http断点续传简单实现（java)

/* x_VD9  
**SiteFileFetch.java o.|P7{v}  
*/ uzgQ_  
package NetFox; o +KDK{MD  
import java.io.*; pB0p?D)n  
import java.net.*; O~~
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public class SiteFileFetch extends Thread { vv0+F6 @  
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SiteInfoBean siteInfoBean = null; //文件信息Bean rO3.%B}  
long[] nStartPos; //开始位置 |0N
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long[] nEndPos; //结束位置 MFzJ 8^.1R  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b;k3B7<  
long nFileLength; //文件长度
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boolean bFirst = true; //是否第一次取文件 h}$g}f%$+  
boolean bStop = false; //停止标志 :)=>,XwL8  
File tmpFile; //文件下载的临时信息 R;l;;dC
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DataOutputStream output; //输出到文件的输出流 l\t\DX"s_  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F)n^pT  
public SiteFileFetch(SiteInfoBean bean) throws IOException g:rjt1w`D  
{ F :p9y_W  
siteInfoBean = bean; =&~7Q"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9S_PZH  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); vOQ 3A%/  
if(tmpFile.exists ()) 1=U NA :t<  
{ 68 \73L=  
bFirst = false; hI>vz"J  
read_nPos(); DElrY)3O.  
} Q/zlU@  
else cN3!wE  
{ CyXFuk!R  
nStartPos = new long[bean.getNSplitter()]; 'nRoa7v(  
nEndPos = new long[bean.getNSplitter()]; )Bw}T  
} EJ@&vuDd$  
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} $~
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public void run() ?DrA@;IB  
{ =8V 9E  
//获得文件长度 Cno+rmsfT  
//分割文件 1Wr,E#+C  
//实例FileSplitterFetch Nbvs_>N  
//启动FileSplitterFetch线程 |w].*c}Z  
//等待子线程返回 bGtS! 'I  
try{ H~:EPFi.(  
if(bFirst) u8Ak2:   
{ QCAoL.v  
nFileLength = getFileSize(); Mj<T+Ohz  
if(nFileLength == -1) 67b w[#v  
{ FKBI.}A?!'  
System.err.println("File Length is not known!"); PrqyJ  
} z;Jz^m-  
else if(nFileLength == -2) 9y+0Zj+.  
{ 38E %]*5F  
System.err.println("File is not access!"); m"/ o4  
} L.?QZN%cN  
else ;V0^uB.z  
{ W"n0x8~sV  
for(int i=0;i<nStartPos.length;i++) K 7OIT2-  
{ F87/p  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); urhOvC$a  
} A@<a')#>)  
for(int i=0;i<nEndPos.length-1;i++) c:I %j
m  
{ kt2W7.A5  
nEndPos = nStartPos[i+1]; zI,z<-  
}  <BiSx  
nEndPos[nEndPos.length-1] = nFileLength; A9_}RJ9  
} JnIE6@g<y  
} `n?Rxhkwp  
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//启动子线程 .]w=+~h  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; K1$
   
for(int i=0;i<nStartPos.length;i++) ^D8~s;?  
{ aqEmF  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {/}%[cY
=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ey@ccc*sZ9  
nStartPos,nEndPos,i); i_e%HG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Dv"HFQuF  
fileSplitterFetch.start(); Marx=cNj
 
