http断点续传简单实现（java)

/* eev-";c  
**SiteFileFetch.java f}t8V% ^E  
*/ @GWJq 3e  
package NetFox; bs&>QsI?j  
import java.io.*; 8Drz i!}  
import java.net.*; gkmV;0  
1N}vz(0"  
)`BKEaf  
public class SiteFileFetch extends Thread { p/U{*i]t  
4:9N]1JCb  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1{AK=H')  
long[] nStartPos; //开始位置 jx{wOb~oO)  
long[] nEndPos; //结束位置 z
*UgRLKZD  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Y:R*AOx  
long nFileLength; //文件长度 ni85Ne$  
boolean bFirst = true; //是否第一次取文件 IG Ax+3V  
boolean bStop = false; //停止标志 4nrn Npf`b  
File tmpFile; //文件下载的临时信息 EO`e
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DataOutputStream output; //输出到文件的输出流 w,az{\  
aD+4uGN  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） a
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public SiteFileFetch(SiteInfoBean bean) throws IOException q5G`q&O5  
{ {e5DQ21.  
siteInfoBean = bean; v`@NwH<r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *M^<oG  
if(tmpFile.exists ()) yv|`A2@9  
{ ,M9e *  
bFirst = false; bq2f?uD-}
 
read_nPos(); FeZ
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} Za,myuI+  
else \ZA@r|=$  
{ L54]l^ls>  
nStartPos = new long[bean.getNSplitter()]; 61w ({F  
nEndPos = new long[bean.getNSplitter()]; b Rc,Y<  
} \U3v5|Q  
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} PIAE6,*  
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public void run() }xry
 
{ N
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//获得文件长度 H:)_;k  
//分割文件 @^Rl{p  
//实例FileSplitterFetch 15S&,$1&  
//启动FileSplitterFetch线程 y 2)W"PuG  
//等待子线程返回 6e8 gFQ"w2  
try{ .DI?-=p|_#  
if(bFirst) osl\j]U8  
{ 2qot(Zs1i  
nFileLength = getFileSize(); ,+5:}hR+  
if(nFileLength == -1) d'"|Qg_'  
{  wX5q=I  
System.err.println("File Length is not known!"); d N$,AOT  
} !S%0#d2  
else if(nFileLength == -2) 1F_$[iIX]  
{
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System.err.println("File is not access!"); _, E/HAX  
} Cs(sar:7  
else >(-A"jf  
{ *4e?y  
for(int i=0;i<nStartPos.length;i++) \1SC:gN*#  
{ i),bAU!+m  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 'J$@~P  
} 4l7 Ny\J  
for(int i=0;i<nEndPos.length-1;i++) ,kf.'N  
{ q^:VF()d_z  
nEndPos = nStartPos[i+1]; 51u\am'T  
} @dUN3,}  
nEndPos[nEndPos.length-1] = nFileLength; ?;_*8Doq-a  
} 1BEs> Sm  
} '$c9S[  
r6nnRN/S=  
:w-:B^VB  
//启动子线程 $}.+}'7$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1+gFfKq  
for(int i=0;i<nStartPos.length;i++) |;7mDhj=  
{ &=x4M]t9L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;*$e8y2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), n\M8>9c  
nStartPos,nEndPos,i); Y!8FW|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yIcTc  
fileSplitterFetch.start(); c6
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} [_n
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `KN>0R2k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); O5aXa_A_u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", MI'"Xzp{s  
nEndPos = " + nFileLength); 4=ovm[  
// fileSplitterFetch[nPos.length-1].start(); ,zdGY]$  
j!w{  
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//等待子线程结束 y|)VNnWM  
//int count = 0; .$H"j>  
//是否结束while循环 ,<* I5:  
boolean breakWhile = false; n0!2-Q5U)h  
f9 \$,7F  
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while(!bStop) */l;e<E  
{ aG83@ABx  
write_nPos();
pr,,E[  
Utility.sleep(500); )AxD|A  
breakWhile = true; ^Fh*9[Zf$  
FuBt`H  
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for(int i=0;i<nStartPos.length;i++) 9(J,&)J  
{ n|{#5#  
if(!fileSplitterFetch.bDownOver) E]rXp~AZm  
{ u5Vgi0}A  
breakWhile = false; TIxOMYy  
break; I`_I^C3  
}
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} 9OV@z6
  
