http断点续传简单实现（java)

/* @Y8/#6KE  
**SiteFileFetch.java w\PCBY=  
*/ XnCrxj  
package NetFox; Js("H  
import java.io.*; ;?`l1:C5)  
import java.net.*; ?5
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public class SiteFileFetch extends Thread { rDvz2
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; Da[jFP  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {#Vck\&  
long[] nStartPos; //开始位置 2*<'=*zaQ  
long[] nEndPos; //结束位置 5/{";k)L+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3jG #<4;J  
long nFileLength; //文件长度 yk<$XNc  
boolean bFirst = true; //是否第一次取文件 PiTe/  
boolean bStop = false; //停止标志 _o-lNt+  
File tmpFile; //文件下载的临时信息 :a#pzEK  
DataOutputStream output; //输出到文件的输出流 u|'}a3  
*w[\(d'T  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） J|D$  
public SiteFileFetch(SiteInfoBean bean) throws IOException ZKT~\l  
{ yavoGk
 
siteInfoBean = bean; V7qc9Gd@I  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3-T}8VsiP  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Es~|:$(N]|  
if(tmpFile.exists ()) `T \"B%  
{ 1; "t8.*%e  
bFirst = false; +#|):aF  
read_nPos(); )f6:{ma  
} <m|\#Jw_V  
else W18I"lHeh  
{ ,& ^vc_}  
nStartPos = new long[bean.getNSplitter()]; xO<
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nEndPos = new long[bean.getNSplitter()]; (3;dtp>Xx  
} .}V&*-e
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} nHB=*Mj DV  
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public void run() .M$}.v  
{ @^)aUOe  
//获得文件长度 xa?#wY b  
//分割文件 jD eNCJ  
//实例FileSplitterFetch ERE1XOe=D  
//启动FileSplitterFetch线程 [v!TQwMU  
//等待子线程返回 u VZouw#  
try{ Rt{`v<  
if(bFirst) 
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{ BIr24N  
nFileLength = getFileSize(); K[XFJ9  
if(nFileLength == -1) =`l).GnN2`  
{ {_]'EK/w  
System.err.println("File Length is not known!"); 5"]t{-PD  
} >,JA=s  
else if(nFileLength == -2) kZ0|wML8  
{ bxS+ R\  
System.err.println("File is not access!"); D3>;X=1  
} j+_pF<$f:  
else 4&+;n[D  
{ B:pIzCP  
for(int i=0;i<nStartPos.length;i++) (xJZeY)-b^  
{ L,XWX8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jb~/>I^1  
} H$/r{gfg^  
for(int i=0;i<nEndPos.length-1;i++) h]#wwJF  
{ 7fOk]Yl[  
nEndPos = nStartPos[i+1]; tv+H4/  
} N~%F/`Z<+  
nEndPos[nEndPos.length-1] = nFileLength; <Y
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} V|h/a\P  
} z>f>B6  
>9S@:?^&q>  
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//启动子线程 Wy'H4Rg8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; a^*@j:[  
for(int i=0;i<nStartPos.length;i++) (v\Cv)OS  
{ B`/cKfg  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a09]5>*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p$5+^x'(  
nStartPos,nEndPos,i); c 4<~?L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K`9ph"(Z  
fileSplitterFetch.start(); NTHy!y<!h  
} Use`E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !*?Ss  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +U%U3tAvs  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H@uCbT  
nEndPos = " + nFileLength); u,d@oF(=  
// fileSplitterFetch[nPos.length-1].start(); zaix_mR  
r`Qzn" H  
`z=I}6){  
//等待子线程结束 Ng6(2
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//int count = 0; \?bp^BrI  
//是否结束while循环 (]Z$mv!  
boolean breakWhile = false; [S}o[v\  
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_%)v9}D  
while(!bStop) %#.HFK  
{ !~{AF|2f  
write_nPos(); .Jt&6N  
Utility.sleep(500); =Of!1TR(  
breakWhile = true; *N0R3da  
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for(int i=0;i<nStartPos.length;i++) Lmy ^/P%  
{ ugM,wT&~Y  
if(!fileSplitterFetch.bDownOver) dz',!|>  
{ WH.5vrY Z  
breakWhile = false; M~/%V NX  
break; 0Wf,SYx`s  
} }Om+,!_d  
} TB]Bl.  
if(breakWhile) r$~w3yN)v  
break; oJF@O:A  
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f!`,!dZgkd  
//count++; 4MVa[0Y  
//if(count>4) `hD\u@5Tw  
// siteStop(); 2VOdI  
} (9N75uCa  
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}ug|&25D  
