http断点续传简单实现（java)

/*
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**SiteFileFetch.java |7WzTz  
*/ 6 .DJRY  
package NetFox; 2^Gl;3  
import java.io.*; ;@K,>$ur-  
import java.net.*; G[u_Uu=>  
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public class SiteFileFetch extends Thread { AG)N^yd  
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SiteInfoBean siteInfoBean = null; //文件信息Bean >K#Z]k  
long[] nStartPos; //开始位置 FVLXq0<Cj  
long[] nEndPos; //结束位置 77/y{#Sk  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4@#1G*OO  
long nFileLength; //文件长度 k1>%wR  
boolean bFirst = true; //是否第一次取文件 {npKdX  
boolean bStop = false; //停止标志 aA%$<ItH  
File tmpFile; //文件下载的临时信息 >rlQY>5pH  
DataOutputStream output; //输出到文件的输出流 "%ag^v9  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^8)&~q*  
public SiteFileFetch(SiteInfoBean bean) throws IOException U0u@[9!  
{ D+rDgrv  
siteInfoBean = bean; GSV,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #Q6wv/"Ub  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S6}_Z  
if(tmpFile.exists ()) S}e*~^1J  
{ &nn!{S^  
bFirst = false; _5M!ec  
read_nPos(); )?'sw5C  
} ,)V*xpp  
else +`f gn9p  
{ .}ZX~k&P  
nStartPos = new long[bean.getNSplitter()]; *Q=-7am  
nEndPos = new long[bean.getNSplitter()]; F']Vg31c  
} 6 6x} |7  
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} O|,+@qtH  
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public void run() =Cs$0aA  
{ pvy;L[c  
//获得文件长度 PGT!HdX#{  
//分割文件 : ` F>B  
//实例FileSplitterFetch eHv~?b5l  
//启动FileSplitterFetch线程 KGi@H
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//等待子线程返回 DWJ%r"aN  
try{ $qQ6u!  
if(bFirst) V2w[0^L  
{ {z@vSQ=)=P  
nFileLength = getFileSize(); G+[>or
}  
if(nFileLength == -1) R ;5w*e}?5  
{ iBJ*6or
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System.err.println("File Length is not known!"); *sJx0<!M}  
} F&lc8  
else if(nFileLength == -2) ScGmft3A  
{ 9Lz)SYd  
System.err.println("File is not access!"); qCgP8U/jv  
} a}E8ADyC  
else HT?`PG  
{ ?RWd"JTGue  
for(int i=0;i<nStartPos.length;i++) uNXh"?  
{ `k\]I |6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b,T=0W  
} Zpb3>0<R  
for(int i=0;i<nEndPos.length-1;i++) m)_1->K  
{ /UyW&]nK  
nEndPos = nStartPos[i+1]; [%l+ C~m  
} 58e{WC  
nEndPos[nEndPos.length-1] = nFileLength; Zy*}C,Z  
} 3{MIBMA  
} w#PaN83+  
WS(@KN  
m OmT]X  
//启动子线程
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 'Iyk`=R  
for(int i=0;i<nStartPos.length;i++) .v1rrH?  
{ rLL;NTN+/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]v_xEH}T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), MW*}+ PC
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nStartPos,nEndPos,i); iXl1S[.l  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DA@ { d-A  
fileSplitterFetch.start(); [&3"kb  
} NlcWnSv  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,7%(Jj$ ^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;o^m"I\y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G#@<bg3  
nEndPos = " + nFileLength); ;k/0N~  
// fileSplitterFetch[nPos.length-1].start(); P\zi:]h[Gh  
n+uq|sYVa  
)1x333.[c  
//等待子线程结束 0l 3RwWj  
//int count = 0; 4QIvxH  
//是否结束while循环 $ @1&G~x  
boolean breakWhile = false; `SW`d<+L  
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82/iVm1  
while(!bStop) K=(&iq!VO  
{ ;4qalxzu  
write_nPos(); ae!_u \$  
Utility.sleep(500); fs)O7x-B(  
breakWhile = true; r1?LKoJOn  
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for(int i=0;i<nStartPos.length;i++) wk
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{ ^E:;8h4$9  
if(!fileSplitterFetch.bDownOver) .!6ufaf$  
{ T3?kabbF  
breakWhile = false; ;QEGr|(  
break; -5>g 0o2  
} T@vVff  
} uo%O\}#u9  
if(breakWhile) \pPq]k  
break; T2(+
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KPO((G0&  
//count++; lJYv2EZ  
//if(count>4) \uPT-M*  
// siteStop(); 6|jE3rHw  
} 3t_5Xacj  
&Y#9~
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System.err.println("文件下载结束！"); 6)bfd^JYn  
} s[s^z<4G  
catch(Exception e){e.printStackTrace ();} 9n%W-R.  
