http断点续传简单实现（java)

/* gG!L#J?  
**SiteFileFetch.java %4*-BCP  
*/ 40w,:$  
package NetFox; N7v7b<6  
import java.io.*; Tu"bbc  
import java.net.*; bH%k)  
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public class SiteFileFetch extends Thread { &`Oj<UyJY  
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SiteInfoBean siteInfoBean = null; //文件信息Bean gdPv,p19L  
long[] nStartPos; //开始位置 aAhXHsZ|26  
long[] nEndPos; //结束位置 t6(LO9Qc  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [H<![Z1*r  
long nFileLength; //文件长度 OGpy\0%  
boolean bFirst = true; //是否第一次取文件 ">_<L.,I  
boolean bStop = false; //停止标志 bFD vCF  
File tmpFile; //文件下载的临时信息 @ qy n[C  
DataOutputStream output; //输出到文件的输出流 SaceIV%(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <&^
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public SiteFileFetch(SiteInfoBean bean) throws IOException _4Z|O]  
{ jM]B\cvN  
siteInfoBean = bean; h8B:}_Cu  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); FOV%\=Hl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); C-O~Oil  
if(tmpFile.exists ()) $a.fQ<,\X  
{ k<(G)7'gm  
bFirst = false; HI&N&a9C  
read_nPos(); -5B>2K F  
} (cAWT,  
else 50kjX}  
{ tUU`R{=(  
nStartPos = new long[bean.getNSplitter()]; 8S/SXyS  
nEndPos = new long[bean.getNSplitter()]; u5zL;C3O  
} {BPNb{dBKr  
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} p)2 !_0  
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public void run() r&!Ebe-  
{ Bu
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//获得文件长度 y.vYT{^  
//分割文件 M~/7thP{  
//实例FileSplitterFetch R<(kiD\?]  
//启动FileSplitterFetch线程 {;mT.[  
//等待子线程返回 9BR/zQ2  
try{ R. :~e  
if(bFirst) -7-r~zmr  
{ ^#
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nFileLength = getFileSize(); 8G3CQ]G  
if(nFileLength == -1) W;L<zFFbU)  
{ d?[gd(O  
System.err.println("File Length is not known!"); VgGMlDl  
} ^EtBo7^t  
else if(nFileLength == -2) ^i+ d3  
{ _C"=Hy{  
System.err.println("File is not access!"); |y%pJdPk=  
} W3Gg<!*Uo  
else "- 2HKs  
{ WX~:Y,l+u  
for(int i=0;i<nStartPos.length;i++) b-!+Q)  
{ _UP=zW  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); x;N@_FZ7KY  
} -%f$$7  
for(int i=0;i<nEndPos.length-1;i++) 2-G6I92d  
{ }Br=eaY  
nEndPos = nStartPos[i+1]; h
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} /Uxp5 b h  
nEndPos[nEndPos.length-1] = nFileLength; G42J  
} B8Vhl:p  
} )WWqi,T}  
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//启动子线程 Df
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I'h|7y\  
for(int i=0;i<nStartPos.length;i++) Sjb[v  
{ vC#_PI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fl@=h[g#t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), x)}.@\&%  
nStartPos,nEndPos,i); &JUHm_wd&S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7l%]O}!d)  
fileSplitterFetch.start(); 1 sJtkge:  
} wmV7g7t6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O~P1d&:L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,]Gi942  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", };{Qx  
nEndPos = " + nFileLength); CU`yi.)T{  
// fileSplitterFetch[nPos.length-1].start(); ]9A@iA  
DjLSl,Z  
xVnk]:c  
//等待子线程结束 }R&5Ye  
//int count = 0; -tPia=^  
//是否结束while循环 t/$:g9V%FA  
boolean breakWhile = false; s2Rg-:7  
@"h@4q/W  
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while(!bStop) Q
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{ f[ 'uka.U  
write_nPos(); `/"*_AKAI  
Utility.sleep(500); pLdZB9oD]C  
breakWhile = true; 9M12|X\]8  
~7 w"$H8  
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for(int i=0;i<nStartPos.length;i++) )swu~Wb}U@  
{ X;/5Niv32q  
if(!fileSplitterFetch.bDownOver) e0Jz|?d=  
{ E\Qm09Dj`<  
breakWhile = false; qrr[QEFW  
break; [z[<onFIq  
} /LK,:6  
} F`Ld WA  
if(breakWhile) D$?}M>  
break; [ !<  
9 $&$Fe  
-bP_jIZF;g  
//count++; uN;]Fv@Z  
//if(count>4)
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// siteStop(); P->.eo#VG  
} hU|TP3*  
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System.err.println("文件下载结束！");  rYI7V?  
