http断点续传简单实现（java)

/* IZ@M K  
**SiteFileFetch.java .xe+cK  
*/ o`.5NUn  
package NetFox; %$F_oO7"  
import java.io.*; X<d`!,bn@  
import java.net.*; [0H]L{yV  
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public class SiteFileFetch extends Thread { !H(V%B
%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean WQv`%%G2>  
long[] nStartPos; //开始位置 `.F3&pA  
long[] nEndPos; //结束位置 Muok">#3.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [fg-"-+:M  
long nFileLength; //文件长度 T^S$|d  
boolean bFirst = true; //是否第一次取文件 -*;JUSGh  
boolean bStop = false; //停止标志 5}:`CC2,S~  
File tmpFile; //文件下载的临时信息 Qb@i_SX(fs  
DataOutputStream output; //输出到文件的输出流 ^4=%~Yx  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9:7&`JlC#  
public SiteFileFetch(SiteInfoBean bean) throws IOException d_ji ..T  
{ oG=4&SQ  
siteInfoBean = bean; T&->xef=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yK0iW  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); i'z(`"  
if(tmpFile.exists ()) uHPd!#]  
{ u2cDSRrqT  
bFirst = false; Ub`vf4EB  
read_nPos(); w~>tpkUB  
} c"pu"t@/Z  
else gb/<(I )  
{ _*n 4W^8  
nStartPos = new long[bean.getNSplitter()]; k; n
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nEndPos = new long[bean.getNSplitter()]; }r|$\ms  
} `vD.5  
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} TH*}Ja^/  
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public void run() U<wM#l P|Z  
{ Sw`+4 4  
//获得文件长度 ;Mz7emt  
//分割文件 \`-a'u=S  
//实例FileSplitterFetch _z53r+A  
//启动FileSplitterFetch线程 j7b4wH\#  
//等待子线程返回 Xn%O .yM6  
try{ "X\6tl7a|  
if(bFirst) H4uHCkj  
{ fy={  
nFileLength = getFileSize(); 7,FhKTV1/  
if(nFileLength == -1) 9/dADJe0b  
{  e,T^
8_>  
System.err.println("File Length is not known!"); qD{~QHDa  
} _c,{}sn  
else if(nFileLength == -2) wpcqgc  
{ QZFH>,d  
System.err.println("File is not access!"); 4}Yn!
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} I[bWd{i:  
else ]p8<Vluv  
{ zG\:#,9  
for(int i=0;i<nStartPos.length;i++) D/puK  
{ ,&s%^I+CC  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -(9TM*)O  
} 7|(o=+Bt  
for(int i=0;i<nEndPos.length-1;i++) fzzk#jU  
{ 13f'zx(AO  
nEndPos = nStartPos[i+1]; Uac.8wQh  
} ?4#wVzuzA  
nEndPos[nEndPos.length-1] = nFileLength; 9)D9'/{L#  
} tfVlIY<  
} UP*5M  
?P(U/DS8  
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//启动子线程 8Od7e`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; U;LX"'}  
for(int i=0;i<nStartPos.length;i++) bd)Sb?  
{ FA1h!Vit  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9ZI^R/*Kc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), EKNmXt1 lE  
nStartPos,nEndPos,i); N[;R8SP  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6\xfoy|j  
fileSplitterFetch.start(); S.!K  
} jz,Gj}3;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zh9B8r)C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~{l @
  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [I78<IJc  
nEndPos = " + nFileLength); $.3J1DU  
// fileSplitterFetch[nPos.length-1].start(); x57O.WdN  
R6\|:mI,$  
rAA?{(!9x  
//等待子线程结束 X-`PF  
//int count = 0; smHQ'4x9  
//是否结束while循环 1Sd<cOEd  
boolean breakWhile = false; pI( H7 (  
- @tL]]  
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while(!bStop) +<fT\Oq#  
{
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write_nPos(); 15R:m:T  
Utility.sleep(500); [FeN(8hGS  
breakWhile = true; *|6*jU  
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for(int i=0;i<nStartPos.length;i++) R/l/GNm  
{ #BX}j&h_  
if(!fileSplitterFetch.bDownOver) *.!5327  
{ B* k|NZj  
breakWhile = false; $'COsiK7  
break; R{q<V uN  
} wQojmmQ  
} (/A 6kp?  
if(breakWhile) `_(N(dm  
break; hHyB;(3~  
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Dp^6|T*HU  
//count++; "s7}eWM*a  
//if(count>4) wexa\o  
// siteStop(); LknV47vd  
} eOJ_L]y-  
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System.err.println("文件下载结束！"); <"nF`'olV  
} (>`S{L C>s  
catch(Exception e){e.printStackTrace ();} ]s`cn}d  
} LXm@h  
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)u
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//获得文件长度 #=#bv`  
public long getFileSize() 60r0O5=|Fl  
{ `Db%:l^e  
int nFileLength = -1; 8" (j_~;  
try{ Wx8n)  
URL url = new URL(siteInfoBean.getSSiteURL()); ]Ryg}DOQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n1rJ^q-G  
httpConnection.setRequestProperty("User-Agent","NetFox"); U[6 ~ad a  
D{M&>.  