if(breakWhile) YR*gOTD  
break; rD~/]y)t  
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//count++; }L)[>  
//if(count>4) &hO-6(^I  
// siteStop(); ;aV3j/  
} W~0rSVD$<z  
5h&sdzfG  
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System.err.println("文件下载结束！"); 9-/q-,  
} T{k_3[{0o  
catch(Exception e){e.printStackTrace ();} Gk{ 'U  
} !9WGZfK+0Y  
gK QJ^a\!  
;_vhKU)%J#  
//获得文件长度 9e=}PL  
public long getFileSize() -R]0cefC<f  
{ Bd <0}  
int nFileLength = -1; P*A+k"DU1  
try{ zXx/\B$&d*  
URL url = new URL(siteInfoBean.getSSiteURL()); fJ[ ^_,O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m~5 unB9  
httpConnection.setRequestProperty("User-Agent","NetFox"); s`_EkFw>Gl  
h/t;ZLUAZP  
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int responseCode=httpConnection.getResponseCode(); `z\hQ%1!F  
if(responseCode>=400) _i}b]xfM  
{ I09 W=  
processErrorCode(responseCode); O{_t*sO9q*  
return -2; //-2 represent access is error vt{[_L(h  
} 8Y.qP"
s  
v*?8:>:}  
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String sHeader; v?O
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for(int i=1;;i++) Ku l<Q<  
{ 3e&+[j  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Yi%lWbr  
//Utility.log(in.readLine()); (|K+1R  
sHeader=httpConnection.getHeaderFieldKey(i); x*7A33@i  
if(sHeader!=null) "-$}GUK?Z  
{ 1H-Y3G>jN  
if(sHeader.equals("Content-Length")) FC] *^B  
{ 7b[sW|{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); SG)Fk *1  
break; EL$DvJ~  
} <#h,_WP*  
} z3uR1vF'  
else S-S%IdL  
break; C P}fxDW  
} A7Ql%$v7^  
} ^x\VMd3*w  
catch(IOException e){e.printStackTrace ();} P+o"]/7U  
catch(Exception e){e.printStackTrace ();} G0UaE1n  
{P8d^=#q  
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Utility.log(nFileLength); /e0B$UymFu  
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return nFileLength; k9}8xpH  
} %=UD~5!G0  
iAk:CJ{  
9jTBLp-i#N  
//保存下载信息（文件指针位置） ->b5"{t  
private void write_nPos() v`Jt+?I  
{ wHj1+W  
try{ $&as5z8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ._G,uP$  
output.writeInt(nStartPos.length); %^@l5h.lqB  
for(int i=0;i<nStartPos.length;i++) ^YLC{V  
{ o99ExQ.  
// output.writeLong(nPos); <{kPa_`'  
output.writeLong(fileSplitterFetch.nStartPos); _u[tv,  
output.writeLong(fileSplitterFetch.nEndPos); 1?Y>Xz  
} <-v zS;  
output.close(); m[}k]PB>  
} Ic2?1<IZA  
catch(IOException e){e.printStackTrace ();} rE+B}O  
catch(Exception e){e.printStackTrace ();} S[zvR9AW&  
} GQtNk<?$I  
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m !*F5x  
//读取保存的下载信息（文件指针位置） BYq80Vk%@  
private void read_nPos() mKZzSd)p  
{ eTa_RO,x  
try{ @:}c(j  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); y|6n:<o  
int nCount = input.readInt(); .G[/4h :.  
nStartPos = new long[nCount]; G?$@6  
nEndPos = new long[nCount]; Ab@G^SLX  
for(int i=0;i<nStartPos.length;i++) :*}Q/]N  
{ =x8[%+  
nStartPos = input.readLong(); \ASt&'E  
nEndPos = input.readLong(); c*)T4n[e  
} % "(&a'B  
input.close();  g{Hgs  
} (Mk7"FC7  
catch(IOException e){e.printStackTrace ();} i1B!oZ3q  
catch(Exception e){e.printStackTrace ();} t1?aw<  
} j$)ogG
u  
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private void processErrorCode(int nErrorCode) u_k[<&$  
{ "W7|Xp  
System.err.println("Error Code : " + nErrorCode); `WayR^9  
} 4C*ywP  
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//停止文件下载 d6J/)nl  
public void siteStop() OD8 fn  
{ aFTWzz  
bStop = true; QF>T)1&J[7  
for(int i=0;i<nStartPos.length;i++) &*v\t\]  
fileSplitterFetch.splitterStop(); &en. m>9,  
Wl
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} M6g8+sio  
} o!tC{"g  
//负责部分文件的抓取 K?uZIDo  
**FileSplitterFetch.java +u$l]~St\  
*/ #LasTN9  
package NetFox; q/ljH_-  
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b}
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import java.io.*; pl]|yIZ  
import java.net.*; hP"2X"kz&  
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public class FileSplitterFetch extends Thread { lbHgxZ  
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String sURL; //File URL ?Lg(,-:  
long nStartPos; //File Snippet Start Position joe)b  
long nEndPos; //File Snippet End Position d/; tq  
int nThreadID; //Thread's ID "`% ,l|D  
boolean bDownOver = false; //Downing is over [M\ an6h6O  
