http断点续传简单实现（java)

/* [T"oqO4%]  
**SiteFileFetch.java #I%< 1c%XA  
*/ >ly= O  
package NetFox; mvVVPf9  
import java.io.*; D4s*J21)D  
import java.net.*; 7 tF1g=\  
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public class SiteFileFetch extends Thread { `PSr64h
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SiteInfoBean siteInfoBean = null; //文件信息Bean E?y0UD[8J  
long[] nStartPos; //开始位置 3 C=nC  
long[] nEndPos; //结束位置 _8\Uukm  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 cmt3ceCb  
long nFileLength; //文件长度 .Y_RI&B!L  
boolean bFirst = true; //是否第一次取文件 5U|f"3&8  
boolean bStop = false; //停止标志 ijr*_=  
File tmpFile; //文件下载的临时信息 [4kx59J3b  
DataOutputStream output; //输出到文件的输出流 <%JdQ82?  
|?s%8c'w=  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） PdMx6 Ab  
public SiteFileFetch(SiteInfoBean bean) throws IOException Mb\~WUWI  
{ sa#=#0yg  
siteInfoBean = bean; KK(x)(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); on*?O O'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }tft@,dIC  
if(tmpFile.exists ()) q]<Xx{_  
{ _M:)x0("  
bFirst = false; dLD"Cx  
read_nPos(); \b.2f+;3  
} eQcy'GA06  
else Lr)h>j6\  
{ L]9!
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nStartPos = new long[bean.getNSplitter()]; PHDKx+$  
nEndPos = new long[bean.getNSplitter()]; s[n
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} 1:My8  
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} ~#I1!y~`  
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public void run() ,U>g L
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{ 7*'_&0   
//获得文件长度 :b=`sUn<X+  
//分割文件 s7FqE>#c0  
//实例FileSplitterFetch dAEz hR[=  
//启动FileSplitterFetch线程 /,Ln)?eD  
//等待子线程返回 
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try{ hx)Ed  
if(bFirst) BTjF^&`  
{ x9Gm)~  
nFileLength = getFileSize(); !\y_ik  
if(nFileLength == -1) C1p |.L?m  
{ Yr-,0${m  
System.err.println("File Length is not known!"); k49CS*I  
} WHbvb3'  
else if(nFileLength == -2) 7X|&:V.s|  
{ kG?tgO?*  
System.err.println("File is not access!"); &9o @x]) @  
} AKa{C f  
else "kP.Kx!  
{ L2{tof  
for(int i=0;i<nStartPos.length;i++) @#VxjXW^  
{ M*t@Q|$:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Ma-^
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} C9gF2ii|?  
for(int i=0;i<nEndPos.length-1;i++) of+$TKQNpN  
{ k B2+Tr  
nEndPos = nStartPos[i+1]; jf/;`br  
} &\0LR?Nh  
nEndPos[nEndPos.length-1] = nFileLength; a2dF(H  
} UY}lJHp0  
} WNm,r>6m  
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//启动子线程 qf)
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; C!qW:H  
for(int i=0;i<nStartPos.length;i++) xBB:b\  
{ akd~Z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $|(roC(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), v#-%_V>ph  
nStartPos,nEndPos,i); Ao{wd1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  M?}2  
fileSplitterFetch.start(); 0>Mm |x*5  
} QREIr |q'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6K`frt
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7acAU{Rr  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ),
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nEndPos = " + nFileLength); d:A+s>`$M  
// fileSplitterFetch[nPos.length-1].start(); s<<vHzm  
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//等待子线程结束 }
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//int count = 0; 2jx""{  
//是否结束while循环 !29 Rl`9
 
boolean breakWhile = false; xFg=Tyq:  
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} k5pfz  
while(!bStop) PCw.NJd$  
{  U,Z(h  
write_nPos(); IDLA-Vxo  
Utility.sleep(500); s)]|zu0"Ku  
breakWhile = true; OmU.9PDg-  
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for(int i=0;i<nStartPos.length;i++) :FxZdE  
{
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if(!fileSplitterFetch.bDownOver) "G`)x+<~Z8  
{ vtL)  
breakWhile = false; )}paQmy#  
break; Gc@
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} 6 _73  
} PicO3m  
if(breakWhile) @&,r|-  
break; "}PmAr e  
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//count++; RCxqqUS\C  
//if(count>4) jRgv 8n
  
