http断点续传简单实现（java)

/* _<}oB
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**SiteFileFetch.java _X;xW#go  
*/ c'O"</  
package NetFox; SI\ O>a9{  
import java.io.*; [&eG>zF"  
import java.net.*; Pg4go10|  
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public class SiteFileFetch extends Thread { _D.4=2@|l8  
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SiteInfoBean siteInfoBean = null; //文件信息Bean <Ukeq0  
long[] nStartPos; //开始位置 >W>3w  
long[] nEndPos; //结束位置 S3Dmc\f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 pm` f?
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long nFileLength; //文件长度 ;2N: =Rv  
boolean bFirst = true; //是否第一次取文件 GBSuTu8  
boolean bStop = false; //停止标志 wjy<{I  
File tmpFile; //文件下载的临时信息 CT{mzC8  
DataOutputStream output; //输出到文件的输出流 0(qtn9;=2  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Y+)qb);  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ky[s&>02  
{ zt!)7HBo  
siteInfoBean = bean; '"C& dia  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); XmJ?oPr7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); JO-FnoQK  
if(tmpFile.exists ()) ,
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{ o#uhPUZ
 
bFirst = false; /JjSx/  
read_nPos(); t9~Y ?  
} yU|=)p5  
else SDu%rr7sQ  
{ aOhi<I`*  
nStartPos = new long[bean.getNSplitter()]; &0x;60b  
nEndPos = new long[bean.getNSplitter()]; &iO53I^r/  
} q~. .Z Y`7  
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} E3V_qT8  
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public void run() XyYP!<].C  
{ @rE+H 5  
//获得文件长度 3[UaK`/1C  
//分割文件 \*mKctpz]6  
//实例FileSplitterFetch RveEA/&&  
//启动FileSplitterFetch线程 RDxvN:v  
//等待子线程返回 a\m0X@Q  
try{ =zW`+++3  
if(bFirst) W~& QcSWqD  
{ Zt \3y  
nFileLength = getFileSize(); 04c`7[  
if(nFileLength == -1) _iH:>2p5R  
{ {!*dk V  
System.err.println("File Length is not known!"); 9w<k1j  
} o4H'  
else if(nFileLength == -2) /Py`a1  
{ 'XI-x[w  
System.err.println("File is not access!"); ow9Vj$m  
} m!WDXt  
else |!cM_&  
{ u vyvy  
for(int i=0;i<nStartPos.length;i++) DI\^&F)3T2  
{ $aY:Z_s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Lp
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} G(hzW%P  
for(int i=0;i<nEndPos.length-1;i++) ^o(C\\>{&  
{ T#3`&[  
nEndPos = nStartPos[i+1]; l(3\ekU!  
} vPsf{[Kr  
nEndPos[nEndPos.length-1] = nFileLength; yHmNO*(  
} ]g]~!":  
} oF.H?lG7`  
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//启动子线程 i>PKE.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; wV"C ,*V  
for(int i=0;i<nStartPos.length;i++) `cqZ;(^  
{ 2(>=@q.1H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 89fl\18%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -hKtd3WbT  
nStartPos,nEndPos,i); <xAlp;8m5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S^  JUQx7  
fileSplitterFetch.start(); QW>(LGG=  
} z1LY|8$G  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p/?TU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); % ^&D,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0zqTX< A  
nEndPos = " + nFileLength); B=hJ*;:p  
// fileSplitterFetch[nPos.length-1].start(); &:Sb$+z  
>}B~~C;  
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//等待子线程结束 f2FGod<CzN  
//int count = 0; zNQ|G1o  
//是否结束while循环 >Av%[G5=h#  
boolean breakWhile = false; p&(~c/0  
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while(!bStop) 0%5x&vx'S  
{ qYR+qSAJP  
write_nPos(); me/ae{  
Utility.sleep(500); oxL4* bqZ  
breakWhile = true; AZ
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4!tHJCq"  
/pDI \]  
for(int i=0;i<nStartPos.length;i++) YK|Y^TU^  
{ s\i.pd:Q  
if(!fileSplitterFetch.bDownOver) [E
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{ {T[/B"QZG  
breakWhile = false; YP vg(T  
break; Y/w) V
V  
} ?4}EhXR(  
} 1MzOHE
 