} ljf9L:L  
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//获得文件长度 1Gqtd^*;  
public long getFileSize() dl;A'/(t  
{ |ITg-t  
int nFileLength = -1; UNAuF8>K  
try{ ?t
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URL url = new URL(siteInfoBean.getSSiteURL()); ^|\?vA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &WRoNc  
httpConnection.setRequestProperty("User-Agent","NetFox"); .-34g5  
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int responseCode=httpConnection.getResponseCode(); d z\b]H]  
if(responseCode>=400) Wex4>J<`/
 
{ ypifXO;m7  
processErrorCode(responseCode); iH$N HfH  
return -2; //-2 represent access is error Uis P 8/k  
} dJ;;l7":~  
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String sHeader; V('b|gsEo  
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for(int i=1;;i++) #,9|Hr%  
{ bQ4 }no0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); a
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//Utility.log(in.readLine()); o._^  
sHeader=httpConnection.getHeaderFieldKey(i); So 5{E4[  
if(sHeader!=null) c~C W-%wN  
{ i'u;"ot=  
if(sHeader.equals("Content-Length")) 7xcYM  
{ qqAsh]Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !3&}r  
break; h}d7M55#|  
} G?g7G,|d  
} Z:OO|x  
else KWYG\#S0]  
break; ^49moC-  
} g[n8N
{s  
} Lr~K3nb  
catch(IOException e){e.printStackTrace ();} ?t"PawBWE  
catch(Exception e){e.printStackTrace ();} 3HiW1*5W  
lt]U?VZ   
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Utility.log(nFileLength); t2gjhn^p  
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return nFileLength; 2u:
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} Ue7W&N^E  
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//保存下载信息（文件指针位置） g:)vthOs  
private void write_nPos() +Oscy-;  
{ 1W8W/Y=hT  
try{ O^:h_L  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2=|IOkY  
output.writeInt(nStartPos.length); =V , _  
for(int i=0;i<nStartPos.length;i++) [4t KJ+v  
{ Y>%NuL|s  
// output.writeLong(nPos); K|/a]I":  
output.writeLong(fileSplitterFetch.nStartPos); SrtmpQ  
output.writeLong(fileSplitterFetch.nEndPos); izw}25SW  
} aVb]H0  
output.close(); ?x0yiV~dL  
} 2uTa}{/%  
catch(IOException e){e.printStackTrace ();} ww2Qa-K  
catch(Exception e){e.printStackTrace ();} bi[l,  
} +g[B &A!d+  
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//读取保存的下载信息（文件指针位置） .R'i=D`Pz  
private void read_nPos() i=D,T[|>a  
{ ^&.?kJM  
try{ LA+MX0*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); v3"xJN_,[p  
int nCount = input.readInt(); $Da^z[8e  
nStartPos = new long[nCount]; ?X1#b2s  
nEndPos = new long[nCount]; iQF}x&a<  
for(int i=0;i<nStartPos.length;i++) ~}AP@t*  
{ {;E/l(HNI  
nStartPos = input.readLong(); (?!0__NN;  
nEndPos = input.readLong(); E-D5iiF  
} ss<'g@R  
input.close(); abnd U,s  
} #77UKYj2L-  
catch(IOException e){e.printStackTrace ();} U VKN#"_{  
catch(Exception e){e.printStackTrace ();} ^4[[+r  
} %np#Bv-L  
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private void processErrorCode(int nErrorCode)
"BRE0Ir:  
{ ,LZ:y1z'V-  
System.err.println("Error Code : " + nErrorCode); Anv8)J!9u  
} uH[0kh  
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N 3c*S"1  
//停止文件下载 E'8Bw7Tz  
public void siteStop() 5m42Bqy"  
{ p'qH [<s  
bStop = true;  G{.+D2  
for(int i=0;i<nStartPos.length;i++) HH?*"cKF~  
fileSplitterFetch.splitterStop(); r<v%Zp  
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} njMy&$6a##  
} ~P_kr'o  
//负责部分文件的抓取 ]Qr8wa>Z  
**FileSplitterFetch.java #pSOZX  
*/ oDUMoX%4s  
package NetFox; \T9UbkR  
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import java.io.*; |sa7Y_  
import java.net.*; @3c#\jx  
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public class FileSplitterFetch extends Thread { 7V (7JV<>  
=bWq 3aP)P  
}!V<"d,!  
