http断点续传简单实现（java)

/* 7"K^H]6u30  
**SiteFileFetch.java W_}/O'l{  
*/ 4U{m7[  
package NetFox; +*.1}r&  
import java.io.*; 0Cq!\nzz  
import java.net.*;
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public class SiteFileFetch extends Thread { -l[jEJS}  
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SiteInfoBean siteInfoBean = null; //文件信息Bean enumK\  
long[] nStartPos; //开始位置 |^iA6)Q  
long[] nEndPos; //结束位置 y\z > /q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 A{(T'/~"  
long nFileLength; //文件长度 41}/w3Z4  
boolean bFirst = true; //是否第一次取文件 DxfMqH[vs  
boolean bStop = false; //停止标志 ls @5^g  
File tmpFile; //文件下载的临时信息 Ay%:@j(E  
DataOutputStream output; //输出到文件的输出流 }p{;^B  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） yoU2AMH2D^  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1R^4C8*B  
{ @ef$b?wg  
siteInfoBean = bean; t:T?7-XIE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Nb1J ~v  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); oyW00]ka  
if(tmpFile.exists ()) &^+3errO  
{ u`6/I#q`  
bFirst = false;  i6 L  
read_nPos(); F`srE6H  
} |D<+X^0'  
else *l-`<.  
{ m^A]+G#/  
nStartPos = new long[bean.getNSplitter()]; )Mi'(C;  
nEndPos = new long[bean.getNSplitter()]; ` FxtLG,F  
} U`1l8'W}:#  
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} H"D5e  
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public void run() ?Pnx~m{%*  
{ fYn{QS?  
//获得文件长度 QS;F+cmTh  
//分割文件 B{PLIis
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//实例FileSplitterFetch 9P0yv3  
//启动FileSplitterFetch线程 Pgev)rh[  
//等待子线程返回 /RqhykgZ  
try{ l
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if(bFirst) #>bT<  
{ XHQh4W3  
nFileLength = getFileSize(); ppFYc\&=  
if(nFileLength == -1) n ,1tD  
{ 6(.H3bu
 
System.err.println("File Length is not known!"); 1J'pB;.]s  
} =qX*
]  
else if(nFileLength == -2) $',3Pv  
{ ^ $wJi9D6  
System.err.println("File is not access!");  "l2bx  
}
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else 2&x7W*  
{ oZ-FF'  
for(int i=0;i<nStartPos.length;i++) GA ik;R  
{ tN}
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); _>i|s|aW  
} T3rn+BxF7  
for(int i=0;i<nEndPos.length-1;i++) 6l[G1KkV  
{ @'HT;Q!\Vd  
nEndPos = nStartPos[i+1]; Y%h}U<y  
} |Ng"C`$oqv  
nEndPos[nEndPos.length-1] = nFileLength; 5m`[MBt2g  
} 6F-JK1i  
} J[r^T&o  
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//启动子线程 1MV
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !;+U_j'Pg  
for(int i=0;i<nStartPos.length;i++) (H1lqlVWV#  
{ ] R<FKJ[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2Y;!$0_rv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8nsZ+,@+[  
nStartPos,nEndPos,i); ]738Z/)^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3cHtf  
fileSplitterFetch.start(); uP Rl[tS0  
} /n8psj  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pg!`SxFD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1I \tu  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", yLB~P7K  
nEndPos = " + nFileLength); `oVB!eapl  
// fileSplitterFetch[nPos.length-1].start(); 48k7/w\  

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//等待子线程结束 f@x_#ov  
//int count = 0; \n;g2/VjO  
//是否结束while循环  mmcdtVe  
boolean breakWhile = false; _4!{IdR  
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while(!bStop) X(b1/lzA  
{ ig$jKou F  
write_nPos(); x5PP
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Utility.sleep(500); /6jGt'^U  
breakWhile = true; wibwyzo  
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for(int i=0;i<nStartPos.length;i++) "qgu$N4/>  
{ {NV:|M!  
if(!fileSplitterFetch.bDownOver) 9#fp_G;=  
{ f)U6p  
breakWhile = false; y<v|X2  
break; T g{UK  
} lvx]jd\  
} c>rKgx  
if(breakWhile) \kyM}5G(<0  
break; Vpw[B.v  
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//count++; {( dP  
//if(count>4) 44j,,
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// siteStop(); cafsMgrA  
} }U i_ynZ!  
