http断点续传简单实现（java)

/* / Zz2=gDY  
**SiteFileFetch.java |?s%8c'w=  
*/ ll1?I8}5|  
package NetFox; ?8-e@/E#x  
import java.io.*; & ?/h5<  
import java.net.*; YM3oqS D  
}n6BI}n  
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public class SiteFileFetch extends Thread { u):z1b3*?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean NxNR;wz>l  
long[] nStartPos; //开始位置 @MtF^y
  
long[] nEndPos; //结束位置 ^>GL<1 1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <^R\N#  
long nFileLength; //文件长度 ;Bcf~[ErM  
boolean bFirst = true; //是否第一次取文件 (z2)<_bXJ  
boolean bStop = false; //停止标志 rMe`HM@  
File tmpFile; //文件下载的临时信息 (S5'iksx  
DataOutputStream output; //输出到文件的输出流 }w8h^(+B  
}O2hhh_  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |1g2\5Re  
public SiteFileFetch(SiteInfoBean bean) throws IOException g.DgJX&i  
{ Xe=@I*  
siteInfoBean = bean; 7Yk6C5C  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); UbC)XiO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 85"DS-+e  
if(tmpFile.exists ()) dAEz hR[=  
{ /,Ln)?eD  
bFirst = false; 
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read_nPos(); hx)Ed  
} KPW: r#d  
else |t]-a%A=w  
{ 3(^9K2.s}  
nStartPos = new long[bean.getNSplitter()]; lxbbyy25  
nEndPos = new long[bean.getNSplitter()]; Q;m .m2  
} x18ei@c  
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} *}
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public void run() }y=7r!{@  
{ .a=M@;p  
//获得文件长度 1(q!.lPc  
//分割文件 `~@BU  
//实例FileSplitterFetch +]uy  
//启动FileSplitterFetch线程 B'
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//等待子线程返回 HP]Xh~aP  
try{ q n=6>wP  
if(bFirst) =C`v+NPM)|  
{ ,e.y4 vnU  
nFileLength = getFileSize(); JFYeOmR+l  
if(nFileLength == -1) WpTC,~-  
{ T]CvfvO
5  
System.err.println("File Length is not known!"); l*nSgUg  
} ,Oxdqxu7  
else if(nFileLength == -2) Aba6/  
{ *ArzXhs[  
System.err.println("File is not access!"); DKK200j  
} Lb2Bu>  
else ReSP)%oW  
{ HkEp}R  
for(int i=0;i<nStartPos.length;i++) *:\QD 8^  
{ !29 Rl`9
 
nStartPos = (long)(i*(nFileLength/nStartPos.length)); xFg=Tyq:  
} L?al2aopF  
for(int i=0;i<nEndPos.length-1;i++) } k5pfz  
{ ld9zOq  
nEndPos = nStartPos[i+1]; .YS[Md{  
} LgBs<2  
nEndPos[nEndPos.length-1] = nFileLength; dR$P-V\y`%  
} o"[qPZd>  
} OY[N%wr!  
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//启动子线程 $#t&W&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; z2"2Xqy<U  
for(int i=0;i<nStartPos.length;i++) R?l>
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{ $Q47>/CUc^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /8Vh G|Wb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !*CL>}-,  
nStartPos,nEndPos,i); 0CTI=<;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DCwldkdJN  
fileSplitterFetch.start(); VaX>tUW  
} c?IIaj!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c!kbHZ<Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); i~K~Czmok+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X_%78$N-a`  
nEndPos = " + nFileLength); ;K:.*sAa  
// fileSplitterFetch[nPos.length-1].start(); VLQfuh;  
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//等待子线程结束
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//int count = 0; Qz<v. _  
//是否结束while循环 oO= 6Kd+T  
boolean breakWhile = false; WBC'~h<@  
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$]Fe9E?   
while(!bStop) jq}5(*k
 
