http断点续传简单实现（java)

/* +pq=i  
**SiteFileFetch.java D]iyr>V6'  
*/ Z:h'kgG&  
package NetFox; #B?lU"f8q^  
import java.io.*; j-J/yhWO&  
import java.net.*; C3=0st$  
 ) 4t%?wT  
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public class SiteFileFetch extends Thread { cy6YajOk7  
9 AD*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Y]6dYq{k  
long[] nStartPos; //开始位置 cCiDe`T\F  
long[] nEndPos; //结束位置 t3.;qDy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \25EI]  
long nFileLength; //文件长度 :&&s*_  
boolean bFirst = true; //是否第一次取文件 5,4"
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boolean bStop = false; //停止标志 GBS+ 4xL|  
File tmpFile; //文件下载的临时信息 7R5ebMW V  
DataOutputStream output; //输出到文件的输出流 *\:sHVyG(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `j
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public SiteFileFetch(SiteInfoBean bean) throws IOException |AExaO"jk  
{ k fY;  
siteInfoBean = bean; 3jfAv@I~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wU'+4N".  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); J=kf KQV  
if(tmpFile.exists ()) fA1{-JzV<4  
{ VPO~veQ  
bFirst = false; PQ_A^95  
read_nPos(); AwuhFPG  
} w#BT/6
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else ODRy  
{ S/eplz;  
nStartPos = new long[bean.getNSplitter()]; -0`
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nEndPos = new long[bean.getNSplitter()]; er BerbEEH  
} Yevd h<  
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} "tJ[M  
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public void run() #d<"Ub
 
{ 1\lZ&KX$i  
//获得文件长度 <i
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//分割文件 By[M|4a  
//实例FileSplitterFetch 5(1c?biP&  
//启动FileSplitterFetch线程 :>ca).cjac  
//等待子线程返回 b O}&i3.L;  
try{ +,7vbs3  
if(bFirst) _I,GH{lhI  
{ l%0-W  
nFileLength = getFileSize(); c*<BU6y  
if(nFileLength == -1) "ig)7X+Wz|  
{ ~A%+oa*2~  
System.err.println("File Length is not known!"); ?c"iV  
} ^g2Vz4u  
else if(nFileLength == -2) ]NW_oRH  
{ Hv' OO@z  
System.err.println("File is not access!"); +S#Xm4  
} XCxxm3t  
else D8*6h)~  
{ }=|{"C  
for(int i=0;i<nStartPos.length;i++) /VEK<.,aMv  
{ Y HS/|-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >^,?0HP  
} gCRPaF6  
for(int i=0;i<nEndPos.length-1;i++) ;2?fz@KZ  
{ XCyb[(4  
nEndPos = nStartPos[i+1]; m#_M"B.cm  
} &>Z;>6J,  
nEndPos[nEndPos.length-1] = nFileLength; [\fwn
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} E}0g  
} 1jBIi  
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Z
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//启动子线程 iW9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5TeGdfu @  
for(int i=0;i<nStartPos.length;i++) rkdA4'66w  
{ M djxTr^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N<KsQsy=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `|92!Ej  
nStartPos,nEndPos,i); ;1_3E2E$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Fwvc+ a  
fileSplitterFetch.start(); Tk 'Pv  
} 9G7Brs:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Bz%wV-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m9c`"!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $Dv5TUKw  
nEndPos = " + nFileLength); 9`H4"H>yG  
// fileSplitterFetch[nPos.length-1].start(); tblduiN   
# eFdu  
ESFJN}Q%0.  
