http断点续传简单实现（java)

/* X3<<f`X  
**SiteFileFetch.java gM^ Hs7o,  
*/ Jd7+~isu~  
package NetFox; P8:k"i/6J  
import java.io.*; nH/V2>Lm  
import java.net.*; g.i
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public class SiteFileFetch extends Thread { ./rNq!*a  
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[
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SiteInfoBean siteInfoBean = null; //文件信息Bean @m<xpel  
long[] nStartPos; //开始位置 v0apEjT  
long[] nEndPos; //结束位置 W(9-XlYKE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }BzV<8F  
long nFileLength; //文件长度 3.xsCcmP  
boolean bFirst = true; //是否第一次取文件 F  MHpa  
boolean bStop = false; //停止标志 6Y`eYp5A  
File tmpFile; //文件下载的临时信息 [yW0U:m  
DataOutputStream output; //输出到文件的输出流 G ZDyw9  
#JWW ;M6F  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _RST[B.u6  
public SiteFileFetch(SiteInfoBean bean) throws IOException Cevl#c
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{ ~Yb5FYE  
siteInfoBean = bean; es6!p 7p?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 'W@X139zq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); e)zE*9  
if(tmpFile.exists ()) )4toBDg"  
{ 3ktjMVy\  
bFirst = false; >DP9S@W  
read_nPos(); 7b_t%G"  
} )CD4k:bm  
else }i^]uW*h  
{ I~-W4
{  
nStartPos = new long[bean.getNSplitter()]; 1~zzQ:jAZ  
nEndPos = new long[bean.getNSplitter()]; onI%Jl sq  
} wa\Yc,R  
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} | (JxtQqQg  
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public void run() {E@Fk,  
{ k Pi%RvuQ  
//获得文件长度 p.A_,iE  
//分割文件 >E;kM B  
//实例FileSplitterFetch IW?).%F  
//启动FileSplitterFetch线程 ^a^b
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//等待子线程返回 c@7d4Jz  
try{ SR!EQ<  
if(bFirst) r'/&{?Je/  
{ qIS9.AL  
nFileLength = getFileSize(); j)xRzImu  
if(nFileLength == -1) #I8)|p?P  
{ n("Xa#mY[  
System.err.println("File Length is not known!"); u1a0w  
} U6cpj  
else if(nFileLength == -2) U*(/eEtd-  
{ b+Sq[  
System.err.println("File is not access!"); kl%%b"h'  
} h;cl+c|B  
else nWb*u  
{ <+Eu.K&  
for(int i=0;i<nStartPos.length;i++) SQ'\Kd=  
{ '5V}Z3zJ/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J=7.-R|t  
} HVjN<HIqM  
for(int i=0;i<nEndPos.length-1;i++) C# zYZ JZ  
{ ;E:vsVK  
nEndPos = nStartPos[i+1]; jV{?.0/h|  
} nilis-Bk_  
nEndPos[nEndPos.length-1] = nFileLength; 3r^Ls[ey  
} $~7uDq  
} "o_s=^U  
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//启动子线程 )|3BS`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,Tp:. "  
for(int i=0;i<nStartPos.length;i++) |"}oGL6-  
{ ]gjQy.c|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +pUG6.j%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xmVW6 ,<?  
nStartPos,nEndPos,i); 1.24ZX  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^AhV1rBB  
fileSplitterFetch.start(); E'-lpE  
} `PY=B$?{4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CWBlDz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %_Q+@9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =csh=V@s  
nEndPos = " + nFileLength); ca=sc[ $+  
// fileSplitterFetch[nPos.length-1].start(); AQ%B&Q(V1  
W&~\@j]!D  
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//等待子线程结束 &u`EYxT  
//int count = 0; srlxp_^  
//是否结束while循环 1X5M
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boolean breakWhile = false; "DO|B=EejP  
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while(!bStop) `T\_Wje(  
{ 3</W}]$)p  
write_nPos(); 7D(Eo{ue  
Utility.sleep(500); h+rW%`B  
breakWhile = true; g^l~AR  
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for(int i=0;i<nStartPos.length;i++) jn +*G<NJ  
{ lVv'_9yg  
if(!fileSplitterFetch.bDownOver) o9rZ&Q<  
{ %W}YtDf\  
breakWhile = false; &=*sN`  
break; q2b>Z6!5  
} M!YGv   
} 'yo-`nNFD  
if(breakWhile) jl>jy6T  
break; lY&Sx{-  
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//count++; |2E:]wT}qg  
//if(count>4) r^7eK
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// siteStop(); ){LU>MW{&  
} l(Ya,/4  
*(s0X[-  
{SF'YbY  
System.err.println("文件下载结束！"); uZM%F)  
} ?8qN8rk^+  
catch(Exception e){e.printStackTrace ();} `_()|;!y  
} wRdN(`;v  
cOf.z)kf6  
!hFzIp  
//获得文件长度 -FF#+Z$  
public long getFileSize() <(t{C8>g%  
{ 0.S7uH%
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int nFileLength = -1; d]USk&8  
try{ 3*T/ 7\  
URL url = new URL(siteInfoBean.getSSiteURL()); 75pn1*"gQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AJ>$`=  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q@"}v_r4  
-_xTs(;|8  
b
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int responseCode=httpConnection.getResponseCode(); 9?q ^yy  
if(responseCode>=400) o5['5?i}/  
{ NFyV02.  
processErrorCode(responseCode); ]UkqPtG;  
return -2; //-2 represent access is error .HN4xL  
} n%;4Fm
?  
r $[{sW  
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String sHeader; vmv6y*qU  
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for(int i=1;;i++) TS`m&N{i")  
{ 7^V`B^Vu  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); g*Pn_Yo[.  
//Utility.log(in.readLine()); 1g,Of
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sHeader=httpConnection.getHeaderFieldKey(i); ,k1ns?i9KH  
if(sHeader!=null)  Ci 'V  
{ aeVd.`lxM  
if(sHeader.equals("Content-Length")) IAWs}xIly  
{ 62kA(F0e,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); JC`;hY  
break; Q8A+\LR~)  
} h@]{j_$u  
} 3kh!dL3D  
else <>(v~a]  
break; v-8{mK`9\  
} P^ht$)Y  
} 0eKLp8;Lh
 
