http断点续传简单实现（java)

/* MIF[u:&  
**SiteFileFetch.java %@93^q[\2  
*/ E)wT+\  
package NetFox; jjT2k  
import java.io.*; s4`*0
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import java.net.*; X]MM7hMuR  
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, )pt_"-XA  
public class SiteFileFetch extends Thread { jQeE07g  
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SiteInfoBean siteInfoBean = null; //文件信息Bean A|_%'8  
long[] nStartPos; //开始位置 'Oy5G7^R  
long[] nEndPos; //结束位置 F"f}vl  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Doc'7P  
long nFileLength; //文件长度 G%8)6m'3
 
boolean bFirst = true; //是否第一次取文件 b;`#Sea  
boolean bStop = false; //停止标志 T{{AZV"pB  
File tmpFile; //文件下载的临时信息 oy2dA  
DataOutputStream output; //输出到文件的输出流 V<NsmC=g  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Ta\8>\6  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^AjYe<RU}  
{ 9q)nNX<$)  
siteInfoBean = bean; M= q~EMH  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;/^]|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); J(&M<<%  
if(tmpFile.exists ()) (zro7gKked  
{ ])ALAAIc-  
bFirst = false; vb.Y8[  
read_nPos(); < J<;?%
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} &~JfDe9IS  
else GKsL~;8"  
{ sHPwW5j/o'  
nStartPos = new long[bean.getNSplitter()]; >5~Zr$  
nEndPos = new long[bean.getNSplitter()]; W "\tkh2  
} b^l -*4  
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} zr;Y1Xt4  
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public void run() pJ$N@ID  
{ e"s{_V  
//获得文件长度 Va/@#=,q]  
//分割文件 Rqb{)L X*  
//实例FileSplitterFetch (|a$N.e&K  
//启动FileSplitterFetch线程 {?>bblw/d  
//等待子线程返回 hNq8 uyKx  
try{ .t^UK#@#4  
if(bFirst) w1"gl0ga$  
{ &W)+8N,L  
nFileLength = getFileSize(); ]dGr1ncu  
if(nFileLength == -1) i^s`6:rNu  
{ 1y)$[e   
System.err.println("File Length is not known!"); Gkodk[VuLs  
} rz[uuY7  
else if(nFileLength == -2) hV>4D&<  
{ ZXsY-5$#d-  
System.err.println("File is not access!"); WDoKbTv  
} )S wG+k,  
else SN[L4}{  
{ _8NEwwhc  
for(int i=0;i<nStartPos.length;i++) q(jkit~`A  
{ Kixr6\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "3Xv%U9@  
} )ZgE
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for(int i=0;i<nEndPos.length-1;i++) b5n]Gp  
{ }W__ffH  
nEndPos = nStartPos[i+1]; oXQ<9t1(  
} iBtjd`V*  
nEndPos[nEndPos.length-1] = nFileLength; Q2[prrk%j  
} bQ^DX `o6P  
} zU4V^N'  
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//启动子线程 )O2Nlk~l&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t> x-1vf%  
for(int i=0;i<nStartPos.length;i++) !e:iB7<  
{ 5M<'A=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8z
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #90[PAS
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nStartPos,nEndPos,i); *%OYAsc  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cD'HQ3+  
fileSplitterFetch.start(); s.R-<Y3  
} xb+RRTgj  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \uU=O )  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); N"Qg\PS_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4GU/V\e|  
nEndPos = " + nFileLength); Q)LXL.0h  
// fileSplitterFetch[nPos.length-1].start(); T}L^CU0  
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//等待子线程结束 ;~Q  
//int count = 0; AfbB~LlBq  
//是否结束while循环 7Sg
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boolean breakWhile = false; W>5vRwx00  
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while(!bStop) X q}Ucpj  
{ f7XQ~b  
write_nPos(); ||-nmOy  
Utility.sleep(500); Jv_.itc  
breakWhile = true; fm(mO%  
B :.@Qi^  
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for(int i=0;i<nStartPos.length;i++) kzZDtI)  
{ KQG-2oW  
if(!fileSplitterFetch.bDownOver) O1GDugZ  
{ G'ij?^?  
breakWhile = false; R)0N0gH
 
