//logResponseHead(httpConnection); MPaF  
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byte[] b = new byte[1024]; i{T mn  
int nRead; 1{%3OG^'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) I$yFCdXr  
{ LTsX{z  
nStartPos += fileAccessI.write(b,0,nRead); aYy+iP'$  
//if(nThreadID == 1) ~1xfE C/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8rZJvE#c  
} y^OT0mZkg  
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| R\PQ/)  
Utility.log("Thread " + nThreadID + " is over!"); mV~aZM0'  
bDownOver = true; }J_"/bB  
//nPos = fileAccessI.write (b,0,nRead); 4th*=ku  
} .5?e)o)  
catch(Exception e){e.printStackTrace ();} R*S9[fqC[  
} "INIP?  
} 'BUix!k0<  
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//打印回应的头信息 TPE1}8p17  
public void logResponseHead(HttpURLConnection con) R_JB`HFy=  
{ VK)vb.:  
for(int i=1;;i++) R%%Uw %`  
{ <vb%i0+b.^  
String header=con.getHeaderFieldKey(i); &7-ENg9 [  
if(header!=null) A[7\!bq5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); w; rQ\gj  
Utility.log(header+" : "+con.getHeaderField(header)); &|]GTN`E  
else m/E$0tf  
break; 9-B/n0  
} e^
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} FqWW[Bgd  
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public void splitterStop() u)X]]6
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{ :ebu8H9f%  
bStop = true; =\ek;d0Tqb  
} Xh5&J9pw   
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} dQ.:xu}~  
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/* GZq~Pl  
**FileAccess.java -f&m4J} E  
*//文件访问(定位，写) A )q=.C#e  
package NetFox; f)_k_<  
import java.io.*; g6D7Y<}d  
l b9O  
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public class FileAccessI implements Serializable{ L\cbY6b  
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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 \Bvy~UeE)>  
RandomAccessFile oSavedFile; /z)H
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long nPos; r9 5hW  
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public FileAccessI() throws IOException S Boi|  
{ 0F5QAR O  
this("",0); a#pM9n~a  
} -J& b~t@  
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public FileAccessI(String sName,long nPos) throws IOException )x<oRHx]  
{ )k~{p;Ke  
oSavedFile = new RandomAccessFile(sName,"rw"); 1m{c8Z.h/d  
this.nPos = nPos; dq4t@:\o0  
oSavedFile.seek(nPos); O>c2*9PM  
} SB)Hz8<  
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public synchronized int write(byte[] b,int nStart,int nLen) Io*mFa?  
{ b/]@G05>>  
int n = -1; O<\h_   
try{ Ly~s84k_po  
oSavedFile.write(b,nStart,nLen); cT.8&EEW  
n = nLen; IxU#x*  
} L?&Trq7i  
catch(IOException e) Z,QSbw@,7  
{ %;ZDw@_<  
e.printStackTrace (); gyT3[*eh  
} lHc|:vG?  
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return n; ']^
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} .t9*wz  
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} _08y; _S  
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/* k%K\~U8"  
**SiteInfoBean.java UNhM:!A  
*/ # n\|Q\W  
package NetFox; )uK Tf=;  
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public class SiteInfoBean { q +*>T=k  
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private String sSiteURL; //Site's URL (jtkY_  
private String sFilePath; //Saved File's Path Dy|DQ>?}  
private String sFileName; //Saved File's Name Q39;bz
  
private int nSplitter; //Count of Splited Downloading File w<me(!-'  
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public SiteInfoBean() gMB/ ~g5b0  
{//nSplitter的缺省值为5 PESJ7/
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//default value of nSplitter is 5 G&\!!i|IQ  
this("","","",5); qYbPF|Y=Z  
} <xaB$}R  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) f'&   
{ lFc4| _c g  
sSiteURL= sURL; z\6/?5D#
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sFilePath = sPath; L.$+W}  
sFileName = sName; kT,2eel  
this.nSplitter = nSpiltter; 1g1gu=|Q  
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} |X0Ys8f  
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public String getSSiteURL() .9u,54t  
{ fudLm  
return sSiteURL; hZDv5]V:0  
} O/{W:hJjd  
~\~XD+jy"  
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public void setSSiteURL(String value) d
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{ L}.V`v{zc  
sSiteURL = value; :taRCh5  
} ~8^)[n+)x  
* ~4m!U_s  
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public String getSFilePath() Rss=ihlM  
{  !#Hca  
return sFilePath; oQ_n
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} cwKOE?!  
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J6*B=PX=(  
public void setSFilePath(String value) Ykt(%2L  
{ <B=!ZC=n  
sFilePath = value; ey3;rY1  
} "Qxn}$6-  
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public String getSFileName() ^><B5A>;  
{ >6cENe_@t  
return sFileName; H=k`7YN  
} $[-{Mm  
C
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public void setSFileName(String value) "yV)&4)  
{ $N`uM  
sFileName = value; ?FRQ!R  
} fl18x;^I  
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public int getNSplitter() !WReThq  
{ ^Wz3 q-^  
return nSplitter; u:7=Yy :  
} _ Oe|ZQ  
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*tZ#^YG{(  
public void setNSplitter(int nCount) G$HLta  
{ ,*$/2nB^  
nSplitter = nCount; tXIre-. 2}  
} Oz1ou[8k  
} b1{XGK'  
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/* sP NAG  
**Utility.java I#tEDeF2  
*/ aE2 3[So  
package NetFox; ]\:FFg_O6t  
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public class Utility { tKUy&]T  
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public Utility() N#`aVW'{v2  
{ .iL_3:6f  
7" wn024  
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} 7#R& OQ  
S-:7P.#Q  
//线程睡眠 7TQh'j  
public static void sleep(int nSecond) [+st?;"GF  
{ =9;jVaEMJL  
try{ 9h6
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Thread.sleep(nSecond); IK6XJsz$J  
} 4l?98  
catch(Exception e) _u:4y4}  
{ 3&@MZF&  
e.printStackTrace (); s `r tr  
} OQA3~\Vu  
} 6]}Xi:I
 
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//日志 =;3|?J0=  
public static void log(String sMsg) CFh&z^]PR  
{ u0J+Nj9  
System.err.println(sMsg); o/fq  
} *X;g Y  
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public static void log(int sMsg) wz!]]EQ!o  
{ 4[!&L:tR  
System.err.println(sMsg); 7,e=|%7.  
} `q exEk@S  
} Ac.z6]p  
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uBks#Y*3$  
/* ^tuJM:  
**TestMethod.java AN
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*/ %;zWS/JhL  
package NetFox; 7q|(ZZa  
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public class TestMethod { "7)F";_(^  
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public TestMethod() _V{WXsOx(  
{ ///xx/weblogic60b2_win.exe =dX*:An  
try{ /:e|B;P`k  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?XGZp?6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %p2C5z?  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  aG\m3r  
fileFetch.start(); va;d[D,  
} `>8|  
catch(Exception e){e.printStackTrace ();} n37( sKG  
kozg8 `\]  
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} M14_w,  
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public static void main(String[] args) ^B& Z  
{ U)p2PTfB  
new TestMethod(); B>Nx
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} oT|E\wj  
} z<<` 1wqg  
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