System.err.println("文件下载结束！"); .TN9N  
} hi>sDU<x  
catch(Exception e){e.printStackTrace ();} <}c`jN!z.  
} <y(uu(c  
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X*2MNx^K~  
//获得文件长度 silTL_$  
public long getFileSize() xGQ958@  
{ MorR&K  
int nFileLength = -1; D?u*^?a2  
try{ .)W'{2J-  
URL url = new URL(siteInfoBean.getSSiteURL()); SC~cryb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _MZqH8  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xj;nh?\u  
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int responseCode=httpConnection.getResponseCode(); z G {1;  
if(responseCode>=400) llbj-9OZL  
{ 93|u. @lEy  
processErrorCode(responseCode); ;4E0%@R  
return -2; //-2 represent access is error q%=`PCty  
} 3A_7R-sQ  
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String sHeader; )#9R()n!  
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for(int i=1;;i++) A*BIudli  
{ I=VPw5"E  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); JJ3(0 +  
//Utility.log(in.readLine()); (m[]A&u  
sHeader=httpConnection.getHeaderFieldKey(i); &L,zh{Mp  
if(sHeader!=null) goi5I(yn^  
{ ,TTt<&c  
if(sHeader.equals("Content-Length")) r>:7)p!|  
{ 8|A*N<h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); O2E6F^.pYw  
break; 8CxC`*L(  
} C7`FM@z  
} 1(`>9t02/?  
else U:eahK  
break; ?d1H]f<M  
} T?W`g>yM  
} 3tMFJ ;*`  
catch(IOException e){e.printStackTrace ();} @x">e][B  
catch(Exception e){e.printStackTrace ();} KaC+x-%K  
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Utility.log(nFileLength); V.kUFTCvf  
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return nFileLength; :]Jwcp  
} #$xiqL  
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//保存下载信息（文件指针位置） &ZgB
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private void write_nPos() 2
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{ |q5R5m
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try{ :Vc+/ZyW  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &[}T41  
output.writeInt(nStartPos.length); n83,MV?-  
for(int i=0;i<nStartPos.length;i++) }E+}\&  
{ >
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// output.writeLong(nPos); yz!j9pJ  
output.writeLong(fileSplitterFetch.nStartPos); IiV:bHUE}0  
output.writeLong(fileSplitterFetch.nEndPos); p%_#"dkC7  
} s5>=!yX  
output.close(); -.:[a3c?  
} ;"=a-$vm  
catch(IOException e){e.printStackTrace ();} ,Y EB?HA  
catch(Exception e){e.printStackTrace ();} +2=N#LM  
} a!}.l< )  
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k/W$)b:Of`  
//读取保存的下载信息（文件指针位置） zFh JLH*C  
private void read_nPos() lL~T@+J~  
{ 0t<]Uf  
try{ +]/_gz  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5An|#^]  
int nCount = input.readInt(); MzRURH,  
nStartPos = new long[nCount]; @2-Eky  
nEndPos = new long[nCount]; PZ~uHX_d>  
for(int i=0;i<nStartPos.length;i++) *Z=K9y,IC  
{ 4flyV -  
nStartPos = input.readLong(); ]Kb  
nEndPos = input.readLong(); 3!^5a%u  
} x|G#oG)_  
input.close(); |l(rR06#.]  
} s8.OL_e  
catch(IOException e){e.printStackTrace ();} LbDhPG`u  
catch(Exception e){e.printStackTrace ();} @a) x^d  
} pPm[<^\#S  
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private void processErrorCode(int nErrorCode) L)JpMf0  
{ .w^M?}dx  
System.err.println("Error Code : " + nErrorCode); /u{ 9UR[g  
} L3P_  
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Me[T=Tt`@w  
//停止文件下载 .Ya]N+r*  
public void siteStop() P&C,EE$  
{ E^_P  
bStop = true; x]lv:m\)jT  
for(int i=0;i<nStartPos.length;i++) w1EYXe  
fileSplitterFetch.splitterStop(); =1f
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} ,/{mRw%  
} a?K=  
//负责部分文件的抓取 )s(J8J[b*L  
**FileSplitterFetch.java )Ac+5bs  
*/ vr2tIKvpn  
package NetFox; 6,)!\1k  
+Ck F#H ~  
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import java.io.*; rxjMCMF  
import java.net.*; Mh>H5l.1i  
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public class FileSplitterFetch extends Thread { _|rrl
 
