http断点续传简单实现（java)

/* .')^4\  
**SiteFileFetch.java 6X$nZM|g,  
*/ 15%6;K?b  
package NetFox; n#B}p*G  
import java.io.*; wB+F/]]|N  
import java.net.*; ^==Tv+T9U  
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public class SiteFileFetch extends Thread { o@C|*TXN  
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SiteInfoBean siteInfoBean = null; //文件信息Bean }iLi5Qkx  
long[] nStartPos; //开始位置 fG{3S:TQq  
long[] nEndPos; //结束位置 =l6WO*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $>Ow<!c  
long nFileLength; //文件长度 x@:98P  
boolean bFirst = true; //是否第一次取文件 kV3LFPf>0  
boolean bStop = false; //停止标志 ;Rm';IW$  
File tmpFile; //文件下载的临时信息 n7zM;@{7  
DataOutputStream output; //输出到文件的输出流 7nM<P4\  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^;?
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public SiteFileFetch(SiteInfoBean bean) throws IOException $XKUw"%  
{ VW^q|B yB  
siteInfoBean = bean; T8x/&g''  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y5VohVa`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); y{XNB}E  
if(tmpFile.exists ()) %{me<\(  
{ zB\ 8<97C  
bFirst = false; gLx?0eBBA  
read_nPos(); -W:@3\{  
} dN){w _  
else [~;wCW,1  
{ (X (:h\^  
nStartPos = new long[bean.getNSplitter()]; L$jii  
nEndPos = new long[bean.getNSplitter()]; Upm#:i|"  
} HD,6  
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} !u`f?=s;  
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public void run() j}8^gz]  
{ 2"o<>d  
//获得文件长度 =sS=  
//分割文件 D^{jXNDNO  
//实例FileSplitterFetch Gr3 q  
//启动FileSplitterFetch线程 ]0{,P !  
//等待子线程返回 h^J :k  
try{ p%OVl[^jp  
if(bFirst) J.0&gP V  
{ &3*r-9BZ  
nFileLength = getFileSize(); -{yG+1  
if(nFileLength == -1) +ERuZc$3,  
{ LI"N^K'z  
System.err.println("File Length is not known!"); S:c lyx  
} ![Vrbe P  
else if(nFileLength == -2) ,yi@?lc  
{ $% W.=a'5  
System.err.println("File is not access!"); kioIyV\=  
} -1R7 8(1  
else m# ^).+  
{ ^brh\M,:@  
for(int i=0;i<nStartPos.length;i++) d~b@F&mf  
{ ?W&a
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); c>C!vAg  
} ==bT0-M.~  
for(int i=0;i<nEndPos.length-1;i++)
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{ G2J4N2hu  
nEndPos = nStartPos[i+1]; eBe5H =I@  
} vNU[K%U  
nEndPos[nEndPos.length-1] = nFileLength; #;'*W$Wk2  
} 0LP>3"Sm  
} g;y*F;0@  
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//启动子线程 oMN Qv%U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5)M#hx%]#  
for(int i=0;i<nStartPos.length;i++) "l6Ob
 
{ "04:1J`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1sfs!b&E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ude)$PAe%  
nStartPos,nEndPos,i); Uz7V2r%]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I4zm{ 1g  
fileSplitterFetch.start(); c5{3  
} +#g4Crb  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g^:7mG6C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q!W+vh  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &F +hh{  
nEndPos = " + nFileLength); SwhArvS  
// fileSplitterFetch[nPos.length-1].start(); f<@`{oP@  
0U:9&jP,  
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//等待子线程结束 `I5So-^&z  
//int count = 0; $60]R
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//是否结束while循环 B{Lcx~  
boolean breakWhile = false; qTnk>g_oS&  
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while(!bStop) IN!IjInaT@  
{ ~ponYc.Y  
write_nPos(); 0S>U_#-  
Utility.sleep(500); `~ R%}ID  
breakWhile = true; :FI4GR*?  
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for(int i=0;i<nStartPos.length;i++) 8_@#5  
{ _PeB
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if(!fileSplitterFetch.bDownOver) e$+?l~  
{ F7zBm53  
breakWhile = false; A!Ls<D
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break; H%:~&_D  
} 8}kY^"*&X  
} T};fy+iq  
if(breakWhile) OK}+:Y  
break; kK[m=rTx1$  
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//count++; .?YLD+\A  
//if(count>4) 45;{tS.z,B  
// siteStop(); :3# t;  
} Qr4c':
8  
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System.err.println("文件下载结束！"); g6kVHxh-  
} <-:gaA`KM  
catch(Exception e){e.printStackTrace ();} HV^*_  
} eVZ/3o  
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//获得文件长度 :b&O{>M]Y  
public long getFileSize() ~97T0{E3  
{ Ub8|x]ix  
int nFileLength = -1; j`Xe0U<  
try{ n 4:Yc@,  
URL url = new URL(siteInfoBean.getSSiteURL()); (0Xgv3wd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (q!tI*}  
httpConnection.setRequestProperty("User-Agent","NetFox"); c:
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int responseCode=httpConnection.getResponseCode(); UGNFWZ c  
if(responseCode>=400) |5 sI=?p&t  
{ _ FcfNF  
processErrorCode(responseCode); gu[3L  
return -2; //-2 represent access is error M4rOnIJ  
} :_%  
ON{
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String sHeader; jOppru5U  
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for(int i=1;;i++) `k}  
{ _ 13M
 