break; \~JNQ&_o  
} ?PBa'g  
} QGs1zfh
*  
if(breakWhile) T>}0) s  
break; Bk?8
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T n"e  
bA}AD`5  
//count++; {Ge+O<mD  
//if(count>4) z]^+^c_  
// siteStop(); D Irgq|8  
} 96(R'^kNX  
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System.err.println("文件下载结束！"); ShQ|{P9  
}
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catch(Exception e){e.printStackTrace ();} )PR3s1S^  
} 9n1ZVP.a
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//获得文件长度 PJzc=XPU  
public long getFileSize() +7,8w  
{ '.?^uM  
int nFileLength = -1; b2N6L2~V  
try{ 6X/wdk  
URL url = new URL(siteInfoBean.getSSiteURL()); qE )Y}oN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); taweGc%~  
httpConnection.setRequestProperty("User-Agent","NetFox"); F\a]n^ Y  
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int responseCode=httpConnection.getResponseCode(); g>so R&*  
if(responseCode>=400) 9YB2e84j  
{ !; IJ   
processErrorCode(responseCode); 9A~>`.y
 
return -2; //-2 represent access is error QV7,G9  
} cv}aS_`f  
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String sHeader; RctU'T  
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for(int i=1;;i++) >R!"P[*  
{ l^\(ss0~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U4BqO :sd  
//Utility.log(in.readLine()); bmu6@jT  
sHeader=httpConnection.getHeaderFieldKey(i); [F+(^- (  
if(sHeader!=null) Y9
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{ cJCU*(7&  
if(sHeader.equals("Content-Length")) k<H%vg>{~s  
{ \)OEBN`9#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !xu9+{-  
break; cFK @3a  
} av-#)E  
} h4_b!E@  
else [)^mBVht  
break; GF8 -_X  
} we3tx{j  
} hq=,Z1J  
catch(IOException e){e.printStackTrace ();} #ly@;!M  
catch(Exception e){e.printStackTrace ();} OF[?Z  
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Utility.log(nFileLength); OsQkA2=  
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return nFileLength; >H>gH2qp  
} q/NY72tj0  
#EDEYEW7  
9Hd;353Q  
//保存下载信息（文件指针位置） =.*98  
private void write_nPos() `1Zhq+s  
{ OR:[J5M)  
try{ qz!Ph5(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]dSK wxk  
output.writeInt(nStartPos.length); p~&BChBl!=  
for(int i=0;i<nStartPos.length;i++) i
ib  
{ 5u r)uz]w8  
// output.writeLong(nPos); UZGDdP  
output.writeLong(fileSplitterFetch.nStartPos); }g|nz8
  
output.writeLong(fileSplitterFetch.nEndPos); 5{d\uE%'p  
} %d1draL  
output.close();  |t))u`~  
} }u%"$[I}  
catch(IOException e){e.printStackTrace ();} |S&5es-yW  
catch(Exception e){e.printStackTrace ();} <_Eg?ePW#  
}  %v+=;jw  
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//读取保存的下载信息（文件指针位置） 2C$R4:Ssw)  
private void read_nPos() & ze>X  
{ (CJ.BHu]  
try{ 9@K.cdRjQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .$&Q[r3Lu  
int nCount = input.readInt(); im]g(#GnKh  
nStartPos = new long[nCount]; G,XPT,:%  
nEndPos = new long[nCount]; d;7uFh|o  
for(int i=0;i<nStartPos.length;i++) m}3gZu]  
{ s =Umj'1k  
nStartPos = input.readLong(); ?<U
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nEndPos = input.readLong(); =Q<L eh=G  
} kkS~4?-*  
input.close(); @%hCAm  
} h1[WhBL-O  
catch(IOException e){e.printStackTrace ();} QJn`WSw$_-  
catch(Exception e){e.printStackTrace ();} C3XmK}h  
} &
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private void processErrorCode(int nErrorCode) sbj";h=E  
{ L?5f+@0.  
System.err.println("Error Code : " + nErrorCode); \( )#e  
} }7s>B24J  
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//停止文件下载 El- ? %  
public void siteStop() >9H@|[C  
{ +9XQ[57  
bStop = true; ~Rpm-^  
for(int i=0;i<nStartPos.length;i++) ~+G#n"Pn  
fileSplitterFetch.splitterStop(); P[ r];e  
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f )Z%pgB  
} t<j^q`;@v  
} amWD-0V  
//负责部分文件的抓取 zR;X*q"T$4  
**FileSplitterFetch.java \.uc06  
*/ wQ+8\ s=  
package NetFox; LD>\#q8a*  
*Dmx&F=3,5  
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import java.io.*; dRi5hC$  
import java.net.*; B@y(.  
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public class FileSplitterFetch extends Thread { #A7jyg":  
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String sURL; //File URL #R0A= !  
long nStartPos; //File Snippet Start Position "=. t 36#  
long nEndPos; //File Snippet End Position 20RXK1So  
int nThreadID; //Thread's ID V'Kgdj  
boolean bDownOver = false; //Downing is over A3N]8?D  
boolean bStop = false; //Stop identical e({9]  
FileAccessI fileAccessI = null; //File Access interface )E#2J$TD  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3REx45M2  
{ DQ#H,\^<  
this.sURL = sURL; >LC<O.  
this.nStartPos = nStart; a]Eg!Q  
this.nEndPos = nEnd; wxg^Bq)D*R  
nThreadID = id; dy__e^qi  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 rl#vE's6.e  
} / $  :j  
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public void run() J7D}%  
{ f
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while(nStartPos < nEndPos && !bStop) "gtHTqheH  
{ [H<bh%  
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"xmP6=1  
try{ M->*{D@a  
URL url = new URL(sURL); ,#FLM`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9E2j!  
httpConnection.setRequestProperty("User-Agent","NetFox"); xkNyvqcw  
String sProperty = "bytes="+nStartPos+"-"; Rlnbdb;!k  
httpConnection.setRequestProperty("RANGE",sProperty); 1OLqL
 