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System.err.println("文件下载结束！"); '{CWanTPi  
} B#:E?a;{  
catch(Exception e){e.printStackTrace ();} L&'l3|  
} L:i+}F;M)s  
}b
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//获得文件长度 @sdS0pC  
public long getFileSize() 19) !$Hl  
{ R|-j]Ne  
int nFileLength = -1; V pH|R  
try{ dxntGH< O  
URL url = new URL(siteInfoBean.getSSiteURL()); EZ `}*Yrd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mV%h[~-  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]Ly8s#<g]N  
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int responseCode=httpConnection.getResponseCode(); QheDF7'z  
if(responseCode>=400) A'`P2Am  
{ a-:pJE.'p  
processErrorCode(responseCode); 716hpj#*  
return -2; //-2 represent access is error z 7@ 'CJ  
} q}e]*]dJZ  
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String sHeader; d{3I.$ThH  
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for(int i=1;;i++) Z>&K&ttJ  
{ 97(n\Wt2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); W%WC(/hor  
//Utility.log(in.readLine()); {>A
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sHeader=httpConnection.getHeaderFieldKey(i); k5C>_( A  
if(sHeader!=null) {<r`5  
{ G_0)oC@Jl:  
if(sHeader.equals("Content-Length")) `;e^2  
{ Q84t9b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;!:F#gahv  
break; rX:1_q`xA  
} x~nQm]@`h  
} n{3|E3  
else L*v93;|s  
break; \wFhTJY  
} C-&#r."L  
} K]9tc)  
catch(IOException e){e.printStackTrace ();} tbY SK  
catch(Exception e){e.printStackTrace ();} =:
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Utility.log(nFileLength); ZRUh/<\[  
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return nFileLength; AsD1-$  
} )#Y|ngZ_>  
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//保存下载信息（文件指针位置） @ E >eq.m  
private void write_nPos() 6z PV'~
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{ o;%n,S8J|^  
try{ unpfA#&!"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); YyG~#6aCh  
output.writeInt(nStartPos.length); ~ J%m  
for(int i=0;i<nStartPos.length;i++) A=W5W5l(>  
{ \ x:_*`fU  
// output.writeLong(nPos); Up'."w_zE  
output.writeLong(fileSplitterFetch.nStartPos); XQ4dohGCP  
output.writeLong(fileSplitterFetch.nEndPos); c_t7RWV}  
} 2=Jmi?k  
output.close(); 7f[8ED[4  
} z(#=tC|  
catch(IOException e){e.printStackTrace ();} aam1tm#Q  
catch(Exception e){e.printStackTrace ();} -}NAb^d  
} 8.PXTOhVL  
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//读取保存的下载信息（文件指针位置） k-io$  
private void read_nPos() O.dux5lfBd  
{ .\)--
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try{ ,b.kw}k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); r,QJG$ Jo  
int nCount = input.readInt(); #%;<FFu\  
nStartPos = new long[nCount]; Q.*'H_Y  
nEndPos = new long[nCount]; V2lp7"  
for(int i=0;i<nStartPos.length;i++) UP5%C;  
{ ^GrNfB[Qu  
nStartPos = input.readLong(); xu`d`!Tx  
nEndPos = input.readLong(); Vvxa.B  
} G#^m<G
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input.close(); anpJAB:1  
} 7=L:m7T  
catch(IOException e){e.printStackTrace ();} )H.ubM1  
catch(Exception e){e.printStackTrace ();} EUJ1RhajF  
} .QNjeMu.  
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private void processErrorCode(int nErrorCode) (/To?`  
{ wVlSjk  
System.err.println("Error Code : " + nErrorCode); O7!fI'R  
} =%:JjgKc*t  
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//停止文件下载 ](]*]a4ss  
public void siteStop() $:xF)E  
{ u XaL  
bStop = true; 3-4Nad  
for(int i=0;i<nStartPos.length;i++) Wdei`u[  
fileSplitterFetch.splitterStop(); iH($rSE  
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} rE!G,^_{  
} Y'3kE  
//负责部分文件的抓取 D!81(}p  
**FileSplitterFetch.java v$qpcu#o  
*/ !E4E'I=]N  
package NetFox; Nck!z8  
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import java.io.*; v=dKcruR:  
import java.net.*; e5]&1^+  
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public class FileSplitterFetch extends Thread { Z5"!0B^ j  
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String sURL; //File URL -='8_B/75  
long nStartPos; //File Snippet Start Position ~e,f)?  