if(breakWhile) 7w=%aW|  
break; yi/jZX  
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$\@yH^hL  
//count++; O[fg
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//if(count>4) ]]Da/^K=Z  
// siteStop(); eX>X=Ku  
} JSQ*8wDcl  
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System.err.println("文件下载结束！"); k6 f;A  
} |79!exVMBp  
catch(Exception e){e.printStackTrace ();}  <XxFR  
} `'`T'
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i>[1^~;  
//获得文件长度 jsvD[\P  
public long getFileSize() \HOOWaapN  
{ E$[\Fk}S  
int nFileLength = -1; S:"t]gbF =  
try{ %.R_[.W  
URL url = new URL(siteInfoBean.getSSiteURL()); ngN_,x7yc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eMvb*X6  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z qg(\  
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int responseCode=httpConnection.getResponseCode(); ]4>[y?k34  
if(responseCode>=400) b
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{ ^9UF Pij"  
processErrorCode(responseCode); >9g`9hB  
return -2; //-2 represent access is error pTK|u!fs  
} 5yQv(<~*G
 
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String sHeader; n]@+<TA<uA  
}x1mpPND  
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for(int i=1;;i++) Mf&W<
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{ <8At=U  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); v;;X2 a1k  
//Utility.log(in.readLine()); puv*p%E  
sHeader=httpConnection.getHeaderFieldKey(i); "'}v0*[  
if(sHeader!=null) A D}}>v  
{ 22Y!u00D  
if(sHeader.equals("Content-Length")) lGnql1(  
{ Zn<(,e  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (:y,CsR}4  
break; 4j@kMe;RjZ  
} ySuLt@X  
} zA'gb'MmW  
else Ef_F#X0#  
break; L=$?q/=-  
} 93^(O8.  
} Hc&uE3=%sL  
catch(IOException e){e.printStackTrace ();} Xc9p;B>^Ts  
catch(Exception e){e.printStackTrace ();} <(bCz>o|  
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Utility.log(nFileLength); @!&Jgg53G  
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return nFileLength; Qw6KX#n  
} p-i.ITRS  
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//保存下载信息（文件指针位置） D*XZT{1g  
private void write_nPos() g]==!!^<D  
{ 0?6If+AC  
try{ :?$Sb8OuIL  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ER;lkF`RF  
output.writeInt(nStartPos.length); /H%<oAjp6  
for(int i=0;i<nStartPos.length;i++) 3I;xU(rv  
{ @`IXu$Wm(  
// output.writeLong(nPos); z)ft3(!  
output.writeLong(fileSplitterFetch.nStartPos); clq~ ;hx  
output.writeLong(fileSplitterFetch.nEndPos); Msv*}^>  
} /jZaU`  
output.close(); yUD_w  
} ~}7$uW0ol  
catch(IOException e){e.printStackTrace ();} C>Omng1>^  
catch(Exception e){e.printStackTrace ();}
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} Mz/]DJ8  
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//读取保存的下载信息（文件指针位置） 3WO#^}t  
private void read_nPos() t?]\M&i&  
{ kW<Yda<a  
try{ pBg|n=^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); b"R, p=M  
int nCount = input.readInt(); g+>=C   
nStartPos = new long[nCount]; l50|` 6t  
nEndPos = new long[nCount]; H-/; l54E  
for(int i=0;i<nStartPos.length;i++) 6m, KL5>W  
{ Ism^hyL  
nStartPos = input.readLong(); S+) l[0  
nEndPos = input.readLong(); ?AeHVQ :C  
} PwFQ#Z  
input.close(); >%uAQiU  
} :rz9M@7  
catch(IOException e){e.printStackTrace ();} p4m^ ~e  
catch(Exception e){e.printStackTrace ();} 1a($8>  
} DEUd[  
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private void processErrorCode(int nErrorCode) c N02roQl  
{ ] ?DDCew  
System.err.println("Error Code : " + nErrorCode); tr6jh=  
} 3W7;f!  
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<mv7HKVg  
//停止文件下载 ZQ,f
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public void siteStop() #dva0%-1  
{ E^Q@9C<!d  
bStop = true; j!zA+hF(  
for(int i=0;i<nStartPos.length;i++) 4zo4H~@gk  
fileSplitterFetch.splitterStop(); !Y ;H(.A/  
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} 7ei>L]gm%  
} L.C ^E7;Z_  
//负责部分文件的抓取 U}tl_5%)  
**FileSplitterFetch.java V,>+G6e  
*/ *'UhlFed  
package NetFox; D+@-XU<Lp<  
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import java.io.*; Zi 2o  
import java.net.*; |A ;o0pL  
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public class FileSplitterFetch extends Thread { 5SoZ$,a<e  
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String sURL; //File URL 0lX)Cl  
long nStartPos; //File Snippet Start Position e$CePLEj  
long nEndPos; //File Snippet End Position qSFc=Wwc  
int nThreadID; //Thread's ID vVI6m{zYV  
boolean bDownOver = false; //Downing is over rPRrx-A  
boolean bStop = false; //Stop identical !UBy%DN~k  
FileAccessI fileAccessI = null; //File Access interface jP1$qhp  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6OfdD
.y  
{ t9G}Yd[T  
this.sURL = sURL; 5;X {.2  
this.nStartPos = nStart; iLF^%!:X%  
this.nEndPos = nEnd; ~R :<Bw  
nThreadID = id; 7IA3q{P  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 z7-`Y9Ypd  
} k/df(cs  
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public void run() sCVI 2S!L  
{ (7IqY1W  
while(nStartPos < nEndPos && !bStop) <A)+|Y"^h6  
{ q
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try{ ,`;jvY~Ec  
URL url = new URL(sURL); ./#e1m?.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 
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httpConnection.setRequestProperty("User-Agent","NetFox"); HV ;;  
String sProperty = "bytes="+nStartPos+"-"; CXTt(-FT  
httpConnection.setRequestProperty("RANGE",sProperty); kGpV;F==*  
Utility.log(sProperty); Ee&hG[sx  
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InputStream input = httpConnection.getInputStream(); yc*<:(p  
//logResponseHead(httpConnection); >B0D/:R9  
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byte[] b = new byte[1024]; ue@8voZhS/  
int nRead; +W6Hva.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,*7H|de7  
{ R4V \B  
nStartPos += fileAccessI.write(b,0,nRead); HzE1r+3Q@  
//if(nThreadID == 1) j8pFgnQ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SC'BmR"ox  
} !/947Rn  
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,
 
