http断点续传简单实现（java)

/* =YOq0  
**SiteFileFetch.java ;y/&p d+  
*/ cY0NQKUk~  
package NetFox; VMXccT9i!  
import java.io.*; b<n*wH  
import java.net.*; jH({Qc,97  
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public class SiteFileFetch extends Thread { F}wy7s2i  
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SiteInfoBean siteInfoBean = null; //文件信息Bean d)1 d0ES  
long[] nStartPos; //开始位置 SFv'qDA  
long[] nEndPos; //结束位置 3f@@|vZF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -U.>K,M  
long nFileLength; //文件长度 9sJ=Nldq  
boolean bFirst = true; //是否第一次取文件 TkBHlTa"=  
boolean bStop = false; //停止标志 gNUYHNzDM(  
File tmpFile; //文件下载的临时信息 u%!/-&?wF  
DataOutputStream output; //输出到文件的输出流 ose(#n40  
nm Y_)s  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） nl5A{ s
 
public SiteFileFetch(SiteInfoBean bean) throws IOException aS=-9P;v  
{ < KGq  
siteInfoBean = bean; JuQwZ]3ed  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _wH>h$E  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); VkdGGY  
if(tmpFile.exists ()) 1-0tG+  
{ /W9(}Id6  
bFirst = false; ' Dcj\=8
 
read_nPos(); >mJH@,F:  
} y)vK=,"  
else /#jH#f[  
{ )0+6^[Tqq  
nStartPos = new long[bean.getNSplitter()]; 0Q?)?8_  
nEndPos = new long[bean.getNSplitter()]; `%;Hj _X}  
} KW-GVe%8f  
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' Dp;fEU$  
} o=J-Ju
 
% bfe_k(  
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public void run() 'b)qP|  
{ _NefzZWUJ  
//获得文件长度 :aQ.:b(n  
//分割文件 mC2K &'[  
//实例FileSplitterFetch ~(nc<M[  
//启动FileSplitterFetch线程 76H>ST@G|  
//等待子线程返回 7-:R{&3Lm:  
try{ l^F ?^kP  
if(bFirst) (Zg'])  
{ 50_[n$tqE  
nFileLength = getFileSize(); xt_:R~/[  
if(nFileLength == -1) {Y-~7@  
{ 0FSNIPx  
System.err.println("File Length is not known!"); A]Bf&+V  
} Jvc:)I1NE7  
else if(nFileLength == -2) mww<Xm'  
{ vAp<Muj(a  
System.err.println("File is not access!"); <qg4Rz\c]  
} n,U?]mr  
else ZDg(D"  
{ IjGPiC  
for(int i=0;i<nStartPos.length;i++) ?4A/?Z]ub  
{ H-vHcqFx3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); B (Ps/  
} cbN;Kv?ak}  
for(int i=0;i<nEndPos.length-1;i++) *Nm$b+  
{ a`L:E'
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nEndPos = nStartPos[i+1]; o]EL=j  
} c {/J.  
nEndPos[nEndPos.length-1] = nFileLength; > vdmN]  
} ]{oZn5F  
} gk6UV2nE?  
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//启动子线程 fuzB;Ea  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Z
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for(int i=0;i<nStartPos.length;i++) N_IKH)  
{ Cb1w8l0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LH)XD[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I)tiXcJw  
nStartPos,nEndPos,i); ]?pQu'-(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~:{05W  
fileSplitterFetch.start(); M@#T`aS  
} 9.8%Iw  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4qdoF_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); XEQTTD<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;-6-DEL  
nEndPos = " + nFileLength); |GtvgvO,  
// fileSplitterFetch[nPos.length-1].start(); V(_1q  
B*N1)J\5  
(J[Xryub  
//等待子线程结束 lDTHK2f  
//int count = 0; -QroT`gy  
//是否结束while循环 ,Cb3R|L8  
boolean breakWhile = false; 12a`,~  
yL*]_  
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while(!bStop) ,$0-I@*V  
{ @(Y!$><Is  
write_nPos(); 6$6QAW0+f  
Utility.sleep(500); ;eN ^'/4A  
breakWhile = true; pZ&,YX  
&'SD1m1P  
4b:|>Z-  
for(int i=0;i<nStartPos.length;i++) PVsKI<  
{ #,%7tXOLR  
if(!fileSplitterFetch.bDownOver) 7 !$[XD  
{ s{-gsSmE  
breakWhile = false; n:,mo}?X  
break; e"ehH#i  
} OvtE)ul@  
} DMM<,1  
if(breakWhile) f<NR6],}  
break; f#=c=e-A  
P.}d@qD{)  
?@ F2Kv  
//count++; 3''Sx8p  
//if(count>4) q0iJy@?A  
// siteStop(); maXg(Lu  
} d'RvpoM  
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System.err.println("文件下载结束！"); {drc}BL_  
} 5~|{:29X  
catch(Exception e){e.printStackTrace ();} BDTL5N  
} L=l&,ENy  
);$99t  
TaN{xpo  
//获得文件长度 /8FmPCp}r  
public long getFileSize() _y@].G  
{ O$<>v\NC?  
int nFileLength = -1; :OG I|[  
try{ iQ;p59wSzL  
URL url = new URL(siteInfoBean.getSSiteURL()); T#))
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wY8:j  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y()"2CCV  
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int responseCode=httpConnection.getResponseCode(); 8R,<S-+v  
if(responseCode>=400) p49]{2GXb  
{ H$KO[mW}  
processErrorCode(responseCode); K:wI'N"N  
return -2; //-2 represent access is error %2?+:R5.  
} xT%`"eM}  
w&q[%(G_  
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String sHeader; WMSJU/-P  
JZ:@iI5>+  
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for(int i=1;;i++) CkT(\6B-  
{ DxJ;C09xNa  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]:P7}Kp
b  
//Utility.log(in.readLine()); nlwqSXw  
sHeader=httpConnection.getHeaderFieldKey(i); (N7uaZ?Z  
if(sHeader!=null)
V!W.P  
{ c$O8Rhx  
if(sHeader.equals("Content-Length")) ,o&C"sb  
{ X@rA2);6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); bMyld
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break; FSIiw#xzH  
} 5(3O/C{?~  
} "& ,ov#  
else fw%`[(hK  
break; CSO'``16  
} &{}Mds  
} (W ~K1]  
catch(IOException e){e.printStackTrace ();} i
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catch(Exception e){e.printStackTrace ();} WsI`!ez;D  

