http断点续传简单实现（java)

/* 9%DT0.D}$j  
**SiteFileFetch.java KS<Jv;  
*/ #$1$T  
package NetFox; 4E3g,%9u  
import java.io.*; ecHP &Z$  
import java.net.*; Wk7WK` >i  
#G;X' BN  
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public class SiteFileFetch extends Thread { SS3-+<z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean s3QEi^~
 
long[] nStartPos; //开始位置 "^rNr_  
long[] nEndPos; //结束位置 wyY*:{lZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 o'=VZT9  
long nFileLength; //文件长度 _6LoVS  
boolean bFirst = true; //是否第一次取文件 -T_\f?V88  
boolean bStop = false; //停止标志 _j ;
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File tmpFile; //文件下载的临时信息 t&RruwN_;  
DataOutputStream output; //输出到文件的输出流 O!F]^'!  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _%pAlo_6  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4<v;1   
{ u<Xog$esu  
siteInfoBean = bean; H~fdbR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .5Z_E O  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /L~m#HxWU  
if(tmpFile.exists ()) hC<14  
{ <d7xt*4  
bFirst = false; =!0I_L/  
read_nPos(); 1/iE`Si  
} &O1v,$}'  
else (FVX57  
{ *gqSWQ  
nStartPos = new long[bean.getNSplitter()]; Pv){sYUh  
nEndPos = new long[bean.getNSplitter()]; j}WByaZ&  
} h4`9Cfrq,  
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} NPJ.+
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public void run() @.$MzPQQI  
{ );JJ2Jlkd  
//获得文件长度 - q@
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//分割文件 8;zDg$(  
//实例FileSplitterFetch SG'JE}jzO  
//启动FileSplitterFetch线程 AK/:I>M  
//等待子线程返回 wK*PD&nN  
try{ ]0~qi@  
if(bFirst) bBE+jqi2  
{ Y1\K;;X  
nFileLength = getFileSize(); {B{i(6C(  
if(nFileLength == -1) j\2[H^   
{ n[" 9|  
System.err.println("File Length is not known!"); []}N  
} A,XfD}+:Z  
else if(nFileLength == -2) Ja [4A0.  
{ ]PX}b  
System.err.println("File is not access!"); Z)9R9s  
} %e=!nRc  
else O%JSViPw  
{ t4K56H.L?  
for(int i=0;i<nStartPos.length;i++) C0m\SNR  
{ =ApY9`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Q7a(P  
} ?q$P>guH6-  
for(int i=0;i<nEndPos.length-1;i++) '2v f|CX  
{ !v>ew9  
nEndPos = nStartPos[i+1]; dgc&[  
} T33|';k  
nEndPos[nEndPos.length-1] = nFileLength; u''BP.Y S  
} YoSQN
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} @ss):FwA  
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//启动子线程 Bc ^4 T1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #PAU'u 3{/  
for(int i=0;i<nStartPos.length;i++) 9g@NcJ]  
{ \E hr@g  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0m=(W^c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), uiMIz?+  
nStartPos,nEndPos,i); =5s$qb?#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0dt"ZSm  
fileSplitterFetch.start(); >oY^Gx  
} -c={+z "  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pVG>A&4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W~dE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", T$c+m\j6  
nEndPos = " + nFileLength); 8
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// fileSplitterFetch[nPos.length-1].start(); ^H=o3#P~L  
hyu}}0:  
_*`q(dYcf  
//等待子线程结束 >q9{  
//int count = 0; 0k1MKzi Q  
//是否结束while循环 MSYN1  
boolean breakWhile = false; $u5.!{Wq?  
,nYZxYLf+  
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while(!bStop) ?( 12aU  
{ 5 ,ZRP'oI  
write_nPos(); g:i*O^c@  
Utility.sleep(500); t)(v4^T  
breakWhile = true; JQT4N[rEE  
}x0Z( `  
:,YLx9i>  
for(int i=0;i<nStartPos.length;i++) RV92qn B  
{ wE2x:Ge:  
if(!fileSplitterFetch.bDownOver) #W5Yw>$  
{ /(zB0TEd  
breakWhile = false; D_ ug-<QT  
break; 3"tg+DncC  
} 3- )kwy6L  
} 9::YR;NY  
if(breakWhile) VjTAN=  
break; Cyf]`*  
3@HIpQM3  
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//count++; 7'UWRRsxUF  
//if(count>4) |"\lL9CT  
// siteStop(); 4vGbG:x  
} H%T3Pc  
)"~=7)~<^  
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System.err.println("文件下载结束！"); R
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} u'Pn(A@1R  
catch(Exception e){e.printStackTrace ();} jl@K!=q  
} Gf
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W_D%|Ub2X  
//获得文件长度 C~_q^fXJt  
public long getFileSize() hvcR.f)C>  
{ Cha?7F[xL  
int nFileLength = -1; d<?X3&J  
try{ 6#-Z@fz%  
URL url = new URL(siteInfoBean.getSSiteURL()); 1eF@_Y^a!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,whM22Af~{  
httpConnection.setRequestProperty("User-Agent","NetFox"); qAvvXs=5  
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int responseCode=httpConnection.getResponseCode(); -W6V,+of  
if(responseCode>=400) hhj ,rcsi  
{ J{x##p<F$  
processErrorCode(responseCode); cuNq9y;[  
return -2; //-2 represent access is error >rRjm+vg  
} )#mW7m9M#  
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String sHeader; >oB ?  
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for(int i=1;;i++) KK .cDAR  
{ s9kTuhoK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wEv*1y4  
//Utility.log(in.readLine()); rl41#6  
sHeader=httpConnection.getHeaderFieldKey(i); a6 *Y%?  
if(sHeader!=null) {cX7<7N  
{ B8>FCF&}E  
if(sHeader.equals("Content-Length")) 2nYiG)tg  
{ roL]v\tr  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^ M8k  
break; XSls]o s  
} -MsuBf  
} @US '{hO1p  
else ZS|Z98  
break; ,Zr YJ<  
} +Hi{/{k0N  
} iiQ||P}5  
catch(IOException e){e.printStackTrace ();} 2/UI>@By  
catch(Exception e){e.printStackTrace ();} P@-R5GK  
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Utility.log(nFileLength); HMFl/%z  
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return nFileLength; X%*brl$D  
}  S/)  
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}.w#X  
//保存下载信息（文件指针位置） >n#g9vK  
private void write_nPos() VQ
/ <09e  
{ *%z<P~}  
try{ 2>`m<&y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^glbxbhI4  
output.writeInt(nStartPos.length); 1h&)I%`?  
for(int i=0;i<nStartPos.length;i++) P=}H1#  
{ zl,bMtQ  
// output.writeLong(nPos); rZb_1E<  
output.writeLong(fileSplitterFetch.nStartPos); l6yB_M
  
