http断点续传简单实现（java)

/* D\^mh{q(  
**SiteFileFetch.java +iqzj-e&e[  
*/ 4|&_i)S-Y  
package NetFox; ::p%R@?  
import java.io.*; QE|x[?7e,!  
import java.net.*; 7@R^B=pb  
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public class SiteFileFetch extends Thread { 0.\}D:x(z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean K=! C\T"I%  
long[] nStartPos; //开始位置  :yw8_D3  
long[] nEndPos; //结束位置 "!Qi$ ]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b@S~ =  
long nFileLength; //文件长度 D GL=\  
boolean bFirst = true; //是否第一次取文件 wg+[T;0S  
boolean bStop = false; //停止标志 j#~ S"t  
File tmpFile; //文件下载的临时信息 XRmE  
DataOutputStream output; //输出到文件的输出流 \_(|$Dhq  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 0.S7uH%
"  
public SiteFileFetch(SiteInfoBean bean) throws IOException C#V_Gb  
{ 4T6: C?V  
siteInfoBean = bean; 0GW69 z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5yyc0UG  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F}.R-j#  
if(tmpFile.exists ()) ;}lsD1S:  
{ J%]5C}v \  
bFirst = false; )<%CI#s#  
read_nPos(); ^-LnO%h?  
} n&!q9CR`  
else ~Ede5Vg!!2  
{ #@' B\!<@=  
nStartPos = new long[bean.getNSplitter()]; JXjH}C  
nEndPos = new long[bean.getNSplitter()]; ^RE[5h6^q  
} 4k9$' k  
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} t7yvd7  
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public void run() I s|_  
{ ~z^49Ys:  
//获得文件长度 ;?q-]J?  
//分割文件 j115:f  
//实例FileSplitterFetch 9K;g\? 3  
//启动FileSplitterFetch线程 F~0iJnF  
//等待子线程返回 M6ZXq6J  
try{ >;]S+^dXY  
if(bFirst) H
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{ i%GiWanG  
nFileLength = getFileSize(); Z`f?7/"B  
if(nFileLength == -1) /U,(u9bq  
{ uaYI3w@^  
System.err.println("File Length is not known!"); F >H\F@Wl  
} Wv%F^(R7  
else if(nFileLength == -2) DQ}&J  
{ o=RxQk1N  
System.err.println("File is not access!"); TV|Z$,6l  
} r:PYAb=g  
else 37biRXqLH  
{ aTfc>A;  
for(int i=0;i<nStartPos.length;i++) .:XXc  
{ ~1XC5.*-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); nI4oQE  
} z0x^HDAeC  
for(int i=0;i<nEndPos.length-1;i++) ^?_MIS`4N  
{ h@]{j_$u  
nEndPos = nStartPos[i+1]; CfO{KiM(2  
} P'SGt  
nEndPos[nEndPos.length-1] = nFileLength; z}iz~WZ  
} <>(v~a]  
} M1]w0~G  
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//启动子线程 k.})3~F-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nltOX@P-  
for(int i=0;i<nStartPos.length;i++) U\W$^r,  
{ 1cx%+-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TD-B\ @_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), P)LQ=b}V#;  
nStartPos,nEndPos,i); wz
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,gW$m
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fileSplitterFetch.start(); '"XVe+.O  
} P9R-41!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |z8_]o+|r1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); C8do8$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", eY%Ep=J  
nEndPos = " + nFileLength); JvEW0-B^l,  
// fileSplitterFetch[nPos.length-1].start(); 3UF^Ff<wo  
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//等待子线程结束 O$x +>^  
//int count = 0; xnJ#}-.7  
//是否结束while循环
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boolean breakWhile = false; aO}p"-'  
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while(!bStop) rLY I\  
{ I.Xbowl  
write_nPos(); Hq~SRc~  
Utility.sleep(500); ?r*}1WsH  
breakWhile = true; 'R2*3<  
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for(int i=0;i<nStartPos.length;i++) Ted tmX$  
{ <WbO&;%  
if(!fileSplitterFetch.bDownOver) S;/pm$?/  
{ !]9qQ7+R%  
breakWhile = false; yRDtPK"E-  
break; O'(D:D?  
