http断点续传简单实现（java)

/* Z<`QDBN"4  
**SiteFileFetch.java ~OXPn9qPp  
*/ YH@^6Be9  
package NetFox; (<|,LagTuc  
import java.io.*; s~3"*,3@  
import java.net.*; :U=*@p4?  
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public class SiteFileFetch extends Thread { X-=49)  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ^p)#;$6b  
long[] nStartPos; //开始位置 'hR0JXy  
long[] nEndPos; //结束位置 s@zO`uBc  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,R.rxoO  
long nFileLength; //文件长度 9A~w2z\G  
boolean bFirst = true; //是否第一次取文件 M0yv=g  
boolean bStop = false; //停止标志 ?zex]!R  
File tmpFile; //文件下载的临时信息 MX? *jYl  
DataOutputStream output; //输出到文件的输出流 u8.F_'`z  
,BUrZA2\U$  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） > a;iX.K  
public SiteFileFetch(SiteInfoBean bean) throws IOException I3HO><of  
{ 4O<sE@X  
siteInfoBean = bean; A3)"+`&PUl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ":0u%E?s  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^hXm=r4ozR  
if(tmpFile.exists ()) |sdG<+  
{ .' }jd#  
bFirst = false; yIhPB8QL  
read_nPos(); `WIZY33V  
} ?VlGTMaS+  
else Q3Pu<j}Y  
{ 7Xx3s@  
nStartPos = new long[bean.getNSplitter()]; rY6x):sC  
nEndPos = new long[bean.getNSplitter()]; |.VSw  
} !B 4zU:d  
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} ^3
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public void run() rCwE$5 b  
{ .<zKBv  
//获得文件长度 >MJ#|vO  
//分割文件 XVkw/l  
//实例FileSplitterFetch b3EGtC}^  
//启动FileSplitterFetch线程 pJx7S sW  
//等待子线程返回 5CZyA`3V^5  
try{ dzEi^* (8  
if(bFirst) \o}T0YX  
{ yfK}1mx)j  
nFileLength = getFileSize(); sEFQ8S  
if(nFileLength == -1) }%p:Xv@X!  
{ kL%ot<rt)w  
System.err.println("File Length is not known!"); GQ;0KIN  
} &y5"0mA  
else if(nFileLength == -2) u Jqv@GFv  
{ 5afD;0D5TI  
System.err.println("File is not access!"); uG^CyM>R`  
} 7b+r LyS0  
else *mzi ?3  
{ d!E_EoOi  
for(int i=0;i<nStartPos.length;i++) l3sF/zkH  
{ `wXK&R<`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); HwHF8#D*l  
} uR ?W|a  
for(int i=0;i<nEndPos.length-1;i++) *[{j'7*cc  
{ W}f)VC;D  
nEndPos = nStartPos[i+1]; l::q F 0  
} =SXdO)%2  
nEndPos[nEndPos.length-1] = nFileLength; E +_n@t"  
} G9f
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} i
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#73pryXV  
//启动子线程 6N#hN)/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; B+K6(^j,,y  
for(int i=0;i<nStartPos.length;i++) ^+SE_-+]  
{ o/w3b8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7v*gwBH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bZ\R0[0  
nStartPos,nEndPos,i); QselW]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); x~V[}4E%>  
fileSplitterFetch.start(); ECOJ .^  
} I/`"lAFe  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M76p=*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {V6&((E8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hZx&j{  
nEndPos = " + nFileLength); iApq!u,  
// fileSplitterFetch[nPos.length-1].start(); wXKtQ#o}  
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//等待子线程结束 (9Zvr4.f7  
//int count = 0; i>YS%&O?  
//是否结束while循环 #7]Jz.S  
boolean breakWhile = false; n93q8U6m/U  
J8qFdNK  
 >Uw:cq  
while(!bStop) 0$*7lQ<a#M  
{ x4WCAqi/2  
write_nPos(); >Zb!?ntN`t  
Utility.sleep(500); {
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breakWhile = true; UzxL" `^7  
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for(int i=0;i<nStartPos.length;i++) qX,q*hr-  
{ V&*IZt&  
if(!fileSplitterFetch.bDownOver) "`>6M&`U  
{ o{
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breakWhile = false; ~CNB3r5R  
break; cnu&!>8V  
} C%z)D1-  
} y bhFDx  
if(breakWhile) !"N,w9MbD  
break; hY`<J]-'`  
@IL04' \  
|'h(S|  
//count++; N3%#JdzZ$  
//if(count>4) 1}d F,e  
// siteStop(); Db|f"3rq?  
