http断点续传简单实现（java)

/* ?`O Dt]s  
**SiteFileFetch.java D+
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*/ pBu~($%d  
package NetFox; DV~1gr,\  
import java.io.*; 4==LtEp  
import java.net.*; \ow0Y>  
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public class SiteFileFetch extends Thread { KGX?\#-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &^YY>]1Py  
long[] nStartPos; //开始位置 ,/>~J]:\;  
long[] nEndPos; //结束位置 i(c'94M  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 DP_bB(  
long nFileLength; //文件长度 62LQUl]<  
boolean bFirst = true; //是否第一次取文件 *ha9Vq@X  
boolean bStop = false; //停止标志 >KXT2+w  
File tmpFile; //文件下载的临时信息 Fw5r\J87c  
DataOutputStream output; //输出到文件的输出流 K\ \UF  
9?W38EF  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3,B[%!3d  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5+O#5"v_  
{ tgYIM`f  
siteInfoBean = bean; 93(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }a_: oR  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); m,TqyP#  
if(tmpFile.exists ()) t(MlZ>H  
{ 0,;FiOp  
bFirst = false; #Y*AGxk  
read_nPos(); JhDjY8?86  
} :1>R~2  
else 2h6F j&  
{ hTn }AsfLY  
nStartPos = new long[bean.getNSplitter()]; F<w/@.&m  
nEndPos = new long[bean.getNSplitter()]; &,&oTd.  
} i9M6%R1m}E  
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} . yu  
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public void run() WiviH#hF  
{ I>-jKSkwc  
//获得文件长度 tZXtt=M w  
//分割文件 q#Qr@Jf  
//实例FileSplitterFetch _bks*.9}3b  
//启动FileSplitterFetch线程 Gf'V68,l$  
//等待子线程返回 TCF[i
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try{ uj/le0
 
if(bFirst) *qBMt[a  
{ Qzh:*O  
nFileLength = getFileSize(); 95
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if(nFileLength == -1) %r!  
{ >8tE`2[i*  
System.err.println("File Length is not known!"); }RUC#aW1  
} 6]g
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else if(nFileLength == -2) `u-VGd\  
{ D1O7S]j  
System.err.println("File is not access!"); Vq'&t<K#  
} m9xu$z|e  
else >k\*NW  
{ f3l >26  
for(int i=0;i<nStartPos.length;i++) Ruk6+U  
{ SqTm/ t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3nK'yC  
} V`WfJ>{;Z  
for(int i=0;i<nEndPos.length-1;i++) y~S[0]y>  
{ s/To|9D  
nEndPos = nStartPos[i+1]; FJL9
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} Cm;N5i  
nEndPos[nEndPos.length-1] = nFileLength; TPEZ"%=Hg  
} iZyk2kc  
} JrL/LGY  
"iZ-AG!C  
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//启动子线程 ?n@PZL= ]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;LrKXp  
for(int i=0;i<nStartPos.length;i++) kkOYC?zE?  
{ dadMwe_l0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w pCS]2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (x$k\H  
nStartPos,nEndPos,i); 8w*fg6,=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aQ~x$T|  
fileSplitterFetch.start(); Mm[%v t40  
} MA-$aN_(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ga~vQ7I_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Zz3#Kt5t3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", mifYk>J^9  
nEndPos = " + nFileLength); bo -Gh`  
// fileSplitterFetch[nPos.length-1].start(); x)*/3[  
7T2W%JT-,  
"+Qh,fTt  
//等待子线程结束 MK[spV  
//int count = 0; =0]Mc$Ih  
//是否结束while循环 y=j[v},4  
boolean breakWhile = false; bL[PNUG  
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while(!bStop) mmKrmM*1  
{ 25~$qY_  
write_nPos(); sw@2 ?+  
Utility.sleep(500);  7:p]~eM)  
breakWhile = true; c,~44Z  
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for(int i=0;i<nStartPos.length;i++) $cy:G  
{ /pge7P  
if(!fileSplitterFetch.bDownOver) yED^/=\)}  
{ AeJM[fCMa  
breakWhile = false; {oJa8~P  
break; V[bc-m  
} D!sSe|sL^  
} JX/d;N7a  
if(breakWhile) %5KR}NXX6  
break; C1do]1VH  
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//count++; &T|-K\*  
//if(count>4) /&|pXBY$;  
// siteStop(); Yptsq@s  
} :cEe4a  
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%7@H7^s}9  
System.err.println("文件下载结束！"); m{5$4v,[
 
