http断点续传简单实现（java)

/* C_}]`[  
**SiteFileFetch.java HmGWht6R  
*/ oq
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package NetFox; {3mRq"e  
import java.io.*; EHJ.T~X  
import java.net.*; ( Y[Q,  
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public class SiteFileFetch extends Thread { ,f%S'(>w  
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SiteInfoBean siteInfoBean = null; //文件信息Bean zFfr.g;L  
long[] nStartPos; //开始位置 8b&/k8i:  
long[] nEndPos; //结束位置 _`j7clEz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 w,.TTTad  
long nFileLength; //文件长度 e8a+2.!&\  
boolean bFirst = true; //是否第一次取文件 y'.p&QH'`  
boolean bStop = false; //停止标志 sUO`uqZV  
File tmpFile; //文件下载的临时信息 z\W64^'"Z  
DataOutputStream output; //输出到文件的输出流 =4YhG;%  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -l*|M(
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public SiteFileFetch(SiteInfoBean bean) throws IOException &jJL"gq"  
{ \;Biq`  
siteInfoBean = bean; F0TB<1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); AO4U}?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,?%Zc$\LW  
if(tmpFile.exists ()) m.rmM`  
{ +Mb.:_7'  
bFirst = false; l_d5oAh   
read_nPos(); _ ]ipajT  
} &'`g#N  
else F v2-(  
{ "%w u2%i  
nStartPos = new long[bean.getNSplitter()]; s/#!VnU6  
nEndPos = new long[bean.getNSplitter()]; m+[Ux{$  
} c7k~S-nU  
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=
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} rglXs  
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public void run() }o(-=lF  
{ PJ%C N(0  
//获得文件长度 kVMg 1I@  
//分割文件 &U#|uc!+  
//实例FileSplitterFetch QZ  
//启动FileSplitterFetch线程 YK'<NE3 4  
//等待子线程返回 n b?lTX~  
try{ +7.',@8_V  
if(bFirst) BX7kO0j  
{ Cl7xt}I  
nFileLength = getFileSize(); T.BW H2gRP  
if(nFileLength == -1) zTSTEOP}%Y  
{ 6%_nZvRv  
System.err.println("File Length is not known!"); IOmfF[  
} .t
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else if(nFileLength == -2) ]w8(&,PP  
{ FcU SE  
System.err.println("File is not access!"); R__OP`!  
} R&k<AZ  
else \
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{ 8Fu(Ft^9  
for(int i=0;i<nStartPos.length;i++) .Yn_*L+4*  
{ kn4`Fa;)O  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); g8% &RG  
} #q=Efn
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for(int i=0;i<nEndPos.length-1;i++) +a+Om73B2  
{ ^hM4j{
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nEndPos = nStartPos[i+1]; *.t7G  
} .W!i7  
nEndPos[nEndPos.length-1] = nFileLength; (hbyEQhF  
} *^ZV8c}  
} V**~m9f  
VU3upy<  
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//启动子线程 YU'E@t5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; sUQ@7sTj  
for(int i=0;i<nStartPos.length;i++)
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{ hHnYtq  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d\8l`Krs[_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9W2Vo [(  
nStartPos,nEndPos,i);  x'<X!gw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '\iCP1>+S  
fileSplitterFetch.start(); "+G8d'%YV  
} W^l-Y%a/o  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oZ|\vA%4^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z<?)Rq"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )jP1or  
nEndPos = " + nFileLength); S.NPZ39}ZE  
// fileSplitterFetch[nPos.length-1].start(); 2c*GuF9(0  
x s|FE3:a  
h S&R(m  
//等待子线程结束 +cN8Y}V  
//int count = 0; .aQ \jA  
//是否结束while循环 1mG-}  
boolean breakWhile = false; 2P0*NQ  
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while(!bStop) ZUd
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{ r;N|)  
write_nPos(); u'BaKWPS  
Utility.sleep(500); 4|?;TE5  
breakWhile = true; 1=V-V<  
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for(int i=0;i<nStartPos.length;i++) wnC81$1l~  
{ S<Xf>-8w  
if(!fileSplitterFetch.bDownOver) &%J08l6  
{ UJ   
breakWhile = false; <RL]  
break;
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} /%^#8<=|U  
} 4Fr  
if(breakWhile) >z@0.pN]7  
break; jse&DQ  
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sXFZWj}\  
//count++; Cw&KVw*  
//if(count>4) xJ.M;SF4  
// siteStop(); utV_W&  
} 0</);g}  
,z=LY5_z)  
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System.err.println("文件下载结束！"); PCtzl)  
} *s3/!K  
catch(Exception e){e.printStackTrace ();} 7@W>E;go  
} X"eYK/7  
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//获得文件长度 4o5t#qP5$S  
