http断点续传简单实现（java)

/* ::kpl2r\c  
**SiteFileFetch.java pq%t@j(X  
*/ y-D>xV
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package NetFox; L; @aE[#z  
import java.io.*; F%w\D9+P  
import java.net.*; E `?S!*jm  
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public class SiteFileFetch extends Thread { <m-Ni  
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SiteInfoBean siteInfoBean = null; //文件信息Bean kO /~i  
long[] nStartPos; //开始位置 H0 {Mlu9  
long[] nEndPos; //结束位置 aY3pvOV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 s{b0#[  
long nFileLength; //文件长度 `[w}hFl~q  
boolean bFirst = true; //是否第一次取文件 2l]C55p)s  
boolean bStop = false; //停止标志 $%lHj+(  
File tmpFile; //文件下载的临时信息 g{rt^B  
DataOutputStream output; //输出到文件的输出流 I8XGU)  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @G^j8Nl+J}  
public SiteFileFetch(SiteInfoBean bean) throws IOException H@VBP Q}Q  
{ Y j,9V],  
siteInfoBean = bean; 1c1e+H  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); EU`' 8*4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >b[4  
if(tmpFile.exists ()) !pE>O-| K  
{ $`cy'ZaF  
bFirst = false; Yb,G^+;  
read_nPos(); W\d0  
} ^XjvJa  
else j@kRv@  
{ ;,[EJR^CI  
nStartPos = new long[bean.getNSplitter()]; 1q;I7_{ 2
 
nEndPos = new long[bean.getNSplitter()]; ua6*zop  
} PW(_yB;  
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} BxW||O|_N"  
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public void run() LIm$Wl1U  
{ S^_JC  
//获得文件长度 LNsE7t  
//分割文件 D/NIn=>
j  
//实例FileSplitterFetch ur,V>J<5A  
//启动FileSplitterFetch线程 gK]T
}  
//等待子线程返回 'Q^G6'(SaK  
try{ 4AG&z,[  
if(bFirst) [qc6Q:  
{ \!? P
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nFileLength = getFileSize(); dUBVp 9PB  
if(nFileLength == -1) z.Ve#~\  
{ q[We][Nrzb  
System.err.println("File Length is not known!"); VH$\ a~|  
} `UzCq06rJ1  
else if(nFileLength == -2) F~11 _  
{ TLR Lng  
System.err.println("File is not access!"); ul]m>W  
} kC,DW%Ls  
else 1{Sx V  
{ G5X|JTzpu<  
for(int i=0;i<nStartPos.length;i++) g/J^K*3]  
{ }J4BxBuV8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |iF1A  
} 7ZR0M&pX  
for(int i=0;i<nEndPos.length-1;i++) l.Lc]ZpB  
{ {#d
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nEndPos = nStartPos[i+1]; p]J]<QaZD  
} Cys/1DkE  
nEndPos[nEndPos.length-1] = nFileLength; sIQMUC[!
 
} 0Zp<=\!;  
} 0(.R?1*:Rf  
.5$V7t.t$\  
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//启动子线程 /Wta$!X{-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P89Dg/P  
for(int i=0;i<nStartPos.length;i++) :W1tIB  
{ f{oxF?|89  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _^,[
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nStartPos,nEndPos,i); LXOF
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +eVpMD( l  
fileSplitterFetch.start(); 3mnLV*aRt  
} J>&dWKM3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~>wq;T:=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +O%a:d%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'j=PbA  
nEndPos = " + nFileLength); 4'u|L&ow  
// fileSplitterFetch[nPos.length-1].start(); 0v,`P4_k  
YH:W]  
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//等待子线程结束 !{|yAt9kP  
//int count = 0; U7Sl@-#|  
//是否结束while循环 %.r5E2'  
boolean breakWhile = false; itvy[b-*  
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M KE[Yb?  
while(!bStop) <=LsloI  
{ s
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write_nPos(); ,YuWz$aF{  
Utility.sleep(500); +k"8e?/e.  
breakWhile = true; {Rh+]=7  
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for(int i=0;i<nStartPos.length;i++) okW)s*7  
{ ~wQ WWRk  
if(!fileSplitterFetch.bDownOver) bB[*\  
{ }j5@\c48  
breakWhile = false; I(r5\A=  
break; S4AB tKG  
} ZYp-dlEXq  
} hgMnO J  
if(breakWhile) .<|4PG  
break; GCmVmOdKr  
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//count++; >0G}, S  
//if(count>4) K,T]Fuy  
// siteStop(); ]k%KTvX*G  
} pJ@DHj2@  
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System.err.println("文件下载结束！"); ?VHwYD.B  
} >w2WyYJYH  
catch(Exception e){e.printStackTrace ();} MjeI?k}LJ  
} 0GLB3I >  
b`%e{99\  
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//获得文件长度 jjlCi<9CQ^  
public long getFileSize() ;`Ch2b1+  
{ *d*;M>  
int nFileLength = -1; 7m)ykq:?  
