http断点续传简单实现（java)

/* q~Ud>{  
**SiteFileFetch.java *)Y;`Yg$  
*/ am=56J$ig  
package NetFox; DN+iS  
import java.io.*; /W;;7k  
import java.net.*; ck;owGlT  
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6 J#C  
public class SiteFileFetch extends Thread { yq2Bz7P  
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t{
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SiteInfoBean siteInfoBean = null; //文件信息Bean a v/=x  
long[] nStartPos; //开始位置 ie)Qsw@  
long[] nEndPos; //结束位置 1FuChd  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 CBc}N(9  
long nFileLength; //文件长度 8w$cj'  
boolean bFirst = true; //是否第一次取文件 z&eJ?wb  
boolean bStop = false; //停止标志 jU=)4nx  
File tmpFile; //文件下载的临时信息 drH!?0Dpg  
DataOutputStream output; //输出到文件的输出流 }k%>%xQ.  
}rN"H4)  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @Q'5/q+  
public SiteFileFetch(SiteInfoBean bean) throws IOException Jv5G:M5+~  
{ E3'6lv'  
siteInfoBean = bean; aw~OvnX E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Z@>>ZS1Do  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U6{ RHS[  
if(tmpFile.exists ()) IBR;q[Dj}  
{ k,H4<")H  
bFirst = false; wvfCj6}S&  
read_nPos(); N24+P5  
} i^=an?}/  
else R,(^fM  
{ !R-UL#w9W'  
nStartPos = new long[bean.getNSplitter()]; BR|dW
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nEndPos = new long[bean.getNSplitter()]; ~{HA!C#  
} r J&1
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{KR/
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} bf3)^ 49}  
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public void run() 8s|r'  
{
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//获得文件长度 ^s%Qt  
//分割文件 S_^
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//实例FileSplitterFetch 3p7*UVR"  
//启动FileSplitterFetch线程 thOCzGJ$  
//等待子线程返回 p@P[pzxI  
try{ X,~8) W  
if(bFirst) 4}gwMjU-B  
{ Odagaca  
nFileLength = getFileSize(); GG7N!eZ  
if(nFileLength == -1) seJc,2Ex  
{ <>-UPRwqI  
System.err.println("File Length is not known!"); -i9/1.Z  
} bju0l[;=  
else if(nFileLength == -2) S6cSeRmw  
{ I@.qon2V  
System.err.println("File is not access!"); KExfa4W 3{  
} &%^[2^H8"  
else z8A`BVqI  
{ 6~
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for(int i=0;i<nStartPos.length;i++) 7%JXVP}A  
{ W0R6<- 1
 
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Y~Zg^x2  
} ])e6\)  
for(int i=0;i<nEndPos.length-1;i++) i`
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{ F|V?Z  
nEndPos = nStartPos[i+1]; 9)
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} kQ|}"Tw7  
nEndPos[nEndPos.length-1] = nFileLength; |s|RJA1  
} X~lOFH;}q  
} guBOR0x`  
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1V
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//启动子线程 ${`\In_?O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 5-n N8qs  
for(int i=0;i<nStartPos.length;i++) 3fpX  
{ <OpiD%Ctx  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {Ke3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), NJn~XCq  
nStartPos,nEndPos,i); x'}{^'}/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G$ipWi  
fileSplitterFetch.start(); WpRi+NC}ln  
} -^C;WFh8)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IhUuL0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); G>cTqD6gT  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `lr\V;o!  
nEndPos = " + nFileLength); Jg^tr>I~  
// fileSplitterFetch[nPos.length-1].start(); SxMh '  
I#9A\.pO  
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//等待子线程结束 A
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//int count = 0; @"Do8p!*(6  
//是否结束while循环 )TG\P,H9  
boolean breakWhile = false;
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while(!bStop) R(ay&f%E  
{ 2N`Vx3  
write_nPos(); N/]TZu~k z  
Utility.sleep(500); =T;%R^@  
breakWhile = true; ^k~{6S,  
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for(int i=0;i<nStartPos.length;i++) +STT(bMn  
{ R0{+Xd  
if(!fileSplitterFetch.bDownOver) 61CNEzQ  
{ HnZrRHT0  
breakWhile = false; B7va#'ne4{  
break; _k _F  
} kf
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} E/Y.f  
if(breakWhile) wHdq:,0-!  
