http断点续传简单实现（java)

/* ")Fd'&58  
**SiteFileFetch.java ]Z!Y*v  
*/ C >*z^6Gz  
package NetFox; YdI6|o@vc  
import java.io.*;  V FM[-  
import java.net.*; SlsNtaNt  
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public class SiteFileFetch extends Thread { ir^d7CV,  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :lu!%p<$  
long[] nStartPos; //开始位置 O!Ue0\1Kj0  
long[] nEndPos; //结束位置 m]DP{-s4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 % 3#g-  
long nFileLength; //文件长度 Q}&'1J  
boolean bFirst = true; //是否第一次取文件 rbf5~sw&8+  
boolean bStop = false; //停止标志 6Emn@Mn=  
File tmpFile; //文件下载的临时信息 " lD -*e4  
DataOutputStream output; //输出到文件的输出流 rT="ciQ  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &Hw:65O  
public SiteFileFetch(SiteInfoBean bean) throws IOException |mhKD#:  
{ `
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siteInfoBean = bean; [CHN3&l-5S  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y95 #t  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /8Lb_QH{  
if(tmpFile.exists ()) B)k/]vz)*D  
{ v0'z''KM!  
bFirst = false; 0Y`+L6&UX  
read_nPos(); z7fX!'3V  
} F]OWqUV  
else IlEU6Rs  
{ K81FKV.  
nStartPos = new long[bean.getNSplitter()]; li3X}
  
nEndPos = new long[bean.getNSplitter()]; 41R~.?  
} K*~xy bA  
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} ca &zYXy  
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public void run() E:}s6l  
{ J;fbE8x  
//获得文件长度 uT
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//分割文件 <a CzB7x  
//实例FileSplitterFetch 7\dt<VV  
//启动FileSplitterFetch线程 g9GPyU  
//等待子线程返回 6\h*SBI?(  
try{ p+I`xyk  
if(bFirst) m[ S1  
{  w&U28"i>  
nFileLength = getFileSize(); af'ncZ@U  
if(nFileLength == -1) Na\&}GSf^  
{ n~,6!S  
System.err.println("File Length is not known!"); f`}u9!jVR  
} \hJLa  
else if(nFileLength == -2) s$^ 2Cuhv  
{ *R&77 o7  
System.err.println("File is not access!"); _)CCD33$  
} JWt
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else @&h_+|:-  
{ wC1)\ld  
for(int i=0;i<nStartPos.length;i++)
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{ 8v)Z/R-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *eAt'  
} Dmtsu2o  
for(int i=0;i<nEndPos.length-1;i++) X?8bb! g%Q  
{ "t{D5{q|[k  
nEndPos = nStartPos[i+1]; dDe$<g5L4  
} ZB}zT9JaE  
nEndPos[nEndPos.length-1] = nFileLength; Swv =gu  
} 7n#Mh-vq  
} +
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]xJ2;{JWsO  
//启动子线程 )q7!CG'oY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %F*h}i  
for(int i=0;i<nStartPos.length;i++) !&8B8jHqA  
{ YZ0Q?7l7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =rNI&K_<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Yu%ZwTvw  
nStartPos,nEndPos,i); c"'JMq  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `?"[u"*  
fileSplitterFetch.start(); ds+0y;vc  
} .|6Wmn-uS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uQkFFWS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ][Cg8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", JOq&(AZe  
nEndPos = " + nFileLength); {NIE:MXX  
// fileSplitterFetch[nPos.length-1].start(); yzCamm4~0  
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//等待子线程结束 "qY_O/Eg]]  
//int count = 0; b;e*`f8T3c  
//是否结束while循环 ADZU?7)  
boolean breakWhile = false; ^X?3e1om  
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while(!bStop) X04JQLhy"  
{ i\k>2df  
write_nPos(); &FzZpH  
Utility.sleep(500); ]OA8H[U-eA  
breakWhile = true; ,dk!hm u  
.{#J2}+[_}  
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for(int i=0;i<nStartPos.length;i++) #ruL+-8!<  
{ 7pz #%Hf  
if(!fileSplitterFetch.bDownOver) )1!*N)$  
{ }7|UA%xz  
breakWhile = false; g)~"-uQQ  
break; ^b`aO$  
} +dSO?Y]  
} H(j983  
if(breakWhile) O9[Dae{i  
break; KdtQJ:_`k  
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//count++; s(Llz]E~ZX  
//if(count>4) niJtgK:H^  
// siteStop(); 9TbRrS09  
} &,~Oi(SX5  
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System.err.println("文件下载结束！"); =;?afUj  
} j>-O'CO
 
catch(Exception e){e.printStackTrace ();} ^9*kZV<K  
} qt!0#z8  
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^
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//获得文件长度 I[v6Y^{q  
public long getFileSize() ^J-\s_)"  
{ z->[:)c  
int nFileLength = -1; _)?59  
try{ Xe7/  
URL url = new URL(siteInfoBean.getSSiteURL()); X1PXX!]lo[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  &@h(6  
httpConnection.setRequestProperty("User-Agent","NetFox"); FH}2wO~_  
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int responseCode=httpConnection.getResponseCode(); ^\ocH|D  
if(responseCode>=400) YZyV   
{ Yy3g7!K5E  
processErrorCode(responseCode); `}Z`aK  
return -2; //-2 represent access is error 7)#8p@Q  
} mxfmK +'_  
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String sHeader; 3q*p#l~  
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for(int i=1;;i++) |)}&:xA%  
{ +zf[Im%E  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;*}tbh3;.  
