http断点续传简单实现（java)

/* OgpH{"  
**SiteFileFetch.java fbbl92p  
*/ lDM~Z3(/b  
package NetFox; "a_D]D(d5  
import java.io.*;  B*~Bm.  
import java.net.*; QcVtv7+*v  
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public class SiteFileFetch extends Thread { V5^b6$R@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean R~?;KJ  
long[] nStartPos; //开始位置 CjukD%>sde  
long[] nEndPos; //结束位置 oL/^[TXjH  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .mU.eL
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long nFileLength; //文件长度 NGeeD?2~  
boolean bFirst = true; //是否第一次取文件 rH_:7#.E  
boolean bStop = false; //停止标志 uEO2,1+  
File tmpFile; //文件下载的临时信息 8t 35j  
DataOutputStream output; //输出到文件的输出流 GP kCgb(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Oh85*3  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?F), 4Q  
{ uF|ix.R6  
siteInfoBean = bean; >WS&w;G  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wk7_(gT`0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); FH5bC6  
if(tmpFile.exists ()) 2A;[Ek6{q  
{ sNpBTG@{l  
bFirst = false; m6ws#%|[  
read_nPos(); cNB$g )`  
} uTt:/gm  
else FwzA_ nn  
{ _+Kt=;Y8  
nStartPos = new long[bean.getNSplitter()]; 2g8P$+;  
nEndPos = new long[bean.getNSplitter()]; $%"}N_M  
} N5_.m(:  
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} PvBbtC-9b  
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public void run() !>);}J!e]  
{ 5K-)X9z?  
//获得文件长度 *M<=K.*\G  
//分割文件 ]<?)(xz  
//实例FileSplitterFetch 1KR|i"  
//启动FileSplitterFetch线程 &>b1ES.>  
//等待子线程返回 ?
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try{
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if(bFirst) {!?RG\EYN  
{ n\p\*wb  
nFileLength = getFileSize(); D}U<7=\3H  
if(nFileLength == -1) Bj
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{ oVsazYJ|?  
System.err.println("File Length is not known!"); YfU#kvE'  
} k0uwG'(z9  
else if(nFileLength == -2) oKJ7i,xT  
{ <|G~S<y}  
System.err.println("File is not access!"); ~ b_gwJ'  
} #iDFGkK/  
else ! HC<aWb  
{ *c c+
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for(int i=0;i<nStartPos.length;i++) YY
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{ Czxrn2p/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cY]Y8T)  
} <~*Ol+/  
for(int i=0;i<nEndPos.length-1;i++) Y--8v#t  
{ kw}1CXD  
nEndPos = nStartPos[i+1]; 4^^rOi0  
} u\?u4  
nEndPos[nEndPos.length-1] = nFileLength; eV%bJkt.  
} sB/s17ar  
} p>
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//启动子线程 K7VG\
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Vgk,+l!4  
for(int i=0;i<nStartPos.length;i++) wKbymmG  
{ %"^XxVJ*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e.^9&Fk"N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *v3 |  
nStartPos,nEndPos,i); ^eRT8I  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AwrK82  
fileSplitterFetch.start(); wO%:WL$5  
} _If?&KJ r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); BF
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +N@F,3yNa  
nEndPos = " + nFileLength); I!O S&8:u  
// fileSplitterFetch[nPos.length-1].start(); ~=ys~em e  
!17Z\Ltqyj  
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//等待子线程结束 d vxEXy  
//int count = 0; wCmv/m  
//是否结束while循环 jtY~-@*  
boolean breakWhile = false; VAt9JE;#  
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while(!bStop) 1z:N$O_v  
{ )c !S@Hs  
write_nPos(); GA}^Rh`T-  
Utility.sleep(500); Uroj%xN  
breakWhile = true; aB'@8[]z  
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for(int i=0;i<nStartPos.length;i++) sdD[`#  
{ = h( n+y<  
if(!fileSplitterFetch.bDownOver) Ti'kn{ Zv  
{ ?Fpl.t~  
breakWhile = false; e8bJ]  
break; 3>Snd9Q  
} %/zZ~WIf  
} xv
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if(breakWhile) i@L2W>{P  
break; [+z:^a1?V  
 0 XzO`*  
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//count++; Y cpO;md  
//if(count>4) 7bS[\5  
// siteStop(); %m3efaC  
} 0g-ESf``{n  
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System.err.println("文件下载结束！"); "mK (?U!A  
} SI5QdX  
catch(Exception e){e.printStackTrace ();} Bx4GFCdifC  
} ]E^f8s0#V  
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//获得文件长度 6QQ oHYtZ  
public long getFileSize() <vDm(-i3  
{ ?%Fk0E#>2  
int nFileLength = -1; UULL:vqq  
try{ \ 6a  
URL url = new URL(siteInfoBean.getSSiteURL()); z?[DW*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k)Wz b  
httpConnection.setRequestProperty("User-Agent","NetFox"); {m:Rv&T  
/ u6$M/Cf>  
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int responseCode=httpConnection.getResponseCode(); F-0PmO~3+W  
if(responseCode>=400) or`stBx  
{ |'
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processErrorCode(responseCode); [rU8 #4.  
