http断点续传简单实现（java)

/* O<*l"fw3  
**SiteFileFetch.java /Ezx'h3Q  
*/ 2\b 2W_  
package NetFox; x;F^7c1  
import java.io.*; B#A .-nb  
import java.net.*; ?Nbc#0pb7  
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public class SiteFileFetch extends Thread { !vrduOB  
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SiteInfoBean siteInfoBean = null; //文件信息Bean D*nNu]|j  
long[] nStartPos; //开始位置 .uoQ@3  
long[] nEndPos; //结束位置 ,/bSa/x`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 bG|aQ2HW  
long nFileLength; //文件长度 5z T~/6-(  
boolean bFirst = true; //是否第一次取文件 ]Qu.-F#g  
boolean bStop = false; //停止标志 "mk4O4dF  
File tmpFile; //文件下载的临时信息 tM% f#O  
DataOutputStream output; //输出到文件的输出流 TJ5g?#Wul  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^zfO=XN  
public SiteFileFetch(SiteInfoBean bean) throws IOException l%f&vOcd  
{ G\;a_]Q  
siteInfoBean = bean; ytDp 4x<W)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %k"qpu  
if(tmpFile.exists ()) 3IlflXb  
{ rw|;?a0  
bFirst = false; h1A/:/_M6  
read_nPos(); pBbfU2p  
} $:4*?8K2  
else 2#XYR>[  
{ (C&Lpt_  
nStartPos = new long[bean.getNSplitter()]; %XQ!>BeE  
nEndPos = new long[bean.getNSplitter()]; QAk.~ob  
} IAlX^6s*  
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} iC.k8r+~  
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@[=K`n:n_  
public void run() (v@)nv]U  
{ ,$,c<M  
//获得文件长度 KJs/4oR;  
//分割文件 q!OB?0
3n  
//实例FileSplitterFetch fPA5]a9  
//启动FileSplitterFetch线程 2VZdtz  
//等待子线程返回 8M~^/
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try{ y$Y*%D^w  
if(bFirst) ov9+6'zya  
{ "R!)"B==  
nFileLength = getFileSize(); 'f "KV|  
if(nFileLength == -1) &yabxl_  
{ }
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System.err.println("File Length is not known!"); C3hQT8~  
} >Av[`1a2F  
else if(nFileLength == -2) p-S&Wq  
{ C 7a$>#%  
System.err.println("File is not access!"); G9YfJ?I  
} 01_*^iCf5  
else CD"D^\z  
{ 89kxRH\IhG  
for(int i=0;i<nStartPos.length;i++) ;Pd nE~  
{ &hSABtr}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;UnJrP-if  
} W74Y.zQ  
for(int i=0;i<nEndPos.length-1;i++) Osk'zFiL<  
{ `Vf k
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nEndPos = nStartPos[i+1]; gx55.}  
} xl]1{$1M  
nEndPos[nEndPos.length-1] = nFileLength; aQTISX;  
} dsiQ~ [   
} ;WqWD
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Nj^:8]D)0  
//启动子线程 m8:9Uv  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *pP&$!bH%  
for(int i=0;i<nStartPos.length;i++) 3%0ShMFP@  
{ {~y,.[Ga  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %RS~>pK1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <|kS`y  
nStartPos,nEndPos,i); 7%0V?+]P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |l#<vw wE  
fileSplitterFetch.start(); \$B%TY  
} qrw"z iW  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ih[!v"bv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $.0l%
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Pqtk1=U  
nEndPos = " + nFileLength); xk/osbKn  
// fileSplitterFetch[nPos.length-1].start(); 3&tJD  
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1v M'yr$  
//等待子线程结束 5X1z^(   
//int count = 0; u &qFE=5:  
//是否结束while循环 u
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boolean breakWhile = false; V0O6\)/.  
@}oY6cW;B*  
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while(!bStop) 9()d7Y#d/`  
{ G
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write_nPos(); x[dR5  
Utility.sleep(500); +k<0:Fi  
breakWhile = true; Zai:?%^  
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for(int i=0;i<nStartPos.length;i++) Q&k1' nT5  
{ -L6YLe%w  
if(!fileSplitterFetch.bDownOver) N0POyd/rL  
{ D_D76  
breakWhile = false; !*1Kjg3  
break; >DSD1i+
N  
} d&x #9ka  
} ,ej89  
if(breakWhile)  d H ;  
break; y~Ts9AE  
"R5! VV  
>K@Y8J+e#  
//count++; lB< kf1[  
//if(count>4) N\nxo0sl  
// siteStop(); 7+2DsZ^6MW  
} KM:k<pvi  
8TH fFL  
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System.err.println("文件下载结束！"); j-%@A`j;  
} q,%lG$0v  
catch(Exception e){e.printStackTrace ();} g-8D1.U  
} $uj3W<iw3E  
B(t`$mC  
AC}[Qp!  
