http断点续传简单实现（java)

/* Upl6:xYrG  
**SiteFileFetch.java $L4/I!Yf  
*/ B=L&bx  
package NetFox; ~0"p*?
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import java.io.*; N8cAqr  
import java.net.*; 5}ie]/[|  
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public class SiteFileFetch extends Thread { Uh}seB#mJj  
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SiteInfoBean siteInfoBean = null; //文件信息Bean wJb#
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long[] nStartPos; //开始位置 pVp:@0h  
long[] nEndPos; //结束位置 `i~ Y Fr  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x LBQ  
long nFileLength; //文件长度 6Sj6i^"  
boolean bFirst = true; //是否第一次取文件 Cm$1$?J  
boolean bStop = false; //停止标志 +#@"*yj3  
File tmpFile; //文件下载的临时信息 }0hL~i  
DataOutputStream output; //输出到文件的输出流 N<|$h5isq  
2g{)AtK$#  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） vY|^/[x#B  
public SiteFileFetch(SiteInfoBean bean) throws IOException p4>$z& _  
{ #h!*dj"  
siteInfoBean = bean; 9ch#}/7B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Z[!d*O%R_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ey{%XR+*;  
if(tmpFile.exists ()) 1iT\df  
{ k#TYKft  
bFirst = false; %WG9 dYdS  
read_nPos(); 31+;]W=  
} {Ee>n^1  
else v;#=e$%}MO  
{ {@}?k s5  
nStartPos = new long[bean.getNSplitter()]; .Jb$l$5'w  
nEndPos = new long[bean.getNSplitter()]; .V9e=yW!*  
} zboF 1v`  
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} gQSNU_o Z  
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public void run() _?7#MWe&  
{ C9n}6Er=,  
//获得文件长度 >C WKH~  
//分割文件 5(2|tJw-H;  
//实例FileSplitterFetch "bg'@:4F  
//启动FileSplitterFetch线程 3LR p2(A  
//等待子线程返回 ;Lw{XqT  
try{ f"#m=_Xm  
if(bFirst) ? ]sM8Bd}  
{ 9n]|PE
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nFileLength = getFileSize(); p5=|Y^g !  
if(nFileLength == -1) D*5hrkV9  
{ sGDV]~E  
System.err.println("File Length is not known!"); +eQe%U  
} fHrt+_Zn|  
else if(nFileLength == -2) 6}~pq1IF{  
{ >e5 *p
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System.err.println("File is not access!"); !U_K&f  
} -
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else $$i.O}  
{ .o%^'m"=D[  
for(int i=0;i<nStartPos.length;i++) 7x]4`#u  
{ Sydh2d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,7Y-k'7Kop  
} @4~=CV%j  
for(int i=0;i<nEndPos.length-1;i++) Dq\ Jz~  
{ V{-AP=C7  
nEndPos = nStartPos[i+1]; |XY
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} eC DIwB28  
nEndPos[nEndPos.length-1] = nFileLength; 8GPIZh'0h  
} \2[<XG(^  
} T
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//启动子线程 js^ ,(CS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; o 6{\Zzp  
for(int i=0;i<nStartPos.length;i++) Bsf7mcXz7z  
{ p]D]: Z}P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4!62/df  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), yn AB  
nStartPos,nEndPos,i); +j+5ud`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); uxn)R#?  
fileSplitterFetch.start(); kEeo5XN  
} e;bYaM4UX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Mpue   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Mvj;ic6iK  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H?1xjY9sl  
nEndPos = " + nFileLength);
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// fileSplitterFetch[nPos.length-1].start(); *F^wtH`  
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4rK{-jvh>m  
//等待子线程结束 D(W,yq~7uY  
//int count = 0; `Ycf]2.,$
 
