http断点续传简单实现（java)

/* +.uQToqy  
**SiteFileFetch.java vLGnLpt  
*/ 0="wxB  
package NetFox; {??bJRT  
import java.io.*; ^3QJv{)Q  
import java.net.*; {9cjitl  
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public class SiteFileFetch extends Thread { lnK#q.]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean $M$-c{>s  
long[] nStartPos; //开始位置 I2,AT+O<  
long[] nEndPos; //结束位置 [* |+ it+!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }-T,cA
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long nFileLength; //文件长度 q RRvZhf  
boolean bFirst = true; //是否第一次取文件 r$Oa  
boolean bStop = false; //停止标志 c IPOI'3d  
File tmpFile; //文件下载的临时信息 a.
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DataOutputStream output; //输出到文件的输出流 ;R$2+9  
!%N@>[  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {TDZDH  
public SiteFileFetch(SiteInfoBean bean) throws IOException g|tcl
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{ *n6L3"cO  
siteInfoBean = bean; ~_wSB[z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); F!-
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Q07&7SH_  
if(tmpFile.exists ()) FB %-$  
{ FbXur-et^  
bFirst = false; N@^:IfJ+=  
read_nPos(); ,E"n7*6mr  
} DHZ`y[&}|N  
else SF da?>  
{ v4XEp   
nStartPos = new long[bean.getNSplitter()]; Xv+,Z<>iQ  
nEndPos = new long[bean.getNSplitter()]; D2RvFlAXu  
} \m=k~Cf:f  
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} N*)O_Ki  
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public void run() +zEyCx=8H  
{ hS&.-5v  
//获得文件长度 2Ux
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//分割文件 yR"mRy1  
//实例FileSplitterFetch lNTbd"}$:  
//启动FileSplitterFetch线程 Fh/sD?  
//等待子线程返回 [2!C^\t  
try{ xqQK-?k  
if(bFirst)
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{ Mh{>#Gs  
nFileLength = getFileSize(); Eqh*"hE7  
if(nFileLength == -1) T wzpq1  
{ ;s-@m<  
System.err.println("File Length is not known!"); tq51;L  
} LjIkZ'HuF  
else if(nFileLength == -2) nYe:$t3F=  
{ 9Q'[>P=1  
System.err.println("File is not access!"); p1W6s0L  
} R`B} T<*
  
else #w:nj1{_  
{ gEw9<Y  
for(int i=0;i<nStartPos.length;i++) 0E)M6 jJ  
{ "8~PfLJ+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,H1K
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} }F|B'[wn  
for(int i=0;i<nEndPos.length-1;i++) /U`p|M;  
{ }daU/  
nEndPos = nStartPos[i+1]; Wfy+9"-;s  
} ^x_$%8  
nEndPos[nEndPos.length-1] = nFileLength; KLG2
9G  
} YOUB%N9+  
} |*Oi:)qt  
p7HLSB2Rp  
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//启动子线程 DO(3hIj  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :6/$/`I0W  
for(int i=0;i<nStartPos.length;i++) !Uv>>MCr  
{ l]gW_wUQd  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q([{WZ:6Oq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ZB}A^X  
nStartPos,nEndPos,i); oxdX2"WwU  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B{p74 >  
fileSplitterFetch.start(); zg$ag4%Qgg  
} >8b%*f8R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ) TRUx  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); O%haaL\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &gUa^5'#  
nEndPos = " + nFileLength); {'z$5<|  
// fileSplitterFetch[nPos.length-1].start(); A(n#k&W1fZ  
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N Hn#c3o  
//等待子线程结束 _dmG#_1  
//int count = 0; 96P&+  
//是否结束while循环 2+Oz$9`.  
boolean breakWhile = false; 9hh~u -8L  
n{&;@mgI  
w'E?L`c  
while(!bStop) 2e03m62*  
{ ,eWLig  
write_nPos();  1'F!C  
Utility.sleep(500); EVC]B}  
breakWhile = true; M
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! h92dH  
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for(int i=0;i<nStartPos.length;i++) /Z,hQ>/  
{ ~qIr'?D  
if(!fileSplitterFetch.bDownOver) f^
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{ pM}~/  
breakWhile = false; xA`j:zn'j  
break; OiS\tK?|GV  
} 0s\ -iub=d  
} X8-x$07)  
if(breakWhile) <XtE|LG  
break; /+8VW;4|I  
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//count++; fre5{=@  
//if(count>4) pLys%1hg  
// siteStop(); )xKW  
} +r9neS.l  
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System.err.println("文件下载结束！"); E!BzE_|i  
} .U44p*I  
catch(Exception e){e.printStackTrace ();} S#r|?GYua  
} es~1@Jb  
#TC}paIpj  
y)a)VvU":  
//获得文件长度 =8%*Rrj^  
public long getFileSize() 1N:~5S}s>  
{ >EZZEd  
int nFileLength = -1; -ZyY95E<  
try{ xplV
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URL url = new URL(siteInfoBean.getSSiteURL()); Wq"-T.i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /oLY\>pD  
httpConnection.setRequestProperty("User-Agent","NetFox"); MLg{Y?@  
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int responseCode=httpConnection.getResponseCode(); K=nDC.  
