http断点续传简单实现（java)

/* :Fe}.* t  
**SiteFileFetch.java $\:;N]Cs~0  
*/ v?\Z4Z|f  
package NetFox; zQpF,N<b  
import java.io.*; Ct-^-XD  
import java.net.*; g<ZB9;FX %  
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public class SiteFileFetch extends Thread { WS17DsWW  
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SiteInfoBean siteInfoBean = null; //文件信息Bean J0{;"
 
long[] nStartPos; //开始位置 b/>L}/^PM  
long[] nEndPos; //结束位置 J['pBlEb\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F#<$yUf%  
long nFileLength; //文件长度 14U:.
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boolean bFirst = true; //是否第一次取文件 IEbk_-h[  
boolean bStop = false; //停止标志 B!>hHQ2  
File tmpFile; //文件下载的临时信息 ?<mxv"  
DataOutputStream output; //输出到文件的输出流 }q-*Ls~  
V4~`yT?*"  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） gaBVD*>  
public SiteFileFetch(SiteInfoBean bean) throws IOException .(D,CGtYb  
{ gK8E|f-z  
siteInfoBean = bean; S5a?KU
  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ?g7O([*[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); E@uxEF  
if(tmpFile.exists ()) iLd_{  
{ ~hx__^]d  
bFirst = false; mpcO-%a  
read_nPos(); g!<=NVhYt  
} ;:
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else ZA1u  
{
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nStartPos = new long[bean.getNSplitter()]; <G+IbUG:  
nEndPos = new long[bean.getNSplitter()]; K<#Q;(SFU  
} ~Vh< mt  
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} \xtY\q,[  
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public void run() Qv v~nGq$  
{ Aw7oyC!  
//获得文件长度 /b ]Yya#  
//分割文件 cN]e{|  
//实例FileSplitterFetch _s(izc  
//启动FileSplitterFetch线程 5(+9( \x  
//等待子线程返回 @d/Wa=K  
try{ JZc"4qf@OT  
if(bFirst) R:[IH2F s  
{ RxeyMNd  
nFileLength = getFileSize(); -c_}^j  
if(nFileLength == -1) xzI?'?duC  
{ mmf}6ABYT  
System.err.println("File Length is not known!"); XkGS3EY  
} .YYLMI  
else if(nFileLength == -2) J.t tJOP  
{ =zetZJg  
System.err.println("File is not access!"); 0vi)my;!  
} j B.ZF7q  
else n#
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{ N51g<K  
for(int i=0;i<nStartPos.length;i++) b@p3iq:  
{ VH>?%aL  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =&9x}4`;%  
} il403Ae0  
for(int i=0;i<nEndPos.length-1;i++) Zo12F**{  
{ -JMlk
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nEndPos = nStartPos[i+1]; j$%uip{  
} czp
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nEndPos[nEndPos.length-1] = nFileLength; K1*oYHB  
} v \xuq`  
} QOfqW@g  
X{-@3tG<r  
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//启动子线程 _,G^#$pH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Y<h [5  
for(int i=0;i<nStartPos.length;i++) [UW%(N  
{ dI$U{;t  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H.H$5(?O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IegZ)&_n  
nStartPos,nEndPos,i); JGZxNUr^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +DpiX&^h   
fileSplitterFetch.start(); 6`V2-zv$  
} li`4&<WG
C  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3Mlwq'pzD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vwc)d{ND  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "i5Rh^  
nEndPos = " + nFileLength); fc,^H&
 
// fileSplitterFetch[nPos.length-1].start(); zA<Hj;9SM  
<D1>;C  
_7^4sR8=  
//等待子线程结束 d^.@~  
//int count = 0; kN'.e*  
//是否结束while循环 KcW]"K>p!  
boolean breakWhile = false; r6x
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while(!bStop) q|EE em  
{ '9w.~@7  
write_nPos(); kr=&x)Wy!  
Utility.sleep(500); 4!3mSWNV  
breakWhile = true; |IgH0 zZ  
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for(int i=0;i<nStartPos.length;i++) 6q8b>LG|  
{ \_#Z~I{  
if(!fileSplitterFetch.bDownOver) 5Vj t!%?r  
{ fNh0?/3)  
breakWhile = false; YtWO=+rX  
break; \i}:Vb(^  
} Wu\szI"  
} |J_kS90=  
if(breakWhile) m:sT)  
break; p2\mPFxEP  
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//count++; j)vfI>  
//if(count>4) 1~|o@CO  
// siteStop(); 5|pPzEA>  
} %YhM?jMW  
>h>  
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System.err.println("文件下载结束！"); 1638U1  
} HpQuro'Qh  
catch(Exception e){e.printStackTrace ();} 4|EV`t}EV  
} "T?hIX/p_  
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*w/})Y3^  
//获得文件长度 cc %m0p  
public long getFileSize() ~|>q)4is6a  
{ ":G\  
int nFileLength = -1; 'Drz6K_KrP  
try{ kM>Bk\  
URL url = new URL(siteInfoBean.getSSiteURL()); {)c2#h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 42If/N?  
