http断点续传简单实现（java)

/* %\ i 7  
**SiteFileFetch.java (1pxQ%yEA  
*/ bnz2\C9^  
package NetFox; ]S6`",+)<f  
import java.io.*; %U&O \GB  
import java.net.*; {/C \GxH+  
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}T?0/N3y&  
public class SiteFileFetch extends Thread { V #0F2GV<,  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &;%z1b>F  
long[] nStartPos; //开始位置 o 26R]  
long[] nEndPos; //结束位置 0Jh^((i*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1XAXokxj  
long nFileLength; //文件长度 Gyak?.@R  
boolean bFirst = true; //是否第一次取文件 :K ^T@F5n  
boolean bStop = false; //停止标志 9U_uw Rv2  
File tmpFile; //文件下载的临时信息 t?:}bw+m  
DataOutputStream output; //输出到文件的输出流 H+`s#'(i_P  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zqDIwfW  
public SiteFileFetch(SiteInfoBean bean) throws IOException gNdEPaaFI  
{ 2FxrMCC  
siteInfoBean = bean; UJXRL   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p9;Oe,Il  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }dl[~iKW  
if(tmpFile.exists ()) |D %m>M6  
{
+0016UgS#  
bFirst = false; NW'rqgG  
read_nPos(); Q2c|sK8  
} W)dQyZ>J  
else (5s$vcK  
{ ieN}Ajl2  
nStartPos = new long[bean.getNSplitter()]; 8IYn9<L  
nEndPos = new long[bean.getNSplitter()]; Q`"gKBN1  
} QkXnXu  
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} iNX%Zk[  
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public void run() e`pYO]Z  
{ Ak`7
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//获得文件长度 :Yi1#  
//分割文件 @5!Mr5;  
//实例FileSplitterFetch y9cDPwi:b  
//启动FileSplitterFetch线程 }fps~R  
//等待子线程返回 CbmT aEaP  
try{ /DG+8u  
if(bFirst) ?v4-<ewD  
{ ~s@PP'!  
nFileLength = getFileSize();  -a``  
if(nFileLength == -1) eSNwAExm  
{ }Ut*Y*  
System.err.println("File Length is not known!"); Lo^0VD!O  
} |H`}w2U[j  
else if(nFileLength == -2) !}Sf?nP#  
{ '->%b  
System.err.println("File is not access!");  |,*N>e  
} :+%"kgJNL  
else 4K_rL{s0U  
{ DJxe3<  
for(int i=0;i<nStartPos.length;i++) Zj@k3y  
{ Arg604V3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~)\9f 1O{^  
} zn| S3c  
for(int i=0;i<nEndPos.length-1;i++) gnjh=anVX1  
{ b&AGVW
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nEndPos = nStartPos[i+1];  `mar-r_m  
} <L4.*  
nEndPos[nEndPos.length-1] = nFileLength; ^I=W<  
} ;D}8acQ  
} {MP8B'r-6  
lSGtbSyDI  
toDv~v  
//启动子线程 3uSj5+@q6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; td*1  
for(int i=0;i<nStartPos.length;i++) i3bH^WwE&k  
{ ?b?6/_W~R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,/?7sHK-0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Y>Oh]?  
nStartPos,nEndPos,i); nQe
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ETt7?,x@  
fileSplitterFetch.start(); G(g`>' m  
} |mx)W}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 97/"5i9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =:)p\{
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [BPK0  
nEndPos = " + nFileLength); ,8~qnLy9  
// fileSplitterFetch[nPos.length-1].start(); 'Z(KE2&?  
?T]` X
 
6n[O8^  
//等待子线程结束 EW$.,%b1  
//int count = 0; ,"MRA  
//是否结束while循环 |;~kHc$W  
boolean breakWhile = false; <SK%W=  
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while(!bStop) ['<Q402:.  
{ 5<Ly^Na:  
write_nPos(); W9i}w&  
Utility.sleep(500);
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breakWhile = true; ?8ZOiY(  
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for(int i=0;i<nStartPos.length;i++) ( (.b&  
{ OvL@@SX |  
if(!fileSplitterFetch.bDownOver) 9T`$gAI  
{ 9%+Nzo(Fd  
breakWhile = false; D<V[:~-o  
break; Y^Of  
} ~3f`=r3/.  
}  fP+RuZ  
if(breakWhile) 4b\R@Knu  
break;
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//count++; QCm93YZs6E  
//if(count>4) "!-  
// siteStop(); |hx"yy'ux  
} NOC8h\s}(  
{RG4m{#9  

