http断点续传简单实现（java)

/* u=9)A9  
**SiteFileFetch.java %9P)Okq  
*/ ( R0>0f@  
package NetFox; O]N 8QH  
import java.io.*; ~Y /55uC  
import java.net.*; Vs~!\<?
 
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public class SiteFileFetch extends Thread { Bq)aA)gF  
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SiteInfoBean siteInfoBean = null; //文件信息Bean s0bWg$  
long[] nStartPos; //开始位置 yqKERdm  
long[] nEndPos; //结束位置 +ZxG<1&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 AB1,G|L  
long nFileLength; //文件长度 1} h''p  
boolean bFirst = true; //是否第一次取文件 XI*cu\7sy  
boolean bStop = false; //停止标志 1L:sck5k  
File tmpFile; //文件下载的临时信息 +Xjevg6DU  
DataOutputStream output; //输出到文件的输出流 gjnTG:}}}+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） T($6L7 j9  
public SiteFileFetch(SiteInfoBean bean) throws IOException N&'05uWY}  
{ M,j3z#  
siteInfoBean = bean; U*7Yi-"/*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); K oF4e:2>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z UCz-53  
if(tmpFile.exists ()) +~L26T\8  
{ 69>N xr~k  
bFirst = false;  }FoO  
read_nPos(); 84uHK)h<%  
} 7TW</g(  
else 3(/J(8  
{ gkN )`/`*  
nStartPos = new long[bean.getNSplitter()]; 5$C]$o}  
nEndPos = new long[bean.getNSplitter()]; M7 Z9(3Va  
} 07:N)y,  
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} 1__Mf.A  
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public void run() GDUOUl&  
{ Kq
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//获得文件长度 t@1bu$y  
//分割文件 !04zWYHo  
//实例FileSplitterFetch !<P|:Oo*Dl  
//启动FileSplitterFetch线程 E6FT*}Q  
//等待子线程返回 mtQ
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try{ ejuw+@ _  
if(bFirst) = g[Cs*  
{ bEz1@"~ p  
nFileLength = getFileSize(); c7fQ{"f 3B  
if(nFileLength == -1) <.lT.>'?  
{ <#r/4a"V  
System.err.println("File Length is not known!"); [V-OYjPAx  
} {zf)im[.  
else if(nFileLength == -2) |{G GATni  
{ YrWC\HR_  
System.err.println("File is not access!"); mm,be.  
} It .`  
else `
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{ YLEa;MR  
for(int i=0;i<nStartPos.length;i++) HI}9"(t}  
{ |
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); vS$_H<;P  
} Mx<?c  
for(int i=0;i<nEndPos.length-1;i++) KS6H`Mm}/  
{ UD@u hL  
nEndPos = nStartPos[i+1]; c+^#(OB  
} _CDl9pP36#  
nEndPos[nEndPos.length-1] = nFileLength; @Pt,N qj
:  
} =oPc\VYW  
} IV5B5Q'D  
jbU=D:|  
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//启动子线程 1 ynjDin<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; T1&^IO-F7$  
for(int i=0;i<nStartPos.length;i++) 3Wl,T5}{  
{ ]$VYzE2e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uuA q\YZy/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :172I1|7  
nStartPos,nEndPos,i); UJWkG^?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8
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fileSplitterFetch.start(); q|23l1PI  
} 1JIo,7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z.]=u(=a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); EGKj1_ml  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", aj71oki)  
nEndPos = " + nFileLength); GWU"zWli]z  
// fileSplitterFetch[nPos.length-1].start(); ^^-uq)A  
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//等待子线程结束 CfWtCA  
//int count = 0; ~baVS-v  
//是否结束while循环 mimJ_=]DC  
boolean breakWhile = false; BV8-\R@  
?1G7=R  
79?%g=#=  
while(!bStop) lhk[U!>#  
{ 4%3R}-'mh  
write_nPos(); S-8wL%r  
Utility.sleep(500); 2KUm(B.I  
breakWhile = true; RK
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9EE},D  
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for(int i=0;i<nStartPos.length;i++) Y}/e"mp  
{ mF?GQls`  
if(!fileSplitterFetch.bDownOver) Y)-)owx7  
{ ?)ROQ1-#@  
breakWhile = false; g@<E0 q&`$  
break; bHi0N@W!vG  
} 9<9 c^2  
} i"h '^6M1  
if(breakWhile) y$]gmg  
break; I4%p?'i,C  
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//count++; |9;6Cp  
//if(count>4) G9/5KW}-  
// siteStop(); /-.i=o]b  
} PyS~2)=B  
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System.err.println("文件下载结束！"); cNX0.7Ls  
} 33{(IzL0  
catch(Exception e){e.printStackTrace ();} d=TZaVL$$  
} x tJ_azt  
7.r}98V  
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//获得文件长度 cPemrNxydN  
public long getFileSize() ;}t
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{ *6-fvqCv  
int nFileLength = -1; Zewx*Y|
 
try{ g`)5g5  
URL url = new URL(siteInfoBean.getSSiteURL()); lE8M.ho\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Vu%XoI)<KY  
httpConnection.setRequestProperty("User-Agent","NetFox"); vBMuVpzO  
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int responseCode=httpConnection.getResponseCode(); *q?-M"K  
if(responseCode>=400) f?ImQYqP
 
