http断点续传简单实现（java)

/* <lIm==U<-  
**SiteFileFetch.java uoE+:,P  
*/ fTPm Fb  
package NetFox; >Z_;ZMu)  
import java.io.*; Sdmz(R  
import java.net.*; PjBAf'  
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public class SiteFileFetch extends Thread { V~KWy@7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean r&a}U6k(y  
long[] nStartPos; //开始位置 Wfd`v  
long[] nEndPos; //结束位置 MF'Z?M  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 yOEy3d=*  
long nFileLength; //文件长度 #N`G2}1J  
boolean bFirst = true; //是否第一次取文件 `mteU"{bx  
boolean bStop = false; //停止标志 +ho=0>  
File tmpFile; //文件下载的临时信息 auAz>6L  
DataOutputStream output; //输出到文件的输出流 k;cX,*DIn  
2#
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _J,rql@nG<  
public SiteFileFetch(SiteInfoBean bean) throws IOException .qohHJ&  
{ na $MR3@e  
siteInfoBean = bean; cSYCMQ1ro  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2_u+&7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z ;rM@x  
if(tmpFile.exists ()) %XukiA+  
{ }(u:K}8  
bFirst = false; KPz0;2}  
read_nPos(); BZ.l[LMp  
} e.MyJ:eL  
else eC<RM Q4  
{ JjI1^FRd  
nStartPos = new long[bean.getNSplitter()]; [6RODp3')  
nEndPos = new long[bean.getNSplitter()]; Sw E7U~  
} AP>n-Z|  
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} R- >~MLeK]  
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public void run() \e4AxLP  
{ Ng;?hTw  
//获得文件长度 6XA(<1P  
//分割文件 =gSc{ i|  
//实例FileSplitterFetch REU&8J@k&?  
//启动FileSplitterFetch线程 VOr:G85*s  
//等待子线程返回 >F7HKwg}Z  
try{ H%l-@::+$  
if(bFirst) C;:=r:bth  
{ (=u!E+
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nFileLength = getFileSize(); bnkZWw'9  
if(nFileLength == -1) QlB9m2XB  
{ )=gU~UV  
System.err.println("File Length is not known!"); nU{Qi;0  
} ?0dmw?i  
else if(nFileLength == -2) 4"eFR'g  
{ /PSXuVtu5  
System.err.println("File is not access!"); L7<30"7  
} `-U?{U}H  
else LyvR].p=5*  
{ j<!dpt  
for(int i=0;i<nStartPos.length;i++) >G!=lLyR  
{ HP*{1Q@5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *A48shfO  
} AEj%8jh  
for(int i=0;i<nEndPos.length-1;i++) RrBG=V  
{ 5!'1;GLs  
nEndPos = nStartPos[i+1]; :D3:`P>,c  
}  1h
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nEndPos[nEndPos.length-1] = nFileLength; 93.\.&L\  
} -32P}58R  
} '")'h  
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6FUcg40Y  
//启动子线程 p8j4Tc5tQ>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I__b$  
for(int i=0;i<nStartPos.length;i++) TT(R<hL  
{ PJm@fK(j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 40 u tmC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _(m455HZ  
nStartPos,nEndPos,i); a3M
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *iru>F8r:  
fileSplitterFetch.start(); yR{rje*  
} ))dqC l  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *"_W1}^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pLF,rOb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'W9[Vm  
nEndPos = " + nFileLength); qF(i1#  
// fileSplitterFetch[nPos.length-1].start(); sd+_NtH  
=pmG.>Si  
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//等待子线程结束 g*FHZM*N9  
//int count = 0; QPp31o.!5  
//是否结束while循环 ~eP~c"L  
boolean breakWhile = false; JP"#9f  
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while(!bStop) b-VQn5W  
{ Q~f]?a`  
write_nPos(); @b 17jmq{  
Utility.sleep(500); p)Q5fh0-  
breakWhile = true; )Z4iM;4]  
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for(int i=0;i<nStartPos.length;i++) &.2
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{ 5G'2 Wby'#  
if(!fileSplitterFetch.bDownOver) a(fiW%eFb  
{ }+`,AC`RM  
breakWhile = false; Q: -&
  
break; njJTEUd">  
} 7Cz=;  
} R(_WTs9x4  
if(breakWhile) !a V:T&6  
break; )!VJ\  
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//count++; @Kt!uKrI  
//if(count>4) daA&!vnbH*  
// siteStop(); r&v!2A]:  
} {_4Hsw?s6  
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OUN~7]OD%  
System.err.println("文件下载结束！"); ~3Qa-s;g  
} JY:Fu  
catch(Exception e){e.printStackTrace ();} 1bw$$QXC_  
} kAUL7_>6X  
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//获得文件长度 32j#kJW  
public long getFileSize() 9ec#'i=  
{ 753gcY#i  
int nFileLength = -1; ey<z#Q5+  
try{ aRn""3[  
