http断点续传简单实现（java)

/* TO#Pz.)>B6  
**SiteFileFetch.java h<l1U'Bn7  
*/ /-M@[p&  
package NetFox; ,kM)7!]N  
import java.io.*; /X*oS&-M  
import java.net.*; #x@eDnb_  
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public class SiteFileFetch extends Thread { ccJM>9  
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SiteInfoBean siteInfoBean = null; //文件信息Bean z\!K<d"Xv  
long[] nStartPos; //开始位置 X[3}?,aqL  
long[] nEndPos; //结束位置 Ip *g'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 U5r}6D!)  
long nFileLength; //文件长度 cj$6  
boolean bFirst = true; //是否第一次取文件 svhI3"
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boolean bStop = false; //停止标志 kxB.,'  
File tmpFile; //文件下载的临时信息 gP}+wbk  
DataOutputStream output; //输出到文件的输出流 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5/0j}_pP  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1DJekiWf  
{ (p)!Mq "^  
siteInfoBean = bean; sM2MLh'D  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Xrqx\X  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $'wq1u  
if(tmpFile.exists ())  %Y nmuZ  
{ dA~ 3>f*b_  
bFirst = false; 5K%Wa]W  
read_nPos(); {MBTP;{*~  
} }"s;\?a  
else  #ToK$8  
{ lS5ny  
nStartPos = new long[bean.getNSplitter()]; <i. apBH  
nEndPos = new long[bean.getNSplitter()]; /
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} V"KS[>>f  
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} SZU \i*  
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public void run() Kq6jw/T  
{ mI1H!  
//获得文件长度 p*3; hGp6  
//分割文件 Sv[5NZn0&  
//实例FileSplitterFetch &(pjqV  
//启动FileSplitterFetch线程 Lxl_"kG  
//等待子线程返回 I:j3sy  
try{ ~mz%E
 
if(bFirst) @mQ:7-,~  
{ P ,mN >  
nFileLength = getFileSize(); Gu0 ,)jy\  
if(nFileLength == -1) # TkR  
{ QO;4}rq  
System.err.println("File Length is not known!"); KW3+luI6  
} Li{~=S@N*  
else if(nFileLength == -2) 2[yBD-":  
{ N:5[,O<m_  
System.err.println("File is not access!"); )6X.Nfkb^k  
} -7qIToO.  
else fz_nsVD  
{  ZI>km?w  
for(int i=0;i<nStartPos.length;i++) Q;/a F`  
{ LV{Q,DrP  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >]D4Q<TY  
} @* ust>7  
for(int i=0;i<nEndPos.length-1;i++) e /K#>,  
{ J5M+FwZq  
nEndPos = nStartPos[i+1]; ?\=/$Gt  
} `CE^2  
nEndPos[nEndPos.length-1] = nFileLength; J>vMo@  
} <'U]`Lp  
} Qx3eLfm  
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,\)a_@@k  
//启动子线程 +>f<EPGn  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Q9F)  
for(int i=0;i<nStartPos.length;i++) W&Y"K)`  
{ VyLH"cCv  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eDKxn8+(H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [#^#+ |{\  
nStartPos,nEndPos,i); >h~IfZU1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `|Z}2vo;j  
fileSplitterFetch.start(); kma?v B  
} coE&24,0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .x83Ah`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Pt,
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", CB\{!  
nEndPos = " + nFileLength); z`@^5_  
// fileSplitterFetch[nPos.length-1].start(); 7E$&2U^Js  
iP@6hG`:  
iPG0o %  
//等待子线程结束 *~XA'Vw!  
//int count = 0; Kb;dKQ  
//是否结束while循环
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boolean breakWhile = false; $rB3m~c|  
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3 fj  
while(!bStop) p/6zEZ*  
{ p zw8T  
write_nPos(); Dr<='Ux[5  
Utility.sleep(500); k`KGB  
breakWhile = true; <!d"E@%v@  
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j V3)2C}  
for(int i=0;i<nStartPos.length;i++) h!@,8y[B  
{ JtKp(k&  
if(!fileSplitterFetch.bDownOver) <i?a0  
{ ^Mkk@F&1  
breakWhile = false; `TqSQg_l  
break; Qq& W3  
} w0m^ &,;#  
}
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if(breakWhile) R6;Phdh<>  
break; b,H[I!. %  
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//count++; 6aO2:|:yP  
//if(count>4) gO?44^hMe  
// siteStop(); @LE[ac  
} f7urJ'!V  
X?r48l??  