//Utility.log(in.readLine()); Z&W*@(dX  
sHeader=httpConnection.getHeaderFieldKey(i); L.tW]43K  
if(sHeader!=null) X&14;lu%p  
{
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if(sHeader.equals("Content-Length")) FZ~^cK9g:  
{ g/f^|:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "F+m}GJ=a  
break; @zGz8IF  
} @&xWd{8'  
} ,z0~VS:g8  
else wXKg^%t\  
break; h1A
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} B9h'}460H  
} Yw_^]:~  
catch(IOException e){e.printStackTrace ();} dn}'B%  
catch(Exception e){e.printStackTrace ();} QopA'm  
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Utility.log(nFileLength); dlJc~|  
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return nFileLength; o<8SiVC2  
} W|-<ekH_u  
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#)b0&wyW6i  
//保存下载信息（文件指针位置） N,ysv/zq7  
private void write_nPos() 'M!*Ge  
{ NPjNkpWm&=  
try{ ki=]#]rg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]b'"l  
output.writeInt(nStartPos.length); f)#rBAkt  
for(int i=0;i<nStartPos.length;i++) %s*F~E  
{ q'1 86L87  
// output.writeLong(nPos); e.VR9O]G  
output.writeLong(fileSplitterFetch.nStartPos); - xKa-3  
output.writeLong(fileSplitterFetch.nEndPos); O~DdM
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} .h r$<]  
output.close(); u%b.#!  
} 7Q>bJ Ek7  
catch(IOException e){e.printStackTrace ();} Bm4fdf#A]  
catch(Exception e){e.printStackTrace ();} @aY>pr5!  
} tLSM]Q  
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//读取保存的下载信息（文件指针位置） hywy(b3  
private void read_nPos() m4x8W2q  
{ ni~1)"U.  
try{ , G9{:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _MxKfah'  
int nCount = input.readInt(); b`& :`  
nStartPos = new long[nCount]; Zg=jDPt}  
nEndPos = new long[nCount]; 6BH P#B2j  
for(int i=0;i<nStartPos.length;i++) CXd/M~:!  
