http断点续传简单实现（java)

/* e&U$;sS`  
**SiteFileFetch.java 'SoBB:  
*/ 5`+9<8V  
package NetFox; >1;jBx>Qy%  
import java.io.*; .UQ|k,,t  
import java.net.*; doHE]gC2Uz  
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public class SiteFileFetch extends Thread { \k`9s q  
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SiteInfoBean siteInfoBean = null; //文件信息Bean W Zm8!
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long[] nStartPos; //开始位置 Rvx7}ZL!  
long[] nEndPos; //结束位置 ( $2M
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 2,`X@N`\  
long nFileLength; //文件长度 $fT5Vc]B4  
boolean bFirst = true; //是否第一次取文件 -3v\ c~  
boolean bStop = false; //停止标志 5N%d Les  
File tmpFile; //文件下载的临时信息 K:$mEB[c<  
DataOutputStream output; //输出到文件的输出流 6Aq]I$  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [+pa,^  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3di;lzGq  
{ T4p}5ew'  
siteInfoBean = bean; 6QbDU[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); KN`k+!@/7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -6s:D/t1'  
if(tmpFile.exists ()) jll:Rh(b  
{ ,>7dIJqzw  
bFirst = false; "0[`U(/  
read_nPos(); :r hB=  
} <I tS_/z  
else ~ZSX84~@u  
{ LQ4:SV'3  
nStartPos = new long[bean.getNSplitter()]; ZvT,HJ0?  
nEndPos = new long[bean.getNSplitter()]; 0m4M@94  
} OG?7( UJ  
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} aF+Lam(  
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public void run() 7x>^ip"7  
{ M'<% d[  
//获得文件长度 zEtsMU  
//分割文件 aK;OzB)  
//实例FileSplitterFetch b~:)d>s8wY  
//启动FileSplitterFetch线程 KB|mtsi  
//等待子线程返回 [r8[lkR  
try{ {.AN4  
if(bFirst) d94k  
{ Kc2y  
nFileLength = getFileSize(); gDLS)4^w  
if(nFileLength == -1) f7\X3v2W}3  
{ O!f37n-TB  
System.err.println("File Length is not known!"); +~iiy;i(  
} %sOY:>  
else if(nFileLength == -2) RH<2f5-sC!  
{ 8P-ay<6  
System.err.println("File is not access!"); `vAcCahM  
} j,^&U|!  
else Gg~0>XS  
{ JN+7oh]u  
for(int i=0;i<nStartPos.length;i++) p<L{e~{!7f  
{ MQx1|>rG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?2~fvMWu  
} [1kQ-Ko`  
for(int i=0;i<nEndPos.length-1;i++) 0>td[f  
{ XWS]4MB+vm  
nEndPos = nStartPos[i+1]; a`%`9GD  
} d/OP+yzgZ  
nEndPos[nEndPos.length-1] = nFileLength; Z^%a 1>`  
} saiXFM7J  
} 6P717[  
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//启动子线程 \|QB;7u  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; L +Uq4S^  
for(int i=0;i<nStartPos.length;i++) W0sL
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{ UH%H9; ,$]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -_5Dk'R#`  
nStartPos,nEndPos,i); ZM-P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :2S?|7U4  
fileSplitterFetch.start(); T%6JVFD  
} "X2'k@s`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]goJ- &  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a<\n$E#q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D|)_c1g  
nEndPos = " + nFileLength); lCp6UkE  
// fileSplitterFetch[nPos.length-1].start(); 06%-tAq:  
\UZGXk  
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//等待子线程结束 EMO{u  
//int count = 0; N6-7RoA+  
//是否结束while循环 '=Zm[P,  
boolean breakWhile = false; ?<3 d Fb  
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while(!bStop) "kFH*I+v  
{ pI
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write_nPos(); +vxf_*0;  
Utility.sleep(500); TBPu&+3  
breakWhile = true; I1':&l^O  
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for(int i=0;i<nStartPos.length;i++) ri8=u$!  
{ 0>SA90Q  
if(!fileSplitterFetch.bDownOver) [>a3` 0M  
{ K 'l-6JY-  
breakWhile = false; Mi|13[p{  
break; dL%*;   
} yXDjM2oR/2  
} *|W](id7e  
if(breakWhile) ZwsQ}5
 
break; `9[n5-t  
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//count++; 0{ mm%@o  
//if(count>4) F<p`)?  