//等待子线程结束 K,PN:  
//int count = 0; oRg,oy  
//是否结束while循环 p7izy$Wc  
boolean breakWhile = false; f"AT@Ga]  
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while(!bStop) Jko=E   
{ p*1B*R  
write_nPos(); R S>qP;V*-  
Utility.sleep(500); 4OAR["f  
breakWhile = true;  O^
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for(int i=0;i<nStartPos.length;i++) nLANWQk9  
{ w|0
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if(!fileSplitterFetch.bDownOver) "HH<5
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{ !`W0;0'Zg  
breakWhile = false; c|k(_#\B  
break; Ff =%eg]  
} VKlC`k8L  
} 7GErh,  
if(breakWhile) `6#s+JA[  
break; VH+3o?nrT  
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//count++; E1w8d4P,G  
//if(count>4) |S<!'rY  
// siteStop(); gg#lI|  
} ~oK0k_{~  
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System.err.println("文件下载结束！"); )>"Ky  
} s bR*[2  
catch(Exception e){e.printStackTrace ();} .SSyW
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} |]Hr"saO0  
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//获得文件长度 N K@6U_/W  
public long getFileSize() TnKOr~@*  
{ hOFvM&$  
int nFileLength = -1; Yu
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try{ }!|$;3t+c  
URL url = new URL(siteInfoBean.getSSiteURL()); >@-.rkd(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); hl)jE 06  
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int responseCode=httpConnection.getResponseCode(); A9J{>f  
if(responseCode>=400) ]F;1l3I-  
{ \F+".X#jh  
processErrorCode(responseCode); Ul 85-p  
return -2; //-2 represent access is error /L|x3RHs  
} TT#V'r\  
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lh XD9ed  
String sHeader; Tfv@oPu  
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for(int i=1;;i++) $ )2zz>4  
{ SD@ 0X[  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?=-/5A4K  
//Utility.log(in.readLine()); fwUF5Y  
sHeader=httpConnection.getHeaderFieldKey(i); )!G
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if(sHeader!=null) z?UEn#E2
 
{ nhZ/^`Y<  
if(sHeader.equals("Content-Length")) PTXS8e4  
{ /_8nZVu  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m?8o\|i,  
break; ;l < amB  
} *o(bB!q"c  
} g1l:k1\Ht  
else G$CSZrP.  
break; Q
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} !u4eI0?R?  
} t.bM]QU!1  
catch(IOException e){e.printStackTrace ();} ?hURNlR_Q  
catch(Exception e){e.printStackTrace ();} *7L1SjZw  
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Utility.log(nFileLength); /,$V/q+  
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return nFileLength; muFWFq&yP  
} iHQ$L# 7  
}
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*#?9@0b@  
//保存下载信息（文件指针位置） EW`WFBjj  
private void write_nPos() -0NkAQrg  
{ [I<J6=  
try{ >dwWqcP  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Lso%1M  
output.writeInt(nStartPos.length); mW,b#'hy  
for(int i=0;i<nStartPos.length;i++) Aq>?G+  
{ /h]ru SI  
// output.writeLong(nPos); iorQ/(  
output.writeLong(fileSplitterFetch.nStartPos); <KoOJMx(  
output.writeLong(fileSplitterFetch.nEndPos); [W3sveqj&  
} tk:G6Bkid  
output.close(); `ah"Q;d$  
} ztp2j%'  
catch(IOException e){e.printStackTrace ();} @s,kx.S  
catch(Exception e){e.printStackTrace ();} ''z]o#=^9  
} ;!3: 3;  
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//读取保存的下载信息（文件指针位置） [ThAvQ_$  
private void read_nPos() L E
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{ xv%]g=Q  
try{ GE!p  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); W}%[i+  
int nCount = input.readInt(); 6%wlz%Fp  
nStartPos = new long[nCount]; "t-9q  
nEndPos = new long[nCount]; W!+=`[Ff  
for(int i=0;i<nStartPos.length;i++) ;Uy}(  
{ r-]%R:U*  
nStartPos = input.readLong(); w:=:D=xH2  
nEndPos = input.readLong(); 6 Pdao{P  
} q{f (T\  
input.close(); rD !GEU
 
} 2{oQ  
catch(IOException e){e.printStackTrace ();} oMoco tQ;$  
catch(Exception e){e.printStackTrace ();} O]!o|w(  
} 'UuHyC2Ha3  
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private void processErrorCode(int nErrorCode) <P]%{msGH  
{ O+[s4]  
System.err.println("Error Code : " + nErrorCode); _U^G*EqL*  
} vCOtED*<  
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//停止文件下载 ,,ML^ey  
public void siteStop() _C|j"f/}  
{ KYz@H#M  
bStop = true; g{kjd2  
for(int i=0;i<nStartPos.length;i++) 7fl{<uf  
fileSplitterFetch.splitterStop(); s={IKU&m[  
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} @_ UI;*V  
