http断点续传简单实现（java)

/* +)jll#}?  
**SiteFileFetch.java UlE%\L0GD&  
*/ EaO@I.[  
package NetFox; DdgiY9a.  
import java.io.*; 
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import java.net.*; #lLUBJ#:  
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public class SiteFileFetch extends Thread { &P|[YP37_  
x [FLV8`b|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean [
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long[] nStartPos; //开始位置 A>yU0\A  
long[] nEndPos; //结束位置 l:!L+t*}6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ilL0=[2  
long nFileLength; //文件长度 !rM~  
boolean bFirst = true; //是否第一次取文件 1jl!VU6  
boolean bStop = false; //停止标志 E6A"Xo  
File tmpFile; //文件下载的临时信息 `S@TiD*  
DataOutputStream output; //输出到文件的输出流 )O~[4xV~  
.z`70ot?  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） GrL{q;IO  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^QRg9s,T<  
{ xLz=)k[''  
siteInfoBean = bean; -[V-f> :  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^[tE^(|T  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p?:5U[KM  
if(tmpFile.exists ()) 5:h[%3'bB  
{ cqNK`3:.j  
bFirst = false; ((k"*f2%  
read_nPos(); -Ks>s  
} w6% Q"%rp  
else m.e]tTe  
{ f V. c6  
nStartPos = new long[bean.getNSplitter()]; !.]JiT'o  
nEndPos = new long[bean.getNSplitter()]; 7z{w
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} q!5:M\  
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} az(<<2=  
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public void run() Nz,yd%ua  
{ R2~Tr$:  
//获得文件长度 iEr,ly  
//分割文件 ` R6`"hx$  
//实例FileSplitterFetch \2i7\U  
//启动FileSplitterFetch线程 I0)`tQ+  
//等待子线程返回 w )R5P[b  
try{ JbMTULA  
if(bFirst) _/s"VYFZ  
{ i6`"e[aT[o  
nFileLength = getFileSize(); @p+;iS1}  
if(nFileLength == -1) |7s2xRc  
{ bmfM_oz  
System.err.println("File Length is not known!"); V8?}I)#(7  
} K9lgDk"i  
else if(nFileLength == -2) g7*)|FOb  
{ yw3"jdcl  
System.err.println("File is not access!"); WlMcEje  
} |"3<\$[  
else 7;"0:eX  
{ 11[lc2  
for(int i=0;i<nStartPos.length;i++) :gh[BeqQ)  
{ ?{{w[U6NE  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |cPHl+$nh.  
} %BqaVOKJ"f  
for(int i=0;i<nEndPos.length-1;i++) k9^Hmhjw  
{ IHl q27O  
nEndPos = nStartPos[i+1]; ^OR0Vp>L  
} 5'~_d@M  
nEndPos[nEndPos.length-1] = nFileLength; _kj]vbG^;  
} SUncQJJ0S*  
} RK>Pe3<  
#WpkL]g2+%  
WNjwv/  
//启动子线程 > VG  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Ccf/hA#mb  
for(int i=0;i<nStartPos.length;i++) +eM${JyXH  
{ XpIiJry!6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a&y^Ps6=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c7Z4u|G  
nStartPos,nEndPos,i); Zp_(vOc  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;?-AFd\i
 
