http断点续传简单实现（java)

/* 2T(+VeM
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**SiteFileFetch.java p"jze3mF  
*/ I 2OQ
  
package NetFox; wWf_d jd  
import java.io.*; T!41[vm(  
import java.net.*; f##/-NG  
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public class SiteFileFetch extends Thread {  #$2
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} d8\ Jg  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &hL2xx=  
long[] nStartPos; //开始位置 (^g XO  
long[] nEndPos; //结束位置 A! HJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 bE2O[B  
long nFileLength; //文件长度 OA\]|2 :  
boolean bFirst = true; //是否第一次取文件 m||9,z-  
boolean bStop = false; //停止标志 %+|sbRBb  
File tmpFile; //文件下载的临时信息 QE)zH)(  
DataOutputStream output; //输出到文件的输出流 I''n1v?N  
3)?WSOsL:  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |V{ Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException vp!F6ZwO  
{ +'olC^?5 }  
siteInfoBean = bean; )YAU|sCAi$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h2Th)&Fb>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &^HVuYa.0  
if(tmpFile.exists ()) 0
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{ (&v|,.c^)1  
bFirst = false; ly6zz|c5  
read_nPos(); <BZC5b6  
} kMnG1K  
else LJ@r+|>  
{ Qf~$9?z  
nStartPos = new long[bean.getNSplitter()]; q%$p56\?3  
nEndPos = new long[bean.getNSplitter()]; E7@Gpu,o  
} ~UO}PI`C  
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} yOKzw~;0%  
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public void run() G?XA",AC  
{ Mb\(52`)Q  
//获得文件长度 ,>kVVp
u  
//分割文件 Ng W"wh  
//实例FileSplitterFetch ty[p5%L1  
//启动FileSplitterFetch线程 iZeq l1O  
//等待子线程返回 V!^0E.?a  
try{ dc1Zh W4  
if(bFirst) vo*oCfm  
{ c6c@XdV  
nFileLength = getFileSize(); o}/|"(K  
if(nFileLength == -1) VR&dy|5BO  
{ &V<f;PF(I  
System.err.println("File Length is not known!"); 3rMJC\h  
} Kn@#5MC rU  
else if(nFileLength == -2) 2=
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{ Q25VG5G  
System.err.println("File is not access!"); u)o-H!a  
} QQV8Vlv"  
else =MJB:  
{ ~XuV:K3  
for(int i=0;i<nStartPos.length;i++) e_KfnPY   
{ M_ %-A  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Khc^q*|C)  
} gVzIEE25  
for(int i=0;i<nEndPos.length-1;i++) `t)9u^[<(  
{ y'4Qt.1ukN  
nEndPos = nStartPos[i+1]; Q/0gd? U?  
} nC%qdzT  
nEndPos[nEndPos.length-1] = nFileLength; C<(oaeQY  
} Fih pp<  
} Ow4(1eE_  
Gvh"3|u?z  
/PTRe5-7  
//启动子线程 W9tZX5V1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Mkk.8AjC|  
for(int i=0;i<nStartPos.length;i++) _[Imwu}  
{ m=^]93+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $,, PF/N8c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F
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nStartPos,nEndPos,i); ; xp-MK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >|kD(}Axf  
fileSplitterFetch.start(); zN[& iKf  
} 457{9k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 81s }4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); YT(Eh3ID  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", C]5 kQ1Og  
nEndPos = " + nFileLength); kV?fie<\)  
// fileSplitterFetch[nPos.length-1].start(); Bz-jy.  
v=lW5%r,'  
!1=OaOT  
//等待子线程结束 !f5
2JQyh  
//int count = 0; 2 Kjd!~Z$  
//是否结束while循环 7G-?^  
boolean breakWhile = false; `{Q'iydU  
bK~Toz<k  
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while(!bStop) &U|c=$!\  
{ !vRZh('R  
write_nPos(); b-  t  
Utility.sleep(500); f?k0(rl  
breakWhile = true; h L [eA  
sV%DX5@  
-#;xfJE  
for(int i=0;i<nStartPos.length;i++) Z*mbhod  
{ !.mR]El{K  
if(!fileSplitterFetch.bDownOver) 4l%W]'  
{ V27RK-.N!  
breakWhile = false; S}%z0g<  
break; -~~h1  
} +@3+WD  
} si6CWsb_f  
if(breakWhile) yFDeYPZP  
break; Z)E)-2U$@  
Gg9MAK\C9  
=cjO]  
//count++; ]Rxo}A  
//if(count>4) vFR*3$R  
// siteStop(); 9N9&y^SmD  
} |3,WiK='  
IV. })8
 