if(responseCode>=400) k7;i^$@c  
{ /wl]kGF  
processErrorCode(responseCode); PxGw5:  
return -2; //-2 represent access is error >(wQx05^D  
} I|qhj*_C  
r| )45@  
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String sHeader; ~P"Agpx3u  
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!  
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for(int i=1;;i++) E`<ou_0N@q  
{ {K6Z.-.`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); R/*"N'nH-%  
//Utility.log(in.readLine()); &43c/TSb  
sHeader=httpConnection.getHeaderFieldKey(i); ~G-W|>  
if(sHeader!=null) 9 wbQ$>G9  
{ BV }CmU&DA  
if(sHeader.equals("Content-Length")) YOj&1ymBZ  
{ ~!Nw]lb!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); RqP_^tB  
break; RyG6_G}  
} B]:|;d  
} BzkfB:wr  
else F|qMo|  
break; 5E1`qof  
} `9+R]C]z8  
} `b]wyP  
catch(IOException e){e.printStackTrace ();} &R?to>xr\  
catch(Exception e){e.printStackTrace ();} 6H5o/)Q~  
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Utility.log(nFileLength); Y_n3O@,  
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return nFileLength; o 9/,@Ri\5  
} c5b}q@nH  
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32?'jRN(ue  
//保存下载信息（文件指针位置） / o I 4&W  
private void write_nPos() 1X5Yp|Ho  
{ NsSZ?ky  
try{ l|E4 7@#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5J|S
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output.writeInt(nStartPos.length); v'b%m8  
for(int i=0;i<nStartPos.length;i++) Tsj/alC[  
{ 1K<}  
// output.writeLong(nPos); w
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output.writeLong(fileSplitterFetch.nStartPos); $/tj<++W  
output.writeLong(fileSplitterFetch.nEndPos); 5pe)CjE:  
} v}a{nU'  
output.close(); ~:o$}`mW  
} kGo2R]Dd[  
catch(IOException e){e.printStackTrace ();} _$5DK%M}  
catch(Exception e){e.printStackTrace ();} w,vnpdT  
} I`rN+c:  
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KK2YT/K$SG  
//读取保存的下载信息（文件指针位置） !4=_l6kg~+  
private void read_nPos() ^v'0\(H?P  
{ G.~Q2O#T  
try{ REE.8_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !ehjLFS?_  
int nCount = input.readInt(); strM3j##x  
nStartPos = new long[nCount]; 2,`X@N`\  
nEndPos = new long[nCount]; $fT5Vc]B4  
for(int i=0;i<nStartPos.length;i++) f\_PNZCc  
{ 5N%d Les  
nStartPos = input.readLong(); K:$mEB[c<  
nEndPos = input.readLong(); #jG?{j3;?  
} ?k
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input.close(); v @0G^z|  
} 'TH[Db'`I  
catch(IOException e){e.printStackTrace ();} o:W*#dt
 
catch(Exception e){e.printStackTrace ();} ?%qaoxG37  
} e98QT9  
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q  
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private void processErrorCode(int nErrorCode) <N$Hb2b  
{ "0[`U(/  
System.err.println("Error Code : " + nErrorCode); a^@.C5  
} AG9DJ{T  
f_[dFKoX  
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//停止文件下载 ZvT,HJ0?  
public void siteStop() {d;z3AB  
{ +h+ 7Q'k  
bStop = true; l5Ko9CG  
for(int i=0;i<nStartPos.length;i++) aF+Lam(  
fileSplitterFetch.splitterStop(); y*{zX=]l<  
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} M'<% d[  
} zEtsMU  
//负责部分文件的抓取 aK;OzB)  
**FileSplitterFetch.java r(uo-/7z  
*/ oxN5:)  
package NetFox; N<a%l J  
XX%K_p`&Z  
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import java.io.*; dhLR#m30T  
import java.net.*; gjN'D!'E1D  
^@RvCJ+  
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public class FileSplitterFetch extends Thread { UCfouQCj  
W}TP(~x'N  
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String sURL; //File URL M(K7xx+G  
long nStartPos; //File Snippet Start Position P658 XKE  
long nEndPos; //File Snippet End Position mHW%:a\L  
int nThreadID; //Thread's ID 7`t"fS  
boolean bDownOver = false; //Downing is over _v0iH  
boolean bStop = false; //Stop identical E]/2u3p  
FileAccessI fileAccessI = null; //File Access interface .x,y[/[[)  
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' *a}*(0OA  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException CZu=/8?  