break; 0W#.$X5  
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@zSoPDYv,  
//count++; H`m|R  
//if(count>4) dc"Vc 3)  
// siteStop(); Onby=Y o6  
} DH@*O
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System.err.println("文件下载结束！"); {P(IA2J'S  
} 1,BtOzuRo  
catch(Exception e){e.printStackTrace ();} QZ%_hvY[%>  
} 5h1FvJg  
o{m$b2BW  
2i8'*L+j  
//获得文件长度 Eo)n( Z9  
public long getFileSize() u]CW5snz  
{ hNSV}~h  
int nFileLength = -1; sLb[ZQ;j  
try{ H#G'q_uHH  
URL url = new URL(siteInfoBean.getSSiteURL()); PJ9JRG7j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H?M8j] R-)  
httpConnection.setRequestProperty("User-Agent","NetFox"); r's4-\  
7RTp+FC]  
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int responseCode=httpConnection.getResponseCode(); d(42ob.Tr  
if(responseCode>=400) O" n/.`  
{ P#"vlNa  
processErrorCode(responseCode); %F1 Ce/  
return -2; //-2 represent access is error 7t
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} 2A {k>TjQ  
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String sHeader; L@9"6&  
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for(int i=1;;i++) 5H`k$[3V  
{ ?ZE1>L7e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8x[q[  
//Utility.log(in.readLine()); $UgM7V$  
sHeader=httpConnection.getHeaderFieldKey(i); zd"o #(sv  
if(sHeader!=null) 9kQ~)4#  
{ !2$O^ }6"  
if(sHeader.equals("Content-Length")) 67')nEQ9  
{ sR ~1J4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =AGsW  
break; ci6j"nKci  
} xsV(xk4  
} $yHlkd`Y  
else teQ%t~PJ-&  
break; pX*Oc6.0mu  
} kce+aiv|u  
} Dm"GCV  
catch(IOException e){e.printStackTrace ();} E;9SsA  
catch(Exception e){e.printStackTrace ();} 7YkxIzE  
n<y!@p^X  
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Utility.log(nFileLength); \{P(s:  
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return nFileLength; sq\oatMw[  
} j^ex5A.& &  
/@Y/(+DE  
O.
 V!L  
//保存下载信息（文件指针位置） O5LB&s  
private void write_nPos() ie=tM'fb  
{ (KK9/k  
try{ 7P.C~,+D%P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); YSs9BF:a  
output.writeInt(nStartPos.length); lX;2~iW{/  
for(int i=0;i<nStartPos.length;i++) Nq"/:3@4  
{ xW#r)aN]p  
// output.writeLong(nPos); 2_R'Kl![  
output.writeLong(fileSplitterFetch.nStartPos); N?ky2wG  
output.writeLong(fileSplitterFetch.nEndPos); q;InFV3rv  
} wBA[L}   
output.close(); ;sS N  
} CT6a  
catch(IOException e){e.printStackTrace ();} m("! M~1  
catch(Exception e){e.printStackTrace ();} oost}%WxN  
} Sz.jv#Y  
=pF 6  
#,0%g1  
//读取保存的下载信息（文件指针位置） a)`b;]+9  
private void read_nPos() 0' @^PzX  
{ ~ubGx  
try{ x$cs_
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ezY _7  
int nCount = input.readInt(); 4M}u_}9  
nStartPos = new long[nCount]; F9^
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nEndPos = new long[nCount]; N;9@-Tb  
for(int i=0;i<nStartPos.length;i++) wh<+.Zp  
{
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nStartPos = input.readLong(); e3yBB*@  
nEndPos = input.readLong(); w<lHY=z E  
} 3BDAvdJ4.  
input.close(); {r#2X1  
} EdhT;!  
catch(IOException e){e.printStackTrace ();} )ZEUD] X  
catch(Exception e){e.printStackTrace ();} tT ~}lW)Y  
} [kDjht|$>  
>c|u|^3zt  
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private void processErrorCode(int nErrorCode) f.!)O@HzH  
{ Rq%g5lK  
System.err.println("Error Code : " + nErrorCode); ?PO~$dUc]  
} +FP*RNM  
k^
}8=,j}  
XnHcU=~q  
//停止文件下载 \`-/\N  
public void siteStop() >sv|  
{ -%I]Q9  
bStop = true; }:5AB93(  
for(int i=0;i<nStartPos.length;i++) ;3s_#L  
fileSplitterFetch.splitterStop(); L 5J=+k,  
=cs;avtL  
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} F0t!k>  
} !?`5r)K  
//负责部分文件的抓取 ZTfs&5  
**FileSplitterFetch.java D0Oh,Fe#M\  
*/ hu%UEB  
package NetFox; 3)^-A4~E  
: |#Iw  
q+>J'UGb  
import java.io.*; %=xR$<D  
import java.net.*; o$FqMRep  
UN>!#Ji:$  
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public class FileSplitterFetch extends Thread { +R@5e+auQ.  
K'+GK S7.  
