http断点续传简单实现（java)

/* w> Tyk#7lw  
**SiteFileFetch.java oq=?i%'>  
*/ BM|-GErE  
package NetFox; 6U;Jg
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import java.io.*; Cf.pTYSl  
import java.net.*; "Cz
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public class SiteFileFetch extends Thread { YRg=yVo2  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 4RK.Il*d  
long[] nStartPos; //开始位置 9\AEyaJFZ  
long[] nEndPos; //结束位置 ?l)}
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 v< 65(I>  
long nFileLength; //文件长度 I>A^5nk  
boolean bFirst = true; //是否第一次取文件 V-?sek{;  
boolean bStop = false; //停止标志 U@o2gjGN  
File tmpFile; //文件下载的临时信息 m1^dT_7Z  
DataOutputStream output; //输出到文件的输出流 n/KI"qa]9  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1?/5A|?V4+  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,Hik(22  
{ yRgDhA  
siteInfoBean = bean; K$Mx}m7l  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Gk{ "O%AE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); R-g>W  
if(tmpFile.exists ()) _9}x
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{ UPfFT^=y  
bFirst = false;
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read_nPos(); O4 +SD  
}
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else b9
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{ afxj[;p!  
nStartPos = new long[bean.getNSplitter()]; m~= ]^e  
nEndPos = new long[bean.getNSplitter()]; )z?
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} 1jZDw~  
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} q5?
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public void run() \,@Yl.,+  
{ >,] eL  
//获得文件长度 Ovaj":L  
//分割文件 @w#gRQCl  
//实例FileSplitterFetch }\`-G+i{W  
//启动FileSplitterFetch线程 1OiZNuI:E  
//等待子线程返回 /VhE<}OtH  
try{ .(MbP  
if(bFirst) q/rHHuY}  
{ V<~_OF  
nFileLength = getFileSize(); v)C:E9!|  
if(nFileLength == -1) OIXAjU*N  
{ .^)C:XiW  
System.err.println("File Length is not known!"); zP{<0o  
} 5ykk11!p$  
else if(nFileLength == -2) ERX|cc  
{ .qqb>7|q  
System.err.println("File is not access!"); :C|>y4U&(s  
} _Pfx_+  
else :~0^ib<v;  
{ jOm&yX  
for(int i=0;i<nStartPos.length;i++) .Kh(F6 s  
{ p~d)2TC4#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >jrz;r  
} 3@Zz-~4Td  
for(int i=0;i<nEndPos.length-1;i++) -}N\REXE  
{ *OGXu07 !  
nEndPos = nStartPos[i+1]; P/gb+V=g!  
} iRj x];:Vu  
nEndPos[nEndPos.length-1] = nFileLength; 0oi5]f6g?8  
} Z#TgFQ3u  
} |b
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//启动子线程 YCB 3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Y9H *S*n  
for(int i=0;i<nStartPos.length;i++) MMxoKL  
{ I3zitI;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  CK!pH{n+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5rHnU<H@y  
nStartPos,nEndPos,i); G|P
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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fileSplitterFetch.start(); dn)tP6qc/  
} ZAo)_za&mH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dS;|Kl[Om  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); qLW-3W;WUH  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ">D(+ xr!)  
nEndPos = " + nFileLength); YZ%f7BUk  
// fileSplitterFetch[nPos.length-1].start(); 1(;33),P8  
++{+ #s6  
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//等待子线程结束 o%~K4 M".  