Utility.log(sProperty); ?bZovRx  
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InputStream input = httpConnection.getInputStream(); Pi,QHb`>  
//logResponseHead(httpConnection); 2kAx>R  
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byte[] b = new byte[1024]; @vL20O.  
int nRead; fj7|D'c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -9
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{ }G o$ \Bk  
nStartPos += fileAccessI.write(b,0,nRead); vb 1@yQ  
//if(nThreadID == 1) O%g$9-?F0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1g##sSa6  
} b`yZ|j'ikd  
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Utility.log("Thread " + nThreadID + " is over!"); |Fm6#1A@  
bDownOver = true; BqDKT  
//nPos = fileAccessI.write (b,0,nRead); dkgSvi :!  
} YprHwL  
catch(Exception e){e.printStackTrace ();} }+o:j'jB  
} MV_Srz  
} dY?`f<*  
}bN%u3mHws  
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//打印回应的头信息 73{'kK  
public void logResponseHead(HttpURLConnection con) Q9}dHIe1E  
{ DRqZ,[!+
 
for(int i=1;;i++) o1&:r
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{ -<jL~][S  
String header=con.getHeaderFieldKey(i); v_e9}yI  
if(header!=null) J"=1/,AS  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); } VJfJ/  
Utility.log(header+" : "+con.getHeaderField(header)); vZ/6\Cz
 