// siteStop(); Q|pz].0  
} o^7NZ]m  
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System.err.println("文件下载结束！"); ^]aDLjD  
}
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catch(Exception e){e.printStackTrace ();} Qz<v. _  
} ENqJ9%sk7  
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//获得文件长度 U6M4}q(N]  
public long getFileSize() eQC`e#%  
{ _k ~bH\(  
int nFileLength = -1; Q%t8cJL  
try{ ?dxhe7m  
URL url = new URL(siteInfoBean.getSSiteURL()); [k1N`K(M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [dt1%DD`M  
httpConnection.setRequestProperty("User-Agent","NetFox"); DVpqm6$Q  
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int responseCode=httpConnection.getResponseCode(); :+[
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if(responseCode>=400) mg#+%v  
{ 2RM0ca_F  
processErrorCode(responseCode); :S
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return -2; //-2 represent access is error @8/-^Rh*  
} b,SY(Ce~g  
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String sHeader; 8.9S91]=  
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for(int i=1;;i++) :[AW  
{ 0eUsvzz15  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); B}*xrPj  
//Utility.log(in.readLine()); N2~DxVJ5cT  
sHeader=httpConnection.getHeaderFieldKey(i); $e<3z6  
if(sHeader!=null)
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{ ;itz`9T  
if(sHeader.equals("Content-Length")) /u#uC(Uwl  
{ S{ *RF)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); q$H'u[KQ06  
break; wt)tLMEv  
} tWc!!Hf2j  
} nq_sbli  
else K3\U'bRO  
break; L*L3;y|  
} %X#Wc:b  
} [>6:xGSe9X  
catch(IOException e){e.printStackTrace ();} d3Y#
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catch(Exception e){e.printStackTrace ();} E5 Y92vu  
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Utility.log(nFileLength); vT[%*)
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return nFileLength; r0S"}<8O  
} \mv7"TM  
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//保存下载信息（文件指针位置） 'VO^H68  
private void write_nPos() SJ+.i u/  
{ .!=g  
try{ 9Y-s],2V  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ym!Ia&n  
output.writeInt(nStartPos.length); [nflQW6  
for(int i=0;i<nStartPos.length;i++) =zI eZ7  
{ b]*9![_  
// output.writeLong(nPos); <EpP;  
output.writeLong(fileSplitterFetch.nStartPos); E#_}y}7JY  
output.writeLong(fileSplitterFetch.nEndPos); zFv>'1$  
} %iF< px?Vc  
output.close(); qY0GeE>N  
} %]  
catch(IOException e){e.printStackTrace ();}  8tPq5i  
catch(Exception e){e.printStackTrace ();} BIX%Bu0'f  
} )e{~x u  
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//读取保存的下载信息（文件指针位置） 59ro-nA9v  
private void read_nPos() 7?cZ9^z`w  
{ xt40hZ$  
try{ i mJ{wF  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mDj:w#q  
int nCount = input.readInt(); ^V>sNR  
nStartPos = new long[nCount]; 3QGg;
  
nEndPos = new long[nCount]; c< \:lhl  
for(int i=0;i<nStartPos.length;i++) I_eYTy-a`1  
{ A!@D }n  
nStartPos = input.readLong(); P3@
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nEndPos = input.readLong(); OGh bHa  
} q=|>r n_  
input.close(); {$Fg+~
 
} %'EOFv]  
catch(IOException e){e.printStackTrace ();} xB 4A"|  
catch(Exception e){e.printStackTrace ();} &.Yh_  
} ywCE2N<-V?  
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private void processErrorCode(int nErrorCode) l
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{ :^?ZVi59j  
System.err.println("Error Code : " + nErrorCode); 2rD`]neA  
} f*kT7PJG  
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//停止文件下载 QJ pUk%Wj  
public void siteStop() aoMQ_@0  
{ b6oPnP_3P  
bStop = true; zneK)C8&q3  
for(int i=0;i<nStartPos.length;i++) J;'?(xO3\  
fileSplitterFetch.splitterStop(); lusINILc  
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} 'du:Bxl`d4  
} (q3(bH~T)  
//负责部分文件的抓取 f{5)yZ`J*  
**FileSplitterFetch.java N.BD]_C  
*/ 4z[Z3|_V  
package NetFox; T4qbyu
i{  
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import java.io.*; Jp_{PR:&  
import java.net.*; D='/-3f!F]  
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public class FileSplitterFetch extends Thread { <@5#  
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String sURL; //File URL %E~4Ur  
long nStartPos; //File Snippet Start Position Qn<J@%  
long nEndPos; //File Snippet End Position [-1
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int nThreadID; //Thread's ID I=Ws /+  
boolean bDownOver = false; //Downing is over >MS}7Hk\  
boolean bStop = false; //Stop identical )#i]exZ  
FileAccessI fileAccessI = null; //File Access interface :]e:-JbT4z  
OFCkQEG=y>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException yq\)8Fe  
{ ~"brfjd|  
this.sURL = sURL; hSr#/dw&  
this.nStartPos = nStart; Z4bN|\I
  