boolean bStop = false; //Stop identical Jy(G A  
FileAccessI fileAccessI = null; //File Access interface GL n M1  
{+J{t\`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3]*Kz*i  
{ ? "I %K%  
this.sURL = sURL; tl0|.Q,  
this.nStartPos = nStart; ?AyxRbk  
this.nEndPos = nEnd; d>p' A_  
nThreadID = id; kOydh(yE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 r07u6OA  
} Xz^nm\  
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public void run() V%
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{ KsKE#])&l  
while(nStartPos < nEndPos && !bStop) eh9?GUr5  
{ Dj\nsc@e3  
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try{ #~ x7G  
URL url = new URL(sURL); gC1LQ!:;Oi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k6bct@7  
httpConnection.setRequestProperty("User-Agent","NetFox"); h3@tZL#g  
String sProperty = "bytes="+nStartPos+"-"; ~q ^o|?  
httpConnection.setRequestProperty("RANGE",sProperty); OFtaOjsyUa  
Utility.log(sProperty); b G:\*1T  
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;E.]:Ia~  
InputStream input = httpConnection.getInputStream();  vD#U+  
//logResponseHead(httpConnection); 'ZF6Z9  
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byte[] b = new byte[1024]; d0>U-.  
int nRead; ,j_js8r  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) lx|Aw@C3~  
{ R%jOgZG  
nStartPos += fileAccessI.write(b,0,nRead); z x-[@G  
//if(nThreadID == 1) j}uL  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >?@5>wF  
} u}%OC43  
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Utility.log("Thread " + nThreadID + " is over!"); n[jXqFm!`  
bDownOver = true; "u6pl);G  
//nPos = fileAccessI.write (b,0,nRead); rDWAZ<;;  
} ogFo/TKM  
catch(Exception e){e.printStackTrace ();} _pTcSp3  
} vqeH<$WHvy  
} *p(_="J,  
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c]M+|R5  
//打印回应的头信息 cpOt?XYR~  
public void logResponseHead(HttpURLConnection con) )k(K/m  
{ X~r9yl>  
for(int i=1;;i++) LACrg  
{ o ]*yI[\  
String header=con.getHeaderFieldKey(i); x {NBhq(4  
if(header!=null) GJ%^hr`P  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0Q{lyu  
Utility.log(header+" : "+con.getHeaderField(header)); }h^ fX  
else 1K9.3n   
break; eke[{%L  
} + +L7*1t  
} i6#*y!3{  
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public void splitterStop() !P{ /;Q  
{ |Y!^E %*  
bStop = true; )Eozo4~  
} +Csb8  
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} +v B}E  
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/*  :tZsSK  
**FileAccess.java dUv@u!}B  
*//文件访问(定位，写) wH|%3@eJ  
package NetFox; cP?GRMX@}  
import java.io.*; 8ae`V!5  
li%@HdA!  
pb97S^K[  
public class FileAccessI implements Serializable{ U;bx^2<m  
N*A*\B%{x'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Iy_5k8]  
RandomAccessFile oSavedFile; AZ!/{1Az  
long nPos; b:S$oE  
9?\cm}^?  
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public FileAccessI() throws IOException }n&nuaj  
{ "
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this("",0); +<\LY(o  
} 8[@,i|kgg0  
+'m9b7+v  
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public FileAccessI(String sName,long nPos) throws IOException ->I.D?p  
{ FsqH:I4O  
oSavedFile = new RandomAccessFile(sName,"rw"); 5X^\AW  
this.nPos = nPos; X4o#kW  
oSavedFile.seek(nPos); NV
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} (A?>U_@  
YW7w>}aW  
;>7~@ K  
public synchronized int write(byte[] b,int nStart,int nLen) HB )+.e  
{ "[ S[vkI  
int n = -1; x;W!sO@$  
try{ qXtC7uNj$  
oSavedFile.write(b,nStart,nLen); _`SDG5  
n = nLen; !mK()#6  
} Sd6O?&(  
catch(IOException e) 7Q!ksp  
{ [7><^?t V  
e.printStackTrace (); diXWm-ZKL  
} ,It0brF  
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 (
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return n; QI[WXxp  
} uT]$R  
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} q#j[0,^ $  
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/* q!W,2xqZoq  
**SiteInfoBean.java gbMA-r:IC  
*/ Vn_&q6Pa  
package NetFox; f8
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Ho(MO!(  
public class SiteInfoBean { \L
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private String sSiteURL; //Site's URL -|'@:cIZ  
private String sFilePath; //Saved File's Path -Jd