//获得文件长度 N, SbJ Z  
public long getFileSize() M8y:FDX  
{ pj9*$.{  
int nFileLength = -1; ] i:WP2  
try{ DPg\y".4Y&  
URL url = new URL(siteInfoBean.getSSiteURL()); WV?3DzeR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); aJ3.D  
httpConnection.setRequestProperty("User-Agent","NetFox"); }c?W|#y`.o  
*2^+QKDG  
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int responseCode=httpConnection.getResponseCode(); 5oTj^W8M(  
if(responseCode>=400) E},^,65  
{ h( V:-D  
processErrorCode(responseCode); 3I.0jA#T&/  
return -2; //-2 represent access is error !V O^oD7  
} 'L5ih|$>  
oQL$X3S  
s.IYPH|pn  
String sHeader; G4jyi&]  
( C~
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=#so
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for(int i=1;;i++) SsBiCctn  
{ G5!J9@Yi  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :v Do{My^1  
//Utility.log(in.readLine()); dc=}c/6x  
sHeader=httpConnection.getHeaderFieldKey(i); x;@wtd*QB  
if(sHeader!=null) !l|fzS8g  
{ *m6h(8(7Z  
if(sHeader.equals("Content-Length")) IZSJ+KO
 
{ AA &>6JB{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N% !TFQf  
break; jxdX
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} vhE^jS<Tg  
} u5O`
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else =pnMV"'9  
break; =~P)7D6  
} k/,7FDO?m  
} (,XbxDfM  
catch(IOException e){e.printStackTrace ();} |6o!]~&e$1  
catch(Exception e){e.printStackTrace ();} kesuM3  
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Utility.log(nFileLength);
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return nFileLength; YwU[kr-i  
} M"s+k  
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EN/r{Cm$B  
//保存下载信息（文件指针位置） pQCocy  
private void write_nPos() PR3&LI;B*  
{ PdqyNn=  
try{ OVUJiBp  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vJ9IDc|[  
output.writeInt(nStartPos.length); 77H"=  
for(int i=0;i<nStartPos.length;i++) n%K^G4k^  
{ rGmxK|R  
// output.writeLong(nPos); rr^?9M*{V  
output.writeLong(fileSplitterFetch.nStartPos); dGG8k&  
output.writeLong(fileSplitterFetch.nEndPos); ]Ei*I}  
}
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output.close(); T8NDS7&?  
} ddzMwucjp  
catch(IOException e){e.printStackTrace ();} `DS7J\c$  
catch(Exception e){e.printStackTrace ();}  %X**(  
} FjV)QP H  
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//读取保存的下载信息（文件指针位置） @ D.MpM}~  
private void read_nPos() c|s7cG$+-  
{ w`_"R6  
try{ E(!b_C&
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3W3)%[ 5  
int nCount = input.readInt(); f-`C1|\w  
nStartPos = new long[nCount]; uJSzz:\  
nEndPos = new long[nCount]; HlOn=>)<  
for(int i=0;i<nStartPos.length;i++) U(:Di]>{  
{ 1b,MJ~g$  
nStartPos = input.readLong(); 2#Du5d  
nEndPos = input.readLong(); S0w:R:q}L  
} !:3X{)4  
input.close(); cD ?'lB-  
} \rM5@ Vf  
catch(IOException e){e.printStackTrace ();} ows3%  
catch(Exception e){e.printStackTrace ();} ;5tQV%V^Q  
} 61Wh %8-  
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private void processErrorCode(int nErrorCode) jidRh}>a=  
{ O"~CZh,:r}  
System.err.println("Error Code : " + nErrorCode); u$<>8aMei  
} 9>r@wK'Pn  
a: 2ezxP  
_6.Y3+7I  
//停止文件下载 N(`XqeC*  
public void siteStop() o&MOcy D  
{ *nSKIDw  
bStop = true; uc Ph*M  
for(int i=0;i<nStartPos.length;i++) B &e'n
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fileSplitterFetch.splitterStop(); MW|R)gt  
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9  
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} c0Yc~&RF  
} 9`td_qh  
//负责部分文件的抓取 )Wy:I_F351  
**FileSplitterFetch.java 5;X r0f  
*/ |ZG0E  
package NetFox; j8W<iy  
0M!GoqaA  
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import java.io.*; `r]C%Y4?  
