http断点续传简单实现（java)

/* "8yDqm  
**SiteFileFetch.java "CT`]:GGK  
*/ dC}4Er  
package NetFox; w>#.id[k  
import java.io.*; zU>bT20x/  
import java.net.*; 8x6{[Tx   
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public class SiteFileFetch extends Thread { <
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SiteInfoBean siteInfoBean = null; //文件信息Bean 5NYYrA8,^  
long[] nStartPos; //开始位置 cA B^]j  
long[] nEndPos; //结束位置 )RwO2H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 yi1V\8DC  
long nFileLength; //文件长度 Yh;A  
boolean bFirst = true; //是否第一次取文件 Zv1/J}+  
boolean bStop = false; //停止标志 Ds%~J  
File tmpFile; //文件下载的临时信息 m[*y9A1  
DataOutputStream output; //输出到文件的输出流 ![@\p5-e  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） d[Rs  
public SiteFileFetch(SiteInfoBean bean) throws IOException @$d_JwI  
{ r)t-_p37  
siteInfoBean = bean; ]a=Bc~g91  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0\^K\J,.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $P~Tt4068  
if(tmpFile.exists ()) sr,8Qd0M  
{ s av  
bFirst = false; ~Aq$GH4  
read_nPos(); >5=uq _QY  
} 8Ow0A  
else BnLE+
X  
{ naKB2y]l  
nStartPos = new long[bean.getNSplitter()]; ZvO,1B  
nEndPos = new long[bean.getNSplitter()]; L%O( I  
} ~w9ZSSb4  
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} #>\+6W17U  
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public void run() CK+_T}+-  
{ Enj],I  
//获得文件长度 WH^rM`9  
//分割文件 {$mj9?n=v  
//实例FileSplitterFetch Mw+8p}E  
//启动FileSplitterFetch线程 v'zf*]9  
//等待子线程返回 C|A:^6d3=  
try{ Pa!r*(M)C  
if(bFirst) B}y-zj;T  
{ ;MR(Ea
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nFileLength = getFileSize(); ;ywQk| r  
if(nFileLength == -1) GM<r{6Qy  
{ c);(+b  
System.err.println("File Length is not known!"); 7Q9zEd"d  
} C}{$'#DV2  
else if(nFileLength == -2) a_0G4@=T  
{ i`1QR@11  
System.err.println("File is not access!"); T;%ceLD  
} e/<Og\}P/
 
else tCdgtZm  
{ LAwl9YnG:  
for(int i=0;i<nStartPos.length;i++) b}[W[J}`  
{ 85fBKpEe  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); kE
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} G*|2qX"o  
for(int i=0;i<nEndPos.length-1;i++) huau(s0um  
{ v*nX  
nEndPos = nStartPos[i+1]; y8KJoVPiM  
} ega
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nEndPos[nEndPos.length-1] = nFileLength; &r;4$7  
} m"!!)
 
