http断点续传简单实现（java)

/* i?/qY&~  
**SiteFileFetch.java LscGTs,  
*/ O2+6st  
package NetFox; i1085ztN  
import java.io.*; .VqhV  
import java.net.*; 3 {V>S,O3]  
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"N;EL0=  
public class SiteFileFetch extends Thread { 1cDF!X]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean }b}m3i1  
long[] nStartPos; //开始位置 LP-o8c  
long[] nEndPos; //结束位置 ta0|^KAA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 IgzQr>  
long nFileLength; //文件长度 YR70BOxK  
boolean bFirst = true; //是否第一次取文件 NHt\ U9l'  
boolean bStop = false; //停止标志 [;N'=]`  
File tmpFile; //文件下载的临时信息 SJLis"8  
DataOutputStream output; //输出到文件的输出流 l}h!B_P'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） K:M8h{Ua  
public SiteFileFetch(SiteInfoBean bean) throws IOException +t.b` U`-  
{ AX INThJ  
siteInfoBean = bean; cNrg#Asen&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _aphkeqd  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~Ei<Z`3}7"  
if(tmpFile.exists ()) 5G#n"}T  
{ RCrCs  
bFirst = false; iscz}E,Y  
read_nPos(); TC('H[ ]  
} Sdo-nt  
else R_KH"`q  
{ Wqnc{oq|$  
nStartPos = new long[bean.getNSplitter()]; B~mj 8l4  
nEndPos = new long[bean.getNSplitter()]; wzA$'+Mb  
} aXVFc5C\  
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} 4*L_)z&4;  
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public void run() H}!r|nG  
{ #WuBL_nZ~  
//获得文件长度 !if   
//分割文件 0sqFF[i  
//实例FileSplitterFetch }C:r9?T  
//启动FileSplitterFetch线程 ;gkM{={`p  
//等待子线程返回 [
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try{ 7v kL1IA  
if(bFirst) bOB\--:]  
{ Y*^[P,+J*}  
nFileLength = getFileSize(); 0f/<7R  
if(nFileLength == -1) .H|-_~Yx|  
{ uZ5p#M_  
System.err.println("File Length is not known!"); m*pJBZxd  
} 2T35{Q!=F  
else if(nFileLength == -2) b-DvW4B  
{ 8mMQ[#0:}  
System.err.println("File is not access!"); hrn+UL:d  
} H)?z #x  
else R5D1
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{ 'V
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for(int i=0;i<nStartPos.length;i++) .]u/O`c]  
{ ,2q-D&)\Z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *g%yRU{N  
} tc! #wd+u  
for(int i=0;i<nEndPos.length-1;i++) s#11FfF`  
{ l;Wj]  
nEndPos = nStartPos[i+1]; X, n:,'  
} JI}'dU>*U:  
nEndPos[nEndPos.length-1] = nFileLength; 6N4~~O  
} L_T5nD^D  
} $I
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e= AKD#  
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//启动子线程 cr3^6HB  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <YY14p  
for(int i=0;i<nStartPos.length;i++) u_enqC3  
{ SU0 hma8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2ESo2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (HVGlw'`  
nStartPos,nEndPos,i); EwN}l  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ueudRb  
fileSplitterFetch.start(); ;TYBx24vD'  
} b=vkiO`2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z_HdISy0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \D4:Nt#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Hka2  
nEndPos = " + nFileLength); )8AXm  
// fileSplitterFetch[nPos.length-1].start(); I,tud
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^!d3=}:
0  
kmW4:EA%  
//等待子线程结束 s<Ziegmw|g  
//int count = 0; vaLSH xi  
//是否结束while循环 3BI1fXT4=j  
boolean breakWhile = false; G\i
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while(!bStop) TOt dUO  
{ V0@=^Bls  
write_nPos(); L0,'m
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Utility.sleep(500); l#o  ~W`  
breakWhile = true;
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for(int i=0;i<nStartPos.length;i++) 1zv'.uu.,  
{ 4RO}<$Nx}  
if(!fileSplitterFetch.bDownOver) ]^E?;1$f?  