catch(IOException e){e.printStackTrace ();} P8#_E{f  
catch(Exception e){e.printStackTrace ();} 8QMMKOui\  
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Utility.log(nFileLength); FRL;fF  
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return nFileLength; N A_8<B^  
} EuA352x  
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//保存下载信息（文件指针位置） ZFh[xg'0  
private void write_nPos() e\O625  
{ V3T.EW  
try{ bMsThoePT
 
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?r*}1WsH  
output.writeInt(nStartPos.length); xSO5?eR"u  
for(int i=0;i<nStartPos.length;i++) a^^OI|?  
{  fOKAy'  
// output.writeLong(nPos); \rT>&o .i  
output.writeLong(fileSplitterFetch.nStartPos); vR pO0qG  
output.writeLong(fileSplitterFetch.nEndPos); 6mIeV0Q'  
} oLtzPC  
output.close(); Bs|#7mA[  
} \ [M4[Qlq  
catch(IOException e){e.printStackTrace ();} Gm> =s  
catch(Exception e){e.printStackTrace ();} .g7\+aiTUd  
} t8;nP[`  
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!HtW~8|:  
//读取保存的下载信息（文件指针位置） /!.]Y8yEH  
private void read_nPos() KU Mk:5 c  
{ U]B-B+
-  
try{ #)i+'L8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #s#BYbF  
int nCount = input.readInt(); E$A=*-u  
nStartPos = new long[nCount]; =s*4y$%
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nEndPos = new long[nCount]; &os:h] C  
for(int i=0;i<nStartPos.length;i++) * bhb=~  
{ m?1r@!/y  
nStartPos = input.readLong(); {lUaN0O:  
nEndPos = input.readLong(); F7/%,vf  
} %  .ss  
input.close(); )3V1aC  
}  @k#xr  
catch(IOException e){e.printStackTrace ();} )cL`$h4DD  
catch(Exception e){e.printStackTrace ();} 3hEbM'L  
} 91nB?8ZE6,  
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private void processErrorCode(int nErrorCode) epG =)gd=8  
{ Z.rhM[*+0C  
System.err.println("Error Code : " + nErrorCode); Mhb~wDQl  
}
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//停止文件下载 aWP9i&  
public void siteStop() p;D {?H/  
{ fP8bWZ{  
bStop = true; Fiw^twz5  
for(int i=0;i<nStartPos.length;i++) e? |4O<@  
fileSplitterFetch.splitterStop(); !t{  
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} `D$RL*C;M`  
} o{l]


