http断点续传简单实现（java)

/* |I}+!DDuv  
**SiteFileFetch.java a1`cI5
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*/ .:ZXtU  
package NetFox; &iOtw0E  
import java.io.*; Hm*vKFhz  
import java.net.*; L||yQH7n  
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public class SiteFileFetch extends Thread { 1:!rw,Jzl`  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 3Gl]g/  
long[] nStartPos; //开始位置 otSPi7|k  
long[] nEndPos; //结束位置 rgzI  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?+O|mX}`-  
long nFileLength; //文件长度 d95N$n   
boolean bFirst = true; //是否第一次取文件  GQ0(&I  
boolean bStop = false; //停止标志 %B&?D@  
File tmpFile; //文件下载的临时信息 I*t)x,~3  
DataOutputStream output; //输出到文件的输出流 ~9 WJrRWB  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /Z " 4[  
public SiteFileFetch(SiteInfoBean bean) throws IOException O|&TL9:  
{ U9o*6`"o  
siteInfoBean = bean; Hs}"A,V  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); DsW`V~T  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]2Fo.n  
if(tmpFile.exists ()) FFeRE{,  
{ |J Q:.h  
bFirst = false; j'*p  
read_nPos(); x\hn;i<  
} !J=;Z9  
else TJ[jZuT:  
{ 0*;9CH=BE  
nStartPos = new long[bean.getNSplitter()]; :5K~/=6x  
nEndPos = new long[bean.getNSplitter()]; f76|  
} 6>BDA?  
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} v~2XGm  
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public void run() .(dmuV9  
{ /9+A97{  
//获得文件长度 A Wh*<H  
//分割文件 lZA>L, \d  
//实例FileSplitterFetch aho<w+l@  
//启动FileSplitterFetch线程 3zA=q[C  
//等待子线程返回 y]pN=<*h5  
try{ ]6%%X+$7  
if(bFirst) Q
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{ `?o1cf A  
nFileLength = getFileSize(); l&sO?P[ /  
if(nFileLength == -1) Xf_tj:eO~  
{ 5-5(`OZ{'  
System.err.println("File Length is not known!"); 1xdESorX(  
} _IKP{WNB  
else if(nFileLength == -2) @j\?h$A/  
{ v8vh~^X%P  
System.err.println("File is not access!"); ({_:^$E\  
} )Kk(P/s  
else Fma`Cm.  
{ ;*4tVp,  
for(int i=0;i<nStartPos.length;i++) t6%xit+  
{ FP'u)eU&3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); SeZT4y*=  
} GE~(N N  
for(int i=0;i<nEndPos.length-1;i++) E2h;hr;W  
{ WQLHjGehe  
nEndPos = nStartPos[i+1]; t2-nCRXEP  
} k`7.p,;}U  
nEndPos[nEndPos.length-1] = nFileLength; Nzi/3r7m  
} R3{*v =ov  
} %AEK[W+0  
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//启动子线程 t1:
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8/>wgY  
for(int i=0;i<nStartPos.length;i++) $>h!J.t  
{ ,F?~'-K  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %hQM
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {c\oOM<7  
nStartPos,nEndPos,i); YKw!pu=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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fileSplitterFetch.start(); 1^60I#Vr@  
} =wlm  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o9T@uWh+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \+?,c\x  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S1az3VJI\  
nEndPos = " + nFileLength); 8MeO U  
// fileSplitterFetch[nPos.length-1].start(); r8 Zyld_@  
x^#6>oOR  
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//等待子线程结束 dp UdFuU"  
//int count = 0; LA;V}%y?  
//是否结束while循环 Xv-1PY':pA  
boolean breakWhile = false;  UE&C  
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while(!bStop) iFwyh`Bcg  
{ YM`:L  
write_nPos(); #GY&$8.u*  
Utility.sleep(500); ezg^5o;  
breakWhile = true; p'Y&Z?8  
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for(int i=0;i<nStartPos.length;i++) G>[ NZE  
{ ! =\DC,-CB  
if(!fileSplitterFetch.bDownOver) s#
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{ u8<&F`7j  
breakWhile = false; ;*wT,2;  
break; ^EC)~HP@C  
} yBPt%EF  
} }rKJeOo^x?  
if(breakWhile) Fi?32e4KI5  
break; bRK CY6  
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//count++; ?ae[dif  
//if(count>4)  4]D
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// siteStop(); z\Pe{J  
} {8!ZKlB  
{?@t/.4[W3  
F=-uDtQ<N  
System.err.println("文件下载结束！"); .Ca"$2  
} WA]%,6  
catch(Exception e){e.printStackTrace ();} :Wyn+  
} F_Z&-+,*3t  
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//获得文件长度 ih+*T1#:(  