return -2; //-2 represent access is error 89mre;v`  
} )n@3@NV  
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String sHeader; /GGu` f  
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for(int i=1;;i++) V}+;bbUc-  
{ Y'1V(5/&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); yG$@!*|  
//Utility.log(in.readLine()); :PkZ(WZ9  
sHeader=httpConnection.getHeaderFieldKey(i); 8f5^@K\c  
if(sHeader!=null) wkA!Jv%  
{  _Qc\v0%  
if(sHeader.equals("Content-Length")) 3HR]TQ%r  
{ S]O Hv6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); uf]$@6)  
break; >+8I =S  
} w[YbL2p  
} NI:N W-!  
else 5N<v'6&=  
break; 1G.gPx[  
} olxP`iK  
} 6qpV53H  
catch(IOException e){e.printStackTrace ();} \zL7j4  
catch(Exception e){e.printStackTrace ();} T?{9Z  
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Utility.log(nFileLength); -wMW@:M_  
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return nFileLength; }/3pC a  
} [;YBX]t  
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UVUO}B@[S  
//保存下载信息（文件指针位置） i9U_r._qj;  
private void write_nPos() _rdj,F8  
{ 1t=X: ]0j  
try{ $!
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output = new DataOutputStream(new FileOutputStream(tmpFile)); yUwgRj  
output.writeInt(nStartPos.length); q'@Ei4  
for(int i=0;i<nStartPos.length;i++) i9k]Q(o  
{ u;qMo`-  
// output.writeLong(nPos); m>dcb 6B+g  
output.writeLong(fileSplitterFetch.nStartPos); C-^%g[#  
output.writeLong(fileSplitterFetch.nEndPos); H<7DcwXv  
} kS#DKo  
output.close(); bRz^=  
} ,Ysl$^\  
catch(IOException e){e.printStackTrace ();} mX.3R+t  
catch(Exception e){e.printStackTrace ();}
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} Mq lo:7 ^F  
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//读取保存的下载信息（文件指针位置） 33*d/%N9  
private void read_nPos() aX'g9E
 
{ ww t()  
try{ ^H6d;n  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); pQ^,.[[  
int nCount = input.readInt(); TKu68/\)  
nStartPos = new long[nCount]; 7h#faOP  
nEndPos = new long[nCount]; 4S0++Hp
4  
for(int i=0;i<nStartPos.length;i++) JBEgiQ/  
{ W%9K5(e  
nStartPos = input.readLong(); Y\Qxdq  
nEndPos = input.readLong(); ])j|<W/  
} K#f`_SCW  
input.close(); u$=ogp=0  
} w*xUuwi  
catch(IOException e){e.printStackTrace ();} }-q`&1!t
 
catch(Exception e){e.printStackTrace ();} '}pgUh_  
} ' raB  
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private void processErrorCode(int nErrorCode) (GcKaUg8*  
{ ml33qXW:  
System.err.println("Error Code : " + nErrorCode); ^&';\O@)  
} ;.Oh88|k  
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//停止文件下载 H"q`k5R  
public void siteStop() n &\'Hm  
{ J6( RlHS;  
bStop = true; +>WC^s  
for(int i=0;i<nStartPos.length;i++) qz=#;&ZU  
fileSplitterFetch.splitterStop(); <r+!hJ[s'  
,*nZf|  
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} xV>iL(?  
