http断点续传简单实现（java)

/* 6)qp*P$L  
**SiteFileFetch.java dRW$T5dac  
*/ _ \D"E>oM  
package NetFox; A
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import java.io.*; X|}2_B  
import java.net.*; 3BdX  
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public class SiteFileFetch extends Thread { tF7hFL5f  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :g6n,p_#  
long[] nStartPos; //开始位置 Vi*e@IP/  
long[] nEndPos; //结束位置 i
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FileSplitterFetch[] fileSplitterFetch; //子线程对象
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long nFileLength; //文件长度 3B0PGvCI1  
boolean bFirst = true; //是否第一次取文件 CrC=A=e  
boolean bStop = false; //停止标志 v+G=E2Lh
v  
File tmpFile; //文件下载的临时信息 QA3/
 
DataOutputStream output; //输出到文件的输出流 r)^
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -0Cnp/Yj@  
public SiteFileFetch(SiteInfoBean bean) throws IOException :|+Qe e  
{ 1yQejw  
siteInfoBean = bean; G2Vv i[c  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eJ0?=u!x  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^uBxgWIC  
if(tmpFile.exists ()) mN|r)4{`  
{ b2,!g }I  
bFirst = false; .,0bE  
read_nPos(); +Q$h ]^>~  
} k{;,6H  
else -fS.9+k0/  
{ bi[IqU!9  
nStartPos = new long[bean.getNSplitter()]; \xv;sl$f  
nEndPos = new long[bean.getNSplitter()]; <-'$~G j  
} U8.7>ENnP&  
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} ~6YMD  
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public void run() ^XbU~3(  
{ JjaoOe  
//获得文件长度 vM:cWat  
//分割文件 Hso|e?Z  
//实例FileSplitterFetch 4}+/F}TbJ5  
//启动FileSplitterFetch线程 g0R~&AN!g  
//等待子线程返回 h/?l4iR*  
try{ wE+${B03  
if(bFirst) fU=B4V4@  
{ >B]'fUt5a  
nFileLength = getFileSize(); .X# `k  
if(nFileLength == -1) hGpv2>M  
{ %_!bRo  
System.err.println("File Length is not known!"); MxT-1&XL  
} 7}M2bH} \K  
else if(nFileLength == -2) ,eTU/Q>{,&  
{ ;)N>t\v  
System.err.println("File is not access!"); :VTTh |E%#  
} eek7=Z  
else 'yMF~r3J  
{ d3=KTTi\  
for(int i=0;i<nStartPos.length;i++) <HbcNE~  
{ CrwwU7qKL  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?@E!u|]K  
} g$b<1:8  
for(int i=0;i<nEndPos.length-1;i++) j~!X;PV3  
{ z^T`x_mF  
nEndPos = nStartPos[i+1]; H1} RWaJ  
} @Y1s$,=xB  
nEndPos[nEndPos.length-1] = nFileLength; z11O F  
} h*-Pr8  
} 8ji_#og  
{{QELfH2  
Z]B~{!W1  
//启动子线程 6oGYnu;UZ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gHo?[pS%y  
for(int i=0;i<nStartPos.length;i++) Za1QC;7  
{ k |eBJ%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DQr Y*nH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =>_\fNy  
nStartPos,nEndPos,i); oz,e/v8~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }hhGu\  
fileSplitterFetch.start(); g"}%2~Urf  
} E"5*Ei)^3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <i&_ooX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @0/+_2MH-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sG F aL  
nEndPos = " + nFileLength); s+<Yg
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// fileSplitterFetch[nPos.length-1].start(); NA~V
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*2
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d'NIV9P`j]  
//等待子线程结束 m)'=G%y  
//int count = 0; 0"f\@8r(  
//是否结束while循环 
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boolean breakWhile = false; ,,q10iF  
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while(!bStop) %5"9</a&G  
{ }E50>g  
write_nPos(); |xdsl,  
Utility.sleep(500); X:nN0p #  
breakWhile = true; RwpdRBb  
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for(int i=0;i<nStartPos.length;i++) jK& h~)  
{ 0tT(W^ho g  
if(!fileSplitterFetch.bDownOver) JR@`2YP-  
{ l~w2B>i)  
breakWhile = false; *Doa*wQ  
break; YUtC.TR1  
} C26>BU<  
} H4&lb}  
if(breakWhile) Ku5\]  
break; TJ6*t!'*X  
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//count++; `ZyI!"  
//if(count>4) \fz<.l]  
// siteStop(); 4%>$-($  
} 7q?, ?  
#S!)JM|4wk  
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System.err.println("文件下载结束！"); Jh,]r?Bd  
} r*2+xDoEi  
catch(Exception e){e.printStackTrace ();} CQF:Rnb  
} G\2CR*  
lb4Pcdj  
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//获得文件长度 fI?>+I5  
public long getFileSize() ayR-\mZ  
{ y" RF;KW>  
int nFileLength = -1; !Xf5e*1IS  
try{ a*lh)l<KV  
URL url = new URL(siteInfoBean.getSSiteURL()); 46_xyz3+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); le|~BG hL  
httpConnection.setRequestProperty("User-Agent","NetFox"); JjtNP)We  
]!?;@$wx  
9-&Ttbb4)0  
int responseCode=httpConnection.getResponseCode(); ^a0um/+M}  
if(responseCode>=400) N7b8m?!  
{ ^ Edfv5  
processErrorCode(responseCode); t<.)Z-Ii  
return -2; //-2 represent access is error 36}?dRw#p  
} cOmw?kA*G  
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String sHeader; ,1~"eGl!  
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for(int i=1;;i++) 6a(yp3  
{ w1Nm&}V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); SE@LYeC}dE  
//Utility.log(in.readLine()); !`Fx
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sHeader=httpConnection.getHeaderFieldKey(i); [%"|G9  
if(sHeader!=null) >,V9H$n  
{ \:%(q/v"X  
if(sHeader.equals("Content-Length")) zqimR#u  
{ 1-8mFIK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); BRw .]&/  
break; gh/EU/~d  
} .0zY}`  
} pNG:0  
else e>} s;H,  
break; NW~N}5T  
} Q- cFtu-w  
} v [wb~uw\  
catch(IOException e){e.printStackTrace ();} 7x"
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catch(Exception e){e.printStackTrace ();} m~iXl,r  
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Utility.log(nFileLength); 0at/c-K`  
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return nFileLength; L O}@dL  
} `!obGMTQ<  
b)6D_Az7c  
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//保存下载信息（文件指针位置） W>${zVu  
private void write_nPos() 52@C9Q,  
{ H`*LBqDk  
try{ :tz#v`3o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +5w))9@  
output.writeInt(nStartPos.length); G!Op~p@Jm  
for(int i=0;i<nStartPos.length;i++) :vmH]{R  
{ !S$:*5=&  
// output.writeLong(nPos); GA$V0YQX  
output.writeLong(fileSplitterFetch.nStartPos); d2*fLEsF  
output.writeLong(fileSplitterFetch.nEndPos); hCi60%g/n  
} %:M^4~dc  
output.close(); ,1y@Z 5wy  
} / kF)  
catch(IOException e){e.printStackTrace ();} 6/
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catch(Exception e){e.printStackTrace ();} b:U$x20n$  
} [8Y:65  
{0L1X6eg  
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//读取保存的下载信息（文件指针位置） 9e<.lb^tP  
private void read_nPos() hwPw]Ln/  
{ >"??!|XG^  
try{ C/q'=:H;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DHyq^pJ  
int nCount = input.readInt(); qSM|hHDo)  
nStartPos = new long[nCount]; cutuDZ  
nEndPos = new long[nCount]; {AhthR%(1  
for(int i=0;i<nStartPos.length;i++) U'k*_g
 