{ nZfU:N  
processErrorCode(responseCode); = }&@XRLJ  
return -2; //-2 represent access is error ]y4(WG;:  
} Bc/'LI.%  
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String sHeader; w/L^w50pt  
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for(int i=1;;i++) p m4g),s  
{ v{N4*P.0T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
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//Utility.log(in.readLine()); =aWj+ggd@  
sHeader=httpConnection.getHeaderFieldKey(i); [|=#~(yYQ  
if(sHeader!=null) ,s%1#cbR  
{ Y7vTs
eq  
if(sHeader.equals("Content-Length"))  Nn"[GB  
{ IZ$7'Mo86  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); BVKr
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break; pzo9?/-  
} >y2;sJ4]D%  
} SNV[KdvP*  
else uB(16|W>S  
break; x2#5"/~4  
} arCi$:-z@  
} 8sDbvVh1F  
catch(IOException e){e.printStackTrace ();} 23lLoyN  
catch(Exception e){e.printStackTrace ();} r((2.,\Z  
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Utility.log(nFileLength); d6$,iw@>^  
6,ZfC<)  
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return nFileLength; }@6/sg  
} `A]CdgA  
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yj^LX2x"  
//保存下载信息（文件指针位置） )yV|vn  
private void write_nPos() 19Cs 3B\4  
{ Vv
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try{ }Htnhom0n  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ){AtV&{$  
output.writeInt(nStartPos.length); pJ` M5pF  
for(int i=0;i<nStartPos.length;i++) ]x8_f6;D  
{ h,Y!d]2w  
// output.writeLong(nPos); L[]*vj   
output.writeLong(fileSplitterFetch.nStartPos); F:PaVr3q  
output.writeLong(fileSplitterFetch.nEndPos); u|!O
n  
} jRswGMx  
output.close(); &C~R*  
} CQf<En|1  
catch(IOException e){e.printStackTrace ();} 9`"o,wGX3  
catch(Exception e){e.printStackTrace ();} tQSj[Yl  
} Qy)+YhE  