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); t0*JinKI  
//Utility.log(in.readLine()); g|r:+%,M  
sHeader=httpConnection.getHeaderFieldKey(i); )E<<
  
if(sHeader!=null) Tz H*?bpP  
{ m"P"iK/Av(  
if(sHeader.equals("Content-Length")) ^1rw\Zp  
{ [:geDk9O#'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d>z?JDt  
break; V#:`:-$$+  
} t =ErJ  
} &[*F!=%8  
else >E&mNp  
break; 9S ~!!7oj  
} H@$\SUc{  
} >1[Hk0 <x  
catch(IOException e){e.printStackTrace ();} eJ+V!K'H2  
catch(Exception e){e.printStackTrace ();} ^lCys  
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Utility.log(nFileLength); @GzEhv  
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return nFileLength; >'4Bq*5>  
} l$$N~FN  
ob=GB71j55  
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//保存下载信息（文件指针位置） ", b}-B  
private void write_nPos() ZOGH.`  
{ N>?R,XM V  
try{ ;h>s=D,r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'ojI_%9<  
output.writeInt(nStartPos.length); >'3J. FY  
for(int i=0;i<nStartPos.length;i++) J,ZvaF  
{ ~GJJ{Bm_  
// output.writeLong(nPos); SsiKuoxk  
output.writeLong(fileSplitterFetch.nStartPos); Mq!03q6  
output.writeLong(fileSplitterFetch.nEndPos); 2x-67_BHY=  
} G"3)\FEM  
output.close(); {7!WtH;-  
} "' g*_  
catch(IOException e){e.printStackTrace ();} fMaUIJ:Q9  
catch(Exception e){e.printStackTrace ();} #Aox$[|@  
} FVOR~z  
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//读取保存的下载信息（文件指针位置） mF\r]ovVm  
private void read_nPos() MY11 5%  
{ (rV#EA+6[`  
try{ e1ru#'z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); /7Z;/|oU  
int nCount = input.readInt(); AW;"` ].  
nStartPos = new long[nCount]; ,B]kX/W  
nEndPos = new long[nCount]; B.nq3;Y  
for(int i=0;i<nStartPos.length;i++) x}I'
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{ {Muw4DV  
nStartPos = input.readLong(); {Rb|";  
nEndPos = input.readLong(); \Ub=Wm\
 
} c}K>#{YeB  
input.close(); 6j9P`#Lt  
} 71i".1l{K  
catch(IOException e){e.printStackTrace ();} Ym~*5|  
catch(Exception e){e.printStackTrace ();} h^#K4/  
} yM(zc/?  
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private void processErrorCode(int nErrorCode) L
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{ u`Kjs}F'  
System.err.println("Error Code : " + nErrorCode); W#1t%hT$  
} #?h#R5:0  
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//停止文件下载 $agd9z,&m  
public void siteStop() 0mj^Tms  
{ V4Yw"J  
bStop = true; F6 ?4E"d  
for(int i=0;i<nStartPos.length;i++) ?ysC7((  
fileSplitterFetch.splitterStop(); PfKIaW<  
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}  p]z *  
} r@;n \  
//负责部分文件的抓取 9L+dN%C  
**FileSplitterFetch.java 6BT o%  
*/ 5[\m
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package NetFox; D,Ft*(|T  
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import java.io.*; +[$d9  
import java.net.*; I8=p_Ie
 
