http断点续传简单实现（java)

/* 7wsn8_n9  
**SiteFileFetch.java 9D:p~_"g  
*/  k'X v*U  
package NetFox; Zf |%t  
import java.io.*; " 4#V$V  
import java.net.*; 1HG~}E  


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public class SiteFileFetch extends Thread { 5BCXI8Ox9x  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~U#afGH$  
long[] nStartPos; //开始位置 AzVON#rj  
long[] nEndPos; //结束位置 kDS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >S3iP?V7  
long nFileLength; //文件长度 9S@PY_ms  
boolean bFirst = true; //是否第一次取文件 6Yebc_, R  
boolean bStop = false; //停止标志 eKNZ?!c=  
File tmpFile; //文件下载的临时信息 :}0y[qc3  
DataOutputStream output; //输出到文件的输出流 jKZJ0`06q  
"tB"C6b  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BB5(=n+  
public SiteFileFetch(SiteInfoBean bean) throws IOException .t''(0_kC  
{ `;4P?!WG  
siteInfoBean = bean; Ro$'|}(+A  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4G0Er?D   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =4uL1[0'  
if(tmpFile.exists ()) *Hy-D</w%  
{ Lt0JUUa0  
bFirst = false; pb1/HhRR^n  
read_nPos(); TaeN?jc5  
} "Q6oPDX(  
else MZ o\1tU-i  
{ z=B*s!G  
nStartPos = new long[bean.getNSplitter()]; $^?"/;8P5  
nEndPos = new long[bean.getNSplitter()]; Ehu^_HZ  
} nIJ2*QJ  
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} ^{nf0)56c  
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public void run() js)M c*]&  
{ %719h>$  
//获得文件长度 -jdS8n4  
//分割文件 L\}o(P(  
//实例FileSplitterFetch .'JO7of  
//启动FileSplitterFetch线程 _Q,`Qn@|BD  
//等待子线程返回 fqA\Rp6Z  
try{ j'FSd*5m  
if(bFirst) ;rYL\`6L  
{ 1=gE,k5H  
nFileLength = getFileSize(); rk:^^r>5Qi  
if(nFileLength == -1) F|3Te?_  
{ yEIM58
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System.err.println("File Length is not known!"); YKKZRlQo  
} hRTw8-wy:  
else if(nFileLength == -2) w%R(*,r6  
{
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System.err.println("File is not access!"); @igr~hJ  
} .Nz2K[  
else S0\QZ/je  
{ U8qb2'a8  
for(int i=0;i<nStartPos.length;i++) U;u
@\E@2  
{ ~kPHf_B;z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]W39HL  
} $q,2VH:Ip  
for(int i=0;i<nEndPos.length-1;i++) -qaJ@T+J+7  
{ 5H#f;L\k  
nEndPos = nStartPos[i+1]; \=PnC}
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} }M-^A{C\%  
nEndPos[nEndPos.length-1] = nFileLength; #'[4k:  
} =aZgq99  
} N,fEta6  
&7_xr.c7  
/ r6^]grg  
//启动子线程
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; W5 ^eCYHoi  
for(int i=0;i<nStartPos.length;i++) r:0F("},  
{ z5`AJrj%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *Z'*^Y1le  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), V .+ mK|)  
nStartPos,nEndPos,i); 4H'\nsM  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x9Um4!/t  
fileSplitterFetch.start(); l#u$w&  
} xa#;<8 iV  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), EYWRTh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); y,'M3GGl  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0N.B=j|  
nEndPos = " + nFileLength); :bt;DJ@  
// fileSplitterFetch[nPos.length-1].start(); Em8q1P$tm>  
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#4UK
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//等待子线程结束 mU@pRjq=  
//int count = 0; k|V%*BvY>  
//是否结束while循环 Nki08qZ[  
boolean breakWhile = false; tNP>6F/  
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while(!bStop) M ,!Dhuas  
{ 7L3:d7=MIW  
write_nPos(); [`pp[J-~7  
Utility.sleep(500); sZ,xbfZby  
breakWhile = true; 8Ld{
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<&JK5$l<X  
for(int i=0;i<nStartPos.length;i++) \cJ?2^Eq  
{ Sd[%$)scC  
if(!fileSplitterFetch.bDownOver) tNpBRk(}  
{ u~b;m  
breakWhile = false; oA/[>\y  
break; LFvO[&  
} v'3.`aZ!  