{ ye&;(30Oq  
breakWhile = false; lxx2H1([  
break; 0J9x9j`&j  
} V gWRW7Se  
} 1}x%%RD_  
if(breakWhile) N8jIMb'<  
break; (QEG4&9  
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//count++; SUiOJ[5,  
//if(count>4) ^8WRqQdx  
// siteStop(); 04ui`-c(  
} 9[4xFE?|  
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System.err.println("文件下载结束！"); r!v\"6:OM  
} 5m@V#2^P  
catch(Exception e){e.printStackTrace ();} #qki  
} ch]IzdD  
*4'"2"  
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//获得文件长度 *dQSw)R  
public long getFileSize() Gc?a+T  
{ i-1op> Y  
int nFileLength = -1; MgZ/(X E  
try{ 1MFbQs^  
URL url = new URL(siteInfoBean.getSSiteURL()); &ZO0r ^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6ujWNf  
httpConnection.setRequestProperty("User-Agent","NetFox"); vM={V$D&  
4W75T2q#  
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int responseCode=httpConnection.getResponseCode(); )%TmAaj9d  
if(responseCode>=400) z{q`GwW  
{ zLQx%Yg!  
processErrorCode(responseCode); *. t^MP  
return -2; //-2 represent access is error ~%oR[B7=|  
} WJi]t93  
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String sHeader; q.vIc ?a  
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for(int i=1;;i++) `[A];]  
{ 6]N.%Y[(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 42{~Lhxt  
//Utility.log(in.readLine()); btB%[]  
sHeader=httpConnection.getHeaderFieldKey(i); hH.G#-JO  
if(sHeader!=null) x`s>*^  
{ SbZ6t$"  
if(sHeader.equals("Content-Length")) y_,bu^+*  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pg.%Pdr<$  
break; UiWg<_<t  
} 3|7QUld  
} 6!o1XQr=Z  
else xw%0>K[  
break; kfNWI#'9  
} bt *k.=p  
} N`i/mP  
catch(IOException e){e.printStackTrace ();} }Jw,>}  
catch(Exception e){e.printStackTrace ();} rqq1TRg  
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9  
Utility.log(nFileLength); ;S{(]K7i  
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return nFileLength; $]1=\I  
} Tw% 3p=  
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//保存下载信息（文件指针位置） )0MB9RMk1  
private void write_nPos() =41xkAMnk  
{ N!32 wJ  
try{ l6B@qYLZ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); d-m7}2c  
output.writeInt(nStartPos.length); K,]=6Rj  
for(int i=0;i<nStartPos.length;i++) n%-0V>  
{ g`^x@rj`E  
// output.writeLong(nPos); l%ZhA=TKQ  
output.writeLong(fileSplitterFetch.nStartPos); @o
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output.writeLong(fileSplitterFetch.nEndPos); wBzC5T%,  
} ToQ"Iy?  
output.close(); D$N/FJ8|G  
} _|p8M!  
catch(IOException e){e.printStackTrace ();} *I'yH8F
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catch(Exception e){e.printStackTrace ();} >p/`;Kq@  
} f?b"iA(6  
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//读取保存的下载信息（文件指针位置） x"(KBEK~  
private void read_nPos() xPgBV~  
{ hSMH,^Io$  
try{ ^.G$Q#y,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *A< 5*Db:F  
int nCount = input.readInt(); &zs$x?/  
nStartPos = new long[nCount]; BHw, 4#F1;  
nEndPos = new long[nCount]; eQ"E  
for(int i=0;i<nStartPos.length;i++) }
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{ 1}37Q&2  
nStartPos = input.readLong(); "j-CZ\]U|  
nEndPos = input.readLong(); q;U,s)Uz^  
} :LTN!jj  
input.close(); KG@8RtHsQ  
} F"<vaqT2  
catch(IOException e){e.printStackTrace ();} Ah<+y\C  
catch(Exception e){e.printStackTrace ();} -+5>|N#  
} s(^mZ -i  
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private void processErrorCode(int nErrorCode) IAEAhqp  
{ .l|$dE/E  
System.err.println("Error Code : " + nErrorCode); $|@ r!/W  
} Mlq.?-QgIL  
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//停止文件下载 vj*%Q(E6Pt  
public void siteStop() ,PZ ge  
{ ?8 {"x8W;  
bStop = true; 8D].MI^  
for(int i=0;i<nStartPos.length;i++) Mq8L0%j  
fileSplitterFetch.splitterStop(); E e]-qN*8  
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} ap~^Ty<>  
} a:S -  
//负责部分文件的抓取 iO[<1?  