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//负责部分文件的抓取 |TF6&$>d  
**FileSplitterFetch.java V@EyU/VJ  
*/ +CXq41g"c  
package NetFox; _fHj8- s/  
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1CJAFi>%D  
import java.io.*; dYlVJ_0Zr  
import java.net.*; 7xO~v23oe  
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public class FileSplitterFetch extends Thread { %F}d'TPx  
6?JvvS5  
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String sURL; //File URL *<h)q)HS  
long nStartPos; //File Snippet Start Position hx4c`fOs  
long nEndPos; //File Snippet End Position Mp[2Auf  
int nThreadID; //Thread's ID `7?EE1o  
boolean bDownOver = false; //Downing is over m,}GP^<1i  
boolean bStop = false; //Stop identical pTncx%!W5  
FileAccessI fileAccessI = null; //File Access interface b?,=|H  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $ERiBALN:  
{
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this.sURL = sURL; hrXk7}9  
this.nStartPos = nStart; cJM.Q_I}Y  
this.nEndPos = nEnd; 1?Tj  
nThreadID = id; 7?);wh7`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7mtg  
} dx$+,R~y  
Pa$"c?QUy  
#3A|Z=,
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public void run() "g!ek3w(  
{ .SNg
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while(nStartPos < nEndPos && !bStop) x,fL656t  
{ IlB*JJnl  
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try{ tX,x%(  
URL url = new URL(sURL); Q-1Xgw!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g0-rQ
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httpConnection.setRequestProperty("User-Agent","NetFox"); 8`90a\t'Z  
String sProperty = "bytes="+nStartPos+"-"; wyLyPJv  
httpConnection.setRequestProperty("RANGE",sProperty); ^ohIJcI-  
Utility.log(sProperty); QUh`kt(E  
}d5~w[  
P'*Fd3B#A=  
InputStream input = httpConnection.getInputStream(); bL+}n8B  
//logResponseHead(httpConnection); \5Y<UJKi  
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byte[] b = new byte[1024]; W! J@30  
int nRead; _>8Q{N\- {  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) rd)W+W9  
{ KleiX7  
nStartPos += fileAccessI.write(b,0,nRead); MT$)A:"  
//if(nThreadID == 1) eo.B0NZsF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a|4Q6Ycu  
} xJA{Hws  
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3e1P!^'\  
Utility.log("Thread " + nThreadID + " is over!"); IaU%L6Q]  
bDownOver = true; }<*KM)%  
//nPos = fileAccessI.write (b,0,nRead); MV07RjeS  
} i4XiwjCHN  
catch(Exception e){e.printStackTrace ();} '|<S`,'#hg  
} ~@#a*="  
} ,_Kr}RH  
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;k,@^f8  
//打印回应的头信息 y*p02\)  
public void logResponseHead(HttpURLConnection con) xErb11  
{ Cl{Ar8d}  
for(int i=1;;i++) 2u+!7D!w$  
{ g!9|1z  
String header=con.getHeaderFieldKey(i); @7KG0<]h  
if(header!=null) $g/h=w@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); B&6lG!K'?  
Utility.log(header+" : "+con.getHeaderField(header)); !e*T. 1Kz  
else tBX71d
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break; W+5. lf=2>  
} v G9>e&Be  
} E%Ww)P  
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public void splitterStop() Ivj=?[c|  
{ |qz%6w=  
bStop = true; -Tn%O|#K  
} ZY@ntV?  
oR/_{#Mz"  

