http断点续传简单实现（java)

/* 1J{fXh  
**SiteFileFetch.java z.oU4c
 
*/ &Z;_TN
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package NetFox; W:`#% :C  
import java.io.*; @gY\;[#.  
import java.net.*; Eectxyr?;N  
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public class SiteFileFetch extends Thread { ]$A(9Pn"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean v.&>Ih/L
 
long[] nStartPos; //开始位置 GZ3 ]N  
long[] nEndPos; //结束位置 /,s[#J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }Fa%%}  
long nFileLength; //文件长度 J?&l*_m;t  
boolean bFirst = true; //是否第一次取文件 5~H#(d<oZ  
boolean bStop = false; //停止标志 ZmEEj-*7s  
File tmpFile; //文件下载的临时信息 DyO$P#~?  
DataOutputStream output; //输出到文件的输出流 7 oQ[FdRn*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9GU]l7C=z  
public SiteFileFetch(SiteInfoBean bean) throws IOException =*Z5!W'd  
{ 4!.(|h@  
siteInfoBean = bean; H8{ol6wc)6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]:ZdV9`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); upy\gkpnGO  
if(tmpFile.exists ()) i7*EbaYzUO  
{ 4J0Rvod_  
bFirst = false; #Sh <Ih  
read_nPos(); zMi; A6  
} <S?#@F\"S  
else [?k8}B)mHB  
{ i-" p)2d=#  
nStartPos = new long[bean.getNSplitter()]; *\G)z|^yx  
nEndPos = new long[bean.getNSplitter()]; }ns-W3B'  
} (R!hjw~  
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} CGbwm
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public void run() LR(-<"  
{ NZ0O,}m  
//获得文件长度 5PT5#[  
//分割文件 Q~{H@D`<  
//实例FileSplitterFetch -7 U|a/  
//启动FileSplitterFetch线程 oczG|_  
//等待子线程返回 !C4!LZ0A  
try{ X;oa[!k  
if(bFirst) 9$qm
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{ ?9{~> 4@
 
nFileLength = getFileSize(); _)T5lEFl=  
if(nFileLength == -1) ml`8HXK0  
{ #OO>rm$  
System.err.println("File Length is not known!"); <h-vjz  
} A/7{oB:a  
else if(nFileLength == -2) ,Wbwg  
{ 7!WA)@6  
System.err.println("File is not access!"); cyyVg!+  
} 7&qy5y-Ap  
else 6!'3oN{  
{ (QoI<j""  
for(int i=0;i<nStartPos.length;i++) ZyrI R  
{ (xHf4[[u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9
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} %a+mk E  
for(int i=0;i<nEndPos.length-1;i++) VHJM*&5  
{ Gs+3
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nEndPos = nStartPos[i+1]; },+wJ1  
} ,'xYlH3s  
nEndPos[nEndPos.length-1] = nFileLength; hCjR&ZA  
} L>yJ  
} &|3 $!S  
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//启动子线程 ojvj}ln  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; '(bgs  
for(int i=0;i<nStartPos.length;i++) I M-L'9  
{ (3J$>Na  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ydRC1~f0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nD5 gP  
nStartPos,nEndPos,i); ?=m?jNa;nC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tg]x0#@s  
fileSplitterFetch.start(); 26&'X+n&  
} &0 >Loja`^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s7Ub@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6f')6X'x  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "j;4 k.`h  
nEndPos = " + nFileLength); )M6w5g  
// fileSplitterFetch[nPos.length-1].start(); Q8!)!r%  
={K`4BD  

