http断点续传简单实现（java)

/*  J7p?9  
**SiteFileFetch.java >;+q,U}  
*/ w:/QB-`%  
package NetFox; T[%@B"  
import java.io.*; yeIcQ%  
import java.net.*; vQmqYyOc2  
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public class SiteFileFetch extends Thread { PH>`//D%n?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean gXe`G(w  
long[] nStartPos; //开始位置 C=&;4In  
long[] nEndPos; //结束位置 FY"csZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 u1ahAk7  
long nFileLength; //文件长度 ]}L tf,9  
boolean bFirst = true; //是否第一次取文件 }Apn.DYbbf  
boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 A$-\Er+f  
DataOutputStream output; //输出到文件的输出流 V;uFYt;E  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） t4<+]]   
public SiteFileFetch(SiteInfoBean bean) throws IOException 9{8xMM-  
{ nx
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siteInfoBean = bean; <ToRPx&E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U &
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gbziEjRe  
if(tmpFile.exists ()) @.} @K  
{ nJY3 1(p  
bFirst = false; !7Nz_d~n  
read_nPos(); c{[lT2yxU  
} v$#l]A_D  
else R7/ET"  
{ i!yE#z
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nStartPos = new long[bean.getNSplitter()]; 9*2^2GR^;  
nEndPos = new long[bean.getNSplitter()]; IGF25-7B  
} Q:8t1ZDo  
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, FR/X/8  
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} ei(S&u<  
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public void run() GezMqt;2  
{ %|'VucLx  
//获得文件长度 ]E^)d|_  
//分割文件 8/R9YiY5*  
//实例FileSplitterFetch Dq+S'x~>  
//启动FileSplitterFetch线程 v\D.j4%ij  
//等待子线程返回 Y|ErVf4  
try{ :ZadPn56  
if(bFirst) 8wMwS6s:  
{ F
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nFileLength = getFileSize(); CIj7'V  
if(nFileLength == -1) p#6tKY;N  
{ +!)_[ zo  
System.err.println("File Length is not known!"); GOD{?#
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} f<M!L>+M6  
else if(nFileLength == -2) i?f;C_w  
{ L| ;WE=  
System.err.println("File is not access!"); K9ek  
} *z&hXYm  
else [DvQk?,t  
{ yz=aJ v; H  
for(int i=0;i<nStartPos.length;i++) \LM.>vJ  
{ }^2'@y!(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N
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} ~l]g4iEp  
for(int i=0;i<nEndPos.length-1;i++) (XEJd4r  
{ -6$GM J7  
nEndPos = nStartPos[i+1]; 3sp-0tUE  
} `%*`rtZ+H.  
nEndPos[nEndPos.length-1] = nFileLength; n?"("Fiw  
} 'xGTaKlm,  
} tac\Ki?  
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gv1y%(`|n(  
//启动子线程 .-)kIFMi  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zb
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for(int i=0;i<nStartPos.length;i++) ?C']R(fQ\  
{ g}pD%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }s[`T   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), e m  
nStartPos,nEndPos,i); $g),|[x+(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WEtPIHruyt  
fileSplitterFetch.start();  HlEHk'  
} J?Oeuk~[D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -q\Rbb5M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); U$;UW3-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]n3!%0]\  
nEndPos = " + nFileLength); J$lfI^^  
// fileSplitterFetch[nPos.length-1].start(); 45&Rl,2  
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//等待子线程结束 =}YX I  
//int count = 0; 6"; ITU^v  
//是否结束while循环 | ^G38  
boolean breakWhile = false; )S;3WnQ)  
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while(!bStop) u60RuP&  
{ M6GiohI_"P  
write_nPos(); zrf tF2U  
Utility.sleep(500); wD4[UU?  
breakWhile = true; zRb
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for(int i=0;i<nStartPos.length;i++) ;#9ioGx  
{ =3!o_  
if(!fileSplitterFetch.bDownOver) Ubgn^+AI  
{ O<E8,MCA[a  
breakWhile = false; \0vs93>?  
break; tG ZMIG_  
} Cy)N hgz  
} e\O-5hp7  
if(breakWhile) AyPtbrO  
break; $/|vbe,  
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//count++; ^bP`Iv  
//if(count>4) 57=d;Yg e  
// siteStop(); -y{(h%6  
} g[bu9i  
*,IK4F6>:  
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System.err.println("文件下载结束！"); P$Oj3HD LM  
} paLPC&G  
catch(Exception e){e.printStackTrace ();} *C<;yPVc  
} 
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//获得文件长度 =,h'}(z_  
public long getFileSize() Dh}(B$~Oz+  
{ 6B|i-b$~  
int nFileLength = -1; vZ811U~}  
try{ L#uU.U=  
URL url = new URL(siteInfoBean.getSSiteURL()); x
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &1R#!|h1W  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9x|`XAB  
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int responseCode=httpConnection.getResponseCode(); P/.<sr=2  
if(responseCode>=400) miu?X!  
