http断点续传简单实现（java)

/* 877>=Tp|  
**SiteFileFetch.java n8zh;vuJ  
*/ $4V ~hI4  
package NetFox; dG|srgk+  
import java.io.*; !U$ %Jz  
import java.net.*; ~9qDmt,i  
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public class SiteFileFetch extends Thread { 0\AYUa?RM  
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SiteInfoBean siteInfoBean = null; //文件信息Bean I\sCH  
long[] nStartPos; //开始位置 (r,RwWYm  
long[] nEndPos; //结束位置 #jV6w=I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1$f
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long nFileLength; //文件长度 apUV6h-v  
boolean bFirst = true; //是否第一次取文件 mp~\ioI*d  
boolean bStop = false; //停止标志 17G7r\iNYq  
File tmpFile; //文件下载的临时信息 $Q|66/S^  
DataOutputStream output; //输出到文件的输出流 Nuk\8C  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） EOV<|WF>  
public SiteFileFetch(SiteInfoBean bean) throws IOException =o=)EU{~  
{ p/WEQ2  
siteInfoBean = bean; @4_CR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9dw02bY`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ||7r'Q  
if(tmpFile.exists ()) tkWWR%c"  
{ aO'$}rDf$  
bFirst = false; L[+65ce%*  
read_nPos(); t09,X  
} MC3XGnT#5  
else J6Mm=b
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{ tiwhG%?2  
nStartPos = new long[bean.getNSplitter()]; >k^=+  
nEndPos = new long[bean.getNSplitter()]; )zt*am;  
} ^zqz$G#  
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} R\yw9!ESd  
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public void run() 1O9V Ej5  
{ e)\s0#  
//获得文件长度  ~J"*ahl  
//分割文件 GVY_u@6   
//实例FileSplitterFetch ~9]tt\jN*Y  
//启动FileSplitterFetch线程 l4u`R(!n5  
//等待子线程返回 -BACdX  
try{ H"I|dK:  
if(bFirst) u9m"{KnV  
{ 9ZG.%+l  
nFileLength = getFileSize(); xgJ2W_  
if(nFileLength == -1) W;IvR  
{  7P]_03  
System.err.println("File Length is not known!"); ` M"Zq  
} L<QqQ"`  
else if(nFileLength == -2) t ba%L  
{ X>F/0/  
System.err.println("File is not access!"); sBF}j.b  
} ImklM7A  
else yYWGM  
{ Lc*i[J<s  
for(int i=0;i<nStartPos.length;i++) ^'
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{ rtf>\j+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `EU=u_N  
} WABq6q!  
for(int i=0;i<nEndPos.length-1;i++) RhbYDsG  
{ |)pT"`  
nEndPos = nStartPos[i+1]; H*yX Iq:  
} PWL
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nEndPos[nEndPos.length-1] = nFileLength; >F,~QHcz  
} v"_hWJ)  
} &hd+x5  
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//启动子线程 q(!191@C(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7Y@&&  
for(int i=0;i<nStartPos.length;i++) athU  
{ qN+ngk,:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 33[2$FBf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wvJm)Mj+  
nStartPos,nEndPos,i); O,9KhX+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b
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fileSplitterFetch.start(); O>|Q Zd  
} Q?7UiTZ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SMqJMirR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .0.Ha}{6b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", gGe `w  
nEndPos = " + nFileLength); F7
#  
// fileSplitterFetch[nPos.length-1].start(); x1$fkNu  
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//等待子线程结束 vlm&)DIt  
//int count = 0; <G\q/!@_  
//是否结束while循环 O)`R)MQ)  
boolean breakWhile = false; 2
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while(!bStop) ?$pp%  
{ U $X"W'  
write_nPos(); id&;

