http断点续传简单实现（java)

/* S+aXlb  
**SiteFileFetch.java f'501MJu  
*/ )nncCUW  
package NetFox; Rs*]I\  
import java.io.*; 4#jW}4C{  
import java.net.*; aPD
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public class SiteFileFetch extends Thread { }.bhs
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SiteInfoBean siteInfoBean = null; //文件信息Bean PL*Mz(&bf  
long[] nStartPos; //开始位置 !kAjne8]d  
long[] nEndPos; //结束位置 E8$k}I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $H}G'LqiG  
long nFileLength; //文件长度 [1Cs  
boolean bFirst = true; //是否第一次取文件 4KH8dau.fF  
boolean bStop = false; //停止标志 .;),e#  
File tmpFile; //文件下载的临时信息 `x
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DataOutputStream output; //输出到文件的输出流 4}C^s\?z  
,|:TML  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `v;9!ReZV  
public SiteFileFetch(SiteInfoBean bean) throws IOException C%#%_
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{ zvJQ@i"Z  
siteInfoBean = bean; `[.b>ztqgJ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %ae|4u#b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ddR*&.Y!a  
if(tmpFile.exists ()) M1UabqQ  
{ b8Bf,&:ys  
bFirst = false; 9@'^}c#  
read_nPos(); (6b*
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} uO=yQ&  
else nd~cpHQR^  
{ .x6c.Y.S  
nStartPos = new long[bean.getNSplitter()]; ,0j7qn@tm  
nEndPos = new long[bean.getNSplitter()]; ^r4@C2#vzJ  
} \PHbJN:BI  
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} ,# i@jB  
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public void run() M`_RkDmy<  
{ Tf0"9  
//获得文件长度 1a_R8j  
//分割文件 D7v-+jypp  
//实例FileSplitterFetch }bkQr)us  
//启动FileSplitterFetch线程 Ii*tux!S  
//等待子线程返回 1W@ C]n4  
try{ k 5~#_D>  
if(bFirst) Q:nBx[%  
{ 0j@nOj(3  
nFileLength = getFileSize(); cJp:0'd  
if(nFileLength == -1) 2kG(\+\  
{ I%
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System.err.println("File Length is not known!"); nYA@t=t0  
} no~Yet+<"  
else if(nFileLength == -2) 6A$ Y]u  
{ jFE1k(2e  
System.err.println("File is not access!"); )uG7 DR  
} y~16o   
else "`va_Mk  
{ F0Nl,9h('  
for(int i=0;i<nStartPos.length;i++) `B1r+uTP~  
{ whoM$  &  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (L{>la!  
} )R~l@QBN  
for(int i=0;i<nEndPos.length-1;i++) =x_~7 Xc{  
{ rzl0*
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nEndPos = nStartPos[i+1]; ]H%SGQPn  
} /y2)<{{I  
nEndPos[nEndPos.length-1] = nFileLength; p'@|Oq&  
} Y! 8 I  
} 3izGMH_`  
utH/E7^8  
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//启动子线程 seNJ6p=`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @^O+ulLJ,]  
for(int i=0;i<nStartPos.length;i++) }KEL{VUX  
{ j@ehcK9|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `<cnb!]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vOF"p4 ^3  
nStartPos,nEndPos,i); d9qA\ [  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a;GuFnfn,  
fileSplitterFetch.start(); VM.4w.})_E  
} T(@J]Y-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w# iezo. 0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J>o%6D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :"ta#g'  
nEndPos = " + nFileLength); %I`%N2ss  
// fileSplitterFetch[nPos.length-1].start(); ?QbxC,& i  
AlVBhR`  
@N(*1,s2  
//等待子线程结束 #8{U0 7]"  
//int count = 0; [9-&Lq_ g  
//是否结束while循环 w$`[C+L  
boolean breakWhile = false; ],?$&  
@7}
]\}SR  
[?QU'[  
while(!bStop) b235Zm  
{ REK(^1 h  
write_nPos(); hxT{!g  
Utility.sleep(500); Hv3<gyD  
breakWhile = true; QDHTP|2e  
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for(int i=0;i<nStartPos.length;i++) sMZ90Q$  
{ +N3f{-{"Yo  
if(!fileSplitterFetch.bDownOver) X~o6Xkg  
{ zJMm=Mw^  
breakWhile = false; >QA;02  
break; =sIkA)"!=  
} A.8[FkiNmD  
} 8AGP*"gI  
if(breakWhile) Y|3n^%I  
break; w4<n=k  
>Q-"-X1  
]b+Nsr~  
//count++; Szb#:C  
//if(count>4) h!zev~u1)`  
// siteStop(); grs~<n|o\  
} CGp7 Tx#  
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T {![a{  
System.err.println("文件下载结束！"); ^U8^P]{R|  
} Mhwuh`v%  
catch(Exception e){e.printStackTrace ();} z,f  
} wk@S+Q  
23iMG]J&  
q+J;^u"E  
//获得文件长度 JtbwY@R  
public long getFileSize() <rbzsn"a  
{ zF7*T?3b"  
int nFileLength = -1; k^i\<@v  
try{ YqEB%Y~N+  
URL url = new URL(siteInfoBean.getSSiteURL()); R2Y.s^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C25EIIdRb  