public long getFileSize() IFd )OZ5  
{ IdV,%d{  
int nFileLength = -1; ,YP1$gj  
try{ YM
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URL url = new URL(siteInfoBean.getSSiteURL());
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zp7V\W; &  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3~[`[4n^  
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int responseCode=httpConnection.getResponseCode(); <&qpl0U)Y  
if(responseCode>=400) P3>..fhoW  
{ 3bbp>7V!  
processErrorCode(responseCode); &Q-[;  
return -2; //-2 represent access is error H Z;ZjC*  
} w+Z--@\  
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String sHeader; 5u2{n rc  
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for(int i=1;;i++) lv<iJH\  
{ .-SDo"K.h  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); g  ,/a6M  
//Utility.log(in.readLine()); D~G5]M,}$  
sHeader=httpConnection.getHeaderFieldKey(i); ]}mly`Fw  
if(sHeader!=null) d\~p5_5.  
{ L.C ^E7;Z_  
if(sHeader.equals("Content-Length")) z
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{ x4CtSGG85f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); BA~a?"HS  
break; T"L0Iy!k;  
} Ys"|</;dbj  
} ,vY)n6  
else uL2"StW  
break; 1*C:hg@  
} Zu\p;!e  
} Q0pC4WJ`  
catch(IOException e){e.printStackTrace ();} vOos*&  
catch(Exception e){e.printStackTrace ();} 1a7!4)\  
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Utility.log(nFileLength); k_,MoDz  
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return nFileLength; jP1$qhp  
} bjPka{PBj  
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//保存下载信息（文件指针位置） HG2N-<$  
private void write_nPos() -'I _*fu  
{ k4S} #!  
try{ l%rx#;=u  
output = new DataOutputStream(new FileOutputStream(tmpFile)); cqeR<len  
output.writeInt(nStartPos.length); /SnynZ.q  
for(int i=0;i<nStartPos.length;i++) mgy"|\]  
{ g d  z  
// output.writeLong(nPos); aRbx   
output.writeLong(fileSplitterFetch.nStartPos); k1wCa^*gc  
output.writeLong(fileSplitterFetch.nEndPos); "e~k
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} S3SV.C:z>  
output.close(); ;knd7SC  
} |J:$MX~  
catch(IOException e){e.printStackTrace ();} xKY$L*  
catch(Exception e){e.printStackTrace ();} cvKV95bn  
} Qm $(  
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//读取保存的下载信息（文件指针位置） }0$mn)*k  
private void read_nPos()
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{ ;4!=DFbU  
try{ }c} ( 5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fs&,
w  
int nCount = input.readInt(); ]\OWZ{T'j  
nStartPos = new long[nCount]; W@l+ciZ_  
nEndPos = new long[nCount]; k]Zo-xh4  
for(int i=0;i<nStartPos.length;i++) #;d)?  
{ d4%dIR)  
nStartPos = input.readLong(); s0r"N7~  
nEndPos = input.readLong(); ([Ebsj  
} fGb7=Fk  
input.close(); I[ai:   
} Z
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catch(IOException e){e.printStackTrace ();} Ka
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catch(Exception e){e.printStackTrace ();} `8,w[o oC2  
} =K:(&6f<t  
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private void processErrorCode(int nErrorCode) sYI~dU2H  
{ +)gGs#2X  
System.err.println("Error Code : " + nErrorCode); Wdo#?@m  
} ,E&Bn8L~O  
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//停止文件下载 M:_!w[NiLp  
public void siteStop() Xtft*Z  
{ 5^>n5u/  
bStop = true; _().t5<  
for(int i=0;i<nStartPos.length;i++) r:-WzH(Ms  
fileSplitterFetch.splitterStop(); ; yyO0Ha  
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} \k;U}Te<  
} k5a\Sq}  
//负责部分文件的抓取 &Cq{ _M  
**FileSplitterFetch.java .!i0_Rv5x  
*/ P<u"97@8a  
package NetFox; 6^sHgYR  
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import java.io.*; 4b4QbJ$  
import java.net.*; eZNitGaU  
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public class FileSplitterFetch extends Thread { Vu[:A  
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String sURL; //File URL R uLvG+  
long nStartPos; //File Snippet Start Position ~Eq\DK  
long nEndPos; //File Snippet End Position ]M3#3Ha"  
int nThreadID; //Thread's ID ]NtSu%u  
boolean bDownOver = false; //Downing is over S8%n.<OB
 
