http断点续传简单实现（java)

/* U- a+LS  
**SiteFileFetch.java 0Th
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*/ sX~ `Vn&  
package NetFox; '!%Zf;Fjr  
import java.io.*; hZobFf  
import java.net.*; %;r0,lN|II  
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public class SiteFileFetch extends Thread { ~j`;$o  
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SiteInfoBean siteInfoBean = null; //文件信息Bean dt -=7mz#  
long[] nStartPos; //开始位置 X. =%  
long[] nEndPos; //结束位置 &ZRriqsQg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 uP-I7l0i1  
long nFileLength; //文件长度 i@C1}o-/  
boolean bFirst = true; //是否第一次取文件 2)A% 'Akf  
boolean bStop = false; //停止标志 cBO.96ZHE  
File tmpFile; //文件下载的临时信息 VR@V3 ~  
DataOutputStream output; //输出到文件的输出流 &C.{7ZNt  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 02lI-xHe  
public SiteFileFetch(SiteInfoBean bean) throws IOException #]iSh(|8  
{ /7nircXj@  
siteInfoBean = bean; (Mk9##R#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )e$}sw{t  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ._uXK[c7P  
if(tmpFile.exists ()) =q%Q^  
{ KZ"&c~[  
bFirst = false; V5MLzW\8  
read_nPos(); }W:Rg}v  
} <@DF0x!  
else 1gA9h-'w  
{ ne=?'e4  
nStartPos = new long[bean.getNSplitter()]; DcO$&)Eb  
nEndPos = new long[bean.getNSplitter()]; w&vZ$n-|  
} f(^? PGO  
}, < dGmkx  
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} ScgaWJ  
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public void run() i;u#<y{E  
{ ig Q,ZY1  
//获得文件长度 XYi-o][Mf  
//分割文件 M@k8;_5  
//实例FileSplitterFetch \F$Vm'f_  
//启动FileSplitterFetch线程 e ej:  
//等待子线程返回 ;i)NP X  
try{ _(U|Kpi  
if(bFirst) 1Mftq4nq  
{ o =oXL2}  
nFileLength = getFileSize(); *{t]fds  
if(nFileLength == -1) -x~4@~  
{ pk%%}tP<  
System.err.println("File Length is not known!"); tJ"8"T#6Vr  
}
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else if(nFileLength == -2) \jkMnS6FvL  
{ p;y\%i_  
System.err.println("File is not access!"); _~l*p"PL<  
} ,2|(UTv  
else %4=
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{ ~t>i+{JKE  
for(int i=0;i<nStartPos.length;i++) AHo4% 5  
{ IL]Js W  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); K&Sz8# +  
} 0^0Q0A  
for(int i=0;i<nEndPos.length-1;i++) \>DMN #  
{ 0r=KY@D  
nEndPos = nStartPos[i+1]; n$*e(  
} wWI1%#__|o  
nEndPos[nEndPos.length-1] = nFileLength; 1edeV48{:  
} T{US
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} ^$!H|  
;kX:k~,]}>  
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//启动子线程 F['<;}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; pV^(8!+  
for(int i=0;i<nStartPos.length;i++) 6E
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{ <o aVI?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^$D2fS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Wx`|u  
nStartPos,nEndPos,i); CJ~gE"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f\|R<3 L  
fileSplitterFetch.start(); $`wo8A|)  
} ndXUR4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GyVRe]<>B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !eC]=PoY  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "!AbH<M;@  
nEndPos = " + nFileLength); 3G.-JLhs  
// fileSplitterFetch[nPos.length-1].start(); #cAX9LV  
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//等待子线程结束 A7hWAq  
//int count = 0; vJ a?5Jr  
//是否结束while循环 }#Q?\  
boolean breakWhile = false; ImG7E w  
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H!
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while(!bStop) ?O|CY
 
{ "%?$BoJR0  
write_nPos(); 3c|u2Pl  
Utility.sleep(500); s6YnNJ,SK  
breakWhile = true; dBG5IOD  
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for(int i=0;i<nStartPos.length;i++) +*')0I
 
{ B']}n`
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if(!fileSplitterFetch.bDownOver) )bkJ['9  
{ C"[d bh!  