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//等待子线程结束 Tq]Sn]CSP  
//int count = 0; 1$M@]7e+!+  
//是否结束while循环 wr[,  
boolean breakWhile = false; \b%kf99  
^6_e=jIN  
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while(!bStop) ):i&`}SY  
{ CC#;c1t  
write_nPos(); BZzrRC  
Utility.sleep(500); ~HOy:1QhE=  
breakWhile = true; Ec
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for(int i=0;i<nStartPos.length;i++) 9E>xIJ@J2T  
{ u%w`:v7Yo(  
if(!fileSplitterFetch.bDownOver) {&jb5-*f  
{ ne4Q#P  
breakWhile = false; M$Zcn#A  
break; D6>HN
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} T:5fc2Ngv  
} b0lq\9  
if(breakWhile) $2W%2rZ  
break; >-H{Z{VDd  
:xtXQza"-  
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//count++; N5a*7EJv+  
//if(count>4) G6T_O  
// siteStop(); xuqv6b.  
} NR`C(^}  
{zMU#=EC  
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System.err.println("文件下载结束！"); ;kY(<{2  
} &*+'>UEe5  
catch(Exception e){e.printStackTrace ();} `DV.+>O-1  
} C?
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//获得文件长度 /Mvf8v  
public long getFileSize() !\7!3$w'8,  
{ eEuvl`&  
int nFileLength = -1;  Vh_P/C+  
try{ i\,-oO  
URL url = new URL(siteInfoBean.getSSiteURL()); +j< p \Kn>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,6-:VIHQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); Wk)OkIFR  
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int responseCode=httpConnection.getResponseCode(); *MKO I'  
if(responseCode>=400) IZpP[hov  
{ G"h'_7  
processErrorCode(responseCode); 03q5e  
return -2; //-2 represent access is error < jJ  
} OX\A|$GS  
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String sHeader; wB.&}p9p  
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k?+?v?I =  
for(int i=1;;i++) be.*#[  
{ E=nIRG|g  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); s.$3j$vT 8  
//Utility.log(in.readLine()); sS*3=Yh  
sHeader=httpConnection.getHeaderFieldKey(i); ;U-jO &  
if(sHeader!=null) 5>[u `  
{ Z&1\{PG3*  
if(sHeader.equals("Content-Length")) qm/)ku0  
{ .+$Q<L  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'Gj3:-xqL  
break; 9Z4nAc
 
} M/b Sud?@%  
} a<^v(r  
else ~E17L]ete  
break; 3LOdjT J  
} yDzc<p\`  
} LRL,m_gt  
catch(IOException e){e.printStackTrace ();} }
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catch(Exception e){e.printStackTrace ();} pFOx>u2`a  
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Utility.log(nFileLength); G?O1>?4C  
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return nFileLength; T&6l$1J  
} 8A##\j)  
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//保存下载信息（文件指针位置） CsGx@\jN  
private void write_nPos() bCRV\myd`  
{ ,E S0NA  
try{ C5o#i*|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Y]'Z7<U}*E  
output.writeInt(nStartPos.length); Va"0>KX  
for(int i=0;i<nStartPos.length;i++) *4\:8  
{ ;U/&I3dzV  
// output.writeLong(nPos); !fE`4<|?  
output.writeLong(fileSplitterFetch.nStartPos); "\:`/k3  
output.writeLong(fileSplitterFetch.nEndPos); +r2+X:#~T  
} ]d$8f  
output.close(); >mwlsL~X  
} e"{{ TcNk  
catch(IOException e){e.printStackTrace ();} hOjk3 k  
catch(Exception e){e.printStackTrace ();} j#!IuH\]  
} $V-~Bu-  
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//读取保存的下载信息（文件指针位置） f%][}NN)Xr  
private void read_nPos() 3lrT3a3vV  
{ 11Q1AN  
try{ 0CnOL!3.I  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @0Ic3C[rH6  
int nCount = input.readInt(); Ni9/}bb  
nStartPos = new long[nCount]; <? q?Mn  
nEndPos = new long[nCount]; ?WGA?J %2  
for(int i=0;i<nStartPos.length;i++) %~4M+r6T  
{ -_=nDH  
nStartPos = input.readLong(); ,LHn90S  
nEndPos = input.readLong(); 3c-GY:VkLM  
} <sb~ ^B  
input.close(); }bb;~  
}
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catch(IOException e){e.printStackTrace ();} Acez'@z  
catch(Exception e){e.printStackTrace ();} $*^7iT4q_t  
} G/)O@Ugp  
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private void processErrorCode(int nErrorCode) 03$mYS_?  
{ 9}rS(/@ }  
System.err.println("Error Code : " + nErrorCode); 5T
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} ejS
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9 P
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//停止文件下载 Dj"F\j 1  
public void siteStop() Wf+cDpK  
{ $0W|26;  
bStop = true; g2+2%6m0  
for(int i=0;i<nStartPos.length;i++) Cj
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fileSplitterFetch.splitterStop(); h79}qU  
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} 5AFJC?  
} is?{MJZ_  
//负责部分文件的抓取 .YtKS  
**FileSplitterFetch.java w'>pY  
*/ R$R*'l  
package NetFox; !z\h|wU+  
m+=] m_  
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import java.io.*; {5Q!Y&N.%  
import java.net.*; owVX*&b{  
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public class FileSplitterFetch extends Thread { g@d*\ P)  
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9)l$ aBa  
String sURL; //File URL tHU2/V:R  
long nStartPos; //File Snippet Start Position .yoH/2h  
long nEndPos; //File Snippet End Position O%\*@4zM  
int nThreadID; //Thread's ID jk;j2YNPw  
boolean bDownOver = false; //Downing is over P0;n9>g  
boolean bStop = false; //Stop identical /p/]t,-j2  
FileAccessI fileAccessI = null; //File Access interface |Tv#4st  
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* `JYC  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException z0d.J1VW  
{ 34f?6K1c  
this.sURL = sURL; *IB4[6  
this.nStartPos = nStart; D(~U6SR  
this.nEndPos = nEnd; D,k6$`  
nThreadID = id; ]=\].% >  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H%[eV8  
} C"y(5U)d  
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public void run() })'B<vq  
{ ,V7nzhA2  
while(nStartPos < nEndPos && !bStop) M`0V~P`^  
{ %aP!hy  
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try{ A[B<~  
URL url = new URL(sURL); &5>Kl}7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !hm]fh_j  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0Fq} N  
String sProperty = "bytes="+nStartPos+"-"; :a!^
  