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//读取保存的下载信息（文件指针位置） Zz"b&`K  
private void read_nPos() 7}r!&Eb  
{ ZP@or2No%  
try{ +d[A'&"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
*]ROUk@K=  
int nCount = input.readInt(); z (N3oBW  
nStartPos = new long[nCount]; QT1(= wK3  
nEndPos = new long[nCount]; }{! #`'s  
for(int i=0;i<nStartPos.length;i++) `EV"
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{ a@|/D\C  
nStartPos = input.readLong(); R^}}-Dvr  
nEndPos = input.readLong(); ]L'FYOfrpx  
} U({20  
input.close(); hEO#uAR^Z  
} ZS&n,<a5L}  
catch(IOException e){e.printStackTrace ();} -=W"  
catch(Exception e){e.printStackTrace ();} dXkgWLI~  
} :$bp4+
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private void processErrorCode(int nErrorCode) 2?",2x09  
{ "6T: &>  
System.err.println("Error Code : " + nErrorCode); 5ryzAB O\2  
} ?;{fqeJz  
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//停止文件下载 _%Hp
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public void siteStop() 81\$X  
{ '~dE0ohWb  
bStop = true; K3eYeXV  
for(int i=0;i<nStartPos.length;i++) MA:2]l3e  
fileSplitterFetch.splitterStop(); Hpo/CY/  
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} }uI(D&?+h  
} A),nkw0X  
//负责部分文件的抓取 so* lV  
**FileSplitterFetch.java GZL{~7n  
*/ NDG3mCl  
package NetFox; r]XXN2[jO  
5e!YYt>  
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import java.io.*; <Tq&Va_w  
import java.net.*; Sm(QgZO[4  
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public class FileSplitterFetch extends Thread { ~[@Gj{6p0  
bYr;~ ^  
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String sURL; //File URL sGNVZx  
long nStartPos; //File Snippet Start Position dg%Orvuz  
long nEndPos; //File Snippet End Position 9NH"Ik*  
int nThreadID; //Thread's ID 6E9y[ %+  
boolean bDownOver = false; //Downing is over <Sxsmf0"  
boolean bStop = false; //Stop identical >".,=u'  
FileAccessI fileAccessI = null; //File Access interface ]J^9iDTTA  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException P]bq9!{1  
{ %-~W|Y  
this.sURL = sURL; +39Vxe:Oy  
this.nStartPos = nStart; uV]4C^k;`[  
this.nEndPos = nEnd; ,hj5.;
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nThreadID = id; zVLv-U/=d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?[4!2T,Ca  
} Ua.7_Em  
U @Il:\I  
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public void run() 7wt2|$Qz  
{ #1MEmt  
while(nStartPos < nEndPos && !bStop) ,2F4S5F~rC  
{ s*R\!L  
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T-Od|T@[  
try{ xl%!7?G|$>  
URL url = new URL(sURL); s52c`+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); stnyJ9  
httpConnection.setRequestProperty("User-Agent","NetFox"); lO/<xSjNd  
String sProperty = "bytes="+nStartPos+"-"; Ol
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httpConnection.setRequestProperty("RANGE",sProperty); ?^z!yD\  
Utility.log(sProperty); ;H#'9p,2  
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InputStream input = httpConnection.getInputStream(); q% Eze  
//logResponseHead(httpConnection); ^}XKhn.S'  
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byte[] b = new byte[1024]; C;DNL^  
int nRead; Ep%5wR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) NIeKS_ +  
{ !HA[:-JCz  
nStartPos += fileAccessI.write(b,0,nRead); ;!<WL@C~  
//if(nThreadID == 1)
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RUTlwT
dv  
} h+mM  
t#+X*'/  
I)~&6@Jn  
Utility.log("Thread " + nThreadID + " is over!"); 15Vb`Vf`N  
bDownOver = true; #C?
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//nPos = fileAccessI.write (b,0,nRead); ^7`"wj14  
} 0_HdjK  
catch(Exception e){e.printStackTrace ();} 2e}${NZN  
} 9I>+Q&   
} Q]_3 #_'  
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V/Hjd`n)`i  
//打印回应的头信息 'hl>pso.  
public void logResponseHead(HttpURLConnection con) .BsZ.!MPL(  
{ eTI<WFRc_  
for(int i=1;;i++) b _fI1f|  
{ _A*5BAB:h(  
String header=con.getHeaderFieldKey(i); j
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if(header!=null) :sRV]!Iw  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); W1X\!Y  
Utility.log(header+" : "+con.getHeaderField(header)); Wjt1NfS&  
else `nccRy<l  
break; a^qLyF&F  
} \Q"o\:IoIT  
} DG8LoWZ  
>;',U<Wd  
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public void splitterStop() ?2VY^7N[  
{ i^9PiP|U  
bStop = true; v}hmI']yf  
} Dm/# \y3  
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} C+-GE9=  
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qr%9Sdvx  
/* "J]_B  
**FileAccess.java nAn/Vu  
*//文件访问(定位，写) .5I!h !  
package NetFox; 16MRLDhnD  
import java.io.*; f[3DK
A  
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^4^1)' %  
public class FileAccessI implements Serializable{ *>!O2c  
(#* 7LdZ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d%?+q0j  
RandomAccessFile oSavedFile; '1A S66k  
long nPos; g(t"+ P  
&
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public FileAccessI() throws IOException _[-+%RP  
{ IM&2SSmYNH  
this("",0); 3vPb}  
} $:"r$7  
SU;PmG4  
&^e%gU8!\  
public FileAccessI(String sName,long nPos) throws IOException #%k!`?^fbK  
{ *6~ODiB
  
oSavedFile = new RandomAccessFile(sName,"rw"); $X_JUzb  
this.nPos = nPos; @-bX[}.  
oSavedFile.seek(nPos); _^Lv8a3(O  
} ][-N<  
[-!   
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public synchronized int write(byte[] b,int nStart,int nLen) }}XYV eI  
{ e Ll+F%@  
int n = -1; !=@Lyt)_b  
try{ S!qJqZ<Bv  
oSavedFile.write(b,nStart,nLen); `k65&]&d  
n = nLen; *@fR36  
} e{8z1t20:  
catch(IOException e) T9]|*~ ,T  
{ a&~_ba+  
e.printStackTrace (); 3DnlXH(h1  
} 9^h\vR|]S  
}^WQNdws56  
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return n; Pk[:+. f(  
} vJDK]p<}  
obRR))  
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} !)RND 6.  
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/* X-9>;Mb~y  
**SiteInfoBean.java N-|E^XIV  
*/ Et
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package NetFox; *@=in7*c  
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MB :knj  
public class SiteInfoBean { cVJ
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private String sSiteURL; //Site's URL kA?a}  
private String sFilePath; //Saved File's Path Yu-e|:
 