String sURL; //File URL )c/y07er  
long nStartPos; //File Snippet Start Position )`mF.87b&h  
long nEndPos; //File Snippet End Position dY<#a,eS  
int nThreadID; //Thread's ID ; ZV^e  
boolean bDownOver = false; //Downing is over 5R`6zhf  
boolean bStop = false; //Stop identical `YNC_r#tG  
FileAccessI fileAccessI = null; //File Access interface %E"/]!}3  
"NH+qQhs  
7RE6y(V1  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B:4qW[U#  
{ ~^~RltY  
this.sURL = sURL; tq[",&K  
this.nStartPos = nStart; ~@b}=+n  
this.nEndPos = nEnd; \C#b@xLnX  
nThreadID = id; 5,BkwAr+6[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Y&f[2+?2NK  
} 3b@1Zahz  
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public void run() K)UOx#xe1  
{ "!6~*!]c  
while(nStartPos < nEndPos && !bStop) 8M+F!1-#  
{ xKST-:c+  
P=[x!}.I  
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try{ o!r4 frP  
URL url = new URL(sURL); BON""yIC   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !9LAXM  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y~hd<8 ~  
String sProperty = "bytes="+nStartPos+"-"; -^Km}9g  
httpConnection.setRequestProperty("RANGE",sProperty); `AHNk7 t=  
Utility.log(sProperty); 5zw23!  
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InputStream input = httpConnection.getInputStream(); rbun5&RCyW  
//logResponseHead(httpConnection); gc7:Rb^E5t  
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byte[] b = new byte[1024]; u$,Wyi )L  
int nRead; rI66frbj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) , gr&s+  
{ GVc[p\h(  
nStartPos += fileAccessI.write(b,0,nRead); /\uH[[s  
//if(nThreadID == 1) .Xz"NyW  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #u5;utY:F  
} S%s|P=u  
"jJdUFN  
]AA*f_!  
Utility.log("Thread " + nThreadID + " is over!"); r]EZ)qp^@  
bDownOver = true; X:-bAu}D  
//nPos = fileAccessI.write (b,0,nRead); PSqtZN  
} ~uZLe\>K  
catch(Exception e){e.printStackTrace ();} VfC[U)w*vm  
} .y_bV=  
} \3(|c#c  
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//打印回应的头信息 .'{6u;8  
public void logResponseHead(HttpURLConnection con) ID).*@(I"  
{ _KhEwd  
for(int i=1;;i++) ]#-/i2-K  
{ i2}=/  
String header=con.getHeaderFieldKey(i); 5A]
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if(header!=null) `MYKXBM  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `Y({#U  
Utility.log(header+" : "+con.getHeaderField(header)); 9c5G6n0  
else ah"MzU)  
break; 9q)nNX<$)  
} L5qCv -{  
} I;.! hV>E  
;/^]|  
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public void splitterStop() y7IbE  
{ (zro7gKked  
bStop = true; ?r'TH/>  
} (VXx G/E3  
];{
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} L!b0y7yR  
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/* "K$Wh1<7  
**FileAccess.java %f> |fs  
*//文件访问(定位，写) [cLU
*:  
package NetFox; IU'!?XVo  
import java.io.*; N" Jtg@w  
MHr0CYyb.  
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public class FileAccessI implements Serializable{ Vq)gpR  
Yx}"> ;\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ?(NT!es  
RandomAccessFile oSavedFile; 5IE+
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long nPos; uM#U!  
;]oXEq`  

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public FileAccessI() throws IOException HSr"M.k5  
{ kSDa\l!W]  
this("",0); hKzBq*cV  
} ug6f   
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public FileAccessI(String sName,long nPos) throws IOException w{zJE]7  
{ \`Ph=lJO  
oSavedFile = new RandomAccessFile(sName,"rw"); 6aF'^6+a  
this.nPos = nPos; qvfAG
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oSavedFile.seek(nPos); ekl?K~  
} ({H+ y 9n  
^~r&}l4c,  
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public synchronized int write(byte[] b,int nStart,int nLen) <GT>s  
{ [,o5QH\Etq  
int n = -1; v1X&p\[d  
try{ r@ T-Hi  
oSavedFile.write(b,nStart,nLen); &W)+8N,L  
n = nLen; [;IDTo!<>  
} X\3
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catch(IOException e) |!xfIR>=F  
{ [`zbf_RyO  
e.printStackTrace (); !AD0-fZ  
} {7Gx9(  
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d[>N6?JA/  
return n; +zVcOS*-  
} pT ocqJ22  
;(Ajf.i  
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} @^:7UI_  
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/* ~g K-5}%!  