} s'd\"WaQV  
} 6;@:/kl t  
if(breakWhile) _RS CyV  
break; f =A#:d  
\ [M4[Qlq  
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//count++; [w-# !X2y  
//if(count>4) ?!$Dr0r  
// siteStop(); 0'Qvis[kt  
} dtjb(*x  
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System.err.println("文件下载结束！"); !HtW~8|:  
} oA:`=f%\  
catch(Exception e){e.printStackTrace ();} GO*D4<#u  
} BlM(
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//获得文件长度 5E 9
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public long getFileSize() Bk@EQdn  
{ pcQkJF  
int nFileLength = -1; jwuSne  
try{ {9) 
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URL url = new URL(siteInfoBean.getSSiteURL()); {%RwZ'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ooCfr?E  
httpConnection.setRequestProperty("User-Agent","NetFox"); b\kA  
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int responseCode=httpConnection.getResponseCode(); Eg2SC?5
 
if(responseCode>=400) {lUaN0O:  
{ Z0v&AD=  
processErrorCode(responseCode); &T ^bv*P  
return -2; //-2 represent access is error %  .ss  
} '|*e4n  
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_ /Eg_dQ~@  
String sHeader; e2>AL  
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for(int i=1;;i++) .81 ~ K[  
{ ~]9EhC'l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %h;1}SFl0  
//Utility.log(in.readLine()); TTWiwPo59  
sHeader=httpConnection.getHeaderFieldKey(i); |+JC'b?,  
if(sHeader!=null) ccx0aC3@I  
{ bj_/  
if(sHeader.equals("Content-Length")) Z.rhM[*+0C  
{ >z%WW&Z'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~BE=z:  
break; :~ &#9  
} tO D}&  
} fQ-IM/z  
else *+00  
break; oMYZ^b^  
} ixoN#'y<"  
} 7{k?"NF  
catch(IOException e){e.printStackTrace ();} SL\15`[{  
catch(Exception e){e.printStackTrace ();} fP8bWZ{  
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Utility.log(nFileLength); SLH;iqPT  
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return nFileLength; u6:$AA  
} +1\t0P24  
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)  
//保存下载信息（文件指针位置） T{N8 K K  
private void write_nPos() *iyc,f^w  
{ jR+kx:+  
try{ NSR][h_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #BgiDLh  
output.writeInt(nStartPos.length); +CXq41g"c  
for(int i=0;i<nStartPos.length;i++) {d)L0KXK  
{ hvA|d=R(  
// output.writeLong(nPos); m%.[|sZ3EM  
output.writeLong(fileSplitterFetch.nStartPos); gO@LJ  
output.writeLong(fileSplitterFetch.nEndPos); uu>R)iTQ%S  
} Zw<<p|{)<  
output.close(); ?+%bEZ`  
} N| P?!G-=  
catch(IOException e){e.printStackTrace ();} FF|M7/[~  
catch(Exception e){e.printStackTrace ();} [o7Qr?RN  
} =+[`9  
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//读取保存的下载信息（文件指针位置） tbfwgK
 
private void read_nPos() 6uk}4
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{ TQ%F\@"  
try{ %ZDO0P !/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); sWKdqs  
int nCount = input.readInt(); =8"xQ>D62  
nStartPos = new long[nCount]; r029E-  
nEndPos = new long[nCount]; 0< }BSv  
for(int i=0;i<nStartPos.length;i++) ,,Ivey!kL  
{ YOA)paq+  
nStartPos = input.readLong(); ?V(+Cc  
nEndPos = input.readLong(); 6!;D],,"#.  
} k\g:uIsv$  
input.close(); vWL|vR  
} ZG~d<kM&8s  
catch(IOException e){e.printStackTrace ();} 9ESV[  
catch(Exception e){e.printStackTrace ();} .&8a ;Q?c  
} $ERiBALN:  
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private void processErrorCode(int nErrorCode) UA*Kuad  
{ ep*8*GmP  
System.err.println("Error Code : " + nErrorCode); FMWM:  
} ,#%I$  
l|;]"&|_]c  
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//停止文件下载 _?eT[!oO8  
public void siteStop() aB`jFp-  
{ T#[#w*w/  
bStop = true; R D?
