http断点续传简单实现（java)

/* -r<8mL:yW  
**SiteFileFetch.java j>;1jzr2}  
*/ -ak.wwx\  
package NetFox; FWW@t1)  
import java.io.*; /iM1   
import java.net.*; G\MeJSt*  
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= FV12(U  
public class SiteFileFetch extends Thread { K)   
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SiteInfoBean siteInfoBean = null; //文件信息Bean 9y&;6V.'  
long[] nStartPos; //开始位置 Xw'sh#i2  
long[] nEndPos; //结束位置 $8U$.~v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 m-\_L=QzM  
long nFileLength; //文件长度 ^j${#Q  
boolean bFirst = true; //是否第一次取文件 F*#!hWtb  
boolean bStop = false; //停止标志 mMXDzAllB  
File tmpFile; //文件下载的临时信息 KzV|::S^  
DataOutputStream output; //输出到文件的输出流 C^,baCX  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） iOEBjj;C  
public SiteFileFetch(SiteInfoBean bean) throws IOException :3R3>o6m  
{ a@jM%VZ  
siteInfoBean = bean; OET/4(C  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); '@+q_v@Jl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ew{*)r)m  
if(tmpFile.exists ()) d9S?dx  
{ w=(dJ(7gu  
bFirst = false; BNjMq  
read_nPos(); H.XyNtJ  
} <)a$5"AP  
else OqMdm~4B!j  
{ Uaux0W  
nStartPos = new long[bean.getNSplitter()]; ]U'zy+  
nEndPos = new long[bean.getNSplitter()]; QeFt WjlqC  
} FO[ s;dmzu  
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} F7jkl4  
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public void run() ,7s+-sRG  
{ |,`"Omb9+m  
//获得文件长度 ^pu8\K;~  
//分割文件 w<THPFFF"  
//实例FileSplitterFetch Wd!Z
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//启动FileSplitterFetch线程 $PRd'YdL/  
//等待子线程返回 k=kkF"  
try{ =s*c(>  
if(bFirst) G7`m
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{ J5jI/
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nFileLength = getFileSize(); h(AL\9{=}  
if(nFileLength == -1) R"HV|Dm|m  
{ `u_MdB}<x;  
System.err.println("File Length is not known!"); &F#eYEuy  
} &E0^Jz  
else if(nFileLength == -2) +RM!j9Rq  
{ MHt ~ZVH  
System.err.println("File is not access!"); @|"K"j#  
} zi`q(
[  
else >r(`4
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{ _i7yyt;h  
for(int i=0;i<nStartPos.length;i++) Z?qLn6y1W  
{ 1>\V>g
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); |ITCw$T  
} Q.jThP`p  
for(int i=0;i<nEndPos.length-1;i++) -wx~*  
{ :%AEwRZ  
nEndPos = nStartPos[i+1]; @N<h`vDa  
} dQrz+_  
nEndPos[nEndPos.length-1] = nFileLength; ;AVIt!(L~V  
} LU8[$.P  
} tMP"9JE,  
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q_  
//启动子线程 W+8s>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r7V
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for(int i=0;i<nStartPos.length;i++) bM?29cs  
{ GSSmlJ`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8EJP~bt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), |%|Vlu  
nStartPos,nEndPos,i); x;:jF_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ADOA&r[  
fileSplitterFetch.start(); A2L"&dl  
} ^+d]'$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tKuJ &I~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~@Bw(!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lcEK&AtK  
nEndPos = " + nFileLength); Yc6.v8a  
// fileSplitterFetch[nPos.length-1].start(); u.n'dF-  
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Z Q*hrgQ  
//等待子线程结束 e, 2/3jO  
//int count = 0; kd"nBb=
 