boolean bStop = false; //Stop identical kg3ppt  
FileAccessI fileAccessI = null; //File Access interface h~w4, T  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException RlsVC_H\  
{ Zm(dY*z5:J  
this.sURL = sURL;
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this.nStartPos = nStart; f jI#-  
this.nEndPos = nEnd; Wr>(#*r7q  
nThreadID = id; H?uukmZl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4\p-TPM  
} x l0DN{PG  
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public void run() zE`R,:VI  
{ ;
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while(nStartPos < nEndPos && !bStop) /)9W1U^B  
{ Kd3QqVJBz1  
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try{ nJJs%@y  
URL url = new URL(sURL); cXN _*%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qX$u4I!,  
httpConnection.setRequestProperty("User-Agent","NetFox"); dig~J\  
String sProperty = "bytes="+nStartPos+"-"; KFDS q"j  
httpConnection.setRequestProperty("RANGE",sProperty); |y"jZT6R}t  
Utility.log(sProperty); TY.FpW  
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InputStream input = httpConnection.getInputStream(); %M&3VQ9w  
//logResponseHead(httpConnection); aqMc6N`z  
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byte[] b = new byte[1024]; zoP%u,XL  
int nRead; @Z;
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F Z!J  
{ ++8_fgM  
nStartPos += fileAccessI.write(b,0,nRead); lJ{V
  
//if(nThreadID == 1) 1$ML#5+,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mJC3@V s  
} PJgp
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#U=;T]!'$  
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Utility.log("Thread " + nThreadID + " is over!"); 4:mCXP,x  
bDownOver = true; kIvvEh<L=  
//nPos = fileAccessI.write (b,0,nRead); <\@1Zz@ms  
} }B q^3?,#{  
catch(Exception e){e.printStackTrace ();} 47U
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} f:xWu-  
} dvjTyX  
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//打印回应的头信息 (][LQ6
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public void logResponseHead(HttpURLConnection con) d~*TIN8Ke~  
{ {8@\Ij  
for(int i=1;;i++) N[Sb#w`[/  
{ !e3YnlE  
String header=con.getHeaderFieldKey(i); Q_zr\RM>  
if(header!=null) 4tXSYHd3  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 1
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Utility.log(header+" : "+con.getHeaderField(header)); =Q(vni83<  
else DjHp+TyT  
break; 8)xt(~qF  
} ~rv
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} $/_qE  
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public void splitterStop() VC-
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{ (j&A",^^S  
bStop = true; (/h5zCc/v  
} rt4Z;  
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8
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} xh0xSqDM  
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-<N&0F4|*  
/* K`k'}(vj  
**FileAccess.java nWWM2v  
*//文件访问(定位，写) 4MW ]EQ-  
package NetFox; uQeu4$k!  
import java.io.*; bAF )Bli  
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public class FileAccessI implements Serializable{ )`HA::  
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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 $Ui&D I  
RandomAccessFile oSavedFile; .ve *Vp
  
long nPos; +
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public FileAccessI() throws IOException -5>NE35Cto  
{ =%qEf   
this("",0); @"|i"Hk^  
} "uD=KlA  
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public FileAccessI(String sName,long nPos) throws IOException UAYd?r  
{ 3qMNl>>  
oSavedFile = new RandomAccessFile(sName,"rw"); 4]XI"-M^D  
this.nPos = nPos; @q8an  
oSavedFile.seek(nPos); !3}deY8;#  
} >HTbegi
 