try{ _|V+["IS  
URL url = new URL(siteInfoBean.getSSiteURL()); V,%5 hl'&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <EE+ S#z  
httpConnection.setRequestProperty("User-Agent","NetFox");
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int responseCode=httpConnection.getResponseCode(); rcb/X`l=  
if(responseCode>=400) }u$aPS<$!  
{ /3HWP`<x  
processErrorCode(responseCode); _1bd)L&dF  
return -2; //-2 represent access is error
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} C=f(NpyD6  
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String sHeader; rnrx%
Q  
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for(int i=1;;i++) kj"_Y"q=  
{ vnOF$6n  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [==Z1Q;=  
//Utility.log(in.readLine()); ]3cf}Au  
sHeader=httpConnection.getHeaderFieldKey(i); SCC/ <o  
if(sHeader!=null) $ }bC$?^  
{ *j;r|P;g  
if(sHeader.equals("Content-Length")) YuW\GSV00  
{ g?Ty5~:lq  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); YQd&rkr  
break; xaaxj  
} 5nw9zW :'  
} 17i@GnbNb  
else .j@n6RyN  
break; "f$A0RL  
} OnPLz"-  
} ue2nfp  
catch(IOException e){e.printStackTrace ();} hA19:H=7R0  
catch(Exception e){e.printStackTrace ();} m!>'}z  
v=^)`C6Ma  
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Utility.log(nFileLength); X-^Oz@.>  
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return nFileLength; 5rSth.&  
} 0-O.*Q^  
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9W r(w  
//保存下载信息（文件指针位置） n;Wf|>  
private void write_nPos() { J%$.D(/  
{ f3&//h8  
try{ +f~3FXM  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^]K)V  
output.writeInt(nStartPos.length); zL{@LHP  
for(int i=0;i<nStartPos.length;i++) @"5u~o')@v  
{ ^IZ0M1&W;  
// output.writeLong(nPos); s8O+&^(U  
output.writeLong(fileSplitterFetch.nStartPos); WkmS   
output.writeLong(fileSplitterFetch.nEndPos); ,;& PKY  
} 90I3_[Ii  
output.close(); yUlQPrNX  
} t`D@bzLC%  
catch(IOException e){e.printStackTrace ();} f}uCiV!?v  
catch(Exception e){e.printStackTrace ();} "qp_*Y  
} tHo/uW_~I  
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//读取保存的下载信息（文件指针位置） d$ 7b  
private void read_nPos() )y Y;%
 
{ bhT]zsBK  
try{ 2UJ0%k  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {u][q &n  
int nCount = input.readInt(); id9T[^h  
nStartPos = new long[nCount]; +u.L6GcB  
nEndPos = new long[nCount]; f%l#g]]  
for(int i=0;i<nStartPos.length;i++) tq
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{ >U.u
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nStartPos = input.readLong(); 8#AXK{  
nEndPos = input.readLong(); PUo&>  
} c9={~  
input.close(); Q&;qFv5-l  
} Q:=/d$*xd  
catch(IOException e){e.printStackTrace ();} ~+ur*3X  
catch(Exception e){e.printStackTrace ();} /PS]AM  
} sP8B?Tn1W  
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private void processErrorCode(int nErrorCode) r4zS,J;,  
{ GT0'bge  
System.err.println("Error Code : " + nErrorCode); 351'l7F\  
} ?Fw/c0  
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//停止文件下载 .;s4T?j@w  
public void siteStop() ak&v/%N  
{ ShxX[k  
bStop = true; 5eJd$}Lbc  
for(int i=0;i<nStartPos.length;i++) EeJ]> 1  
fileSplitterFetch.splitterStop(); lvffQ_t  
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} BW[K/l~"$:  
} K.Ir+SB  
//负责部分文件的抓取 &Gl&m@-j  
**FileSplitterFetch.java _Fg
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*/ !ZdUW]  
package NetFox; p:))ne:7  
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import java.io.*; $T0[  
import java.net.*; 0:p#%Nvg  
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} U.B$4Q  
public class FileSplitterFetch extends Thread { L1BpY-=  
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String sURL; //File URL X'<xw  
long nStartPos; //File Snippet Start Position ;C%EF  
long nEndPos; //File Snippet End Position 1C{n\_hR  
int nThreadID; //Thread's ID b*i+uV?  
boolean bDownOver = false; //Downing is over &kBs'P8>  
boolean bStop = false; //Stop identical a4YyELXe  
FileAccessI fileAccessI = null; //File Access interface ^(3k uF  
p,/^x~m3a  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException yuBBO:\.  