fileSplitterFetch.start(); o`?rj!\  
} woYD &Oml  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ie}OZM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5,RUPaE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", T(4d5 fY  
nEndPos = " + nFileLength); w2)Ro:G  
// fileSplitterFetch[nPos.length-1].start(); mo0\t#jA  
o\AnM5  
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//等待子线程结束 s[1ao"sZ^  
//int count = 0; lo1Ui`V  
//是否结束while循环
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boolean breakWhile = false; 5\-uo&#  
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^[L(kHOGzk  
while(!bStop) J~Xv R  
{ ]$ew 5%  
write_nPos(); [uq>b|`RG  
Utility.sleep(500); pMc6p0  
breakWhile = true; fCl}eXg6w  
]Z JoC!u  
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for(int i=0;i<nStartPos.length;i++) (JhX:1  
{ c}x1-d8  
if(!fileSplitterFetch.bDownOver) X'9.fKp  
{ X|M!Nt0'  
breakWhile = false; E-MPFL  
break; +jN}d=N-  
} !XA3G`}p6s  
} 7p&jSOY  
if(breakWhile) XX;4A  
break; 30Yis_l2h  
.p`4>XA  
g8),$:Uw  
//count++; )^h6'h`  
//if(count>4) cH]tZ$E`  
// siteStop(); dn6B43w  
} KWwtL"3  
W+XWS,(  
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System.err.println("文件下载结束！"); 3:%k pnO  
} jjpYg  
catch(Exception e){e.printStackTrace ();} *
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} 6Z/`p~e  
;`9f<d#\  
1C[9}}  
//获得文件长度 y!e]bvN  
public long getFileSize() }fpya2Xt  
{ fGgt[f[  
int nFileLength = -1; ;?6vKpj;  
try{ 4p_C+4  
URL url = new URL(siteInfoBean.getSSiteURL()); &[.5@sv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y>{:[L9*  
httpConnection.setRequestProperty("User-Agent","NetFox"); :fRXLe1=  
qZoDeN-CC  
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int responseCode=httpConnection.getResponseCode(); b
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if(responseCode>=400) p:,Y6[gMo  
{ ~Eut_d  
processErrorCode(responseCode); ^S#;  
return -2; //-2 represent access is error yTaMlT|  
} -H1=N  
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String sHeader; @|!4X(2  
|J`EM7qMK  
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for(int i=1;;i++) :-&|QVH  
{ -"(*'hD  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r^9l/H~$  
//Utility.log(in.readLine()); 4.6$m  
sHeader=httpConnection.getHeaderFieldKey(i); f*ZU a  
if(sHeader!=null) Z1Qz LvWs  
{ 1CtUf7 `/Q  
if(sHeader.equals("Content-Length")) ^({)t  
{ c=\tf~}^Ms  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); T.q2tC[bR  
break; b`0tfXzS5  
} Nk~}aj  
} ` ]|X_!J-  
else UuG%5
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break; F[qXIL)  
} t2&kGf"  
} :WhJDx`j  
catch(IOException e){e.printStackTrace ();} sW^M  ]  
catch(Exception e){e.printStackTrace ();} &K[*vyD  
2:+8]b3i  
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Utility.log(nFileLength); xh6(~'$  
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return nFileLength; h!"2Ux3!x  
} >T$0*7wF  

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//保存下载信息（文件指针位置） s"(RdJ-,  
private void write_nPos() *k$[/{S1-  
{ D)*  
try{ O5dS$[`j\p  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~z[`G#dU  
output.writeInt(nStartPos.length); /i+z#q5'  
for(int i=0;i<nStartPos.length;i++) Q @}$b(b  
{ 0'q4=!l  
// output.writeLong(nPos); H7O~So*N5  
output.writeLong(fileSplitterFetch.nStartPos); =4ygbk  
output.writeLong(fileSplitterFetch.nEndPos); M!mL/*G@YE  
} AbU`wr/h 4  
output.close(); $0*sjXV  
} F?L]D
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catch(IOException e){e.printStackTrace ();} jKSj);  
catch(Exception e){e.printStackTrace ();} , 
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} _h%Jf{nu  
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//读取保存的下载信息（文件指针位置） !_glZ*t
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private void read_nPos() Q+CJd>B  
{ ; :e7Z^\/k  
try{ ! FcGa  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); KbJ6U75|f  
int nCount = input.readInt(); ^0,}y]5p  
nStartPos = new long[nCount]; aRd~T6I  
nEndPos = new long[nCount]; 6]4~]!  
for(int i=0;i<nStartPos.length;i++) +cpb!YEAb
 
{ 1nVQYqT_  
nStartPos = input.readLong(); 2g(_Kdj*{  
nEndPos = input.readLong(); qLR;:$]Q&8  
} +in)(a.  
input.close(); ?pL|eS7  
} tX*@r  
catch(IOException e){e.printStackTrace ();} O7.V>7Y9H  
catch(Exception e){e.printStackTrace ();} UlXm4\@  
} 9~p;iiKGG  
EPo)7<|>  
ZbRRDXk!  
private void processErrorCode(int nErrorCode) )1<0c@g=  
{ PW*Vfjf4  
System.err.println("Error Code : " + nErrorCode); x;ik   
} K'OG-fn;  
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wGHft`Z  
//停止文件下载 Q\oa<R D5  
public void siteStop() ~z^l~Vyg?  
{ |N,^*xP(6  
bStop = true; 4+olyBht  
for(int i=0;i<nStartPos.length;i++) pEB3qGA  
fileSplitterFetch.splitterStop(); 8X;?fjl`"  
!~^2Mu(X  
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} N2h5@*1Y  
} "|\hTRQ  
//负责部分文件的抓取 3Vu}D(PJ  
**FileSplitterFetch.java >=k7#av  
*/ a%q,P @8  
package NetFox; %p7 ?\>  
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import java.io.*; U$:^^Zt`B  
import java.net.*; [*%lm9 x  
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public class FileSplitterFetch extends Thread { <I,4Kc!  
<3Ftq=  
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String sURL; //File URL ~B<\#oO  
long nStartPos; //File Snippet Start Position 4vg,g(qi<  
long nEndPos; //File Snippet End Position O"9t,B>=i  
int nThreadID; //Thread's ID zJ`u>:*$  
boolean bDownOver = false; //Downing is over ,7nu;fOT[  
boolean bStop = false; //Stop identical (nqhX<T>  
FileAccessI fileAccessI = null; //File Access interface jMT[+f  
r$<!?Z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0GMb?/
  