long nEndPos; //File Snippet End Position >DSNKU+j  
int nThreadID; //Thread's ID ~gSF@tz@  
boolean bDownOver = false; //Downing is over &':UlzG  
boolean bStop = false; //Stop identical /zChdjz  
FileAccessI fileAccessI = null; //File Access interface 4SX3c:>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException o06A
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{ 'vqj5YTj  
this.sURL = sURL; 
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this.nStartPos = nStart; ?,A}E|jZ  
this.nEndPos = nEnd; I{i:B  
nThreadID = id; 
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 03i?"MvNo  
} 6Cop#kW#  
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public void run() +?4*,8Tmmz  
{ > Z.TM=qj  
while(nStartPos < nEndPos && !bStop) Eg287B  
{ ?NL&x  
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try{ <lg"M;&Ht  
URL url = new URL(sURL); aPcGI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {9m!UlTtw  
httpConnection.setRequestProperty("User-Agent","NetFox"); *il]$i  
String sProperty = "bytes="+nStartPos+"-"; 0ECO/EuCg  
httpConnection.setRequestProperty("RANGE",sProperty); n $D}0wSM/  
Utility.log(sProperty); 
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InputStream input = httpConnection.getInputStream(); 4iL.4Uj{N  
//logResponseHead(httpConnection); 7cOg(6N  
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byte[] b = new byte[1024];
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int nRead; ;%b <uV  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -.+KCt G$+  
{ Y]`lEq%  
nStartPos += fileAccessI.write(b,0,nRead); A~yw8v5UF  
//if(nThreadID == 1) : .FfE  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Kq@m?h  
} !h`cXY~w  
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Utility.log("Thread " + nThreadID + " is over!"); *`QdkVER  
bDownOver = true; ~L4*b*W  
//nPos = fileAccessI.write (b,0,nRead); Wq[=}qh~  
} 47(1V/
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catch(Exception e){e.printStackTrace ();} e&FX7dsyy  
} hM1&A  
} mZ& \3m=  
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//打印回应的头信息 R4Gg|Bh  
public void logResponseHead(HttpURLConnection con) #h #mOJ5  
{ #1,>Qnl  
for(int i=1;;i++) EP*["fx  
{ !4b;>y=m  
String header=con.getHeaderFieldKey(i); 7-G'8t  
if(header!=null) cfy/*|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5,=B1  
Utility.log(header+" : "+con.getHeaderField(header)); X&FuqB  
else aQym= 6%e  
break; bdsHA2r`s  
} Ilt L@]e  
} .T62aJ   
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public void splitterStop() }77=<N br  
{ `pv89aO  
bStop = true; kVG6\<c]  
} 9 FFfRIVY  
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} )2<B$p  
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/* i"\AyKiJ  
**FileAccess.java BF1O|Q|d6  
*//文件访问(定位，写) ,$zSJzS  
package NetFox; #G4~]Qml  
import java.io.*; Fh!!T%5>C  
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public class FileAccessI implements Serializable{ j O5:{%  
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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 `Hp.%G(  
RandomAccessFile oSavedFile; l)!woOt  
long nPos; ^hYR5SX  
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public FileAccessI() throws IOException ;P0Y6v3  
{ ?/|@ #&  
this("",0); Zy+QA>d|  
} g]PLW3  
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public FileAccessI(String sName,long nPos) throws IOException uB#B\i  
{ C$re$9U  
oSavedFile = new RandomAccessFile(sName,"rw"); >-@{vyoOy  
this.nPos = nPos; %OfDTs  
oSavedFile.seek(nPos); y\f8Ird  
} *a0I Z  
>"$-VY6i  
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public synchronized int write(byte[] b,int nStart,int nLen) PuoJw~^h  
{ .T$9Q Ar5  
int n = -1; !y2h`ZAZ  
try{ d`q)^  
oSavedFile.write(b,nStart,nLen); (!&O4C5  
n = nLen; XX5(/#  
} +n.j.JP"X  
catch(IOException e) 4[V6so0  
{ *d,n2a#n5  
e.printStackTrace (); hb8@br  
} K&P{2Hndr  
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return n; bHo?Rw!.  