breakWhile = false; U'Mxf'q  
break; {*NM~yQ  
} 6$ \69   
} C U 8s*  
if(breakWhile) +DR,&;  
break; S4!}7NOh  
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//count++; KM&bu='L^  
//if(count>4) 5@/hqOiu  
// siteStop(); DFvj  
} i[r>^U8O  
` &{  
|-zefzD|  
System.err.println("文件下载结束！"); 9_&N0>OF  
} Y3M"a8e'  
catch(Exception e){e.printStackTrace ();} L8.u7(-#  
} MWHzrqCA  
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//获得文件长度 AY)R2> fW%  
public long getFileSize() hG!|
ts  
{ yGZsPQIaV  
int nFileLength = -1; 
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try{ d:GAa   
URL url = new URL(siteInfoBean.getSSiteURL()); -D^.I
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b[;Zl<  
httpConnection.setRequestProperty("User-Agent","NetFox"); vIpitbFC  
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int responseCode=httpConnection.getResponseCode(); ;:4PT~\*  
if(responseCode>=400) yh{Wuz=T  
{ nZP%Z=p7  
processErrorCode(responseCode); Ew$-,KC[  
return -2; //-2 represent access is error FF'Ul4y  
} nX\Q{R2  
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String sHeader; p5?8E$VHV  
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for(int i=1;;i++) yIG*  
{ eczS(KoL4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); OdHl
)"#  
//Utility.log(in.readLine()); h6uv7n~4  
sHeader=httpConnection.getHeaderFieldKey(i); u
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if(sHeader!=null) |:G`f8
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{ O$$$1VHYo  
if(sHeader.equals("Content-Length")) YdiXj |k+  
{ l.AG^b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~RIn7/A  
break; le.(KgRS4  
} bP3S{Jt-|  
} Qe;j_ BH  
else g4CdzN~  
break; VSQxlAGk@  
} $bo 5:c  
} S)~Riuy$  
catch(IOException e){e.printStackTrace ();} uU#
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catch(Exception e){e.printStackTrace ();} ,.PW qfb  
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~ @Au<  
Utility.log(nFileLength); 9_5tA'Q  
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return nFileLength; m(c5g[6nO  
} ~n$e  
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//保存下载信息（文件指针位置） ?iQA>P9B  
private void write_nPos() +(9qAB7  
{ i~04P  
try{ }iF"&b0n"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); jhmWwT/O8^  
output.writeInt(nStartPos.length); #w<:H1,4
 
for(int i=0;i<nStartPos.length;i++) +ysP#uAA  
{ 5Zdxn>  
// output.writeLong(nPos); 3[E)/~-  
output.writeLong(fileSplitterFetch.nStartPos); {@gTs  
output.writeLong(fileSplitterFetch.nEndPos); KN"V(<!)~  
} 7 *#pv}Y  
output.close(); 8LouCv(>  
} C)Ez>~Z  
catch(IOException e){e.printStackTrace ();} m+Bt9|d  
catch(Exception e){e.printStackTrace ();} >kJEa8  
} )^o7%KX  
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//读取保存的下载信息（文件指针位置） 8`/nk`;  
private void read_nPos() 5$ra4+k0  
{ 7k>sE  
try{
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); utz!ElzA  
int nCount = input.readInt(); Zk.LGYz  
nStartPos = new long[nCount]; Jc:gNQCsP  
nEndPos = new long[nCount]; (|PxR#{l<  
for(int i=0;i<nStartPos.length;i++) Jm+hDZrW  
{ v!pT!(h4  
nStartPos = input.readLong(); <Eo;CaaF/  
nEndPos = input.readLong();
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} Z ?{;|Z5  
input.close(); IaU  
} |W/_S^C  
catch(IOException e){e.printStackTrace ();} coxMsDs  
catch(Exception e){e.printStackTrace ();} _"PTO&E  
} i7fQj, q  
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7  
private void processErrorCode(int nErrorCode) [kyF|3k~  
{ ^/3R/;?  
System.err.println("Error Code : " + nErrorCode); IR+dGqIjZb  
} yB7=8 Pcx  
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//停止文件下载 <
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public void siteStop() Fvy__qcHi  
{ Q`qHzb~%  
bStop = true; }'mBqn  
for(int i=0;i<nStartPos.length;i++) 1A4!zqT;  
fileSplitterFetch.splitterStop(); X;7gh>Q'4  
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} 3hOiHO ;  
} IRemF@  
//负责部分文件的抓取 xq2{0q  
**FileSplitterFetch.java X=Q)R1~6v  
*/ W27EU/+3  
package NetFox; {q%wr*  
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import java.io.*; ;/fZh:V2  
import java.net.*; dyRKmLb  
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public class FileSplitterFetch extends Thread { nk,X6o9%  
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String sURL; //File URL 0*MY4r|-  
long nStartPos; //File Snippet Start Position Ll%CeP  
long nEndPos; //File Snippet End Position <FIc!  