{ /cS8@)e4  
this.sURL = sURL; \mF-L,yu  
this.nStartPos = nStart; <XL%*  
this.nEndPos = nEnd; 6 `6I<OJ\  
nThreadID = id; Z
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 /
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} mtUiO p  
[_N1 .}e  
LM<*VhX  
public void run() V7$ m.P#uM  
{ Yjg$o:M  
while(nStartPos < nEndPos && !bStop) 3P_.SF  
{ 1@Ba7>%'  
Hc/7x).  
e`Yj}i*bx]  
try{ h!B{7J  
URL url = new URL(sURL); -O})Y>=}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $GoS?\G  
httpConnection.setRequestProperty("User-Agent","NetFox"); j,rc9  
String sProperty = "bytes="+nStartPos+"-"; 8;M,l2pmR{  
httpConnection.setRequestProperty("RANGE",sProperty); \t{iyUx
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Utility.log(sProperty); Jq1oQu|rs  
6@aH2+4+  
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InputStream input = httpConnection.getInputStream(); x.t<@y~  
//logResponseHead(httpConnection); ;apLMMsWC  
g.\b@0Uy'  
AB $N`+&
 
byte[] b = new byte[1024]; (~@.9&cBD  
int nRead;
S1k*"><  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q_T,=y  
{ d 6Y9D=O  
nStartPos += fileAccessI.write(b,0,nRead); ['QhC({  
//if(nThreadID == 1) $y;w
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); II^Rp],>  
} ~U+<
JC Z  
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<mX5VGY9^  
Utility.log("Thread " + nThreadID + " is over!"); J rK{MhO  
bDownOver = true; dC<%D'L*  
//nPos = fileAccessI.write (b,0,nRead); h5{//0 y  
} s?<FS@k  
catch(Exception e){e.printStackTrace ();} 58?WO}  
} 28JVW3&)  
} *wAX&+);  
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/A5=L<T6F  
//打印回应的头信息 u%L6@M2  
public void logResponseHead(HttpURLConnection con) Wz^;:6F  
{ oD%n}  
for(int i=1;;i++) QeY+i
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{ 9f['T
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String header=con.getHeaderFieldKey(i); v~RxtTu  
if(header!=null) u
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); :qS~"@?<  
Utility.log(header+" : "+con.getHeaderField(header)); Qc33CA  
else yO-2.2h  
break; (muJ-~CJk  
} '+_-r'2  
} "P.sKhuo  
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public void splitterStop() [1~3\-Y  
{ %B&O+~  
bStop = true; `-nSH)GBM  
} bSM|"  
{? yRO]  
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} ZyDf@(z`  
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/* bO6z;
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**FileAccess.java x~l"'qsK  
*//文件访问(定位，写) \>T1&JT  
package NetFox; 1`II%mf[  
import java.io.*; 8<Nz34Y  
JAW7Y:XB  

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public class FileAccessI implements Serializable{ 'Q'-7z-6  
yR F+
 
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B8cg[;e81  
RandomAccessFile oSavedFile; qPN  
long nPos; %to.'R  
57 Vn-  
Jbima>  
public FileAccessI() throws IOException m:EYOe,w  
{ ")boY/ P/w  
this("",0); q89yW)XG  
} a"+VP>4  
b6g9!  
WOYZ  
public FileAccessI(String sName,long nPos) throws IOException |/-# N  
{ AED 9vDE  
oSavedFile = new RandomAccessFile(sName,"rw"); D9(4%^HxV1  
this.nPos = nPos; 9(&$Gwi  
oSavedFile.seek(nPos); ,gP;XRe1  
} .>`7d=KT  
EZQ!~  
q9(O=7O]-  
public synchronized int write(byte[] b,int nStart,int nLen) E?0RR'  
{ _#<l -R`  
int n = -1; *nM.`7g*[  
try{ ~9fTs4U  
oSavedFile.write(b,nStart,nLen); yYC\a7Al4  
n = nLen; DL_M#c`<  
} hHt.No  
catch(IOException e) ;r;>4+zn\  
{ Yk4ah$}%-^  
e.printStackTrace (); xoSBMf  
} (yu0iXZY  
}Ny~.EV5^  
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return n; yC}x6xG  
} g2lv4Tiq-  
)P/~{Ci:T&  
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} [o'}R`5)  
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v|kL7t)}  
/* Q
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**SiteInfoBean.java IetV]Ff6  
*/ Z${@;lgP  
package NetFox; B@3>_};Ct  
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[s!cc:JR
 
