http断点续传简单实现（java)

/* F\bI6gj  
**SiteFileFetch.java A!yLwkc:5  
*/ ze)K-6SKH  
package NetFox; {fD#=  
import java.io.*; Al}PJz\  
import java.net.*; ,O$C9pH9  
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public class SiteFileFetch extends Thread { Lm#d.AD)  
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SiteInfoBean siteInfoBean = null; //文件信息Bean |'
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long[] nStartPos; //开始位置 [rU8 #4.  
long[] nEndPos; //结束位置 89mre;v`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "~ stZ.  
long nFileLength; //文件长度 @un }&URp  
boolean bFirst = true; //是否第一次取文件 2"mj=}y6  
boolean bStop = false; //停止标志 8 GN{*Hg  
File tmpFile; //文件下载的临时信息 F9r*ZyNlx  
DataOutputStream output; //输出到文件的输出流 vy2aNUmt  
ZQA C&:  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5&=n  
public SiteFileFetch(SiteInfoBean bean) throws IOException )W|jt
/  
{ p>3'77 V  
siteInfoBean = bean; n4y6Ua9m{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %;$Y|RbmqE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _B FX5ifK  
if(tmpFile.exists ()) 38i,\@p`9$  
{ K9'*q3z  
bFirst = false; 8-YrmP2k  
read_nPos(); WEAXqDjM  
} +Ob#3PRy  
else *wcoDQ b;  
{ 4+,Z'J%\[7  
nStartPos = new long[bean.getNSplitter()]; #SNI dc>9\  
nEndPos = new long[bean.getNSplitter()]; Fg_s'G,`  
} *PU,Rc()6  
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} %=y3  
Q}]
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public void run() tta0sJ8i  
{ ] Nipo'N;  
//获得文件长度 aZ`agsofk  
//分割文件 ;@~*z4U  
//实例FileSplitterFetch I]1Hi?A2  
//启动FileSplitterFetch线程 |9$'?4F  
//等待子线程返回 5V8C+k)  
try{ j88sE MZ  
if(bFirst) Fxx2vTV4ag  
{ w{EU9C
 
nFileLength = getFileSize(); 6FMW g:{  
if(nFileLength == -1) X.9MOdG70  
{ uA`PZ|  
System.err.println("File Length is not known!"); ER1mA:8>E  
} 6'!{0 5=m  
else if(nFileLength == -2) =2)t1 H  
{ s/H"Ab  
System.err.println("File is not access!"); 3eP0v  
} 8w?\_P7QA  
else ;I71_>m  
{ g@VndAp  
for(int i=0;i<nStartPos.length;i++) _rdj,F8  
{ D#}Yx]Q1  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Am0C|(#Xm  
} q*TKs#3  
for(int i=0;i<nEndPos.length-1;i++) Ab<Ok\e5  
{ b
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nEndPos = nStartPos[i+1]; jZ,[{Z(N   
} h!
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nEndPos[nEndPos.length-1] = nFileLength; JMlhBh  
} \[I .  
} $=xQX  

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i/~QJ1C  
//启动子线程 h^$
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \OT)KVwO  
for(int i=0;i<nStartPos.length;i++) ^6y4!='ci  
{ k|Yv8+XT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f.)F8!!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), v|2q2bz  
nStartPos,nEndPos,i); m{dyVE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (jMAa%
  