{ 6]&OrS[  
nStartPos = input.readLong(); .6ylZ  
nEndPos = input.readLong(); TtJH7  
} 9)h"-H;5:  
input.close(); )cX*I gO  
} A
b~3{Q]#  
catch(IOException e){e.printStackTrace ();} qFicBpB  
catch(Exception e){e.printStackTrace ();} G'nmllB`]  
} j%Y#(Q>  
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private void processErrorCode(int nErrorCode) |.(dq^  
{ ]Oe2JfJwx  
System.err.println("Error Code : " + nErrorCode); r7RIRg_  
} R8Wr^s>'  
0%32=k7O[  
/,BD#|  
//停止文件下载 zUt'QH7E.  
public void siteStop() EB0TTJR?#  
{ ]RZ|u*l=x  
bStop = true; _F4Ii-6  
for(int i=0;i<nStartPos.length;i++) Wjo[ENHM  
fileSplitterFetch.splitterStop(); vt/x ,Y  
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](Xb_xMf  
} %@<8<6&q  
} fnpYT:%fG  
//负责部分文件的抓取 Y@NNrGDkT*  
**FileSplitterFetch.java \e:7)R2<!x  
*/ wVvF^VHV^  
package NetFox; 9)D6Nm  
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import java.io.*; N,<uf@LQ  
import java.net.*; <]6SN  
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public class FileSplitterFetch extends Thread { 3RigzT3  
59 h]UX=  
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String sURL; //File URL nB_?ckj,  
long nStartPos; //File Snippet Start Position C>]0YO k2  
long nEndPos; //File Snippet End Position xI{)6t$`  
int nThreadID; //Thread's ID *zaQx+L  
boolean bDownOver = false; //Downing is over p99]  
boolean bStop = false; //Stop identical $CRm3#+ ~  
FileAccessI fileAccessI = null; //File Access interface <KJ/<0l  
;/bewivNJ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vRznw&^E
 