httpConnection.setRequestProperty("User-Agent","NetFox"); c[n4{q1  
7E}.P1  
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int responseCode=httpConnection.getResponseCode(); N-
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if(responseCode>=400) 3<L>BakD  
{ Mjr19_.S  
processErrorCode(responseCode); *$4EXwt'  
return -2; //-2 represent access is error GCEcg&s=\S  
} :K#z~#n  
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String sHeader; (oKrIm  
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for(int i=1;;i++) b_p/ 1W:  
{ yN4K^#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7"iUyZ(  
//Utility.log(in.readLine()); Oapv`Z\i~  
sHeader=httpConnection.getHeaderFieldKey(i); GIyb0XjTw  
if(sHeader!=null) 9|}u"jJB%E  
{ eOdB<He36  
if(sHeader.equals("Content-Length")) [
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{ Z^'i16  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); yGN2/>]  
break; K< ;I*cAX  
} B_u1FWc  
} d8o<Q 9  
else qMj
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break; $XOs(>~"r  
} <EHgPlQn  
} Pm Zb!|  
catch(IOException e){e.printStackTrace ();} X,Q'Xe/  
catch(Exception e){e.printStackTrace ();} 1_aUU,|.  
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Utility.log(nFileLength); 2(<2Gnpl  
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return nFileLength; 04u^Q  
} Yr\pgK,  
WLB@]JvTBY  
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//保存下载信息（文件指针位置） f7mN,_Lt  
private void write_nPos() -F+ )N$CW  
{ &:3uK`  
try{ LMF@-j%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )rqb<O  
output.writeInt(nStartPos.length); bu j}pEI  
for(int i=0;i<nStartPos.length;i++) 9MI~yIt`L  
{ M`~UH\  
// output.writeLong(nPos); g<@P_^vo  
output.writeLong(fileSplitterFetch.nStartPos); ^5:x
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output.writeLong(fileSplitterFetch.nEndPos); 2Gw2k8g&  
} @`,~d{ziF  
output.close(); )U?O4| \P  
} D (>,#F  
catch(IOException e){e.printStackTrace ();} Tf|?j=f  
catch(Exception e){e.printStackTrace ();} V^  
} Xqz\%&G  
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//读取保存的下载信息（文件指针位置） Hw(_l,Xf  
private void read_nPos() "k0bj>  
{ =FB[<%  
try{ l[_y|W5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); a&?SRC'x  
int nCount = input.readInt(); vzr?#FG  
nStartPos = new long[nCount]; Vg>\@ C.s  
nEndPos = new long[nCount]; #%=6DHsK  
for(int i=0;i<nStartPos.length;i++) ;g:!WXd  
{ Q"@x,8xW  
nStartPos = input.readLong(); _yu d  
nEndPos = input.readLong(); =tS1|_  
} 0pC}+ +  
input.close(); 9}=]oX!+V  
} ;F/yS2p  
catch(IOException e){e.printStackTrace ();} 323zR*\m  
catch(Exception e){e.printStackTrace ();} cg]\R1Gm  
} d&@>P&AT  
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private void processErrorCode(int nErrorCode) 8n[6BF);  
{ 'pa>;{  
System.err.println("Error Code : " + nErrorCode); W`qiPLk  
} G~ldU: ?  
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h8
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//停止文件下载 Y%i=u:}fm  
public void siteStop() ;`{PA !>  
{ %/K'VE6pb  
bStop = true; fW'@+<b  
for(int i=0;i<nStartPos.length;i++) C,;hNg[  
fileSplitterFetch.splitterStop(); ]z
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} kwcH$w<I  
} "\n,vNk  
//负责部分文件的抓取 0c$0<2D%  
**FileSplitterFetch.java 0Bo7EV  
*/ ?tf/#5t}  
package NetFox; ;j#(%U]Vp  
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import java.io.*; 6<uJ}3  
import java.net.*; 8@}R_GZc  
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public class FileSplitterFetch extends Thread { {x-iBg9#l2  
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String sURL; //File URL TSl:a &  
long nStartPos; //File Snippet Start Position L,m'/}$  
long nEndPos; //File Snippet End Position Y/3CB  
int nThreadID; //Thread's ID tfSY(cXg'T  
boolean bDownOver = false; //Downing is over &EELq"5K  
boolean bStop = false; //Stop identical "5 /i  
FileAccessI fileAccessI = null; //File Access interface iq25|{1$  
&V.\Svm8]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }k`-n32)|  
{ 
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this.sURL = sURL; ~_!lx  
this.nStartPos = nStart; |#&{`3$CG[  
this.nEndPos = nEnd; X J+y5at  
nThreadID = id; pBd_BaN  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /|kR=
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} \A{ [2  
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public void run() P ,%IZ.  