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int responseCode=httpConnection.getResponseCode(); IY}{1[<N  
if(responseCode>=400) _vUId?9@+e  
{ #-kx$(''V  
processErrorCode(responseCode); @[~j|YH}  
return -2; //-2 represent access is error >[4CQK`U  
} nk2H^RM^  
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String sHeader; QPKY9.Rvv  
*OHaqe(*  
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for(int i=1;;i++) ogG:Ai)90  
{ 4\m#:fj %  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bP7_QYQ6  
//Utility.log(in.readLine()); " l>tFa  
sHeader=httpConnection.getHeaderFieldKey(i); |]]Rp  
if(sHeader!=null) 6{H@VF<QY!  
{ MsP`w3b
 
if(sHeader.equals("Content-Length")) S&MF; E6  
{ ?F9c6$|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Z=^~]Mfa  
break; r(I&`kF<  
} b;"Z`/h  
} wa
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else Sb?HRoe_  
break; AP0z~
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} X9o6} %Y  
} ij02J`w:Ra  
catch(IOException e){e.printStackTrace ();} (~]0)J  
catch(Exception e){e.printStackTrace ();} `9Q O'^)  
~Q+J1S]Fs  
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Utility.log(nFileLength); "(vm0@8><  
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return nFileLength; .`/6[Zp

 
} c='uyx  
'(SqHP|8&g  
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//保存下载信息（文件指针位置） "T~A*a^  
private void write_nPos() 2(2
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{ ABU~V+'2  
try{ =[YjIWr#o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /8LTM|(  
output.writeInt(nStartPos.length); SFVqUg3"Z  
for(int i=0;i<nStartPos.length;i++) E$s?)  
{ ,XsBm+Q(  
// output.writeLong(nPos); ]".SW5b_  
output.writeLong(fileSplitterFetch.nStartPos); 7?qR
z  
output.writeLong(fileSplitterFetch.nEndPos); sYd)r%%AU  
} d1u6*&@lf  
output.close(); 7xCm"jgP  
} y
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catch(IOException e){e.printStackTrace ();} 5
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catch(Exception e){e.printStackTrace ();} IV|})[n*  
} c:`CL<xzU  
@^,9O92l  
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//读取保存的下载信息（文件指针位置） MmD1@fW32#  
private void read_nPos() rl:D>t(:.  
{ eI=:z/p
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try{ R|-!5J4h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \
6 :7  
int nCount = input.readInt(); JO&+W^$uY}  
nStartPos = new long[nCount]; ;f9a0Vs  
nEndPos = new long[nCount]; )\QPUdOvx  
for(int i=0;i<nStartPos.length;i++) 5k`Df/  
{ [*d<LAnuWP  
nStartPos = input.readLong(); P5o

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nEndPos = input.readLong(); ?pkGejcQ  
} xQ>T.nP}1  
input.close(); XWBTBL  
} 4[ =C,5r  
catch(IOException e){e.printStackTrace ();} ^%}PRl9  
catch(Exception e){e.printStackTrace ();} G(MLq"R6U  
} I0}G, q  
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private void processErrorCode(int nErrorCode) xGt>X77  
{ 8RU91H8fE  
System.err.println("Error Code : " + nErrorCode); 7>xfQ  
} }/M`G]wT#  
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lh*!f$2~  
//停止文件下载 "1ov<  
public void siteStop() c>L#(D\\  
{ ^d!I{ y#  
bStop = true; l#rr--];  
for(int i=0;i<nStartPos.length;i++) Fqg*H1I[  
fileSplitterFetch.splitterStop(); (?#"S67  
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} {i/7Nx
 
} tJ Mm  
//负责部分文件的抓取 /e]R0NI  
**FileSplitterFetch.java :p.f zL6X  
*/ .pPtBqp  
package NetFox; c!J|vRA5  
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import java.io.*; k5eTfaxl  
import java.net.*; -5<G^AS  
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public class FileSplitterFetch extends Thread { RwDXOdg
u  
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String sURL; //File URL c->?'h23)  
long nStartPos; //File Snippet Start Position M`Q
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long nEndPos; //File Snippet End Position Y&1Yc)*O  
int nThreadID; //Thread's ID p9j2jb,qy  
boolean bDownOver = false; //Downing is over lfyij[6q+  