{ ^X}r ^  
processErrorCode(responseCode); vSC1n8 /  
return -2; //-2 represent access is error DBL@Mp[<  
} *YL86R+U  
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String sHeader; 2[HPU M2>  
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for(int i=1;;i++) RL/y7M1j  
{ BV:Ca34&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); IZ7o6Etti  
//Utility.log(in.readLine()); Nw$OJ9$L>  
sHeader=httpConnection.getHeaderFieldKey(i); [DH4
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if(sHeader!=null) )E*f30  
{ NsP=l]   
if(sHeader.equals("Content-Length")) !%ju.Xs8  
{ t!*[nfR  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); GWWg3z.o"W  
break; peBHZJ``RX  
} c:u*-lYmK%  
} <%Nf"p{K  
else 0NGth(2  
break; GIH{tr1:<  
} W"\}##  
} 7@%qm|i>w  
catch(IOException e){e.printStackTrace ();} =eUKpYI  
catch(Exception e){e.printStackTrace ();} 6XF Ufi+  
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Utility.log(nFileLength); vj%"x/TP  
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return nFileLength; 5L[imOM0  
} 41<h|WA  
n=V|NrU  
*3fl}l  
//保存下载信息（文件指针位置）
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private void write_nPos() $<nRW*d  
{ oo\^}jb  
try{ L%/>Le}VX  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Os'E7;:1h  
output.writeInt(nStartPos.length); py:L-5  
for(int i=0;i<nStartPos.length;i++) 1C{0
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{ oSD=3DQ;  
// output.writeLong(nPos); `e<IO_cg  
output.writeLong(fileSplitterFetch.nStartPos); Gg9s.]W  
output.writeLong(fileSplitterFetch.nEndPos); qsW&kW~  
} ?V8Fgd  
output.close(); wg%Z  
} mc%. 8i  
catch(IOException e){e.printStackTrace ();} Z9$pY=8^?  
catch(Exception e){e.printStackTrace ();} `WOoC  
} 7;q0'_G  
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//读取保存的下载信息（文件指针位置） Zt!$"N.,  
private void read_nPos() <Hr<QiAK  
{ [-VH%OM  
try{ H!]&
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8|)!E`TKSV  
int nCount = input.readInt(); r4/b~n+*  
nStartPos = new long[nCount]; A?#i{R  
nEndPos = new long[nCount]; jFdgFKc)  
for(int i=0;i<nStartPos.length;i++) H"? 5]!p  
{ ,+`r2}N \/  
nStartPos = input.readLong(); _]o7iqtv  
nEndPos = input.readLong(); onSt%5{P%X  
} [k\VUg:P  
input.close(); ,Ohhl`q(  
} K
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catch(IOException e){e.printStackTrace ();} @
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catch(Exception e){e.printStackTrace ();} ;%2+Tc-7I  
} $7Hwu^c(  
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private void processErrorCode(int nErrorCode) ffL]_E  
{ eC"e v5v  
System.err.println("Error Code : " + nErrorCode); ~3j+hN8<  
} )uHat#  
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faRQj:R8  
//停止文件下载 cQ-#]  
public void siteStop() 6/L[`n"G  
{ cI8\d 4/py  
bStop = true; c!6v-2ykv  
for(int i=0;i<nStartPos.length;i++) -{OJM|W+  
fileSplitterFetch.splitterStop(); (Ud"+a  
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} >g!$H}\  
} Dz~^AuD6  
//负责部分文件的抓取 paV1o>_Rd  
**FileSplitterFetch.java >ph=?MKD  
*/ .jP|b~  
package NetFox; U9`Co&Z2  
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import java.io.*; 2 oL$I(83  
import java.net.*; I_8 n>\u  
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public class FileSplitterFetch extends Thread { J)Yz@0#T(;  
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String sURL; //File URL q/*veL  
long nStartPos; //File Snippet Start Position ]lGkZyUhI  
long nEndPos; //File Snippet End Position ]]r;}$  
int nThreadID; //Thread's ID `dX0F=Ag?  