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} ;mvVo-r*q  
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9%1J..c  
/* $2RSYI`py  
**FileAccess.java "Mhn?PTq  
*//文件访问(定位，写) i'4.w?OZ  
package NetFox; L"n)fe$  
import java.io.*; >[;=c0(  
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;{q*  
public class FileAccessI implements Serializable{ _(I6o  
WqF$-rBJG^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \4^rb?B  
RandomAccessFile oSavedFile; |"I)1[7  
long nPos; v(!:HK0oeT  
 >]~|Nf/i  
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public FileAccessI() throws IOException )%3T1 D/  
{ R&a$w8  
this("",0); 0;=-x"  
} ai-rF^ehC  
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h /^bRs`;  
public FileAccessI(String sName,long nPos) throws IOException ~BX=n9  
{ I.GoY[u_%  
oSavedFile = new RandomAccessFile(sName,"rw"); |ns?c0rM  
this.nPos = nPos; $LFL4Q  
oSavedFile.seek(nPos); R&J?XQ  
} ovBmo2W/  
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nP]!{J]  
public synchronized int write(byte[] b,int nStart,int nLen) \7"|'fz  
{ 'A3skznX{  
int n = -1; G{E`5KIvm  
try{ ^W,5A;*3  
oSavedFile.write(b,nStart,nLen); >3Q|k{97  
n = nLen; Xq&BL,lS  
} IT&,?u%  
catch(IOException e) rxH]'6kP  
{  1/2cb-V  
e.printStackTrace ();  7-!n-  
} ~"CGur P  
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:  
return n; v|o{AL:ei  
} `+"(GaZ  
.  yg#  
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} pX?3inQP%(  
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/* I/MY4?(T  
**SiteInfoBean.java bIAE?D  
*/ wG3b{0  
package NetFox; D3X4@sM  
7RL J  
VNHceH  
public class SiteInfoBean { hx$61E=  
1x:W 3.  
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private String sSiteURL; //Site's URL gM\>{ihM'  
private String sFilePath; //Saved File's Path =GPXuo  
private String sFileName; //Saved File's Name 4a+gM._+O  
private int nSplitter; //Count of Splited Downloading File ^H3N1eC,`F  
'|[V}K5m/f  
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public SiteInfoBean() xR/CP.dg  
{//nSplitter的缺省值为5 10Ik_L='  
//default value of nSplitter is 5 3R+%C*7  
this("","","",5); L7-BuW}&  
} si]VM_w6  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #1DEZ4]jjY  
{ $nO~A7  
sSiteURL= sURL; 7__[=)(b2X  
sFilePath = sPath; Q[biy{(b8  
sFileName = sName; XB7Aa)  
this.nSplitter = nSpiltter; K381B5
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_x,X0ncv]@  
pCs3-&rI3  
} Q)DEcx-|,  
"GO!^ZG]  
M:/NW-:  
public String getSSiteURL() /iU<\+ H  
{ .SD-6GVD  
return sSiteURL; Z-PBCU  
} PR%)3  
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public void setSSiteURL(String value) EZ)b E9  
{ &n6{wtBP  
sSiteURL = value; 1=R$ RI  
} 7g\v (P  
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public String getSFilePath() "cKD#  
{ oy^-?+  
return sFilePath; r3'J{-kl  
} U>2KjZB  
/ox7$|Jyr  
cRLw)"|  
public void setSFilePath(String value) W%L'nR~w$  
{ J!uG/Us  
sFilePath = value; ip-X r|Bq  
} N%dY.Fk  
=XR~
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g  
public String getSFileName() wL0[Slf}  
{ /wJ#-DZ  
return sFileName; d{S'6*`D  
} Fv^zSoi2  
$${I[2R)  
{=GmXd%D  
public void setSFileName(String value) cq I $9  
{ <:9ts@B  
sFileName = value; tWIOy6`  
} h4`8C]  
X:i?gRy"  
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public int getNSplitter() wn[)/*(,$(  
{ ~B;}jI]d[  
return nSplitter; ;fNCbyg4 I  
} ;J W]b]  
0AO^d[v  
~+\=X`y  
public void setNSplitter(int nCount) F$t]JM  
{ *:L"#20:R  
nSplitter = nCount; \!^=~` X-  
} 2.^{4 1:  
} n#X~"|U`  
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/* al[^pPK
Z  
**Utility.java $Tbsre\MJ  
*/ p/Ul[7A4e  
package NetFox; BE0l2[i?  
0F)v9EK(W4  
h.Qk{v  
public class Utility { w9|x{B  
|+Wn5iT  
s{^B98d+W  
public Utility() (_pw\zk>  
{ c6:uM1V{  
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} m"!SyN}&9?  
xT>9ZZcE  
//线程睡眠 'Ix@<$~i3F  
public static void sleep(int nSecond) zmhc\M?z  
{ z6`0Uv~  
try{ m7k }k)  
Thread.sleep(nSecond); ;^N lq3N  
} ,V1"Typ#<  
catch(Exception e) 63E6nW M  
{ Ek<Qz5)  
e.printStackTrace ();  xL15uWk-  
} 5t%8y!s  
} ,7wY
a&  
3jZGO9ttnS  
//日志 6w<rSUd'  
public static void log(String sMsg) ]T)N{"&N/  
{ EV( F!&  
System.err.println(sMsg); =dQ[I6  
} ^iONC&r  
V0^{Ss1M  
f&CQn.K"  
public static void log(int sMsg) "6d0j)YO  
{ i bzY&f  
System.err.println(sMsg); ;O7"!\  
} O+W<l
:|$  
} $IQPB_:  
o-bH3Jkb]&  
~u%$ 9IhM  
/* )h@PRDI_  
**TestMethod.java 4w+AOWjd  
*/ E3 % ~!ZC  
package NetFox; 1'/ [x(/]d  
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w  
public class TestMethod { )p>Cf_[.  

b>ZAkz)U+  
8gavcsVE[  
public TestMethod() %%K3J<5  
{ ///xx/weblogic60b2_win.exe t]SB.ja  
try{ Z}t;:yhR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _>vH%FY  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); H5 z1_O_+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); g)6>=Qo`8E  
fileFetch.start();
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} E2M<I;:EA  
catch(Exception e){e.printStackTrace ();} XQ=%a5w  
%.d.h;^T  
{

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} IM1&g7Qs2  
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public static void main(String[] args) -Kg.w*\H7/  
{ ?lkB{-%rQ  
new TestMethod(); |@_<^cV110  
} _FOIMjh%N  
} 7C'@g)@^/  
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