} ;Vad| -  
TY=BP!s  
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//启动子线程 av1*i3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =B(zW.Gf  
for(int i=0;i<nStartPos.length;i++) ^L;`F  
{ bqMoO7&c  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8yH) 8:w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )h~MIpWR  
nStartPos,nEndPos,i); pt;kN&A^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !5
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fileSplitterFetch.start(); V$wf;v0d(  
} /R< Q~G|\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AG#5_0]P~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .(  vS/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {O
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nEndPos = " + nFileLength); "~4ULl<i'  
// fileSplitterFetch[nPos.length-1].start(); ztG_::QtG]  
,2)LH'Xx  
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//等待子线程结束 !V.'~xj  
//int count = 0; EeKEw Sg  
//是否结束while循环 YSt']  
boolean breakWhile = false; -O_5OT4  
">kfX1LT  
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while(!bStop)  _tN"<9v.  
{ xv9Z~JwH  
write_nPos(); a Kb2:1EQ  
Utility.sleep(500); =%|S$J  
breakWhile = true; Gu&?Gn oc  
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for(int i=0;i<nStartPos.length;i++) @3{'!#/  
{ |-I[{"6q$@  
if(!fileSplitterFetch.bDownOver) 1P4jdp=~  
{ 4)iSz>  
breakWhile = false; _ 9Tv*@  
break; $CO^dFf  
} :a3Pnq$]E  
}
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if(breakWhile) G7`7e@
{  
break; [,-MC7>]  
`w]=xe  
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//count++; \Btv76*,  
//if(count>4) ,'F;s:WM,  
// siteStop(); 'rU [V
+  
} CO1D.5  
@Wy>4B^  
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System.err.println("文件下载结束！"); vj^vzFbK  
} ;&P%A<[`  
catch(Exception e){e.printStackTrace ();} JMw1qPJQ  
} r<Ll>R  
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wCvtw[6  
//获得文件长度 y_38;8ex  
public long getFileSize() "W|Sh#JF  
{ 3IZ^!J  
int nFileLength = -1; 7Rk eV  
try{ $TL~SVHj;{  
URL url = new URL(siteInfoBean.getSSiteURL()); DTt/nmKAqJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #~q{6()e:  
httpConnection.setRequestProperty("User-Agent","NetFox"); mKPyM<Q  
t*82^KDU  
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int responseCode=httpConnection.getResponseCode(); .ev'd&l.  
if(responseCode>=400) ^$24231^  
{ ' V;cA$ $  
processErrorCode(responseCode); H6x~mZu_:T  
return -2; //-2 represent access is error @X"p"3V  
} a84^"GH7  
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%.BbPR7?h  
String sHeader; 6YQ&+4  
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for(int i=1;;i++) vdYd~>w  
{ f:GZb?Wyd  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "Git@%80  
//Utility.log(in.readLine()); KO<Yc`Fs  
sHeader=httpConnection.getHeaderFieldKey(i); ~&[Wqn@MZ  
if(sHeader!=null) $U<so{xn%  
{ R)"Ds}1G  
if(sHeader.equals("Content-Length")) .dt7b4.kd  
{ Igt:M[ /  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ".O+";wk  
break; x1W<r)A )r  
} y5 $h  
} ZMy0iQ@  
else d_BECx<\  
break; YgNt>4K  
} ^]3Y11sI  
} sWP5=t(i+9  
catch(IOException e){e.printStackTrace ();} Yj|Oy  
catch(Exception e){e.printStackTrace ();} ,`v)nwP  
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]  
Utility.log(nFileLength);  #:_qo  
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return nFileLength; vcy}ZqWBO  
} NDEltG(  
.$y}}/{j?[  
d&4]?8}=.  
//保存下载信息（文件指针位置） w7cciD|  
private void write_nPos() +VkhM;'"C  
{ ?D]4*qsIlu  
try{ tI0d
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output = new DataOutputStream(new FileOutputStream(tmpFile)); 1T a48  
output.writeInt(nStartPos.length); `9n%Dy<  
for(int i=0;i<nStartPos.length;i++) Q3vC^}Dmr  
{ 4d#w}  
// output.writeLong(nPos); NJ^`vWi  
output.writeLong(fileSplitterFetch.nStartPos); z 0]K:YV_  
output.writeLong(fileSplitterFetch.nEndPos); 6e3s |  
} >KmOTM<{  
output.close(); 97lM*7h;  
} 8Eyi`~cAiH  
catch(IOException e){e.printStackTrace ();} 1O>wXq7q  
catch(Exception e){e.printStackTrace ();} Xp@8vu  
} v=
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//读取保存的下载信息（文件指针位置） ^I=c]D]);  
private void read_nPos() !qsk;Vk7Z  
{ s!esk%h{K  
try{ !'o5X]s  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 19Xc0ez  
int nCount = input.readInt(); m=<Tylv  
nStartPos = new long[nCount]; u[q1]]  
nEndPos = new long[nCount]; -B-?z?+(O  
for(int i=0;i<nStartPos.length;i++) YjN2 ,Xi  
{ ! /;@kXN
 
nStartPos = input.readLong(); =p,+a/*  
nEndPos = input.readLong(); WL$nchS9  
} v!n\A}^:  
input.close(); d0$dQg  
} wegu1Ny  
catch(IOException e){e.printStackTrace ();} ~N2){0j4  
catch(Exception e){e.printStackTrace ();} SN+B8*!  
} qP{S!Z(  
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private void processErrorCode(int nErrorCode) ,e{(r0  
{ 83~ Gu[  
System.err.println("Error Code : " + nErrorCode); DG,CL8bv  
} V#["Z}  
\]ouQR.t@\  
z/6/   
//停止文件下载 Dnn$-W|NC  
public void siteStop() gKy@$at&  
{ VU3xP2c:  
bStop = true; v-M3/*  
for(int i=0;i<nStartPos.length;i++) bfy `UZr  
fileSplitterFetch.splitterStop(); 6X2>zUHR  
>=Hm2daN  
6REv(E]  
} W`_pjld  
} qD=o;:~Km  
//负责部分文件的抓取 NfvvwG;M  
**FileSplitterFetch.java g"vg {Q  
*/ )';Rb$<Qn  
package NetFox; 5$Lo]H*  
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import java.io.*; g /D@/AU1u  
import java.net.*; r \+&{EEG  
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public class FileSplitterFetch extends Thread { ]v
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q}gj.@Q"  
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String sURL; //File URL 4Kjrk7GAx  
long nStartPos; //File Snippet Start Position vFz%#zk>  
long nEndPos; //File Snippet End Position 9s\(yC8h  
int nThreadID; //Thread's ID V\Oe]w  
boolean bDownOver = false; //Downing is over ^%l~