} [bi3%yWh  
//负责部分文件的抓取 vMZ7uO  
**FileSplitterFetch.java L_lDFF  
*/ 4$zFR}f  
package NetFox; ZkB6bji  
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import java.io.*; *)`kx  
import java.net.*; :m++ iR  
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public class FileSplitterFetch extends Thread { FSU%?PxO  
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String sURL; //File URL =2nn "YVP  
long nStartPos; //File Snippet Start Position n,?IcDU~m  
long nEndPos; //File Snippet End Position OSa
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int nThreadID; //Thread's ID 4Ay`rG  
boolean bDownOver = false; //Downing is over j.;  
boolean bStop = false; //Stop identical fZ6 fV=HEF  
FileAccessI fileAccessI = null; //File Access interface % L >#  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5@UC c  
{ uh5Pn#da^  
this.sURL = sURL;
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this.nStartPos = nStart; <K,% y(]  
this.nEndPos = nEnd; O@r.>  
nThreadID = id; ckf<N9  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 RrO0uadmn  
} Q$3\ /mz  
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public void run() s^g.42?u  
{ .L^pMU+!^  
while(nStartPos < nEndPos && !bStop) bCA2ik  
{ <g3du~  
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try{ )+n,5W  
URL url = new URL(sURL); p<=(GY-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v@fe-T&0  
httpConnection.setRequestProperty("User-Agent","NetFox"); O}K
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String sProperty = "bytes="+nStartPos+"-"; -t@y\vZF,  
httpConnection.setRequestProperty("RANGE",sProperty); b W=.K>|  
Utility.log(sProperty); 3!.H^v?  
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InputStream input = httpConnection.getInputStream(); >bfYy=/  
//logResponseHead(httpConnection); }XX~ W}M(\  
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byte[] b = new byte[1024]; "U%n0r2  
int nRead; Ml8 YyF/~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Uvjdx(fY[a  
{ GOy=p3mQ  
nStartPos += fileAccessI.write(b,0,nRead); t."g\;  
//if(nThreadID == 1) #`jE%ONC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jl.okWuiY  
} ""1#bs{n  
bBUbw*DF)  
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Utility.log("Thread " + nThreadID + " is over!"); w]>"'o{{  
bDownOver = true; &W=V%t>Z  
//nPos = fileAccessI.write (b,0,nRead); OUEI~b1  
} kmm  
catch(Exception e){e.printStackTrace ();} nu&_gF,{  
} ~ X-)_zH  
} =X-^YG3x  
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//打印回应的头信息 m#oh?@0}  
public void logResponseHead(HttpURLConnection con) ([:]T$0 #  
{ r<;l{7lY_  
for(int i=1;;i++) t)-*.qZh  
{ }J
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String header=con.getHeaderFieldKey(i); C%giv9a  
if(header!=null) ^"3\iA:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 06 QU  
Utility.log(header+" : "+con.getHeaderField(header)); )!tCC-Cr  
else e8$l0gzaD  
break; yGU .AM  
} 7#QLtU  
} uxWFM $  
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public void splitterStop() =EQJqj1T  
{ 0y)}.'  
bStop = true; x&'o
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} c\At0.QCA  
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} >DHp*$y  
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/* W+_RhJ  
**FileAccess.java OFA{ KZga  
*//文件访问(定位，写) rah,dVE]  
package NetFox; d')-7C  
import java.io.*; #O"  
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public class FileAccessI implements Serializable{ *I0Tbc O  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 U[R@x`  
RandomAccessFile oSavedFile; 9M_(He -  
long nPos; f;gZ|a  
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public FileAccessI() throws IOException Cp#)wxi6[y  
{ 5!Bktgk.  
this("",0); '_dzcN,z  
} w1r$='*I  
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public FileAccessI(String sName,long nPos) throws IOException 1j0-9Kg'  
{ z>;$im  
oSavedFile = new RandomAccessFile(sName,"rw"); @b2`R3}9R  
this.nPos = nPos; c8{]]  
oSavedFile.seek(nPos); YD\]{,F|  
} Q/ZkW  
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public synchronized int write(byte[] b,int nStart,int nLen) |9Yi
7.  