 
Utility.sleep(500); [)#,~L3  
breakWhile = true; J'b*^K  
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for(int i=0;i<nStartPos.length;i++) y&-j NOKLM  
{ EmVE<kY.  
if(!fileSplitterFetch.bDownOver) "ln(EvW  
{ )@\= pE.H  
breakWhile = false; #G$_\bt  
break; (6>8Dt 9[  
} 5Ee%!Pk  
} \@GA;~x.b  
if(breakWhile) :=T+sT~  
break; &JtK<g  
-+#\WB{AI  
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//count++; C:0Ra^i ?L  
//if(count>4) NK$k9,  
// siteStop(); a
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} o[O-|XL_  
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System.err.println("文件下载结束！"); @i$9c)D  
}
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catch(Exception e){e.printStackTrace ();} 2}/Z.)^Q  
} 'n#;~  
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//获得文件长度 ow>^(>^~  
public long getFileSize()
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{ ZXFM_>y5  
int nFileLength = -1; 506B=  
try{ (XX6M[M8  
URL url = new URL(siteInfoBean.getSSiteURL()); T7'njaLec  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >hJ$~4?  
httpConnection.setRequestProperty("User-Agent","NetFox"); |K,9EM
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int responseCode=httpConnection.getResponseCode(); 0V1)ou84'  
if(responseCode>=400) xw&[ 9}Y  
{ [YpSmEn}Y  
processErrorCode(responseCode); J;Xh{3[vO  
return -2; //-2 represent access is error *[wy- fu  
} cWA9n}Z  
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String sHeader; \rF6"24t6  
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for(int i=1;;i++) p&>*bF,  
{ \A6MVMF8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); q?nXhUD  
//Utility.log(in.readLine()); \j+O |#`|)  
sHeader=httpConnection.getHeaderFieldKey(i); %FDi7Rx  
if(sHeader!=null) +%OINMo.A  
{ _[<R<&jG  
if(sHeader.equals("Content-Length")) ^&03D5@LoY  
{ E3X:{h/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'nz;|6uC  
break; j\B]>PP5  
} osoreo;V^  
} d(3F:dbk  
else X
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break; =;W"Pi;*  
} .0:BgM  
} 3{LXx  
catch(IOException e){e.printStackTrace ();} O#7ONQfBO  
catch(Exception e){e.printStackTrace ();} Hz
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Utility.log(nFileLength); GbFLu`Iu  
: ^F+mQN  
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return nFileLength; AjKP -[  
} x%pC.0%  
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//保存下载信息（文件指针位置） r Lg(J|^  
private void write_nPos() vIF=kKl9,  
{ Sf);j0G,D  
try{ )@09Y_9r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); X^r5su?  
output.writeInt(nStartPos.length); \V  /s  
for(int i=0;i<nStartPos.length;i++) p(QB5at  
{ EgOAEv  
// output.writeLong(nPos); A[oLV"J6x5  
output.writeLong(fileSplitterFetch.nStartPos);
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output.writeLong(fileSplitterFetch.nEndPos); *;"N kCf  
} bY|%ois4  
output.close(); #+N\u*-S  
} bE#=\kf|  
catch(IOException e){e.printStackTrace ();} 1t_$pDF}  
catch(Exception e){e.printStackTrace ();} hb9e6Cc  
} guz{DBlK  
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//读取保存的下载信息（文件指针位置） %C\Q{_AS  
private void read_nPos() QZB2yK3]h  
{ %Koc^ pb)  
try{ 4:q<<vCJv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kMWu%,s4  
int nCount = input.readInt(); bj\v0NKN4  
nStartPos = new long[nCount]; {_0Efc=7  
nEndPos = new long[nCount]; WMnR+?q  
for(int i=0;i<nStartPos.length;i++) S+py\z%  
{ t j&+HC  
nStartPos = input.readLong(); :@jhe8'w  
nEndPos = input.readLong(); SweaERl  
} LTj;e[  
input.close(); fu?5gzT+b  
} nF~</>  
catch(IOException e){e.printStackTrace ();} ,Xs%Cg_Ig  
catch(Exception e){e.printStackTrace ();} vo)
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} 4!p~Mr[E  
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private void processErrorCode(int nErrorCode) .j:.?v  
{ fzO4S^mTo8  
System.err.println("Error Code : " + nErrorCode); AFcsbw  
} CP_ ?DyWU  
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//停止文件下载 k$UgTZ  
public void siteStop() !4GGq  
{ P
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bStop = true; }hrLM[  
for(int i=0;i<nStartPos.length;i++) Bj09?#~[  
fileSplitterFetch.splitterStop(); G;_QE<V~_  
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} `,i'vb`W#b  
} gvvl3`S{  
//负责部分文件的抓取 zvf:*Na")  
**FileSplitterFetch.java ;F9<Yv  
*/ b}S}OW2  
package NetFox; #mlTN3   
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import java.io.*; yn<H^c  
import java.net.*; FL% GW:  
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public class FileSplitterFetch extends Thread { *(Y
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String sURL; //File URL z"*X/T  
long nStartPos; //File Snippet Start Position UZ0fw@RM  
long nEndPos; //File Snippet End Position ;"SnCBt:>  
int nThreadID; //Thread's ID 2|@@x