//是否结束while循环 F/LMk8RgR  
boolean breakWhile = false; `S-%}eUv  
+!ljq~%  
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while(!bStop) { Dm@_&  
{ $.w$x1  
write_nPos(); ]LxE#R5V  
Utility.sleep(500); OJA_OqVp$K  
breakWhile = true; &M3KJ I0L  
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for(int i=0;i<nStartPos.length;i++) f<rn't{  
{ 9Qu(RbDqC  
if(!fileSplitterFetch.bDownOver) =<PEvIn  
{ stW G`>X  
breakWhile = false; s~>1TxJe  
break; NySa%7@CD  
} #UwX~  
} :r "GZ  
if(breakWhile) ;-"q;&1e  
break; ]o=ON95ja  
O x`K7$)  
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//count++; L[nDjQn"  
//if(count>4) 'xnI Nu  
// siteStop(); 7p!ROl^  
} cvT@`1  
H n]( )/  
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System.err.println("文件下载结束！"); YjL'GmL<  
} [Pjitw/?  
catch(Exception e){e.printStackTrace ();} v#s*I/kw  
} a-FI`Dv  
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//获得文件长度 :O&jm.2m  
public long getFileSize() T2rBH]5  
{ iV#A-9  
int nFileLength = -1; kQd|qZ=:w  
try{ i0+e3!QU  
URL url = new URL(siteInfoBean.getSSiteURL()); I#;dS!W"'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7mXXMm  
httpConnection.setRequestProperty("User-Agent","NetFox"); zAklS 7L  
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int responseCode=httpConnection.getResponseCode(); :IJ<Mmb  
if(responseCode>=400) N`?/kubD  
{ 0T(+
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processErrorCode(responseCode); id8QagJ  
return -2; //-2 represent access is error ,3-^EfccW  
} @b.,pwZF  
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String sHeader; ?ILjt?X8  
&!WRa@x0I  
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for(int i=1;;i++) $%31Gk[I  
{ 
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Rmn{Vui9\  
//Utility.log(in.readLine()); r7?nHF  
sHeader=httpConnection.getHeaderFieldKey(i); o37oRv]  
if(sHeader!=null) Pn.DeoHme  
{ {=Jo!t;f  
if(sHeader.equals("Content-Length")) coPdyw'9&  
{ Ck%if  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Q_iN/
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break; -
}!miV  
} OX]P;#4tU  
} BaIuOZ@,  
else s]kzXzRC?  
break; cjg~?R  
} P,-5af*;  
} 8>x'. 8  
catch(IOException e){e.printStackTrace ();} =0PGE#d{t  
catch(Exception e){e.printStackTrace ();} w >2G@  
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Utility.log(nFileLength); P3=#<Q.  
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return nFileLength; I''n1v?N  
}
,1Z([R*  
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//保存下载信息（文件指针位置） VEIct{  
private void write_nPos() &s?uMWR  
{ CP%^)LX *  
try{ 4~FRE)8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $>yfu=]?  
output.writeInt(nStartPos.length); % C2Vga#  
for(int i=0;i<nStartPos.length;i++) NR k~  
{ d-tg^Ot#  
// output.writeLong(nPos); ,t wB" *  
output.writeLong(fileSplitterFetch.nStartPos); L1(-xNUo_i  
output.writeLong(fileSplitterFetch.nEndPos); ^_P?EJ,)`  
} Qf~$9?z  
output.close(); f>ktv76  
} n4+q7  
catch(IOException e){e.printStackTrace ();} U{[YCs fk  
catch(Exception e){e.printStackTrace ();} k[a<KbS  
} {}Is&^3Z  
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//读取保存的下载信息（文件指针位置） =l*xM/S  
private void read_nPos() VzHrKI  
{ zYY]+)k?  
try{ G?XA",AC  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Mb\(52`)Q  
int nCount = input.readInt(); <Y1Plc  
nStartPos = new long[nCount]; GtZ.'?-  
nEndPos = new long[nCount]; 1%N*GJlwJ  
for(int i=0;i<nStartPos.length;i++) 'OP0#`6`  
{ a9{NAyl<oo  
nStartPos = input.readLong(); V!^0E.?a  
nEndPos = input.readLong(); ."B{U_P&  
} &<uLr *+*  
input.close(); +YW;63"
o  
} iJ8Z^=>  
catch(IOException e){e.printStackTrace ();} )mBYW}} T  
catch(Exception e){e.printStackTrace ();} zSfUM.fM  
} `W~  
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private void processErrorCode(int nErrorCode) h| wdx(4  
{ ?#Z4Dg 9|  
System.err.println("Error Code : " + nErrorCode); .lP',hn  
} VWHpfm[r%  
^5TVm>F@3  
q jc4IW t~  
//停止文件下载 ;l @lA)i  
public void siteStop() ivq(eKy  
{ 'plUs<A  
bStop = true; WR"1d\m:  
for(int i=0;i<nStartPos.length;i++) :0 n+RL*5  
fileSplitterFetch.splitterStop(); N5sVRL"7  
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} L2EQ 9i'[  
} h{ix$Xn~  
//负责部分文件的抓取 @d 7V@F0d  
**FileSplitterFetch.java C<(oaeQY  
*/ Fih pp<  
package NetFox; wW)(mY?   
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import java.io.*; L{8_6s(:  
import java.net.*; FibZT1-k  
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public class FileSplitterFetch extends Thread { d*gv.mE  
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String sURL; //File URL >|kD(}Axf  
long nStartPos; //File Snippet Start Position `kQosQV  
long nEndPos; //File Snippet End Position gz[3xH~  
int nThreadID; //Thread's ID J-dB  
boolean bDownOver = false; //Downing is over (,QWK08  
boolean bStop = false; //Stop identical !\BZ_guz  
FileAccessI fileAccessI = null; //File Access interface YJ"D"QD  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException JOt(r}gU  
{ Y01!D"{\  
this.sURL = sURL; SiX<tj#HH\  
this.nStartPos = nStart; ug2W{D  
this.nEndPos = nEnd; Q35\w
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nThreadID = id; p2t04p!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H2Wlgt  
} C7NSmZ  
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public void run() M;ADL|  
{ ~:T@SrVI  
while(nStartPos < nEndPos && !bStop) LPJ7V`!k  
{ b=:ud[h  
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try{ ~,1Sw7rE  
URL url = new URL(sURL); -X$EE$:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wxh\CBxG  
httpConnection.setRequestProperty("User-Agent","NetFox"); Fl=H5HR  
String sProperty = "bytes="+nStartPos+"-"; UiH7  
httpConnection.setRequestProperty("RANGE",sProperty); h^tCF=S  
Utility.log(sProperty); DWKQ>X6  
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InputStream input = httpConnection.getInputStream(); .aY$-Y<  
//logResponseHead(httpConnection); <Jhd%O
 