} K@<%Vc>L(  
catch(Exception e){e.printStackTrace ();} 3;%dn\ D  
} huat,zLS  
%G`GdG}T  
Wm^RfxgN/  
//获得文件长度 KD=W(\  
public long getFileSize() ,9.-A-Yw  
{ }7HR<%<7  
int nFileLength = -1; qdNt2SO  
try{ ISDeLUihY  
URL url = new URL(siteInfoBean.getSSiteURL()); #d*)W3e2{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dX;Q\  ]"  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7=@3cw H  
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h0z>dLA#2  
int responseCode=httpConnection.getResponseCode(); JwNB)e D  
if(responseCode>=400) TgjM@ir  
{ y#iQ  
processErrorCode(responseCode); BM>'w,$KL  
return -2; //-2 represent access is error dWi:V7t+  
} [/Vi*Z  
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String sHeader; /H'F4->  
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for(int i=1;;i++) Qq{>]5<  
{ %] #XIr  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); t3 rQ5m
 
//Utility.log(in.readLine()); GwM(E^AG  
sHeader=httpConnection.getHeaderFieldKey(i); <$@*'i^7Ez  
if(sHeader!=null) U][\|8i  
{ oYR OGU  
if(sHeader.equals("Content-Length")) !v\_<8  
{ ),
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); w!--K9  
break; :406Oa  
} WlHK  
} X:kr$  
else > }fw7X  
break; Bm$(4  
} y!u=]BE  
} *LOUf7`  
catch(IOException e){e.printStackTrace ();} xcM*D3  
catch(Exception e){e.printStackTrace ();} OzA'd\|  
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Utility.log(nFileLength); J.Fy0W@+k4  
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return nFileLength; "n%0L4J  
} Ql]+,^kA@  
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//保存下载信息（文件指针位置） :lE_hY  
private void write_nPos() TsF>Y""*M  
{ zEy,aa:M  
try{ TjY-C m  
output = new DataOutputStream(new FileOutputStream(tmpFile)); zPc kM)  
output.writeInt(nStartPos.length); 2Fc>6]:*  
for(int i=0;i<nStartPos.length;i++) <HB@j}qi  
{ C3:CuoE X  
// output.writeLong(nPos); U["-`:>jfp  
output.writeLong(fileSplitterFetch.nStartPos); DkJ "#8Yl=  
output.writeLong(fileSplitterFetch.nEndPos); JU3to_Io  
} #5X535'ze  
output.close(); #p7K2  
} ]$&N"&q  
catch(IOException e){e.printStackTrace ();} n^iq?u  
catch(Exception e){e.printStackTrace ();} y Q-{
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} d;hv_
h  
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//读取保存的下载信息（文件指针位置） o2rL&  
private void read_nPos() D~b_nFD  
{ ;Q>+#5H6F8  
try{ :^rt8>~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2bu>j1h  
int nCount = input.readInt(); GyF  
nStartPos = new long[nCount]; m[DCA\Mo@  
nEndPos = new long[nCount]; SLU$DW;t  
for(int i=0;i<nStartPos.length;i++) CK9FAuU  
{ R3|r`~@@  
nStartPos = input.readLong(); wl/1~!  
nEndPos = input.readLong(); ({0:1*lF@  
} *CCh\+S7m  
input.close(); VT [T
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} -?p4"[
 
catch(IOException e){e.printStackTrace ();} {Jc.49  
catch(Exception e){e.printStackTrace ();} Om_-#S  
} ^v5<*uf%m  
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private void processErrorCode(int nErrorCode) _=_<cgy1u  
{ txik{' :  
System.err.println("Error Code : " + nErrorCode); i:60|ngK  
} .$]-::&  
722:2 {  
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//停止文件下载 Hu$y8_Udw  
public void siteStop() <DZ$"t  
{ +Ze;BKZ3  
bStop = true; mtmTlGp6Lc  
for(int i=0;i<nStartPos.length;i++) k}]M`ad  
fileSplitterFetch.splitterStop(); 9Cz|?71  
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} U:0Ma6<  
} [`kk<$=,&  
//负责部分文件的抓取 w
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**FileSplitterFetch.java 2b K1.BD  
*/ /B<QYvv  
package NetFox; JbAmud,  
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import java.io.*; y96HTQ32  
import java.net.*; FfNUFx2N  
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public class FileSplitterFetch extends Thread { H[RX~Xk2E  
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String sURL; //File URL +c$:#9$ |  
long nStartPos; //File Snippet Start Position _FxeZ4\  
long nEndPos; //File Snippet End Position @{"?fqo  
int nThreadID; //Thread's ID :gn&wi  
boolean bDownOver = false; //Downing is over {H*  
boolean bStop = false; //Stop identical jG{OLF6 !  