{ +V^_
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this.sURL = sURL; 6iC:l%|u  
this.nStartPos = nStart; RCr:2 Iz  
this.nEndPos = nEnd; i:72FVo  
nThreadID = id; wr(?L7 $+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |Rc#Q<Vh|  
} n66_#X  
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public void run() ' r/1+.  
{ o6oYJ`PY  
while(nStartPos < nEndPos && !bStop) NGu]|p  
{ mLSAi2Y  
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try{ |)?T([  
URL url = new URL(sURL); U$}]zaB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w.\:I[  
httpConnection.setRequestProperty("User-Agent","NetFox"); l(W3|W#P  
String sProperty = "bytes="+nStartPos+"-"; G 2##M8:U0  
httpConnection.setRequestProperty("RANGE",sProperty); P<~y$B  
Utility.log(sProperty); ikC;N5Sw  
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InputStream input = httpConnection.getInputStream(); 5o*x?P!$  
//logResponseHead(httpConnection); S6 *dp68  
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byte[] b = new byte[1024]; YuZnuI@m9  
int nRead; ]M/w];:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :%gBcL9T  
{ QG.FW;/L,  
nStartPos += fileAccessI.write(b,0,nRead); HO>uS>+  
//if(nThreadID == 1) 9viC3bj.o  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "rtmDNpL  
} 3h&s=e!  
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Utility.log("Thread " + nThreadID + " is over!"); 42M3c&@P  
bDownOver = true; (iFhn*/ E  
//nPos = fileAccessI.write (b,0,nRead); pH%K4bV)8  
} "F&uk~ b$  
catch(Exception e){e.printStackTrace ();} F`l1I=;  
} Nf1l{N  
} VQyDd~Za  
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//打印回应的头信息 e=U7w7(s9
 
public void logResponseHead(HttpURLConnection con) Yi:+,-Fso  
{ qXW5_iX  
for(int i=1;;i++) P;GUGG*W  
{ yI!K quMC  
String header=con.getHeaderFieldKey(i); fXN;N&I  
if(header!=null) Xs`/q}R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); dFlx6H+R!0  
Utility.log(header+" : "+con.getHeaderField(header)); YeQX13C"Z  
else &AzA0r&,  
break; t0Uax-E(  
} Q["}U7j  
} 4D8q
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{,m!%FDL  
public void splitterStop() L_(|5#IDw  
{ J<2N~$  
bStop = true; ]du pU"VV  
} "-9YvB#  
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} <H.Ml>q:r  
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/* d%<Uh(+:  
**FileAccess.java W\"cp[b  
*//文件访问(定位，写) <B)lV'!Bd  
package NetFox; QS[%`-dR2  
import java.io.*; *N't ;  
\(Iy>L.  
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public class FileAccessI implements Serializable{ Gc>\L3u  
u+*CpKR}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o_cj-  
RandomAccessFile oSavedFile; qVf~\H@  
long nPos; B!:(*lF  
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public FileAccessI() throws IOException B|8(}Ciqx  
{ wi!Ml4Sb  
this("",0); pl%ag~i5  
} >o@WT kF]  
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8u>E(Vmpu  
public FileAccessI(String sName,long nPos) throws IOException nD!^0?  
{ ZEB1()GB  
oSavedFile = new RandomAccessFile(sName,"rw"); IgVxWh#  
this.nPos = nPos; PffRV7qU0  
oSavedFile.seek(nPos);  @>B
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} ^T^fowt=r  
M$w^g8F27H  
I)6)~[:'  
public synchronized int write(byte[] b,int nStart,int nLen) %f@]-  
{ C@K@TfK!M  
int n = -1; ,+2ytN*  
try{ lGxG$0`;;  
oSavedFile.write(b,nStart,nLen); 46*?hA7@r(  
n = nLen; "kMpa]<c-6  
} bH&[O`vf  
catch(IOException e) IE
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{ doG&qXw  
e.printStackTrace (); )yjHABGJ  
} &AW?!rH  
`
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return n; L./
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} &cZ
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} 7[Y<5T]  
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/* ^Xh9:OBF  
**SiteInfoBean.java 
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*/ srUpG&Bcx  
package NetFox; K{N#^L!  
mI}'8.  