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Utility.log("Thread " + nThreadID + " is over!"); .AXdo'&2i  
bDownOver = true; 7U,k 2LS  
//nPos = fileAccessI.write (b,0,nRead); \yM-O-{  
} &ik$L!iX  
catch(Exception e){e.printStackTrace ();} ]pWP?Ws  
} [Gh"ojt]w  
} opdu=i=E  
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//打印回应的头信息 :y\09)CJK  
public void logResponseHead(HttpURLConnection con) S."7+g7Ar  
{ I0DM=V>;  
for(int i=1;;i++) hm3jpWi8  
{ Y~az!8j;Z  
String header=con.getHeaderFieldKey(i); kBbl+1{H  
if(header!=null) Uh.Sc:trA  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9mQ#L<Ps  
Utility.log(header+" : "+con.getHeaderField(header)); vXb:  
else $&IpX M]  
break; z5 Bi=~=#  
} _Fizgs  
} \83sSw  
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public void splitterStop() uArR\k(  
{ MHo1 lrZa+  
bStop = true; [h4o7  
} k5@d! }#c  
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} %w7m\nw@  
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/* u?kD)5Nk  
**FileAccess.java !qA8Zky_  
*//文件访问(定位，写) |z~LzSJv  
package NetFox; khAqYu")  
import java.io.*; NhA#bn9y?  
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public class FileAccessI implements Serializable{ (;}tf~~r  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6^;^rUlm  
RandomAccessFile oSavedFile; Zn&k[?;Al  
long nPos; <qhBc:kc  
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public FileAccessI() throws IOException S$eDnw~$  
{ u g\w\b  
this("",0); Kd3QqVJBz1  
} w(BH247`  
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public FileAccessI(String sName,long nPos) throws IOException cXN _*%  
{ qX$u4I!,  
oSavedFile = new RandomAccessFile(sName,"rw"); 5h8o4  
this.nPos = nPos; kZVm
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oSavedFile.seek(nPos); z/1{OL  
} EA|k5W*b  
0Q~@F3N-\>  
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public synchronized int write(byte[] b,int nStart,int nLen) ni6r{eS
Q  
{ 
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int n = -1; $%PVJs  
try{ &[@\f^~  
oSavedFile.write(b,nStart,nLen); :.iyR  
n = nLen; S &JJIFftO  
} =MLf[
 