boolean bStop = false; //Stop identical k;pU8y6Y  
FileAccessI fileAccessI = null; //File Access interface !c=EB`<*  
0oo*F  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vze|*dKS  
{ qWb8"  
this.sURL = sURL; {|R +|ow  
this.nStartPos = nStart; la89>pF  
this.nEndPos = nEnd; h3z9}'  
nThreadID = id; *M+CA_I(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :[bpMP<bz;  
}
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public void run() 'Ad|*
~  
{ r,cK#!<%  
while(nStartPos < nEndPos && !bStop) [
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{ XA
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try{ |k=5`WG  
URL url = new URL(sURL); Lr<?eWdCwJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); okLheF  
httpConnection.setRequestProperty("User-Agent","NetFox"); 89a`WV@}  
String sProperty = "bytes="+nStartPos+"-"; ,<<HkEMS  
httpConnection.setRequestProperty("RANGE",sProperty); &|c] U/_w  
Utility.log(sProperty); RbJbVFz8C  
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9~yp=JOV@  
InputStream input = httpConnection.getInputStream(); a\Dw*h?b~  
//logResponseHead(httpConnection); 0m'tPFQ|  
^LAdN8Cbb  
4/E>k <MA  
byte[] b = new byte[1024]; -k}&{v  
int nRead; -SKcS#IF  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -|`
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{ f4&k48Ds  
nStartPos += fileAccessI.write(b,0,nRead); },vVc/  
//if(nThreadID == 1) P*9L3R*=N  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #4ii!ev  
} QS2~}{v  
x*0mmlCb  
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Utility.log("Thread " + nThreadID + " is over!"); +V/mV7FK  
bDownOver = true; }
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//nPos = fileAccessI.write (b,0,nRead); 'kk B>g7B  
} jjJ l\Vn  
catch(Exception e){e.printStackTrace ();} SAGECK[Ix  
} f<P>IE  
} $iOkn|~<@W  
0
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VMV~K7%0  
//打印回应的头信息 >@L^^-r  
public void logResponseHead(HttpURLConnection con) z|sR `
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{ Fn*)!,)  
for(int i=1;;i++) PZSi}j/  
{ 5vjtF4}7!  
String header=con.getHeaderFieldKey(i); xZp`Ke
!  
if(header!=null) 7G9o%!D5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D8wZC'7  
Utility.log(header+" : "+con.getHeaderField(header)); I>45xVA  
else q?Av5TFf  
break; i-31Cxb  
} 8ubb~B;  
} :qO)^~x  
=.f<"P51k  
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public void splitterStop() h}<Ie <  
{ 'EsdYx5C  
bStop = true; +u'y!@VV  
} oSB0P  
#;Z+X)  
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}
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/* L*Q#!_K0P  
**FileAccess.java * 2s(TW  
*//文件访问(定位，写) 0vi\o`**Mj  
package NetFox; L$s;tJ   
import java.io.*; h|Udw3N1L  
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xgv&M:%D-  
public class FileAccessI implements Serializable{ GXx/pBdy[4  
iJ 8I# j+N  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3hbUus  
RandomAccessFile oSavedFile; /2AeJH\-  
long nPos; Q>[GD(8k  
Z<n%~z^  
<%Afa#  
public FileAccessI() throws IOException y|[YEY U)  
{ Y#aHGZ$i  
this("",0); YztW1GvI  
} E
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L$<(HQQJ8  
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public FileAccessI(String sName,long nPos) throws IOException a]8}zSUK  
{ ck\gazo~q  
oSavedFile = new RandomAccessFile(sName,"rw"); Yeb-u+23  
this.nPos = nPos; 0@*EwI  
oSavedFile.seek(nPos); 8f{;oO  
} \' ;zD-MX  
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0I \l_St@  
public synchronized int write(byte[] b,int nStart,int nLen) jbK<"T5  
{ o5|P5h  
int n = -1; !'T,%8']  
try{ ECEDNib  
oSavedFile.write(b,nStart,nLen); u[2B0a  
n = nLen; 
`#w`-  
} 3# r`e  
catch(IOException e) R=u!RcvR  
{ <zE~N~;  
e.printStackTrace (); qLh[BR  
} (L7@ez  
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return n; ,I|TjC5  
} YsXf+_._  
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} %44Z7  
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/* 0-a[[hL?  