{ ={zYcVI  
write_nPos(); >aa-i
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Utility.sleep(500); [$] JvF  
breakWhile = true; C 
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for(int i=0;i<nStartPos.length;i++) VK$+Nm)  
{ zH|!O!3"4  
if(!fileSplitterFetch.bDownOver) JY>]u*=  
{ CrqWlO  
breakWhile = false; Dj<Vn%d*  
break; 7&T1RB'>  
} D, 3x:nK  
} Y9PG  
if(breakWhile) 6'qs=Ql  
break; z` gR*+  
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j\Q_NevV  
//count++; T}4RlIZF  
//if(count>4) yq;gBIiZ  
// siteStop(); lIOLR-:4j  
} h?$4\^/  
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m _:ib}  
System.err.println("文件下载结束！"); D$ `yxc  
} I^lb;3uR  
catch(Exception e){e.printStackTrace ();} jfgAI7;b  
} d_]MqH>R\  
>nTGvLOq  
\idg[&}l}  
//获得文件长度 n{UB^-}5  
public long getFileSize() 8+GlM+>4  
{ Pb[wysy  
int nFileLength = -1; ,T1t`  
try{ eqjl$QWPJS  
URL url = new URL(siteInfoBean.getSSiteURL()); r!#
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L4Kkbt<x  
httpConnection.setRequestProperty("User-Agent","NetFox"); eOLS  
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int responseCode=httpConnection.getResponseCode(); NCl={O9<j  
if(responseCode>=400) .Olq_wuH  
{ >eJk)q
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processErrorCode(responseCode); b`%/*  
return -2; //-2 represent access is error f+gyJ#R`  
} f#mY44:,C  
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String sHeader; PW.W.<CL  
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for(int i=1;;i++) 30F&FTW  
{ V-I_SvWv\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w"A'uFXLc  
//Utility.log(in.readLine()); j7uiZU;3Rx  
sHeader=httpConnection.getHeaderFieldKey(i); T_I"Tsv  
if(sHeader!=null) SDJAk&Z}R  
{ >Wy@J]Y#  
if(sHeader.equals("Content-Length")) IURi90Ir  
{ =DF7l<&km  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); t;E-9`N  
break; Af*^u|#  
} u^V`Ucd"R  
} vp-)$f&  
else @gs Kb*,  
break; sFB; /*C  
} zf2]|]*xz  
} \.Q"fd?a_D  
catch(IOException e){e.printStackTrace ();} f3*u_LO  
catch(Exception e){e.printStackTrace ();} *S{%+1F  
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Utility.log(nFileLength); &HW%0lTs%  
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return nFileLength; \Fc"Q@.u  
} VN;Sz,1Z  
kGX`y.-[  
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//保存下载信息（文件指针位置） %'EOFv]  
private void write_nPos() w,JB`jS)/  
{ KWhw@y-5j@  
try{ U7 Z_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +mV4T
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output.writeInt(nStartPos.length); ks'25tv}F  
for(int i=0;i<nStartPos.length;i++) SOeL@!_  
{ "K~+T\^|k  
// output.writeLong(nPos); SAXjB;VH6  
output.writeLong(fileSplitterFetch.nStartPos); 6P+8{?V&  
output.writeLong(fileSplitterFetch.nEndPos); ,uuQj]Dac+  
} 0UlaB sv  
output.close(); 4JP01lq'\  
} D<Ads  
catch(IOException e){e.printStackTrace ();} ^9"|tWf6O  
catch(Exception e){e.printStackTrace ();} 7
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} l=bB,7gL  
J;'?(xO3\  
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//读取保存的下载信息（文件指针位置） -zMXc"'C^k  
private void read_nPos() G4AX8@;U  
{ O/l|\n  
try{ 3P'.)=}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jskATA /  
int nCount = input.readInt(); cdzMao  
nStartPos = new long[nCount]; mVU(u_lh  
nEndPos = new long[nCount]; Px'%5TKN  
for(int i=0;i<nStartPos.length;i++) E%jOJA  
{ tse(iX/D  
nStartPos = input.readLong(); aI+:rk^  
nEndPos = input.readLong(); Fi(_A  
} rN}{v}n  
input.close(); +Bc/@.Q'  
} =s1"<hH}O)  
catch(IOException e){e.printStackTrace ();} $5cLhi"`  
catch(Exception e){e.printStackTrace ();} }q27M  
} 0>Ecm#  
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private void processErrorCode(int nErrorCode) ){R_o
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{ ?$F:S%eH  
System.err.println("Error Code : " + nErrorCode); `h :&H,N  
} >y%$]0F1  
0Q%'vBX\`  
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//停止文件下载 ZXHG2@E)  
public void siteStop() j:$2,?|5  
{ xzIs,i}U  
bStop = true; F!j@b!J8  
for(int i=0;i<nStartPos.length;i++) op&,&  
fileSplitterFetch.splitterStop(); yIqsZJj  
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b 3D:w{l  
} GEIMCg(TRj  
} kB"Sh_:m  
//负责部分文件的抓取 g8!!:fdu  
**FileSplitterFetch.java <F>\Vl:  
*/ yBht4"\Al  
package NetFox; B
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import java.io.*; O)&xT2'J  
import java.net.*; Yy>%dL  
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@5Ril9J[b  
public class FileSplitterFetch extends Thread { +;U}SR<  
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String sURL; //File URL B,|M  
long nStartPos; //File Snippet Start Position Yca9G?^\v  
long nEndPos; //File Snippet End Position 7Cp>iWV  
int nThreadID; //Thread's ID !W]># Pm  
boolean bDownOver = false; //Downing is over Joq9.%7Q  
boolean bStop = false; //Stop identical q.~.1 '`!  
FileAccessI fileAccessI = null; //File Access interface 26.iFt/:  
Z(*nZT,  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException X#1So.}c  
{ }B^s!y&b  
this.sURL = sURL; (Qq! u  
this.nStartPos = nStart; oQWS$\Rr.  
this.nEndPos = nEnd; `k_5Pz\  
nThreadID = id; DV*8Mkzg  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Nr3td`;  
} 7:{4'Wr@6|  
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public void run() m!N_TOl-^  
{ q;tsA"l  
while(nStartPos < nEndPos && !bStop) 
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{ = J).(E89  
t
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try{ v#YO3nD  
URL url = new URL(sURL); 1}KNzMHk9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (3c,
;koRR  
httpConnection.setRequestProperty("User-Agent","NetFox"); 52wq<[#tK  
String sProperty = "bytes="+nStartPos+"-"; dSk\J[D  
httpConnection.setRequestProperty("RANGE",sProperty); r"Pj,}$A  
Utility.log(sProperty); %49@  
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InputStream input = httpConnection.getInputStream(); c<DsCz
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//logResponseHead(httpConnection); +lO Y IQ  
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byte[] b = new byte[1024]; {B?%r[nW  
int nRead; 06 K8|K  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4#;rv$ {  
{ T!(I\wz;Bo  
nStartPos += fileAccessI.write(b,0,nRead); mL18FR N  
//if(nThreadID == 1) 7<|1 xOT  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A$Es(<'9g  
} V4/P  
v?fB:[dG  