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public class FileSplitterFetch extends Thread { Ra%" +=  
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String sURL; //File URL BfmSM9  
long nStartPos; //File Snippet Start Position no_(J>p^&  
long nEndPos; //File Snippet End Position *z-Mr~V  
int nThreadID; //Thread's ID WVPnyVDc  
boolean bDownOver = false; //Downing is over Kfho:e,  
boolean bStop = false; //Stop identical Ys8p,.OMs  
FileAccessI fileAccessI = null; //File Access interface 34lt?6%j  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException saMv.;s 1^  
{ 7}+U;0,)  
this.sURL = sURL; o/uA_19  
this.nStartPos = nStart; |L XYF$  
this.nEndPos = nEnd; JWHKa=-H  
nThreadID = id; q$>/~aVM  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 yHS=8!
  
} hrsMAh!  
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public void run() 3K Y-+ k  
{ Q2wEt >0a  
while(nStartPos < nEndPos && !bStop) }:NE  
{ ~y@,d  
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try{ 2%0J/]n\A"  
URL url = new URL(sURL); FbxrBM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7GN>o@t  
httpConnection.setRequestProperty("User-Agent","NetFox"); O5^!\j.WR  
String sProperty = "bytes="+nStartPos+"-"; $]eU'!
2)  
httpConnection.setRequestProperty("RANGE",sProperty); KW^#DI6tr  
Utility.log(sProperty); F'eV%g  
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InputStream input = httpConnection.getInputStream(); *;(wtMg  
//logResponseHead(httpConnection); }u"iA^'Ot  
\*5`@>_  
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byte[] b = new byte[1024]; t[L0kF9en  
int nRead; qo2/?
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *AEN  
{ @9yY`\"ed  
nStartPos += fileAccessI.write(b,0,nRead); }bwH(OOS  
//if(nThreadID == 1) }=)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +k@$C,A  
} lPA:aHcj  
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Utility.log("Thread " + nThreadID + " is over!"); %!_okf  
bDownOver = true; sj@B0R=Qo  
//nPos = fileAccessI.write (b,0,nRead); fU@{!;|Pz  
} 'q+CL&D  
catch(Exception e){e.printStackTrace ();} 0taopDi;d  
} 2(5HPRQ  
} }E?{M~"<  
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//打印回应的头信息 ^cQTRO|  
public void logResponseHead(HttpURLConnection con) "qb1jv#to  
{ z: x|;Ps!  
for(int i=1;;i++) N~<H`  
{ ;QVX'?  
String header=con.getHeaderFieldKey(i); &y164xn'h  
if(header!=null) zkFx2(Hq-f  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  3+[R
!  
Utility.log(header+" : "+con.getHeaderField(header)); IaDN[:SX  
else =D1%-ym  
break;
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} *b< a@  
} S"*M9*8  
/hx|KC&:e  
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public void splitterStop() 3_AVJv ;N  
{ p3sR>ToJ  
bStop = true; wOhiC$E46  
} Tc{n]TV  
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} =wd=TX/  
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/* Q db~I#}m'  
**FileAccess.java 1Wz -Z  
*//文件访问(定位，写) o.)8A8  
package NetFox; ncF|wz  
import java.io.*; QX1rnVzg0  
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public class FileAccessI implements Serializable{ ~M>EB6  
@raw8w\Zj+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 zvzS$Gpe  
RandomAccessFile oSavedFile; ZmJ!ZKKch  
long nPos; Jp'XZ]o\  
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public FileAccessI() throws IOException X {["4  
{ ,3m]jp'  
this("",0); , Ww\C  
}
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public FileAccessI(String sName,long nPos) throws IOException [<2#C#P:6  
{ #_A <C+[  
oSavedFile = new RandomAccessFile(sName,"rw"); PYOU=R%o`8  
this.nPos = nPos; 5BztOYn,  
oSavedFile.seek(nPos); 72YL   
} <c,/+ lQ^  
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public synchronized int write(byte[] b,int nStart,int nLen) cz2guUu  
{ ,wI$O8"!j  
int n = -1; NI@$"  
try{ X2Z E9b  
oSavedFile.write(b,nStart,nLen); [f_4%Now  
n = nLen; h1y6`m9  
} c
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catch(IOException e) ?8j#gYx2  
{ ?gq',FFDq  
e.printStackTrace (); r_5k$u(  
} v(ATbY75  
+[=yLE#P%  
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return n; \Y EV 5  
} isdEs k#A.  
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} qtx5N)J6  
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/* v,\2$q/  