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String sURL; //File URL \k_0wt2x1  
long nStartPos; //File Snippet Start Position *
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long nEndPos; //File Snippet End Position #\*ODMk$4|  
int nThreadID; //Thread's ID q
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boolean bDownOver = false; //Downing is over fQc2K|V  
boolean bStop = false; //Stop identical T;X8T  
FileAccessI fileAccessI = null; //File Access interface 48Y5ppcS  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \](IBI:  
{ ao>bnRXR  
this.sURL = sURL; B5pMcw  
this.nStartPos = nStart; F@4XORO;  
this.nEndPos = nEnd; ?#ue:O1  
nThreadID = id; {C Qo}@.7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 He="S3XON  
} '$*d:1  
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public void run() [4sI<aH  
{ J Sz'oA5
 
while(nStartPos < nEndPos && !bStop) ,A9pj k'  
{ 3Vjuk7  
8v"tOa4D7  

#=UEx  
try{ -~ytk=  
URL url = new URL(sURL); Y%:FawR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <T{2a\i 4f  
httpConnection.setRequestProperty("User-Agent","NetFox"); )nU%}Z  
String sProperty = "bytes="+nStartPos+"-"; Fv=7~6~  
httpConnection.setRequestProperty("RANGE",sProperty); bs$x%CR  
Utility.log(sProperty); jC>l<d_  
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InputStream input = httpConnection.getInputStream(); De,4r(5  
//logResponseHead(httpConnection); @=q,,t$r  
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b  
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byte[] b = new byte[1024];  Hi#'h  
int nRead; 2GQq(_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) VQF!|*#  
{ B4 5B`Ay  
nStartPos += fileAccessI.write(b,0,nRead); Y\luz`v  
//if(nThreadID == 1) &n+3^
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n-[J+DdB  
} uZ][#[u  
}yCJ#}  
vAiNOpz#  
Utility.log("Thread " + nThreadID + " is over!"); J&%vBg^  
bDownOver = true; E"!C3SC [  
//nPos = fileAccessI.write (b,0,nRead); dP[l$/  
} qG3 [5lti  
catch(Exception e){e.printStackTrace ();} jXq~ x"(  
} xevG)m  
} -]"=b\Q  
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//打印回应的头信息 Dv?'(.z  
public void logResponseHead(HttpURLConnection con)
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{ xxOo8+kA  
for(int i=1;;i++) `"QUA G  
{ g{wIdV  
String header=con.getHeaderFieldKey(i); (v(!l=3  
if(header!=null) .CH0P
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;m$F~!Y  
Utility.log(header+" : "+con.getHeaderField(header)); =t1.j=oC  
else d (]t}  
break; un0tzz  
} }Zu2GU$6  
} (yQ]n91Q,  
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public void splitterStop() 6#VG,'e3  
{ Okm&b g  
bStop = true; QA7SQcd,  
} eA9U|&o  
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} v<iMlOEt  
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/* +;SQ}[  
**FileAccess.java o<P@:}K  
*//文件访问(定位，写) :Z(?Ct&8  
package NetFox; |5)~WoV/G  
import java.io.*; Srj%6rgsB  
u%?u`n2'  
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public class FileAccessI implements Serializable{ CBdSgHA3>  
7 y}b (q=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 k+S+: 5  
RandomAccessFile oSavedFile; -a(f-  
long nPos; Jhu<^pjs  
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public FileAccessI() throws IOException F4X/ )$Dk  
{ 'TpW-r:  
this("",0); l!e8=QlJ  
} l=*^FK]L`  
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public FileAccessI(String sName,long nPos) throws IOException 'JY*K:-  
{ UI|L;5  
oSavedFile = new RandomAccessFile(sName,"rw"); D.xN_NK"  
this.nPos = nPos; _ b}\h,Ky  
oSavedFile.seek(nPos); hH:7
 