} i/U
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if(breakWhile) J:W|2U="  
break; E%Tpby}^'  
 W^dk:  
})#VO-J  
//count++; u NmbR8Mx  
//if(count>4) Ub[SUeBGH  
// siteStop(); 7\(mn$  
} :c75*h`  
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fv@mA--  
System.err.println("文件下载结束！"); 3an9Rb V  
} YA+jLy6ZL  
catch(Exception e){e.printStackTrace ();} 9ZXkuP9vm  
} \vg(@)$q   
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LAs#g||M  
//获得文件长度 @6["A'h  
public long getFileSize() 4)Jtc2z7Z\  
{ c_V^~hq  
int nFileLength = -1; j8Pqc]  
try{ CG#lpAs  
URL url = new URL(siteInfoBean.getSSiteURL()); srS2v\1:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rF@njw@  
httpConnection.setRequestProperty("User-Agent","NetFox"); /;5U-<qf  
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int responseCode=httpConnection.getResponseCode(); 4Fu:ov ]M  
if(responseCode>=400) h D5NX  
{ h2S!<  
processErrorCode(responseCode); TA4>12C6  
return -2; //-2 represent access is error 5:R$xgc  
} Zc!rL0
T  
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5r2A^<)  
String sHeader; mYUR(*[  
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for(int i=1;;i++) 8Cx6Me>,=  
{ q\DN8IJ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); YL?2gBT  
//Utility.log(in.readLine()); 5& 2([  
sHeader=httpConnection.getHeaderFieldKey(i); 7Gh+EJJ3I  
if(sHeader!=null) KUD.hK.  
{ _BFDsQ  
if(sHeader.equals("Content-Length")) WHF[l1  
{ MiK -W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); gDN7ly]6M  
break; ~`Y!_'(x  
} 1j_gQ,'20  
} }yzCq+
  
else QG1+*J76b@  
break; !l(D0 C  
} ?8U#,qq#`  
} s7d4)A%  
catch(IOException e){e.printStackTrace ();} B3^F $6=  
catch(Exception e){e.printStackTrace ();} T0;8koj^_  
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Utility.log(nFileLength); '^|u\$&U  
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return nFileLength; :~^_*:  
} vZiuElxKi  
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//保存下载信息（文件指针位置） W5*Kq^6Pd  
private void write_nPos() b)+;=o%  
{ w!%"b03q  
try{ 4j1$1C{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :{LNr!I?I  
output.writeInt(nStartPos.length); \:BixBU7  
for(int i=0;i<nStartPos.length;i++) \; voBU  
{ eae`#>XP  
// output.writeLong(nPos); $xU)t&Df
 
output.writeLong(fileSplitterFetch.nStartPos); En9>onJ  
output.writeLong(fileSplitterFetch.nEndPos); `VrQ?s  
} O7"16~a  
output.close(); 56?RFnZ&j  
} %f?Z/Wn  
catch(IOException e){e.printStackTrace ();} fsjCu!  
catch(Exception e){e.printStackTrace ();} y9Q#%a8V  
} ~tc,p  
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b!<\#[ A4  
//读取保存的下载信息（文件指针位置） drQI@sPp  
private void read_nPos() .fgVzDR|+  
{ >~;= j~  
try{ V8hmfV~=]P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F$j?}  
int nCount = input.readInt(); G"F)t(iX  
nStartPos = new long[nCount]; g-~]^$  
nEndPos = new long[nCount]; ^'ws/(  
for(int i=0;i<nStartPos.length;i++) h-<Qj,L{W  
{ "
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nStartPos = input.readLong(); /jl/SV+  
nEndPos = input.readLong(); Pihpo  
} J#DN2y<  
input.close(); )Drif\FF)  
} H?_wsh4J  
catch(IOException e){e.printStackTrace ();} #|"M  
catch(Exception e){e.printStackTrace ();} (zX75QSKV  
} *!.anbo@?z  
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private void processErrorCode(int nErrorCode) |{ @BH  
{ z*)kK  
System.err.println("Error Code : " + nErrorCode); N(l  
} $DlO<  
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r>ag(^J\  
//停止文件下载 =[:pm)  
public void siteStop() iv ~<me0F  
{ 7O-fc1OTv  
bStop = true; P~*'/!@  
for(int i=0;i<nStartPos.length;i++) a$5
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fileSplitterFetch.splitterStop(); x#XxD<y  
G ?Hx"3:?  
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} +O)Y7k{?C5  
} ?="?)t[  
//负责部分文件的抓取 ZY|$[>X!  