**SiteInfoBean.java 3a\.s9A"  
*/ zQhc V  
package NetFox; q&N1| f7  
Q]oCzSi  
e#jkp'  
public class SiteInfoBean { FfR%@ V'  
C.}Vm};M  
}|!9aojr  
private String sSiteURL; //Site's URL /~B\1  
private String sFilePath; //Saved File's Path #+]-}v3  
private String sFileName; //Saved File's Name 9#A&Qvyywg  
private int nSplitter; //Count of Splited Downloading File 4x%R4tk  
Z>+Tzvfud  
ra*(.<&  
public SiteInfoBean() TScI_8c>  
{//nSplitter的缺省值为5 :ncR7:Z  
//default value of nSplitter is 5  y+.E}  
this("","","",5); yJ!x`RD),w  
} 1ZK~i  
BPkqC>w  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Xs7xZ$  
{ l9up?opq  
sSiteURL= sURL; FY6!)/P0I7  
sFilePath = sPath; >s+TD4OfY  
sFileName = sName; 1}"PLq(  
this.nSplitter = nSpiltter; x%\m/_5w%  
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:VEy\ R>W  
} ]&l%L4Z  
`zZGL&9m`  
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public String getSSiteURL() 5? rR'0  
{ 3"XS#~l%  
return sSiteURL; ",&c"r4c  
} g=)djXW  
]fgYO+  
6*92I  
public void setSSiteURL(String value) ka$oUB)iQ  
{ "Yu';&  
sSiteURL = value; +zup+=0e  
} '7Aj0U(  
31@m36? X  
uY~xHV_-  
public String getSFilePath() v%%;Cp73  
{ XdR^,;pWE  
return sFilePath; _x ;fTW0  
} )5(Ko<"  
9q=\_[\[  
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public void setSFilePath(String value) D^%DYp  
{ P)$q  
sFilePath = value; y$n`+%_  
} 7Odw{pc  
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public String getSFileName() }1/`<m  
{ ,9:0T LLR  
return sFileName; `p.O  
} k}o*=s>M  
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z]Jpvw`p  
public void setSFileName(String value) #*|0WaC  
{ KW~fW r8  
sFileName = value; vKvT7Zxc  
} /EpsJb`kj  
4}\Dr %US  
zwyK \j  
public int getNSplitter() B- VhUS  
{ %bs~%6)  
return nSplitter; gqi|k6V/  
} MSMgaw?  
[sT}hYh+  
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public void setNSplitter(int nCount) ?H.7 WtTC  
{ [$D4U@mRp  
nSplitter = nCount; mCY+V~^~kz  
} l"-F<^ U  
} %?7j Q  
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XZk?aik}`  
/* jPjFp35;zb  
**Utility.java N){/#3  
*/ bz=B&YR  
package NetFox; 8+irul{H_  
6_w;dnVA  
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public class Utility { q["T6  
 ~/B[;#  
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public Utility() u=5~^ 9  
{ 4X5Tyv(Dp  
EZ.|6oug\  
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} 3]X~bQAw  
?oc#$fcQ~  
//线程睡眠 t*&O*T+fgy  
public static void sleep(int nSecond) =[$zR>o*%  
{ *:*Kdt`'G  
try{ o y'GAc/  
Thread.sleep(nSecond); pd[?TyVK;  
} kdX]Afyj  
catch(Exception e) {I2qnTN_a  
{ 6IVa(;  
e.printStackTrace (); ;3D[[
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} ,/qS1W(  
} 
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//日志 Xyrf$R'  
public static void log(String sMsg) ^,$>z*WQ.  
{ 7|"gMw/  
System.err.println(sMsg);  Psf'#4g  
} *)2&gQ&%+  
2J
V,AZf  
6S~lgH:  
public static void log(int sMsg) U#jbii6e  
{ d`_X$P4y  
System.err.println(sMsg); wjr1?c  
} ]y3'6!
 
} 6uU2+I  
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m),3J4(q  
/* B@Ae2_;  
**TestMethod.java m 8Q[+_:$H  
*/ YXR%{GUP[  
package NetFox; j^g^=uau  
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YB}p`b42L  
public class TestMethod { ]Y%?kQ^  
6n 2LG  
DKjkO5R\  
public TestMethod() \>@'wl  
{ ///xx/weblogic60b2_win.exe Z?vbe}pUM  
try{ U(.3[x  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @"6dq;"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); hY?x14m$3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %U.aRSf/  
fileFetch.start(); \eD{bD  
} oWZbfR9R  
catch(Exception e){e.printStackTrace ();} BtyBZ8P;e  
gU
oL8~  
5df~] -=0Y  
} J&xH"U  
B/(]AWi+  
M``I5r*cg  
public static void main(String[] args) eQ}o;vJN  
{ Btmv{'T_y@  
new TestMethod(); W6&s_ (  
} DL^}?Ve  
} 6o
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