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System.err.println("文件下载结束！"); 9_:"`)]3B  
} r@zT!.sc!  
catch(Exception e){e.printStackTrace ();} (wZ!OLY%}  
} 5qQMGN$K  
4mo/MK&M:  
0N>K4ho6{  
//获得文件长度 zQY ,}a  
public long getFileSize() 1;=L] L?  
{ ; o_0~l=-/  
int nFileLength = -1; C-c'"F
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try{ P
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URL url = new URL(siteInfoBean.getSSiteURL()); {j>a_]dTVX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BM /FOY;  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8Zsaq1S  
<5z!0m-G  
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int responseCode=httpConnection.getResponseCode(); t7F0[E'=5\  
if(responseCode>=400) +X^GS^mz  
{ W$zRUG-  
processErrorCode(responseCode); xo'!$a}I2  
return -2; //-2 represent access is error |@JTSz*Or  
} x0Loid\f  
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String sHeader; @L!^2v  
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;(`bP  
for(int i=1;;i++) xE<H@@w  
{ ~-7/9$ay5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ex p?x  
//Utility.log(in.readLine()); {\1b
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sHeader=httpConnection.getHeaderFieldKey(i); hTn"/|_SW  
if(sHeader!=null) jerU[3  
{ Y%"$v0D  
if(sHeader.equals("Content-Length")) > U?\WgE$  
{ )9
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6J,h}S  
break; apa&'%7  
} :Pdh##k  
} I8J>>H'#A  
else H;nzo3x  
break; Zwc&4:5%  
} ?;W"=I*3  
} ~3:hed7:  
catch(IOException e){e.printStackTrace ();} YTefEG]|q  
catch(Exception e){e.printStackTrace ();} # `E  
C
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Utility.log(nFileLength); :P_h_Tizv  
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return nFileLength; jD S\  
} iw,u
wh|L  
G^)]FwTs  
a^J(TW/  
//保存下载信息（文件指针位置） ]C,j80+pK  
private void write_nPos() %;QK5L 
 