} \9?<E[  
catch(Exception e){e.printStackTrace ();} dB,#`tc=,  
} w:LCm `d  
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//获得文件长度 #~f+F0#%?  
public long getFileSize()
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{ U+RPn?Q  
int nFileLength = -1; H'`(|$:|  
try{ mT>p
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URL url = new URL(siteInfoBean.getSSiteURL()); Zll^tF#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zn x_p/V  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9M=K@a  
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int responseCode=httpConnection.getResponseCode(); (j I|F-i  
if(responseCode>=400) yy74>K  
{ 3d<HIG^W}  
processErrorCode(responseCode); H44&u](8{  
return -2; //-2 represent access is error dtBV0$  
} 3# (5Kco
 
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String sHeader; j)DZmGg&t  
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for(int i=1;;i++) q{ 1U  
{ }\{1`$*~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F)5Aq H/p
 
//Utility.log(in.readLine()); 79x9<,a)  
sHeader=httpConnection.getHeaderFieldKey(i); o5@ jMU;  
if(sHeader!=null) /#=J`*m_  
{ ~b[4'm@  
if(sHeader.equals("Content-Length")) @(?4g-*E  
{ M!l5,ycF  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); D` X6'PP  
break; e;
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} T!A}ipqb  
} v`w?QIB]  
else t>sX.=\$  
break; Lp WEu^j  
} $Ig,cTR.b  
} S:uEK  
catch(IOException e){e.printStackTrace ();} ?KXQ)Y/su  
catch(Exception e){e.printStackTrace ();} x=#5\t9  
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Utility.log(nFileLength); @R&D["!  
|Z^g\l.j{  
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return nFileLength; q$rA-`jw  
} vUs7#*  
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//保存下载信息（文件指针位置） PI \,`^)y  
private void write_nPos() o#) !b:/  
{ L,pSdeq  
try{ <xjv7`G7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); I{I [N &N  
output.writeInt(nStartPos.length); J-<B*ot+lX  
for(int i=0;i<nStartPos.length;i++) B[B<U~I}  
{ kw:D~E(  
// output.writeLong(nPos); j/pQSlV  
output.writeLong(fileSplitterFetch.nStartPos); WGluY>C;  
output.writeLong(fileSplitterFetch.nEndPos); ee^_Dh4  
} MEnHC'nI  
output.close(); JwtI(>cI  
} 73ljW  
catch(IOException e){e.printStackTrace ();} 3F}KrG  
catch(Exception e){e.printStackTrace ();} 5yiiPK$qr  
} E}vO*ZZEw  
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//读取保存的下载信息（文件指针位置） n{r#K_  
private void read_nPos() $ ].k6,%{p  
{ G)B
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try{ 6CmFmc,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U hhmG+  
int nCount = input.readInt(); XWQ0V
  