{ S:u:z=:r  
this.sURL = sURL; }V'}E\\  
this.nStartPos = nStart; 2pZXZ  
this.nEndPos = nEnd; |sa]F5  
nThreadID = id; kAKK bmE
 
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d.[8c=$  
} #?RU;1)Cw  
2\R'@L*  
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public void run() ;p.v]0]is  
{ bc*X/).  
while(nStartPos < nEndPos && !bStop) <NHH
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{ R$EW4]j  
XP`Nf)3{Yd  
9,c(ys
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try{
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URL url = new URL(sURL); ~Q*%DRd&Z-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >|J`s~?  
httpConnection.setRequestProperty("User-Agent","NetFox"); \0A3]l  
String sProperty = "bytes="+nStartPos+"-"; y>S.?H:P  
httpConnection.setRequestProperty("RANGE",sProperty); ?#Ge.D~u  
Utility.log(sProperty); x" 7H5<  
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;Y)w@bNt@  
InputStream input = httpConnection.getInputStream(); bAdn &  
//logResponseHead(httpConnection); ov|d^)'  
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byte[] b = new byte[1024]; LmRy1T,act  
int nRead; Dxtp2wu%t  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) S};#+ufgTt  
{ .[YuRLGz  
nStartPos += fileAccessI.write(b,0,nRead); JX<)EZ!F  
//if(nThreadID == 1) <g-9T-Ky  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .Q<>-3\K  
} "x%Htq@  
nz%DM<0$  
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Utility.log("Thread " + nThreadID + " is over!"); m.hkbet/R  
bDownOver = true; -6Z\qxKqZ  
//nPos = fileAccessI.write (b,0,nRead); $5>e  
} },uF4M.K  
catch(Exception e){e.printStackTrace ();} +20G>y=+  
} RXNn[A4xfY  
} fAF1"4f  
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GeI-\F7b  
//打印回应的头信息 Cwr~HY  
public void logResponseHead(HttpURLConnection con) ^0Zf,40  
{ N1}c9}  
for(int i=1;;i++) MlcR"gl*  
{ {vs uPY  
String header=con.getHeaderFieldKey(i); |U~<3.:m:  
if(header!=null) lVd^ ^T*fh  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 84$nT>c  
Utility.log(header+" : "+con.getHeaderField(header)); ?xA:@:l/  
else XFg9P}"  
break; m)8BgCy  
} v0ujdp,B  
}  vx\r!]  
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public void splitterStop() v/@^Q1G/:  
{ y>:N{|  
bStop = true; 1}S S+>`  
} rUwZMli  
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} EJj.1/]|r  
5
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/* ,aOl_o -&  
**FileAccess.java _> f`!PlB|  
*//文件访问(定位，写) a Ve'ry  
package NetFox; N1Ng^aY0  
import java.io.*; ?U%QG5/>  
v>:Ur}u!D  
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public class FileAccessI implements Serializable{ *lYVY)L  
-^K"ZP1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Amp#GR1CA  
RandomAccessFile oSavedFile; y?rPlA_  
long nPos; \j+1V1t9  
iMAfJ-oN  
)5rb&M}  
public FileAccessI() throws IOException -O1>|y2rU  
{ au N6prGe  
this("",0); ,bXe<L)  
} }bs+-K  
YA''2Ii  
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public FileAccessI(String sName,long nPos) throws IOException Gp1?iX?ml  
{ 63^O|y\W8  
oSavedFile = new RandomAccessFile(sName,"rw"); cIUHa  
this.nPos = nPos; ?TM,Q  
oSavedFile.seek(nPos); +"x,x  
} Z.c'Hs+;  
nR7d4)  
d<% z 1Dj2  
public synchronized int write(byte[] b,int nStart,int nLen) B%
" d~5Y  
{ $}RJ,%~'x  
int n = -1; bG7O  
try{ cq5jPZ}  
oSavedFile.write(b,nStart,nLen); 1G"z<v B  
n = nLen; ;}7Rjl#  
} E08klC0
 