{ Hl8-q!  
try{ '/HShS!d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); L1RD`qXu.  
output.writeInt(nStartPos.length); WS n>P7sY  
for(int i=0;i<nStartPos.length;i++) 1iz =i^}  
{ ^aAs=KditO  
// output.writeLong(nPos); {"Sv~L|J;  
output.writeLong(fileSplitterFetch.nStartPos); \UK}
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output.writeLong(fileSplitterFetch.nEndPos); 5\
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} Ro2V-6/  
output.close(); PM84Z@Y  
} Jl\xE`-7  
catch(IOException e){e.printStackTrace ();} X2Ak  
catch(Exception e){e.printStackTrace ();} Fw&ImRMk  
} PdO"e  
jV*10kM<  
[IOI&`?D  
//读取保存的下载信息（文件指针位置） y{mt *VA4  
private void read_nPos() e x Z/  
{ GqCBD-@4v.  
try{ tjtvO@?1-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); q$
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int nCount = input.readInt(); 3'.3RKV  
nStartPos = new long[nCount]; =_k  
nEndPos = new long[nCount]; 8wkhbD|;  
for(int i=0;i<nStartPos.length;i++) r[Pp[g-J  
{ 3\m!  
nStartPos = input.readLong(); Lld45Bayb  
nEndPos = input.readLong(); ~>>_`;B  
} y p{Dl  
input.close(); }>@SyE'Q  
} 4Y59^  
catch(IOException e){e.printStackTrace ();} g$GGo[_0  
catch(Exception e){e.printStackTrace ();} :} =lE"2  
} O/#3QK  
9~~NxWY%x  
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private void processErrorCode(int nErrorCode) L-?ty@-i  
{ x*z&#[(0g!  
System.err.println("Error Code : " + nErrorCode); Jt]RU+TB  
} bQ3<>e\%B  
e: Sd#H!  
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//停止文件下载 xwD`R*  
public void siteStop() ir.RO7f  
{ cL#-vW<s3  
bStop = true; &l2xh~L  
for(int i=0;i<nStartPos.length;i++) ?X|q   
fileSplitterFetch.splitterStop(); {ax]t-ZwJ5  
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9RlJf=Z#H  
} afX|R  
}
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//负责部分文件的抓取 [(*Eg!?W
=  
**FileSplitterFetch.java Y(6evo&IR  
*/ E}9wzPs  
package NetFox; mF@7;dpr  
hA 5p'a+K  
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import java.io.*; Y({ R\W|  
import java.net.*; %( 7##f_  
9oc_*V0<  
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public class FileSplitterFetch extends Thread { L3\#ufytb  
ZbT$f^o}M]  
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String sURL; //File URL h'em?fN(  
long nStartPos; //File Snippet Start Position ')q4d0B`"  
long nEndPos; //File Snippet End Position JqO1 a?H  
int nThreadID; //Thread's ID I;JV-jDM  
boolean bDownOver = false; //Downing is over i;{lY1  
boolean bStop = false; //Stop identical '/qy_7O  
FileAccessI fileAccessI = null; //File Access interface d%k7n+ICQ4  
\}h  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A3tv'-e9  
{ yC$m(Y12FN  
this.sURL = sURL; QSF0?Puf  
this.nStartPos = nStart; rtAPkXJFM  
this.nEndPos = nEnd; >(P(!^[f  
nThreadID = id; lv/
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 l9uocP:D  
} 3 orZBT  
I]d-WTd  
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public void run()  b}NNkM  
{ TOG4=y-N  
while(nStartPos < nEndPos && !bStop) bj@sci(1?  
{ ^X{U7?x  
`>UUdv{C  
>z%YKdq  
try{ }I uqB*g[t  
URL url = new URL(sURL); }&/>v' G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n
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httpConnection.setRequestProperty("User-Agent","NetFox"); :y7K3:d3  
String sProperty = "bytes="+nStartPos+"-"; P9 HKev?y  
httpConnection.setRequestProperty("RANGE",sProperty); :qxWANUa  
Utility.log(sProperty); IH=$ wc  
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V/H+9+B7Im  
InputStream input = httpConnection.getInputStream(); 2F*>&n&Db7  
//logResponseHead(httpConnection); N{bg-%s10i  
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byte[] b = new byte[1024]; <o|fH~?X  
int nRead; c6 &k?Puy  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <v
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{ v3cMPN  
nStartPos += fileAccessI.write(b,0,nRead); KwHN c\\  
//if(nThreadID == 1) kCD]&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #&)H&H}  
} "{vWdY|"  
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Utility.log("Thread " + nThreadID + " is over!"); v)*MgfS  
bDownOver = true; =&08s(A  
//nPos = fileAccessI.write (b,0,nRead); 4>oM5Yf8  
} Mm*V;ADF  
catch(Exception e){e.printStackTrace ();} OWrQKd  
} y'`7zJ  
} RiAg:  
rfVQX<95=/  
,gZp/yJ;  
//打印回应的头信息 'gor*-o:wu  
public void logResponseHead(HttpURLConnection con) Kd 1=mC  
{ 3'x>$5W  
for(int i=1;;i++) v@Eb[7Kq/1  
{ PcA^ jBgGl  
String header=con.getHeaderFieldKey(i); &'i_A%V  
if(header!=null) bL* b>R[x  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Gr\jjf`  
Utility.log(header+" : "+con.getHeaderField(header)); [;IEZ/ZX  
else L&s~j/pR  
break; {1Cnrjw  
} 0J/yd  
} V0{#q/q  
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public void splitterStop() m-4#s  
{ kOo  Vqu  
bStop = true; T8\@CV!  
} mK$E&,OkA  
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} y "+'4:_  
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/* nI?*[y
}  
**FileAccess.java @d{}M)6\!
 
*//文件访问(定位，写)
*LhwIY  
package NetFox; 1Q FsT  
import java.io.*; Q8Ek}O\MC  
5@1h^wv  
+|bmUm<2  
public class FileAccessI implements Serializable{ `^{G`es  
5'f_~>1Wt  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 H0inU+Ih  
RandomAccessFile oSavedFile; pD[&,gV$  
long nPos; (BtU\f#d  
1J1Jp|j.  
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public FileAccessI() throws IOException XGR63hXND  
{ K
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this("",0);  ,d/$!Yf  
} {@L{l1|0  
I`XOvSO  
-"ZNkC=
 
public FileAccessI(String sName,long nPos) throws IOException V^FM-bg%9  
{ )G/
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oSavedFile = new RandomAccessFile(sName,"rw"); ESoqmCJjb:  
this.nPos = nPos; i#YDdz  
oSavedFile.seek(nPos); <H]PP6_g:  
} ;DX{+Z[  
Q(N'Oj:J  
;p*L(8<YI  
public synchronized int write(byte[] b,int nStart,int nLen) @=w)a  
{ {(-923|,  
int n = -1; z^gz kXx7  
try{ j,].88H  
oSavedFile.write(b,nStart,nLen); %LC)sSq{H  
n = nLen; 4N=,9  
} _5n2'\] H`  
catch(IOException e) FEhBhv|m  
{ rMWvW(@@D  
e.printStackTrace (); o/
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} b?0WA.[{  
J6EzD\.Y)  
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return n; `m1stK(PO  
} {=I,+[(  
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} 1c"s+k]9  
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/* 
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**SiteInfoBean.java @.cord`  
*/ 6C.!+km  
package NetFox; P[H`]q|  
n}Thc6f3D  
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public class SiteInfoBean { #|769=1  
ZHA&gdK@  
3<FqK\P  
private String sSiteURL; //Site's URL H"
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private String sFilePath; //Saved File's Path
}T902RL0  
private String sFileName; //Saved File's Name FLPN#1  
private int nSplitter; //Count of Splited Downloading File Th,]nVsGs~  
E.$//P n|1  
@:hWahMy  
public SiteInfoBean() W{ozZuo  
{//nSplitter的缺省值为5 AS0(NlV  
//default value of nSplitter is 5 .wm<l:  
this("","","",5); ZPM7R3%V)z  
} WR.7%U';  
X+emJ&Z$@  
'%Oo1:wJ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $
?: -A  
{ RToX[R;1E  
sSiteURL= sURL; 0=`aXb-  
sFilePath = sPath; \iEJ9V  
sFileName = sName; ZKI` ;  
this.nSplitter = nSpiltter; Ca"i<[8  
!Y^$rF-+  
tvzO)&)$  
} _jkJw2+s\  
v/KTEM  