this.nEndPos = nEnd; f{
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nThreadID = id; \L6U}ZQ2V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 uZ%b6+(  
} @T]gwJ  
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public void run() B
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{ >x&$lT{OY  
while(nStartPos < nEndPos && !bStop) `Z]a6@w~  
{ /]<0`nI.  
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try{ ^/mQo`[G  
URL url = new URL(sURL); : bT*cgD{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8r)eiERv  
httpConnection.setRequestProperty("User-Agent","NetFox"); %NX  
String sProperty = "bytes="+nStartPos+"-"; ?i)-K?4Sb  
httpConnection.setRequestProperty("RANGE",sProperty); BxO2w1G  
Utility.log(sProperty); [$9sr=3:  
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InputStream input = httpConnection.getInputStream(); 3 +BPqhzf  
//logResponseHead(httpConnection); qmOGsj`#  
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byte[] b = new byte[1024]; CG$S?  
int nRead; M1Od%nz3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) RE!MX>sOEq  
{ H*EQ%BLW^,  
nStartPos += fileAccessI.write(b,0,nRead); :a#]"z0  
//if(nThreadID == 1) `k_5Pz\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DV*8Mkzg  
} ?2_u/x  
7:{4'Wr@6|  
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Utility.log("Thread " + nThreadID + " is over!"); B;hc|v{(  
bDownOver = true; 0%`\8  
//nPos = fileAccessI.write (b,0,nRead); 8Tv;,a  
} A{mbL2AxwC  
catch(Exception e){e.printStackTrace ();} Rb\=\  
} (. 1<.PZp)  
} .l !:|Fd  
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SECL(@0(^  
//打印回应的头信息 BAdHGwomh  
public void logResponseHead(HttpURLConnection con) k[y{&f,  
{ 6~;fj+S  
for(int i=1;;i++) 9!gm
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{ wToz{!n  
String header=con.getHeaderFieldKey(i); J Y %B:  
if(header!=null) qC.jXU?rO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;QREwT~H  
Utility.log(header+" : "+con.getHeaderField(header)); 4UC/pGZY  
else pk: ruf`)  
break; 8y~ Jn~t  
} Nd^9.6,JU  
} '1=/G7g  
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public void splitterStop() @Eqc&v!O  
{ n?!.r c  
bStop = true; `k^ i#Nc>  
} v?fB:[dG  