httpConnection.setRequestProperty("User-Agent","NetFox"); vMHJgpd&j  
sI OT6L^7  
{;2Gl$\r  
int responseCode=httpConnection.getResponseCode(); D=^|6}  
if(responseCode>=400) i^Ip+J+[  
{ P2t9RCH  
processErrorCode(responseCode); )J>-;EYb8  
return -2; //-2 represent access is error "BvAiT
{u  
} 2zlBrjk;  
i2yE-sgF  
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String sHeader; `JZ`j7f  
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for(int i=1;;i++) U(~d^9/#  
{ +>BD^[^^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); MRb6O
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//Utility.log(in.readLine()); h3YWqSj  
sHeader=httpConnection.getHeaderFieldKey(i); wj$WE3Y  
if(sHeader!=null) 4COo~d  
{ hVl^vw7o  
if(sHeader.equals("Content-Length")) gc[BP>tl\  
{ =}xH6^It  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); tXg>R _\C  
break; L Rn)  
} p3
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} CYHo~VIK  
else g54b}vzm  
break; y yqya[-11  
} H]<@\g*l@P  
} >J['so2Bf  
catch(IOException e){e.printStackTrace ();} RK\$>KFE  
catch(Exception e){e.printStackTrace ();} nN*:"F/^  
av:9kPKm  
}}q_QD_  
Utility.log(nFileLength); Xt$o$V  
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t  
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return nFileLength; hTS?+l  
} 1b
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[R%Pf/[Fr  
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//保存下载信息（文件指针位置） SLi?E  
private void write_nPos() .DN)ck:e;  
{ 3j}@}2D  
try{ J5j3#2l  
output = new DataOutputStream(new FileOutputStream(tmpFile)); nm{J  
output.writeInt(nStartPos.length); w\{o
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for(int i=0;i<nStartPos.length;i++) 56l1&hp8In  
{ haoQr)S  
// output.writeLong(nPos); [[A}MF*@  
output.writeLong(fileSplitterFetch.nStartPos); '^ob3N/Y [  
output.writeLong(fileSplitterFetch.nEndPos); xL#UMvZ>;h  
} @";zM&  
output.close(); upefjwm  
} 7:P+S%ZL  
catch(IOException e){e.printStackTrace ();} qf?X:9Wt  
catch(Exception e){e.printStackTrace ();} ;%V)lP"o  
} E%np-is{1  
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//读取保存的下载信息（文件指针位置） 7>$&CWI  
private void read_nPos() :@c\a99Kx  
{ *L+)R*|:&  
try{  WgayH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xwe^_7  
int nCount = input.readInt(); b.lK0 Xo  
nStartPos = new long[nCount]; )2dTgvy  
nEndPos = new long[nCount]; oJln"-M1nx  
for(int i=0;i<nStartPos.length;i++) WJs2d73Qp  
{ 72akOx   
nStartPos = input.readLong(); J<27w3bs~p  
nEndPos = input.readLong(); }N`m7PSf  
} 6ntduXeNVh  
input.close(); ]zUvs6ksLG  
} TBr@F|RXiO  
catch(IOException e){e.printStackTrace ();} d"~-D;  
catch(Exception e){e.printStackTrace ();} p)y'a+|7  
} -V'h>K  
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private void processErrorCode(int nErrorCode) ?o883!&v  
{ vC|V8ea  
System.err.println("Error Code : " + nErrorCode); us$=)m~v+  
} 's7 (^1hH  
{6Qd,CX
 
! 1wf/C;=  
//停止文件下载 I]vCra  
public void siteStop() (n
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{ hY[Vs5v  
bStop = true; :W*']8 M-  
for(int i=0;i<nStartPos.length;i++) R0DWjN$j  
fileSplitterFetch.splitterStop(); 'A)r)z{X  
w\(;>e@  
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} x!^u$5c  
} CTh!|mG  
//负责部分文件的抓取 u~\I  
**FileSplitterFetch.java s$PPJJT{b  
*/ +L
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package NetFox; WB(Gx_o3  
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import java.io.*; "79"SSfOc  
import java.net.*; ML-?#jNa<  
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public class FileSplitterFetch extends Thread { wD|I^y;  
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{(j1#9+9  
String sURL; //File URL ,[{Z_co  
long nStartPos; //File Snippet Start Position FdFN4{<QZ  
long nEndPos; //File Snippet End Position |xX>AMZc)D  
int nThreadID; //Thread's ID 3Sh#7"K3  
boolean bDownOver = false; //Downing is over aZBb@~
Y  
boolean bStop = false; //Stop identical 4b<>gpQ  
FileAccessI fileAccessI = null; //File Access interface o|O|e9m(  
,'c?^ $J|z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [
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{ -ttH{SslM  
this.sURL = sURL; 9:1[4o)~  