{ fAW(  
while(nStartPos < nEndPos && !bStop) *FINNNARB  
{ efc<lSUR  
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try{ C\Y%FTS:  
URL url = new URL(sURL); h~!KNF*XW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \z~wm&  
httpConnection.setRequestProperty("User-Agent","NetFox"); @
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String sProperty = "bytes="+nStartPos+"-"; o~aK[   
httpConnection.setRequestProperty("RANGE",sProperty); ZQ%4]=w  
Utility.log(sProperty); z]^u@]@NC  
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InputStream input = httpConnection.getInputStream(); sDylSYq  
//logResponseHead(httpConnection); j,]KidDWm  
 1\[En/6  
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byte[] b = new byte[1024]; B7*^rbI:X  
int nRead; h()Ok9]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) oPqWL9]  
{
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nStartPos += fileAccessI.write(b,0,nRead); ;fdROI  
//if(nThreadID == 1) !LG 5q/}&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6>fQe8Y  
} IbC8DDTD  
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Utility.log("Thread " + nThreadID + " is over!"); @hb K  
bDownOver = true; DX*eN"z[  
//nPos = fileAccessI.write (b,0,nRead); rz@FUU:&  
} $jc&Tk#  
catch(Exception e){e.printStackTrace ();} dN8@ 0AMSf  
} LU=<?"N6  
} *hk8[  
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//打印回应的头信息 -$x5[6bN  
public void logResponseHead(HttpURLConnection con) ;Nd,K C0k  
{ r?:zKj8/u  
for(int i=1;;i++) nn1
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{ /"f4aF[  
String header=con.getHeaderFieldKey(i); qwERy{]Sp;  
if(header!=null) #835$vOe  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 37F&s  
Utility.log(header+" : "+con.getHeaderField(header)); %u)niY-g
 
else wWaJ%z>3y  
break; K[.*8  
} o>#ue<Bc6  
} "B$r{ vG  
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public void splitterStop() wa)E.(x  
{ [!<W{ ($5  
bStop = true; M9t`w-@_w  
} ::lD7@Wg  
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} gf&\)"  
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v  
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/* ;b-d2R  
**FileAccess.java .8v[ss6:  
*//文件访问(定位，写) iE}Lw&x  
package NetFox; fH>I/%  
import java.io.*; jNC@b>E?~  
qgk-[zW#  
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public class FileAccessI implements Serializable{ (FY<%.Pa  
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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 @[s+5_9nk  
RandomAccessFile oSavedFile; Yp;6.\Z8[  
long nPos; k*U(ln  
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public FileAccessI() throws IOException KysJ3G.k
\  
{ )J"*[[e  
this("",0); >$g+Gx\v4  
} |)4aIa  
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public FileAccessI(String sName,long nPos) throws IOException ^@4$O|3Wh'  
{ H[u
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oSavedFile = new RandomAccessFile(sName,"rw"); #C`IfP./  
this.nPos = nPos; m|c5X)}-  
oSavedFile.seek(nPos); -!ARVf *  
} Q&@~<!t  
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public synchronized int write(byte[] b,int nStart,int nLen)  g%.;ZlK  
{ egd%,`  
int n = -1; fl4z'8P"(  
try{ ij|+MX  
oSavedFile.write(b,nStart,nLen); ; *@lH%u  
n = nLen; NCKhrDd&  
} xc&&UKd  
catch(IOException e) @j{n V@|  
{ i:@n6GW+iw  
e.printStackTrace (); "h84D&V  
} G(*7hs  
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return n; VOa7qnh4:[  
} #K4lnC2qz  
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} B.T|e,g26  
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/* h%0FKi^  
**SiteInfoBean.java ,iy;L_N  
*/ Z'V"nhL  
package NetFox; y?}R,5k  
/ Ml d.  