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for(int i=0;i<nStartPos.length;i++)  NfmHa  
fileSplitterFetch.splitterStop(); $s 'n]]Wq  
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} C5e;U  
} 7*He 8G[W  
//负责部分文件的抓取 =j{Kxnv  
**FileSplitterFetch.java 3~Ap1_9  
*/ ["<'fq;PJ  
package NetFox; #%V+- b(  
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import java.io.*; LyL(~Jc|  
import java.net.*; ktp<o.f[  
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public class FileSplitterFetch extends Thread { g0-rQ
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String sURL; //File URL wyLyPJv  
long nStartPos; //File Snippet Start Position \eRct_  
long nEndPos; //File Snippet End Position Nx E=^ v  
int nThreadID; //Thread's ID QUh`kt(E  
boolean bDownOver = false; //Downing is over .8;0O M  
boolean bStop = false; //Stop identical "^Y zHq6  
FileAccessI fileAccessI = null; //File Access interface P'*Fd3B#A=  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \5Y<UJKi  
{ da@W6Ovx  
this.sURL = sURL; 2(Aw  
this.nStartPos = nStart; GR_caP  
this.nEndPos = nEnd; n9-WZsc1  
nThreadID = id; vF/wV'Kk  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 e0<O6  
} nyBT4e  
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public void run() yD@eT:lyi  
{ 5du xW>D  
while(nStartPos < nEndPos && !bStop) fVdu9 l  
{ eo.B0NZsF  
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try{ J"TF@7{p  
URL url = new URL(sURL); X}g3[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,,BWWFg~  
httpConnection.setRequestProperty("User-Agent","NetFox"); w6pXF5ur>  
String sProperty = "bytes="+nStartPos+"-"; 3e1P!^'\  
httpConnection.setRequestProperty("RANGE",sProperty); w"?RbA  
Utility.log(sProperty); LC\U6J't1  
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InputStream input = httpConnection.getInputStream(); <d >!%  
//logResponseHead(httpConnection); QX-n l~  
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byte[] b = new byte[1024]; pbw{Ez
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int nRead; {-%8RSK=<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) z%\&n0  
{ e^$JGh2  
nStartPos += fileAccessI.write(b,0,nRead); ]b:>7_la  
//if(nThreadID == 1) 9Hd_sNUu\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y*p02\)  
} IIAmx[ b  
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Utility.log("Thread " + nThreadID + " is over!"); 2(m#WK7>F  
bDownOver = true; sz%_9;`dpL  
//nPos = fileAccessI.write (b,0,nRead); mkl^2V13~  
} cv7:5P  
catch(Exception e){e.printStackTrace ();} C2\zbC[qm  
} A~ _2"  
} *N"CV={No  
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//打印回应的头信息 <XN=v!2;  
public void logResponseHead(HttpURLConnection con) NCl@C$W
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{ d`~~Ww1  
for(int i=1;;i++) n 8 K6m(  
{ E%Ww)P  
String header=con.getHeaderFieldKey(i); 
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if(header!=null) 0=K8 nxdx  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); MH9vg5QKp  
Utility.log(header+" : "+con.getHeaderField(header)); TPak,h(1  
else ww #kc!'  
break; Ivj=?[c|  
} 4I&Mdt<^D  
} u8M_2r  
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 WjCxTBI  
public void splitterStop() A7|L|+ ?  
{
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bStop = true; /bPs0>5  
} G=SMz+z  

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}
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-
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/* Ez-Q'v(9  
**FileAccess.java ge<D}6GQ  
*//文件访问(定位，写) ._Ww  
package NetFox; _l"nwE
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import java.io.*; SD<a#S\o  
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public class FileAccessI implements Serializable{ Ks@cwY  
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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 Vu=/<;-N  
RandomAccessFile oSavedFile; C,GZ  
long nPos; t,IOq[Vtk  
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public FileAccessI() throws IOException qZ&~&f|>e  
{ v^vi *c  
this("",0); 4d-(:  
} ODhq `?(N  
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public FileAccessI(String sName,long nPos) throws IOException x~wS/y  
{ -a&<Un/  
oSavedFile = new RandomAccessFile(sName,"rw"); 4e#$-V   
this.nPos = nPos; w6WPfy(/2  
oSavedFile.seek(nPos); )%3T1 D/  
} j@D,2B;  
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public synchronized int write(byte[] b,int nStart,int nLen) qb/}&J7+  
{ o. ;Vrc  
int n = -1; ^_<|~  
try{ o:fe`#t  
oSavedFile.write(b,nStart,nLen); RAP-vVh/C  
n = nLen; y&-QLX L  
} nosD1sS.K8  
catch(IOException e) B4wRwrVI>  
{ [~2imS  
e.printStackTrace (); j49Uj}:j  
} $LFL4Q  
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return n; J9p4\=9  
} H;l_;c`  
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} m!ueqV"  
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/* Z0m`%(MJa  
**SiteInfoBean.java sA77*T  
*/ v{fcQb  
package NetFox; ii-AE L  
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public class SiteInfoBean { ne/JC(  
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private String sSiteURL; //Site's URL $2L6:&.P,  
private String sFilePath; //Saved File's Path 6CIzT.  