nStartPos = new long[nCount]; aZ>\*1
 
nEndPos = new long[nCount]; i!oj&&  
for(int i=0;i<nStartPos.length;i++) qg{<&V7fE  
{ u=}bq{  
nStartPos = input.readLong(); QU!'W&F6  
nEndPos = input.readLong(); I*S`I|{J  
} `$SEkYdt  
input.close(); AE4~M`6D  
} x<\D@X^  
catch(IOException e){e.printStackTrace ();} 4 6lEJ  
catch(Exception e){e.printStackTrace ();} ~yH>Ko9F}  
} [Um4\QvUx  
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private void processErrorCode(int nErrorCode) NVqC|uEAF  
{ akW3\(W}  
System.err.println("Error Code : " + nErrorCode); 6Su@a%=j  
} "5JN
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n=
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//停止文件下载 tm1UH 4  
public void siteStop() 6Hbf9,vI  
{ `h9)`*  
bStop = true; V<V\0n!0  
for(int i=0;i<nStartPos.length;i++) _<*GU@  
fileSplitterFetch.splitterStop(); 2C]la  
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} T|s0qQi  
} 71"JL",  
//负责部分文件的抓取 ERRT_G?  
**FileSplitterFetch.java 53t-'K0l  
*/ 8Cs
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package NetFox; %;\G@q_p{  
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import java.io.*; ^_KD&%M6  
import java.net.*; ki~y@@
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public class FileSplitterFetch extends Thread { 90qj6.SQ  
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String sURL; //File URL }S vw,c  
long nStartPos; //File Snippet Start Position T6I%FXm}  
long nEndPos; //File Snippet End Position p=~h|(M|  
int nThreadID; //Thread's ID 3U~lI&  
boolean bDownOver = false; //Downing is over q#(/*AoU  
boolean bStop = false; //Stop identical xe6_RO%  
FileAccessI fileAccessI = null; //File Access interface {y^|ET7  
&6t3SZV  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &oeN#5Es8C  
{ j|&DP-@g/  
this.sURL = sURL; |#&V:GZp  
this.nStartPos = nStart; YXzZ-28,<  
this.nEndPos = nEnd; (}C^_q:7d  
nThreadID = id; $,;S\JmWP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7SK3  
} %[nR|a<  
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public void run() <4Q12:  
{ !b7'>b'J<1  
while(nStartPos < nEndPos && !bStop) k%l_N)38  
{ -jVaS wt  
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try{ Dr6s^}}~n  
URL url = new URL(sURL); g8,?S6\nMz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =a9etF%B  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~#x:z^U  
String sProperty = "bytes="+nStartPos+"-"; NuD[-;N]  
httpConnection.setRequestProperty("RANGE",sProperty); |)-|2cPRur  
Utility.log(sProperty); b4v(k(<  
jJUGZVM6)  
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InputStream input = httpConnection.getInputStream(); GOf`Z'\xt  
//logResponseHead(httpConnection); {Vxc6,=  
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byte[] b = new byte[1024]; ?Q96,T-) c  
int nRead; {Z#e{~m#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >I4p9y(u  
{ |.(CIu~b   
nStartPos += fileAccessI.write(b,0,nRead); 4bi NGl~  
//if(nThreadID == 1) i,#k}CNu  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q]eFd6  
} [0&'cu>  
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Utility.log("Thread " + nThreadID + " is over!"); ym|NT0_0  
bDownOver = true; dI^IK
  
//nPos = fileAccessI.write (b,0,nRead); 6 u-$  
} /mn-+u`K  
catch(Exception e){e.printStackTrace ();} h(@R]GUX  
} }!%JYG^!D  
} ~H^'al2PK  
> -y&$1  
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//打印回应的头信息 vZ$U^>":  
public void logResponseHead(HttpURLConnection con) i<T P:  
{ pWs\.::B  
for(int i=1;;i++) +Qh[sGDdY  
{ ](W5.a,-$L  
String header=con.getHeaderFieldKey(i); D XV@DQ  
if(header!=null) 7}4'dW.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <nWKR,  
Utility.log(header+" : "+con.getHeaderField(header)); , 3X: )  
else TN35CaSmq  
break; F{k$Atb?g/  
} BXg!zW%+  
} >
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public void splitterStop() 7qe7Fl3  
{ *@_u4T7|{  
bStop = true; keLR1qf  
}
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} :O $@shV  
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/* I-b_h5ZD6  
**FileAccess.java d2rL 8jW  
*//文件访问(定位，写) \q~w<%9Dq  
package NetFox; D ]OD.  
import java.io.*; HA6G)x  
.
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public class FileAccessI implements Serializable{ EgTFwEj  
 ep+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (1CJw:  
RandomAccessFile oSavedFile; ?Z q_9T7  
long nPos; 4% HGMr  
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public FileAccessI() throws IOException 'p%=<0vrr  
{ ZJ;LD*  
this("",0); *'D=1{WZ!  
} z[fB!O  
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public FileAccessI(String sName,long nPos) throws IOException zZ%DtxUoU.  
{ }A]BpSEP  
oSavedFile = new RandomAccessFile(sName,"rw"); ,c>N}*6h=W  
this.nPos = nPos; ^q ;Cx7T_p  
oSavedFile.seek(nPos); FigR1/3o'6  
} ^[k0k(_  
3{"byfO#%  
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public synchronized int write(byte[] b,int nStart,int nLen) NbtGlSs8  
{ AoBoFZLl3  
int n = -1; 9
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try{ z3a-+NjDm  
oSavedFile.write(b,nStart,nLen); }e 9!xA  
n = nLen; ;54(+5pqx  
} 5[C~wvO  
catch(IOException e) n`q2s'Pc  
{ @mf({Q>  
e.printStackTrace (); g\U/&.}DN  
} 79ckLd9  
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return n; o(*F])d
;  
} "O*x' XhN  
|; $Bb866/  
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} 9Bz0MUbrLl  
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/* xjo;kx\y^  
**SiteInfoBean.java )6{< i5nJ\  
*/ Nt]qVwUm'Y  
package NetFox; #;[Bl=3(  
@%1IkvJV  
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public class SiteInfoBean { ;+ azeW^  
0VN7/=n|  
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private String sSiteURL; //Site's URL @x1%)1  
private String sFilePath; //Saved File's Path !Xj#@e  
private String sFileName; //Saved File's Name qI%&ay"/  
private int nSplitter; //Count of Splited Downloading File V1B(|P  
u-JpI-8h  
#)s!}X^  
public SiteInfoBean() Fj1NN  
{//nSplitter的缺省值为5  ?CP2AK  
//default value of nSplitter is 5 |;+qld[4z  
this("","","",5); a?F!,=F  
} lCJ6Ur;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) b9~A-Z  
{ y6-XHeU  
sSiteURL= sURL; Q&CEl
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sFilePath = sPath; `'i( U7?  
sFileName = sName; a 7#J2r  
this.nSplitter = nSpiltter; }#1/fok  
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%{!R l@  
} C&+6>L@  
Fv8f+)k)Z~  
/7D<'MF  
public String getSSiteURL() }4&/VvN  
{ P(,?#+]-  
return sSiteURL; w##^}nHOR  
} Qd]we$G  
A#rh@8h+  
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public void setSSiteURL(String value) ?A?F.n`  
{ =Mj0:rW  
sSiteURL = value; =dZHYO^
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} D3D}DaEYj  
uo2'"@[e  
! zL1;d  
public String getSFilePath() tF7hFL5f  
{ tGjhHp8}c  
return sFilePath; NBYH;h P  
} x|i_P|Z  
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public void setSFilePath(String value) d$t40+v  
{ DY\J[l<<  
sFilePath = value; (UL4+ta  
} t~``md4  
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public String getSFileName() !4(zp;WY^  
{ o]ePP,  
return sFileName; oDn|2Sdqd  
} TP%+.#Fu  
.fAv*pUzU  
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public void setSFileName(String value) o`n$b(VZ  
{ EON:B>2a  
sFileName = value; `d\r;cE%lm  
} W$0^(FH[  
-0Cnp/Yj@  
~q+hV+fa>  
public int getNSplitter() +s++7<C  
{
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return nSplitter; ea'&xs#GK  
} H[ m<RaG8  
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58 bCUh#uw  
public void setNSplitter(int nCount) 3djC;*,9,  
{ pav'1d%  
nSplitter = nCount; mN|r)4{`  
} x/!5K|c  
} -VxDNT}Tr  
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/* wE]K~y!`  
**Utility.java q1?&Ev^  
*/ s{0aBeq  
package NetFox; H+E$:)gN  
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public class Utility { <-'$~G j  