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Utility.log("Thread " + nThreadID + " is over!"); REQ2pfk0  
bDownOver = true; Uu>YE0/)  
//nPos = fileAccessI.write (b,0,nRead);  f==o  
} [$8*(d"F'  
catch(Exception e){e.printStackTrace ();} Q:>;d-D|1  
} zP rT0  
} JWlH(-U4|  
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//打印回应的头信息 u2JkPh&!rq  
public void logResponseHead(HttpURLConnection con) X[h=UlF  
{ .Z'CqBr[:  
for(int i=1;;i++) 6"-LGK:  
{ `:i|y  
String header=con.getHeaderFieldKey(i); K)l{3\9l|  
if(header!=null) P]]9Sqo7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Qn[4&nUD  
Utility.log(header+" : "+con.getHeaderField(header)); P,CJy|[L  
else p Ic;9  
break; *G'zES0x  
} @T?:[nPf&F  
} R4E0avt  
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public void splitterStop() _+z@Qn?#6h  
{ $J=9$.4"  
bStop = true; = fuF]yL%  
} 7s<v06Wo  
\
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} |cWW5\/  
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/* [-s0'z  
**FileAccess.java rTDx|pvYx  
*//文件访问(定位，写) &zb_8y,  
package NetFox; +_ K7x5g  
import java.io.*; F{bET  
,#gA(B#  
j 7a;g7.  
public class FileAccessI implements Serializable{ ZKAIG=l&!  
q fadsVp  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 at6f(+  
RandomAccessFile oSavedFile; }1N)3~  
long nPos; `@")R-  
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public FileAccessI() throws IOException ?n?Ep[D  
{ lOI(+74  
this("",0); 8 x|NR?  
} Vnv<]D zC  
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public FileAccessI(String sName,long nPos) throws IOException 2ZNTg@o  
{ 0(@8  
oSavedFile = new RandomAccessFile(sName,"rw"); DK*2d_  
this.nPos = nPos; 9i,QCA  
oSavedFile.seek(nPos); !@ai=p  
} 4LUFG  
p
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6.KR(V  
public synchronized int write(byte[] b,int nStart,int nLen) \hv*`ukF  
{ #u|;YC  
int n = -1; Z;7f D  
try{ W*`2lf  
oSavedFile.write(b,nStart,nLen); P[#V{%f*5  
n = nLen; SZ1+h TY7d  
} :g+R}TR[i  
catch(IOException e) 9p>3k&S  
{ *2
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e.printStackTrace (); vRRi"bo  
} 8'Z9Z*^h#x  
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return n; KB*[b  
} #E{OOcM  
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} }4A+J"M4y  
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+)L 'qbCSM  
/* S[X bb=n  
**SiteInfoBean.java S-.!BQ@RMZ  
*/ $LFzpg  
package NetFox; @"'1"$  
y?CEV-3+  
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public class SiteInfoBean { ,t*
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private String sSiteURL; //Site's URL Y;xVB" (  
private String sFilePath; //Saved File's Path $N+a4  
private String sFileName; //Saved File's Name Le|Ho^h,Y
 