int nThreadID; //Thread's ID }1P>^I"[Y  
boolean bDownOver = false; //Downing is over  `Nn=6[]  
boolean bStop = false; //Stop identical QAigbSn]  
FileAccessI fileAccessI = null; //File Access interface <=A1d\   
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException D.zEE-cGyb  
{ ^uIP   
this.sURL = sURL; 4k5X'&Q  
this.nStartPos = nStart; <(dHh9$~  
this.nEndPos = nEnd; {ZiJnJX  
nThreadID = id; +85i;gO5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &FF%VUfQJ  
} luYkC@I@a  
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public void run() B#Cb`b"  
{ ;LRY h?  
while(nStartPos < nEndPos && !bStop) m?DI]sIv#  
{ cRPW  
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try{ jj2 [Zh/h  
URL url = new URL(sURL); q(sEN!^L`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P(BjXMd  
httpConnection.setRequestProperty("User-Agent","NetFox"); Umx~!YL!  
String sProperty = "bytes="+nStartPos+"-"; TbqH-R3W  
httpConnection.setRequestProperty("RANGE",sProperty); XKD0n^L[  
Utility.log(sProperty); A)9OkL
rc  
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InputStream input = httpConnection.getInputStream(); 22aS <@}  
//logResponseHead(httpConnection); 6-8,qk  
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byte[] b = new byte[1024]; FC
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int nRead; ]X y2km]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f]Jn\7j4  
{ a*?bnw?  
nStartPos += fileAccessI.write(b,0,nRead); {~J'J$hn8  
//if(nThreadID == 1) Dv~W!T i  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G?`{OW3:_  
} iIT7pq1  
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Utility.log("Thread " + nThreadID + " is over!"); i\~@2  
bDownOver = true; |q0F*\z3  
//nPos = fileAccessI.write (b,0,nRead); SU>2M
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} 7i-G5%w7  
catch(Exception e){e.printStackTrace ();} 8t)5b.PS  
} 8@b,>l$  
} M_ *KA  
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//打印回应的头信息 9
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public void logResponseHead(HttpURLConnection con) >6yA+?[:  
{ EWz,K]_'  
for(int i=1;;i++) imb.CYS74  
{ p>Z18  
String header=con.getHeaderFieldKey(i); Xy(8}  
if(header!=null) b
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); d\eTyN'rA  
Utility.log(header+" : "+con.getHeaderField(header)); :pz`bFJk  
else 95cIdF 6m  
break; tW$Di*
h  
} 4~8!3JH39  
} %?2:1o  
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public void splitterStop() nDG41)|  
{ Y8i'=Po%,  
bStop = true; _8QHx;}  
} IA6,P>}N  
!+R_Z#gB  
|.]g&m)y^h  
} 9nGS"E l{  
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/* $M:Ru@Du2  
**FileAccess.java N6R0$Br  
*//文件访问(定位，写) Zqi;by%  
package NetFox; 7Be\^%  
import java.io.*; xZE%Gf_U  
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public class FileAccessI implements Serializable{ K?J?]VCw  
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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 1EmZ/@k/Y  
RandomAccessFile oSavedFile; RCC~#b
b  
long nPos; j&y>?Y&Sb  
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public FileAccessI() throws IOException eVvDis  
{ FfSKE  
this("",0); O!3`^_.  
} 6\5"36&/rQ  
2EAY`}Rl6.  
 \LP?,<  
public FileAccessI(String sName,long nPos) throws IOException "k>;K,:  
{ #J w\pOn  
oSavedFile = new RandomAccessFile(sName,"rw"); `21$e  
this.nPos = nPos; n38l!m(.  
oSavedFile.seek(nPos); X"fSM #  
} ;p8,
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public synchronized int write(byte[] b,int nStart,int nLen) ^2<nn op  
{ ;)rs#T;$  
int n = -1; /9k}Ip  
try{ 41s[p56+@  
oSavedFile.write(b,nStart,nLen); Xxmvg.Nl  
n = nLen; nNP{>\x;"  
} o4d[LV4DS  
catch(IOException e) I]jK]]@  
{ ,]cb3nP  
e.printStackTrace (); 2
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} wPRs.(]_  
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return n; bqI| wGCA"  