} la^K|!|  
//负责部分文件的抓取 M.EL^;r  
**FileSplitterFetch.java nD!t*P  
*/ K@:t6  
package NetFox; ]xbMMax  
pP#|: %  
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import java.io.*; kD)]\  
import java.net.*; )Z\Zw~L  
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public class FileSplitterFetch extends Thread { -q&,7'V  
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ni<\AF]`  
String sURL; //File URL 8u1?\SYnb  
long nStartPos; //File Snippet Start Position <vxTfE@>bp  
long nEndPos; //File Snippet End Position }2Y`Lr  
int nThreadID; //Thread's ID (''w$qq"D  
boolean bDownOver = false; //Downing is over 7=qvu&{  
boolean bStop = false; //Stop identical VM;vLUu!e  
FileAccessI fileAccessI = null; //File Access interface 3[ xHY@c  
/R>YDout}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ' hdLQ\J  
{ 3bQq Nk  
this.sURL = sURL; 5FsfJpw  
this.nStartPos = nStart; AWAJ*6Z  
this.nEndPos = nEnd; g?cxqC<  
nThreadID = id; )a%E $`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <KE%|6oER  
} K;>9K'n  
jBd=!4n  
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public void run() k$kxw_N5d  
{ 5Z=GFKf|  
while(nStartPos < nEndPos && !bStop) 
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{ _c(h{dn  
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try{ E*s _Y  
URL url = new URL(sURL); Zt9ld=T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8m[o*E.4F  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]]y,FQ,r  
String sProperty = "bytes="+nStartPos+"-"; _G2)=yj]  
httpConnection.setRequestProperty("RANGE",sProperty); xP27j_*m>  
Utility.log(sProperty); $-s8tc(  
/wkrfYRs  
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InputStream input = httpConnection.getInputStream(); O:imX>|u  
//logResponseHead(httpConnection); i8%@4U/ J  
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byte[] b = new byte[1024]; V=YDqof  
int nRead; gN*b~&G  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {xICR ~,*  
{ l j+p}dt  
nStartPos += fileAccessI.write(b,0,nRead); k"m+i  
//if(nThreadID == 1) t%@u)bp  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Zb'a+8[  
} H;ujB \+  
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Utility.log("Thread " + nThreadID + " is over!"); }?HWUAL\  
bDownOver = true; A-rj: k!  
//nPos = fileAccessI.write (b,0,nRead); ,-DU)&dF  
} !\'HKk~V  
catch(Exception e){e.printStackTrace ();} xl,6O!aR  
} Y@ vC!C  
} ~aXJ5sY"f&  
,F+,A].wG  
-M4VC^_  
//打印回应的头信息 Tr;&bX5]H  
public void logResponseHead(HttpURLConnection con) \!%~(FM  
{ $I<\Yuy-M9  
for(int i=1;;i++) h8;H<Y;yQ  
{ Pu'NSNT  
String header=con.getHeaderFieldKey(i); d@tNlFfS  
if(header!=null) Q!I><u  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); j(M.7Z7^  
Utility.log(header+" : "+con.getHeaderField(header));  @l&{ j  
else }Nma %6PfV  
break; EoS6t  
} g!)*CP#;  
} 5,\|XQA5!  
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public void splitterStop() def\=WyK  
{ x&$8;2&.  
bStop = true; Digx#'#jf  
} %/SHB  
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}
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/* N9u {)u  
**FileAccess.java o :j'd  
*//文件访问(定位，写) " BU4\QF-  
package NetFox; =dp`4
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import java.io.*; V|/N-3M  
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public class FileAccessI implements Serializable{ &4*f28 s  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /!60oV4p0  
RandomAccessFile oSavedFile; s=Kz9WLy  
long nPos; n-1  
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public FileAccessI() throws IOException Fw^^sB  
{
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this("",0); :*cd$s  
} V|<'o<h8  
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!
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public FileAccessI(String sName,long nPos) throws IOException 7'ws: #pC  
{ gRZ!=z[&  
oSavedFile = new RandomAccessFile(sName,"rw"); _<?z-K_;I  
this.nPos = nPos; l(}l([rdQ  
oSavedFile.seek(nPos); qVvnl  
} !yz3:Yzu  
=!/T4Oo  
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public synchronized int write(byte[] b,int nStart,int nLen) Wxi;Tq9C@_  
{ 5H( ]"C  
int n = -1; v7D0E[)~  
try{ $-\%%n0>6  
oSavedFile.write(b,nStart,nLen); v7@*dg  
n = nLen; $-(lp0\*  
} SUL\|z`5  
catch(IOException e) .73sY5hdTN  
{ @}'?o_/C  
e.printStackTrace (); Hdjp^O!  