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public Utility() #Tw@wfaq)  
{ c;?fMX  
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} N@ \&1I`c$  
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//线程睡眠 #>lG7Ns|4  
public static void sleep(int nSecond) #J (~_%Wi  
{ JN+_|`  
try{ jhu07HX_  
Thread.sleep(nSecond); kQ1w5mCh  
} ^9Qy/Er'  
catch(Exception e) =X\^J  
{ >/[GTqi  
e.printStackTrace (); ApBWuXp|u  
} F8-?dpf'  
} R^?/' dr  
2c6g>?  
//日志 #Cpd9|  
public static void log(String sMsg) @+3kb.P%7  
{ wLc4Dm*V  
System.err.println(sMsg); 1 zw*/dp  
} Ym%xx!9  
wE+${B03  
.*m>\>Gsgw  
public static void log(int sMsg) 7d LuX   
{ ;AO#xv+#  
System.err.println(sMsg); !?c|XdjZ  
} q9Y9w(  
} ^nbnbU4'  
iQDx{m3]  
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/* Z}$TKO*u  
**TestMethod.java )W/;=K  
*/ cufH?Xg<  
package NetFox; ck?YI]q|  
dXF^(y]l  
p w8 s8?  
public class TestMethod { ,) J~,^f6  
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lXcx@
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public TestMethod() 3EJt%}V$k  
{ ///xx/weblogic60b2_win.exe :VTTh |E%#  
try{ ULMu19>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); If\fLhM  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6DH~dL_",%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "g$IP9?U  
fileFetch.start(); /p8dZ
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} DI+fwXe
g  
catch(Exception e){e.printStackTrace ();} qkiI/nH3  
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` ,SiA-3*  
} t+9][Adf  
v`M3eh@$A  
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public static void main(String[] args) d_IAs  
{ &mb{.=  
new TestMethod(); Y "/]|'p  
} ~ 4kc/a  
} "'D=,*  
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