*Em 9R  
String sURL; //File URL [ Lt1OdGl  
long nStartPos; //File Snippet Start Position .iNPLz1  
long nEndPos; //File Snippet End Position Uc/MPCqZ  
int nThreadID; //Thread's ID 'j6PL;~c  
boolean bDownOver = false; //Downing is over qsk8#  
boolean bStop = false; //Stop identical *y9 iuJ}  
FileAccessI fileAccessI = null; //File Access interface 9&q<6TZz  
O,>1GKw"\  
ja3wXz$2  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z"<aS&GH  
{ kz\ D-b  
this.sURL = sURL; j(F
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this.nStartPos = nStart; Yv\.QrxPm  
this.nEndPos = nEnd; awQf$  
nThreadID = id; .?UK`O2Q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 vE0Ty9OH"]  
} m=b~Wf39  
h7c8K)ntnf  
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public void run() uvz}qH@j/Q  
{ V'sp6:3*\  
while(nStartPos < nEndPos && !bStop) ??5qR8n.  
{ ,'?%z>RZm  
7^P!@o$v!  
Pou-AzEP$  
try{ F2WUG  
URL url = new URL(sURL); )T/"QF}<T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {y0#(8-&  
httpConnection.setRequestProperty("User-Agent","NetFox"); n|dLK.Q  
String sProperty = "bytes="+nStartPos+"-"; W|_ @ju  
httpConnection.setRequestProperty("RANGE",sProperty); H)(@A W+-  
Utility.log(sProperty); P/5bNK!  
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InputStream input = httpConnection.getInputStream(); Y[k%<f  
//logResponseHead(httpConnection); B- =*"H?q  
xwhH_[  
2qLRcA=R  
byte[] b = new byte[1024]; SV}
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int nRead; p(in.Xz  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >H?l[*9  
{ 9=7),`$  
nStartPos += fileAccessI.write(b,0,nRead); j38>,9u,  
//if(nThreadID == 1) XP~bmh,T,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &@u;xc| v  
} -fFM-gt^t  
o6,$;-?F_  
jE|Ju:}&  
Utility.log("Thread " + nThreadID + " is over!"); D[U[D  
bDownOver = true; &;S.1tg  
//nPos = fileAccessI.write (b,0,nRead); xZZW*d_b  
} Oaf!\z}  
catch(Exception e){e.printStackTrace ();} I9O!CQCTt  
} NXb_hF  
} 0l#gS;  
_\waA^ F  
-Zc 6_]F|  
//打印回应的头信息 RL7OFfMe  
public void logResponseHead(HttpURLConnection con) %m$TV@  
{ Cg<:C?>!p  
for(int i=1;;i++) /{Ksi+
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{ .q$HL t  
String header=con.getHeaderFieldKey(i); *ci,;-*C  
if(header!=null)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); )_N|r$i\  
Utility.log(header+" : "+con.getHeaderField(header)); n=!]!'h\:  
else flDe*F^  
break; #D~atgR
 
} >Vz Gx(7q  
} (~}IoQp>  
%tEjf 3  
[<`K%1GQ  
public void splitterStop() ieXhOA  
{ ~Fp,nE-B  
bStop = true; |Z'NMJU  
} HTiqErD2_  
|!:ImX@  
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} n:d]Z2
b  
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ZRN*.  
/* (]7&][  
**FileAccess.java T^.;yU_B?  
*//文件访问(定位，写) MUsF/1  
package NetFox; I:l<t*  
import java.io.*; \o3)\ e]o  

,tJ%t#  
0Ou;MU*v  
public class FileAccessI implements Serializable{ H1X38  
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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 7.)e4  
RandomAccessFile oSavedFile;
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long nPos; tj/X7|  
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public FileAccessI() throws IOException D#|+PG7  
{ $/^DY&  
this("",0); F0h`>{1%  
} rmXxid  
;BzbWvBo  
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public FileAccessI(String sName,long nPos) throws IOException N"Y)  
{ =>nrU8x  
oSavedFile = new RandomAccessFile(sName,"rw"); IGz92&y  
this.nPos = nPos; ;v%Fw!b032  
oSavedFile.seek(nPos); HnU; N S3J  
} (3 xCW  
;mH O#  
<>JN&#3?  