URL url = new URL(siteInfoBean.getSSiteURL()); fCs{%-6cP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $b^niL  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]I/* J^  
96!2@c{  
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int responseCode=httpConnection.getResponseCode(); {<Y!'WL{  
if(responseCode>=400) 
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{
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processErrorCode(responseCode); h;(mb2[R  
return -2; //-2 represent access is error lt5Knz2G,Z  
} (?T{^Hg  
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String sHeader; . Z9c.E{  
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for(int i=1;;i++) 1"<{_&d1  
{ meap;p  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); pK>/c>de  
//Utility.log(in.readLine()); ~S :8M<aB  
sHeader=httpConnection.getHeaderFieldKey(i); NN:zQ_RT  
if(sHeader!=null) 2=7[r-*E  
{ :c}PW"0v  
if(sHeader.equals("Content-Length")) VJr~h "[  
{ wB[ JFy"E  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mH<|.7~0  
break; Bbb":c6w0  
} :$X dR:f}}  
} Kp;<z<  
else NDe FY  
break; nhm#_3!6A  
} XTb.cqOC  
} >)>~S_u  
catch(IOException e){e.printStackTrace ();} a9 S&n5  
catch(Exception e){e.printStackTrace ();} TEK#AR  
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Utility.log(nFileLength); 7D8 pb0`;J  
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return nFileLength; oq>jCOVh  
} :Xx7':5  
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%N7G>_+  
//保存下载信息（文件指针位置） \D%n8O  
private void write_nPos() OMjx,@9  
{ PUd/|Rc/}  
try{ u VUrg;>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0o.h{BN  
output.writeInt(nStartPos.length); xTZJ5iZ17  
for(int i=0;i<nStartPos.length;i++) 3)^2X  
{ zJ8jJFL+Y  
// output.writeLong(nPos); S~g"  
output.writeLong(fileSplitterFetch.nStartPos); PIsXX#`7;  
output.writeLong(fileSplitterFetch.nEndPos); 6UPGE",u  
} Kt"4<'  
output.close(); 94rx4"AN8;  
} N45@)s!F9j  
catch(IOException e){e.printStackTrace ();} P^BSl7cT  
catch(Exception e){e.printStackTrace ();} 3[kl` *`  
} ZGd7e.u=  
; ?,'jI*1  
rO,n~|YJ  
//读取保存的下载信息（文件指针位置） ]7|qhAh<L  
private void read_nPos() X5Y. o&  
{ *unJd"<*&@  
try{ _z"\3hZ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Z= pvoTY  
int nCount = input.readInt(); 6k1_dRu  
nStartPos = new long[nCount]; $yFR{_]  
nEndPos = new long[nCount]; w-wJhc|  
for(int i=0;i<nStartPos.length;i++) (Y?}'?  
{ w/fiNY5FZ  
nStartPos = input.readLong(); LA,G>#?H  
nEndPos = input.readLong(); U}-hV@y  
} eoiC.$~\  
input.close(); DK%@[D  
} bde6 ;=oM  
catch(IOException e){e.printStackTrace ();} -K5u5l}  
catch(Exception e){e.printStackTrace ();} m?1AgsBR  
} s*kSl:T@O  
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private void processErrorCode(int nErrorCode) Q(hAV  
{ ~?lmkfy  
System.err.println("Error Code : " + nErrorCode); OZl0I#@A  
} x Sv@K5"8!  
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=vKSvQP@)  
//停止文件下载 ?d)eri8,  
public void siteStop() YQ}IE[J}v  
{ c/G^}d%  
bStop = true; 0t00X/  
for(int i=0;i<nStartPos.length;i++) .YIb ny1  
fileSplitterFetch.splitterStop(); -s:NF;"  
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} &<5oDdC  
} =I)Ex)  
//负责部分文件的抓取 wpJfP_H  
**FileSplitterFetch.java N..@}}  
*/ _8?r!D#P;s  
package NetFox; f{R/rb&iB  
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import java.io.*; u|&a!tOf2  
import java.net.*; !2=e
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public class FileSplitterFetch extends Thread { g _u  
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String sURL; //File URL R<8!lQ4s  
long nStartPos; //File Snippet Start Position OQsF$%*  
long nEndPos; //File Snippet End Position >Co5_sCe  
int nThreadID; //Thread's ID ;e^`r;]  
boolean bDownOver = false; //Downing is over iD!]I$  
boolean bStop = false; //Stop identical 2-u9%  
FileAccessI fileAccessI = null; //File Access interface f(*^zga,  
)}R w@70L-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nOUF<DNQ  
{ !\1Pu|  
this.sURL = sURL; O<qo%f
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this.nStartPos = nStart; 6y)NH 8l7  
this.nEndPos = nEnd; 5!d'RBO   
nThreadID = id; oOy_2fwZPp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 j}@n`[V1  
} ns !Mqcm  
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public void run() l=t$XWh!  