//int count = 0; CO%O<_C  
//是否结束while循环 73sAZa|  
boolean breakWhile = false; *(SBl}f4l  
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M4hN#0("4  
while(!bStop) D16;6K'{  
{
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write_nPos(); Y'a(J7
  
Utility.sleep(500); 1'U%7#;E  
breakWhile = true; X8l1xD  
_]r)6RT  
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for(int i=0;i<nStartPos.length;i++) ,cO)Sxj  
{ 2,e|,N"zN  
if(!fileSplitterFetch.bDownOver) j&G~;(DY  
{ wsGq>F~  
breakWhile = false; (_n8$3T75  
break; oJp_c  
} MVL
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} +U/"F|M  
if(breakWhile) ?oDfI  
break; Xiedgy  
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.W+4sax:  
//count++; I8%'Z>E(  
//if(count>4) ;o@`l$O   
// siteStop(); "N/K*  
} Vq7 kA "  
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System.err.println("文件下载结束！"); rMFZ#38d  
} 7<Js'\Z  
catch(Exception e){e.printStackTrace ();} (X7yNIPfA  
} d\Z4?@T<5  
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//获得文件长度 `IRT w"  
public long getFileSize() ]{U*+K%,J  
{ m)RxV@  
int nFileLength = -1; u]-El}*[  
try{ F"#*8P  
URL url = new URL(siteInfoBean.getSSiteURL()); 43Uy<%yb>}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %7wzGtM]ps  
httpConnection.setRequestProperty("User-Agent","NetFox"); &ziB#(&:H  
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int responseCode=httpConnection.getResponseCode(); M_ cb(=ey  
if(responseCode>=400) A"ph!* i{  
{ F7Yuky  
processErrorCode(responseCode); kV%y%l(6  
return -2; //-2 represent access is error pG=zGx4  
} "Ksd9,J\b  
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String sHeader; /38Pp%
 
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for(int i=1;;i++) }(O kl1  
{ t$D[,$G9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); au~gJW-  
//Utility.log(in.readLine()); 4[j) $!l`  
sHeader=httpConnection.getHeaderFieldKey(i); g+{MvSj$  
if(sHeader!=null) @d9*<>@:  
{ Du4?n8 o  
if(sHeader.equals("Content-Length")) U.
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{ uty]-k  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); yE/I)GOQjs  
break; Nq1RAM  
} V:
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} #f@53Pxb  
else $S=OmdgR  
break; SK2pOZN  
} 05DtU!3O  
} , >6X_XJQ  
catch(IOException e){e.printStackTrace ();} PSvRO%&  
catch(Exception e){e.printStackTrace ();} A#\X-8/  
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Utility.log(nFileLength); }0*7bb  
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return nFileLength; !b Km}1T  
} +<#-52br\  
#-8/|_*  

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//保存下载信息（文件指针位置） {K}+$jzGVt  
private void write_nPos() ?/g(Y  
{ *9 xD]ZZF  
try{ 4cL=f  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7X"cu6%\  
output.writeInt(nStartPos.length); e hGC N=  
for(int i=0;i<nStartPos.length;i++) Il[WXt<S  
{ e&kg[jU  
// output.writeLong(nPos); jk?(W2c#{  
output.writeLong(fileSplitterFetch.nStartPos); WbF\=;$=7  
output.writeLong(fileSplitterFetch.nEndPos); 4+Kc  
} 0J B"@U&-  
output.close(); gqamGLK  
} bEJZh%j!  
catch(IOException e){e.printStackTrace ();} "5FeP;  
catch(Exception e){e.printStackTrace ();}  #Ki@=*  
} hHQt4 r'd  
#-
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//读取保存的下载信息（文件指针位置） XPSWAp)  
private void read_nPos() ]y/:#^M+  
{ nfEk,(:  
try{ ewR0e.g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); HvU)GJ u b  
int nCount = input.readInt(); [ CY=  
nStartPos = new long[nCount]; Uk#1PcPd  
nEndPos = new long[nCount]; Y-9F*8<  
for(int i=0;i<nStartPos.length;i++) Spb'jAKj'  
{ YrX{,YtiX  
nStartPos = input.readLong(); v,! u{QP  
nEndPos = input.readLong(); =>Efrma  
} O@VmV>m  
input.close(); qIl@,8T  
} .)Q'j94Q  
catch(IOException e){e.printStackTrace ();} }0o0"J-$  
catch(Exception e){e.printStackTrace ();} Z~ (QV0}  
} }T@AoIR0t  
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private void processErrorCode(int nErrorCode) 2epL!j)Wh  
{ rx<fjA%  
System.err.println("Error Code : " + nErrorCode); P]G2gDO  
} !|]%^G  
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//停止文件下载 gw-l]@;1  
public void siteStop() V_:/#G]jeG  
{ wiZK-#\x  
bStop = true; *Co+UJjT  
for(int i=0;i<nStartPos.length;i++) &e{&<ZVR  
fileSplitterFetch.splitterStop(); 6mZFsB  
K(hf)1q  
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} 1 OX(eXF>  
} X#fI$9a  
//负责部分文件的抓取 %~@}wHMB  
**FileSplitterFetch.java 5u8 Y
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*/ Xv6s,<#\  
package NetFox; i4l?q#X  
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import java.io.*; @jfd.? RK!  