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System.err.println("文件下载结束！"); 0rSIfYZa  
} \`.F\Z  
catch(Exception e){e.printStackTrace ();} E8\XNG)V4  
} -[7O7'  
#U7_a{cn"M  
)P&9A)8  
//获得文件长度 y8Xv~4qQW  
public long getFileSize() 5i6
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{ I_)*)d44_  
int nFileLength = -1; `m@U!X  
try{ : 9!%ZD  
URL url = new URL(siteInfoBean.getSSiteURL()); "bQ[CD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jF"YTr6  
httpConnection.setRequestProperty("User-Agent","NetFox"); >cMd\%^t  
 P\m7 -  
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int responseCode=httpConnection.getResponseCode(); w?vVVA  
if(responseCode>=400) .Ce8L&cU  
{ OWjJxORB  
processErrorCode(responseCode); . v)mZp  
return -2; //-2 represent access is error I+ l%Sn#\  
} I
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String sHeader; mdih-u(T|  
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for(int i=1;;i++) F!!N9VIC  
{ H!IshZfktn  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2C^B_FUg|]  
//Utility.log(in.readLine()); LE^G&<!  
sHeader=httpConnection.getHeaderFieldKey(i); [s1pM1x  
if(sHeader!=null) 0'Z\O   
{ SkNre$>t{  
if(sHeader.equals("Content-Length")) j=+"Qz/hr_  
{ ^H'a4G3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); EpPf_ \o  
break; ^4Am %yyT  
} `b5 @}',  
} yBed kj  
else we7c`1E  
break; .aOnGp  
} {i~8 :  
} )vB2!H/  
catch(IOException e){e.printStackTrace ();} y %8op:'  
catch(Exception e){e.printStackTrace ();} H5>hx{  
/ jTT5  
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Utility.log(nFileLength); h~Q)Uy5N(D  
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return nFileLength; &O\(;mFc  
} XEM'}+d  
+V862R4,o  
q~K(]Ya/  
//保存下载信息（文件指针位置） !G5a*8]  
private void write_nPos() &F$:Q:* *  
{ d5I f"8`@  
try{ qa >Ay|92e  
output = new DataOutputStream(new FileOutputStream(tmpFile)); xFv;1Q
 
output.writeInt(nStartPos.length); JOnyrks  
for(int i=0;i<nStartPos.length;i++) 4JIYbb-a'  
{ lG<hlYckv  
// output.writeLong(nPos); I,6/21kO  
output.writeLong(fileSplitterFetch.nStartPos); p4u5mM  
output.writeLong(fileSplitterFetch.nEndPos); "I- w  
} #!J(4tXny  
output.close(); ^cvl:HOog  
} Br>Fpe$q4  
catch(IOException e){e.printStackTrace ();} u~zs* qp  
catch(Exception e){e.printStackTrace ();} lb'Cl3H  
} `'_m\uo  
7\ SUr9[  
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//读取保存的下载信息（文件指针位置） M&Y .;  
private void read_nPos() ITuq/qts]A  
{ ~=r^3nZR/J  
try{ donw(_=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); nx":"LFI  
int nCount = input.readInt(); v0*N)eqDGd  
nStartPos = new long[nCount]; %!Q`e79g8  
nEndPos = new long[nCount]; N@o?b  
for(int i=0;i<nStartPos.length;i++) \g)Xt?w0Wo  
{ RH;:9_*F  
nStartPos = input.readLong(); g\oSG)  
nEndPos = input.readLong(); 3#kitmV  
} g\A y`.s  
input.close(); YMpf+kN  
} \6|/RFT  
catch(IOException e){e.printStackTrace ();} ,FQdtNMap  
catch(Exception e){e.printStackTrace ();} OvL\u{(<F  
} pj|pcv^  
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private void processErrorCode(int nErrorCode) q(^Q3  
{ ]Z<_ "F  
System.err.println("Error Code : " + nErrorCode); c/W=$
3  
} RWq{Ff}Hk  
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//停止文件下载 iGXI6`F"  
public void siteStop() `xS{0P{uj  
{ t-%Q`V=[  
bStop = true; $9 p!Y}  
for(int i=0;i<nStartPos.length;i++) &(rWwOo6  
fileSplitterFetch.splitterStop(); ri~<~oB2:  
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} {C*\O)Gep  
} u9-nt}hGYM  
//负责部分文件的抓取 "7%:sty  
**FileSplitterFetch.java omZO+=8Q  
*/ -PB[-CX  
package NetFox; [^H"FA[  
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import java.io.*; 8Q`WB0E<|  
import java.net.*; [jx0-3s:X  
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public class FileSplitterFetch extends Thread { \~rl
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String sURL; //File URL @!=\R^#p  
long nStartPos; //File Snippet Start Position {kI#A?M  
long nEndPos; //File Snippet End Position f}%D"gz  
int nThreadID; //Thread's ID JM$.O;y -  
boolean bDownOver = false; //Downing is over nHFrG =o,  
boolean bStop = false; //Stop identical "LhUxnll  
FileAccessI fileAccessI = null; //File Access interface &Jc_Fc(M  
-XoPia2  
pI`?(5iK6|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~.Ik#At  
{ G* %t'jX9  
this.sURL = sURL; wl=61Mb  
this.nStartPos = nStart; -OZ 5vH0  