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byte[] b = new byte[1024]; Uz!3){E  
int nRead; 0@cIj ]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) pIcg+~  
{
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nStartPos += fileAccessI.write(b,0,nRead); HBE[q#  
//if(nThreadID == 1) bT2G G  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \N0vA~N.  
} uWdF7|PN7  
04|ZwX$>+  
<.4(#Ebd  
Utility.log("Thread " + nThreadID + " is over!"); Bgc]t
  
bDownOver = true; <F0^+Pf/  
//nPos = fileAccessI.write (b,0,nRead); EA6l11{Gk1  
} [q[37;ZEQ  
catch(Exception e){e.printStackTrace ();} H"AL@=  
} ")uKDq  
} 9!Mh(KtQ  
(=7"zECq#  
g[pU5%|"[  
//打印回应的头信息 -\?-  
public void logResponseHead(HttpURLConnection con) xWzybuLp  
{ m- <y|3  
for(int i=1;;i++) 
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{ ^*.$@M  
String header=con.getHeaderFieldKey(i); Ju47}t%HB  
if(header!=null) VM\R-[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~bb6NP;'L  
Utility.log(header+" : "+con.getHeaderField(header)); P5_Ajb(@'  
else { %X2K  
break; lF!
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} @s-P!uCaT  
} "V]*ov&[  
z fSE7i0  
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public void splitterStop() m1%r
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{ Yt
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bStop = true; E! NtD).=S  
} hp'oiR;
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} uKk#V6
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/* 6J,h}S  
**FileAccess.java T"Y#u  
*//文件访问(定位，写) iLSUz j`  
package NetFox; <7J3tn B  
import java.io.*; H;nzo3x  
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public class FileAccessI implements Serializable{ 1 gjaTPwY  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,ZJ}X 9$<  
RandomAccessFile oSavedFile; iptA#<Yj  
long nPos; L!Y|`P#Yr  
M,H8ZO:R  
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public FileAccessI() throws IOException 2v ~8fr4
  