FileAccessI fileAccessI = null; //File Access interface >f'aW  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException r{KQ3j9O  
{ IGOEqUw*  
this.sURL = sURL; l5#SOo\  
this.nStartPos = nStart; =!\Y;rk  
this.nEndPos = nEnd; ,KCxNdg^#-  
nThreadID = id; 6Ey@)p..E  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Zs4NN2~  
} !t+ 3DMPn  
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public void run() 5^K\<+{~B  
{ /0o#V-E)  
while(nStartPos < nEndPos && !bStop) ~+C)0Yn  
{ XZ@|(_Z  
*M/:W =,t  
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try{ )<lQJ#L86a  
URL url = new URL(sURL); z'7XGO'Lo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~1{ppc+  
httpConnection.setRequestProperty("User-Agent","NetFox"); E\ls- (,  
String sProperty = "bytes="+nStartPos+"-"; 3m| C8:  
httpConnection.setRequestProperty("RANGE",sProperty); gD2P)7:  
Utility.log(sProperty);  VeSQq  
'50}QY_R.  
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InputStream input = httpConnection.getInputStream(); I1Otu~%d  
//logResponseHead(httpConnection); yfal'DqKF  
9s1^hW2%Q  
7Ie=(x8):  
byte[] b = new byte[1024]; *%Fu/  
int nRead; 5+Ao.3Xn  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) txvo7?Y*4  
{  O4Q"2  
nStartPos += fileAccessI.write(b,0,nRead); je5[.VTM  
//if(nThreadID == 1) C57m{RH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q}!h(-y}5n  
} 80ox$U  
,Ha<lU2K  
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Utility.log("Thread " + nThreadID + " is over!"); '4SDAa2f  
bDownOver = true; e^'|<0J  
//nPos = fileAccessI.write (b,0,nRead); i\O^s ]  
} Ch\__t*v!  
catch(Exception e){e.printStackTrace ();} ":f]egq -  
} S+#|j  
} fY6~Z BvK  
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&36SX<vZ  
//打印回应的头信息 KK6n"&TVa  
public void logResponseHead(HttpURLConnection con) wSw> UU  
{ 6']HmM  
for(int i=1;;i++) )XHn.>]nc  
{ Lx tgf2r  
String header=con.getHeaderFieldKey(i); @mmnr?_w  
if(header!=null)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); QZtQogNy#  
Utility.log(header+" : "+con.getHeaderField(header)); rOz1tY)l0d  
else 4v`IAR?&K;  
break; .
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} #?V rt,n  
} NSBcYObX  
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public void splitterStop() #qh ,  
{ \H~zN]3^  
bStop = true; vP=68muD  
} 78Du  
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} X^Z!!KTH  
![sXR  
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/* L
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**FileAccess.java '&'m#H*:  
*//文件访问(定位，写) 9}u,`&  
package NetFox; |q58XwU `  
import java.io.*; /isalOT  
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public class FileAccessI implements Serializable{ ?3p7MjvZ  
;AE-=/<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4(|yl^w  
RandomAccessFile oSavedFile; A4'5cR9T!  
long nPos; 3+15 yEeA  
! 5NuFLOf  
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public FileAccessI() throws IOException :nQlS  
{ ]"lB!O~  
this("",0); 7jgj;%  
} w4vV#C4X  
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public FileAccessI(String sName,long nPos) throws IOException _$ivN!k  
{ bh<;px-  
oSavedFile = new RandomAccessFile(sName,"rw"); Vv45w#w;  
this.nPos = nPos; +.Ij%S[Px5  
oSavedFile.seek(nPos); e=WjFnK[x7  
} FO5a<6
 
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public synchronized int write(byte[] b,int nStart,int nLen) D%abBE1  
{ USEb} M`  
int n = -1; 0z8?6~M;<  
try{ Jsysk $R  
oSavedFile.write(b,nStart,nLen); !R"W2Z4h  
n = nLen; \gk.[={^P  
} -}9^$}PR  
catch(IOException e) TK fN`6  
{ *y!O\-\S#>  
e.printStackTrace (); })H d]a  
} /\c'kMAW!  