this.nEndPos = nEnd; ^:, l\Y  
nThreadID = id; RH0>ZZR  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 c2l_$p  
} i yYJR  
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public void run() =64r:E  
{ Eq%@"-mo  
while(nStartPos < nEndPos && !bStop) D,l,`jv*  
{ %9C@ Xl  
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E&$_`m;  
try{ v'2[[u{7*  
URL url = new URL(sURL); 4\t1mocCSN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *TW=/+j  
httpConnection.setRequestProperty("User-Agent","NetFox"); $ 0|a;  
String sProperty = "bytes="+nStartPos+"-"; U09.Y  
httpConnection.setRequestProperty("RANGE",sProperty); q
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Utility.log(sProperty); +H/jK@  
7
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InputStream input = httpConnection.getInputStream(); K?x,T8<aW  
//logResponseHead(httpConnection); SM0M%  
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byte[] b = new byte[1024]; 1&=0Wg0ig  
int nRead; ;.sl*q1A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) t,)N('m}=  
{ 0X2@CPIFf  
nStartPos += fileAccessI.write(b,0,nRead); ij5g^{_T;8  
//if(nThreadID == 1) 8$N8}q%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NMO-u3<6.  
} w JwX[\
 
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Utility.log("Thread " + nThreadID + " is over!");  q}Z3?W  
bDownOver = true; T70QJ=,  
//nPos = fileAccessI.write (b,0,nRead); k#TYKft  
} %WG9 dYdS  
catch(Exception e){e.printStackTrace ();} iJFs0?*  
} .ujT!{>v/  
} {@}?k s5  
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//打印回应的头信息 UnDgu4#R`A  
public void logResponseHead(HttpURLConnection con)
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{ /(I*,.d  
for(int i=1;;i++) 8qi
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{ \b'xt  
String header=con.getHeaderFieldKey(i); inPJ2uBD\^  
if(header!=null) C) QKPT  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); EY`H}S!xy  
Utility.log(header+" : "+con.getHeaderField(header)); g_*T?;!.U  
else 8?t"C_>*e  
break; /NT[ETMk+  
} XALI<ZY  
} *MNHT`Y^o  
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public void splitterStop() 'J*<iA*W  
{ BIaDY<j90  
bStop = true; h.rD}N\L  
} $h9='0Wi0'  
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/5AW?2)  
} #0I{.Wy]  
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/* +,+vkpL-%  
**FileAccess.java WE}kTq
  
*//文件访问(定位，写) Hs"(@eDV&J  
package NetFox; 6TWWlU^e  
import java.io.*; 5/[H+O1;  
u/
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public class FileAccessI implements Serializable{ &WXY'A=  
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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 T&Xl'=/  
RandomAccessFile oSavedFile; wmNHT _  
long nPos; Yw3oJf&  
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public FileAccessI() throws IOException v4Zb? Yb  
{ }g+;y  
this("",0); P47V:E%  
} 3>ex5  
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public FileAccessI(String sName,long nPos) throws IOException @YvO
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{ Gz I~TWc+G  
oSavedFile = new RandomAccessFile(sName,"rw"); vq*Q.0
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this.nPos = nPos; VO3pm
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oSavedFile.seek(nPos); 5F+APz7  
} K`}{0@ilCw  
%
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)CPM7>  
public synchronized int write(byte[] b,int nStart,int nLen) JG`Q;K  
{ <E;pgw!  
int n = -1; seFGJfN\?f  
try{ =-cwXo{Q.O  
oSavedFile.write(b,nStart,nLen); zo{/'BnU  
n = nLen; EqiFy"H  
} O-vGyNxP|  
catch(IOException e) sML=5=otx  
{ =d 2r6%v  
e.printStackTrace (); MfF~8  
} #$~ba%t9%  
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return n; # M,
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} h+.{2^x  
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} 2A`A\19t  
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/* uf<@ruN  
**SiteInfoBean.java <`X"}I3ba  
*/ v!3A9!.  
package NetFox; "eWk#/  
=.<@`1  
WS-dS6Q}  
public class SiteInfoBean { 0|xIBg)  
p?[Tm*r  
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private String sSiteURL; //Site's URL `J<*9dq%  
private String sFilePath; //Saved File's Path XLk<*0tp  
private String sFileName; //Saved File's Name 2I3h MD0  
private int nSplitter; //Count of Splited Downloading File 5S Xn?  