// siteStop(); &}e>JgBe0  
} ,NZllnW  
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System.err.println("文件下载结束！"); z;oia!9z  
} TIiYic!_~  
catch(Exception e){e.printStackTrace ();} "i#g [x  
} 4y3c=L No  
ed',\+.uB  
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//获得文件长度 ~$K{
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public long getFileSize() DL4`j>2Ov  
{ BuRsz6n  
int nFileLength = -1; rbdrs  
try{ @H#Fzoo.  
URL url = new URL(siteInfoBean.getSSiteURL()); .lb]Xa*n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K2x2Y=  
httpConnection.setRequestProperty("User-Agent","NetFox"); Yl&[_ l  
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int responseCode=httpConnection.getResponseCode(); }FS_"0  
if(responseCode>=400) D8,8j;  
{ iy]L"7&Z2  
processErrorCode(responseCode); SF;\*]["f  
return -2; //-2 represent access is error zW#5 /*@  
} fn 'n'X|  
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String sHeader; AA^K/y  
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for(int i=1;;i++) hR|xU
p  
{ \\:%++}J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); SS%Bde&<{  
//Utility.log(in.readLine()); ]N]Fb3  
sHeader=httpConnection.getHeaderFieldKey(i); 9FSa=<0wE  
if(sHeader!=null) "1Hn?4nz5  
{ lG0CCOdQ  
if(sHeader.equals("Content-Length")) PZ6R+n8  
{ :n13v@q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [LjiLKW  
break; Xykoq"dbb  
} ^"|q~2  
} ;5X~"#%U_  
else
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break; 9F3,  
} x1g-@{8]j  
} -j<E_!t  
catch(IOException e){e.printStackTrace ();} &_:9.I1  
catch(Exception e){e.printStackTrace ();} p:nl4O/  
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Utility.log(nFileLength); [>
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return nFileLength; >>J$`0kM*  
} ,}W|cm>  
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//保存下载信息（文件指针位置） 08jk~$%  
private void write_nPos() u `xQC/  
{ g$e|y#Ic$  
try{ Cx~;oWZ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Mn&_R{{=  
output.writeInt(nStartPos.length); \Db`RvEmR  
for(int i=0;i<nStartPos.length;i++) 3S_H&>K  
{ ;\A_-a_(#  
// output.writeLong(nPos); 8%;Wyqdf]  
output.writeLong(fileSplitterFetch.nStartPos); 30WOH 'n  
output.writeLong(fileSplitterFetch.nEndPos); 9teP4H}m  
} 0/]h"5H3  
output.close(); D`G;C  
} :I&y@@UG  
catch(IOException e){e.printStackTrace ();} _XP}fx7$C  
catch(Exception e){e.printStackTrace ();} mYo~RXKGF  
} 7{M&9| aK  
q M_c-^F  
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//读取保存的下载信息（文件指针位置） u8JH~b  
private void read_nPos() _y6iR&&x  
{ UmpHae  
try{ \41/84BA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .9ZK@xM&?  
int nCount = input.readInt(); L /
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nStartPos = new long[nCount]; c0e[vrP:  
nEndPos = new long[nCount]; V0A>+  
for(int i=0;i<nStartPos.length;i++) 
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{ ;k@]"&t  
nStartPos = input.readLong(); ^bPpcm=  
nEndPos = input.readLong(); 2jhJXM=~  
} NGi)Lh|  
input.close(); :!t4.ko  
} |H5GWZ O{^  
catch(IOException e){e.printStackTrace ();} TtrO_D  
catch(Exception e){e.printStackTrace ();}
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} ,aezMbg  
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private void processErrorCode(int nErrorCode) `'iO+/;GY  
{ ;lE=7[UJ3X  
System.err.println("Error Code : " + nErrorCode); #E Bdg  
} E7R%G OH  
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//停止文件下载 _oa*E2VN  
public void siteStop() 2K/t[.8  
{ {7oPDP  
bStop = true; o8:9Yjs  
for(int i=0;i<nStartPos.length;i++) #w5%^HwO  
fileSplitterFetch.splitterStop(); tR9iFv_  
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}  Z
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} 4w9=z,  
//负责部分文件的抓取 d5LBL'/o  
**FileSplitterFetch.java 6v scu2  
*/ _0u=}tc  