**FileSplitterFetch.java *j-aXN/$  
*/ +*^H#|!  
package NetFox; ZN6Z~SL_i~  
>j`qh:^  
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import java.io.*; <,(,jU)j  
import java.net.*; @P"p+  
_ J[
  
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public class FileSplitterFetch extends Thread { 1.X@;  
9/;P->wy  
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String sURL; //File URL C-[1iW'  
long nStartPos; //File Snippet Start Position 'QIqBU'~  
long nEndPos; //File Snippet End Position BB'OCN  
int nThreadID; //Thread's ID ]:f%l mEy  
boolean bDownOver = false; //Downing is over &=Wlaa/,&  
boolean bStop = false; //Stop identical m6djeOl  
FileAccessI fileAccessI = null; //File Access interface 4aY|TN/|  
f9;(C4+  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException E!#WnSpnK  
{ ^H'\"9;7  
this.sURL = sURL; h}EPnC}  
this.nStartPos = nStart; :c[L3rJl  
this.nEndPos = nEnd; aATA9V  
nThreadID = id; _~ &iq1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 e]tDy0@  
} +]50DxflA  

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public void run() eIo7F m  
{ iyp=lLk  
while(nStartPos < nEndPos && !bStop) veRm2LSP  
{ ,=:D  
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try{ t_suF$  
URL url = new URL(sURL); e!r-+.i(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "}JZU!?  
httpConnection.setRequestProperty("User-Agent","NetFox"); l$'wDhN*  
String sProperty = "bytes="+nStartPos+"-"; +KEWP\r  
httpConnection.setRequestProperty("RANGE",sProperty); .%OR3"9@  
Utility.log(sProperty); ->{KVPHe{  
,=mS,r7  
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InputStream input = httpConnection.getInputStream(); Z`BK/:vo3H  
//logResponseHead(httpConnection); t.'!`5G  
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byte[] b = new byte[1024]; Rx|;=-8zg  
int nRead; 5P$4 =z91  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) RAK-UN  
{ I)W`sBL  
nStartPos += fileAccessI.write(b,0,nRead); 27< Enq]  
//if(nThreadID == 1) e NafpK  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (2 a`XwR  
} HX{`VahE  
?KI,cl  
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Utility.log("Thread " + nThreadID + " is over!"); L z1ME(  
bDownOver = true; C\/L v.  
//nPos = fileAccessI.write (b,0,nRead); UEVG0q
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} -FlzEZ  
catch(Exception e){e.printStackTrace ();} CWP2{  
} kn"(A.R  
} t@Nyr&|D  
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//打印回应的头信息 {&T_sw@[  
public void logResponseHead(HttpURLConnection con) [=]4-q6UN  
{ yEj^=pw  
for(int i=1;;i++) >u8gD6X  
{ Ezv Y"T@  
String header=con.getHeaderFieldKey(i); }I6vqG  
if(header!=null) QZ%`/\(!8_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `%Al>u5  
Utility.log(header+" : "+con.getHeaderField(header)); e01epVR;  
else az|N-?u  
break; nmi|\mof  
} 0tB0@Wj  
}  xLZG:^(I  
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public void splitterStop() ^_5r<{7/ :  
{ gy9U2Wgf|  
bStop = true; @<]Ekkg  
} 3nnJ8zQ  
{Wu$YWE*sx  
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}  XJ5.  
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/* ;K&o-y  
**FileAccess.java cXOK)g#  
*//文件访问(定位，写) f\>M'{cV  
package NetFox; P0PWJ^+,+  
import java.io.*; KX7>^Bt&k  
5vZ^0yFQ  
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public class FileAccessI implements Serializable{ 58J}{Req  
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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 BV upDGh3  
RandomAccessFile oSavedFile; \:ak ''  
long nPos; 6s/&BR  
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public FileAccessI() throws IOException 6N S201o  
{ %vhnl'  
this("",0); [ )dXIIM  
} )i^<r;_z  
}\:NuTf  
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public FileAccessI(String sName,long nPos) throws IOException > eIP.,9  
{ |! E)GahM  
oSavedFile = new RandomAccessFile(sName,"rw"); +sUFv)!4  
this.nPos = nPos; hPePB=  
oSavedFile.seek(nPos); V<uR>TD(  
}  Qq;Foa  
\(Y\|zC'0$  
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public synchronized int write(byte[] b,int nStart,int nLen) a^zibPG  
{ 0dhaAq`k  
int n = -1; c>Xs&_  
try{ .QJ5sgmh  
oSavedFile.write(b,nStart,nLen); (l-ab2'  
n = nLen; Y+*0~xm4  
} q$tUH)0  
catch(IOException e) 9-DZU,`P  
{ =4PV;>X  
e.printStackTrace (); /qGf 1MHD  
} S4Ww5G?.  