**SiteInfoBean.java XEUa  
*/ z"s%#/#  
package NetFox; 7S dV%"  
vzohq1r5  
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public class SiteInfoBean { =_?pOq  
|B1;l<|`  
vU8FHVytV  
private String sSiteURL; //Site's URL 7i+!^Qj?y  
private String sFilePath; //Saved File's Path M]4=(Vv+5  
private String sFileName; //Saved File's Name h[-d1bKwS  
private int nSplitter; //Count of Splited Downloading File 
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aX[1H6&=7  
x'=3&vc4  
public SiteInfoBean() P+;CE|J`X  
{//nSplitter的缺省值为5 B.Zm$JZ:  
//default value of nSplitter is 5 veX"CY`hn  
this("","","",5); z*dQIC  
} e0~sUVYf  
j2o1"  
!0!U01SWa  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /.|A  
{ [yYH>~SuwZ  
sSiteURL= sURL; :Er^"9'A2  
sFilePath = sPath; :!+}XT7)/  
sFileName = sName; u^aFj%}]L  
this.nSplitter = nSpiltter; n,&/D  
4[LLnF--  
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} #LN5&i;s  
!sfXq"F  
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public String getSSiteURL() 7|+|\7l#  
{ ,
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return sSiteURL; [w&#+h-q  
} O2`oe4."vd  
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f.aB?\"f6  
public void setSSiteURL(String value) Uw2,o|=O  
{ ( K6~Tj  
sSiteURL = value; `x{.z=xC  
} Sc4obcw%  
LC,*H0  
S1 EEASr!}  
public String getSFilePath() [5?4c'Ev  
{ (xZr ]v ]U  
return sFilePath; Ge^zX$.'  
} 0kNe?Xi  
=9qGEkd3  
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public void setSFilePath(String value) u0bfX,e2U  
{ ?Do^stq'4  
sFilePath = value; b)o
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} _KB{J7bs<a  
V>b2b5QAH,  
}J ei$0x  
public String getSFileName() mQd4#LJ_  
{ _pz,okO[V  
return sFileName; K0EY<Ltq  
} ]6$,IKE7  
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qj~flw1:  
public void setSFileName(String value) mF[o*N*  
{ lZ|L2Yg3uB  
sFileName = value; ||-nmOy  
} uipq=Yp.  
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jOUK]>ox:  
public int getNSplitter() DA<F{n.Z:  
{ YSR mt/  
return nSplitter; !_CX2|  
} kzZDtI)  
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h>}ax\h  
public void setNSplitter(int nCount) H~A"C'P3#  
{ K0w<[CO  
nSplitter = nCount; w)+wj[6 E  
} A6Ghj{~  
} 9R9__w;  
-PNi^ K_  
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/* Y/.AUN Z  
**Utility.java &+mV7o  
*/ V]79vC  
package NetFox; aWyUu/g<A`  
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public class Utility { 63W{U/*aao  
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public Utility() Fi mN?s  
{ >_XOc  
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s}6+8fE"  
} ze`1fO|%  
6iG(C.b  
//线程睡眠 Zy^=fM  
public static void sleep(int nSecond) DH 6q7"@  
{ n;wwMMBM  
try{ yL0f1nS  
Thread.sleep(nSecond); f|OI`  
} Vclr)}5  
catch(Exception e) Pm4e8b  
{ 6+.>5e  
e.printStackTrace (); a:85L!~:l  
} *HR+a#o  
} 9B /s  
{P-xCmZ~Wt  
//日志 8zY)J#  
public static void log(String sMsg) .*BA 1sjE  
{ #~L!pKM  
System.err.println(sMsg); 5sCFzo<=vh  
} ;HDZ+B  
S}[l*7  
3y99O $EAc  
public static void log(int sMsg) KU-'+k2s;p  
{ ; e@gO  
System.err.println(sMsg); ipobr7G.SD  
} i3#'*7f%j  
} 8".2)W4*  
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$.pTB(tO  
/* NmJ`?-Z  
**TestMethod.java @Mm/C?#*O  
*/ jpRBER_X  
package NetFox; *i^`Dw^~y  
h4_b!E@  
[)^mBVht  
public class TestMethod { GF8 -_X  
sYJL-2JX  
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public TestMethod() F@Q^?WV  
{ ///xx/weblogic60b2_win.exe WmeKl  
try{ s=Df `  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >!L&>OOx  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [E7MsX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^T:gb]i'Qa  
fileFetch.start(); ?]c+j1i  
} 8V9[a*9  
catch(Exception e){e.printStackTrace ();} \q "N/$5{f  
ef=K_, _  
<:&de8bT  
} =.*98  
`1Zhq+s  
OR:[J5M)  
public static void main(String[] args) qz!Ph5(  
{ _T5)n=|  
new TestMethod();  B/G-Yh$E  
} /.Fj.6U5  
} _%~$'Hy  
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