package NetFox; JT<JS6vw#  
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import java.io.*; %$b}o7U"s  
import java.net.*; UzSDXhzObf  
/#{~aCOi)  
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public class FileSplitterFetch extends Thread { $;=^|I4E  
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String sURL; //File URL h5l_/vd  
long nStartPos; //File Snippet Start Position ZR=i*y  
long nEndPos; //File Snippet End Position @mu{*. &  
int nThreadID; //Thread's ID z"z$.c  
boolean bDownOver = false; //Downing is over =ePwGm1:c  
boolean bStop = false; //Stop identical 5FB3w48  
FileAccessI fileAccessI = null; //File Access interface yMkR)HY  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Rq2bj_j  
{ h*<`ct xL  
this.sURL = sURL; ^FNju/b  
this.nStartPos = nStart; yRQ1Szbjli  
this.nEndPos = nEnd; Y cL((6A  
nThreadID = id; Z;+;_Cw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 LdiNXyyzet  
}  nXy"  
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public void run() &'PLOyWw  
{ e)-$#qW  
while(nStartPos < nEndPos && !bStop) [-W~o.`  
{ hB>FJZQ_  
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try{ O['[_1n_u]  
URL url = new URL(sURL); *b{Hj'HaH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /'VuMMJ2  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1bw$$QXC_  
String sProperty = "bytes="+nStartPos+"-"; ODpAMt"  
httpConnection.setRequestProperty("RANGE",sProperty); {='wGx  
Utility.log(sProperty); n]w%bKc-9  
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InputStream input = httpConnection.getInputStream(); `;R$Ji=>  
//logResponseHead(httpConnection); ]{|l4e4P  
w0=/V[fs  
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byte[] b = new byte[1024]; g=v'[JPd  
int nRead; ]I/* J^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u@Ni *)p`  
{ ZV5IZ&V!  
nStartPos += fileAccessI.write(b,0,nRead); c*
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//if(nThreadID == 1) ESIeZhXVH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); sy(bL_%  
} `\ nKPj  
&432/=QSm0  
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Utility.log("Thread " + nThreadID + " is over!"); O]="ggq&  
bDownOver = true; =NK'xPr  
//nPos = fileAccessI.write (b,0,nRead); &jnBDr  
} P()&?C  
catch(Exception e){e.printStackTrace ();} rnMi >?  
} n sN n>{  
} a|d
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//打印回应的头信息 Q0ezeo  
public void logResponseHead(HttpURLConnection con) h^WMv *2  
{ ]w-W  
for(int i=1;;i++) +-V4:@  
{ mMu+MXTk<  
String header=con.getHeaderFieldKey(i); IK4(r /  
if(header!=null) F2n4#b  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t >64^nS  
Utility.log(header+" : "+con.getHeaderField(header)); .[:WMCc\  
else nhm#_3!6A  
break; XTb.cqOC  
} (YPG4:[  
} 4w 7vgB  
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public void splitterStop() V+|$H h8  
{ ]P^3uXi  
bStop = true; 9CIQRc  
} Vd) %qw  
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} axXR
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/* kMa|V0  
**FileAccess.java ^}z:FI   
*//文件访问(定位，写) /Vv)00  
package NetFox; MpJ3*$Dr  
import java.io.*; 0@&;JMh6<  
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public class FileAccessI implements Serializable{ ph~#{B(\  
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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 M|.ykA<D  
RandomAccessFile oSavedFile; %~Ymb&ugg  
long nPos; Cq\{\!6[  
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public FileAccessI() throws IOException Bq
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{ ufA0H J)Yg  
this("",0); m&_!*3BAG  
} aMgg[g9>t  
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public FileAccessI(String sName,long nPos) throws IOException 6k1_dRu  
{ .MxMBrM  
oSavedFile = new RandomAccessFile(sName,"rw"); (Y?}'?  