} `*i:z'  
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return n; -1ci.4F&  
} ?}C8_I|4~  
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} }t1 q5@QU  
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/* j ~I_by  
**SiteInfoBean.java VI.Cmw~S  
*/ .{(gku>g(  
package NetFox; #=Whh 9-d  
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public class SiteInfoBean { FQ/z,it_i  
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dSS Ai |}  
private String sSiteURL; //Site's URL *QoQ$alHH  
private String sFilePath; //Saved File's Path R,-DP/ (im  
private String sFileName; //Saved File's Name cxIAI=JK  
private int nSplitter; //Count of Splited Downloading File "a<:fEsSE  
^Jc|d,u;s  
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public SiteInfoBean() XFi9qL^  
{//nSplitter的缺省值为5 04a@  
//default value of nSplitter is 5 r\q|DZ7  
this("","","",5); -8SZ}J  
} )t,efg  
A|m0.'/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) V}h)e3X  
{ 6-\M }xq?  
sSiteURL= sURL; ?~oc4J*>(  
sFilePath = sPath; ^>z+e"PQA  
sFileName = sName; Y{8}z ZD  
this.nSplitter = nSpiltter; Uu|R]azbO  
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} uao#=]?)  
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public String getSSiteURL() \{o<-S;h  
{ Qn@[{%),4  
return sSiteURL; d;).| .}P  
} qh6Q#s>tH  
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public void setSSiteURL(String value) pc;`Fz/`7  
{ Na+3aM%%  
sSiteURL = value; 1:q`KkJx  
} pwNF\ ={  
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!" @<!  
public String getSFilePath() /WIH#M  
{ Wyb+K)Tg  
return sFilePath; es\Fn#?O  
} <qBM+m$|)  
12}!oS~_  
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public void setSFilePath(String value) R^yh,  
{ +rka5ts  
sFilePath = value; (b7',:_U7  
} 8,)<,g-/=  
>|1-o;UU  
Yd<9Y\W%?  
public String getSFileName() h~ehZJys  
{ -.5R.~@  
return sFileName; Gf-GDy\{  
} }RUK?:lEA  
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public void setSFileName(String value) FMT_X  
{ ~e686L0j  
sFileName = value; E=ObfN"ge  
} D_BdvWSxj  
|)[&V3+|  
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public int getNSplitter() 6|1*gl1_LD  
{ S)`@)sr  
return nSplitter; ]<u%jTQREd  
} ~NIqO4 D  
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hcR^?  
public void setNSplitter(int nCount) ?v&2^d4C*F  
{ k|cP]p4,  
nSplitter = nCount; % "^CrG  
} ,hCbx#h  
} A$l  
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/* ,v#3A7"yW  
**Utility.java 4H`B]Zt7  
*/ :#=BwdC  
package NetFox; VYQ]?XF3i  
!4
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public class Utility { '_" S/X+v  
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H  
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public Utility() B
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{ B8>@q!G8P  
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} ,t39~w  
~l*[=0}  
//线程睡眠 1vCVTu
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public static void sleep(int nSecond) 5[P^O6'  
{ <4N E)!#  
try{ B.#-@  
Thread.sleep(nSecond); ix 5\Y  
} w} r mYQ  
catch(Exception e) tD]vx`0>  
{ }{.V^;  
e.printStackTrace (); r(g2&}o\  
} ^O**ZndB/  
} Ee=!bv(%70  
+xNq8yS  
//日志 E/_n}$Z  
public static void log(String sMsg) Hh%|}*f_,  
{ 35YDP|XZb  
System.err.println(sMsg); pK)!o  
} v5.KCc}"  
unyU|B  
ZsGJ[  
public static void log(int sMsg) N^jr  
{ }L>0}H  
System.err.println(sMsg); ~_ko$(;A  
} (>gb9n  
} +SkfT4*U  
#W/ATsDt  
$Eo-58<q  
/* K%;=i2:  
**TestMethod.java t5EYu*  
*/
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package NetFox; c`7dNx  
Y7 e1%,$v  
yRt7&,}zL  
public class TestMethod { aQ0pYk~(  
1c4:'0  
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public TestMethod() =an0PN  
{ ///xx/weblogic60b2_win.exe e,l-}=5*P  
try{ "
nU] 2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2FE
i-m}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); iO}KERfU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); LVJn2t^  
fileFetch.start(); K/8TwB
?I  
} TmJXkR.5  
catch(Exception e){e.printStackTrace ();} RT[E$H  
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/$|-!e<5b\  
} Sea6xGdq  
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public static void main(String[] args) 0m4'm<2m  
{ b T** y?2  
new TestMethod(); RJdijj  
} V2$M`|E  
} )oZ2,]us!  
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