output.writeLong(fileSplitterFetch.nEndPos); `W D*Q-&n  
} @m }rQT  
output.close(); 5IwX\  
} `*|LI  
catch(IOException e){e.printStackTrace ();} H@Kl  
catch(Exception e){e.printStackTrace ();} zvWO4\  
} zS,%msT^A  
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//读取保存的下载信息（文件指针位置） \E>%W  
private void read_nPos() tOu90gu  
{ vK[v eFH  
try{ tP/GDC;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); cob9hj#&7  
int nCount = input.readInt(); a-SB1-5jf  
nStartPos = new long[nCount]; {^2({A#&  
nEndPos = new long[nCount]; 4UkP:Vz:  
for(int i=0;i<nStartPos.length;i++) ?Aj\1y4L1  
{ ]JGKL5~p  
nStartPos = input.readLong(); IiYuUN1D  
nEndPos = input.readLong(); e_;%F`  
} '|h./.K  
input.close(); #mi0x06  
} QYFN:XZ  
catch(IOException e){e.printStackTrace ();} *8pe<:A#p  
catch(Exception e){e.printStackTrace ();} =k[(rvU3  
} v3iDh8.__  
(UbR%A|v;  
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private void processErrorCode(int nErrorCode) ./aZ

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{ Q;{D8 #!  
System.err.println("Error Code : " + nErrorCode); 9RbGa Y&  
} :8p2Jxm  
dn:|m^<)  
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//停止文件下载 6i*p +S?U"  
public void siteStop() *m `KU+o-u  
{ Y9\]3Kno  
bStop = true; ROlzs}  
for(int i=0;i<nStartPos.length;i++) 9;m#>a@Y  
fileSplitterFetch.splitterStop(); 
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}
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} VO\S>kw  
//负责部分文件的抓取 #!K~_DL  
**FileSplitterFetch.java jn5=N[hd  
*/ uL qpbn  
package NetFox; oj
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import java.io.*; xKkVSEup  
import java.net.*; KU8Cl>5  
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public class FileSplitterFetch extends Thread { noB}p4  
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String sURL; //File URL PHE;  
long nStartPos; //File Snippet Start Position O23]!S<;  
long nEndPos; //File Snippet End Position kW7&~tX  
int nThreadID; //Thread's ID k~W;TCJs
  