} UQ#t &  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BUS4 T#D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); VVJIJ9L&C  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", V}X>~ '%  
nEndPos = " + nFileLength); *3\*GatJ  
// fileSplitterFetch[nPos.length-1].start(); FrC)2wX  
PW_"JZ  
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//等待子线程结束 |*$0~mA  
//int count = 0; oy-y QYX  
//是否结束while循环 H/U.Bg 4  
boolean breakWhile = false; > JC"YB  
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while(!bStop) =m;,?("7t3  
{ $0Ys{m  
write_nPos(); [Ob09#B%:5  
Utility.sleep(500); ^r~O*  
breakWhile = true; =P%?{7  
;pj,U!{%s\  
-}u1ZEND  
for(int i=0;i<nStartPos.length;i++) 0`V;;w8  
{ xzHb+1+p  
if(!fileSplitterFetch.bDownOver) [/o BjiBA  
{ z HT#bP:o  
breakWhile = false; #/> a`Ur_  
break; wk#cJ`wG;  
} lK_T%1Gz  
} :%_h'9Qq  
if(breakWhile) U@9v(TfV  
break; &F:%y(;{Y  
<JIqkGeAi  
$R%tD.d3  
//count++; 6of9lO:  
//if(count>4) {53|X=D64  
// siteStop(); 8*;>:g  
} sJ{r+wY  
g/frg(KF  
;nrkC\SYh:  
System.err.println("文件下载结束！"); t$ 97[ay  
} } m"':f  
catch(Exception e){e.printStackTrace ();} .k$Yleg  
}
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~ mzX1[  
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//获得文件长度 #jJ0
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public long getFileSize() >0_{80bdO  
{ Oyb0t|do+  
int nFileLength = -1; +|Izjx]
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try{ `A9fanh  
URL url = new URL(siteInfoBean.getSSiteURL()); %(|-+cLW+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8DX5bB  
httpConnection.setRequestProperty("User-Agent","NetFox"); +p[O|[z  
m>|7&l_  
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int responseCode=httpConnection.getResponseCode(); YYL3a=;`a  
if(responseCode>=400) E 6+ ooB[  
{ P%ThW9^vnj  
processErrorCode(responseCode); ,`PYU[  
return -2; //-2 represent access is error $4*gi&  
} P_5G'[  
@Ko#nDEq  
-/ G#ls|?  
String sHeader; `n@;%*6/  
5g.w"0MkY  
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for(int i=1;;i++) Kn1T2WSAg  
{ `6RccEm  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); TqSjL{l%  
//Utility.log(in.readLine()); X#Ob^E%J  
sHeader=httpConnection.getHeaderFieldKey(i); Qsw
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if(sHeader!=null) D<:zw/IRE  
{ K:A:3~I!NW  
if(sHeader.equals("Content-Length")) c>3j$D+  
{ *2fJdY  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (&u'S+  
break; rp^:{6O  
} re,}}'  
} q6b&b^r+H  
else B`gH({U  
break; I2krxLPd  
} 0dQ\Y]b  
} :wEy""*N0  
catch(IOException e){e.printStackTrace ();} q&}+O  
catch(Exception e){e.printStackTrace ();} i9V,  
/EJy?TON*  
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Utility.log(nFileLength); .s?^y+e_  
:sw@1  
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return nFileLength; :Gzp (@<@e  
} f]mVM(XZN  
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o=  
//保存下载信息（文件指针位置） =Ot_P7'5gv  
private void write_nPos() Gx4{ 9  
{ )TyP{X>  
try{ OG_v[  C5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z_=V6MDM  
output.writeInt(nStartPos.length); 52
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for(int i=0;i<nStartPos.length;i++) J qmL|
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{ ggrkj0  
// output.writeLong(nPos); ;Wa&Dg/5`  
output.writeLong(fileSplitterFetch.nStartPos); Jl6lZd(Np  
output.writeLong(fileSplitterFetch.nEndPos); dt>9mF q  
} \.+:yV<$  
output.close(); X4!Jj*  
} ` @
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catch(IOException e){e.printStackTrace ();} fW[RCd
 
catch(Exception e){e.printStackTrace ();} o\PHs4Ws'7  
} o q6^  
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//读取保存的下载信息（文件指针位置） ;.rY`<|  
private void read_nPos() gzy|K%K  
{ ]vPdj"7  
try{ $pt~?ZZ3-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %mD{rG9  
int nCount = input.readInt(); Gd'_X D  
nStartPos = new long[nCount]; ]rNxvFN*j  
nEndPos = new long[nCount]; gIIF17|Z  
for(int i=0;i<nStartPos.length;i++) 7TU xdI  
{ 1 .[OS  
nStartPos = input.readLong(); X<pNc6  
nEndPos = input.readLong(); 5sj$XA?5  
} M ac?HI  
input.close(); \zwm:@lG  
} s,pg4nst56  
catch(IOException e){e.printStackTrace ();} U_.}V  
catch(Exception e){e.printStackTrace ();} m8G/;V[x  
} fU\;\  
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f! )yE`4-  
private void processErrorCode(int nErrorCode) 'i:lV'  
{ 86!$<!I  
System.err.println("Error Code : " + nErrorCode);  DO9
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} f"NWv!  
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g[uf e<  
//停止文件下载 O(9*
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public void siteStop() gjFQDrz(  
{ #/8 Nav  
bStop = true; QAMcI:5  
for(int i=0;i<nStartPos.length;i++) rhX?\_7o  
fileSplitterFetch.splitterStop(); CJwzjH  
vA[7i*D{w  
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} U.b|3E/^  
} k7L4~W  
//负责部分文件的抓取 "DH>4Q] d  
**FileSplitterFetch.java U!K#g_}  
*/ +x/vZXtOK  
package NetFox; >6@,L+-6r  
&3xda1H  
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import java.io.*; `*`ZgTV  
import java.net.*; T|j=,2_  
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public class FileSplitterFetch extends Thread { I)0_0JXs  
L/%{,7l<^?  
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String sURL; //File URL #XqiXM~^R  
long nStartPos; //File Snippet Start Position y@7CY-1
  