public class SiteInfoBean { )o_$AbPt  
87V
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private String sSiteURL; //Site's URL i];@e]   
private String sFilePath; //Saved File's Path 3~0Xe  
private String sFileName; //Saved File's Name 4p&SlJ  
private int nSplitter; //Count of Splited Downloading File nYY'hjZ  
MU_ >+Wnf  
b~G|B
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public SiteInfoBean() BgG+  
{//nSplitter的缺省值为5 0xutG/-&N  
//default value of nSplitter is 5 64!V8&Ay  
this("","","",5); !91<K{#A{  
} ]_)=xF19  
gtP;Qw'  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) l\-(li H  
{ YwM;G g3  
sSiteURL= sURL; E?f*Z{~,  
sFilePath = sPath; qoD M!~  
sFileName = sName; j[1^#kE  
this.nSplitter = nSpiltter; u`X}AKC  
U#_rcu  
t#J #DyY5  
} p&\x*~6u  
[2
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public String getSSiteURL() BUKh5L  
{ !NOvKC!  
return sSiteURL; Y|i!\Ae  
} [+y
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o;:a6D`   
7~q'3 N  
public void setSSiteURL(String value) Y-,1&$&
 
{ 0r\hX6 k  
sSiteURL = value; Ol@ YSkd  
} \+w -{"u$  
V/!8q`lYNJ  
]pA}h.R#-  
public String getSFilePath() !*xQPanL  
{ Ts:pk  
return sFilePath; WS0RvBvb  
} BPKeG0F7  
:
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L``K. DF  
public void setSFilePath(String value) P3YG:*  
{ bsmnh_YRj  
sFilePath = value; B6Tn8@O  
} (iiyptJ  
tL4xHa6v]  
\h"QgHzp  
public String getSFileName() |5,
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{ ,G
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return sFileName; e~weYGK  
} F3a"SKMW  
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7<?v!vQ}-  
public void setSFileName(String value) Hca)5$yL  
{ Pz+8u&~p  
sFileName = value; I|$_[Sw  
} [H)p#x  
\9BIRY`  
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public int getNSplitter() Hp":r%)  
{ NLF{W|X  
return nSplitter; |^@TA
=_  
} o0Hh&:6!M  
L+QEFQ:r5  
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public void setNSplitter(int nCount) 413r3/  
{ >[Q(!Ai  
nSplitter = nCount; femAVx}go  
} aX1|&erI  
} #tBbvs+%  
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y#Ch /Jg?|  
/* i@_|18F]`  
**Utility.java M ~!*PCd5  
*/ (F7!&]8%  
package NetFox; J74nAC%J^  
crC];LMl/  
7z6yn=B  
public class Utility { c{#lKD<7  
82Vxk  
eA_1?j]E3  
public Utility() <  v_?}  
{ 2Sb~tTGz79  
f5/ba9nI  
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} h_d!G+-]  
qx53,^2  
//线程睡眠 Z!|nc.
  
public static void sleep(int nSecond) <H E'5b  
{ Jo h&Ay  
try{ K#";!  
Thread.sleep(nSecond); 88)0Xi|]KP  
} WohK,<Or  
catch(Exception e) .'7o,)pJ<  
{ dmrM %a}W-  
e.printStackTrace (); #ZGWU_l}  
} TiF$',WMv  
} }kXF*cVg  
Khw!+!(H  
//日志 IEeh)aj[  
public static void log(String sMsg) Q:kpaMA1P  
{ %r~TMU2"  
System.err.println(sMsg); hlkf|H  
} E9226  
.Fh5:WN  
8X*6i-j5E  
public static void log(int sMsg) [?Aq#av  
{ ~Cj+6CrT  
System.err.println(sMsg); <6n(a)L1  
} JYKA@sZHe  
} [>?B`1;@  
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I%*o7"  
/* +5)
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**TestMethod.java ;Cyt2]F  
*/ w>VM--  
package NetFox; 3r^i>r8B  
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ycCEXu2F  
public class TestMethod { Te!q(;L`4  
6eK18*j%H  
Fv5@-&y$W  
public TestMethod() XF{}St~(  
{ ///xx/weblogic60b2_win.exe 31YzTbl[H  
try{ )Cyrs~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6]Ppa ~Xwq  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M*+_E8Lh  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ga~rllm;i  
fileFetch.start(); 0V`0="rQ  
} qz(0iZ]Y  
catch(Exception e){e.printStackTrace ();} @oug^]a  
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} 7PP76$  
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xk.\IrB_  
public static void main(String[] args) }3^t,>I=,6  
{ ?OvtR:hC  
new TestMethod(); X )g
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} M_UhFY='  
} OES+BXGX  
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