else xtPLR/Z  
break; L9pvG(R%  
} lis/`B\x  
} *
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public void splitterStop()  +`7KSwa  
{ x
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bStop = true; ,+`61J3W  
} (-]r~Ol^  
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} Kvsh  
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/* y/e2l  
**FileAccess.java dz~coZ9  
*//文件访问(定位，写) vR0];{  
package NetFox; cvwhSdZu8  
import java.io.*; ThPE 0V  
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public class FileAccessI implements Serializable{ | mu+9  
3=-4%%[M@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 u%'\UmE w  
RandomAccessFile oSavedFile; G:x*BH+  
long nPos; e><5Pr
)  
7~#:>OjW  
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public FileAccessI() throws IOException \{Q?^E  
{ S+TOSjfis  
this("",0); \om%Q[F7a  
} nG_6oe*=I  
=^H4Yck/5  
eZ"
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public FileAccessI(String sName,long nPos) throws IOException Bgmn2-  
{ iC iZJ"  
oSavedFile = new RandomAccessFile(sName,"rw"); RwS@I
/  
this.nPos = nPos; T~h5B(J;  
oSavedFile.seek(nPos); "c}@V*cO<d  
} 5*[2yKsTi  
7ugZE93!  
(KvROV);  
public synchronized int write(byte[] b,int nStart,int nLen) &uC@|dbC5  
{ [AV4m   
int n = -1; eNiaM6(J  
try{ jA#/Z  
oSavedFile.write(b,nStart,nLen); ?\8?%Qk  
n = nLen; j~j\\Y  
} hHqh{:q{v  
catch(IOException e) Kx_h1{  
{ EyY.KxCB  
e.printStackTrace (); wP,JjPUt  
} fDx9iHGv  
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return n; qRbf2;  
} h*u`X>!!  
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} AkOO)0  
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/* Qp`gswvE  
**SiteInfoBean.java U-n;xX0=  
*/ AyMd:5;  
package NetFox; k
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[]s^   
l }XU59  
public class SiteInfoBean { Z$J#|  
vM_:&j_?``  
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private String sSiteURL; //Site's URL !n^OM?.
4  
private String sFilePath; //Saved File's Path ?WE  
private String sFileName; //Saved File's Name m|OO,gR  
private int nSplitter; //Count of Splited Downloading File h
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q&:=<+2"  
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public SiteInfoBean() a1Qv@p^._b  
{//nSplitter的缺省值为5 xeGb?DPu  
//default value of nSplitter is 5 \c^45<G2qA  
this("","","",5); y^o@"IYu3  
} ~}Rj$%_  
r H~" 4  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) HYmn:?H  
{ s`>[F@N7.o  
sSiteURL= sURL; [5Lz/ix=  
sFilePath = sPath; 9P{;HusNw  
sFileName = sName; Rb
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this.nSplitter = nSpiltter; -.{g}R%  
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} O#Wh TDF"  
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public String getSSiteURL() ]r_;dYa  
{ aM4k *|H?  
return sSiteURL; z2Z^~,i  
} 7=(Hy\Q5xH  
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public void setSSiteURL(String value) LY-2sa#B$-  
{ ? R>h `  
sSiteURL = value; fU!<HDh  
} 9uWY@zu  
/> 4"~q)  
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public String getSFilePath() Zdn~`Q{  
{ "1,pHR-+R  
return sFilePath;
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} 'fPdpnJ<  
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public void setSFilePath(String value) n[(Qr9  
{ }CfqG?)  
sFilePath = value; IIyI=WlpG  
} &?h,7 D;A  
b:w?PC~O  
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public String getSFileName() u_rdmyq$x/  
{ uw2hMt (N  
return sFileName; /JT#^Y  
} <vwkjCA`  
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public void setSFileName(String value) GH
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{ ~}<DG1!  
sFileName = value; H9CS*|q6r  
} B,{K*-7)MX  
be +4junf  
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public int getNSplitter() \G-KplKS  
{ &~W:xg(jN  
return nSplitter; zk( U8C+  
} l<N}!lG|  
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public void setNSplitter(int nCount) xNbPsoK  
{ yiO.z  
nSplitter = nCount; F8apH{&t  
} 50={%R  
} p/h Rk<K6  
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/* ,TFIG^Dvq  
**Utility.java `]W|8M  
*/ |6<p(i7  
package NetFox; 8]LD]h)B"  
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public class Utility { |iwP:C^\mJ  
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public Utility() V5rST +  
{ KY~-;0x  


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} w`5xrqt@  
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//线程睡眠 Sm5H_m!  
public static void sleep(int nSecond) ' MxrQ;|S  
{ ,S!azN=  
try{ O6OP =K!t:  
Thread.sleep(nSecond); F|!){=   
} 1@-Ns  
catch(Exception e) \P6$mh\T  
{ L+i(TM=  
e.printStackTrace (); ?F3h)(}  
} G nG>7f[v  
} q*9!,!e  
aca=yDs2  
//日志 &Udb9  
public static void log(String sMsg) }B1!gz$YNO  
{ ,l)^Ft`5  
System.err.println(sMsg); 1
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} .;N1N^  
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public static void log(int sMsg) <Sr  
{ d}4Y(   
System.err.println(sMsg); N}t 2Nu-  
} \7'+h5a  
} 5bgs*.s  
- RU=z!{  
|/)${*a4n
 
/* :n-]>Q>5=k  
**TestMethod.java s']Bx=  
*/ $A-J,_:T<  
package NetFox; 
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public class TestMethod { )'+8}T]xQ  
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#NryLE!/  
public TestMethod() bXNk%W[n  
{ ///xx/weblogic60b2_win.exe K>@+m  
try{ AnX%[W
"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |mw.qI|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 736Jq^T  
SiteFileFetch fileFetch = new SiteFileFetch(bean); k5kxQhPf  
fileFetch.start(); |0f>aZ  
} r<d_[
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catch(Exception e){e.printStackTrace ();} jIyB  
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 #^A*  
} c$yk s  
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public static void main(String[] args) Vo'T!e- B  
{ 2|*JSU.I  
new TestMethod(); z\%67C  
} GVYkJ0,  
} Yz+
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