long nEndPos; //File Snippet End Position tp }Bz&V  
int nThreadID; //Thread's ID wlslG^^(!  
boolean bDownOver = false; //Downing is over Fg'{K%t4  
boolean bStop = false; //Stop identical g[~J107%A  
FileAccessI fileAccessI = null; //File Access interface PlT_]p  
~r'ApeI9  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tw.z5  
{ Uyeo0B"  
this.sURL = sURL; wuXH'  
this.nStartPos = nStart; ,t9CP  
this.nEndPos = nEnd; -mo4`F  
nThreadID = id; <]|!quY<*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ac966<
#  
} 8<KC-|y.  
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public void run() C@-cLk  
{ ^P A|RFP  
while(nStartPos < nEndPos && !bStop) Goy[P2m  
{ '"ze Im~  
{i3=N{5b  
#e[r0f?U  
try{ 8YgRJQZ!  
URL url = new URL(sURL); ?P#\CW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); aD6!x3c/  
httpConnection.setRequestProperty("User-Agent","NetFox"); HqV4!o9'  
String sProperty = "bytes="+nStartPos+"-"; Qv;b$by3  
httpConnection.setRequestProperty("RANGE",sProperty); cf*~Gx_l  
Utility.log(sProperty); sqjDh  
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InputStream input = httpConnection.getInputStream(); r?^L/HGc  
//logResponseHead(httpConnection); HzuG- V  
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byte[] b = new byte[1024]; 1]A\@(  
int nRead; YhooD,[.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~3-+~y=o~  
{ jMX|1b  
nStartPos += fileAccessI.write(b,0,nRead); w_LkS/  
//if(nThreadID == 1) 6{g&9~V  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _G/uDP%  
} l <Z7bo  
YG*}F|1  
l2wu>Ar7.  
Utility.log("Thread " + nThreadID + " is over!"); 9+.3GRt7  
bDownOver = true; o"A?Aq  
//nPos = fileAccessI.write (b,0,nRead); h7m$P^=U  
} Z-" NLwt[  
catch(Exception e){e.printStackTrace ();} &XXr5ne~C  
} E>2AG3)  
} X76rme  
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//打印回应的头信息 R+/kx#^  
public void logResponseHead(HttpURLConnection con) vAOThj)  
{ e<~bDFH  
for(int i=1;;i++) %/!f^PIwX  
{ ofgNL .u  
String header=con.getHeaderFieldKey(i); zU4*FXt  
if(header!=null) BgB0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 3u s^\w#  
Utility.log(header+" : "+con.getHeaderField(header)); wARd^Iw  
else X2P8Zq=%a  
break; fN9uSnu  
} Fa{[kJ8z  
} 'I>geW?{QK  
ws U@hqS  
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public void splitterStop() G1I<B  
{ i@%a!].I  
bStop = true; Ty3.u9c4  
} SxkY ;^-U  
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} .5A .[ZY)  
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/* #;;A~d:V  
**FileAccess.java QVl"l'e8  
*//文件访问(定位，写) ~{{7y]3M-  
package NetFox; )t2eg1a:  
import java.io.*; dMI G2log  
wzY{ii  
3]7j,1^  
public class FileAccessI implements Serializable{ X2YBZA  
:*t5?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Nkn2\w  
RandomAccessFile oSavedFile; -"x@V7X  
long nPos; \J-D@b;  
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public FileAccessI() throws IOException FU)=+m  
{ :8]y*j  
this("",0); I(z16wQ  
} xE*.,:,&  
5d-rF:#  
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public FileAccessI(String sName,long nPos) throws IOException IUD@Kf]S  
{ Bt(nm>Ng  
oSavedFile = new RandomAccessFile(sName,"rw"); Sb}=j;F  
this.nPos = nPos; Kv ajk~  
oSavedFile.seek(nPos); \Y6r !D9  
} ,Z8)DC=  
\]3[Xw-$  
 LYyud  
public synchronized int write(byte[] b,int nStart,int nLen) N]F}Z#h  
{ ku#WQL  
int n = -1; M5N#xgR  
try{ m@",Zr`f=  
oSavedFile.write(b,nStart,nLen); ~*e@^Nv)v  
n = nLen; X]=8Oa  
} Rx
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catch(IOException e) u7},+E)+B  
{ E=]|v+#~  
e.printStackTrace (); ss`Sl$  
} vb9C&#  
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return n; FJn.V1  
} nW oh(a  
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} 3KtJT&RuL  
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VL
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/* 3`Xzp  
**SiteInfoBean.java dq0!.gBT2  
*/ /<"ok;Pu7  
package NetFox; K{ntl-D&y  
/.>%IcK  
msQ?V&+<  
public class SiteInfoBean { LG??Q+`l  
1jpft3*x  
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private String sSiteURL; //Site's URL '($$-P\/  
private String sFilePath; //Saved File's Path *JZlG%z  
private String sFileName; //Saved File's Name vx}B
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private int nSplitter; //Count of Splited Downloading File >Sb3]$$  
s@6Jz\<E  
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public SiteInfoBean()
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{//nSplitter的缺省值为5 x0lAJaG  
//default value of nSplitter is 5 pnXwE-c_  
this("","","",5); sD|}?7  
} rE0%R+4?  
5kojh _\  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) oc#hAjB.  
{ b.RFvq5Z  
sSiteURL= sURL; 3PlIn0+LX  
sFilePath = sPath; ?%n"{k?#  
sFileName = sName; oVW>PEgB-  
this.nSplitter = nSpiltter; B&<P>AZ  
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{BgJ=0g?  
} yJ;Qe_up  
$#(j2sL1  
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public String getSSiteURL() .hnq>R\  
{ p6ryUJc6  
return sSiteURL; 45OAJ?N  
} nYe:$t3F=  
DWN9_*{  
n
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public void setSSiteURL(String value) R`B} T<*
  