{ p,K!'\  
nStartPos = input.readLong(); x=YV*  
nEndPos = input.readLong();
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} n@_aTY  
input.close(); [Ufx=BPx3  
} |f{(MMlj  
catch(IOException e){e.printStackTrace ();} EK2mJCC|  
catch(Exception e){e.printStackTrace ();} =.(~`ici~  
} sg%Ptp  
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private void processErrorCode(int nErrorCode) nxhn|v  
{ 8>AS
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System.err.println("Error Code : " + nErrorCode); 'bn$"A"{o  
} hQ\W~3S55  
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//停止文件下载 @FaK/lKK  
public void siteStop() 9CPr/q9'  
{ AQjf\i  
bStop = true; s`I]>e  
for(int i=0;i<nStartPos.length;i++) ICD;a  
fileSplitterFetch.splitterStop(); H6Q!~o\"H  
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} b*TQKYT  
} i%n9RuULh  
//负责部分文件的抓取 j]'ybpMT"  
**FileSplitterFetch.java m8<.TCIQ  
*/ fb?YDM  
package NetFox; cP^c}e*;NS  
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import java.io.*; Nin7AOO  
import java.net.*; &\e8c g  
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public class FileSplitterFetch extends Thread { D9%t67s  
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String sURL; //File URL 1T0s UIY  
long nStartPos; //File Snippet Start Position {xRO.699  
long nEndPos; //File Snippet End Position u[6aSqwC|  
int nThreadID; //Thread's ID qCy SL lp0  
boolean bDownOver = false; //Downing is over dmPAPCm%y  
boolean bStop = false; //Stop identical z8<"  
FileAccessI fileAccessI = null; //File Access interface  ?)2;W  
'.*`PN5mDq  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \{.c0  
{ ?fX`z(Z  
this.sURL = sURL; JnPwqIF1  
this.nStartPos = nStart; yVt
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this.nEndPos = nEnd; ,:xses*7  
nThreadID = id; Np@RK1}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =)f5JwZPG  
} `{H!V~42  
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public void run() g3TqTs  
{ 51 "v`O+  
while(nStartPos < nEndPos && !bStop) 
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{ o?5;l`.L}  
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try{
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URL url = new URL(sURL); IgEVz^W?h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^K0oJg.E  
httpConnection.setRequestProperty("User-Agent","NetFox"); _-z;  
String sProperty = "bytes="+nStartPos+"-"; Bpp(5  
httpConnection.setRequestProperty("RANGE",sProperty); O'S9y  
Utility.log(sProperty); UV\&9>@L  
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InputStream input = httpConnection.getInputStream(); eA-$TSWh  
//logResponseHead(httpConnection); LfMN 'Cb  
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byte[] b = new byte[1024]; +r$VrNVs  
int nRead; !RwMUnp  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >'v{o{k|C  
{ $d Nmq  
nStartPos += fileAccessI.write(b,0,nRead); GRAPv|u9[  
//if(nThreadID == 1) 6\RZ[g
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &:#"APX  
} |`O210B@  
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Utility.log("Thread " + nThreadID + " is over!"); +<'>~lDg  
bDownOver = true; b$Q#Fv&P  
//nPos = fileAccessI.write (b,0,nRead); r TK)jxklX  
} Vo9FlYj  
catch(Exception e){e.printStackTrace ();} /gP"X1.  
} PDb7h  
} KNSMx<GP  
;
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//打印回应的头信息 KQCF "  
public void logResponseHead(HttpURLConnection con) RpzW-  
{ BP=<TRp.  
for(int i=1;;i++) te+r.(p  
{ Oe&gTXo  
String header=con.getHeaderFieldKey(i); a.up&g_$  
if(header!=null) \iAs  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |fPR7-  
Utility.log(header+" : "+con.getHeaderField(header)); 7*@BCu6  
else O7yIFqI=/  
break; ^\w!D{Y7Q  
} bl[2VM7P  
} /e7BW0$1  
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public void splitterStop() Nx<fj=VJ  
{ AizLzR$OG  
bStop = true; _.5ABE  
} zZiga q"  
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} T*rz#O
  
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/* $`_xP1bUT  
**FileAccess.java `A$zLqz)Vm  
*//文件访问(定位，写) v8\pOI}c  
package NetFox; 4x_# 1 -  
import java.io.*; =/bC0bb{i  
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public class FileAccessI implements Serializable{ W@61rT}c  
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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 A3Y}|7QA  
RandomAccessFile oSavedFile; -!X\xA/KN  
long nPos; =]P|!$!}0  
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public FileAccessI() throws IOException Q`BB@E  
{ sLW e \o  
this("",0); S{zl<>+  
} (ljoD[kZ  
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public FileAccessI(String sName,long nPos) throws IOException %RXFgm!{f  
{ :@J.!dokF  
oSavedFile = new RandomAccessFile(sName,"rw"); v.Xmrry  
this.nPos = nPos; CwsC)]{/o  