this.nStartPos = nStart; ~ u',Way  
this.nEndPos = nEnd; Tn"/EO^N  
nThreadID = id; T2p;#)dP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }[c,/NH  
} zd-qQ.j0  
(yxHXO9N  
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public void run() \\{+t<?J  
{ RZr
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while(nStartPos < nEndPos && !bStop) Y24H` s1u/  
{ OS7^S1r-  
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try{ q{E44 eQ7F  
URL url = new URL(sURL); &|&tPD/dJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T=D|jt  
httpConnection.setRequestProperty("User-Agent","NetFox"); wOU\&u|
 
String sProperty = "bytes="+nStartPos+"-"; fOtzbYVC  
httpConnection.setRequestProperty("RANGE",sProperty); # @~HpqqR  
Utility.log(sProperty); qr|v|Ejd~  
@kmOz(  
KCc7u8   
InputStream input = httpConnection.getInputStream(); @M_p3[c\  
//logResponseHead(httpConnection); "CcdwWM  
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byte[] b = new byte[1024]; ~;uc@GGo  
int nRead; m2h@*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *%;+3SV  
{ RwyRPc_  
nStartPos += fileAccessI.write(b,0,nRead); l:$i}
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//if(nThreadID == 1) TOC2[mc'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E Zh.*u@^r  
} #
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Utility.log("Thread " + nThreadID + " is over!"); m.EIMuj  
bDownOver = true; dw"{inMf  
//nPos = fileAccessI.write (b,0,nRead); rwh,RI) )g  
} 2n|]&D3V"'  
catch(Exception e){e.printStackTrace ();} r>Rm=eKJ  
} v"3($?au0  
} Rt=zqfJ  
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Ap)[;_9BD  
//打印回应的头信息 f9FEH7S68  
public void logResponseHead(HttpURLConnection con) Fh0cOp(  
{ YOE!+MiO  
for(int i=1;;i++) GX-V|hLaGX  
{ oTLA&dy@  
String header=con.getHeaderFieldKey(i); .m/$ku{/J  
if(header!=null) `j)S7KN  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;2\+O"}4H  
Utility.log(header+" : "+con.getHeaderField(header)); /.m&rS  
else 6! .nj3$*  
break; HJ^SqSm  
} yNU.<d 5  
} i$CN{c*  
7>,(QHl
 
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public void splitterStop() uzgQ_  
{ JDp{d c  
bStop = true; pB0p?D)n  
} O~~
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} vv0+F6 @  
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/* Md[M}d8
 
**FileAccess.java jqv"8S5  
*//文件访问(定位，写) CaE1h9  
package NetFox; RJhafUJ zH  
import java.io.*; OPe3p {]  
)oAxt70  
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=  
public class FileAccessI implements Serializable{ Q!*}^W  
|S0nR<x-M  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1~aP)q  
RandomAccessFile oSavedFile; o4PJ9x5R!  
long nPos; ~4^~w#R  
%pG^8Q()   
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public FileAccessI() throws IOException (2uF<$7(  
{ z}z 6Vg  
this("",0); T0TgV  
} orON)Sks  
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public FileAccessI(String sName,long nPos) throws IOException CyXFuk!R  
{ 'nRoa7v(  
oSavedFile = new RandomAccessFile(sName,"rw"); 0*^>/*  
this.nPos = nPos; EJ@&vuDd$  
oSavedFile.seek(nPos); J1UG},-h  
} 50jZu'z:  
)Gm,%[?2C  
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public synchronized int write(byte[] b,int nStart,int nLen) rHaj~s 4  
{ )sZJH9[K  
int n = -1; !%X#;{  
try{ :tf'Gw6v  
oSavedFile.write(b,nStart,nLen); 6m$lK%P{1  
n = nLen; MP_LdJM1E  
} [L ?^+p>  
catch(IOException e) {16]8-pe  
{ R(AS$<p{!>  
e.printStackTrace (); 6Q*Zy[=  
} *YO^+]nmY  
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return n; QCAoL.v  
} aDZ,9}  
@i <vlHpl  
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} Ek6z[G` O  
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/* E^4}l2m_  
**SiteInfoBean.java O;lGh1.  
*/ WRov7  
package NetFox; [jEZ5]%  
iu.v8I;<  
s3sPj2e{  
public class SiteInfoBean { / DG t  
8vqx}2  
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private String sSiteURL; //Site's URL ? FlQ\q  
private String sFilePath; //Saved File's Path S7 !;Z@  
private String sFileName; //Saved File's Name NH'Dz6K5  
private int nSplitter; //Count of Splited Downloading File zvbO q  
H@!]5 <:9  
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public SiteInfoBean() WCD)yTg:ES  
{//nSplitter的缺省值为5 ZA+w7S
3  
//default value of nSplitter is 5 ^).  