public synchronized int write(byte[] b,int nStart,int nLen) NFq&a i  
{ .y'iF>QQ\  
int n = -1; 6\>S%S2:  
try{ L&V;Xvbu%  
oSavedFile.write(b,nStart,nLen); 70bI}/u  
n = nLen; dl_ h0  
} 
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catch(IOException e) OI0#@_L&  
{ 2z9\p%MX  
e.printStackTrace (); _K"|}bM  
} 8|kr|l  
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return n; {(;dHF%{  
} mLApF5Hy  
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} IB9[Lx  
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cojtQD
6  
/* (T;4'c  
**SiteInfoBean.java ?/ xk  
*/ gzfs9e  
package NetFox; Yd]y`J?#  
>i^8K U  
On x[}x  
public class SiteInfoBean { zAT7^q^  
wh4ik`S 1  
;UuCSfs{  
private String sSiteURL; //Site's URL 7<{g+Q~7*  
private String sFilePath; //Saved File's Path p!qV!:  
private String sFileName; //Saved File's Name Ip#BR!$n  
private int nSplitter; //Count of Splited Downloading File $|+q9o\  
Ia_I~ U$  
*Ju$A  
public SiteInfoBean() K.3)m]dCl  
{//nSplitter的缺省值为5 %:i; eUKR  
//default value of nSplitter is 5  2fZVBj  
this("","","",5); M-inlZNR  
} XaT9`L<  
>YP6/w,e  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) h| q!Qsnj'  
{ w`_cmI  
sSiteURL= sURL; K_/-mwA v  
sFilePath = sPath;
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sFileName = sName; o,o,(sII  
this.nSplitter = nSpiltter; n^F:p*)Q%  
:)f/>-   
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} )1 ]P4  
4n6EkTa  
/ZC/yGdIS_  
public String getSSiteURL() -L%J,f[&,  
{ X!=E1TL  
return sSiteURL; ]2O52r  
} dkT
ewT
6'  
M"cB6{st[  
JjBG9Rp{  
public void setSSiteURL(String value) QwF\s13  
{ U*Q1(C  
sSiteURL = value; Dn{ hU$*  
} 5=< y%VF  
@9-/p^n1  
2.''Nt6|  
public String getSFilePath() fL^+Qb}  
{ >q W_%  
return sFilePath; >K]s)VuWR  
} 'Xj9sAB  
&f12Q&jY7  
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public void setSFilePath(String value) P#e1?  
{ M#<U=Ha  
sFilePath = value; uZ[7[mK}n7  
} P .I<.e  
lw/zgR#|  
,
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public String getSFileName() yb 7  
{ &
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return sFileName; y3!r;>2k=  
} Fk&W*<}/;  
oWCy%76@  
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public void setSFileName(String value) j?!BHNs  
{ ~Sq!P  
sFileName = value;  :{#%_^}k  
} \}CQo0v  
|%wgux`z  
lqD.epm  
public int getNSplitter() t9zPUR  
{ f~U~f}Uw4  
return nSplitter; AH*{Bi[vX  
} l,z# :k  
_hM #*?}v  
wUUDq?!k\  
public void setNSplitter(int nCount) IZr~h9  
{ [VvTR#^  
nSplitter = nCount; 7d9kr?3(U  
} &G#LQl  
} 3Z,J&d`[  
+TA'P$j  
\BIa:}9O  
/* +w'"N  
**Utility.java !_zp'V]?  
*/ x2-i1#j`;  
package NetFox; G8]DK3#  
j$2rU'  
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public class Utility { +ZuT\P&kR5  
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ixK&E#  
public Utility() XUI9)Ne  
{ $-HP5Kj(k-  
F0yvV6;  
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-[j)  
} ,tt .oF|  
5m.{ayE  
//线程睡眠 N^G $:GC  
public static void sleep(int nSecond) _(#HQd,i  
{ <K^{36h  
try{ HC%tJ:G  
Thread.sleep(nSecond); hxwo<wEg  
} B=0U^wL  
catch(Exception e) :5Y yI.T  
{ A&HN7C%X  
e.printStackTrace (); +[LG>  
} U;o$=,_p  
} bn$('  
z
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//日志 'hEvW  
public static void log(String sMsg) VnZRsFY<^  
{ ].=~C"s,a  
System.err.println(sMsg); #3b_#+,  
} U9?fUS  
% oPt],>  
{P'_s]B)  
public static void log(int sMsg) 5y 9(<}z  
{ @W4tnM,#  
System.err.println(sMsg); .G ^-.p  
} #hp7@ Tu  
} 'H19@b5rx  
*En29N#a{  
7H$I9e  
/* [uJfmrEH  
**TestMethod.java IE)$.%q;)  
*/ Q9i&]V[`  
package NetFox; .Y
w  
d4#CZv[g/  
:,@"I$>*/  
public class TestMethod { jOkc'  
QR ?JN\%?  
t2L}  
public TestMethod() QLs9W&PG  
{ ///xx/weblogic60b2_win.exe ~wtK(U  
try{ uW%(ySbq  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (G>S`B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .S5%Qa [uW  
SiteFileFetch fileFetch = new SiteFileFetch(bean); h_( #U)z_3  
fileFetch.start(); #Nv^F  
} yt5Sy  
catch(Exception e){e.printStackTrace ();} ?Iin/<y  
O(R1D/A[  
"jUM}@q5  
} |;(95  
P&>!B,f  
q&DM*!Jq  
public static void main(String[] args) wV604eO(  
{ N4[`pXM6
 
new TestMethod(); .jXD0~N8q  
} Kl Kk?6>  
} @QN(ouqQ  
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