fileSplitterFetch.start(); Cf=q_\0|W  
} P`IG9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (,c?}TP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A-C)w/7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]O=S2Q  
nEndPos = " + nFileLength); -<JBKPtA  
// fileSplitterFetch[nPos.length-1].start(); [*{\R`M  
+xBK^5/x  
#Y>%Dr&  
//等待子线程结束 VSpt&19  
//int count = 0; wW! r}I#  
//是否结束while循环 X+E\]X2  
boolean breakWhile = false; KSB_%OI1  
Yj7= T%5  
Q>a7Ps@~  
while(!bStop) /,N!g_"Z  
{ >dvWa-rNUT  
write_nPos(); s?x>Yl %  
Utility.sleep(500); 'BdmFKy1  
breakWhile = true; ^!p<zZ  
+[8Kl
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for(int i=0;i<nStartPos.length;i++) Q] yT  
{ C6V&R1"s  
if(!fileSplitterFetch.bDownOver) 0"qim0%|DF  
{ /\a]S:V-j  
breakWhile = false; !:O/|.+Vmf  
break; OV("mNh  
} LLn{2,jfQ  
} p@7i=hyt`p  
if(breakWhile) *(&ClUQQ  
break; .4C[D{4  
>yA,@%X  
^A"lkV7  
//count++; K l0tyeT  
//if(count>4) J6( RlHS;  
// siteStop(); +>WC^s  
} qz=#;&ZU  
1'v!9  
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System.err.println("文件下载结束！"); m$E^u[  
} U|Z>SE<k  
catch(Exception e){e.printStackTrace ();} '
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} P 5qa:<  
9oz(=R  
,D@;i  
//获得文件长度 (4/]dTb  
public long getFileSize() W93JY0Ls9|  
{ &I}T<v{f  
int nFileLength = -1; 3q|cZQK!1  
try{ >4|c7z4  
URL url = new URL(siteInfoBean.getSSiteURL()); lKV\1(`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kBiBXRt  
httpConnection.setRequestProperty("User-Agent","NetFox"); l'7Mw%6{  
*L;pcg8{  
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int responseCode=httpConnection.getResponseCode(); P7wqZ?  
if(responseCode>=400) >)n4sMq  
{ ,bVS.A'o  
processErrorCode(responseCode); WE.$at{*h  
return -2; //-2 represent access is error y  KYP  
} iIGI=EwZ  
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String sHeader; b$goF }b'g  
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for(int i=1;;i++) NlF0\+h  
{ rWFcIh5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {7=WU4$  
//Utility.log(in.readLine()); ]~prR?  
sHeader=httpConnection.getHeaderFieldKey(i); Y%fVt|  
if(sHeader!=null) {C/L5cZ]J  
{ wTlK4R#  
if(sHeader.equals("Content-Length")) ;J(rw  
{ &}nBenYp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !]rE
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break; pFsCd"zv  
} &SjHrOG?  
} .|-l+  
else S$jV|xKB  
break; <}EV*`w4  
} B?;' lDz*  
} -Wlp=#9  
catch(IOException e){e.printStackTrace ();} <Qcex3  
catch(Exception e){e.printStackTrace ();} )+n,5W  
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Utility.log(nFileLength); ePq13!FC/  
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return nFileLength; =f4[=C$&`  
} \LdmGv@&  
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//保存下载信息（文件指针位置） la\zaKC;>  
private void write_nPos() xS;|jj9  
{ OU,PO2xX9  
try{ =My}{n[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &Y54QE".  
output.writeInt(nStartPos.length); Fl_dzh,E  
for(int i=0;i<nStartPos.length;i++) sK`~Csb iB  
{ *L%6qxl`V  
// output.writeLong(nPos); %RQC9!  
output.writeLong(fileSplitterFetch.nStartPos); x">W u2  
output.writeLong(fileSplitterFetch.nEndPos); eVw\v#gd  
} [j)\v^m  
output.close(); ]#Vo}CVP  
} +Lm3vj_N  
catch(IOException e){e.printStackTrace ();} j+DE|Q&]I  
catch(Exception e){e.printStackTrace ();} 1B)Y;hg6&  
} 7P<r`,~k-  
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&1
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//读取保存的下载信息（文件指针位置） oA4D\rn8"  
private void read_nPos() `Yx-~y5X  
{ 0'?V|V=v  
try{ vKNt$]p
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); q2x|%HRF  
int nCount = input.readInt(); .i{>Z  
nStartPos = new long[nCount]; AbUDn\0$  
nEndPos = new long[nCount]; omM&{ }8g  
for(int i=0;i<nStartPos.length;i++) ~ X-)_zH  
{ p?+lAbe6H  
nStartPos = input.readLong(); uiktdZ/f  
nEndPos = input.readLong(); vk @%R  
} 1)TK01R8  
input.close(); $%7I:  
} 8tb6 gZz  
catch(IOException e){e.printStackTrace ();} yicO!:bM  
catch(Exception e){e.printStackTrace ();} :s'o~  
} -O|&c9W.O  
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private void processErrorCode(int nErrorCode) k?3S  
{ ;i<$7MR.e  
System.err.println("Error Code : " + nErrorCode); 51I|0ly  
} ;mDM5.iF  
9
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h ?uqLsRl  
//停止文件下载 L
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public void siteStop() U'tE^W  
{ FH)t:!#  
bStop = true; F-_%>KJS  
for(int i=0;i<nStartPos.length;i++) ;wJ~haC  
fileSplitterFetch.splitterStop(); $o]r]#B+  
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} 6}ce1|mkg/  
} 41u*w2j  
//负责部分文件的抓取 1hl
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**FileSplitterFetch.java >A-<ZS*N  
*/ 6gXIt9B.h$  
package NetFox; l0I}&,+  
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_`H.h6h  
import java.io.*; K
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import java.net.*; <"W?<VjO  
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public class FileSplitterFetch extends Thread { #Mh{<gk%ax  
X*i/A<Y`=  
/ /'Tck  
String sURL; //File URL :z]}ZZ  
long nStartPos; //File Snippet Start Position {jjSJIV1  
long nEndPos; //File Snippet End Position MhNFW'_  
int nThreadID; //Thread's ID j`O7=-  
boolean bDownOver = false; //Downing is over }.p<wCPy6  
boolean bStop = false; //Stop identical + :Vrip  
FileAccessI fileAccessI = null; //File Access interface /D<"wF }@J  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException F*M|<E=  
{ [QT1Ju64  
this.sURL = sURL; f|U0s  
this.nStartPos = nStart; baee?6  
this.nEndPos = nEnd; +iy7e6P  
nThreadID = id; ` @8`qXg  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 XAPYpBgm  
} ~4\,&HH  
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public void run() qos`!=g?  
{ 1~J5uB
4  
while(nStartPos < nEndPos && !bStop) K%MW6y  
{ cq*=|m0}Z  
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try{ h>alGLN>  
URL url = new URL(sURL); 'CXRG$
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %K(0W8&  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1j0-9Kg'  
String sProperty = "bytes="+nStartPos+"-"; z>;$im  
httpConnection.setRequestProperty("RANGE",sProperty);
[$\z'}  
Utility.log(sProperty); \?DR s  
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InputStream input = httpConnection.getInputStream(); C)Jn[/BD  
//logResponseHead(httpConnection); ME^,'&  
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byte[] b = new byte[1024]; N L'R\R  
int nRead; HRB[GP+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) fTqC:r|st  
{ o%[U
 