boolean bDownOver = false; //Downing is over ux^rF  
boolean bStop = false; //Stop identical Ew.6y=Ba  
FileAccessI fileAccessI = null; //File Access interface w8q 2f-K-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException GBS+ 4xL|  
{ vD#kH1  
this.sURL = sURL; imM#zy  
this.nStartPos = nStart; NoF|j57?u'  
this.nEndPos = nEnd; k fY;  
nThreadID = id; vAG|Y'aO@%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 % mPv1$FH  
} 6:QlHuy0nH  
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public void run() ODRy  
{ _Hx'<%hhI  
while(nStartPos < nEndPos && !bStop) w?"M  
{ ]!"7k_  
}vP
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try{ mIrN~)C4\  
URL url = new URL(sURL); W"\`UzOLQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]T5\LNyN  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2V; Dn$q  
String sProperty = "bytes="+nStartPos+"-"; 2Gj)fMK38  
httpConnection.setRequestProperty("RANGE",sProperty); W4P\HM>2  
Utility.log(sProperty); *e:I*L  
\AI-x$5R*  
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InputStream input = httpConnection.getInputStream(); fO#nSB/ 8  
//logResponseHead(httpConnection); 9RSviIi$  
/Trbr]lWy  
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byte[] b = new byte[1024]; * _usVg  
int nRead; /={N^8^=x  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) SuI^8^f=  
{ %)d7iT~M  
nStartPos += fileAccessI.write(b,0,nRead); }[c.OJ:   
//if(nThreadID == 1) i;qij[W.z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g^po$%I '  
} &>Z;>6J,  
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Utility.log("Thread " + nThreadID + " is over!"); jc!V|w^  
bDownOver = true; iW9  
//nPos = fileAccessI.write (b,0,nRead); nu|,
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} M djxTr^  
catch(Exception e){e.printStackTrace ();} =l] lwA-  
} )L":I  
} [T[]U  
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W"t^t|H'~  
//打印回应的头信息 \j.l1O  
public void logResponseHead(HttpURLConnection con) >s.y1Vg~C  
{ d mTZEO  
for(int i=1;;i++) F]<2nb7  
{ ,5T1QWn^f  
String header=con.getHeaderFieldKey(i); Tgla_sMb  
if(header!=null) *].qm g%  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  Bw+?MdS  
Utility.log(header+" : "+con.getHeaderField(header)); R S>qP;V*-  
else 4}*.0'Hz  
break; 3-Xd9ou  
} S|6i]/  
} q^ &r<i  
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public void splitterStop() S {+Z.P  
{ KCp9P2kv.  
bStop = true; BbL]0i  
} /m^G 99N  
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} ~oK0k_{~  
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/* JnqP`kYbTE  
**FileAccess.java 0$=U\[og  
*//文件访问(定位，写) 'w<^4/L Q  
package NetFox; \;Q!}_ K  
import java.io.*; <7L-25 =  
4? rEO(SZ  
:v$)Z~  
public class FileAccessI implements Serializable{ z/p^C~|}  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 i],~tT|P  
RandomAccessFile oSavedFile; |942#rM  
long nPos; v:9'k~4)  
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public FileAccessI() throws IOException eE;j#2SEO  
{ &%(SkL_]  
this("",0); _~P&8  
} L`9.Gf  
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public FileAccessI(String sName,long nPos) throws IOException 1>2 /1>  
{ >f1fvv
6  
oSavedFile = new RandomAccessFile(sName,"rw"); m0^~VK|  
this.nPos = nPos; "WbKhE  
oSavedFile.seek(nPos); qa8?bNd'f  
} wM-H5\9n  
p=i6~   
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public synchronized int write(byte[] b,int nStart,int nLen) J^PFhu  
{ hew"p(`  
int n = -1; D+q z`  
try{ ,u-9e4  
oSavedFile.write(b,nStart,nLen); 1C*mR%Q  
n = nLen; "W9z>ezp  
} 2$o\`^dy  
catch(IOException e) !#e+!h@  
{ :gRVa=}=  
e.printStackTrace (); 43rV> W,  
} *#?9@0b@  
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return n; ;.R) uCd{=  
} I58$N+#  
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*
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} E7B?G3|z3  
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/* fZnq5r
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**SiteInfoBean.java EEx:Xk%5hX  
*/ M}=>~TA@  
package NetFox; cveQ6 -`K  
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public class SiteInfoBean { VT#`l0I}  
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private String sSiteURL; //Site's URL $}us+hGZ  
private String sFilePath; //Saved File's Path hVd_1|/X  
private String sFileName; //Saved File's Name u6MU @?  