{ #w:nj1{_  
sSiteURL = value; gEw9<Y  
} 0E)M6 jJ  
nj1PR`AE  
3eB)X2~   
public String getSFilePath() ?]o(cz  
{ L\V`ou  
return sFilePath; -F
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} 9SJSUv:@  
l=x(   
/!qP=ngw9  
public void setSFilePath(String value) 3[8p,wx  
{ C~C`K%7  
sFilePath = value; X,{[R |  
} Av4(=}M}@  
) $0>L5d:  
RE4WD9n  
public String getSFileName() Ty#sY'%  
{ WdB\n/BWB  
return sFileName; Xz9[0;Q  
} >?6HUUQ  
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public void setSFileName(String value) g's!\kr  
{ ~Yc!~Rz  
sFileName = value; D4uAwmc  
} V^rL  
[B+:)i  
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public int getNSplitter() y~su1wUp  
{ G6+6uWvl  
return nSplitter; )P
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} EY:H\4)  
?[P>2oz  
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public void setNSplitter(int nCount) @;N(3| n7  
{ i%, 't  
nSplitter = nCount; xLfv:Rp  
} b*/Mco 9O  
} #=;
vg  
/Gn0|]KI  
X{<taD2~  
/* )dh`aQ%N "  
**Utility.java RD=V`l{Z  
*/ Hsd76z#8  
package NetFox; :,g]Om^  
lJdYR'/Wd  
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public class Utility { xA`j:zn'j  
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public Utility() )[|_q,  
{ /7fd"U$Lh  
3:xKq4?  
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}  sFnR;  
#9F>21UU  
//线程睡眠 E31YkD.A  
public static void sleep(int nSecond) V!>j:"  
{ 9v?@2sOoE  
try{ !2^~ar{2  
Thread.sleep(nSecond); WuFBt=%  
} TdT`Vf  
catch(Exception e) 5jUy[w @  
{ D$*o}*mb  
e.printStackTrace (); Yl:[b{Py  
} {cb<9Fii  
} ;r&Z?B$  
o*ucw3s>  
//日志 4nQ5zwiV  
public static void log(String sMsg) M ?AX:0  
{ 8FZC0j.^DH  
System.err.println(sMsg); p>#q* eU5  
} hUuKkUR+Ir  
}`%ks  
57 Bx-  
public static void log(int sMsg) K=nDC.  
{ fOME&$=O  
System.err.println(sMsg); YbnXAi\y|  
} PxGw5:  
} 9+xO2n  
VJFFH\!`  
r| )45@  
/* ^FkB/j  
**TestMethod.java DvB{N`COd  
*/ '$EyVu
!  
package NetFox; XgM&0lVT  
G%AO%II  
{K6Z.-.`  
public class TestMethod { R/*"N'nH-%  
&43c/TSb  
c))?9H ,e)  
public TestMethod() \nPf\6;M  
{ ///xx/weblogic60b2_win.exe "Dc\w@`E 0  
try{ MGxkqy?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ] $r].,&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); yT5OFD|T  
SiteFileFetch fileFetch = new SiteFileFetch(bean); yU4mS;GX  
fileFetch.start(); }.Z`   
} /BD'{tZ]Sl  
catch(Exception e){e.printStackTrace ();} YD;d*E%t  
0@{0#W3R  
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} *|<~IQg  

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public static void main(String[] args) zy n
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{ `j9\]50Z>  
new TestMethod(); ,UNk]vd  
} R=&-nC5e  
} 8iOHav4  
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