boolean bDownOver = false; //Downing is over 10QNV=yK7s  
boolean bStop = false; //Stop identical */fs.G:P  
FileAccessI fileAccessI = null; //File Access interface v/4X[6(  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @EH4N%fH  
{ Z7k1fv:S^  
this.sURL = sURL; ~Krg8s!F&  
this.nStartPos = nStart; Z_hBd['!  
this.nEndPos = nEnd; 2#Q"@  
nThreadID = id; l[!C-Tq  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 NjCLL`?f  
} FSXKH{Z  
&p(*i@Ms  
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public void run() ?><   
{ $`+~QR!h  
while(nStartPos < nEndPos && !bStop) F".IB^}$  
{ 2EI m  
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try{ JUUF^/J  
URL url = new URL(sURL); Qnu&GBM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c]:J/'vc  
httpConnection.setRequestProperty("User-Agent","NetFox"); c^q O@%s  
String sProperty = "bytes="+nStartPos+"-"; VN55!l'OV  
httpConnection.setRequestProperty("RANGE",sProperty); VS@rM<K{  
Utility.log(sProperty); d}6AHS[  
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InputStream input = httpConnection.getInputStream(); /=O+/)l`  
//logResponseHead(httpConnection); mc[_
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byte[] b = new byte[1024]; J*W;{Vty  
int nRead; ;7hX0AK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) E&Zx]?~  
{ "e!$=;5  
nStartPos += fileAccessI.write(b,0,nRead); ~wd?-$;070  
//if(nThreadID == 1) @"#gO:|[i0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Wb
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} '~vSH9nx/  
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Utility.log("Thread " + nThreadID + " is over!"); f<t*#]<  
bDownOver = true; 2>_LX!kyP]  
//nPos = fileAccessI.write (b,0,nRead); n46PQm%p  
} .4m3@!qo)E  
catch(Exception e){e.printStackTrace ();} )]e d;V  
} 5|B(K @<  
} ]t!}D6p  
'-1jWw:8  
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//打印回应的头信息 2K7:gd8Ru  
public void logResponseHead(HttpURLConnection con) aN);P>
 
{ uEi.nSp)S  
for(int i=1;;i++) &>^Ympr  
{ 8"I5v(TV  
String header=con.getHeaderFieldKey(i); (;S]{z%  
if(header!=null) C Wl95g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9#$V1(}?  
Utility.log(header+" : "+con.getHeaderField(header)); o dQ&0d  
else 0kr& c;~  
break; -*{(#k$  
} y0y;1N'KK  
} ]NhWhJ:  
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public void splitterStop() UBk 5O&  
{ U3R`mHr0  
bStop = true; :|6D@  
} .$E~.6J %i  
8 $*cfOC  
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} rgY?X$1q_  
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/* ~}9H<K3V  
**FileAccess.java {]^%?]e  
*//文件访问(定位，写) sT T455h)  
package NetFox; {xb%P!o`  
import java.io.*; [AOluS  
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public class FileAccessI implements Serializable{
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~$
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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 |k9j )Hg(  
RandomAccessFile oSavedFile; $TW+LWb   
long nPos; G&@RLht  
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public FileAccessI() throws IOException 3<Y;mA=hw  
{ \YF!< 2|[  
this("",0); 5T@'2)BI=  
} f#-T%jqnK  
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public FileAccessI(String sName,long nPos) throws IOException J+*Y)k  
{ ^*~u4
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oSavedFile = new RandomAccessFile(sName,"rw"); _EBDv0s  
this.nPos = nPos; lkJ#$Ik&  
oSavedFile.seek(nPos); Vy"^]5  
} !(AFT!  
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public synchronized int write(byte[] b,int nStart,int nLen) 5v-;*  
{ OMC|.[  
int n = -1; )C0X]?  
try{  l e/#J  
oSavedFile.write(b,nStart,nLen); ?d`+vHK
]>  
n = nLen; Vt2=rD4oJk  
} AS-t][m#  
catch(IOException e) 1OwkLy,P  
{ X#C7r@H  
e.printStackTrace (); X{5DPhB,  
} $GKm`I"  
e
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return n; /XK`v=~(l{  
} w!k4&Rb3  
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} >~8Df61o`  
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/* gMMd=  
**SiteInfoBean.java @+vTGjHA  
*/ Kt7x'5  
package NetFox; Ln -?/[E  
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public class SiteInfoBean { ]xeyXw84k  
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private String sSiteURL; //Site's URL rNO;yL4)ey  
private String sFilePath; //Saved File's Path 8"rX;5 vP  
private String sFileName; //Saved File's Name UR=s{nFd  
private int nSplitter; //Count of Splited Downloading File 'GoeVq  
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public SiteInfoBean() _cs9
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{//nSplitter的缺省值为5 \r9%;?f  
//default value of nSplitter is 5 QQ8W;x  
this("","","",5); k.Nu(j"z  
} i^KYZ4/%  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -$ft `Ih  
{ [\F,\  
sSiteURL= sURL; Ox'.sq4  
sFilePath = sPath; AWNd(B2o  
sFileName = sName; G{Q'N04
RA  
this.nSplitter = nSpiltter; <LZvh8  
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t#  
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} Y%9F  
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 n(1"6  
public String getSSiteURL() &4
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{ &3?yg61Ag  
return sSiteURL; sYgnH:t X  
} )5OU!c  
1dO8[5uM7a  
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public void setSSiteURL(String value) qnRz
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{ $8}'6,  
sSiteURL = value; MF(~!SOIG  
} 3%a37/|~y  
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public String getSFilePath() k| o,gcU  
{ ![tI(TPq  
return sFilePath; v[ '5X  
} JwczE9~o  
rT)R*3  
'E,Yht=/}  
public void setSFilePath(String value) r8.v0b"1  
{ \LXC269  
sFilePath = value; i% lB U1  
} I\23as0q  
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public String getSFileName() B6oAW,3  
{ OK}"|:hrd  
return sFileName; F#wa)XH
 