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return n; K&70{r  
} #32"=MfQn  
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} a\E:sPM'>  
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/* W!&'p
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**SiteInfoBean.java <_tT<5'[$u  
*/ \6<=$vD  
package NetFox; r)~ T@'y  
xt%7@/hiE  
/!$c/QZ  
public class SiteInfoBean { tEKmy7'#  
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private String sSiteURL; //Site's URL J)~L   
private String sFilePath; //Saved File's Path O_DtvjI'  
private String sFileName; //Saved File's Name 27"%"P.1  
private int nSplitter; //Count of Splited Downloading File |J}Mgb-4  
 4/1d&Sg  
t&CJ%XP  
public SiteInfoBean() 4K\(xd&Q  
{//nSplitter的缺省值为5 YWe"z
z  
//default value of nSplitter is 5 e5B Qr$j  
this("","","",5); .5,(_p^  
} % !>I*H  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >wBJy4:  
{ CS-uNG6  
sSiteURL= sURL; Q=T&  
sFilePath = sPath; k |%B?\m  
sFileName = sName; be-~\@  
this.nSplitter = nSpiltter; hn=[1<#^(  
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} ?)X,0P'  
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public String getSSiteURL() T{Uc:Z  
{ kO{s^_qR^c  
return sSiteURL; C #6dC0  
} ,JN8f]a^"g  
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public void setSSiteURL(String value) R>"OXFaE  
{ EC8b=B<DE  
sSiteURL = value; y2vUthRwo  
} W.0L:3<"  
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public String getSFilePath() sHl>$Qevz  
{ 7{qy7,Gp  
return sFilePath; WT
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}
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public void setSFilePath(String value) /BV03B  
{ 8o0%@5M  
sFilePath = value; hq/k*;  
} hk
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7=OQ8IM!  
'@CR\5 @  
public String getSFileName() e-*.Ca  
{ $N=N(^  
return sFileName; d[^~'V  
} -!L"'
)  

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public void setSFileName(String value) fpN- o  
{ %T9 sz4V  
sFileName = value; YxinE`u~  
} @b~fIW_3>  
{TRsd  
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public int getNSplitter() ,
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{ a~!G%})'a  
return nSplitter; Mz;[+p  
} dwv6;x  
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public void setNSplitter(int nCount) xvSuPP4 m  
{ `VL}.h  
nSplitter = nCount; ^~HQC*  
} \7 NpT}dj  
} [wB9s{CX  
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/* rf%7b8[v  
**Utility.java :4T("a5aM  
*/ W$Yc'E ;  
package NetFox; `\6?WXk3T  
e=QK}gzX  
@b3#X@e}  
public class Utility { D\YE^8/  
5rV((  
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public Utility() a9?y`{%L  
{ e<#DdpX!H~  
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} S"hTE7`  
R1W}dRE}  
//线程睡眠 Iu35#j  
public static void sleep(int nSecond) 5 VA(tzmCt  
{ K!mOr  
try{ AisN@  
Thread.sleep(nSecond); on7I l  
} q(5+xSg"gK  
catch(Exception e) Q!FLR>8  
{ ACK1@eF  
e.printStackTrace (); 0G2g4DSKD  
} ]k8/#@19  
} @i3bgx>_o  
"uPy,<l  
//日志 a%Jx `hx  
public static void log(String sMsg) 1lnU77;  
{ tB'V  
System.err.println(sMsg); U#o'H @  
} 1Fi86  
9=/N|m8.  
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public static void log(int sMsg) /+3a n9h  
{ S?0)1O  
System.err.println(sMsg); Ih[+K#t+E  
} 2`=6%s  
} Pu>N_^ C  
;bX4(CMe &  
9><mp]E4  
/* te4= S  
**TestMethod.java gX?n4Csy'  
*/ HZ*0QgW\(5  
package NetFox; 0%;146.p  
=BZ?-mIU  
KIVH!2q;  
public class TestMethod { p
'{xoV  
V8z`qEPM  
;#G%U!p  
public TestMethod() )DUL)S  
{ ///xx/weblogic60b2_win.exe R& =f:sEi  
try{ ~-F?Mc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Ok%}|/P4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |H ;+1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xkA2g[  
fileFetch.start(); I2HT2c$  
} -&[z\"T  
catch(Exception e){e.printStackTrace ();} UlQQP^Na  
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C
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} 2#_38=K=@  
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public static void main(String[] args) S9Yt1qb  
{ chAan~r[*  
new TestMethod(); %>XN%t'6aT  
} f8:$G.}i  
} i.rU&yT%  
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