@L`t/OD  
public class SiteInfoBean { .Emw;+>  
)5hS;u&b  
@}#$<6|  
private String sSiteURL; //Site's URL m|'TPy  
private String sFilePath; //Saved File's Path D9JT)a  
private String sFileName; //Saved File's Name ++xEMP)  
private int nSplitter; //Count of Splited Downloading File 9^`G `D
 
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*K!V$8k=99  
public SiteInfoBean() Q&yfl  
{//nSplitter的缺省值为5 QGfU:  
//default value of nSplitter is 5 'H+pwp"M@  
this("","","",5); 8He^j5  
} _uL m!ku  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7)~/`w)P  
{ /z6NJ2jb  
sSiteURL= sURL; ]e R1 +Nl  
sFilePath = sPath; |FH/Q-7[  
sFileName = sName; an.)2*u  
this.nSplitter = nSpiltter; [&6l=a  
y2&G0y  
Q9{%  
} }56"4/ Z  
f:e~ystm  
!qT.D:!@zF  
public String getSSiteURL() H+F'K XP*K  
{ haS`V  
return sSiteURL; s(F^P  
} a(!:a+9WOP  
&%rXRP  
amOBUD5Ld`  
public void setSSiteURL(String value) SI U"cO4  
{ s>^*GQw  
sSiteURL = value; (Zx;GS  
} zkB_$=sbn#  
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8z\WyDz  
public String getSFilePath() cvi+AZ=  
{ C^]bXIb  
return sFilePath; Bx;bc  
} I 91`~0L*  
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public void setSFilePath(String value) BHqJ~2&FDW  
{ EPW Iu)A  
sFilePath = value; b>?X8)f2e  
} 
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+ ,0RrD )  
G ?H`9*y  
public String getSFileName() OP{ d(~+  
{ -&y{8<bu4H  
return sFileName; Xfk&{zO-j  
} gtJUQu p2  
&H`yDrg6U  
4, 8gf2  
public void setSFileName(String value) mbU[fHyV  
{ &$|k<{j[<f  
sFileName = value; Cj,fP[p#7  
} O]90F  
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public int getNSplitter() BB>3Kj:|  
{ j'I$F1>Te  
return nSplitter; K'7i$bl%  
} {C[<7ruF  
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public void setNSplitter(int nCount) #P<v[O/rA  
{ JEGcZeq)  
nSplitter = nCount; 26&^n Uy  
} AS'a'x>8>,  
} 79z(n[^  
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52,pCyU  
/* wqK>=Ri_  
**Utility.java hT#[[md"  
*/ `fj(xrI  
package NetFox; iO(9#rV  
8S&`  
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public class Utility { FD,M.kbg  
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public Utility() \|L@  
{ \2*<Pq  
)W(?wv!,  
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}  3_+-t5  
1.]#FJe  
//线程睡眠 g< M\zD  
public static void sleep(int nSecond) bo4 :|Z  
{ ubjuuha"  
try{ IF(W[J  
Thread.sleep(nSecond); 3 8m5&5)1F  
} GTyS8`5E*  
catch(Exception e) %F` cNw]  
{ 5M;fh)fT  
e.printStackTrace (); &>ii2% 4  
} g>CF|Wj  
} r=~yUT  
|)B&-~a+p  
//日志 =hH>]$J[  
public static void log(String sMsg) )
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{ lc,{0$ 1<  
System.err.println(sMsg); tz4MT_f  
} <=l!~~%  
{Nuwz|Ci  
&HNJ'  
public static void log(int sMsg) G^ZL,{  
{ TxoMCN?7c  
System.err.println(sMsg); 7<<pP  
} $6Lgaz  
} Ia=wf"JS)  
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),(ejRP'r  
/* eu@-v"=w  
**TestMethod.java RY8;bUSR  
*/ Cg?D<l4  
package NetFox; <UQaRI[55  
3;zJ\a.+  
M}k )Ep9  
public class TestMethod { Ek~Qp9B  
7hZCh,O  
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public TestMethod() B$1e AwT9  
{ ///xx/weblogic60b2_win.exe /pan{.< k  
try{ s#/JMvQ#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); gbL99MZ@~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); iNUisl  
SiteFileFetch fileFetch = new SiteFileFetch(bean); QZ$94XLI  
fileFetch.start(); 9$c0<~B\  
} ({zt=}r,  
catch(Exception e){e.printStackTrace ();} p+SFeUp  
=;-/( C  
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} [cwc}f^  
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XaW@CW  
public static void main(String[] args) LzB)o\a  
{ >*(4evU  
new TestMethod(); $~`a,[e<  
} .^>[@w3  
} A)Wp W M  
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