} @<Au|l`  
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public synchronized int write(byte[] b,int nStart,int nLen) ~LGkc t  
{ ElAJR4'{*i  
int n = -1; )%%RI_JT  
try{ cAC2Xq  
oSavedFile.write(b,nStart,nLen); eU_|.2  
n = nLen; R-]QU`c  
} _H@s^g  
catch(IOException e) dj4 g  
{
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e.printStackTrace (); Us.yKAHPV  
} `Yp\.K z  
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return n;
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} g(<02t!OT=  
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} Dr6"~5~9w  
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/* 1Lwi?~!LI  
**SiteInfoBean.java C3-l(N1O{  
*/ pVn6>\xa  
package NetFox; f]"][!e!,  
oQ~Q?o]Ri  
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public class SiteInfoBean { E>TD`  
m s\:^a  
6"WR}S0o  
private String sSiteURL; //Site's URL A=|LMJMWR  
private String sFilePath; //Saved File's Path q:#,b0|bv  
private String sFileName; //Saved File's Name -_'M *-  
private int nSplitter; //Count of Splited Downloading File pr>Qu:  
[,Ts;Hy6Q  
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public SiteInfoBean() ;&e5.K+.Z  
{//nSplitter的缺省值为5 E*IkI))X0  
//default value of nSplitter is 5 Vi`+2%4  
this("","","",5); gwQL9 UYx  
} 1YR;dn  
(xK=/()}q  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n|NI]Qi*  
{ wRf_IBhCd  
sSiteURL= sURL; 1JgnuBX"  
sFilePath = sPath; mB;W9[  
sFileName = sName; <oV _EZ  
this.nSplitter = nSpiltter; liFNJd`|o+  
: Ey  
Nt67Ye3;  
} e.G&hJr  
_Pa(5-S'KR  
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public String getSSiteURL() e%x$Cb:znn  
{ 0sVCTJ@  
return sSiteURL; zm2&\8J  
} #QZg{  
ih2H~c>O  
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public void setSSiteURL(String value) ~b5aT;ObR  
{ O<S*bN>BF  
sSiteURL = value; J5k\R+\H  
} >!E:$;i@  
/7|u2!#Ui  
KQ?E]}rZ  
public String getSFilePath() )=9\6zXS  
{ IkH
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return sFilePath; &GwBxJ  
} R`G%eG)+  
:<gmgI  
.Xo, BEjE/  
public void setSFilePath(String value) ywmx6q4MFL  
{ N4!YaQQ;}  
sFilePath = value; 7u,56V?X  
} 3nd02:GF  
{#uX   
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public String getSFileName() o; 6\  
{ sBS\S  
return sFileName; T_6,o[b8  
} &of%;>$>M  
M
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public void setSFileName(String value) t?28s/?  
{ 9/D+6hJ]:  
sFileName = value; go6Hb>  
} Gw!jYnU  
")ow,r^"  
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public int getNSplitter() J[L$8y:  
{ Mb3,!  
return nSplitter; E8jdQS|i
 
} &AGV0{NMh]  
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public void setNSplitter(int nCount) $k@reN9  
{ %,a.431gi  
nSplitter = nCount; :CSys62
 
} mn*.z!N=  
} q ]rsp0P2  
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E~2}rK+#)  
/* 3RscuD&  
**Utility.java q{@>2Al
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*/ o?$D09j;;  
package NetFox; p}R)qz-=5U  
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public class Utility { p4<&NMG  
)oG_x{  
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public Utility() :2 ?dl:l  
{ $Xk1'AzB8  
)eY3[>`  
cli
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} 3 _:yHwkD  
j?/T7a^  
//线程睡眠 W)<us?5Ec5  
public static void sleep(int nSecond) $4>K2  
{ p:k>!8.Qho  
try{ Wh(V?!^@5  
Thread.sleep(nSecond); 2<fG= I8  
} ?b2"~A  
catch(Exception e) -nN}8&l  
{  s4;
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e.printStackTrace (); q3T'rw%Eh  
} l *yml  
} 1`5d~>fV  
qW][Q%'lt  
//日志 /JtKn*?}:>  
public static void log(String sMsg) h?bm1e5kE  
{ e}(ws~.  
System.err.println(sMsg); "%<Oadz ap  
} 6~&4>2b0f  
`WC~cb\  
6jRF[N8  
public static void log(int sMsg) xO'1|b^&  
{ /=lrdp!a  
System.err.println(sMsg); e {N8|l  
} ,;O+2TX  
} 4punJg~1  
;wp)E nF  
>7@F4a  
/* ,X+mXtg.  
**TestMethod.java opjrU$<]N  
*/ NL0X =i  
package NetFox; "npj%O<bd  
HMS9_#[kE  
72&xEx  
public class TestMethod { PD:" SfV,G  
L 2Os\  
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public TestMethod() 5bH@R@3m  
{ ///xx/weblogic60b2_win.exe ?%iAkV  
try{ &( b\jyf  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); wP+wA}SN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (VWTYG7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); U:#9!J?41  
fileFetch.start(); mUm9[X~'  
} @;G}bYq^(I  
catch(Exception e){e.printStackTrace ();} (4>k+ H  
j Bl I^  
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} |B;:Ald  
<S6|$7{1  
(YGJw?]  
public static void main(String[] args) `V$i*{c:#  
{ FlrLXTx0  
new TestMethod(); X@\rg}kP  
} x!tCK47Yq  
} [wjA8d.  
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