private int nSplitter; //Count of Splited Downloading File )?6%d  
f9d{{u  
rD !GEU
 
public SiteInfoBean() w2lO[o~x}  
{//nSplitter的缺省值为5 z('t#J!b  
//default value of nSplitter is 5 `/B+  
this("","","",5); qc'
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} 4#ikdjB;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'tX}6wurf  
{ M+lr [,c  
sSiteURL= sURL; QDKY7"H  
sFilePath = sPath; y!q`o$nK  
sFileName = sName; 4|4[3Ye7u:  
this.nSplitter = nSpiltter; 0eK>QZ_  
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} {V8uk
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public String getSSiteURL() W?[ C au-  
{ /2tPd  
return sSiteURL; >?ec"P%vS/  
} \pP1k.~UnC  
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public void setSSiteURL(String value) *,=8x\Shp  
{ x]4>f[>*>  
sSiteURL = value; /R>YDout}  
} [Ov/&jD"  
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public String getSFilePath() )XoMOz  
{ n{M-t@r7  
return sFilePath; O2U}jHsd  
} `v'yGsIV  
!:}m-iqQ1  
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public void setSFilePath(String value) _'n]rQ'  
{ Rh)
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sFilePath = value; dh%
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} 6:?mz;oP  
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public String getSFileName() SEE:v+3|  
{ +k/=L9#e  
return sFileName; GXRW"4eF5  
} _3#_6>=M  
:Smyk.B2!  
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public void setSFileName(String value) :lK8i{o  
{ vZ^U]h V  
sFileName = value; abS3hf  
} 0w vAtK|Q  
8I<j"6`+Q  
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public int getNSplitter() I$XwM  
{ Y@ vC!C  
return nSplitter; F
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} 7I;0%sVQ{  
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public void setNSplitter(int nCount) $if(n||  
{ kUr/*an  
nSplitter = nCount; kxmsrQ
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} 8Au W>7_  
} }%^3  
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/* *?>52 -&b  
**Utility.java Pu'NSNT  
*/ zz8NBO  
package NetFox; (UTA3Db  
/J(~NGT  
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public class Utility { - rI4_Dl  
42:,*4t(  
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public Utility() def\=WyK  
{ m\_v{1g  
%/SHB  
=Ew77  
} `7.$ A U  
[fs.D /  
//线程睡眠 hZ')<@hNP  
public static void sleep(int nSecond) x1"8K  
{ M<SVH_  
try{ 1bjWWNzQA  
Thread.sleep(nSecond); ):n'B` f}z  
} gf^y3F[\  
catch(Exception e) PtGFLM9R  
{ 4E$d"D5]>p  
e.printStackTrace (); }*vE/W  
} AXv-%k};  
} BHU=TK@GR  
|EY1$qItid  
//日志 Ql,WKoj*  
public static void log(String sMsg) q#"lnc<S  
{ [}}q/7Lp  
System.err.println(sMsg); w BoP&l  
} &gI*[5v  
2;w> w#}>  
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public static void log(int sMsg) s=Kz9WLy  
{ n-1  
System.err.println(sMsg); 29&F_  
} a|k*A&5u2  
} 4y$okn\}i  
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/* M7YbRl  
**TestMethod.java ?ea5k*#a  
*/ n>)h9q S  
package NetFox; Gq7\b({=  
m]}EVa_I`/  
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public class TestMethod { +KOhDtLMG  
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public TestMethod() %2^V.`0T  
{ ///xx/weblogic60b2_win.exe Ym$`EN  
try{ :zpT Gk8Z  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `6PBV+]Vm3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^__P;Gr`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]jR-<l8I-  
fileFetch.start(); ]
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} JtF)jRB0,  
catch(Exception e){e.printStackTrace ();} g O8~$Aj  
|:`)sx3@#  
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} BLm}mb#/{  
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public static void main(String[] args) &0{&4,  
{ _6]tbni?v  
new TestMethod(); U?Vik  
} 8rNf4]5@X(  
} "i!W(}x+  
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