catch(IOException e) \k@Z7+&7  
{ dB;3.<S=  
e.printStackTrace (); "&lN\&:  
} Z0ReWrl;`  
~ y;y(4<  
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return n; t`G)b&3_O  
} :eOR-}p'  
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} f vLC_'M  
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/* '#Dg8/r!  
**SiteInfoBean.java {J]-<:XD  
*/ PuX
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package NetFox; :Q@)*kQH  
/smiopFcq  
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public class SiteInfoBean { ksWSMxm  
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private String sSiteURL; //Site's URL lKKERO5+  
private String sFilePath; //Saved File's Path ZA
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private String sFileName; //Saved File's Name zgKY4R{V  
private int nSplitter; //Count of Splited Downloading File v-`h>J!Nx  
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9"sDm}5%  
public SiteInfoBean() t`|,6qEG  
{//nSplitter的缺省值为5 V U~Dk);Bv  
//default value of nSplitter is 5 #Hu~}zy  
this("","","",5);  "0&N}  
} G'x 
.
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vR>o}%`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) z`$J_CjY  
{ H4<Nnd\   
sSiteURL= sURL; C!%:o/  
sFilePath = sPath; ;sPzOS9  
sFileName = sName; #[ -\lU|  
this.nSplitter = nSpiltter; K:r\{#9  
*t9eZ!_f?  
[!"XcFY:a  
} Q:Mh
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public String getSSiteURL() UQT'6* !  
{ Vhg1/EgUr  
return sSiteURL; mBk5+KyT  
} ijUzC>O+q  
:&VcB$  
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public void setSSiteURL(String value) O}Le]2'  
{ w'ybbv{c  
sSiteURL = value; =AOWeLk*G  
} Xl%0/o  
9E1W|KE  
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public String getSFilePath() x?r1s#88>  
{ rZwB>c  
return sFilePath; TGV  
} S~F`  
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public void setSFilePath(String value) .FP$ IWt/1  
{ 5/I_w0  
sFilePath = value; 7#2j>G{?]v  
} >n
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public String getSFileName() B0)]s<<  
{ `M@Ak2gcR+  
return sFileName; 0 bSA_  
} cF+ X,]=6  
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public void setSFileName(String value) N$alUx*  
{ O/OiQ^T  
sFileName = value; fA^Em)cs2  
} "="O >  
n:#TOU1ix<  
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public int getNSplitter() uV]ULm#,i
 
{ *l>0t]5YH  
return nSplitter; [CN$ScK,  
} $3P`DJo  
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_ PWj(});  
public void setNSplitter(int nCount) ]/dVRkZeAE  
{ z&+ zl6  
nSplitter = nCount; d;G~hVu  
}
@Hjea1@t  
} 8X7{vN_3K  
#hxyOq,  
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/* H{`{)mS  
**Utility.java $k2)8#\  
*/ w:ULi3  
package NetFox; 1B:aC|B  
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public class Utility { Dpqt;8"2L  
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public Utility() <8
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{ Z=$T1|  
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jNl/!l7B  
} -|_ir-j  
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//线程睡眠 4tc:.  
public static void sleep(int nSecond) "S!3m9_#  
{ <Gb %uny  
try{ 'Z8aPHD  
Thread.sleep(nSecond); >1|g5  
} -q>^ALf|@>  
catch(Exception e) fEnQE EU~P  
{ nkY@_N
 
e.printStackTrace (); !,&yyx.  
} X>l*v\F9  
} G*n2Ii  
j$@tK0P  
//日志 `rFAZcEj%  
public static void log(String sMsg) mP}#Ccji?  
{ wD9a#AgEd  
System.err.println(sMsg); KS<Jv;  
} xAdq+$><  
d>i13dAI  
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public static void log(int sMsg) h'5Cp(G  
{ W)=%mdxW0  
System.err.println(sMsg); Fvl`2W94;  
} h%}(h2W  
} <[Oo*:A!7  
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]|Zb\{  
/* 9O98Q6-s  
**TestMethod.java <@#PF$!  
*/ w G!u+  
package NetFox; b-<HXn_Fd  
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public class TestMethod { =_d%=m  
]H[8Z|i""  
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public TestMethod() k onoI&kV|  
{ ///xx/weblogic60b2_win.exe l(kr'x  
try{ P:!)9
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C7qYiSv  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); S*t%RZ~a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); h=+$>_&:  
fileFetch.start(); 4ke^*g K<  
}
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catch(Exception e){e.printStackTrace ();} t1i(;|8|  
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} uofLhy!  
$kz!zjC'  
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public static void main(String[] args) 2
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1  
{ Zhi})d3l  
new TestMethod(); U}AX0*S  
} WH$HI/%*m  
} 5cTY;@@  
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