} Fi i(dmn  
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System.err.println("文件下载结束！"); y!b2;- Dp  
} t\M6 d6  
catch(Exception e){e.printStackTrace ();} s<!A<+Sh  
} 
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//获得文件长度 ),x0G*oebj  
public long getFileSize() eKiDc=@  
{ ``/L18  
int nFileLength = -1; 'gY?=,dF>  
try{ p/{%%30ke  
URL url = new URL(siteInfoBean.getSSiteURL()); I):c#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WsHDIp  
httpConnection.setRequestProperty("User-Agent","NetFox"); x{pj`'J)  
.#&)%}GC  
nE]rPRU}[  
int responseCode=httpConnection.getResponseCode(); 7J);{ &x9h  
if(responseCode>=400) Ae2N"%Ej  
{ iHv+I~/
 
processErrorCode(responseCode); uuM1_nD[  
return -2; //-2 represent access is error 1
)~|{X+~  
} %Xc,l Y1?  

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String sHeader; #._JB-,'  
>#h,q|B  
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for(int i=1;;i++) XpANaqH\  
{ o33t~@RX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); iQO4IT   
//Utility.log(in.readLine()); yy5|8L  
sHeader=httpConnection.getHeaderFieldKey(i); :}NheRi  
if(sHeader!=null) #w''WOk@ZG  
{ '-"[>`[q  
if(sHeader.equals("Content-Length")) &$XTe2  
{ : ;8L1'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); eBa#Z1Z  
break; qlM<X?  
} JL {H3r&/S  
} {`):X_$T  
else `%\CO`  
break; ZY<RNwu  
} (g@X.*c8  
} P<
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catch(IOException e){e.printStackTrace ();} +tk`$g  
catch(Exception e){e.printStackTrace ();} S0StC$$1  
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Utility.log(nFileLength); 5BA:^4zr?  
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return nFileLength; %KVmpWku  
} B.=n U  
kB?/_a`]  
H*G(`Zl}  
//保存下载信息（文件指针位置） sf$hsPC^  
private void write_nPos() 7#wB  
{ E-^(VZ_Xj  
try{ +8
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output = new DataOutputStream(new FileOutputStream(tmpFile)); 0e&&k  
output.writeInt(nStartPos.length); X> 98`  
for(int i=0;i<nStartPos.length;i++) t;Z9p7rk  
{ &bq1n_  
// output.writeLong(nPos); [*u\S  
output.writeLong(fileSplitterFetch.nStartPos); :ek^M
(  
output.writeLong(fileSplitterFetch.nEndPos); d
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} e<uf)K=(
C  
output.close(); NL:dyV}  
} )a0l:jEOc  
catch(IOException e){e.printStackTrace ();} i+5Qs-dHA  
catch(Exception e){e.printStackTrace ();} %7-(c  
} '0~?zP  
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2!LDrvPP  
//读取保存的下载信息（文件指针位置） t{B@k[|  
private void read_nPos() f6J]=9jU  
{ |X*y-d77W  
try{ j=U"t\{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &0f/F:M  
int nCount = input.readInt(); (`slC~"  
nStartPos = new long[nCount]; 3=U#v<  
nEndPos = new long[nCount]; ;o)'dK  
for(int i=0;i<nStartPos.length;i++) tq,^!RSbZ  
{ U]+IP;YS  
nStartPos = input.readLong(); Kg~D~ +j  
nEndPos = input.readLong(); TDZ==<C  
} "*/IP9?]  