public long getFileSize() Jln:`!#fDf  
{ j#4kY R{  
int nFileLength = -1; o ^uA">GH  
try{ ^U/O!GK  
URL url = new URL(siteInfoBean.getSSiteURL()); u=e{]Ax#}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N8df8=.kw  
httpConnection.setRequestProperty("User-Agent","NetFox"); $[ *w"iQ  
,I;>aE<#  
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int responseCode=httpConnection.getResponseCode(); ,eS)e+yzc2  
if(responseCode>=400) "\yT7?},  
{ 2GG2jky{/  
processErrorCode(responseCode); zfdl45  
return -2; //-2 represent access is error VUuE T  
} 2&cT~ZX&'  
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String sHeader; qf-8<{T  
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for(int i=1;;i++) 'V>-QD%1  
{ (/$^uWj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); RxQ*  
//Utility.log(in.readLine()); E"IZ6)Q  
sHeader=httpConnection.getHeaderFieldKey(i); Dw"\/p:-3  
if(sHeader!=null) ;n;p@Uu[ b  
{ Q/Rqa5LI:  
if(sHeader.equals("Content-Length")) h{qgEIk&  
{ +b6v!7_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); yB!dp;gM{  
break; |I=T@1_D  
} -yg7;ff  
} `WS&rmq&'  
else v"0J&7!J  
break; DHRlWQox  
} -Lg Ei3m  
} dc'Y`e  
catch(IOException e){e.printStackTrace ();} izR"+v  
catch(Exception e){e.printStackTrace ();} ~}Pfu  
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Utility.log(nFileLength); |uJ
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return nFileLength; ia? c0xL  
} B)UZ`?>c  
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RM/ 0A|  
//保存下载信息（文件指针位置） fN2lLn9/u  
private void write_nPos() CvdN"k  
{ -:rUw$3J  
try{ wuo,kM  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8FhdN  
output.writeInt(nStartPos.length); iURe([@  
for(int i=0;i<nStartPos.length;i++) B-mowmJ3dg  
{ }-2|XD%]  
// output.writeLong(nPos); |':{lH6+1  
output.writeLong(fileSplitterFetch.nStartPos); Y4YJJYvD  
output.writeLong(fileSplitterFetch.nEndPos); .RL=xb|[  
} {4PwLCy  
output.close(); 9tnD=A<PS  
} !n%j)`0M  
catch(IOException e){e.printStackTrace ();} D6Wa.,r  
catch(Exception e){e.printStackTrace ();} 2&5K.Ui%  
} H,NF;QPPC  
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//读取保存的下载信息（文件指针位置） qxj(p o  
private void read_nPos() "Y.y:Vv;  
{ p K$`$H
 
try{ (tO\)aS=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8?C5L8)  
int nCount = input.readInt(); (-co.  
nStartPos = new long[nCount]; 5-A\9UC*@  
nEndPos = new long[nCount]; _VXN#
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for(int i=0;i<nStartPos.length;i++) "gwSJ~:ds  
{ *K;~!P  
nStartPos = input.readLong(); -n;}n:wL  
nEndPos = input.readLong(); J~- 4C)  
}  AOx[  
input.close(); "Yy n/  
} t`QENXA}  
catch(IOException e){e.printStackTrace ();} Bbp|!+KP{(  
catch(Exception e){e.printStackTrace ();} TsZ@  
} LH6vLuf  
 =BrRYA  
_ x*3PE  
private void processErrorCode(int nErrorCode) >R=|Wo`Ri  
{
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System.err.println("Error Code : " + nErrorCode); fXB0j;A  
} Vw"\
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//停止文件下载 13wE"-  
public void siteStop() 048kPXm`  
{ XX~,>Q}H=  
bStop = true; ch]29  
for(int i=0;i<nStartPos.length;i++) wyG;8I  
fileSplitterFetch.splitterStop(); yDS4h(^  
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} nj4/#W  
} dqAw5[qMJ  
//负责部分文件的抓取 eDB;cN  
**FileSplitterFetch.java -{A<.a3P}=  
*/ J8D,ZfPN`d  
package NetFox; o"SMbj  
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import java.io.*; FPTK`Gd0  
import java.net.*; |K~Nw&rZ]  
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public class FileSplitterFetch extends Thread { 'f|o{  
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ET >](l9  
String sURL; //File URL :H[6Lg\*  
long nStartPos; //File Snippet Start Position Aa]"  
long nEndPos; //File Snippet End Position U<-D(J
  
int nThreadID; //Thread's ID 8r!zBKq2~  
boolean bDownOver = false; //Downing is over k_R"CKd  
boolean bStop = false; //Stop identical F<w/PMb  
FileAccessI fileAccessI = null; //File Access interface bjS{(  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Np)lI
GE  
{ :i7;w%
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this.sURL = sURL; =qIyqbXz  
this.nStartPos = nStart; )_NO4`ejs/  
this.nEndPos = nEnd; Q7A MRrN  
nThreadID = id; Vq2$'lY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;=UsAB]  
} -%dCw6aX+  
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public void run() fn!KQ`,#  
{ 4`R(?  