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boolean bDownOver = false; //Downing is over fI>>w)5  
boolean bStop = false; //Stop identical ?#!Hm`\.  
FileAccessI fileAccessI = null; //File Access interface kKVd4B[#*  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException H1_XEcaM+*  
{ s|rlpd4y  
this.sURL = sURL; (_
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this.nStartPos = nStart; K]' 84
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this.nEndPos = nEnd; p8K4^H  
nThreadID = id; hm3,?FMbq  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 O=LS~&=,  
} 3":ef|w]  
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public void run() F,Y,0f@4U9  
{ VvN52 qeL  
while(nStartPos < nEndPos && !bStop) <$wh@$PK  
{ ATCFdtNc  
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try{ \}xK$$f2,  
URL url = new URL(sURL); I"Y d6M% ;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F+PIZ%  
httpConnection.setRequestProperty("User-Agent","NetFox"); _a@&$NEox  
String sProperty = "bytes="+nStartPos+"-"; (rO_Vfaa  
httpConnection.setRequestProperty("RANGE",sProperty); F>jPr8&
  
Utility.log(sProperty); ~t[#p:  

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InputStream input = httpConnection.getInputStream(); B!GpD@U  
//logResponseHead(httpConnection); F{)YdqQ  
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byte[] b = new byte[1024]; &?>h#H222  
int nRead; K];nM}<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O-Hu:KuIf  
{ I\DmVc\l  
nStartPos += fileAccessI.write(b,0,nRead); T:o!H Xdj^  
//if(nThreadID == 1) :zfnp,Gv  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v#&r3ZW0  
} _ _cJ+%e  
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Utility.log("Thread " + nThreadID + " is over!"); B04%4N.g"X  
bDownOver = true; %41dVnWB^4  
//nPos = fileAccessI.write (b,0,nRead); 6l&m+!i  
} mj5$ 2J  
catch(Exception e){e.printStackTrace ();} Ol H{!  
} c+?L?s`"  
} },'hhj]O  
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//打印回应的头信息 #Z<pks2 y  
public void logResponseHead(HttpURLConnection con) D 7 l&L  
{ L>+g;GJ  
for(int i=1;;i++) &;L4Cj$q  
{ }MP2)6  
String header=con.getHeaderFieldKey(i); FP<RoA?W  
if(header!=null) KJWYG^zI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); l=D E|:  
Utility.log(header+" : "+con.getHeaderField(header)); 2uFaAAT  
else DR3M|4[  
break; fl _k5Q'&p  
} hnZI{2XzBE  
} Ntr5Q IPd  
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public void splitterStop() N[X%tf\L]F  
{ rg+28tlDn  
bStop = true; S!.aBAW  
} #n%?}  
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} $_ub.g|  
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/* '&Ox,i]t  
**FileAccess.java F7a &-  
*//文件访问(定位，写) yq+<pfaqvK  
package NetFox; }l$M%Ps!a  
import java.io.*; 'D%No
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public class FileAccessI implements Serializable{ &b,.W;+  
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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 $UW!tg*U&  
RandomAccessFile oSavedFile; heoOOP(#  
long nPos; SFoF]U09
 