httpConnection.setRequestProperty("RANGE",sProperty); ,<.V7(|t)  
Utility.log(sProperty); P?%s #I:  
D ;RiGW4  
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InputStream input = httpConnection.getInputStream(); |NlO7aQ>2H  
//logResponseHead(httpConnection); ~?l | [  
+V2F#fI/  
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byte[] b = new byte[1024]; (|2t#'m  
int nRead; C2!|OQ9A2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) n3WlZ!$  
{ aHD]k8m z  
nStartPos += fileAccessI.write(b,0,nRead); r-,
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//if(nThreadID == 1) <]ox;-56  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !M(xG%M-V  
} [DuttFX^x  
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Utility.log("Thread " + nThreadID + " is over!"); EAUEQk?9  
bDownOver = true; YqscZ(L:y  
//nPos = fileAccessI.write (b,0,nRead); h0EEpL|\  
} j/DzCcp7  
catch(Exception e){e.printStackTrace ();} )+#` CIv  
} ]U+LJOb  
} p:&8sO!m  
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//打印回应的头信息 *tA1az-jO  
public void logResponseHead(HttpURLConnection con) a .#)G[*  
{ :@Pl pFK  
for(int i=1;;i++) Q3'llOx  
{ +w`2kv  
String header=con.getHeaderFieldKey(i); w?L6!)oiz  
if(header!=null)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); #<fRE"v:Q  
Utility.log(header+" : "+con.getHeaderField(header)); p%ki>p )E|  
else gt)I(  
break; g>%o #P7  
} 8]c2r%J  
} JtE M,tK  
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public void splitterStop()  1~gnc|?  
{ l$KA)xbI  
bStop = true; <)Dj9' _J  
} X0HZH?V+  
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} hgG9m[?K  
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/* 2k~l$p>CN!  
**FileAccess.java SO/c}vnBB  
*//文件访问(定位，写) AYBns]!  
package NetFox; #^0R&) T
 
import java.io.*; !)f\%lb  
.^`{1%  
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public class FileAccessI implements Serializable{ jVe1b1rt~3  
bL`TySX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 LENq_@$  
RandomAccessFile oSavedFile; Pm6pv;WK  
long nPos; DeVv4D:}@  
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public FileAccessI() throws IOException ,&A7iO  
{ 7~h<$8Y(T  
this("",0); P;.W+WN  
} <dWv?<o  
+HpA:]#Y  
 tU5zF.%  
public FileAccessI(String sName,long nPos) throws IOException 'ZF{R3Xu  
{ 4i;{!sT  
oSavedFile = new RandomAccessFile(sName,"rw"); Wtd/=gmiI  
this.nPos = nPos; 1ba~SHi  
oSavedFile.seek(nPos); 5DU6rks%
 