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boolean bStop = false; //Stop identical +]Ca_`  
FileAccessI fileAccessI = null; //File Access interface Y2709LWmP  
7|4hs:4mD  
i(R&Q;{E^  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q] g'rO'  
{ vJ5`:4n"  
this.sURL = sURL; +p6cG\Gp  
this.nStartPos = nStart; (qd$wv^h  
this.nEndPos = nEnd; [=M0%"  
nThreadID = id; F[PIo7?K  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [<SM*fQ>t  
} 6v~` jS%3  
y,&.<
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public void run() ]"bkB+I  
{ jO xH'1I  
while(nStartPos < nEndPos && !bStop) n5CjwLgu\b  
{ MG ,exN @  
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bB^% O^:  
try{ 3 $7TeqfAC  
URL url = new URL(sURL); &"GHD{ix  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @y:mj \J9  
httpConnection.setRequestProperty("User-Agent","NetFox"); %-ih$ZY  
String sProperty = "bytes="+nStartPos+"-"; l%"[857  
httpConnection.setRequestProperty("RANGE",sProperty); k^3 ?Z2a  
Utility.log(sProperty); Z#7T!/28  
*:t]|$;E\  
i!8 o(!I  
InputStream input = httpConnection.getInputStream(); o('W2Bs-o  
//logResponseHead(httpConnection); <hlH@[7!  
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ghvF%-."1  
byte[] b = new byte[1024]; }p-<+sFo  
int nRead; mXZOkx{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @Dc?fyY*o<  
{
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nStartPos += fileAccessI.write(b,0,nRead); jP'.a. ^o$  
//if(nThreadID == 1) wI'8B{[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yNp l0 d  
} 3/a$oO
 
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Utility.log("Thread " + nThreadID + " is over!"); Mf0!-bu  
bDownOver = true; e='bc7$  
//nPos = fileAccessI.write (b,0,nRead); lK;/97Ze  
} (?MRbX]@  
catch(Exception e){e.printStackTrace ();} &1O[N*$e  
} A
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} GE4d=;
5  
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}'HJVB_  
//打印回应的头信息 :%GxU;<E{  
public void logResponseHead(HttpURLConnection con) 0{|ib !  
{ <3\t J  
for(int i=1;;i++) @ yJ/!9?^  
{ RFF&-M]  
String header=con.getHeaderFieldKey(i); &W/C2cpmR  
if(header!=null) =XWew*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4u5^I;4pL  
Utility.log(header+" : "+con.getHeaderField(header)); :ie7HF  
else TTjj.fq6  
break; *O') {(  
} Xh==F:  
} u@d`$]/>F  
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public void splitterStop() X\3IY:Q@T  
{  _Y@'<S.  
bStop = true; PAF2=  
} 1_vaSEov  
p"^^9'`=  
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} e6s-;
 
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/* }>:v  
**FileAccess.java _2{i}L  
*//文件访问(定位，写) 2!QS&i  
package NetFox; ?_9cFo59:  
import java.io.*; | >xUgpQi  
[~$Ji&Dd  
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public class FileAccessI implements Serializable{ CL/8p;
  