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public FileAccessI() throws IOException "BjQs<]%sF  
{ r4t|T^{sl  
this("",0); Z)'jn8?P  
} !_E E|#`n  
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public FileAccessI(String sName,long nPos) throws IOException ?15k~1nA  
{ /b6Y~YbgU  
oSavedFile = new RandomAccessFile(sName,"rw"); eHK}U+"\  
this.nPos = nPos; ^!k^=ST1J  
oSavedFile.seek(nPos); ehCc N4V(  
} seY0"ym&e  
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public synchronized int write(byte[] b,int nStart,int nLen) yd"|HHx  
{ $m:}{:LDCf  
int n = -1; J9ovy>G  
try{ p9R`hgx  
oSavedFile.write(b,nStart,nLen); ]n?a h  
n = nLen;  wJ!  
} S$W *i@x?  
catch(IOException e) +A W6 >yV`  
{ a$#,'UB  
e.printStackTrace (); OQ#gQ6;?
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} ~]Mq
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return n; COv#dOw  
} %#Wg>6  
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} Fdd$Bl.&XS  
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/* z QoMHFL3  
**SiteInfoBean.java Xfx(X4$9  
*/ }@@1N3nnxV  
package NetFox; eC9~ wc  
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public class SiteInfoBean { GEA@AD=^f  
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private String sSiteURL; //Site's URL vtR<(tOu@  
private String sFilePath; //Saved File's Path <y*#[:i  
private String sFileName; //Saved File's Name 8/b_4!5c  
private int nSplitter; //Count of Splited Downloading File 0'^? m$  
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public SiteInfoBean() )
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{//nSplitter的缺省值为5 *bn9j>|iv  
//default value of nSplitter is 5 A42At]  
this("","","",5); \_@u"+,$W  
} =%Ut&6}sQ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mwbkXy;8  
{ .^@+$}   
sSiteURL= sURL; WSDNTfpI  
sFilePath = sPath; 4TG|  
sFileName = sName; dyWWgC%A  
this.nSplitter = nSpiltter; )t&|oQ3sVG  
~
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} b_V)]>v+  
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public String getSSiteURL() RfN5X}&A  
{ 'ZT!a]4  
return sSiteURL; dq:M!F  
} .%->  
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public void setSSiteURL(String value) U{>!`RN  
{ m{%_5nW  
sSiteURL = value; 5`x9+XvoN  
} A ,LAA$  
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public String getSFilePath() L8bq3Q'p  
{ "%f>/k;!h.  
return sFilePath; OFRzzG@  
} k%In   
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public void setSFilePath(String value) H:[z#f|t  
{ 3J'a  
sFilePath = value; Y#]Y$n  
} W:rzfO.`Z  
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C 2oll-kN  
public String getSFileName() ^D.B^BR  
{ !+>yCy$~_  
return sFileName; -vjjcyTt  
} B]*&lRR  
y]?$zbB  
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public void setSFileName(String value) J8b]*2D  
{ 6_XX[.%  
sFileName = value; <5$= Ta  
} <NJ7mR}  
L~mL9[(,  
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public int getNSplitter() VwC,+B  
{ jC\R8_  
return nSplitter; ^<% w'*gR  
} uxh4nyE  
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public void setNSplitter(int nCount) Ok:@F/ v  
{ DJn>. Gd  
nSplitter = nCount; V9<[v?.\  
} 7#g C(&\A  
} F`u{'w:Hv  
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/* ;<&s_C3  
**Utility.java Tu6he8Q-  
*/ p!Gf^  
package NetFox; ?` `+OH  
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public class Utility { D 'u+3  
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public Utility() L7jz^g^  
{ 5;|9bWH  
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} )(ma  
Gf%o|kX]  
//线程睡眠 `8y &  
public static void sleep(int nSecond) k~vmHb
 
{ Gg;#U`  
try{ KB
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Thread.sleep(nSecond); P' J_:\  
} Y]Fq)-  
catch(Exception e) !^m
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{ _nRshTt`V&  
e.printStackTrace (); M>]%Iu  
} \JyWKET::_  
} gai?LXM l}  

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//日志 /=3g-$o{`  
public static void log(String sMsg) Ha/\&Z(  
{ q7)$WXe2LM  
System.err.println(sMsg); _ssHRbE  
} NeK:[Q@je  
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#dl8+  
public static void log(int sMsg) ow$#kQ&R O  
{ @O3
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System.err.println(sMsg); w_{z"VeD  
} 7}lZa~/  
} NMj`wQ`M+  
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/f6]XP\'`+  
/* >WD^)W fa  
**TestMethod.java I{Kc{MXn  
*/ z)]EB6uRg  
package NetFox; Ke/P[fo  
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public class TestMethod { '|q:h  
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public TestMethod() JA)gM  
{ ///xx/weblogic60b2_win.exe [n}c}%  
try{ lZua"Ju  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); c]"B)I1L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ( ou:"Y  
SiteFileFetch fileFetch = new SiteFileFetch(bean); sXydMk`J  
fileFetch.start(); Pw7'6W1  
} YVaQ3o|!  
catch(Exception e){e.printStackTrace ();} &t8_J3?Z  
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} \LYQZ*F  
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public static void main(String[] args) y,
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{ ,,Db:4qfjD  
new TestMethod(); U'lD|R,g  
} ,yqzk.  
} 0F3>kp4u  
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