private int nSplitter; //Count of Splited Downloading File .QRQvtd.  
ran Q_\  
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public SiteInfoBean() 6yv*AmFh  
{//nSplitter的缺省值为5 ,%v  
//default value of nSplitter is 5 AS
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this("","","",5); 9_5Fl,u z  
} Tj<W4+p{  
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R}  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) iN<&  
{ pR
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sSiteURL= sURL; y5BNHweaRb  
sFilePath = sPath; 8iqx*8}  
sFileName = sName; o_bj@X  
this.nSplitter = nSpiltter; /DQoM@X  
9_KUUA  
1;]cYIq  
} MftX~+  
F>96]71 2  
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public String getSSiteURL() w[~$.FM/  
{ v&xk?F?WU,  
return sSiteURL; X<#Q~"  
} z<sf}6q  
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~y$B#.l  
public void setSSiteURL(String value) -81usu&NH  
{ -9.S?N'T>;  
sSiteURL = value; tm#T8iF  
} NVcL9"ht*@  
%fJ*Ql4M  
.Rd@,3  
public String getSFilePath() Beiz*2-}a  
{ xzz[!yJjG  
return sFilePath; azS"*#r6}  
} )$#ov-]  
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`:}GE@]  
public void setSFilePath(String value) |A8xy#  
{ 4F??9o8}  
sFilePath = value; )l\BZndf  
} H}dsd=yO  
do+HPnfDzU  
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public String getSFileName() 5m=3{lBi  
{ *&% kkbA  
return sFileName; 8ooj)  
} 9"I/jd
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public void setSFileName(String value) .NiPaUzc<  
{ z X2BJ  
sFileName = value; O)Nj'Hcu  
} zX{
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public int getNSplitter() t(\d;ybyx  
{ x5c pv  
return nSplitter; ])7t!<  
} [`6|~E"F  
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public void setNSplitter(int nCount) z<m,X
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{ f:KKOLm  
nSplitter = nCount; =xS(Er`r  
} &
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} =L#tSa=M"  
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/* )67Kd]  
**Utility.java BBnj}XP*4  
*/ /IxMRi=  
package NetFox; 4["$}O5  
qg 4:Vq  
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public class Utility { CD +,&id  
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public Utility() sc@v\J;k  
{ s~6?p% 2]  
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} `2o/W]SSk  
c}U&!R2p{  
//线程睡眠 bO>Mvf  
public static void sleep(int nSecond) 3R !Mfz*  
{ V/.Y]dN5  
try{ E@}t1!E<  
Thread.sleep(nSecond); S@k4k^Vg  
} @-NdgM<  
catch(Exception e) `|8)A)ZVT  
{ 0mF3Vs`-Q  
e.printStackTrace (); IMmoq={(z  
} A%Pjg1(uX  
} vnw83a%3  
`$JPF Z  
//日志 ((SN We  
public static void log(String sMsg) isLIfE>  
{ _ncqd,&z  
System.err.println(sMsg); RQ X  
} nBgksB*A  
?}D@{%O3T  
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public static void log(int sMsg) f[6;)ZA  
{ 5 UpN/\He  
System.err.println(sMsg); .8<bz4  
} V44IA[  
} w6F4o;<PR  
q=M!YWz  
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/* ^cz#PNB  
**TestMethod.java 'gxSHqeI2  
*/  5%mc|  
package NetFox;  O3bo3Cm$  
c_s=>z  
q~^Jd=cB\  
public class TestMethod { bJ*jJl x  
GPy+\P`  
nbj&3z,  
public TestMethod() \S{ise/U  
{ ///xx/weblogic60b2_win.exe C_rlbl;T  
try{ T$U,rOB"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Du k v[/60  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ArDkJ`DE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z!0D97^  
fileFetch.start(); E?l_*[G  
} xL3-(K6e
 
catch(Exception e){e.printStackTrace ();} ycg5S rg  
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} *,.WI
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public static void main(String[] args) @" UoQ_h%  
{ 3R1v0  
new TestMethod(); Cu3^de@h  
} EtjN :p|$  
} _Qs=v0B//  
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