nStartPos += fileAccessI.write(b,0,nRead); Z)pz,  
//if(nThreadID == 1) #D*r]M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jTb-;4N'  
} w\w(U  
aE|OTm+@9;  
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Utility.log("Thread " + nThreadID + " is over!"); -kpswP  
bDownOver = true; ""{|3XJe  
//nPos = fileAccessI.write (b,0,nRead); Wkzs<y"  
} BI2; ex  
catch(Exception e){e.printStackTrace ();} +Llo81j&  
} 0:&ZnE}##  
} ~GJN@ka4%  
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//打印回应的头信息 WKmbNvN^  
public void logResponseHead(HttpURLConnection con) K>2#UzW  
{ AW,OHSXh6  
for(int i=1;;i++) K-eY|n  
{ "&~ 0T#  
String header=con.getHeaderFieldKey(i); >u0w.3r#  
if(header!=null) 4v'A\~ZU  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %UZVb V  
Utility.log(header+" : "+con.getHeaderField(header)); ^j)BKD-  
else K93p"nHN  
break; ]"~51HQZ  
} X"q!Y#)  
} w$|l{VI  
bU54-3Ox*  
hWo=;#B*  
public void splitterStop() ]3Dl)[R   
{ ,xI%A, (,;  
bStop = true; ;heHefbvvd  
} x;\wY'  
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} ;WU<CKYG*  
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/* (08I  
**FileAccess.java ,#]t$mzbQ(  
*//文件访问(定位，写) x3pND  
package NetFox; aqU' T  
import java.io.*; =Gk/k}1  
&~e$:8+  
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public class FileAccessI implements Serializable{ N#C1-*[C  
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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 _7T@5\b:;  
RandomAccessFile oSavedFile; up'  
long nPos; $ (=~r`O+1  
}!>=|1fY  
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public FileAccessI() throws IOException <plC_{Y:wu  
{
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this("",0); M$Zo.Bl$(  
} U`|0 jJ  
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public FileAccessI(String sName,long nPos) throws IOException \C^;k%{LV  
{ ra N)8w}-  
oSavedFile = new RandomAccessFile(sName,"rw"); qmy%J  
this.nPos = nPos; 1xE]6he4{T  
oSavedFile.seek(nPos); Mg,:UC:  
} +;}#B~:  
#-% A[7Cdp  
JPn$FQD  
public synchronized int write(byte[] b,int nStart,int nLen) k>jbcSY(z<  
{ $_H`   
int n = -1; 41a.#o  
try{ BvrB:%_:  
oSavedFile.write(b,nStart,nLen); fFvF\  
n = nLen; CzCQFqXI  
} xVL5'y1g B  
catch(IOException e) =qy=-j]  
{ 4_v]O  
e.printStackTrace (); Y
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} [+m?G4[  
l
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return n; >gwz,{  
} 5}$b0<em~  
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*=V7@o  
} *'Y@3vKE  
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&N~ZI*^  
/* UO*Ymj 1  
**SiteInfoBean.java [%Bf< J<  
*/ bwM@/g%DL  
package NetFox; !o=U19)  
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@yXfBML?]  
public class SiteInfoBean { ofYlR
|  
p Dx-2:}  
e!Y0-=?nf#  
private String sSiteURL; //Site's URL B+C);WQ,  
private String sFilePath; //Saved File's Path (/-hu[:  
private String sFileName; //Saved File's Name ae"]\a\&1o  
private int nSplitter; //Count of Splited Downloading File Ghl'nqPlm  
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public SiteInfoBean() \)K^=jM  
{//nSplitter的缺省值为5 I):!`R.,  
//default value of nSplitter is 5 #_Z$2L"U  
this("","","",5); ?m$a6'2-,J  
} Uj+j}C  
8t@p@Td|  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ev7J+TmXM  
{ mWR4|1(  
sSiteURL= sURL; oI)GKA_Ng7  
sFilePath = sPath; ?Kvl!F!`
 