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Utility.log(nFileLength); >|$]=e,Z  
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return nFileLength; mdj%zJ8/  
} }LzBo\  
JVZ-nHf(9  
,_2-Op
  
//保存下载信息（文件指针位置） T5S4,.o9W  
private void write_nPos() Yj%]|E-  
{ p3I"LY  
try{ 3JCo!n0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +yGQt3U  
output.writeInt(nStartPos.length); ,T$ts  
for(int i=0;i<nStartPos.length;i++) qJhsMo2
IH  
{ j~CnMKN  
// output.writeLong(nPos); (|gQ i{8  
output.writeLong(fileSplitterFetch.nStartPos); )@PnpC%H  
output.writeLong(fileSplitterFetch.nEndPos); $></%S2g  
} ?'
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output.close(); JMb_00r  
} dftBD  
catch(IOException e){e.printStackTrace ();} s]arNaaA  
catch(Exception e){e.printStackTrace ();} bSB%hFp=Cp  
} ;G[V:.o-  
4,9$udiGY  
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//读取保存的下载信息（文件指针位置） *{g3ia  
private void read_nPos() y0zMK4b  
{ +P/kfY"  
try{ wP!X)p\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); p3Sh%=HE'  
int nCount = input.readInt(); A#{63_H  
nStartPos = new long[nCount]; bsIG1&n'T  
nEndPos = new long[nCount]; K\Ea\b[  
for(int i=0;i<nStartPos.length;i++) p_FM 2K7!  
{ ]c.w+<  
nStartPos = input.readLong(); wQ}r/2n|^  
nEndPos = input.readLong(); RBX<>*  
} #[93$)Gd!  
input.close(); IGlR,tw_/  
} i5,iJe0cA  
catch(IOException e){e.printStackTrace ();} ).T&fa"  
catch(Exception e){e.printStackTrace ();} >=~\b  
} 2]>O ZhS  
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private void processErrorCode(int nErrorCode) NYm"I`5w  
{ !`DRJ)h  
System.err.println("Error Code : " + nErrorCode);  T]#V  
} <`H0i*|Ued  
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9d(\/ 7  
//停止文件下载 h^M_yz-f  
public void siteStop()  bGRt  
{ s|[>@~gXk  
bStop = true; WK~H]w  
for(int i=0;i<nStartPos.length;i++) O%bbyR2  
fileSplitterFetch.splitterStop(); ajYe?z  
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} e8m,q~%#/  
} H;H=8'  
//负责部分文件的抓取 @u~S!(7.Wi  
**FileSplitterFetch.java baxZ>KNi  
*/ nm'l}/Ug  
package NetFox; dC11kqqj  
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import java.io.*; 9}573M  
import java.net.*; zWsr|= [  
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public class FileSplitterFetch extends Thread { Y\|#Lu>B  
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String sURL; //File URL eA!o#O.  
long nStartPos; //File Snippet Start Position lqzt[zgN  
long nEndPos; //File Snippet End Position D3pz69W  
int nThreadID; //Thread's ID 6Q.S  
boolean bDownOver = false; //Downing is over QY\k3hiqn  
boolean bStop = false; //Stop identical dcz?5O_{,  
FileAccessI fileAccessI = null; //File Access interface q z)2a2C  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException rpNb.  
{ .`or^`X3  
this.sURL = sURL; [ks_wvY:'  
this.nStartPos = nStart; /y$Omc^  
this.nEndPos = nEnd; hor7~u+  
nThreadID = id; d} >Po%r:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 bIQ,=EA1  
}
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public void run() 3Ax'v|&Hg  
{ ]#!uke Q  
while(nStartPos < nEndPos && !bStop) } ueFy<F  
{ aDlp>p^E>  
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try{ @W,jy$U  
URL url = new URL(sURL); /l$x}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BK$y>= `  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'Zx5+rM${}  
String sProperty = "bytes="+nStartPos+"-"; V<ESjK8  
httpConnection.setRequestProperty("RANGE",sProperty); XLh)$rZ  
Utility.log(sProperty); &kb`)F3nU  
FD=% 4#|  
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InputStream input = httpConnection.getInputStream(); xR7ZqTcw  
//logResponseHead(httpConnection); Gnc`CyN:H  
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~!S3J2kG{  
byte[] b = new byte[1024]; )^(*B6;z5  
int nRead; Zxk~X}K\P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) iL/
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1  
{ UG| /Px ]  
nStartPos += fileAccessI.write(b,0,nRead); st'T._  
//if(nThreadID == 1) U(&c@u%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %nA})nA7=  
} F^!D[:;jK  
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Utility.log("Thread " + nThreadID + " is over!"); HC`0Ni1  
bDownOver = true; 5Xy(za  
//nPos = fileAccessI.write (b,0,nRead); >.:+|Br`  
} n@
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catch(Exception e){e.printStackTrace ();} =SDex.ZK]
 