import java.net.*; =Q#d0Q  
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public class FileSplitterFetch extends Thread { {a0yHy$H  
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String sURL; //File URL sAS[wcOQ  
long nStartPos; //File Snippet Start Position o>HU4
O}  
long nEndPos; //File Snippet End Position >%LY0(hY3  
int nThreadID; //Thread's ID rgF4 W8  
boolean bDownOver = false; //Downing is over h_5CWQSi  
boolean bStop = false; //Stop identical O!P7Wu  
FileAccessI fileAccessI = null; //File Access interface q!{>Nlk  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException M9~6ry-_  
{ 1
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this.sURL = sURL; ;tC$O~X  
this.nStartPos = nStart; JHa\"h  
this.nEndPos = nEnd; V[0 ZNT&  
nThreadID = id; F *1w8+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |t~*!0>3  
} x/0loW?q^  
t==\D?Rt  
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public void run() VIg6'  
{ L*cP8v4  
while(nStartPos < nEndPos && !bStop) 8^67,I-c  
{

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 'Pxq>Os  
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try{ -""(>$b2  
URL url = new URL(sURL); Py#TXzEcC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9Dp0Pi?29  
httpConnection.setRequestProperty("User-Agent","NetFox"); SqZ .}s  
String sProperty = "bytes="+nStartPos+"-"; &gcZ4gpH  
httpConnection.setRequestProperty("RANGE",sProperty); fr`Q 5!0  
Utility.log(sProperty); gv){&=9/  
_&r19pY  
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InputStream input = httpConnection.getInputStream(); ]QGo(+  
//logResponseHead(httpConnection); \1hQ7:f;\  
6!SW]#sD  
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byte[] b = new byte[1024]; f)mOeD*u|  
int nRead; 0Oa&vx  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "^)GnK +-  
{ b[J0+l\!"  
nStartPos += fileAccessI.write(b,0,nRead); MT6"b  
//if(nThreadID == 1) -Jt36|O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); biV NZdA  
} gwr?(:?  
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i,t!17M:  
Utility.log("Thread " + nThreadID + " is over!"); Ns]$+|  
bDownOver = true; jig3M N  
//nPos = fileAccessI.write (b,0,nRead); bd H+M?k  
} I%NeCd  
catch(Exception e){e.printStackTrace ();} SgssNv  
} )Y6\"-M[  
} {yDQncq'^  
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lOM8%{.'_x  
//打印回应的头信息 eAStpG"*  
public void logResponseHead(HttpURLConnection con) .osG"cS  
{ _-rC]iQJ55  
for(int i=1;;i++) DF UTQ:N  
{ YRMe<upo  
String header=con.getHeaderFieldKey(i); jib pZ)  
if(header!=null) &xZSM,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )+ 'r-AF*  
Utility.log(header+" : "+con.getHeaderField(header)); UyFC\vQ  
else 4sW'pH  
break; u%lUi2P2E  
} kP'm$+1or  
} p:W{c/tV  
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public void splitterStop() *Ms&WYN-  
{ I;n<) >  
bStop = true; 5{#s<%b.  
} s6r(\L_Im  
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} 9tb-;|  
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)FPn_p#3]  
/* q
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**FileAccess.java 6}V
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*//文件访问(定位，写) e=aU9v L  
package NetFox; |KVVPXtq%C  
import java.io.*; <sw=:HU  
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public class FileAccessI implements Serializable{ Sk)lT^by  
(&v,3>3]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }!?RB v'W  
RandomAccessFile oSavedFile; *_7/'0E(3  
long nPos; o';/$xrH  
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@WJ\W`P  
public FileAccessI() throws IOException \Rb:t}  
{ ^do6?e`?-  
this("",0); >#'?}@FWQN  
} ^b}Wl0Fn  
Od^Sr4C  
-Sn'${2  
public FileAccessI(String sName,long nPos) throws IOException LAY
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{ _*n `*"  
oSavedFile = new RandomAccessFile(sName,"rw"); fms(_Q:R?  
this.nPos = nPos; wOCAGEg  
oSavedFile.seek(nPos); gFrNk Uqp  
} 0TSB<,9a[  
#ti%hm  
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public synchronized int write(byte[] b,int nStart,int nLen) t%J1(H  
{ }}ic{931  
int n = -1; */_'pt  
try{ ^\kH^  
oSavedFile.write(b,nStart,nLen); Jz3,vVfQ:  
n = nLen; !s?SI=B8  
} FvYciU!  