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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 F?2(U\k#  
RandomAccessFile oSavedFile; vPuPSE%M  
long nPos; xM85^B'  
= !D<1<  
 8.D$J  
public FileAccessI() throws IOException \~ O6S`,  
{ 2d+IROA  
this("",0);
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} r.M8#YL  
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public FileAccessI(String sName,long nPos) throws IOException RW 23lRA6  
{ jYKs| J)[  
oSavedFile = new RandomAccessFile(sName,"rw"); LLOe  
this.nPos = nPos; !?B9 0(  
oSavedFile.seek(nPos); Qz&I~7aoyV  
} A S;ra,x  
q[]EVs0$ew  
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public synchronized int write(byte[] b,int nStart,int nLen) jM1|+o*Wr  
{ \XwXs5"G  
int n = -1; @=x=dL
(  
try{ s$xctIbm?,  
oSavedFile.write(b,nStart,nLen); *%5#\ I  
n = nLen; 2#'{
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} ehj&A+Ip  
catch(IOException e) "PGEiLY  
{ ==I:>+_^|  
e.printStackTrace (); _5#f9,m1  
} ]t_AXKd  
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return n; {>>ozB.  
} p"ht|x  
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} ^.j
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/* k<ds7k1m  
**SiteInfoBean.java R^P~iAO  
*/ [0N==Ym1  
package NetFox; 4lC:svF  
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public class SiteInfoBean { Q)yhpwrX  
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private String sSiteURL; //Site's URL uy{mSx?td  
private String sFilePath; //Saved File's Path +#O?a`f  
private String sFileName; //Saved File's Name %YefTk8cr,  
private int nSplitter; //Count of Splited Downloading File x:=Kr@VP  
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public SiteInfoBean() PH97O`"  
{//nSplitter的缺省值为5 2H fP$.  
//default value of nSplitter is 5 ga^O
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this("","","",5); rP,i,1Ar 4  
} /Q5pAn-u  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \tLJ( <8  
{ @5Q}o3.zA-  
sSiteURL= sURL; 2qKo|'gL`  
sFilePath = sPath; sl-LX)*N#  
sFileName = sName; T=:&W3  
this.nSplitter = nSpiltter; g"]%5Ow1  
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Q?n} ~(%&  
} -cNh5~p=  
b")&"o)G2W  
vp &jSfQ^  
public String getSSiteURL() |332G6
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{ ~|@aV:k  
return sSiteURL; wcP0PfY  
} ~ C6<75  
9+h9]
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public void setSSiteURL(String value) j2deb`GD  
{ 6'395x_.\  
sSiteURL = value; K+Al8L?K_  
} "Q
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public String getSFilePath() DzO0V"+H}k  
{ bmhvC9  
return sFilePath; D|9C|
q  
} ,%mTKOs  
RfDIwkpp  
=|S8.|r+  
public void setSFilePath(String value) xZPSoxu  
{ @no]*?Gpa  
sFilePath = value; %m!o#y(hD`  
} h1G]w/.ws  
Y}'C'PR  
i;*c|ma1>  
public String getSFileName() 9c8zH{T_{  
{ *fW&-ic  
return sFileName; IyIh0B~i  
} %~J90a  
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~el#pf~  
public void setSFileName(String value) wKe^5|Rr  
{ j[m\;3Sp  
sFileName = value; !tv3.:eT  
} <<LmO-92  
n_AW0i.  
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public int getNSplitter() r^_8y8&l  
{ HD?z  
return nSplitter; AvRZf-Geg  
} Crh5^?  
~ygiKsD6b  
[=u8$5/a  
public void setNSplitter(int nCount) vLDMa>  
{ ~YO')  
nSplitter = nCount; >k*QkIyq  
} u!oHP  
} a+)Yk8%KY  
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/* RPPxiYU^  
**Utility.java I/jMe'Kp  
*/ WW0N"m'  
package NetFox; 71 hv~Nk/x  
$@Zb]gavt?  
|;6FhDW+'  
public class Utility { ?0hk~8c  
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7on$}=%  
public Utility() 9~ajEs  
{ *'`ByS  
,~X^8oY  
f|WNPFQ$x  
} 'SYjEhvw  
)"|'=  
//线程睡眠 (k6=o';y  
public static void sleep(int nSecond) /],:sS7  
{ P9:7_Vc  
try{ !w]!\H  
Thread.sleep(nSecond); y1cAw   
} 6=Kl[U0Y  
catch(Exception e) f?#:@ zcL  
{ s#&jE GBug  
e.printStackTrace (); :RzcK>Gub=  
} Y~dRvt0_w  
} QB#f'X  
}h5pM`|1  
//日志 YNn,{Xi  
public static void log(String sMsg) ymY,*Rb  
{ hZY+dHa]  
System.err.println(sMsg); kWjCSC>jA  
} J
[2;&-@  
zv <,  
Of7j~kdh83  
public static void log(int sMsg) 7n,nODbJ  
{ 3F5r3T6j}  
System.err.println(sMsg); vUS$DUF  
} uZz^>*b  
} Z$X2*k6PK  
37?%xQ!  
bd_U%0)pi1  
/* :(} {uG  
**TestMethod.java }di)4=U9  
*/ QKCc5  
package NetFox; jeN_ sm81b  
?CAP8_  
Jh{(xGA  
public class TestMethod { 0gm+R3;k^  
1& YcCN\k  
l@q.4hT  
public TestMethod() <'v?WV_  
{ ///xx/weblogic60b2_win.exe Cj"k Fq4  
try{ @NlnZfMu  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); SY`NZJK  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Os*,@N3t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); U;i:k%Bzy  
fileFetch.start(); cm%QV?  
} }KCXo/y  
catch(Exception e){e.printStackTrace ();} wHWd~K_q  
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} .oO_x>  
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public static void main(String[] args) R/~j <.s3P  
{ i:&Y{iPQp  
new TestMethod(); `dMOBYV  
} UN`-;!  
} J*.Nf)i  
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