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public synchronized int write(byte[] b,int nStart,int nLen) :tGYs8UK  
{ 61K"(r~  
int n = -1; ..KwTf  
try{ k#)
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oSavedFile.write(b,nStart,nLen); MagMZR  
n = nLen; G?hK9@ |v  
} h##WA=1QZ  
catch(IOException e) U/w.M_S  
{ O\beKBT;  
e.printStackTrace (); 'ks{D(`  
} HKmcQM  
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return n; [CN$ScK,  
} $3P`DJo  
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} K|^wc$  
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/* FY#!
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**SiteInfoBean.java =@r--E  
*/ qfL-r,XS`F  
package NetFox; d*]Ew=^L  
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public class SiteInfoBean { sQ1jrkm  
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private String sSiteURL; //Site's URL 5cfA;(H  
private String sFilePath; //Saved File's Path [ygF0-3ND  
private String sFileName; //Saved File's Name +m$5a YX  
private int nSplitter; //Count of Splited Downloading File #V_GOy1-  
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2WCLS{@'  
public SiteInfoBean() e%6{ME 3  
{//nSplitter的缺省值为5 $\\lx_)  
//default value of nSplitter is 5 {aDFK;qG.  
this("","","",5); )pgrl  
} `y!/F?o+!  
>-cfZ9{!  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  '3,\@4  
{ 0Xl%uF+w  
sSiteURL= sURL; \cySWP[  
sFilePath = sPath; 'fW#7W  
sFileName = sName; :pC;`iQ  
this.nSplitter = nSpiltter; 'Cg{_z.~c  
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i g71/'D  
} X>l*v\F9  
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public String getSSiteURL() `rFAZcEj%  
{ mP}#Ccji?  
return sSiteURL; Np,2j KF(  
} =,/D/v$m'2  
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public void setSSiteURL(String value) ecHP &Z$  
{ Wk7WK` >i  
sSiteURL = value; #G;X' BN  
} q~Jq/E"f  
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public String getSFilePath() z@h~Vb&I  
{ s3QEi^~
 
return sFilePath; "^rNr_  
} wyY*:{lZ  
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public void setSFilePath(String value) -T_\f?V88  
{ _j ;
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sFilePath = value; t&RruwN_;  
} O!F]^'!  
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public String getSFileName() 4<v;1   
{ S*t%RZ~a  
return sFileName; Y 62r  
} :L$4*8@`+  
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public void setSFileName(String value) HD-Erop  
{ :c8^db`"  
sFileName = value; m4/er539T  
} Z85|I.mr  
La,QB3K/  
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public int getNSplitter() ?d-70pm  
{ JLm @Ag  
return nSplitter; R}{GwbF_\  
} 0i@:KYP  
><Z'D  
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public void setNSplitter(int nCount) .9M
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{ U[8{_h<#  
nSplitter = nCount; fE25(wCz7  
} Yp5L+~J[  
} =3'(A14C=  
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/* SkP[|g'56  
**Utility.java `deYi2z  
*/ R]L2(' B  
package NetFox; []p"3i  
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public class Utility { rla:<6tt  
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public Utility() @$U 
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{ vDE |sT  
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} T\sNtdF`:  
t4K56H.L?  
//线程睡眠 C0m\SNR  
public static void sleep(int nSecond) =ApY9`  
{ \ TL82H@D  
try{ k0ItG?C
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Thread.sleep(nSecond); *\ECf.7jz  
} ExrY>*v  
catch(Exception e) P6Xp<^%E  
{ w|Q
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e.printStackTrace (); S+T|a:]\7  
} X"/~4\tJ"  
} q=0 pQ1>  
%z)EO9vtr  
//日志 J$[Q?8 ka  
public static void log(String sMsg) ^gg!Me
 
{ E(Gr0#8  
System.err.println(sMsg); 3|eUy_d3  
} 9g@NcJ]  
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Yj8&  
public static void log(int sMsg) dY'Y5Th~  
{ n|KKby.$
  
System.err.println(sMsg); qgexb\x\4  
} e\N0@  
} -9&g[  
]|LgVXEpx  
z8iENECwj  
/* GX38~pq  
**TestMethod.java 08r[K(bfb,  
*/ B,y3] g6u  
package NetFox; -!R l(if  
&?T${*~  
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public class TestMethod { 0wvU?z%WK  
[W(Y3yyY  
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public TestMethod() S0xIvzS  
{ ///xx/weblogic60b2_win.exe Vy;_GfT$  
try{ T`Hw49  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +x]e-P%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); - L`7+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); k3yxx]Rk/  
fileFetch.start(); 4ftj>O  
} Q8Te'1Ln!  
catch(Exception e){e.printStackTrace ();} l1RlYl5  
`|,tCM&-  
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} l<N?'
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public static void main(String[] args) cx:jUsb6  
{ (xUFl
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new TestMethod(); { _X#f
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} #pa\2d|  
} 8S=c^_PJ  
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