input.close(); prt(xr4@  
} @f"[*7Q`/  
catch(IOException e){e.printStackTrace ();} t$,G%micj  
catch(Exception e){e.printStackTrace ();} \:F$7 *Ne  
} pRh9+1EM;  
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private void processErrorCode(int nErrorCode) }D!tB  
{ 3n)Kzexh  
System.err.println("Error Code : " + nErrorCode); 9;I%Dv  
} r[^.\&-  
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9W(&g)`  
//停止文件下载 LH}9&FfjU  
public void siteStop() |15!D  
{ XP
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bStop = true; _1Rw~}O  
for(int i=0;i<nStartPos.length;i++) 8a@k6OZ  
fileSplitterFetch.splitterStop(); K_ymA,&()  
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} #J3}H  
} OO?N)I
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//负责部分文件的抓取 V:j^!*  
**FileSplitterFetch.java :qqG%RB  
*/ "(W;rl  
package NetFox; Hmm0H6&u  
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)M"NMUuU"  
import java.io.*; 3QZm *. /"  
import java.net.*; ?(R#  
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public class FileSplitterFetch extends Thread { XZ8rM4 ]
 
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String sURL; //File URL .]KC*2  
long nStartPos; //File Snippet Start Position $X-PjQb1Bb  
long nEndPos; //File Snippet End Position ?mC'ZYQI  
int nThreadID; //Thread's ID G na%|tUz|  
boolean bDownOver = false; //Downing is over \kUQe-:he  
boolean bStop = false; //Stop identical EUI*:JU-  
FileAccessI fileAccessI = null; //File Access interface f{L;,  
ipMSMk7gx  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException aqk$4IG  
{ T?[;ej:  
this.sURL = sURL; Hicd -'  
this.nStartPos = nStart; Bca$%3
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this.nEndPos = nEnd; C[%&;\3S@  
nThreadID = id; xc@$z*w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '3^q
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} kq(
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public void run() n7~3~i`D;  
{ eLh35tw  
while(nStartPos < nEndPos && !bStop) mT@Gf>}/A  
{ (t&`m[>K  
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try{ Bc
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URL url = new URL(sURL); 1TA!9cz0Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }y
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httpConnection.setRequestProperty("User-Agent","NetFox"); wTR?8$  
String sProperty = "bytes="+nStartPos+"-"; ?P|
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httpConnection.setRequestProperty("RANGE",sProperty); Jpp-3i.F#  
Utility.log(sProperty); [#\OCdb*3  
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InputStream input = httpConnection.getInputStream(); (JdheCq!x  
//logResponseHead(httpConnection); S?i^ ~  
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byte[] b = new byte[1024]; ^)Y3V-@t  
int nRead; Si~wig2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >m%TUQ#%  
{ S{2;PaK  
nStartPos += fileAccessI.write(b,0,nRead); /o6ido  
//if(nThreadID == 1) 5z3WRg
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;}S_PnwC@  
} DH_~,tK9  
B/lIn'=  
# Dgkl  
Utility.log("Thread " + nThreadID + " is over!"); fM]nP4K`  
bDownOver = true; x%@M*4
:&  
//nPos = fileAccessI.write (b,0,nRead); U{lf$  
} <x;g9Z>(  
catch(Exception e){e.printStackTrace ();} T$r/XAs  
} OraT$lV)_  
} r/N
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//打印回应的头信息 q\!"FDOl4  
public void logResponseHead(HttpURLConnection con) q2*)e/}H  
{ mGP%"R2X  
for(int i=1;;i++) VY~*QF~P  
{ (?XIhpd  
String header=con.getHeaderFieldKey(i); U$a)lcJd  
if(header!=null) u}R|q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Z9% u,Cb  
Utility.log(header+" : "+con.getHeaderField(header)); 13 JG[,w  
else leizjL\P  
break; u\xrC\Ka  
} ;*Y+.?>a  
} g_tEUaiK  
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public void splitterStop() A9DF
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{ ?_S);  
bStop = true; 'X&"(M  
} u5U^}<}y}  
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} V~o'L#a  
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/* 0_^3 |n  
**FileAccess.java yg|yoL'g  
*//文件访问(定位，写) yMgS0  
package NetFox; ;uZq_^?:9&  
import java.io.*; 9dp4&&Z+F  
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public class FileAccessI implements Serializable{ |w_l~xYV)  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1Sns$t%b  
RandomAccessFile oSavedFile; +y-3tcI)  
long nPos; G&6`?1k  
uAk>VPuuZ  
1':};}dCJ  
public FileAccessI() throws IOException %|2x7@&s  
{ U?:?NC=1{  
this("",0); J}@.f-W\j  
} &"yoJ<L  
FA%BzU5^  
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public FileAccessI(String sName,long nPos) throws IOException ;Q5o38(  
{ #V[Os!ns  
oSavedFile = new RandomAccessFile(sName,"rw"); 8)f/H&)>8  
this.nPos = nPos; P!&yYR\  
oSavedFile.seek(nPos); W{}M${6&  
} ICWHEot  
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V
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public synchronized int write(byte[] b,int nStart,int nLen) &D7Mv5i0@  
{ r8_MIGM'  
int n = -1; ,nniSG((3  
try{ *>lXCx  
oSavedFile.write(b,nStart,nLen); yW}x  
n = nLen; a7z%)i;Z  
} #J$z0%P  
catch(IOException e) 2d OUY $4  
{ O3p<7`K<4  
e.printStackTrace (); kh"APxQ79  
} y(**F8>?xE  
#<w2xR]:  
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return n; m]VOw)mBF  
} t1o_x}z4.  