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return n; 4P&2Z0  
} "FWx;65CR  
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} l!F$V;R  
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/* ujZ`T0  
**SiteInfoBean.java bI55G#1G  
*/ _cX}!d!j  
package NetFox; @"-\e|[N  
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public class SiteInfoBean { )1uiY f&k  
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private String sSiteURL; //Site's URL 6 Rl[M+Q  
private String sFilePath; //Saved File's Path @PEFl"  
private String sFileName; //Saved File's Name <w{?b'/q  
private int nSplitter; //Count of Splited Downloading File /ce;-3+  
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public SiteInfoBean() d
+ jX49Vt  
{//nSplitter的缺省值为5 j#1G?MF  
//default value of nSplitter is 5 }OpUG  
this("","","",5); N/bOl~!y  
} X.eOw>.
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) rD].=.?1  
{ @-'a{hBR  
sSiteURL= sURL; Nmj)TOEPW  
sFilePath = sPath; mGjB{Q+  
sFileName = sName; *M1GVhW(+  
this.nSplitter = nSpiltter; :V(L
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v Y0bK-  
~5f&<,p!  
} \8`7E1d  
>>y`ap2%V  
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public String getSSiteURL() nm-  
{ j uA@"SG  
return sSiteURL; 2DQVl  
} tk&AZb,sP  
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public void setSSiteURL(String value) {p +&Q|  
{ )G/bP!^+(  
sSiteURL = value; Q":_\inF  
} m/KaWrw/)  
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public String getSFilePath() HwUaaK   
{ yQ$irS?  
return sFilePath; Mg;pNK\n  
} ~_
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I  
Q$E.G63Wl  
public void setSFilePath(String value) u?=mh`  
{ x>yqEdR=o  
sFilePath = value; %Mda<3P  
} (S~kyU!)0  
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nTeA=0 4  
public String getSFileName() @dWA1tM  
{ :_8K8Sa  
return sFileName; ;m]V12  
} ZcN0:xU  
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.xT?%xSi/  
public void setSFileName(String value) (a[BvJf  
{ @t%da^-HS"  
sFileName = value; .U!EA0B  
} p<mL%3s0  
7=P)`@  
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public int getNSplitter() X+4Uh I  
{ 9@*pC@I)  
return nSplitter; %xkuW]xk  
} C-YYG  
!j6k]BgZ  
^E70$yB^  
public void setNSplitter(int nCount) <Wn~s=  
{ suN6(p(.  
nSplitter = nCount; 9xQ|Uad+%  
} e>MtDJ5  
} 2{ F-@}=  
|]&3*%b@  
>z<L60S  
/* q,P.)\0A  
**Utility.java G_F_TNO
 
*/ 7X$CJ%6b  
package NetFox; iC#a+G*N_M  
1)z'-dQ-5$  
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public class Utility { +~5Lo'^  
o?a2wY^
_  
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public Utility() 0~nX
7
 
{ Ua}R3^_)a  
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} o,i_py  
fbApE  
//线程睡眠 f7&ni#^Ztj  
public static void sleep(int nSecond) GgpE"M?  
{ fzJiW@-T  
try{ @/#G2<Vp1  
Thread.sleep(nSecond); ]3v)3Wp  
} u>'0Xo9R  
catch(Exception e) +3))G  
{ ]xS%Er  
e.printStackTrace (); ie1~QQ  
} aj?ZVa6  
} ]9QXQH  
;6V~yB  
//日志 %w&+o.k/  
public static void log(String sMsg) @1j*\gYz  
{ _{o 3y"DZ  
System.err.println(sMsg); !!.@F;]W  
} jZ~girA  
JAxzXAsAR  
g3
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public static void log(int sMsg) C^$E#|E9N  
{ )v
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System.err.println(sMsg); "-:H$  
} rO}1E<g (  
} %p
\~  
Aw7N'0K9UN  
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/* ?8753{wk  
**TestMethod.java ~=yU%5 s@  
*/ }oD^tU IK  
package NetFox; 61_PSScSY  
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MgiW9@_(  
public class TestMethod { CV[9i  
|21VOPBS  
$}4ao2  
public TestMethod() rw)!>j+&A  
{ ///xx/weblogic60b2_win.exe Eq_@xT0>  
try{ 24od74\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~vYF
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O C;~ H{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); LDegJer-v  
fileFetch.start(); o"qxR'V  
} O=K0KOj  
catch(Exception e){e.printStackTrace ();} \>\ERV
Ed  
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} hrX/,D -c  
j~bNH~3  
$\m:}\%p  
public static void main(String[] args) h8WM4 PK  
{ X!V#:2JY  
new TestMethod(); GYtgw9 "Y  
} )-I/ej^  
} ]R~hzo  
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