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private String sFileName; //Saved File's Name Z+V%~C1  
private int nSplitter; //Count of Splited Downloading File W)1nc"WqY  
H^Pq[3NQ  
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public SiteInfoBean() kVLZdXn,q2  
{//nSplitter的缺省值为5 | K|AUI  
//default value of nSplitter is 5 y3j$?oM  
this("","","",5); nOyG7:  
} JA{kifu0+  
t!wbT79/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;ZB=@@l(  
{ Vw;iE=L  
sSiteURL= sURL; < R"Y^]P=  
sFilePath = sPath; PoZ$3V$(Lz  
sFileName = sName; !9gpuS[  
this.nSplitter = nSpiltter; ^%*qe5J  
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} T.De1Q|  
\ MuKS4  
#HL$`&m  
public String getSSiteURL() 0qR#o/~I  
{ W+u@UJi  
return sSiteURL; +;!^aNJ,  
} eAO@B
  
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bh" Caz.(t  
public void setSSiteURL(String value) zk }SEt-  
{ 5[\g87\  
sSiteURL = value; bLl ?!G.  
} /E/6(c  

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public String getSFilePath() 0F uj-q  
{ dw#pObH|`  
return sFilePath; HziQ%QR  
} B_#M)d O  

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public void setSFilePath(String value) >mQD/U  
{ a%y*e+oM  
sFilePath = value; NjS<DzKhK  
} {<IHiB35q  
pV<K=;:x>  
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public String getSFileName() e]1)_;b*  
{ Dg^s$2  
return sFileName; + d>2'  
}  k=t{o  
wR 2`*.O  
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public void setSFileName(String value) Q_/UC#I8  
{ Oc~<
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sFileName = value; ,X| >d
 
} kFQo[O]  
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public int getNSplitter() aa]|  
{ U0|wC,7"  
return nSplitter; fZs}u<3Q)  
} !j6CvclT  
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n%2c<@p#  
public void setNSplitter(int nCount) *` -  
{ q%s<y+  
nSplitter = nCount; Yh,,(V6  
} aEUEy:.  
} heES [  
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% T$!I(L&  
/* fuf'r>1n  
**Utility.java Cs]\3R|D`  
*/ J{;\TNkJ  
package NetFox; "2!5g)iO  
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public class Utility { {Y+e|B0  
4\U"e*  
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public Utility() N+UBXhh
  
{ 4fL>Ou[YuX  
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} 6C_H0a/h&  
j%S} T)pX  
//线程睡眠 mg3YKHNG  
public static void sleep(int nSecond) ZV/g_i#  
{ MA=gCG/JD  
try{ H8Ra!FW@  
Thread.sleep(nSecond); IYr4  
} F6{Q1DqI  
catch(Exception e) 93)
1  
{ ~!fOl)F  
e.printStackTrace (); :y~l?0b&8  
} nqYarHi  
} <7%#RJwe  
(^|vN;  
//日志 0;5qo~1  
public static void log(String sMsg) utdus:B#0  
{ 0d,&)  
System.err.println(sMsg); |@D%y&  
} CrGDo9JdvT  
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+ VhD]!  
public static void log(int sMsg) N@? z&urQi  
{ R"`<ZY6(Ou  
System.err.println(sMsg); }1Hy[4B(k\  
} ~Ctq  
} I~M@v59C  
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/* *kGk.a=  
**TestMethod.java |r`0< `  
*/ FPAj}
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package NetFox; p?<T _9e  
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L# .vbf  
public class TestMethod { Ap(>mUs!i  
Qv;^nj{\qV  
- [vH4~  
public TestMethod() 2,6|l.WFpE  
{ ///xx/weblogic60b2_win.exe CVgVyy^  
try{ OYIH**?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); H3|x  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]#O~lq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); /kFw(l_.  
fileFetch.start(); T;Ra/H
 
} enQev?8%  
catch(Exception e){e.printStackTrace ();} ?Hf8<C}3  
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} uWrvkLGN  
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public static void main(String[] args) N9AM% H
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{ s+]6X*)  
new TestMethod(); X|pOw,"  
} 3Yf!H-(\uB  
} S4>1d-  
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