while(nStartPos < nEndPos && !bStop)
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{ %%wNZ{  
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try{ ]
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URL url = new URL(sURL); lHIM}~#;nd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9k=3u;$v  
httpConnection.setRequestProperty("User-Agent","NetFox"); bu"!jHPB  
String sProperty = "bytes="+nStartPos+"-"; a'z7(8$$  
httpConnection.setRequestProperty("RANGE",sProperty); ~v"L!=~G;a  
Utility.log(sProperty); 1i] ^{;]  
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InputStream input = httpConnection.getInputStream(); .}*
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//logResponseHead(httpConnection); UY2OZ&&  
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byte[] b = new byte[1024]; >"<Wjr8W!$  
int nRead; 3yXY.>'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) EZ`{
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{  RX5dO%  
nStartPos += fileAccessI.write(b,0,nRead); s|ITsz0,td  
//if(nThreadID == 1) b_):MQ1
{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xP,hTE  
} YgoBHE0#  
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Utility.log("Thread " + nThreadID + " is over!"); I`p;F!s  
bDownOver = true; as_PoCoss  
//nPos = fileAccessI.write (b,0,nRead); C6y&#uX\  
} eR"<33{  
catch(Exception e){e.printStackTrace ();} BF<ikilR  
} Z(!\%mn  
} @ry_nKr9  
2 Vrw  
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//打印回应的头信息 IaXeRq?<  
public void logResponseHead(HttpURLConnection con) .6'q
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{ tnG# IU *  
for(int i=1;;i++) pHJ
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{ 6K<K  
String header=con.getHeaderFieldKey(i); Tu7QCr5*  
if(header!=null) r>U@3%0&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); O8.5}>gDn.  
Utility.log(header+" : "+con.getHeaderField(header)); ia 73?*mXT  
else 3%ZOKb"D*  
break; m%e68c  
} t<viX's  
} VU d\QR-  
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#Vha7  
public void splitterStop() I.k *GW  
{ .VzT:4-<Q"  
bStop = true; 1y4  
} <A'$%`6m  
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8*T=Xei8  
} E+w<R
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/* 5[u]E~Fl}  
**FileAccess.java xUistwq  
*//文件访问(定位，写) Vy,DN~ag  
package NetFox; hfy_3}_  
import java.io.*; "6?0h[uff  
{jX2}  
J6aef^>  
public class FileAccessI implements Serializable{ 3kMf!VL  
FG*r'tC~r  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Np0u,t%vs  
RandomAccessFile oSavedFile; q#=(e:aCb  
long nPos; 5N&?KA-  
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public FileAccessI() throws IOException Eg3q!J&Z  
{ C-[eaHJ'$  
this("",0); 'ub@]ru|  
} $'hEz/  
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+&2%+[nBZ  
public FileAccessI(String sName,long nPos) throws IOException %n:k#  
{ b`O'1r\Y;  
oSavedFile = new RandomAccessFile(sName,"rw"); d4c8~L H-  
this.nPos = nPos; nK%LRcAs  
oSavedFile.seek(nPos); QW(Mz Hg  
} }@+:\   
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[^98fAlz6  
public synchronized int write(byte[] b,int nStart,int nLen) 7Da`   
{ }2<7%FL  
int n = -1; SJ>vwmA4  
try{ d,n 'n  
oSavedFile.write(b,nStart,nLen); [e}]}t8m  
n = nLen; Y\?"WGL)p  
} >e[i5  
catch(IOException e) (jl D+Y_  
{ 6MMOf\   
e.printStackTrace (); BeoDKdAwY  
} JHTSUq  
Hn+~5@.  