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System.err.println("文件下载结束！"); 9'$\G
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} 0m3:!#\  
catch(Exception e){e.printStackTrace ();} mP!=&u fcU  
} kGz0`8URu  
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//获得文件长度 }u3Q*oAGl  
public long getFileSize() ; 9n}P@  
{ %4bGI/\/  
int nFileLength = -1; z%FBHj  
try{ S*aVcyDEP  
URL url = new URL(siteInfoBean.getSSiteURL()); 6_G[&   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yj:<3_-C*  
httpConnection.setRequestProperty("User-Agent","NetFox"); /$z(BX/  
/nPNHO>U  
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int responseCode=httpConnection.getResponseCode(); 8fI]QW  
if(responseCode>=400) nj90`O.K  
{ Z.^DJ9E<1  
processErrorCode(responseCode); ";kwh8wB  
return -2; //-2 represent access is error g6AEMer  
} P
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^ gy"$F3{`  
String sHeader; be<7Vy]j  
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for(int i=1;;i++) g-C)y 06  
{ f9%M:cl  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !t;B.[U *  
//Utility.log(in.readLine()); #<$pl]>}t  
sHeader=httpConnection.getHeaderFieldKey(i);
+.czj,Sq  
if(sHeader!=null) /8cfdP Ba  
{ GbXa=* <-<  
if(sHeader.equals("Content-Length")) l:@`.'-=  
{ 0:1[F!]'b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); S17iYjy#8T  
break; E;o "^[we  
} K/flg|uZ/V  
} -XJXl
}M.  
else q PveG1+25  
break; Qhc>,v)  
} Ii.0Bul  
} OMY^'g%w  
catch(IOException e){e.printStackTrace ();}  T)Uhp  
catch(Exception e){e.printStackTrace ();} ,(;TV_@$  
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Utility.log(nFileLength); Ii.?| u  
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return nFileLength; J<9;Ix8R  
} ov 'g'1}  
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+|w%}/N  
//保存下载信息（文件指针位置） Fkvf[!Ci  
private void write_nPos() ^~7/hm:  
{ l-gNJ=l+K  
try{ BJDSk#!J!{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7l+:gD  
output.writeInt(nStartPos.length); +Oafo|%  
for(int i=0;i<nStartPos.length;i++) d71|(`&  
{ `Eg~;E:  
// output.writeLong(nPos); .T\jEH8E  
output.writeLong(fileSplitterFetch.nStartPos); ,hVDGif  
output.writeLong(fileSplitterFetch.nEndPos); v =]!Po&Q-  
} /8O;Q~a  
output.close(); U
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} ]aZ3_<b  
catch(IOException e){e.printStackTrace ();} %wQE lkB  
catch(Exception e){e.printStackTrace ();} qS!U1R?s  
} fG,)`[eD!_  
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2:jWO_V@  
//读取保存的下载信息（文件指针位置） 6JB*brO  
private void read_nPos() E4cPCQyeH  
{ lzbAx  
try{ bSkr:|A7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ])9
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int nCount = input.readInt(); VprrklZ  
nStartPos = new long[nCount]; ]r(&hqdR  
nEndPos = new long[nCount]; 0s72BcP  
for(int i=0;i<nStartPos.length;i++) WNK)IC~c  
{ th^&wp  
nStartPos = input.readLong(); GlOSCJZ  
nEndPos = input.readLong(); KBg5_+l  
} QFg{.F?3q>  
input.close(); ~7$jW[i  
} 4>NmJrh  
catch(IOException e){e.printStackTrace ();} oXgi#(y  
catch(Exception e){e.printStackTrace ();} ([ODmZHv  
} h|{DIG3  
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private void processErrorCode(int nErrorCode) ?3yrX_Qm{  
{ vo"?a~kY7  
System.err.println("Error Code : " + nErrorCode); )qeed-{  
} WzqYBa  
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//停止文件下载 18WJ*q7:  
public void siteStop() ] L6LB\  
{ nc9sfH3  
bStop = true; ~N]pB]/][  
for(int i=0;i<nStartPos.length;i++) gkFw=Cd  
fileSplitterFetch.splitterStop(); 3y}8|ML  
E#VF7 9L  
=5q_aK#i  
} W690
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} v 8B4%1NE  
//负责部分文件的抓取 -+z8bZ  
**FileSplitterFetch.java zF@/8#  
*/ uhvn1"  
package NetFox; o#QS: '|  
!-~sxa280r  
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import java.io.*; D$fWeG{f  
import java.net.*; #By~gcN  
:zQNnq:|  
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public class FileSplitterFetch extends Thread { Lk]W?  
6FFM-9*|[  
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String sURL; //File URL ` 1vDp.  
long nStartPos; //File Snippet Start Position BV)) #D9  
long nEndPos; //File Snippet End Position vEc<|t  
int nThreadID; //Thread's ID c+ukVn`r  
boolean bDownOver = false; //Downing is over Y(;u)uN_  
boolean bStop = false; //Stop identical ^ pNA_s!S  
FileAccessI fileAccessI = null; //File Access interface
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ziXI$B4-  
{ 6 2LLfD  
this.sURL = sURL; Vtv1{/@+c  
this.nStartPos = nStart; OjurfVw  
this.nEndPos = nEnd; jk{m8YP)E  
nThreadID = id; `4-m$ab  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .\7AJB
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} ~BC~^D&WD  
$ qTv2)W1{  
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public void run() d Z}|G-:  
{ nk"nSXm3SR  
while(nStartPos < nEndPos && !bStop) 'kHa_
  