oSavedFile.seek(nPos); b#:!b  
} @<B$LJ|jdG  
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public synchronized int write(byte[] b,int nStart,int nLen) _tfi6UQ&lY  
{ rG{,8*  
int n = -1; ^'$P[  
try{ c)zwyBz  
oSavedFile.write(b,nStart,nLen); y@\J7 h:  
n = nLen; E 7"`D\*  
} mxl"Y&l2<  
catch(IOException e) 2,G9~<t  
{ 6Wc.iomx8  
e.printStackTrace (); d.p%jVO)"  
} z=Khbh  
|%fM*F^7/  
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return n; \(ju0qFqH  
} Hq "l`  
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} a<&GsDw  
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/* ^(1S`z$  
**SiteInfoBean.java L+NrU+:=C  
*/ aaFt=7(K  
package NetFox; n!%'%%o2v  
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public class SiteInfoBean { zN,2 (v"  
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private String sSiteURL; //Site's URL }Bn
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private String sFilePath; //Saved File's Path ] F2
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private String sFileName; //Saved File's Name 6_O3/   
private int nSplitter; //Count of Splited Downloading File #~6au6LMC  
n^%",*8gD*  
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public SiteInfoBean() YF<U'EVU-  
{//nSplitter的缺省值为5 9NausE40  
//default value of nSplitter is 5 |Q*{yvfEo  
this("","","",5); ]xN)>A2  
} wak'L5GQE  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w*B4>FYg  
{ tz/NR/[  
sSiteURL= sURL; (zIIC"~5  
sFilePath = sPath; KU (g Zy  
sFileName = sName; XJZS}Z7h  
this.nSplitter = nSpiltter; 3nX={72<b  
kr>F=|R]  
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} Qk`LBv
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R![4|
FR  
public String getSSiteURL() 8 J;\Z  
{ m-XS_5x\  
return sSiteURL; 7r wNjY#  
} eWTbHF  
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public void setSSiteURL(String value) +<w\K*  
{ btWvoKO*  
sSiteURL = value; p+; La  
} >PONu]^  
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public String getSFilePath() .|<+-Rsj  
{ b]Z>P{ j  
return sFilePath; ?qR11A};tG  
} c<]~q1  
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.yb=I6D;<3  
public void setSFilePath(String value) 5nv1%48Ri  
{ d2(3 ,  
sFilePath = value; ]c\d][R N  
} GNab\M.  
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public String getSFileName() jxTYW)E   
{ *W$bhC'w  
return sFileName; EN{o3@ O'  
} CCU<t Q  
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public void setSFileName(String value) %rq/&#jC  
{ fe!{vrS  
sFileName = value; 8N9X1Mb|  
} g<PglRr"  
NH0uK  
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public int getNSplitter() 5Za%EaW%G  
{ ,@0D_&JAl  
return nSplitter; $&jte_hv  
} %#iu  
u @
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public void setNSplitter(int nCount) @tg4rl  
{ k`h#.B J  
nSplitter = nCount; 0=Mu|G|Z  
} 5Sz}gP('  
}
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/* NGVl/Qd  
**Utility.java R(on[g_1  
*/ JUdQ Q  
package NetFox; a<CACWsN.T  
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public class Utility { ]oxi~TwY^  
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(
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public Utility() Er@OmNT  
{ )%vnl~i!  
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} 1
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uS7kkzt-x  
//线程睡眠 v:?l C<,  
public static void sleep(int nSecond) 5&TH\2u  
{ ppzQh1  
try{ qB5.of[N!  
Thread.sleep(nSecond); t4Pi <m:7  
} ;"|QW?>$D  
catch(Exception e) ()e|BFL.  
{ cG,zO-H  
e.printStackTrace (); vW4n>h}]  
} OTzuOP8  
} #*X\pjZ  
$rm/{i_7  
//日志 {BzE  
public static void log(String sMsg) (!%9#  
{ uYC1}Y5N  
System.err.println(sMsg); .zv BV_I  
} n50WHlMtt  
+ f,Kt9Cy  
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public static void log(int sMsg) `#"xgOSP>  
{ ?OS0.  
System.err.println(sMsg); Z):Nd9  
} i!EAs`$o`  
} qKTzigjj  
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8p]9A,Uq&  
/* xJ9aFpTC  
**TestMethod.java |enb5b78  
*/ Lg{M<Q)4  
package NetFox; -\n%K
  
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public class TestMethod { Q89fXi0Ivb  
ty'/i!/\  
/xj`'8  
public TestMethod() LGK@taw^  
{ ///xx/weblogic60b2_win.exe et?FX K"y  
try{ "SRS{-p0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); l=ZD&uK  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /36gf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &x7iEbRs  
fileFetch.start(); GSW%~9WBa  
} nc6PSj X  
catch(Exception e){e.printStackTrace ();} SDB \6[D  
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} _s*p$/V\  
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public static void main(String[] args) kc(m.k!|f\  
{ @S:T8 *~}  
new TestMethod(); a~ dgf:e`  
} \&b 9  
}  TD%&9$F  
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