} RKJWLofX&  
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} $O</akn;  
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/* yI)fu^  
**SiteInfoBean.java t T/*ZzMq#  
*/ 6;c{~$s~[  
package NetFox; YU\t+/b  
*[5#g3  
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public class SiteInfoBean { ={D
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private String sSiteURL; //Site's URL #?d>S;)+  
private String sFilePath; //Saved File's Path Ywb)h^{!  
private String sFileName; //Saved File's Name kC#B7*[RM  
private int nSplitter; //Count of Splited Downloading File Ex&RR< 5  
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public SiteInfoBean() Yiw^@T\H`  
{//nSplitter的缺省值为5 ~~E=E;9
  
//default value of nSplitter is 5 8; N
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this("","","",5); owVUL~  
} ] j?Fk$C  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e5\1k#@  
{ 
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sSiteURL= sURL; M@z/gy^  
sFilePath = sPath; Hx/Vm`pRyX  
sFileName = sName; l:C0:m%  
this.nSplitter = nSpiltter; J0)WRn"h  
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=,;3z/k%  
} `2~Ea_Z  
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public String getSSiteURL() H.S|njn:r  
{ w8@|b}  
return sSiteURL; 'eXw`kw(  
} u=i^F|  
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public void setSSiteURL(String value) 2/gj@>dt  
{ T`DlOi]Z_  
sSiteURL = value; ^?0,G>I
%-  
} F(n))`(  
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public String getSFilePath() ]6 7wk  
{ |,~A9  
return sFilePath; L}pF
b@
 
} PbH]K$mj{"  
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public void setSFilePath(String value) @wZ_VE7B  
{ sbhEZ#7#  
sFilePath = value; ^/YAokj  
} vu \Dx9  
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public String getSFileName() .Bn2;
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{ i-W2!;G  
return sFileName; $1 \!Oe[i  
} .F|WQ7Mu  
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public void setSFileName(String value) ]/naH#8G  
{ J}u1\Id%  
sFileName = value; \ku{-^7  
} kpUU'7Q  
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3"%44'  
public int getNSplitter() xeh|u"5  
{ PiQs><FK8  
return nSplitter; Nr+1N83S}  
} |*a>6y  
^%@.Vvz<  
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public void setNSplitter(int nCount) gJv^v`X  
{ {vlh,0~  
nSplitter = nCount; Oz7v hOU  
} 1 niTkop  
} #-,`4x$m|  
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/* RuuU}XQ  
**Utility.java wfzb:Aig`  
*/ ]<= t  
package NetFox; sVnuSm  
#nhAW  
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public class Utility { FeMu`|2  
(#Aq*2Z.  
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public Utility() /_(Dq8^g@  
{ '>$A7  
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} =@MKU  
?xs0J  
//线程睡眠 "YZ`g}sG  
public static void sleep(int nSecond) :gtwvM7/B  
{ R[t[M}q  
try{ ~ $&  
Thread.sleep(nSecond); =)bc/309  
} RwKN  
catch(Exception e) Q+dI,5YF  
{ R/|o?qTrj  
e.printStackTrace ();
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} `,"Jc<R7Z  
} 56dl;Z)  
oPir]`re  
//日志 w{IqzmPiH  
public static void log(String sMsg) -nSqB{s!SD  
{ >6q@Tr  
System.err.println(sMsg); j>23QPG`6U  
} KS_d5NvYl  
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w6 .HvH-@?  
public static void log(int sMsg) `rV,<  
{ |<$O5b'  
System.err.println(sMsg); kA0^~  
} Lf9h;z>#  
} +\Q@7Lj
 
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yvvR%]!.  
/* ER+[gT1CQ  
**TestMethod.java uy~j$lrn  
*/ v\C+G[MV7  
package NetFox; E{J
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public class TestMethod { ;7hr8?M|  
$Izk]o;X~  
_De;SB%V  
public TestMethod() hZy*E[i  
{ ///xx/weblogic60b2_win.exe 3t'K@W?AJh  
try{ 5KzU&!Zh9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); '%N p9Iqt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N1rrKyL!$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); COafVlJ,l  
fileFetch.start(); \D=B-dREq  
} [<hiOB  
catch(Exception e){e.printStackTrace ();} B7;MY6h#  
" B1' K8  
[cq>QMW  
} b3H;Ea?^^<  
DS yE   
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public static void main(String[] args) Y/gCtSF  
{ 2S3F]fG0  
new TestMethod(); B!0[LlF+  
} y\x<!_&D  
} Cpl)byb  
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