private String sFileName; //Saved File's Name B7(~m8:eH7  
private int nSplitter; //Count of Splited Downloading File Q[_
{:DJA  
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public SiteInfoBean() sfi.zuG  
{//nSplitter的缺省值为5 <m9hM?^q  
//default value of nSplitter is 5 xy$73K6  
this("","","",5); b'Qia'a%  
} | 2BIAm]  
q%TWtQS  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [hA%VF.9  
{ "l!WO`.zp=  
sSiteURL= sURL; M3@Wb@  
sFilePath = sPath; Hrq1{3~  
sFileName = sName; ^]w!ow41  
this.nSplitter = nSpiltter; y:(OZ%g  
;vvO#3DWM  
24PEt%2  
} ,80qwN,  
/e :V44  
7l> |G,[c  
public String getSSiteURL() D].!u{##  
{ T:q_1W?h]  
return sSiteURL; YO7Y1(`  
} Wr Ht  
BDSZ'  
){`s&?M0  
public void setSSiteURL(String value) Kk1591'  
{ HQ~`ha.  
sSiteURL = value; %JM:4G|q  
} ~K}iVX  
$2qZds[  
R06L4,/b  
public String getSFilePath() }S51yDVG_  
{ bVmHUcR0  
return sFilePath; 6nh!g  
} |niYN7 17  
dfY(5Wc+f  
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public void setSFilePath(String value) c7Sa|9*dR  
{ b/'{6zn  
sFilePath = value; 3~Od2nk(x  
} uc!j`G*]  
S9R(;  
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public String getSFileName() X.hU23w  
{ :)VO,b~r  
return sFileName; lxb+
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} e5G)83[=  
yG\^PD  
)9F-h8 &"  
public void setSFileName(String value) 6yk=4l\  
{ 51j5AbFQ"  
sFileName = value; LVKvPi  
} 4k/B=%l  
[xzgk[>5  
g^|}e?  
public int getNSplitter() _+PiaJ&'  
{ T<(1)N1H`  
return nSplitter; #\s*>Z  
} .[&0FHnJ5  
ap=m5h27  
~_opU(;f  
public void setNSplitter(int nCount) aX`"V/  
{ +v.uP[H  
nSplitter = nCount; {<&i4;
 
} @_s`@,=  
} Ie{98  
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#HFB*>  
/* p=%Vo@*]  
**Utility.java s}Phw2`1U  
*/ y4*i V;"  
package NetFox; 8*7t1$  
.4on7<-a  
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public class Utility { Pyh+HD\  
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.nN=M>#/  
public Utility() ?>c*[>LpZ  
{ x`T  
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6  
} sd4eJ  
X`#,*HkK  
//线程睡眠 oSVo~F  
public static void sleep(int nSecond) @>`+eg][?P  
{ <vMna< /d  
try{ K$v SdpC  
Thread.sleep(nSecond); .{+KKa $@G  
} xz2U?)m;x  
catch(Exception e) 9V
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{ PdiP5S }/
 
e.printStackTrace (); .T~<[0Ex+U  
} =k.:XblEe[  
}
Ed
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,fWQSc\}  
//日志 ;W%nB
dE6|  
public static void log(String sMsg) (NfP2E|B  
{ tUX4#{)q(j  
System.err.println(sMsg); ycYT1Sg8  
} 2iOn\ ^]x  
1ocd$)B|}  

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public static void log(int sMsg) :QKxpHi  
{ ^n8ioL\*i  
System.err.println(sMsg); AI KLJvte  
} -& Qm"-?:  
} t^_0w[  
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MTBHFjXO  
/* k3[rO}>s  
**TestMethod.java u.v 5!G  
*/ _N8Tu~lqV  
package NetFox; *R9s0;&:  
G!]%xFwYa  
,RmXZnWY  
public class TestMethod { h>ZNPP8N  
Oi#4|*b{W  
]vj.s/F~  
public TestMethod() 758`lfz=_  
{ ///xx/weblogic60b2_win.exe nW)-bAV<  
try{ U@t"o3E  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %=p:\+`VI  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^gw htnI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); b"D? @dGB,  
fileFetch.start(); tG8)!  
} Ah^0FU%!g  
catch(Exception e){e.printStackTrace ();} feJzX*u  
%v}SJEXFp  
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} 'XW[uK]w)  
>?Y)evW  
05
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public static void main(String[] args) Z_b^K^4  
{ 1XfH,6\8i  
new TestMethod(); {u!Q=D$3  
} L'i0|_  
} eAqSY s!1  
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