!NvI:C_4|  
return n; l3I:Q^x@  
} r:ptQo`1-  
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} "]b<uV
  
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/* O5nD+qTQ#  
**SiteInfoBean.java 9H`XeQ.  
*/ |_aa&v~  
package NetFox; GH:jH]u!V  
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\$T(t/$9  
public class SiteInfoBean { T&u5ki4NE  
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private String sSiteURL; //Site's URL Cl8Cg~2  
private String sFilePath; //Saved File's Path fN^8{w/O  
private String sFileName; //Saved File's Name \B,@`dw  
private int nSplitter; //Count of Splited Downloading File i
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h-<
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public SiteInfoBean() dufu|BL|}  
{//nSplitter的缺省值为5 Ata:^q
I  
//default value of nSplitter is 5 :hk5 .[  
this("","","",5); Y;^l%ePuW  
} d K3*;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) HjD8u`qQ  
{ hxd`OG<gF  
sSiteURL= sURL; Eq9
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sFilePath = sPath; ;m{1_1  
sFileName = sName; BdblLUGK#  
this.nSplitter = nSpiltter; cZU=o\  
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} .P%bkD6M  
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public String getSSiteURL() 4`]^@"{  
{ ]i ,{  
return sSiteURL; D_^ nI:  
} VfC<WVYiZ  
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public void setSSiteURL(String value) ]]9R mh=  
{ $f=J2&D,Cz  
sSiteURL = value; {xB!EQ"  
} f:|1_j  
6J6BF%  
.A{tQ1&_  
public String getSFilePath() QIvVcfM^  
{ hl(hJfp  
return sFilePath; BmMGx8P  
} 6x[}g  
A_ N;   
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public void setSFilePath(String value) %wvdn  
{ yyRiP|hJ  
sFilePath = value; '(yAfL 9}  
} g:D>.lKd  
|[ k.ii6iO  
~>Fu5i $i  
public String getSFileName() L Mbn  
{ i8[t=6Rm@  
return sFileName; 0gy/:T  
} %D}kD6=  
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public void setSFileName(String value) D4-ifsP  
{ JG!m
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sFileName = value; Cc' 37~6~P  
} +wvWwie  
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7>Ouqxh21  
public int getNSplitter() K'Tm_"[u  
{ kmsb hYM)  
return nSplitter; eH3JyzzP,  
} &5spTMw8  
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&<5zqsNJ\a  
public void setNSplitter(int nCount) wh\}d4gN  
{ 2"kLdD  
nSplitter = nCount; YY((V@|K  
} 7BjJhs  
} (Hz^)5(~  
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# 448-8x  
/* C]eSizS.  
**Utility.java '}JhzKNj  
*/ X!
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package NetFox; B=y
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public class Utility { Vb4#,  
o]` *M|  
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public Utility() .TR9975  
{ 7he,?T)vD  
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f/NH:1)y  
} be{H$9'
 
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//线程睡眠 "XKy
#[d2  
public static void sleep(int nSecond) m
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{ #`iB`|  
try{ .hP D$o  
Thread.sleep(nSecond); ARVf[BAJ-*  
} 2d(e:rh]  
catch(Exception e) wd^':  
{ ;%5N%
0,  
e.printStackTrace (); YTpSHp
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} ia~HQ$'+n  
} KB,j7 ~V  
;|5F[  
//日志 zh`<WN&H  
public static void log(String sMsg) wj<6kG  
{ Eh;'S"{/?j  
System.err.println(sMsg); # E^1|:  
} fue(UMF~  
SSg8}m5)Q  
}6}l7x  
public static void log(int sMsg) E7Ul;d  
{ '&R2U_  
System.err.println(sMsg); @=Uh',F  
} i2A8
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} A*R^n}sh  
|y# Jx  
*74MWF@IY  
/* v ~?qz5:K~  
**TestMethod.java o&zJ=k[4  
*/ cAqLE\h  
package NetFox; fZzoAzfv2  
KKPh~ThC  
E`0?  
public class TestMethod { C8:f_mJU  
r1m]HFN  
'8.r-`l(  
public TestMethod() o>i4CCU+  
{ ///xx/weblogic60b2_win.exe #u
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try{ ]G=L=D^cK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \fr~
  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); IH&|Tcf\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7P5)Z-K[  
fileFetch.start(); Rz:]\jcIT/  
} gHEu/8E  
catch(Exception e){e.printStackTrace ();} Ugt/rf5n  
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[{,T.;'<j  
} Apag{Z]^B  
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9r<J"%*Q  
public static void main(String[] args) x8\?}UnB  
{ y`5 9A  
new TestMethod(); Jr!JHC9i  
} D~iz+{Q4  
} Uh4%}-;  
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