**FileSplitterFetch.java W)<t7q+  
*/ $-p9cyk  
package NetFox; feJl[3@tO  
!'#GdRstv  
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import java.io.*; ||))gI`3a  
import java.net.*; #}lWM%9Dy  
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public class FileSplitterFetch extends Thread { h])oo:u'/Q  
-%dBZW\u2  
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String sURL; //File URL s6QD^[  
long nStartPos; //File Snippet Start Position P*]hXm85[K  
long nEndPos; //File Snippet End Position A">R-1R  
int nThreadID; //Thread's ID P]O=K  
boolean bDownOver = false; //Downing is over &I:ZJuQ4  
boolean bStop = false; //Stop identical OtbPrF5  
FileAccessI fileAccessI = null; //File Access interface ^fQa whub  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException w6h*dh$w  
{ IgN^~ag`  
this.sURL = sURL; ;Z9(ll:<$  
this.nStartPos = nStart; )b1X6w[  
this.nEndPos = nEnd; J$U_/b.mk  
nThreadID = id; \YSprXe  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1H?I?IT30  
} w*]FJ-b<.j  
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public void run() 6ZAZJn|  
{ PQ{5*}$N  
while(nStartPos < nEndPos && !bStop) Ciy%7_~\  
{ q+} \(|  
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try{ uu.}<VM.1  
URL url = new URL(sURL); ?r{hrAx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fB 0X9iV6j  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6OB3%R'p  
String sProperty = "bytes="+nStartPos+"-"; h\2iArw8  
httpConnection.setRequestProperty("RANGE",sProperty); g;Zy3   
Utility.log(sProperty); kA> e*6  
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InputStream input = httpConnection.getInputStream(); 9o4h~Imu  
//logResponseHead(httpConnection); "}Ikx tee  
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byte[] b = new byte[1024]; 6Jq3l_  
int nRead; I
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R9(Yi<CC  
{ Dr76+9'i  
nStartPos += fileAccessI.write(b,0,nRead); JLt%G^W>  
//if(nThreadID == 1) ]57yorc`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0gGr/78   
} ;XQ27,K&  
!zsrORF{  
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Utility.log("Thread " + nThreadID + " is over!"); CvR-lKV<  
bDownOver = true; %@:6&  
//nPos = fileAccessI.write (b,0,nRead); |+KwyHE`9  
} ?\)h2oi!F5  
catch(Exception e){e.printStackTrace ();} %E"v@  
} {VXucGI|  
} 2liJ^ `  
G
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//打印回应的头信息 [RF
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public void logResponseHead(HttpURLConnection con) |?]doBm|  
{ VkO*+"cGv  
for(int i=1;;i++) Abi(1nXdQ  
{ m\XG7uo~  
String header=con.getHeaderFieldKey(i);
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if(header!=null) . :>e"D  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #WJ*)$A@&  
Utility.log(header+" : "+con.getHeaderField(header));
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else ef)zf+o  
break; LlS~J K  
} 2[;~@n1P  
} ,p#r; O<O  
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public void splitterStop() !Qf*d;wxn(  
{ i"=lxqWeaV  
bStop = true; dWY{x47  
} m@u%3*:  
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} +KD7Di91<K  
;4(}e{  
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/* j@w1S[vt  
**FileAccess.java :`Ep#[Wvo  
*//文件访问(定位，写) Br15S};Ce  
package NetFox; z{FFTb^B  
import java.io.*; 2Y<]X7Ch:  
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;TS%e[lFhQ  
public class FileAccessI implements Serializable{ #vhN$H:&q  
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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 q3#+G:nh  
RandomAccessFile oSavedFile; (Q @'fb9z  
long nPos; x$bUd 9  
r/HCWs|  
7(oA(l1V  
public FileAccessI() throws IOException VX82n,'=t  
{ TVx `&C+  
this("",0); "wuO[c&%/  
} jd,i=P%  
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fm`
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public FileAccessI(String sName,long nPos) throws IOException A)
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{ 01n132k  
oSavedFile = new RandomAccessFile(sName,"rw"); y4LUC;[n  
this.nPos = nPos; ggiy{CdR  
oSavedFile.seek(nPos); <9piKtb|L  
} lSW'qgh  
IM7<z,*oF  
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public synchronized int write(byte[] b,int nStart,int nLen) *z)gSX  
{ i;U*Y *f  
int n = -1; "M!m-]  
try{ 1+WVh7gF  
oSavedFile.write(b,nStart,nLen); 5 7t.Ud  
n = nLen; w/(c}%v}=  
} )dqNN tS  
catch(IOException e) mJ=V<_  
{ \wk;Bo  
e.printStackTrace (); =JgR c7  
} R ZQH#+*t}  
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return n; <+-n lK4  
} z<mN-1PM7&  
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} N0Y4m_dm*  
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/* VXWV Pj#  
**SiteInfoBean.java u~j H  
*/ R:YV
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package NetFox; FZ?eX`,  
!C05;x8{  
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public class SiteInfoBean { i9XpP(mf  
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private String sSiteURL; //Site's URL MO0NNVVi%U  
private String sFilePath; //Saved File's Path Y`(Ri-U4  
private String sFileName; //Saved File's Name u*;H$&  
private int nSplitter; //Count of Splited Downloading File Wm`*IBWA  
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!?0C(VL(:  
public SiteInfoBean() jhQoBC>:  
{//nSplitter的缺省值为5 =>`zk^  
//default value of nSplitter is 5 'JJKnE zQ  
this("","","",5); ~{tO8 ]  
} DE?k|Get2  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _^#eO`4"  
{  IPK1g3Z  
sSiteURL= sURL; xh$yXP0/  
sFilePath = sPath; wCg7JW#  
sFileName = sName; $%MgIy  
this.nSplitter = nSpiltter; S-q"'5>  
t#|R"Q#  
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} *c[
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public String getSSiteURL() yzp#  
{ r8:"\%"f>  
return sSiteURL; !zF07.(E  
} 5l1R")0`t_  
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public void setSSiteURL(String value) 4Ii5V c  
{ '(3 QyCD  
sSiteURL = value; IRx%L?  