{ q{oppali  
while(nStartPos < nEndPos && !bStop) \MFjb IL  
{ {vAv ;m  
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try{ g%f6D%d)A  
URL url = new URL(sURL); ioS(;2F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); RE75TqYW  
httpConnection.setRequestProperty("User-Agent","NetFox"); r4Jc9Tvd  
String sProperty = "bytes="+nStartPos+"-"; Y**|e4  
httpConnection.setRequestProperty("RANGE",sProperty); zvnR'\A_  
Utility.log(sProperty); y8=H+Y  
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InputStream input = httpConnection.getInputStream(); "94qBGf  
//logResponseHead(httpConnection); %13V@'e9  
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byte[] b = new byte[1024]; @t?uhT*Z=  
int nRead; O0,=@nw8.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 
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{ I Z{DR  
nStartPos += fileAccessI.write(b,0,nRead); l^E)XWd  
//if(nThreadID == 1) GbN|!,X1m  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YB'BAX<lI  
} K';x2ffj  
:f5"w+  
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Utility.log("Thread " + nThreadID + " is over!"); "Z*u2_ H  
bDownOver = true; /p_#8
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//nPos = fileAccessI.write (b,0,nRead); jz72~+)T  
} ^26}j uQ  
catch(Exception e){e.printStackTrace ();} t bEJyA  
} H|*Ual  
} JP*VR=0k?  
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._
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//打印回应的头信息 /32x|Ow# 1  
public void logResponseHead(HttpURLConnection con) Z. G<
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{ wxSJ  
for(int i=1;;i++) e.jbFSnA  
{ \t^h|<`  
String header=con.getHeaderFieldKey(i); M|xs>+r*  
if(header!=null) 2Bg0 M  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y]6kA5  
Utility.log(header+" : "+con.getHeaderField(header)); eT6T@C
](  
else FA3YiX(-e  
break; !omf>CW;ud  
} 0JM`*f%n  
} H$={i$*,Y  
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public void splitterStop() 1'"TO5  
{ _[t:Vme}v  
bStop = true; 7@uhw">mX  
} ?,0 a#lG  
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} @U
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'$\O*e'  
/* {f:%+h  
**FileAccess.java WYXh1_nyk  
*//文件访问(定位，写) '|rhm  
package NetFox; ztb?4f q6)  
import java.io.*; ^'ac|+  
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* faG0le  
public class FileAccessI implements Serializable{ <Po$|$_~  
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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 c1aIZ  
RandomAccessFile oSavedFile; [h[@?8vB  
long nPos; e> -fI_+b  
h"$)[k~  
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public FileAccessI() throws IOException G3_HX<|f*  
{ ~D\zz }l  
this("",0); VBv|7S  
} oo2CF!Xy  
<<l1zEf@  
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public FileAccessI(String sName,long nPos) throws IOException >PmnR>x-rj  
{ S";c7s  
oSavedFile = new RandomAccessFile(sName,"rw"); 7X`]}z4g  
this.nPos = nPos; !THa?U;  
oSavedFile.seek(nPos); c%@< h6  
} Ssg1p#0J  
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public synchronized int write(byte[] b,int nStart,int nLen) }^tW's8  
{ B3g#)  
int n = -1; 8$`$24Wx  
try{ ~KP@wD~  
oSavedFile.write(b,nStart,nLen); vef9*u`  
n = nLen; {u)>W@Lr  
} _{&bmE  
catch(IOException e) L~|_CRw  
{ @<`P-+m  
e.printStackTrace (); #G!\MYfQt  
} DA_}pS"  
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/?Hq  
return n; {L/hhKT  
} F_-}GN%  
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} Tnoy#w}Ve  
7&&3@96<*#  
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/* AjD?_DPc  
**SiteInfoBean.java ,s`4k?y  
*/ 4@r76
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package NetFox; G3dA`3  
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public class SiteInfoBean { |'qvq/#^  
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private String sSiteURL; //Site's URL R
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private String sFilePath; //Saved File's Path YHzP/&0  
private String sFileName; //Saved File's Name U%)-_ *`z  
private int nSplitter; //Count of Splited Downloading File =*{Ii]D  
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1+9!