} yq,%ey8  
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} jPyhn8Vw  
c ;@k\6  
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/* y|O)i I/g  
**SiteInfoBean.java .:?cU#.  
*/ }29Cm$p  
package NetFox; 3^%sz!jK+  
qcdENIy0b  
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public class SiteInfoBean { ?:1)=I<A4  
:eR[lR^4*  
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private String sSiteURL; //Site's URL 5^GFN*poig  
private String sFilePath; //Saved File's Path NX5NE2@^qH  
private String sFileName; //Saved File's Name %. -nZC  
private int nSplitter; //Count of Splited Downloading File 69tT'U3vb$  
VjhwafYC  
/c9%|<O%  
public SiteInfoBean() D-!#TN`Y  
{//nSplitter的缺省值为5 @[] A&)B  
//default value of nSplitter is 5 B$kp\yL  
this("","","",5); ukH?O)0O  
} x|oa"l^JZ"  
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v  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;th]/ G  
{ q*kieqG  
sSiteURL= sURL; ko<iG]Dv'  
sFilePath = sPath; JHCV7$RS  
sFileName = sName; ok+-#~VTn  
this.nSplitter = nSpiltter; <(<19t5.  
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} NA`E
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av*M#  
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public String getSSiteURL() T2$V5RyX  
{ bk#t+tuk  
return sSiteURL; ~jqh&u$(  
} /Vy8%   
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@`X-=GCl  
public void setSSiteURL(String value) LpJ_HU7@lk  
{ [@_zsz,`L  
sSiteURL = value; dGb]`*E  
}
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-}?
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public String getSFilePath() @$(/6]4p  
{ L'JEkji"  
return sFilePath; jSj (ZU6  
} L,F )l2  
1K;i/  
VK)K#!O8  
public void setSFilePath(String value) X|WAUp?  
{ GAlAFsB  
sFilePath = value; M!s@w
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} NNQro)Lpe  
&dV|~xA6N  
Czs4jHTa`  
public String getSFileName() 8'2lc  
{ srN>pO8u~  
return sFileName; g8{?;  
} Q1Jkt  
FH'jP`  
j;O{Hvvz  
public void setSFileName(String value) kd9GHN;7  
{ m_TZY_;  
sFileName = value; *yv@-lP5s  
} at/v.U|F  
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public int getNSplitter() Z:#-4CiP  
{ d8b'Gjwtw  
return nSplitter; ua['rOnU  
} / 4K*iq  
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public void setNSplitter(int nCount) ,~Y5vnaOQ  
{ xw5E!]~D  
nSplitter = nCount; (WK$ )f  
} %<e\s6|P:  
} *HmL8c  
\<VwGbzFi  
Q^v8n1  
/* x7J|  
**Utility.java O\L(I079  
*/ >qn@E?Uf  
package NetFox; i4.s_@2Y  
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public class Utility { 0+O)~>v  
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public Utility() )\uy 0+b  
{ F'Fc)9qFa<  
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} F5%-6@=  
:*1Gs,  
//线程睡眠 0-g,C=L  
public static void sleep(int nSecond) L.15EXAB  
{ 4(&00#Yxg2  
try{ C4Q^WU+$j  
Thread.sleep(nSecond); j2#Vdw|j  
} +U^dllL7  
catch(Exception e) f9D7T|J?10  
{ 7F3Hkvd[k  
e.printStackTrace (); "twV3R  
} p&_a kQj  
} Y_%\kM?7  
X8bo?0  
//日志 vsoj] R$C  
public static void log(String sMsg) Px=/fO G  
{ }tx~y-QQ  
System.err.println(sMsg); n=t%,[Op  
} b_Ba0h=  
nA
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public static void log(int sMsg) KEYM@,'  
{  fUb5KCZ  
System.err.println(sMsg); \I,<G7!0  
} 2Pi}<pG~
 
} 3 %dbfT j  
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>6ch[W5k@  
/* PpU : 4;en  
**TestMethod.java 4_t aCK  
*/ 1 EC
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package NetFox; ,)GCg@7B  
sNX$ =<E  
.1|'9@]lj4  
public class TestMethod { ]pb;q(?^  
kf-ZE$S4  
_V:D7\Gs  
public TestMethod() D9H|]W~  
{ ///xx/weblogic60b2_win.exe 3u{[(W}08  
try{ ,{8~TVO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +-ieaF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); C _[jQTr  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z0g]nYN%  
fileFetch.start(); (eO0Ic[c  
} ^5,ASU  
catch(Exception e){e.printStackTrace ();} |[o2S90  
[mWo&Ph[-  
mW8CqW\Q5  
} Q `E{Oo,  
/B1<N}  
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public static void main(String[] args) YLobBtXc9  
{ b55|JWfC`  
new TestMethod(); Vaq=f/  
} SC|cCK hqi  
} o"n^zG  
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