import java.net.*; N?aU<-T
n  
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public class FileSplitterFetch extends Thread {
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String sURL; //File URL zKR_P{W>^  
long nStartPos; //File Snippet Start Position \
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long nEndPos; //File Snippet End Position *
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int nThreadID; //Thread's ID H}d&>!\}F  
boolean bDownOver = false; //Downing is over TMbj]Mso  
boolean bStop = false; //Stop identical D(y=0),  
FileAccessI fileAccessI = null; //File Access interface h[Hw9$31  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3AWg43L7  
{ *@dqAr%  
this.sURL = sURL;  {sbQf7)  
this.nStartPos = nStart; RszqDm  
this.nEndPos = nEnd; mZmwCS8  
nThreadID = id; 1^vN?#Kt  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P9gIKOOx#4  
} `CO?} rW  
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public void run() S?&ntUah  
{ `Q,03W#GJ%  
while(nStartPos < nEndPos && !bStop) tONx
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{ hH>t  
(c_E*>c)  
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try{ Go8 m  
URL url = new URL(sURL); >Qr(#Bt)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \7jK6;R<  
httpConnection.setRequestProperty("User-Agent","NetFox"); S'q (Qo  
String sProperty = "bytes="+nStartPos+"-"; nF]lSg&]X  
httpConnection.setRequestProperty("RANGE",sProperty); =98@MX%P  
Utility.log(sProperty); JS}iNS'X  
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InputStream input = httpConnection.getInputStream(); y]+q mNw"+  
//logResponseHead(httpConnection); x^&D8&4^  
id'E_]r  
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byte[] b = new byte[1024]; r1f##  
int nRead; =XuBan3B>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) XX+%:
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{ M, f6UYo=  
nStartPos += fileAccessI.write(b,0,nRead); Eu2@%2}P  
//if(nThreadID == 1) 0@k)Cz[0;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f!AcBfaLr  
} R^4JM,v9x`  
Z$"E|nRN  
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Utility.log("Thread " + nThreadID + " is over!"); X|++K;rtfE  
bDownOver = true; ?U$H`[VF}  
//nPos = fileAccessI.write (b,0,nRead); K 0R<a~  
} yL{X}:;}  
catch(Exception e){e.printStackTrace ();}  [,JUC<  
} ZjLuqo  
} }f45>@uMW  
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Xy0*1$IS]  
//打印回应的头信息 ^VabXGzo#  
public void logResponseHead(HttpURLConnection con) xA/Ein0  
{ F/}(FG<'>I  
for(int i=1;;i++) M<$a OW0  
{ Mwm9{1{  
String header=con.getHeaderFieldKey(i); 2"~|k_  
if(header!=null) I54`}Npp  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xO3-I@  
Utility.log(header+" : "+con.getHeaderField(header)); 2z#gn9Wb  
else _!_%A
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break; TuR.'kE@  
} v@n0ma=  
} IHC {2 ^  
[ 'aSPA  
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public void splitterStop() \?EnTu.  
{ B
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bStop = true; 'z\$.L  
} 'Sk-L 5  
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} 3pU/Zbb,:  
,.6)y1!  
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/* [cfKvROG  
**FileAccess.java MbbKo-7F$  
*//文件访问(定位，写) ]&+,`1_q  
package NetFox; cI#! Y  
import java.io.*; )+L.$h  
^V
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public class FileAccessI implements Serializable{ mssCnr;  
SobOUly5{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9lU"m_ QT4  
RandomAccessFile oSavedFile; v#Xl  
long nPos; CQ;.}=j ,  
4arqlzlo  
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public FileAccessI() throws IOException ~Y)h[  
{ Tup2;\y  
this("",0); Z4VNm1qs  
} VV'*3/I  
"~+?xke5z  
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public FileAccessI(String sName,long nPos) throws IOException J}?:\y<  
{ P,RdYM06  
oSavedFile = new RandomAccessFile(sName,"rw"); myq:~^L ;  
this.nPos = nPos; P70]
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oSavedFile.seek(nPos); hH.X_X?d%  
} A(2!.Y 2?*  
6C@W6DR3N  
9$Dsm@tX  
public synchronized int write(byte[] b,int nStart,int nLen) gR#lRA/  
{ GeydVT-  
int n = -1; f=,(0ygt/  
try{ ]Oh8LcE#BF  
oSavedFile.write(b,nStart,nLen); 'h*^;3@*  
n = nLen; V7}3H2]^  
} LkK# =v  
catch(IOException e) oY(q(W0ze  
{ HAca'!p  
e.printStackTrace (); aK+jpi4?  