private String sFileName; //Saved File's Name -p.\fvip  
private int nSplitter; //Count of Splited Downloading File ZcQu9XDIt  
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public SiteInfoBean() n=vDEX:'  
{//nSplitter的缺省值为5 *{!Y_FrL  
//default value of nSplitter is 5 hW<v5
!,  
this("","","",5); "cPg_-n  
} z+yIP ?s}(  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) O6R)>Y4  
{ |f#hGk6  
sSiteURL= sURL; pX?3inQP%(  
sFilePath = sPath; v/.'st2%  
sFileName = sName; f,KB BBbG  
this.nSplitter = nSpiltter; cN8Fn4g
q  
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} %gh#gH  
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public String getSSiteURL() oDz|%N2s|  
{ DylO;+  
return sSiteURL; C;N6",s!  
} YAOfuas]j  
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public void setSSiteURL(String value) YcN|L&R.  
{ E,}{iqAb  
sSiteURL = value; 7|DG1p9C  
} v{VF>qEP  
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public String getSFilePath() Gl1XRNyC  
{ 6FA+qYSV  
return sFilePath; o8 JOpD  
} <$0is:]  
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public void setSFilePath(String value) dm4Q'u
 
{ ` 3qf}=Z`  
sFilePath = value; <m]0!ii  
} d-D,Gx]>$  
yx :^*/  
ZH_$Q$9  
public String getSFileName() (?7=,A7^  
{ ^w60AqR8  
return sFileName; oLT#'42+H  
} L7-BuW}&  
1 :p'  
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public void setSFileName(String value) >v.fH6P,}  
{ Sfz1p  
sFileName = value; +[!S[KE  
} S\g9@g.  
I'
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73;Y(uh9  
public int getNSplitter() Q[biy{(b8  
{ Jr2yn{s=S  
return nSplitter; ^v'kEsE^*  
} CUu Owx6%  
4XjwU`  
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public void setNSplitter(int nCount) .h-mFcjy  
{ FvpU]
 
nSplitter = nCount; ^l!SIu  
}  3%kUj  
} 4>*=q*<V5E  
.| 4P :r  
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/* "?NDN4l*  
**Utility.java s6,~JF^  
*/ WigtTAh4  
package NetFox; bC `<A  
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public class Utility { $0_K&_5w~  
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public Utility() yE8D^M|g  
{ !kovrvM6F  
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} d`^3fr'.4A  
J:@gmo`M;V  
//线程睡眠 |g&V? lI  
public static void sleep(int nSecond) Lv%3 jj  
{ {N4 'g_  
try{ 4z0gyCAC A  
Thread.sleep(nSecond); .l1
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} NnLK!Q  
catch(Exception e) [ohLG_9  
{ FS1\`#Bm)  
e.printStackTrace (); 0cS$S Mn{  
} %R0 Wq4}  
} Hd~g\  
Lh[0B.g<  
//日志 ihrf/b  
public static void log(String sMsg) fDy*dp4z  
{ uy{O  
System.err.println(sMsg); Hr?lRaV  
} A8'RM F1  
^Arv6kD,  
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public static void log(int sMsg) tbS hSbj  
{ Cn~VJ,l g  
System.err.println(sMsg); LYDiqOrx  
} 4 Ej->T.  
} TKB8%/_p  
n _K1%  
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/* c4fH/-  
**TestMethod.java YV.' L  
*/ *yhA8fJ  
package NetFox; Z@zo~*o  
v"k ?e  
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public class TestMethod { :uCwWv  
EO!,rB7I  
w6vbYPCN  
public TestMethod() KuJ)alD;1  
{ ///xx/weblogic60b2_win.exe }4C_r'd6  
try{  S_P&Fv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6>]_H(z7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V4,Gt]4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); rfwJLl/  
fileFetch.start(); )\1>)BJq  
} ~B;}jI]d[  
catch(Exception e){e.printStackTrace ();} w%])  
(<Cq_Kw  
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} )E9!m  
2.v{W-D[  
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public static void main(String[] args) jEBn"]\D  
{ q;eb  
new TestMethod(); |5~Oh`w  
} rI$NNk'A  
} >?^oxB"<Gc  
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