**SiteInfoBean.java *jB
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*/ f/FK>oUh  
package NetFox; dHcGe{T^(  
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public class SiteInfoBean { # j
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private String sSiteURL; //Site's URL 5
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private String sFilePath; //Saved File's Path 80/6-_g(  
private String sFileName; //Saved File's Name 5y}kI  
private int nSplitter; //Count of Splited Downloading File d/Sx+1 "{T  
if S) < t  
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public SiteInfoBean() w Wx,}=  
{//nSplitter的缺省值为5 W6Os|z9&|  
//default value of nSplitter is 5 {kLL&`ii  
this("","","",5); F-=W7 D:[c  
} VTD
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %-Z0OzWe  
{ y=L9E?  
sSiteURL= sURL; Lv;R8^n  
sFilePath = sPath;
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sFileName = sName; Q( WE.ux)<  
this.nSplitter = nSpiltter; lgxG:zAC  
. Q#X'j  
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} zU+` o?al  
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public String getSSiteURL() Min^EAG@  
{ kEM5eY  
return sSiteURL; htn"rY(  
} {9 >jWNx  
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public void setSSiteURL(String value) =6mnXpM.  
{ `-l,`7e'  
sSiteURL = value; e ;4y5i  
} y;N[#hY#CD  
]jUxL=]r  
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public String getSFilePath() #+2|ZfCn%  
{ ,0^:q)_  
return sFilePath; x(e=@/qp  
} Z4\$h1tl  
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public void setSFilePath(String value) <y+8\m  
{ 6Xjr0C+  
sFilePath = value; 5feCA ,v7  
} ^Zh YW  
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public String getSFileName() tUXq!r<'dT  
{ 'F'v/G~
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return sFileName; < PoRnx  
} ^(p}hSLAfQ  
:tu_@3bg-  
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public void setSFileName(String value) /J8'mCuC.  
{ ~F`t[p  
sFileName = value; I!y[7^R  
} IrU}%ZVV  
;;E "+.  
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public int getNSplitter() ;C8'7  
{ Z:|2PQ4  
return nSplitter; sF?N vp  
} SSANt?\Z<  
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public void setNSplitter(int nCount) ]XEkQ  
{ 6aG/=fq  
nSplitter = nCount; :%Dw3IrOM  
} XDvT#(Pu  
} <tZPS`c'_  
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`F:PWG`  
/* .^^YS$%%7  
**Utility.java hS4Ljyeg  
*/ 9k_3=KS3N  
package NetFox; ?^9TtxM  
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public class Utility { M>df7.N7%P  
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public Utility() \[&~.B  
{ .IYE+XzV  
2 @g'3M  
{\G4YQ  
} v7VJVLH,I7  
S86%o,Saq\  
//线程睡眠 ='=\!md  
public static void sleep(int nSecond) kWL\JDZ`.  
{ =)C}u6  
try{ F|X-|Co  
Thread.sleep(nSecond); %k#Q)zWJ  
} xz YvD{>  
catch(Exception e) &#Sg1$/+  
{ M?5[#0"&V  
e.printStackTrace (); `zAo IQ  
} CqDMq!  
} KLlo^1.<  

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//日志 @AL,@P/9=  
public static void log(String sMsg) }9e4?7  
{ 0q"&AxNsP  
System.err.println(sMsg); ?lCKZm.,(-  
} !8ub3oj)  
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public static void log(int sMsg) Mq]~Ka3q7  
{ JI5?, )-St  
System.err.println(sMsg); *iS<]y  
} ;5-Sn(G  
} rixNz@p'%  
xtN%v0ZZ  
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/* 3.B|uN  
**TestMethod.java HKx2QFB  
*/ ro7\}O:I  
package NetFox; ?G+v#?A  
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public class TestMethod { #)_4$<P*'  
$+zev$f  
;i
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public TestMethod() <oTIzj7f  
{ ///xx/weblogic60b2_win.exe k61Ot3  
try{ 2@Jw?+}vr  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L~SM#?z:ue  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); z+&mMP`-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >f4H<V-  
fileFetch.start(); \MQ|(  
} ;OTD
1=  
catch(Exception e){e.printStackTrace ();} }
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} [F%INl-sy  
" GkBX  
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public static void main(String[] args) l~Hs]*jm  
{ B.6gJ2c  
new TestMethod(); 6<.Ma7)lA  
} Hq"i0Xm  
} DY'D]*'7$  
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