} ZvVrbj&  
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return n; VdC,M;/=Z  
} aMq|xHZ  
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} K
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&ZR}Z7E*=  
/* .?^a|]  
**SiteInfoBean.java mSFh*
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*/ D *Hy 2eZ.  
package NetFox; zQ>|`0&8   
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public class SiteInfoBean { fBw"<J{  
+#@)C?G,TF  
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private String sSiteURL; //Site's URL WJ[ybzVj  
private String sFilePath; //Saved File's Path yd+.hg&J  
private String sFileName; //Saved File's Name m2esVvP  
private int nSplitter; //Count of Splited Downloading File UZDXv=r|  
XUK!1}  
-#agWqUM|T  
public SiteInfoBean() x(r~<a[  
{//nSplitter的缺省值为5 Z!eW_""wp  
//default value of nSplitter is 5 \#%1t  
this("","","",5); -+)06BqF}  
} XhEJF !  
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e0&x?U*/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Eb.k:8?Tn  
{ X:kqX[\>  
sSiteURL= sURL; w;=g$Bn  
sFilePath = sPath; kl+^0i  
sFileName = sName; Spm7kw  
this.nSplitter = nSpiltter; _GF{Duxh  
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[PP&}.k4"  
} ih\
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*MD\YFXR  
79MF;>=tV  
public String getSSiteURL() -Ed<Kl  
{ MIx,#]C&  
return sSiteURL; X :wfm
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} :rzq[J^  
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t,,W{M|E(  
public void setSSiteURL(String value) v
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{ jBLLx{  
sSiteURL = value; hztxsvw  
} QFX/
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(@nEe?  
public String getSFilePath() )8@|+'q  
{ _|f_%S8a_=  
return sFilePath; ;,7/>Vt  
} #sHt3z)6I  
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&|Cd1z#?  
public void setSFilePath(String value) F`8B PW
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{ E=$li  
sFilePath = value; %k=c9ll@:  
} >p?Vv0*  
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7M,(!*b  
public String getSFileName() }[mLtv%&  
{ S!6 ? b5  
return sFileName; HF;$Wf+=J  
} u6MHdCJ0y  
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public void setSFileName(String value) eo&^~OVT  
{ c\DMeYrg  
sFileName = value; dBb &sA-A  
} \ Dccf_(Pb  
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public int getNSplitter() .8]buM5_G  
{ vp&N)t_  
return nSplitter; U>0~/o  
} Lc
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8{DW$ZtR  
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public void setNSplitter(int nCount) . ytxe!O  
{ 0@
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nSplitter = nCount; x%`tWE|  
} Wf{&D>  
} y"Ios:v@-  
9][A1+"  
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/* B+4WnR1%T  
**Utility.java +HkEbR'G0  
*/ I''X\/|  
package NetFox; 4WXr~?Vq9  
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public class Utility { o-
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public Utility() "?S>}G\  
{ @S)p{T5G  
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} OLE@35"v]  
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//线程睡眠 ;7U"wI_~c  
public static void sleep(int nSecond) Jix;!("  
{ _#y=T20'3  
try{ F0KNkL>&g  
Thread.sleep(nSecond); S.|%dz  
} '<1Q;3Ho  
catch(Exception e) eCwR }m?_  
{ :RDQP  
e.printStackTrace (); /NUu^ N  
} $D;-;5[-/r  
} paZcTC  
%ZTI ?a  
//日志 JlE b  
public static void log(String sMsg) u&<NBxY  
{ 5"z~
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System.err.println(sMsg); 4\y>pXML-U  
} Y@MFH>*  
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d=/a{lP\  
public static void log(int sMsg) ,lQfsntk'  
{ bYwe/sR  
System.err.println(sMsg); 9d8U
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} %h}3}p#4  
} MrhJk  
&24>9  
-5Aqf\  
/* D)bR-a_^  
**TestMethod.java T#ehJq 5  
*/ ^3ysY24Q  
package NetFox; 0pA>w8mh  
Q+Ya\1$6A  
W<M\b#  
public class TestMethod { LEA^o"NW.  
uZ+vYF^  
]]/p.#oD,  
public TestMethod() hEAP,)>F  
{ ///xx/weblogic60b2_win.exe ;_E][m  
try{ PY[!H<tt  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 79Q>t%rD[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *wV`7\@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?}<Wmy2A  
fileFetch.start(); 3`{[T17  
} 8g6G},Y0  
catch(Exception e){e.printStackTrace ();} 
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ty b-VO  
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} 
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*7K)J8kq  
jo ~p#l.'  
public static void main(String[] args) _}Ec[c  
{ &u0on)E  
new TestMethod(); R![1\Yv&
 
} -_fh=}.n+"  
} +6\1 d5  
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