{ `Gd$:qV  
int n = -1; !g>.i`  
try{ ]u#JuX  
oSavedFile.write(b,nStart,nLen); &.Q8Mi aT  
n = nLen; ymWgf6r<  
} ;;Ds  
catch(IOException e) {fV}gR2  
{ :m'+tGs  
e.printStackTrace (); vMla'5|l  
} NOt@M  
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return n; K=?VDN  
}
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} |.P/:e9  
Fl3#D7K  
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/* K>2#UzW  
**SiteInfoBean.java AW,OHSXh6  
*/ 'Z&;uv,l  
package NetFox; 4v'A\~ZU  
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public class SiteInfoBean { d2S~)/@S  
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private String sSiteURL; //Site's URL X"q!Y#)  
private String sFilePath; //Saved File's Path k~3.MU  
private String sFileName; //Saved File's Name in-C/m#  
private int nSplitter; //Count of Splited Downloading File Q;u SWt<{  
U__(; /1;  
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public SiteInfoBean() Thr*^0$C  
{//nSplitter的缺省值为5 {g6Qv-  
//default value of nSplitter is 5 ;AJTytE>%  
this("","","",5); Ucdj4[/,h  
} T]T;$  
}_ mT l@*  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ($nrqAv4  
{ ~8T(>!hE1h  
sSiteURL= sURL; ,8MLoZ_  
sFilePath = sPath; BZv+H=b  
sFileName = sName; v"^~&q0x  
this.nSplitter = nSpiltter; w}R~C  
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} *&Lq!rFS  
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public String getSSiteURL() ,TJD$^  
{ 6t'l(E +  
return sSiteURL; C1EtoOv K  
} 8qEK+yi,  
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public void setSSiteURL(String value) 'CZa3ux  
{ Va V
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sSiteURL = value; t*<#<a  
} h].~#*  
<"D=6jqZ  
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public String getSFilePath() C[!MS5  
{ ?E%ELs_Dl  
return sFilePath; !HeSOzN  
} {gNV[45  
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public void setSFilePath(String value) 73#x|lY  
{ !+)AeDc:j  
sFilePath = value; obrl#(\P  
} -x8nQ%X  
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public String getSFileName() ##Q/I|  
{ ^EG\iO2X  
return sFileName; gBh;=vOD  
} CC\*?BKj"  
:1XtvH  
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public void setSFileName(String value) #_Z$2L"U  
{ 'TH15r@  
sFileName = value; \I"Z2N>^z  
} wn_b[tdxq  
/!^&;$A'  
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public int getNSplitter() ae:zWk'!  
{ 7\*FEjRM]  
return nSplitter; '>$]{
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} 2C{H$ A,pW  
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public void setNSplitter(int nCount) 5JEbe   
{ qd"_Wu6aF=  
nSplitter = nCount; p.+ho~sC,.  
} mUS_(0q  
} 2z\zh[(w  
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/* 8 k3S  
**Utility.java >pU:Gr  
*/ ;<G=M2  
package NetFox; ~QvqG{bFB  
"\0v,!@  
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public class Utility { PJcwH6m  
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public Utility() }%Bl>M
  
{ [<'-yQ{l\  
f!
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} @as"JAN  
@+atBmt  
//线程睡眠 7^w >Rj  
public static void sleep(int nSecond) NPFpq,P>  
{ vN3Zr34  
try{ BD`2l!d  
Thread.sleep(nSecond); ?nP*\8  
} ]p_@@QTC  
catch(Exception e) 5jUYN-$GO  
{ C@jJ.^ <<  
e.printStackTrace (); $.9{if#o&  
} XJLQ{  
} gY@N~'f;"  
J>u
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//日志 i hh/sPi  
public static void log(String sMsg) .BFYY13H  
{ SPp#f~%m  
System.err.println(sMsg); ID#I`}h.k  
} ?B:a|0pf  
#>j.$2G>  
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public static void log(int sMsg) |=&cQRY!p  
{ cI=(\pC  
System.err.println(sMsg); sJ]taY ou  
} [,TkFbDq"J  
} qL,tYJ<m%  
3>Y6)  
_6wFba@>/n  
/* G#MdfKH  
**TestMethod.java 1 5A*7|  
*/ n5{Xj:}  
package NetFox; nxr!`^Mne  
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public class TestMethod { (&!NC[n,  
&LbJT$}V  

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public TestMethod() YX`7Hm,  
{ ///xx/weblogic60b2_win.exe Fy.\7CL>  
try{ v'e[GB0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); clk[/'1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7e<c$t#H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _r2J7&  
fileFetch.start(); Aj0Tfdxy  
} VZ\B<i  
catch(Exception e){e.printStackTrace ();} *W kIq>  
f"St&q>[s  
O)"gS!,  
} 9D4NX<_  
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public static void main(String[] args) 0pbtH8~  
{ ;6!Pwb;hY  
new TestMethod(); c_V;DcZ  
} <A# l 35  
} KG=
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