this.nPos = nPos; p,)pz_M  
oSavedFile.seek(nPos); U}-hV@y  
} cyI:dvg  
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public synchronized int write(byte[] b,int nStart,int nLen) TfNm0=|
 
{ 3"6-X_  
int n = -1; lI[O!VuKc  
try{ #W L>ha v  
oSavedFile.write(b,nStart,nLen); H)+wkR!~  
n = nLen; lIatM@gU  
} 7<F{a"5P  
catch(IOException e) E{B40E~4  
{ oJ0 #U  
e.printStackTrace (); wH qbTA  
} zh
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return n; l]P3oB}Yo  
} RLF]Wa,  
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} x#tP)5n?s*  
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/* !*B1Eo--cN  
**SiteInfoBean.java ]1KF3$n0  
*/ 4--[.j*W  
package NetFox; -;[,`g(f  
{(`xA,El  
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public class SiteInfoBean { +dK;\wT  
VQ`a-DL  
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private String sSiteURL; //Site's URL d-$/C| J  
private String sFilePath; //Saved File's Path JwmH_nJ(  
private String sFileName; //Saved File's Name 4kf8Am(  
private int nSplitter; //Count of Splited Downloading File \&X*-T[]j  
E#+|.0*!s  
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public SiteInfoBean() G(7WUMjl  
{//nSplitter的缺省值为5 HY'-P&H5(  
//default value of nSplitter is 5 q*K.e5"
'  
this("","","",5); o[K,(  
} |1"n\4$  
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+# tmsv]2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Q2!vO4!<N  
{ A{QA0X!p  
sSiteURL= sURL; gLPgh
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sFilePath = sPath; s4{>7`N2  
sFileName = sName; +,ojlTVlt  
this.nSplitter = nSpiltter; R9lb<`  
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%$SO9PY  
} [NIaWI,>
 
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public String getSSiteURL() y8=H+Y  
{ XSz)$9~hk  
return sSiteURL; yj C@  
} K)r|oW=6Y  
"iTi+UZxe  
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public void setSSiteURL(String value) 4z>SI\Ss  
{ 924a1
 
sSiteURL = value; H)O I&?  
} yMbg1+:   
;*XH[>I  
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public String getSFilePath() O4fl$egQU  
{ %.VFj7J  
return sFilePath; T:(c/>  
} 'Q F@@48  
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public void setSFilePath(String value) j?y_ H[Z  
{ HH9
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sFilePath = value; 80;^]l   
} lcYjwA  
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x 2Cp{+}  
public String getSFileName() &+zS4)UK  
{ &)v}oHy,m  
return sFileName; Sn!5/9Y  
} |KLCO'x  
2h5L#\H"  
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public void setSFileName(String value) e.jbFSnA  
{ V+&C_PyC  
sFileName = value; ~V6wcXd  
} n(tx'&U"R  
L:E?tR}H  
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](  
public int getNSplitter() FA3YiX(-e  
{ !omf>CW;ud  
return nSplitter; 0JM`*f%n  
} H$={i$*,Y  
M"
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];8S<KiS~  
public void setNSplitter(int nCount) 5>u,Qh  
{ )7s(]~z  
nSplitter = nCount; U/l3C(bc!  
} sw$$I~21  
} 5VR=D\j  
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/* '$\O*e'  
**Utility.java Vx*O^cM  
*/ GP{$w_'!J0  
package NetFox; @m+2e C77  
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B EB[K2[9  
public class Utility { !)$e+o^W  
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public Utility() ft><Ql3  
{ f )Ef
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} AMf{E  
mfCp@1;26  
//线程睡眠 G3_HX<|f*  
public static void sleep(int nSecond) qbD>)}:1  
{ ykat0iqo  
try{ ;Qq<5I"y  
Thread.sleep(nSecond); ,,HoD~]rd  
} &-zW1wf  
catch(Exception e) L| K8  
{ zW9/[Db  
e.printStackTrace (); 7w51UmO  
} P}8cSX9  
} R;3nL[{U  
^bG91"0A  
//日志 !@3"vd{^  
public static void log(String sMsg) _`.Wib+  
{ Ev>P|kV&A  
System.err.println(sMsg); @ q:S]YB  
} <`'T#e$  
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,  
^
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public static void log(int sMsg) u%sfHGrH  
{ h
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System.err.println(sMsg); (bp
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} |e{ ^Yf4  
} 7tQ?av  
8@A}.:  
,4--3 MU  
/* GW,RE\Q:  
**TestMethod.java <\`qRz0/  
*/ F_-}GN%  
package NetFox; Xb2.t^ ]f  
7.FD16  
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public class TestMethod { tE WolO[\  
7A"v:e  
z9Nial`p  
public TestMethod() #Oi{7~  
{ ///xx/weblogic60b2_win.exe w8}jmpnI  
try{ )m_q2xV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Z;~7L*|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); S\L^ZH?[2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); zmhL[1qj  
fileFetch.start(); zS*vKyye>  
} #Q` TH<  
catch(Exception e){e.printStackTrace ();} +vt?3i\^.  
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i F \H  
} `z$=J"%? y  
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public static void main(String[] args) %f5c,}  
{ @Y !Jm  
new TestMethod(); ek1<9"y  
} Q6;bORN  
} =$SvKzN  
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