{ Q#lFt,
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try{ l}~9xa}:D|  
URL url = new URL(sURL); 42=
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SedVp cb+  
httpConnection.setRequestProperty("User-Agent","NetFox"); +R',
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String sProperty = "bytes="+nStartPos+"-"; v9 8s78  
httpConnection.setRequestProperty("RANGE",sProperty); F./P,hhN9  
Utility.log(sProperty); "h:#'y$V  
hu5o{8[  
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InputStream input = httpConnection.getInputStream(); `k-|G2
 
//logResponseHead(httpConnection); a,eEP43dn  
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vlo!D9zsV3  
byte[] b = new byte[1024]; [sl"\3)  
int nRead; ^+}~"nvD  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6o]j@o8V  
{ _xGC0f (  
nStartPos += fileAccessI.write(b,0,nRead); +J3Y}A4W3X  
//if(nThreadID == 1) J~}i}|YC>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]\F}-I[  
} #c(BBTuX  
B:6VD /qC  
0,wmEV!)  
Utility.log("Thread " + nThreadID + " is over!"); XnB-1{a1  
bDownOver = true; %FJB9?9=|  
//nPos = fileAccessI.write (b,0,nRead); #:=*n(GT  
} ok{ F=z  
catch(Exception e){e.printStackTrace ();} ?~X^YxWsY  
} f@ .s(i=z  
} =D Tbz3<  
&%4A3.qE  
gT2k}5d}p  
//打印回应的头信息 .$xTX'  
public void logResponseHead(HttpURLConnection con) A5~OHmeK  
{ nTHCb>,vM  
for(int i=1;;i++) LZ8xh  
{ YJ>P+e\o9  
String header=con.getHeaderFieldKey(i); yJ?=HH?  
if(header!=null) "\qm+g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^TT_BAI  
Utility.log(header+" : "+con.getHeaderField(header)); FO)`&s"&2  
else wu3p2#-Z  
break; wRJ`RKJ-T  
} 9'A^n~JHF  
} [_HOD^  
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public void splitterStop() 8@]vvZ2/gj  
{ XhmUtbs  
bStop = true; vP^V3  
} R(IYb%L  
9-EdT4=r,  
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} s'$3bLcb  
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' BY|7j~  
/* Tua#~.3}J  
**FileAccess.java }Io5&ww:U  
*//文件访问(定位，写) eV\VR !!i  
package NetFox; mA4]c   
import java.io.*; Q
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public class FileAccessI implements Serializable{ !JbWxGN`jn  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 qP72JxT  
RandomAccessFile oSavedFile; x<=R?4@rq  
long nPos; g5t`YcL  
.}n\c%&  
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public FileAccessI() throws IOException 9lB$i2G>Zw  
{ ;]_h")4"c  
this("",0); U4h5K}j4  
} %(>,eee_  
z)%]#QO  
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public FileAccessI(String sName,long nPos) throws IOException {GG;/Ns{f-  
{ ]
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oSavedFile = new RandomAccessFile(sName,"rw"); VJgYXPE `  
this.nPos = nPos; Nq#B4Zx  
oSavedFile.seek(nPos); {tUxRX  
} ?cB26Zrcb  
{=9"WN
 
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public synchronized int write(byte[] b,int nStart,int nLen) dg4q+  
{ FBS]U$1  
int n = -1; 9/dADJe0b  
try{  e,T^
8_>  
oSavedFile.write(b,nStart,nLen); Uwg*kJ3H  
n = nLen; &[kFl\  
} %wN*Hu~E
  
catch(IOException e) 5-POYug  
{ C'a#.LM  
e.printStackTrace (); lbMok/a2o  
} iIc/%< ;  
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return n; -(9TM*)O  
} :Q"p!,X=-  
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} b&*N
 
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/* n= FOB0=  
**SiteInfoBean.java .Xk#Cwm'  
*/ a$$aM2.2  
package NetFox; Dmr3r[  
'?d5L+9  