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} MnW"ksH  
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/* RWGAxq`9f  
**SiteInfoBean.java 7I:<i$)V  
*/ TzV~I\a|  
package NetFox; QLH6Nmk  
XpP}(A@G  
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public class SiteInfoBean { KC-@2,c9V  
idZ]d6  
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private String sSiteURL; //Site's URL 1F[W~@jW  
private String sFilePath; //Saved File's Path !4+@b s  
private String sFileName; //Saved File's Name ]7%+SH,RdD  
private int nSplitter; //Count of Splited Downloading File 'u%SI]*;>  
+?C7(-U>  
jbu+>  
public SiteInfoBean() ia%U;M  
{//nSplitter的缺省值为5 frbeCBP&)  
//default value of nSplitter is 5 {mB &xz:b  
this("","","",5); 9Ui|8e~=  
} wB%;O`Oh  
(!diPwcv  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) A}0u-W  
{ PA${<wyBR_  
sSiteURL= sURL; qyY]: (8  
sFilePath = sPath; #}nDX4jI  
sFileName = sName; M{`uI8vD  
this.nSplitter = nSpiltter;  LhtA]z,m  
+bc
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.OvH<%g!.  
} 2[Bw+<YA`  
%`^{Hh`  
hkvymHaG  
public String getSSiteURL() rPoq~p
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{ _{0
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return sSiteURL; Zl=IZ?F   
} PQ4)k
VT  
9':MD0P/M  
qM0Df0$?x  
public void setSSiteURL(String value) ]*pro|  
{ kk7M$)>d  
sSiteURL = value; PRyzUG&  
} `:;fc  
Qon>[<]B  
Q`[J3-Q*{  
public String getSFilePath() A$X
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{ sWX\/Iyy2p  
return sFilePath; DzG$\%G2R}  
} Vi\kB
%  
3v:c'R0  
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public void setSFilePath(String value) C!S(!Z,  
{ e:zuP.R  
sFilePath = value; Jnf@u  
} qb7ur;  
'mU7N<Q$qQ  
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public String getSFileName() >r5s>A[YC  
{ xC.Tipn>  
return sFileName; szU_,.\  
} E|hW{oX3  
Qwu~{tf+'  
vHxLn/  
public void setSFileName(String value) |
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{ !Di*y$`}b  
sFileName = value; cuo'V*nWQ  
} 3eJ"7sftW
 
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public int getNSplitter() 29AWg(9?aS  
{ qQx5n  
return nSplitter; Ym/y2B(  
} {/PiX1mn  
Z^SF $+UN  
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public void setNSplitter(int nCount) X*Cvh|  
{ c6f[^Q%#j  
nSplitter = nCount; w@"l0gm+u[  
} l!YjDm{E  
} .0f6b  
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/* %$H~  
**Utility.java Z/w "zCd  
*/ :bV1M5  
package NetFox; /$,~|X;&  
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public class Utility { @Ap~Wok  
&S|%>C{P.w  
9 9S-P}xd  
public Utility() "J
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{ l!^+Xeg~  
{Mx3G*hr
 
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} OD\F*Ry~  
&]mZp&  
//线程睡眠 ~Dz
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public static void sleep(int nSecond) F1aI4H<(T  
{ ?YTngIa  
try{ Yl!~w:O!o  
Thread.sleep(nSecond); 6I`Lszs  
} DsZBhjCB  
catch(Exception e) FG[YH5  
{ b ?-VZA:  
e.printStackTrace (); nNJMQb'K  
} [TFd|ywn  
} cXY;Tw45  
quEP"  
//日志 d5O_~xf&  
public static void log(String sMsg) <B%s9Zy  
{ ExDv7St1(k  
System.err.println(sMsg); sa26u`?  
} >PBP:s1f4>  
h &R1"  
C%l+<wpXO  
public static void log(int sMsg) a\BV%'Zqg  
{ B<p -.tv  
System.err.println(sMsg); Z+G.v=2q<  
} f,_EPh>  
} WK<:(vu.  
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,4&?`Q  
/* c4'k-\JvT  
**TestMethod.java X>W2aDuEZ  
*/  ~;#OQ[  
package NetFox; !iO%?nW;  
<HC5YA)4  
O^+H:Y|  
public class TestMethod { `,O#r0m  
8o SNnT  
} qf=5v  
public TestMethod() +nj 2  
{ ///xx/weblogic60b2_win.exe +"i|)yUYy}  
try{ 
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); sBLf(Q,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @*VfG CQ(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <V~B8C!)  
fileFetch.start(); 'fGB#uBt  
} 8NJxtT~0c~  
catch(Exception e){e.printStackTrace ();} aA|<W g  
,
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} P~H
?[ ;  
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; m]KKB  
public static void main(String[] args) 2.>WR
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{ [K=M;$iQ  
new TestMethod(); R'udC}  
} D
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} )#H&lH  
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