{ .#SgU<Wq  
this.sURL = sURL; 1~K'r&  
this.nStartPos = nStart; vbeE}7 *2  
this.nEndPos = nEnd; jIe /X]  
nThreadID = id; ~ E6e~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 n:/!{.  
}
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dt"/4wCO  
public void run() e( @</W  
{ %|}*xMQ  
while(nStartPos < nEndPos && !bStop) '#3FEo  
{ Y=G`~2Pr=  
x
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try{ W g7 eY'FE  
URL url = new URL(sURL); &(Fm@ksh\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
=O0A(ca"g  
httpConnection.setRequestProperty("User-Agent","NetFox"); Vlz\n  
String sProperty = "bytes="+nStartPos+"-"; Lg!E  
httpConnection.setRequestProperty("RANGE",sProperty); K=0xR*ll5  
Utility.log(sProperty); 4sQm"XgE  
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InputStream input = httpConnection.getInputStream(); Z8bg5%  
//logResponseHead(httpConnection); I]W7FZ=o  
7afG4 (<k  
U?f-/@fc  
byte[] b = new byte[1024]; 83Rs1}*  
int nRead; f|w;u!U(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) sGhw23  
{ Cfmd*,  
nStartPos += fileAccessI.write(b,0,nRead); e_Hpai<b  
//if(nThreadID == 1) !`?i>k?Q E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G-9i   
} 1]=X  
lPxhqF5pP  
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Utility.log("Thread " + nThreadID + " is over!"); J~WT;s  
bDownOver = true; +%\Ci!%b  
//nPos = fileAccessI.write (b,0,nRead); CqC )H7A  
} a5t&{ajJ  
catch(Exception e){e.printStackTrace ();} 8j70X <R  
} o"BED!/  
} NO[A00m|OL  
+&VY6(Zj+*  
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//打印回应的头信息 }YdC[b$j^  
public void logResponseHead(HttpURLConnection con) &2XH.$Q  
{ |=YK2};  
for(int i=1;;i++) vi^YtA  
{ _";w*lg}  
String header=con.getHeaderFieldKey(i); rrRv 7J&Q  
if(header!=null) 5?`4qSUz  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 
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Utility.log(header+" : "+con.getHeaderField(header)); LJ@(jO{z  
else +`Q]p"G  
break; "Tser*i )  
} 2@Yu:|d4U  
} .lb]Xa*n  
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public void splitterStop() q
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{ GNv{Ij<  
bStop = true; lBFKfLp&  
} q>BJ:_I i  
9:@Xz5  
{f`Y\_r$@  
} }WFI/W'  
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/* O DN
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**FileAccess.java
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*//文件访问(定位，写) t27UlFX  
package NetFox; 2c[HA  
import java.io.*; :tO4LEb  
zuN(~>YH  
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public class FileAccessI implements Serializable{ SS%Bde&<{  
]N]Fb3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9FSa=<0wE  
RandomAccessFile oSavedFile; QAxy?m,'  
long nPos; %XukiA+  
}(u:K}8  
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public FileAccessI() throws IOException kZ@UQ{>`  
{ wg0_J<y]  
this("",0); PUO7Z2  
} S>T ;`,  
+|dLR*s  
~
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public FileAccessI(String sName,long nPos) throws IOException )tJaw#Mih  
{ !Ltx2CB2]  
oSavedFile = new RandomAccessFile(sName,"rw"); )=}qAVO8  
this.nPos = nPos; &aIFtlC  
oSavedFile.seek(nPos); }G{"Mp4  
} Rq+7&%dy  
dF51_Kk  
~;$QSO\2h  
public synchronized int write(byte[] b,int nStart,int nLen) L3oL>r'|  
{ LqD7SJ}/f  
int n = -1; ?Ybq]J\q  
try{ ~fD\=- S1  
oSavedFile.write(b,nStart,nLen); DTA$,1JuD  
n = nLen; x f{`uHa8  
} 9O&gR46.  
catch(IOException e) R[\1Kk(Zo  
{ ^g(qPtQ  
e.printStackTrace (); jG&HPVr  
} m,kYE9{  
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8%;Wyqdf]  
return n; 30WOH 'n  
} 9teP4H}m  
hfIP   
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} V Zbn@1  
/"`hz6rIv  
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/* ,S dj"C  
**SiteInfoBean.java 6e\?%,H  
*/ 1qAE)8ie  
package NetFox; <ivG(a*=]  
LyvR].p=5*  
Xe&9|M  
public class SiteInfoBean { %`s#p` Ol1  
R%n*wGi_6b  
HFjSM~  
private String sSiteURL; //Site's URL 8*b{8%<K  
private String sFilePath; //Saved File's Path T&/n.-@nk  
private String sFileName; //Saved File's Name cz/E  
private int nSplitter; //Count of Splited Downloading File Q{S
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e}{#VB<  
*^; MWI  
public SiteInfoBean() M {'(+a[  
{//nSplitter的缺省值为5 ?;UR9f|!  