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public class SiteInfoBean { t_id/  
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MC%!>,tC  
private String sSiteURL; //Site's URL *`V r P  
private String sFilePath; //Saved File's Path R[}fr36>/  
private String sFileName; //Saved File's Name !%/(a)B$^$  
private int nSplitter; //Count of Splited Downloading File mLDuizWI  
ozW\`  
OXF/4Oe  
public SiteInfoBean() =J'&.@Dwz  
{//nSplitter的缺省值为5 ^>#@qMw  
//default value of nSplitter is 5 xPzBbe  
this("","","",5); 
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} @P<aTRy,f  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) A5RM&y  
{ o>A']+`Eu  
sSiteURL= sURL; t4+bRmS`_  
sFilePath = sPath; nf
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sFileName = sName; ;Hn>Ew  
this.nSplitter = nSpiltter; [midNC+,  
v;d3uunqv  
d^I:{Ii'  
} c=33O,_  
a|Wrc)UR  
^tI4FQ>Y  
public String getSSiteURL() x]vyt}oCmk  
{ Q$A;Fk}-  
return sSiteURL; .7> g8  
} k\A4s
j  
jfpbD /  
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public void setSSiteURL(String value) lfqsoIn;  
{ /~pB_l  
sSiteURL = value; p%IVWeZnx  
} 9b)'vr*Hy7  
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public String getSFilePath() ksF4m_E>YB  
{ rAS2qt  
return sFilePath; Vn?|\3KY  
} cQ(,M  
.cB>ab&  
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public void setSFilePath(String value) scZ&}Ni  
{ <%S[6*6U  
sFilePath = value; fK+[r1^  
} rS_pv=0S  
CmdPa!4)  
';I(#J6  
public String getSFileName() [uFv_G{H  
{ 'W/AYF^5  
return sFileName; +{WZpP},v  
} R_b)2FU1y  
ZV$!dHW/  
tD> qHR  
public void setSFileName(String value) 6o~g3{O
w  
{ %9_jF"  
sFileName = value; L\\'n )  
} fnK H<  
L6J.^tpO  
9eEA80i7  
public int getNSplitter() ET\rd5Po  
{ jV(b?r)eT{  
return nSplitter; D{M&>.  
} (VBO1f  
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public void setNSplitter(int nCount) DiSU\?N2'  
{ |j}%"wOh  
nSplitter = nCount; pPJE.[)V/  
} a<P?4tbF  
} RU\MT'E>(  
?J6\?ct4  
Qk].^'\  
/* rDC=rG  
**Utility.java >g2Z t;*@w  
*/ Q'0:k{G  
package NetFox; oPrK{flm  
LT]YYn($  
IQ5'4zQg=  
public class Utility { _A6e|(.ll  
GW0e=Y=LR  
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public Utility() Q
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{ bH.f4-.u>)  
fn Pej?f:  
5wbR}`8  
} q=
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#fq&yjl#A  
//线程睡眠 6d;RtCENo  
public static void sleep(int nSecond) '@WS7`@-y  
{ Je=k.pO1  
try{ <UbLds{+Uo  
Thread.sleep(nSecond); \6vr)1~N>  
} -8z@FLUK-  
catch(Exception e) W.?EjEx  
{ pW-aX)\DR  
e.printStackTrace (); BP8jReX^  
} 3Cg0^~?6-  
} _o{w<b&  
rM)#}eZK!  
//日志 1j+RXb\<  
public static void log(String sMsg) 6<{SbE|G{  
{ 4td9=dNA+l  
System.err.println(sMsg); ~U1M-<IX  
} i(0%cNP7  
7a4h7/  
sg4TX?I   
public static void log(int sMsg) $8fJDN  
{ ~-#8j3 J;  
System.err.println(sMsg); BZk0B?  
} 8Wx7%@^O  
} !%>(O@~"|  
%!OA/7XbG  
$q0i=l&$&  
/* P5`BrY,hZ  
**TestMethod.java b.QL\$a &  
*/ kw5`KfG9  
package NetFox; 7xCm"jgP  
O{wt0 \P  
'h`)6{  
public class TestMethod { H+ 7Fw'u  
YeV
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>?r8D48`  
public TestMethod() $uYfy<  
{ ///xx/weblogic60b2_win.exe 0[7tJbN  
try{ !^qpV7./l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); HA3d9`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~jMfm~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^) 5*?8#  
fileFetch.start(); dd!Q[]$ }  
} C$^WW}S  
catch(Exception e){e.printStackTrace ();} AO]1`b:  
KWH:tFL.  
8P*wt'Q$  
} TH? wXd\  
C*Wyw]:r  
AQgm]ex<  
public static void main(String[] args)  t`'5|  
{ mZ#h p}\.  
new TestMethod(); !.[H!-V.  
} _PGS"O?j  
} ]I(<hDuRp  
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