B7{j$0fm*  
public String getSSiteURL() ,V4pFQzL  
{ aM[fag$c  
return sSiteURL; &U.y):  
} H-5f!>)  
Rx%kAt2X  
&#q%#M:  
public void setSSiteURL(String value) ~|KMxY(:  
{ ?aG~E  
sSiteURL = value; d9D*w/clMi  
} #2.C$  
5hCfi  
^kB9 I8u  
public String getSFilePath() 0Z%<H\Z  
{ S!}pL8OE
 
return sFilePath; T?
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} ~;I{d7z,;  
mOjl0n[To]  
-IV-"-6(  
public void setSFilePath(String value) AQ.q?'vE)  
{ 0XIrEwm@%  
sFilePath = value; gA
i}"};  
} r:^`005  
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QQ,w:OjA0  
public String getSFileName() A@k=Mk  
{ >W8PLo+i  
return sFileName; oDA'}[/  
} JR_c]AQYu  
L?y,xA_  
 [7)#3  
public void setSFileName(String value) zgpPu4t  
{  -gS/  
sFileName = value; ]}0+7Q  
} / dn]`Ge)  
p:U{3uN 62  
3^&pb  
public int getNSplitter() t;ga>^NA"  
{ s{j3F  
return nSplitter; p7O4CP>9[  
} p/s5[>N  
CV7.hF<  
z!j`Qoh?V9  
public void setNSplitter(int nCount) WHF:>0B  
{ 2
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nSplitter = nCount; ]gj@r[  
} 0$49
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} b}G +7B  
]7"mt2Q=3  
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/* BQ&h&57K  
**Utility.java /L[:C=u  
*/ }`^<ZNkb/  
package NetFox; `}Hnj*  
1$2Rs-J  
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public class Utility { `Op
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%s)E}cGH  

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public Utility() IWpUbD|kC  
{ ^jhHaN]G^  
7y`
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2W~2Hk=0+%  
} TT&!WbA-Hk  
o_$r*Z|HG  
//线程睡眠 Ap>n4~  
public static void sleep(int nSecond) !!K=v7M  
{ ,|c_l)  
try{ \S2'3SDd/  
Thread.sleep(nSecond); Wj*6}N/  
} )d1,}o  
catch(Exception e) T@HozZ  
{ #QDV_ziE5  
e.printStackTrace (); XJ NKM~
 
} CC87<>V  
} 1Q;`<=  
)DLK<10  
//日志 ZmHl~MR@  
public static void log(String sMsg) *AN#D?X
_  
{ |m EJJg`"7  
System.err.println(sMsg); %yrP: fg/  
} g%[Ruugu  
IH0^*f  
9VY_gi=vL  
public static void log(int sMsg) ohyUvxvj  
{ p]g/iLDZ  
System.err.println(sMsg); 2I4P":q  
} q B2#EsZ  
} 1Q$ M/}  
xX>448=  

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/* 4'8.f5  
**TestMethod.java / q!&I  
*/ aH#|Lrd
J  
package NetFox; nBj7Q!lW  
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4%{m7CK}  
public class TestMethod { \%VoX`B  
_0`O}  
.lnD]Q  
public TestMethod() O&0R ~<n  
{ ///xx/weblogic60b2_win.exe [(K^x?\Y0'  
try{ Ywr{/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,J#5Y.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); x[kdQj2[&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); zC^Ib&gm>,  
fileFetch.start(); g/yXPzLU  
} cK } Qu  
catch(Exception e){e.printStackTrace ();} D.GSl  
u!S{[7 FY  
A|+{x4s`  
} I|:j~EY  
^eRuj)$5A  
WveFB%@`;  
public static void main(String[] args) 1,J.  
{ x@ O:  
new TestMethod(); $b$D[4  
} }R x%&29&  
} {%Y7]*D  
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