} =j_4S<  
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1t~G|zhX  
public synchronized int write(byte[] b,int nStart,int nLen) n+9=1Oo"  
{ *8A  
int n = -1; h+H%?:FX  
try{ >h9IM$2  
oSavedFile.write(b,nStart,nLen); )AtD}HEv  
n = nLen; !?jrf] A@  
} M] %?>G  
catch(IOException e) KK4`l}Fk:n  
{ O`kl\K*R7  
e.printStackTrace (); O/(`S<iip  
} }"H,h)T  
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return n; net@j#}j-  
}
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} 79j+vH!zh  
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/* 05#1w#i  
**SiteInfoBean.java Mj3A5;#  
*/ h2A <"w  
package NetFox;  qA7>vi%  
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K7B/s9/xs  
public class SiteInfoBean { |Zpfq63W  
*;slV3  
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private String sSiteURL; //Site's URL M/'sl;  
private String sFilePath; //Saved File's Path [
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private String sFileName; //Saved File's Name wmL'F:UP  
private int nSplitter; //Count of Splited Downloading File
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public SiteInfoBean() ua$GNm  
{//nSplitter的缺省值为5 x+:UN'
"r  
//default value of nSplitter is 5 mDABH@R  
this("","","",5); =o(5_S.u;  
} 9&2O9Nz6  
t|\%VC  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) dL 1tl  
{ 4[r0G+  
sSiteURL= sURL; myQagqRx  
sFilePath = sPath; ~H_/zK6e  
sFileName = sName; nNV'O(x}  
this.nSplitter = nSpiltter; dq6m>;`  
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}eU*( }<^  
} ~ 'cmSiz-  
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^zmG0EH,  
public String getSSiteURL() <c-=3}=U\  
{ %@aS
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return sSiteURL; "Yv_B3p   
} .V/Rfq  
.G
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#U4F0BdA  
public void setSSiteURL(String value) Gr'  CtO  
{ bHYy}weZ  
sSiteURL = value; X/!o\yyT  
} nwe*BVp  
85$m[+md  
dr}`H,X"3  
public String getSFilePath() x,+{9  
{ |bHelD|  
return sFilePath; -UEZ#Q  
} TDKki(o=~  
BLdvyVFx  
/ }X1W  
public void setSFilePath(String value) #aJ(m&  
{ 81F/G5  
sFilePath = value; ;(/ZO%h  
} u;"TTN  
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U^%Q}'UYym  
public String getSFileName() \;3~a9q%  
{ jl$ece5v  
return sFileName; A]0 St@  
} K~{$oD7!  
o3^l~iT  
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public void setSFileName(String value) :yr+vcD?  
{ Ad8n<zt|  
sFileName = value; wLH>:yKUU  
} bKY7/w<dP  
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public int getNSplitter() ZRB)uA)5=  
{ nI-w}NQ  
return nSplitter; g"DG]/ev  
} *boR`[Ond  
mt{nm[D!Xp  
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public void setNSplitter(int nCount) gMmaK0uhS  
{ -t'jNR'  
nSplitter = nCount; Y'S%O/$  
} -q1??u  
} @Z %ivR:  
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/* '&tG?gb&  
**Utility.java zuad~%D<I  
*/ 85:=4N%  
package NetFox; XbKYiy  
r&JgLC(   
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public class Utility { u(>^3PJ+  
p!7FpxZY  
!qh]6%l  
public Utility() ,{u yG
:  
{ <I\/n<*  
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nbD*x|  
} 3vN_p$  
^R7lom.  
//线程睡眠 rdP[<Y9  
public static void sleep(int nSecond) 4{U T!WIi  
{ gjwn7_  
try{ ^e_hLX\SW  
Thread.sleep(nSecond); x7&B$.>3  
} wr/"yQA]  
catch(Exception e) H?vdr:WlTN  
{ FEz-+X<q2  
e.printStackTrace (); 3*"WG O5  
} {0wIR_dGX  
} t
;}|t
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e "4 ''/  
//日志 \5:i;AE  
public static void log(String sMsg)  5h=}j  
{ %~H-)_d20  
System.err.println(sMsg); DFB@O|JL  
} a`E#F]Z  
qs6]-  
p Z|V 3  
public static void log(int sMsg) x_N'TjS^{  
{ (l~AV9!m:  
System.err.println(sMsg); RUnSCOdX  
} _?m(V=z>  
} Eex~xiiV  
x:NY\._  
0WW2i{7`U  
/* z,[Hli*0  
**TestMethod.java [I,Z2G,Jb  
*/ QC OM_$y  
package NetFox; {tuYs:  
A 
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2/\r)$ 2i  
public class TestMethod { Ar
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~F|+o}a`  
BQE|8g'&T  
public TestMethod() l|JE#  
{ ///xx/weblogic60b2_win.exe 'j8:vq^
d  
try{ u"cV%(#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *eTqVG.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X"|['t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); '6iEMg&3  
fileFetch.start(); P6'1.R  
} JW83Tp8[8  
catch(Exception e){e.printStackTrace ();} ,F8Yn5h  
gZ3u=uME  
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} r"3=44St  
Pe_W;q.  
wtQ++l%{G  
public static void main(String[] args) \R9(x]nZ%  
{ shy-Gu&  
new TestMethod(); v!-/&}W)1  
} 36&e.3/#  
} 1Ti f{i,B  
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