catch(IOException e) as('ZD.9  
{ -|f0;Fl  
e.printStackTrace (); /AyxkXq  
} s$?LMfT  
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return n; "^!y>]j#A  
} *,%$l+\h  
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} zx,9x*g  
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/* :=TIq  
**SiteInfoBean.java Pr(@&:v:  
*/ { PJ>gX$  
package NetFox; Gk/cP`  
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{:#nrD"  
public class SiteInfoBean { H0sTL#/L\  
E`V\/`5D  
;,e16^\' &  
private String sSiteURL; //Site's URL B /w&Lo  
private String sFilePath; //Saved File's Path "tl$JbRTY  
private String sFileName; //Saved File's Name t*-cX  
private int nSplitter; //Count of Splited Downloading File x#N_h0[i  
yjMN>L'  
deVnAu =  
public SiteInfoBean() kd\Hj~*  
{//nSplitter的缺省值为5 l'aCpzf  
//default value of nSplitter is 5 w=n(2M56C  
this("","","",5); J 7G-qF\  
} tq3Rc}  
%>_6&A{K,d  
@\XeRx;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ie(.T2K  
{ _MLf58  
sSiteURL= sURL; "om7 :d  
sFilePath = sPath; 3+s$K(%I  
sFileName = sName; pMy:h   
this.nSplitter = nSpiltter;
"y&`,s5}  
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} /
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public String getSSiteURL() 8.8t$  
{ # Q,EL73;  
return sSiteURL; Rz|@BxB>n  
} gGUKB2)  
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public void setSSiteURL(String value) .(.
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{ !|i #g$  
sSiteURL = value; ;H.V-~:P)  
} 
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public String getSFilePath() _8 |X820  
{ i,a"5DR8  
return sFilePath; Iia.`"S  
} *|Er;Thw  
.#$2,"8  
}aR}ZzK/v  
public void setSFilePath(String value)  0.0-rd>  
{ VZI!rFac  
sFilePath = value; 3B 'j?+A  
} fz:(mZ%  
t(-,mw  
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public String getSFileName() 0 }od Q#  
{ QAp]cE1ew  
return sFileName; xlu4  
} n+hL/aQ+  
\|HNFxT`  
.6a
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public void setSFileName(String value) "O<ETHd0  
{ 2~?E'  
sFileName = value; PWiUW{7z  
} JHvev,#4  
Yg3nT:K_Y&  
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public int getNSplitter() y^`JWs,  
{ ?SElJ?Z  
return nSplitter;
`HkNO@N[  
} 3u$1W@T(  
/B~[,ES@1  
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public void setNSplitter(int nCount) ,r;xH}tbi  
{ 6{HCF-cQd  
nSplitter = nCount; XDPgl=~  
} (H !iK,R  
} l[ $bn!_e  
w,FPL&{  
&4S2fWx  
/* L}Y.xi  
**Utility.java !Vw
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*/ )j>U4a  
package NetFox; pF8 #H~  
%}VH5s9\  
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public class Utility { 5HV+7zU5  
,_RNZ sa;&  
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public Utility() Dz6xx?  
{ mQ"uG?NE  
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} e@W+ehx"  
M lR~`B}m  
//线程睡眠 /z*Z+OT2  
public static void sleep(int nSecond) O.(2  
{ +K`A2&F9  
try{ ~s'tr&+  
Thread.sleep(nSecond); 4A!]kj5T  
} jTcv&`fAz  
catch(Exception e) ZDW=>}~_y  
{ ;x/eb g  
e.printStackTrace (); <4q H0<  
} V9BW@G@9  
} <SI|)M,, 3  
V+O,y9  
//日志 6~x'~T  
public static void log(String sMsg) 2]]v|Z2M4  
{ P$#:$U@  
System.err.println(sMsg); PVBz~rG  
} ~E7IU<B  
=,#--1R7g  
nJ2x;';lA  
public static void log(int sMsg) PU/<7P*  
{ 96(Mu% l  
System.err.println(sMsg); 6^[4.D  
} L!If~6oD(  
} ZhA_d#qH  
sjg`4^!wDD  
| :-i[G?n  
/* F`QViZ'n>#  
**TestMethod.java _y^r==  
*/ 5o dT\>Sn  
package NetFox; Ec@n<KK#  
2+ cs^M3  
Szgo@x$^  
public class TestMethod { wwB3m&  
Lz'VQO1U=  
-{xk&EB^$5  
public TestMethod() Nhjq.&  
{ ///xx/weblogic60b2_win.exe bItcF$#!!!  
try{ VWvSt C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); LZRg%3.E
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xf]K  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]$@D=g,r  
fileFetch.start(); w#|L8VAh  
} `.W2t5Y  
catch(Exception e){e.printStackTrace ();} `x`[hJ?i  
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} P9 <U+\z  
&3[oM)-V  
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public static void main(String[] args) 3N2dV6u  
{ :hX[8u  
new TestMethod(); qq| 5[I.?  
} ukW&\  
} FQDf?d5  
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