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public SiteInfoBean() ]FEDAGu
 
{//nSplitter的缺省值为5 Q8D#kAYw  
//default value of nSplitter is 5 oy\U\#k   
this("","","",5); .<4U2h  
} Qz4Do6#y  
T/234;Uf|  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) sB8v:
 
{ G@P+M1c  
sSiteURL= sURL; mJZB@m u?  
sFilePath = sPath; +CN!3(r  
sFileName = sName; ~9Qd83`UH  
this.nSplitter = nSpiltter; 4JRQ=T|P7I  
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} |7QSr!{_  
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public String getSSiteURL() \aN7[>R.Q  
{ *alifdp
 
return sSiteURL; {Z1KU8tp  
} {q! :t0X.Y  
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public void setSSiteURL(String value) u#UtPF7q  
{ .u
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sSiteURL = value; _rg*K  
} ?[;>1+D  
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public String getSFilePath() ^
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{ G > t  
return sFilePath; 1zgM
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} ;3XOk+  
6)c-s|#  
re4A5Ev$  
public void setSFilePath(String value) $18?Q+?3  
{ \5}*;O@  
sFilePath = value; _2hZGC%&E  
} @z^7*#vQv  
~G1B}c]  
~OWpk)Vq  
public String getSFileName() (8~D^N6Z  
{ a"l\_D'.K8  
return sFileName; yKy )%i  
} k"|Fu   
wI;sZJc  
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public void setSFileName(String value) WIabQ_fX  
{ D#A6s32a  
sFileName = value; TKQ^D  
} J9MAnYd)i  
Ym.{ {^=  
{eVv%sbq  
public int getNSplitter() `O5427Im  
{ -@ra~li,yQ  
return nSplitter; ^7a@?|,q8  
} Ckc5;:b&m  
yb,X }"Et  
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public void setNSplitter(int nCount)  !#zO%  
{ ~~=]_lwyK%  
nSplitter = nCount; eV~"T2!Sb  
} %CrTO(  
} P
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)7
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/* ^#IE t#  
**Utility.java Wt=\hixj-  
*/ |AT`(71  
package NetFox; K>C@oE[W  
0Y:)$h2?  
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public class Utility { =sAU5Ag68  
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:5BCW68le  
public Utility() fzA Fn$[  
{ iXq*EZb"R  
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rNurzag  
} mkhWbzD'S  
/='Q-`?9  
//线程睡眠 m'N8[ o|h  
public static void sleep(int nSecond) (#Xs\IEVF  
{ {> <1K6t  
try{ V%z?wDC  
Thread.sleep(nSecond); ens]?,`0  
} *
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catch(Exception e) y/:%S2za>  
{ d!4TwpIgx  
e.printStackTrace (); (z8;J>7  
} R7K`9 c1f6  
} I~^Xw7  
!XM<`H/  
//日志 uE
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public static void log(String sMsg)
^B%c3U$o  
{ g"k4Z  
System.err.println(sMsg); 2r;h">  
} ca3SE^  
q"6$#o{~U  
u!&T}i:  
public static void log(int sMsg) 5423Ky<
 
{ T?QW$cU!e:  
System.err.println(sMsg); CBF<53TshR  
} lSlZ^.&  
} QnP?j&  
G+Bk!o  
'2hy%  
/* 2g~ @99`  
**TestMethod.java em5~4;&'  
*/ Bs`{qmbC  
package NetFox; =mF"D:s*  
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public class TestMethod { &3;"$P  
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g4W/T  
public TestMethod() H(tC4'tA  
{ ///xx/weblogic60b2_win.exe D[?;+g/  
try{ !icI Rqcf=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .@%L8_sMR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); v|\#wrCT?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |cP:1CRzi  
fileFetch.start(); ~\i(bFd)  
} dvqg H  
catch(Exception e){e.printStackTrace ();} l2:-).7xt  
3;VH'hh_  
%p$XK(6  
} vd(S&&]o1  
_p5#`-%mM  
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public static void main(String[] args) I.G[|[. Do  
{ 4hLk+z<n  
new TestMethod(); }( CYok  
} ACi,$Uq6R  
} ~CbiKez  
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