catch(IOException e) >x/z7v?^I  
{ Bs13^^hu
 
e.printStackTrace (); C`K?7v3$m  
} nv GF2(;l  
]}*R|1  
;t'5},(FP  
return n; 3?[dE<  
} pN!}UqfI-  
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} _|iSF2f,X  
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/* RdWRWxTn8+  
**SiteInfoBean.java d^Inb!%w  
*/ u_hD}V^x4  
package NetFox; b+,';bW  
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5
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public class SiteInfoBean { x%}^hiO<q  
,">]`|?  
7_%"BVb"  
private String sSiteURL; //Site's URL {`J)j6;  
private String sFilePath; //Saved File's Path 
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private String sFileName; //Saved File's Name `lQ3C{}  
private int nSplitter; //Count of Splited Downloading File $Oq^jUJ  
5)FJ:1-  
i;]"n;>+/  
public SiteInfoBean() {,3>"  
{//nSplitter的缺省值为5 XnDUa3  
//default value of nSplitter is 5 K:!"+q  
this("","","",5); V\{clJ\U  
} 
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q_TRq:&.  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?: N@!jeJ  
{ Hx#;Z  
sSiteURL= sURL; ?!;7:VIE  
sFilePath = sPath; AB=daie  
sFileName = sName; ;LcVr13J/  
this.nSplitter = nSpiltter; 9}l33T4T  
_  <WJ7  
Lilr0|U+  
} l%[EXZ  
?6yjy<D)$e  
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public String getSSiteURL() @GkILFN  
{ ? K;dp  
return sSiteURL; sA/pVU  
} %oq{L]C(rf  
+Fuqchjq  
M%Ji0v38  
public void setSSiteURL(String value) JM=JH 51`  
{ GYJ80k|  
sSiteURL = value; MJOz.=CbhR  
} ;hYS6  
6;u$&&c(  
3 N.~mR  
public String getSFilePath()
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{ /h+8A',  
return sFilePath; s1=X>'q  
} :QpuO1Gu  
^?U!pq-`  
q ]M+/sl  
public void setSFilePath(String value) i'4B3  
{ w,w{/T+B  
sFilePath = value; j:5=s%S  
} }3o|EXx=  
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public String getSFileName() 8JM&(Q%#  
{ 8C[C{qOJ  
return sFileName; nTuJEFn{  
} IAYR+c  
2HpHxVJ  
vk+VP 1D  
public void setSFileName(String value) |rJ=Ksc
 
{ t0o`-d(  
sFileName = value; =o Xsb  
} ZNf6;%oGG  
#z&&M"*a|  
X*M#F
T-  
public int getNSplitter() |kw)KEi}H  
{ UF?H>Y&  
return nSplitter; U@gn;@\  
} d\p,2  
;gBRCZ
 
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public void setNSplitter(int nCount) N03HQ
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{ 2r!s*b\Ix  
nSplitter = nCount; Zw
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} )^m%i]L_  
} aa?w:3  
,$+lFv3LE  
c\iA89msp  
/* =; ^%(%Y{m  
**Utility.java gXYI\.  
*/ V=zi >o`   
package NetFox; %1H[Wh(U  
33#0J$j7  
&{>cZh}\  
public class Utility { ~p1j`r;  
^.#jF#u~  
|UK}  
public Utility() 7N-
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{ S/^"@?z,vE  
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} "]z-: \ V  
<%maDM^_\(  
//线程睡眠 1abtgDL  
public static void sleep(int nSecond) f
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{ ~MS\  
try{ FO!]P  
Thread.sleep(nSecond); U'R)x";=  
} Yj)#k)x  
catch(Exception e) 6b+b/>G0  
{ q8s0AN'@t'  
e.printStackTrace (); OJ/
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} Ko;{I?c  
} 0}$Hi  
CACTE  
//日志 Cg&e(  
public static void log(String sMsg) hvA^n@nr  
{ lz"OC<D}(  
System.err.println(sMsg); BlXB7q,  
} }RmU%IYc  
kD*2~Z?;  
Ys@}3\Mc  
public static void log(int sMsg) an|x$e7|?  
{ `|,`QqDQ  
System.err.println(sMsg); }*lUah,@  
} +w.JpbQ&  
} >c9a0A  
nx8a$vI-TY  
PIH*Rw*GKZ  
/* Z0o~+Ct$  
**TestMethod.java $4tWI O  
*/ !|O~$2O@  
package NetFox; R$[#+X!  
i|T)p_y(!a  
r.#t63Rb  
public class TestMethod { }"=AG  
"NgxkbDEbG  
r9 ui|>U"  
public TestMethod() 3E>frR\!I  
{ ///xx/weblogic60b2_win.exe !R1.7}O  
try{ h&Efg  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); } w 5l  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?RK]FP"A  
SiteFileFetch fileFetch = new SiteFileFetch(bean); HRi
L.
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fileFetch.start(); GFel(cx:K  
} PNaay:a|  
catch(Exception e){e.printStackTrace ();} BO~PT,QrF  
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XVKfl3'%  
} 5]HS^II"  
tZ^Ou89:rG  
ZCB_  
public static void main(String[] args) bzX\IrJpOZ  
{ t?9v^vFR  
new TestMethod(); Q\cjPc0y  
} ~.UrL(l=  
} -[6z 1"*  
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