//是否结束while循环 +1JH  
boolean breakWhile = false; p1pQU={<  
u*S=[dq  
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while(!bStop) V~DMtB7  
{ Xm2\0=v5;  
write_nPos(); 8VG!TpX/B  
Utility.sleep(500); 5FVndMM#y  
breakWhile = true; :%&Q-kk4!  
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for(int i=0;i<nStartPos.length;i++) 5[l8y,  
{ a?} .Fs  
if(!fileSplitterFetch.bDownOver) zIC;7 5#  
{ E9\vA*a  
breakWhile = false; ;DA8B'^>  
break; e<7.y#L  
} p;)"  
} %)jxW
{  
if(breakWhile) rVvR!"//yH  
break; \?>Hu v  
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//count++; U/ V  
//if(count>4) CfEmT8sa  
// siteStop(); CHd9l]Rbe  
} 4!Z5og1kn  
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5IOFSy`  
System.err.println("文件下载结束！"); #?MY&hdU9  
} -\ZcOXpMx=  
catch(Exception e){e.printStackTrace ();} 5*PYT=p}  
} `0H g y=  
7*Qk`*Ii  
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//获得文件长度 $CTSnlPq  
public long getFileSize() *b *G2f^  
{ 682Z}"I0  
int nFileLength = -1; eg<bi@C1|  
try{ # ,uya2!)  
URL url = new URL(siteInfoBean.getSSiteURL()); %98' @$:0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &wd;EGGT!q  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]Y6cwZOe  
R_]{2~J+  
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int responseCode=httpConnection.getResponseCode(); %:>3n8n  
if(responseCode>=400) 1"8yLvtn  
{ sb:d>6  
processErrorCode(responseCode); :.(;<b<\  
return -2; //-2 represent access is error ]A FI\$qB\  
} dpQG[vXe  
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String sHeader; -yxOBq  
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for(int i=1;;i++) Qjx?ri//  
{ s?8<50s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9[!,c`pw  
//Utility.log(in.readLine()); f~E*Zz`;  
sHeader=httpConnection.getHeaderFieldKey(i); MRU7W4W-~/  
if(sHeader!=null) G;> _<22  
{ I8oo~2Qw  
if(sHeader.equals("Content-Length")) }:: S0l  
{ umz;F  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 01!s"wjf  
break; `[o)<<}  
} \ w3]5gJZ  
} l4T7'U>`  
else mw_Ew]&  
break; =U|N=/y#hJ  
} Y`+=p@2O2o  
} '`'GK&)  
catch(IOException e){e.printStackTrace ();} yA{W  
catch(Exception e){e.printStackTrace ();} Q1V9PRZX
 