} z+I-3v  
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public void setSFileName(String value) +rY0/T_0,  
{ 6vA5;a@  
sFileName = value; 7A-rF U$  
} 7mNskb|  
^*Fkt(ida  
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public int getNSplitter() 20)Il:x  
{ #!Fs
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return nSplitter; [\yI<^_
a  
} d:''qgz`  
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public void setNSplitter(int nCount) 7
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{ Hyg?as>}u  
nSplitter = nCount; 1gJ!!SHPo  
} <i|+p1t  
} 9=f'sqIPV  
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/* `-\"p;Hp0  
**Utility.java CcTJCuOS  
*/ 4+gA/<  
package NetFox; Wg1WY}zG  
Y<XDR:]A,  
|93%,  
public class Utility { wP9C\W;  
'=@x2`U/  
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public Utility() 3R><AFMY?  
{ (" %yV_R  
~/%){t/uLY  
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} 'z'm:|JW  
urB.K<5ZA  
//线程睡眠 JGe;$5|q8  
public static void sleep(int nSecond) 2<|5zF  
{ m}(DJ?qP  
try{ G#Ow>NJ  
Thread.sleep(nSecond); 0l6%[U?o  
} ]Y?$[+Y  
catch(Exception e) aRmS{X3  
{ C*!_. <b  
e.printStackTrace (); .Yx.Lm}  
} s@|?N+z  
} ceCshxTU  
%XeU4yg\e  
//日志 uJ$,e5q  
public static void log(String sMsg) z4goa2@Z  
{ G`z48  
System.err.println(sMsg); Su7?-vY  
}  lzuZv$K  
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7d*<'k]{,  
public static void log(int sMsg) "=;&{N~8U  
{ AUK7a  
System.err.println(sMsg); Mi/_hzZ\  
} j; C(:6#J  
} ,3j*D+  
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_
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/* UPC& O  
**TestMethod.java K&*FI (a  
*/ 1jyWP#M#  
package NetFox; r4sR5p]|  
8z-Td-R6  
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public class TestMethod { 0AEs+=  
aZRgd^4  
ol\IT9Zb~  
public TestMethod() S]>_o"|HV  
{ ///xx/weblogic60b2_win.exe \Mi< ROp5  
try{ N?XN$hwdZ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,]MX&]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `@&qf}`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N%a[Y  
fileFetch.start(); lVdExR>H  
} QEPmuG  
catch(Exception e){e.printStackTrace ();} L0Cf@~k  
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} ) l)5^7=W  
jd{J3s '%  
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public static void main(String[] args) @lX)dY  
{ OL>/FOH:Fx  
new TestMethod(); 'e)t+  
} m3D'7*U  
} e.T5F`Du  
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