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public class SiteInfoBean { iDdmr32E  
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private String sSiteURL; //Site's URL P*kKeM
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private String sFilePath; //Saved File's Path DH*=IzcJf  
private String sFileName; //Saved File's Name vp_$Ft-R  
private int nSplitter; //Count of Splited Downloading File R3<2Z0lqy  
$YPQi.  
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public SiteInfoBean() jWX^h^
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{//nSplitter的缺省值为5 :8CYTEc  
//default value of nSplitter is 5 Ev)a
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this("","","",5); {T=rsPp<@  
} )yyS59s  
7k==?,LG3  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6tDCaB  
{ _XP3|E;I/  
sSiteURL= sURL; ,<cF<9h  
sFilePath = sPath; l0sBXs`3b  
sFileName = sName; /Sn>{ &  
this.nSplitter = nSpiltter; ]ICBNJ  
4hLv"R.  
/qeSR3WC  
} 0D=7Mef  
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public String getSSiteURL() `BGU   
{ a=%QckR*  
return sSiteURL; n~e#Y<IP\1  
} ,iYKtS3  
;A3aUN;"I  
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public void setSSiteURL(String value) M%#H>X\/  
{ |TE\]  
sSiteURL = value; 6Y-sc*5  
} SaA9)s  
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public String getSFilePath() zm9_[0  
{ KJ]ejb$  
return sFilePath; mm@)uV<\  
} zr1,A#BV  
uV'w0`$y  
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public void setSFilePath(String value) J@4,@+X  
{ HbUadPr  
sFilePath = value; $S(q;Y  
} ]L?DV3N  
(!iGQj(m  
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public String getSFileName() p#T^o]+  
{ "v9i;Ba>+  
return sFileName; YJ[Jo3M@j0  
} c~=yD:$  
0s%rd>3  
}F
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public void setSFileName(String value) A!\-e*+W=  
{ GSh~j-C'  
sFileName = value; 4-dV%DgC  
} {k#RWDespy  
4\?GA`@  
C $r]]MSj  
public int getNSplitter() G'\x9%  
{ ?t{ 2y1  
return nSplitter; TzW1+DxM5  
} $[NC$*N7  
:+nECk 
 
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public void setNSplitter(int nCount) hG3p"_L  
{ EgY yvS)  
nSplitter = nCount; J BN_Upat  
} }s7ibm'  
} -Jj"JN.  
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C*f3PB=H_  
/* 'r2VWavT  
**Utility.java #FHyP1uyc  
*/ PM A61g  
package NetFox; s,2gd'  
\a|bx4M  
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public class Utility { e[8AdE  
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public Utility() J% t[{  
{ *Pmk1h2  
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L
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} =rrbS8To=  
9j6  
//线程睡眠 ny,a5zEnF  
public static void sleep(int nSecond) ^:yg,cS|Be  
{ pOz
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try{ *YI>Q@F9  
Thread.sleep(nSecond); D#~S<>u@  
} <g^!xX<r?  
catch(Exception e) Owa]ax5  
{ 3?"JFfYU,'  
e.printStackTrace (); 
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} >cEB,@~  
} D}| 30s?u1  
q[}[w!to  
//日志 b)eKa40Z  
public static void log(String sMsg) )L%i"=<Bdy  
{ R4RSXV  
System.err.println(sMsg); MDo4{7  
} hSvA dT]m  
O+o4E?}  
bLHj<AX#>|  
public static void log(int sMsg) #{t?[JUn  
{ 6,C,LT2^(  
System.err.println(sMsg); Nd"Rt  
} gmY*}d` 'f  
} p=U/l#xO  
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cVR3_e{&H  
/* =>0+BD  
**TestMethod.java #]@<YKoV{  
*/ <Rl:=(]i~  
package NetFox; V`n;W6Q17  
-UPl
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3]X9 z  
public class TestMethod { Jhyb{i8RR  
&d`z|Gx9  
4rh*&'  
public TestMethod() B3P#p^  
{ ///xx/weblogic60b2_win.exe LE|*Je3a  
try{ 7sQw&yUL)  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); B~0L'8WzW  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); g]z[!&%Ahs  
SiteFileFetch fileFetch = new SiteFileFetch(bean); iZVMDJ?(Z]  
fileFetch.start(); U~mv1V
^.  
} mh#dnxeR  
catch(Exception e){e.printStackTrace ();} sp0j2<$a  
CFW\  
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} w :w  
+!I7(gL  
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public static void main(String[] args) $=c79Al
(  
{ +n ${6/  
new TestMethod(); }^Unx W  
} e%v<nGN.-  
} jDp]}d|f)  
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