} F72#vS j  
} d^=BXCoC  
>w,L=z=  
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//打印回应的头信息 C{)1#<`  
public void logResponseHead(HttpURLConnection con) C6+ 5G-Z  
{ O\}C`CiC  
for(int i=1;;i++) YAi-eL67l  
{ {v={q1  
String header=con.getHeaderFieldKey(i); _H]\  
if(header!=null) @T1G#[C~t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]m1fo'  
Utility.log(header+" : "+con.getHeaderField(header)); UpoSC  
else -@Ap;,=  
break; GwWK'F'2  
} d0J/"<  
} B-I4(w($  
.)E#*kLWR  
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public void splitterStop() so))J`ca)  
{ nz 10/nw  
bStop = true; R'c*CLaiE  
} *CN *G"  
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@2(u=E:^  
} )"x6V""Rb  
"M%R{pGA7  
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/*
]4~Yi1]  
**FileAccess.java +IZ=E >a  
*//文件访问(定位，写) VZ]iep  
package NetFox; "&(/bdah?&  
import java.io.*; H4M=&"ll}  
Ae5A@4  
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public class FileAccessI implements Serializable{ &1\/B  
oXo
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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 *tjaac;z<J  
RandomAccessFile oSavedFile; @f[-  
long nPos; +.cpZqWn3  
}n)0}U5;0  
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public FileAccessI() throws IOException g-3^</_fZ  
{ +'F;\E  
this("",0); y_PA9#v7  
} #N{]  
A%w9Da?B  
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public FileAccessI(String sName,long nPos) throws IOException =7!s8D,[  
{ rfV'EjiM}  
oSavedFile = new RandomAccessFile(sName,"rw"); (Jp~=6&lKf  
this.nPos = nPos; Y7GsL7I  
oSavedFile.seek(nPos); py6<QoGV  
} a)|y0w)vV  
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C-pR$WM:HN  
public synchronized int write(byte[] b,int nStart,int nLen) \g0vzo"u  
{ r3V1l
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int n = -1; ?NE/}?a  
try{ RO3LZBL  
oSavedFile.write(b,nStart,nLen); lpT&v;$`  
n = nLen; &M-vKc"d  
} sRB=<E*_  
catch(IOException e) # epP~J_f  
{ wv~:^v'  
e.printStackTrace (); @Y0
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} xMbgBx4+  
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3f=ZNJ>  
return n; w4fKh  
} j"Jf|Hq $  
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} [G 9Pb)  
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k26C=tlkv"  
/* 0 u*a=f=  
**SiteInfoBean.java RvG=GJJ9  
*/ Q{~g<G  
package NetFox; @x `X|>&  
%??v?M*  
2ZxhV4\  
public class SiteInfoBean { 1zRYd`IPoq  
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628iN%[-  
private String sSiteURL; //Site's URL NV5qF/<M  
private String sFilePath; //Saved File's Path #cQ5-R-1  
private String sFileName; //Saved File's Name (iKJ~bJ  
private int nSplitter; //Count of Splited Downloading File <
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6B]=\H  
|!FQQ(1b  
public SiteInfoBean() l/3=o}8q  
{//nSplitter的缺省值为5 ^cZ< .d2  
//default value of nSplitter is 5 ##mZ97>$  
this("","","",5); GVhqNy   
} KHx2$*E_  
P'wo+Tn*  
5mamWPw  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) L#SW!  
{ #ss/mvc3  
sSiteURL= sURL; )4rt-_t<  
sFilePath = sPath; GZO:lDdA  
sFileName = sName; :E}
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this.nSplitter = nSpiltter; 4dixHpq'  
:]:)c8!6  
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} !h1:AW_iz  
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[~Ky{:@)[  
public String getSSiteURL() s[GHDQ;!  
{ ZtZ3I?%U3  
return sSiteURL; 1IoW}yT  
} _1[Wv?  
A~xw:[zy$a  
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public void setSSiteURL(String value) gaN/ kp  
{ UIDeMz  
sSiteURL = value; yH(
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} 3li$)S1z  
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public String getSFilePath() Z*M
{  
{ N.mRay,  
return sFilePath; {9(0s| pr  
} ~QSX 1w"  
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5r)8MklZ  
public void setSFilePath(String value) R?u(aY)P  
{
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sFilePath = value; %Bw:6Y4LZ  
} xc*a(v0  
q\@_L.tc[  
&]YyV.
 