this("","","",5); K1$
   
} F}~qTF;H  
vzFo"  
0,whTnH|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) dym K@  
{ Ji4JP0  
sSiteURL= sURL; 8I[=iU7]l  
sFilePath = sPath; Ef$a&*)PH  
sFileName = sName; FDal;T  
this.nSplitter = nSpiltter; M;LR$'cP  
@1N.;]|  
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} mg]t)+PQ  
i_(6}Y&  
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public String getSSiteURL() H
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{ N 9W,p2  
return sSiteURL; fSVb.MZa7  
} _9C,N2a{C  
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public void setSSiteURL(String value) 1
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{ }qT{" *SC  
sSiteURL = value; [vqf hpz  
} ;ObrBN,Fu  
F0kdwN4;  
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public String getSFilePath() ]P/i}R:  
{ #>M^BOR8  
return sFilePath; xzHb+1+p  
} Ae\:{[c_D  
x[=,$;o+  
3Cgv($xl&  
public void setSFilePath(String value) A0,h7<i  
{ a<J<Oc!  
sFilePath = value; ]nNn"_qh  
} 21O@yNpS$  
V:/v r  
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public String getSFileName() I? ="Er[g}  
{ iG#92e4  
return sFileName; ,FwpHs $A  
} M`n0 qy  
}kG>6_p?  
Rl&nR$#  
public void setSFileName(String value) w3;{z ,,T  
{ tA]u=-_h  
sFileName = value; T+q5~~\d  
} %l?*w~x  
*zQhTYY  
h=Q2 ?O8  
public int getNSplitter() VTU(C&"S  
{ eA
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return nSplitter; fA"c9(>m%]  
} k
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public void setNSplitter(int nCount) ;d<O/y,:4  
{ 5=\^DeM@ H  
nSplitter = nCount; KZO[>qC"R  
} eLLOE)x  
} Fi/`3A@68  
:}2Tof2  
hBaF^AWW  
/* j\"d/{7Q  
**Utility.java Lr9E02  
*/ j
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package NetFox; \x:} |   
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public class Utility { fw VI%0C@  
"!_vQ^y  
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public Utility() BNe>Lko  
{ ~^'WHuzPy  
?gBFfi  
^q`RaX)  
} /;vHAtt;f  
-BSO$'{7  
//线程睡眠 b6xz\zCL  
public static void sleep(int nSecond) )3R5cq  
{ M)U)Sc zHO  
try{ J\>/J%  
Thread.sleep(nSecond); AQ0zsy  
} =J"c'Z>.  
catch(Exception e) aK_k'4YTm  
{ }u1h6rd `  
e.printStackTrace (); dd6%3L{cn  
} \%B7M]P  
} tt CC] Q  
8)MWC:  
//日志 VoQhzp6&  
public static void log(String sMsg) {6%-/$LX  
{ scTt53v^  
System.err.println(sMsg); kGL3*x  
} 'MW O3  
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public static void log(int sMsg) 2R ^6L@fw  
{ _0ZU I^#  
System.err.println(sMsg); _T7XCXEk   
} }346
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} Bz|/TV?X(  
 3bJ|L3G  
ktRGl>J  
/* *yY\d.6(  
**TestMethod.java GZHJ4|DK  
*/ u%6b|M@P  
package NetFox; aK]AhOG  
sl"H!cwF  
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public class TestMethod { [>U2!4=$M  
pe>?m^gz[  
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public TestMethod() 2kk; z0f  
{ ///xx/weblogic60b2_win.exe OOXP1L  
try{ (Q&O'ng1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @6%7X7m  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }$sTnea  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ck>]+rl  
fileFetch.start(); #3{{[i(;i  
} 4#.Q|vyl]"  
catch(Exception e){e.printStackTrace ();} mg>wv[ 7  
P!IXcPKW53  
2aX{r/Lc  
} sl(go^  
yhI;FNSf  
]rNxvFN*j  
public static void main(String[] args) xn@oNKD0  
{ g>#}(u!PH  
new TestMethod(); | +uc;[`  
} th<>%e}5c  
} HV7f%U  
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