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} Uu>YE0/)  
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/* Q:>;d-D|1  
**FileAccess.java Xu
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*//文件访问(定位，写) `lN1u'(:  
package NetFox; 8Tt2T} Y  
import java.io.*; 8[(c'rl|)|  
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}@SZ!-t%rD  
public class FileAccessI implements Serializable{ ruB&&C6)v  
6\OSIxJZF  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 QbxjfW"/+  
RandomAccessFile oSavedFile; (@uQ>dR:  
long nPos; g0cCw2S  
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public FileAccessI() throws IOException (}gF{@sn  
{ dm)V \?b  
this("",0); 
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} K34ca-~  
;# {XNq<1  
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public FileAccessI(String sName,long nPos) throws IOException Rk2ZdNc\  
{ \EUc1
7  
oSavedFile = new RandomAccessFile(sName,"rw"); g]X4)e]  
this.nPos = nPos; oel3H5Nz  
oSavedFile.seek(nPos); :==kC672  
} ]bhzB  
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public synchronized int write(byte[] b,int nStart,int nLen) e>uV8!u  
{ &tLg}7?iB  
int n = -1; s:jr/ j!  
try{ !i.`m-J*  
oSavedFile.write(b,nStart,nLen); 7bQ#M )}  
n = nLen; #9#N+  
} j 7a;g7.  
catch(IOException e) N#Qby4w >  
{ Uc<B)7{'  
e.printStackTrace (); _d A
-{  
} =WJ*$j(  
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return n; wV W+~DJ  
} 0O!%NL[,  
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} frc>0\  
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/* ~Jp\'P7*  
**SiteInfoBean.java 8 E.u3eS  
*/ 7I(Sa?D:  
package NetFox; ]1abz:  
31Zl"-<#-  
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public class SiteInfoBean { +]`MdOu  
_BHb0zeot  
9.#\GI ;  
private String sSiteURL; //Site's URL ;=F^G?p^  
private String sFilePath; //Saved File's Path )nQpO"+M  
private String sFileName; //Saved File's Name '
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private int nSplitter; //Count of Splited Downloading File "%qGcC
8  
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public SiteInfoBean() Z^>3}\_v  
{//nSplitter的缺省值为5 wH{lp/  
//default value of nSplitter is 5 x8b w#  
this("","","",5); /bfsC& 3  
} KB*[b  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @~QW~{y  
{ uH65DI<  
sSiteURL= sURL; gPQ2i])"Q  
sFilePath = sPath; rgu
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sFileName = sName; JS!rZi  
this.nSplitter = nSpiltter; M2my>  
]/bf#&@g`k  
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} A;Xn#t ,(K  
#*}4=  
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public String getSSiteURL() ,K3)f.ArYc  
{ ZfL\3Mn  
return sSiteURL; $MB56]W8  
} |DwI%%0(F  
:T5l0h-eC  
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public void setSSiteURL(String value) |a3)U%rUEQ  
{ **fJAANc  
sSiteURL = value; $-jj%x\}  
} <M7@JgC &  
EAj2uV  
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public String getSFilePath() w# ,:L)  
{ >9uDY+70I3  
return sFilePath; hi`\3B  
} R l^ENrv!]  
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public void setSFilePath(String value) v?
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{ m~(]\  
sFilePath = value; R
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} Z+(V'e;  
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public String getSFileName() j'X]bd'  
{ \&Mipf7a  
return sFileName; Do=*bZ;A  
} k .KN9=o  
H.'MQ  
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public void setSFileName(String value) %_KNAuM  
{ ,*@m<{DX)  
sFileName = value; kJZBQ<^  
} HZkC3$  
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public int getNSplitter() FC.y%P,  
{ l`[*b_ Xt  
return nSplitter; /V$[M  
} UStZ3A'  
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public void setNSplitter(int nCount) hz>&E,<8q  
{ _;G"{e.=  
nSplitter = nCount; & WYIfx{  
} }f;Zx)!  
} esLPJx  
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/* zX{
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**Utility.java 6}K|eUak/  
*/ WG1UvPK  
package NetFox; cCw?%qq,L  
YaFQy0t%/5  
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public class Utility { y4C_G?  
=zK7`5  
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public Utility() H9xxId?3u  
{ I,_wt+O&j  
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8N'`kd~6[  
} q/6d^&
  
hE/gul?|_  
//线程睡眠 >(<OhS(  
public static void sleep(int nSecond) B&0-~o3WP  
{ |F iL1_  
try{ i(a2FKLy  
Thread.sleep(nSecond); z5=&qo|f9l  
} Yih^ZTf]O?  
catch(Exception e) H8`K?SXU  
{ n,wLk./`  
e.printStackTrace (); dp&4G6Y<A  
} Fm#4;'x5E  
} V2u^sy  
Y(m/E.h.~  
//日志 53=VIN]  
public static void log(String sMsg) \(cu<{=rU  
{ eg3zpgZ  
System.err.println(sMsg); ME>OTs  
} |FS79Bv  
']Nw{}eS`  
v< xe(dC  
public static void log(int sMsg) j;=+5PY  
{ {[m %1O1  
System.err.println(sMsg); #6 e  
} N*|Mfpf  
} JrQd7
 
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/* Zh)Q
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**TestMethod.java G)?VC^Q  
*/ </5uB' B ^  
package NetFox; Co4QWyt:  
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public class TestMethod { t9
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public TestMethod() w-Y-;*S  
{ ///xx/weblogic60b2_win.exe ZL:nohB  
try{ _bHmcK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); JpvE c!cli  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~]*P/'-{#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j,K]TJ  
fileFetch.start(); x\]%TTps  
} w`bojM@e1  
catch(Exception e){e.printStackTrace ();} nAZuA]p}S]  
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? DWF7{1  
} ;dPyhR  
;sE;l7  
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public static void main(String[] args) u}W R1u[  
{ 9KN75<n  
new TestMethod(); AMp[f%X  
} v/ dSz/<]  
} OxqK}%=Bw  
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