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Utility.log(nFileLength); H>r!i4l  
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return nFileLength; &A#~)i5gF  
} MX>[^
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,C3,TkA]  
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//保存下载信息（文件指针位置） KfF!{g f  
private void write_nPos() 12Y  
{ HF|oBX$_  
try{ ZiLj=bh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Dk48@`l2  
output.writeInt(nStartPos.length); \EseGgd21  
for(int i=0;i<nStartPos.length;i++) ETs>`#`6o  
{ r$)w7Gk<  
// output.writeLong(nPos); ">?vir^  
output.writeLong(fileSplitterFetch.nStartPos); <\?wAjc,  
output.writeLong(fileSplitterFetch.nEndPos); 26CS6(sn  
} 6(PM'@i  
output.close(); 0'nikLaKy  
} tHLrhH<w  
catch(IOException e){e.printStackTrace ();} &/,|+U[  
catch(Exception e){e.printStackTrace ();} \9-"M;R.d  
} G:g69=x y  
 Q1@A2+ c  
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//读取保存的下载信息（文件指针位置） |7x\m t  
private void read_nPos() yA47"R  
{ 2wF8 P)  
try{ vv26I  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "Ks,kSEzu  
int nCount = input.readInt(); :1Sl"?xU  
nStartPos = new long[nCount]; {k rswh3  
nEndPos = new long[nCount]; ;#Q%j%J  
for(int i=0;i<nStartPos.length;i++) 3_A *$  
{ hMtf.3S7c  
nStartPos = input.readLong(); 86nN"!{l:  
nEndPos = input.readLong(); arf8xqR-U]  
} +^;JS3p@\  
input.close(); <$JaWL  
} s(W|f|R  
catch(IOException e){e.printStackTrace ();} +{
/  
catch(Exception e){e.printStackTrace ();} g}]t[}s1]  
} # W"=ry3{  
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private void processErrorCode(int nErrorCode) 1'?4m0W1  
{ R:B^  
System.err.println("Error Code : " + nErrorCode); qe5feky  
} J=/5}u_gw  
*2jK#9"MP  
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//停止文件下载  T Q,?>6n  
public void siteStop() Dd`Mv$*d8  
{ &r:7g%{n  
bStop = true; /Z7iLq~t"G  
for(int i=0;i<nStartPos.length;i++) }f2r!7:x  
fileSplitterFetch.splitterStop(); U(x]O/m  
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} .9.2Be  
} r(9~$_(vK  
//负责部分文件的抓取 XVU2T5s}  
**FileSplitterFetch.java z?35=%~w   
*/ (y^vqMz  
package NetFox; 1)Zf3Y8  
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import java.io.*; K$d$m <  
import java.net.*; hJPlq0C  
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public class FileSplitterFetch extends Thread { 13Lr}M&  
%iw3oh&Fkm  
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String sURL; //File URL uG
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long nStartPos; //File Snippet Start Position MHa#?Q9  
long nEndPos; //File Snippet End Position Dih3}X&jn$  
int nThreadID; //Thread's ID {AQ=<RDRF  
boolean bDownOver = false; //Downing is over 33}oO,}t,  
boolean bStop = false; //Stop identical U,LTVYrO  
FileAccessI fileAccessI = null; //File Access interface %Rsp;1Z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7VP32Eh[  
{ +]Y,
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this.sURL = sURL; Tyck/ EO  
this.nStartPos = nStart; $kQ~d8 O  
this.nEndPos = nEnd; eY e,r  
nThreadID = id; nl9P, d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,UuH}E  
} CJhL)0Cs  
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public void run() [pM V?a[  
{ a`0=AQ  
while(nStartPos < nEndPos && !bStop) [ Fz`D/  
{ 4!wR_@W^El  
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try{ Sfr&p>{,  
URL url = new URL(sURL); @/1w4'M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iJ~Vl"|m  
httpConnection.setRequestProperty("User-Agent","NetFox"); GQ-Rtn4v  
String sProperty = "bytes="+nStartPos+"-"; nWHa.H#  
httpConnection.setRequestProperty("RANGE",sProperty); =lpQnj
"  
Utility.log(sProperty); @K!&qw  
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InputStream input = httpConnection.getInputStream(); <wAFy>7  
//logResponseHead(httpConnection); 8}(]]ayl  
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byte[] b = new byte[1024]; :GJ &_YHf  
int nRead; F,'exuZ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b3VS\[p  
{ -neKuj  
nStartPos += fileAccessI.write(b,0,nRead); uAWM\?  
//if(nThreadID == 1) 
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `Ry]y"K  
} LupkrxV  
:Q@&5!]>d  
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Utility.log("Thread " + nThreadID + " is over!"); b4pm_Um  
bDownOver = true; =ha{Ziryo  
//nPos = fileAccessI.write (b,0,nRead); *2X0^H|dS  
} 3=L.uXVb  
catch(Exception e){e.printStackTrace ();} +j4"!:N}B  
} 'f?$"U JF  
} {.?/)  
71{p+3Z&  
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//打印回应的头信息 NrJKbk^4u/  
public void logResponseHead(HttpURLConnection con) R`~z0d.  
{ 9cj9SB4  
for(int i=1;;i++)
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{ %?Ev|:i`@  
String header=con.getHeaderFieldKey(i); ~T89_L  
if(header!=null) @qHNE,K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~b2wBs)r  
Utility.log(header+" : "+con.getHeaderField(header)); ,zTy?OQ  
else #KiRfx4G  
break; +) m_o"hl  
} Pp5^@A  
} lO_UPC\@fw  
$-*!pRaVU  
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public void splitterStop() h?azFA~  
{ C;vtY[}<  
bStop = true; xoR;=ph  
} bv*,#Qm  
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} 2Roc|)-47  
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/* Xqm:
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**FileAccess.java 'uxX5k/D@t  
*//文件访问(定位，写) _> *jH'  
package NetFox; ~7Tc$ "I  
import java.io.*; 8M`#pN^  
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'>rw(3  
public class FileAccessI implements Serializable{ ^!by3Elqqk  
+@/"%9w
 
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 S9",d~EM  
RandomAccessFile oSavedFile; 8zR~d%pK  
long nPos; k'5?M  
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public FileAccessI() throws IOException fOMW"myQ  
{ 9b*nLyYVz  
this("",0); a)'5Nw9*  
} %&Q$dzgb_  
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4sT88lG4n  
public FileAccessI(String sName,long nPos) throws IOException HZf/CE9T  
{ '4#}e[e  
oSavedFile = new RandomAccessFile(sName,"rw"); +qwjbA+  
this.nPos = nPos; L-k@-)98  
oSavedFile.seek(nPos); ynhmMy%  
} V:c;-)(  
"PpN0Rr  
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public synchronized int write(byte[] b,int nStart,int nLen) Oal3rb  
{ Q{lpKe0  
int n = -1; OUNd@o  
try{ ^cz(}N 6&  
oSavedFile.write(b,nStart,nLen); #Q`dku%V:  
n = nLen; >b{q.  
} %eO0wa$a  
catch(IOException e) ]3l
9:|  
{ k>g_Z`%<  
e.printStackTrace (); !GNBDR
r  
} EG=Sl~~o  
H,u<|UMM_  
eF3,2DDC  
return n; nPy$D-L,  
} _<OSqE  
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uD@#
 