{ ,nteIR'??  
this("",0); u?72]?SM  
} K _VIk'RB  
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public FileAccessI(String sName,long nPos) throws IOException pE<a:2J  
{ .2@T|WD!Ah  
oSavedFile = new RandomAccessFile(sName,"rw"); 49*f=gpGj2  
this.nPos = nPos; JE9v+a{7  
oSavedFile.seek(nPos); ZNw|5u^N  
} )m7%cyfC  
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public synchronized int write(byte[] b,int nStart,int nLen) /(s |'"6  
{ 2: gh q  
int n = -1; -"nkC  
try{ IwnDG;+Ap  
oSavedFile.write(b,nStart,nLen); S,:!H@~B  
n = nLen; 0<`qz |_h  
} G^d3$7  
catch(IOException e) /P,1KVQPh  
{ 7/<~s]D[%  
e.printStackTrace (); TzaeE  
} 75Z|meG~  
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return n; 3'.3RKV  
} R&W%E%uj  
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} ~Re4
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'Jf LTG.  
/* n+=qT$w)  
**SiteInfoBean.java $;Fx Zkp  
*/ Xf&YcHo  
package NetFox; X:Z3R0  
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public class SiteInfoBean { Wd;t(5Xl  
/a32QuS  
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private String sSiteURL; //Site's URL (k!7`<k!Y  
private String sFilePath; //Saved File's Path D@uVb4uK  
private String sFileName; //Saved File's Name moxmQ>xoH  
private int nSplitter; //Count of Splited Downloading File %l&oRBC  
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public SiteInfoBean() xwD`R*  
{//nSplitter的缺省值为5 ir.RO7f  
//default value of nSplitter is 5 cL#-vW<s3  
this("","","",5); *RS/`a;,  
} Fya*[)HBo  
}'wZ)N@  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) c9EtUv~  
{ -b!Z(}JK  
sSiteURL= sURL; ^)]U5+g?  
sFilePath = sPath; F,S)P`?  
sFileName = sName; u=nd7:bv  
this.nSplitter = nSpiltter; }@6Ze$>  
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26aDPTP$<  
} YNV, dKB  
++b[>};  
k vZw4Pk  
public String getSSiteURL() >U*p[FGW  
{ 5;KJ0N*-  
return sSiteURL; vaiw*?jV  
} NL:-3W7vf  
e4=FO;%  
xRc+3Z= N  
public void setSSiteURL(String value) !o`7$`%Wz\  
{ w3q'n%  
sSiteURL = value; mTu>S  
} 9+9g(6
 
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public String getSFilePath() &X:;B'   
{ =M-=94  
return sFilePath; F&!vtlV)  
} ]CLM'$  
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public void setSFilePath(String value) >(P(!^[f  
{ lv/
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sFilePath = value; l9uocP:D  
} 3 orZBT  
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public String getSFileName() 99*k&mb  
{ ( gg )?  
return sFileName; ;8PO}{rD  
} giu{,gS0?M  
,&@GxiU  
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public void setSFileName(String value) |Io:D:  
{ AR( gI]1  
sFileName = value; j"6|$Ze8  
} `PAQv+EYz  
t<fah3hl  
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public int getNSplitter() m2^vH+wD  
{ >x*[izr/K  
return nSplitter; 9soEHG=P  
} XcT!4xG0  
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public void setNSplitter(int nCount)
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{ ZMlBd}H  
nSplitter = nCount; 36{OE!,i  
} ;SI (5rS?  
} EGgw#JAi#t  
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/* h(yFr/  
**Utility.java hK)'dG*  
*/ BA1H)%  
package NetFox; L}{3_/t  
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public class Utility { 94&t0j_  
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public Utility() %J2Ad  
{ U&6A)SW,k  
(${
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} -V;Y4,:c  
ox`Zs2-a  
//线程睡眠 GdUsv  
public static void sleep(int nSecond) Wap4:wT  
{ ,gZp/yJ;  
try{ 'gor*-o:wu  
Thread.sleep(nSecond); ZqrS]i@$  
} ,gNZHKNq  
catch(Exception e) 8y6
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{ @"NP`#
 
e.printStackTrace (); p
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} D~ 3@v+d  
} eE'>kP}  
r
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//日志 &&l ZUR,`  
public static void log(String sMsg) L&s~j/pR  
{ {1Cnrjw  
System.err.println(sMsg); c-JXWNz  
} mZB:j]T  
\Y"S4<"R  
Drtg7v{@\  
public static void log(int sMsg) OKm,iIp]  
{ G{6@]72  
System.err.println(sMsg); )jl@hnA  
} Xj+_
"0 #  
} I2HV{1(i  
i/-IjgM"-  
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/* !yj1X Ar  
**TestMethod.java  ij:a+T  
*/ @C@9Tw2Y  
package NetFox; QyL]-zNg  
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public class TestMethod { N KgEs  
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public TestMethod() Xh}q/H<  
{ ///xx/weblogic60b2_win.exe USEmD5q  
try{ !VI
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }iDRlE,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); C ibfuR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Dti-*LB1  
fileFetch.start(); |)To 0Z  
} MkFWZ9c3  
catch(Exception e){e.printStackTrace ();} 3HXeBW  
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} V0m1>{  
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`:Wyw<^  
public static void main(String[] args) !NNPg?Y  
{ z =H?@z  
new TestMethod(); `f}ZAX  
} !-T#dU  
} 8*&-u +@%  
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