public String getSFileName() Ck#e54gJX  
{ T1q27I  
return sFileName; i&m_G5u88  
} U;/2\Ii  
QM8Ic,QFvo  
R*vQvO%)h  
public void setSFileName(String value) ,c"J[$i$  
{ |Uics:cQC  
sFileName = value; .K84"Gdx  
} lrZ]c:%k  
G_?U?:!AC  
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public int getNSplitter() I;Mm+5A  
{ 3!8(A/YP;  
return nSplitter; 4Q0ZY(2 EO  
} PP{9Y Vr  
P@PF"{S  
^'[QCwY~  
public void setNSplitter(int nCount) Lfn$Q3}O`$  
{ :!MEBqcU  
nSplitter = nCount; {U2AAQSa  
} HL&HY)W1gf  
} T/E=?kBR  
T#Q7L~?zY  
<oJ?
J^  
/* Zb2pZhkW  
**Utility.java #w
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*/ hu$eO'M_  
package NetFox;  >%;i@"  
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K ,NmDc^  
public class Utility { 8Azh&c  
,
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public Utility() vY
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{ 9HO9>^
 
{[#)Q.2  
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} O`0r'&n  
D2}^TIg  
//线程睡眠 )YgntI@  
public static void sleep(int nSecond) 3}FZg w .  
{ >=97~a+
.  
try{ ;&<N1  
Thread.sleep(nSecond); la<.B^  
} KO=$Hr?f;  
catch(Exception e) G+N1#0,q  
{ 1iY4|j;ahV  
e.printStackTrace (); iO?AY  
} #WZat ?-N  
} iXy1{=BDv  
FbroI>"e  
//日志 nEu:& 4  
public static void log(String sMsg) Ik^^8@z  
{ +Kb 7N, "  
System.err.println(sMsg); xh:I]('R  
} - (WH+  
h#Z["BG  
{
Vj&i.2,  
public static void log(int sMsg) w[d8#U  
{ F/ZFO5C%  
System.err.println(sMsg); |P]W#~Y-  
} }O7sP^  
} we[+6Z6J  
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]}lt^
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/* Y>
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**TestMethod.java Fc@R,9  
*/ 5c3-?u!  
package NetFox; ,2$<Pt;  
<4.Exha;=  
!DOyOTR&3  
public class TestMethod { by'KJxl[  
beo(7,=&  
h_?`ESI~  
public TestMethod() >I\B_q  
{ ///xx/weblogic60b2_win.exe Q&.uL}R  
try{ 0zNbux_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @\w}p E  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
{)"[_<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0Qa0  
fileFetch.start(); Lq5xp<  
} `sqr>QD  
catch(Exception e){e.printStackTrace ();} >\[]z^J  
OiQf=Uz\  
:wS&3:h  
} NH|I>vyN  
AwNr}9`  
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public static void main(String[] args) vcd
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{ " Bx@(  
new TestMethod(); 9{OO'at?  
} 6Yn>9llo}=  
} (*$F7oO<  
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