} lH6OcD:kj  
+P`*kj-P\  
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/* Yd~X77cv  
**SiteInfoBean.java F ;2w1S^  
*/ cj'}4(  
package NetFox; ]n~ilS.rkl  
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public class SiteInfoBean { <t \H^H!  
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private String sSiteURL; //Site's URL LBa[:j2  
private String sFilePath; //Saved File's Path 3 C<L  
private String sFileName; //Saved File's Name cZ2kYn8  
private int nSplitter; //Count of Splited Downloading File [CXrSST")E  
?3.b{Cq{-  
j?x>_#tIY  
public SiteInfoBean() +yD`3` E  
{//nSplitter的缺省值为5 <,e+ kL{  
//default value of nSplitter is 5 "\o+v|;  
this("","","",5); -RvQB  
} cLsV`@J(k  
m1Mt#@,$  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n' q4  
{ S9~+c  
sSiteURL= sURL; &b%zQ4%d-`  
sFilePath = sPath; PC-"gi=h  
sFileName = sName; +2&@x=xy  
this.nSplitter = nSpiltter; 3GhRWB-U  
!~rY1T~  
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} f m)pulz  
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public String getSSiteURL() J2xw) +  
{ ~ijVmWNk  
return sSiteURL;
B=^)Ub5'  
} hUp.tK:X7o  
!FElW`F  
[k;\SXDZo  
public void setSSiteURL(String value) w"c
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{ IV\'e}  
sSiteURL = value; }n3/vlW9  
} <4g{ fT0  
G(G{RAk>  
#\ X#w<\?  
public String getSFilePath() 8L:ji,"  
{ C,ARXW1  
return sFilePath; \1fN0e  
} hM6PP7XH  
@W[f1  
,>0*@2
 
public void setSFilePath(String value) eQp4|rf  
{ KmA;HiH%J  
sFilePath = value; $+Z)  
} "2)H'<  
]dGw2y  
lTV'J?8!-a  
public String getSFileName() \%f q  
{ uF9C-H@:  
return sFileName; 8T!+ZQAz  
} QSszn`e  
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4GY[7^  
public void setSFileName(String value) Rld!,t  
{ y)W@{@{kl  
sFileName = value; qQ?"@>PALD  
} -y8`yHb_  
=E.t`x=  
]%wVHC  
public int getNSplitter() N`L0Vd  
{ =WyZX 7@R  
return nSplitter; Z\ja  
}
ebUBrxZX  
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public void setNSplitter(int nCount) #t:S.A@  
{ XBb~\p3y  
nSplitter = nCount; HUv/ ~^<  
} C9n?@D;S  
} }%'?p<^M  
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/* g1W.mAA3B  
**Utility.java #><.oreXq  
*/ V-Sd[  
package NetFox; h?BFvbAt  
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public class Utility { ?fUlgQ}N  
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public Utility() V )x$|!(  
{ D6>2s\:>vp  
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\]2]/=2tLd  
} \Zqng  
naYrpK,.  
//线程睡眠 YaKeq5%y  
public static void sleep(int nSecond) TgmnG/Z  
{ ;CmS ~K:  
try{ Y2ZT.l  
Thread.sleep(nSecond); F`Q[6"<a  
} uW@oyZ

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catch(Exception e) zQ@I}K t  
{ m'6&9Jak  
e.printStackTrace (); {|&5_][  
} (Pf+0,2  
} aJ-K?xQ  
EN;}$jZ>47  
//日志 s:#V(<J  
public static void log(String sMsg) sk,ox~0R  
{ mpI5J'>]  
System.err.println(sMsg); q)S^P>  
} {mZC$U'  
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public static void log(int sMsg) ur$ 
_  
{ #fM#p+v  
System.err.println(sMsg); E:JJ3X|  
} %C~1^9uq  
} =vDEfO/T  
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86 W9rR  
/* 6:Ch^c+IZ  
**TestMethod.java XQ9O$ ~q  
*/ )}D'<^=#T  
package NetFox; wkA+j9.  
!}v=N";c  
p^%YBY#,H  
public class TestMethod {  FT#8L  
-Zf@VW,NI  
;aI[=?<x  
public TestMethod() 6*B19+-  
{ ///xx/weblogic60b2_win.exe M=FxB;v  
try{ m?pstuUK(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h{HF8>u[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7'Zky2F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M)'HCnvs'  
fileFetch.start(); )6,de2Pb  
} yj;sSRT  
catch(Exception e){e.printStackTrace ();} kzn5M&f>  
dv8>[#  
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} cC=[Saatsf  
3 Nreqq  
42
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public static void main(String[] args) SM0~fAtE  
{ tZ=E')!\  
new TestMethod(); C${Vg{g7a  
} @R/07&lBR  
} {sihus#Q  
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