sFileName = sName; ae:zWk'!  
this.nSplitter = nSpiltter; }ENR{vz$A  
+dA,P\  
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} W^3uEm&l!)  
322jR4QGr  
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public String getSSiteURL() r]
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{ JpsPNa  
return sSiteURL; O+}qQNe<  
} `wF8k{Pb  
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public void setSSiteURL(String value) dq[Mj5eC  
{ V=fEPM  
sSiteURL = value; <mi-}s  
} S=_vv)6+4  
2z\zh[(w  
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public String getSFilePath() 3}|'0(hYL  
{ Og=*R6i  
return sFilePath; z1^gDjkZ  
} CPg+f1K  
btdb%Q*  
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public void setSFilePath(String value) s w39\urf  
{ >``MR%E:<  
sFilePath = value; ~QvqG{bFB  
} "\0v,!@  
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/mp*>sNr6  
public String getSFileName() 8,0YD#x  
{ Y&/]O$<  
return sFileName; }%Bl>M
  
}
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lA>DS#_  
f!
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public void setSFileName(String value) )(y)A[  
{ pb#?l6x$+  
sFileName = value; r5!/[_l  
} CHV*vU<N  
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public int getNSplitter() }Tf9S<xpq3  
{ p~*UpU8u  
return nSplitter; 71vkyn@"  
} JH:0 L  
!S&L*OH,  
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public void setNSplitter(int nCount) $Y5)(  
{ o.q/O)'V u  
nSplitter = nCount; :n /@z4#  
} |&Ym@Jyj  
} 6252N]*  
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/* rj6#
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**Utility.java $H+VA@_  
*/ e["2QIOe  
package NetFox; LBF 1;zjK  
=m5SK5vLKT  
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public class Utility { Nbp!teH6
  
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public Utility() sg+uBCGB  
{ }1>[  
u%.$BD Hg  
0{#8',*}m?  
} ezPz<iZ\N  
v%f
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//线程睡眠 $V1;la!  
public static void sleep(int nSecond) K~22\G`  
{ 6ND`l5  
try{ ei rzYt  
Thread.sleep(nSecond); 4C FB"?n0  
} 
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catch(Exception e) W3iZ|[E;  
{ _6wFba@>/n  
e.printStackTrace (); }N*_KzPIa  
} G#MdfKH  
} gdkwWoN.  
Unsogd  
//日志 |Pg@M  
public static void log(String sMsg) B, 9w0  
{ NMA}Q$o s  
System.err.println(sMsg); jAud {m*T  
} /PLn+-  
#lkM=lY'  
(&!NC[n,  
public static void log(int sMsg) QcgfBsv96  
{ |jM4E$  
System.err.println(sMsg); Dgy]ae(Hb3  
} x:nKfY5  
} )KP5WudX  
@r?
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[o?*"c  
/* d9q(xZ5  
**TestMethod.java :H c0b=  
*/ 5|1T}Z#;  
package NetFox; zToq^T  
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3\X
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public class TestMethod { 0Q^Ikiv  
CxfRVL`7  
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public TestMethod() Aj0Tfdxy  
{ ///xx/weblogic60b2_win.exe 2 aL)  
try{ mQY_`&Jq  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); e#E2>Bj;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); lEV]4 t_H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9-rNw?7  
fileFetch.start(); 0=K9`=5d0  
} rta:f800z  
catch(Exception e){e.printStackTrace ();} -N"&/)  
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/RMPS. d {  
} `(3/$%  
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public static void main(String[] args) +-G<c6 |  
{ wR^RM(1  
new TestMethod(); -e8}Pm "  
} C?2'+K  
} $_
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