//default value of nSplitter is 5 QhRz57'  
this("","","",5); gzhIOeY  
} cZYvP  
*%jtcno=Y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ehB'@_y  
{ 6FUcg40Y  
sSiteURL= sURL; p8j4Tc5tQ>  
sFilePath = sPath; T.z efoZ  
sFileName = sName; 1(T2:N(M-A  
this.nSplitter = nSpiltter; *[ 0,QEy  
71E~~$  
0s//&'*Q  
} $'>iNMtK{p  
.?APDr"QQH  
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public String getSSiteURL() <tZtt9j_  
{ ?m5"|f\  
return sSiteURL; 'z}9BGR!  
}  Z
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4w9=z,  
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public void setSSiteURL(String value) W.{+0xx  
{ H~#$AD+H  
sSiteURL = value; U9PI#TX &O  
} uAnL`
 
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v~AshmP  
public String getSFilePath() k t!@}QP  
{ I_Lm[  
return sFilePath; :/SGB3gb1t  
} xv147"w'v  
p)Q5fh0-  
)Z4iM;4]  
public void setSFilePath(String value) {G3Ok++hc  
{ 5ad@}7&  
sFilePath = value; _-{=Z=?6}  
} 1+3-Z>^e  
3TjyKB *!  
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public String getSFileName() :8bq0iqsV  
{ \>"Zn7  
return sFileName; X xwcvE  
} cCZ$TH  
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4@F8-V3q4  
public void setSFileName(String value) ->{\7|^  
{ #%$@[4"V  
sFileName = value; YVF@v-v-,  
} [Pq |6dz  
>2K'!@~'  
3zfpFgD!  
public int getNSplitter() n87Uf$  
{ s+ *LVfau  
return nSplitter; mV"F<G; H  
} v#g:]T  
U. <c#S  
Hxac#(,7  
public void setNSplitter(int nCount) &a\w+  
{ &'/PEOu&}G  
nSplitter = nCount; rcLF:gd]E  
} +DefV,Ny  
} $u,A/7\s  
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/* &q-P O  
**Utility.java ,=@WE>ip  
*/ d8 v9[4  
package NetFox; )9/i
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%(%EEt  
]{|l4e4P  
public class Utility { w0=/V[fs  
\zA3H$Df~  
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public Utility() &,Rye Q  
{ 7?_gm>]a  
k&K'FaM!  
{<Y!'WL{  
} 1 Cz}|#U  
eUu<q/FUMj  
//线程睡眠 ~(c<M>Q8  
public static void sleep(int nSecond) :SMf (E 5  
{ J7EWaXGbz  
try{ O]="ggq&  
Thread.sleep(nSecond); =NK'xPr  
} &jnBDr  
catch(Exception e) P()&?C  
{ rnMi >?  
e.printStackTrace (); n sN n>{  
} a|d
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} VyIJ)F.c  
K-.%1d@$y  
//日志 Q0ezeo  
public static void log(String sMsg) 0iMfyW:  
{ C^]UK  
System.err.println(sMsg); PK{FQ3b2{  
} )P+<=8@a  
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F2n4#b  
public static void log(int sMsg) t >64^nS  
{ .[:WMCc\  
System.err.println(sMsg); nhm#_3!6A  
} fpzEh}:H\  
} (YPG4:[  
4eaH.&&  
3s*mq@~1X  
/* b?M. 0{"H  
**TestMethod.java D iHj!tZN  
*/ ^h`rA"F\  
package NetFox; Hp(41Eb,  
:q2RgZE  
5Ktll~+:#  
public class TestMethod { - ikq#L){  
:de4Fje/4y  
n34d"l3  
public TestMethod() h^{aG])  
{ ///xx/weblogic60b2_win.exe I[06R
 
try{ 2of+KI:
 
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Dn>C :YS`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `X=[ m>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); s9u7zqCF  
fileFetch.start(); E%f!SD  
} $S/WAw,/  
catch(Exception e){e.printStackTrace ();} !.q#X^@>L  
wv%
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ph~#{B(\  
} 0J5$ Yw1'F  
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PIsXX#`7;  
public static void main(String[] args) 4!M0)Nix  
{ `RqV\ 6G+  
new TestMethod(); 0V2~  
} h9. Yux  
} q}"HxMJ  
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