_!;Me )C  
1Q;}zHd  
public SiteInfoBean() U/ V  
{//nSplitter的缺省值为5 {%)s.5Pfw  
//default value of nSplitter is 5 CHd9l]Rbe  
this("","","",5); I3 =#@2  
} X5fmz%VK@  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) M}:=zcZ l  
{ CZnK8&VDY  
sSiteURL= sURL; j hYToMq  
sFilePath = sPath; _LP/!D  
sFileName = sName; X)SDG#&+bF  
this.nSplitter = nSpiltter; 3P~o"a>  
 j1?j6s  
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} Wc3kO'J  
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public String getSSiteURL() r?m+.fJB  
{ j.~!dh$mg  
return sSiteURL; (Q[fS:U  
} 76tdJ!4Z  
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public void setSSiteURL(String value) .Xm(D>>k  
{ ~AYN  
sSiteURL = value; sb:d>6  
} ]3
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r
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public String getSFilePath()  [=O/1T  
{ )}Q(Tl\$  
return sFilePath; "gd=J_Yw  
} ^Jb H?  
HS'Vi9  
tMj;s^P1  
public void setSFilePath(String value) s,bERN7'yO  
{ T +5X0 Nv  
sFilePath = value; `k(yZtb  
} ZnFi<@UB)  
}nt* [:%  
A,i75kd  
public String getSFileName() iu**`WjI\  
{ qQ\Y/}F  
return sFileName; %6Q4yk  
} 3X9b2RY*L/  
T|&[7%F3"  
PFUO8>!pA\  
public void setSFileName(String value) }:: S0l  
{ MT(o"ltQ  
sFileName = value; PcB_oG g  
} f>BWG`  
F4=}}k
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public int getNSplitter() )
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{ Sxjub&=  
return nSplitter; l4T7'U>`  
} FZreP.2)!  
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public void setNSplitter(int nCount) Cs2;z:O]  
{ Uax+dl  
nSplitter = nCount; fEB7j-t  
} (E,T#uc{  
} !+u"3;%h  
.4.b*5  
5cx#SD&5/  
/* }@if6(0  
**Utility.java Qf@I)4
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*/ NM)k/?fA  
package NetFox; +cb6??H  
.ROznCe}  
v}WR+)uFQ  
public class Utility { S9HwIH\m  
}68i[v9Njk  
Nn>'^KZNG  
public Utility() =PGs{?+&O  
{ f#ri'&}c :  
0"~i^  
"~TA SX_?  
} W0I#\b18  
Wg`R_>qQSm  
//线程睡眠 f
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public static void sleep(int nSecond) ;#w3{ NB  
{ V I% 6.6D  
try{ U]a*uF~h  
Thread.sleep(nSecond); RK w$-7O  
} UGK*Gy  
catch(Exception e) %`Z!4L  
{ NnVnUgx  
e.printStackTrace (); (sWLhUgRX  
} G[jW
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} iQ{G(^sZN  
\"hJCP?,  
//日志 A!^q J#  
public static void log(String sMsg) qZ@s#UiB  
{ w3jO6*_ M  
System.err.println(sMsg); yCCrK@{oo  
} r(gXoq_w  
!?Wp+e6  
}@.|?2b +  
public static void log(int sMsg) !A48TgAeE  
{ $1ndKB8)`J  
System.err.println(sMsg); +SJd@y@fR  
} h=-"SW  
} 1;VHM'  
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/* W`^@)|9^)  
**TestMethod.java E!S 78z:  
*/ nS>8bub30  
package NetFox; [$[:"N_  
(XoH,K?{z  
+>JjvYx}\  
public class TestMethod { m.,U:>  
I!^O)4QRx  
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public TestMethod() p,"g+ MwP  
{ ///xx/weblogic60b2_win.exe 6AocmR0D'  
try{ EYA,hc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .bio7c6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1^gl}^|B  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z1"
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fileFetch.start(); X.:]=,aGW  
} $MJm*6h  
catch(Exception e){e.printStackTrace ();} X1~1&:V,<  
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} j&k6O1_  
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public static void main(String[] args) y+7PwBo%e  
{ oY, %Iq  
new TestMethod(); Nz)l<S9>  
} u{L!n$D7  
} <_
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