} 7$Z_'GJ]1C  
5(J?C-Pk  
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public String getSFilePath() ,o%by5j"^N  
{ V~j^   
return sFilePath; OxGfLeP.R!  
} >fI\f <ez  
1b3k|s4   
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public void setSFilePath(String value) p03I&d@w>  
{ g:)iEw>a  
sFilePath = value; LX7P?j  
} |~ fI=1;;x  
te-xhJ&K  
+] ;WN  
public String getSFileName() 6`Tx meIP  
{ 3=sBe H
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return sFileName; 3`%E;
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} %'s_=r`  
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YZ+G7D>  
public void setSFileName(String value) h>D;QY  
{ trwQ@7  
sFileName = value; EA>.SSs!  
} >9A18xC  
C{85#`z`  
sED"}F)  
public int getNSplitter() (FApkvy  
{ c86KDEF  
return nSplitter; uq s   
} zu{K"7Bx  
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y*+8Z&i.:  
public void setNSplitter(int nCount) 81:%Z&?vRl  
{ w=;>  
nSplitter = nCount; "NLuAB.P  
} SgewAng?@o  
} .(q'7Q Z/  
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/* O)vGIp?f't  
**Utility.java L5I!
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*/ 02t({>`  
package NetFox; 4;Ucas6  
E
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public class Utility { 56<UxIa~  
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public Utility() uxD3+Q  
{ Gh=I2GSo  
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} bl a`B=r  
w6!97x  
//线程睡眠 mW'3yM  
public static void sleep(int nSecond) 6H'A]0  
{ r+C4<-dT  
try{ z8t;jw  
Thread.sleep(nSecond); %Hd[,duwO  
} Ez|NQ:o  
catch(Exception e) 3JQ7Cc>  
{ xtP:Q9!N  
e.printStackTrace (); EOu[X'gLr  
} ) dk|S\  
} 9!X3Cv|+L  
uOzoE_i
 
//日志 . KLEx]f.  
public static void log(String sMsg) rN|=cn  
{ p=nbsS~":  
System.err.println(sMsg); 5Z_C(5)/Y  
} zTB&Wlt  
u>9` ?O44  
fV>d_6Lf}  
public static void log(int sMsg) oMg-.!6  
{ Gl'G;F$Y-  
System.err.println(sMsg); W
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} ;]grbqXVE  
} 41Q5%2  
$L0sBW&  
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/* q{9 \hEeb  
**TestMethod.java $?W2'Xm!V  
*/ q
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package NetFox; ?lD)J?j  
;&CLb`<y  
g?"QahHG  
public class TestMethod { $k0(iFzR1  
H;\C7w|  
q,)V0Ffe[|  
public TestMethod() K\9CW%W  
{ ///xx/weblogic60b2_win.exe E} XmZxHV  
try{ 0ex.~S_Oj4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); J78.-J5 j0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vwu/33  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *V',@NH#Os  
fileFetch.start(); R&Nl!QTJj  
} H@@ 4n%MK  
catch(Exception e){e.printStackTrace ();} \B~g5}=  
7u&l]NC?y  
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} q&z'S
 
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Ph""[0n%o  
public static void main(String[] args) G!$~'o%/  
{ 3ArHaAv{y  
new TestMethod(); _N|%i J5  
} Ga02Zk  
} ,on]Fts  
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