http断点续传简单实现（java)

/* 4>Y\Y$3  
**SiteFileFetch.java - -ZSl  
*/ WV,j <x9w  
package NetFox; r!)jxIL\  
import java.io.*; q/dja  
import java.net.*; Yg!xlrxA  
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public class SiteFileFetch extends Thread { e"]DIy4s  
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SiteInfoBean siteInfoBean = null; //文件信息Bean q:3HU<  
long[] nStartPos; //开始位置 cE7IHQ  
long[] nEndPos; //结束位置 f1RX`rXf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :eL ja*  
long nFileLength; //文件长度 *v0}S5^/"  
boolean bFirst = true; //是否第一次取文件 &)F#cVB  
boolean bStop = false; //停止标志 r1AG1Y  
File tmpFile; //文件下载的临时信息 oWcBQ|   
DataOutputStream output; //输出到文件的输出流 !~a1xI~s  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） V"W)u#4,  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8BggK6X  
{ t_{rKb,  
siteInfoBean = bean; 9p%8VDF=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); hgI;^ia  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {GKqOu  
if(tmpFile.exists ()) FW,@.CX  
{ =7 ${bp!  
bFirst = false; +I_p\/J?w/  
read_nPos(); F'3-*>]P  
} Qhsk09K_=4  
else K91.-k3)$  
{ _sI\
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nStartPos = new long[bean.getNSplitter()]; kz?
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nEndPos = new long[bean.getNSplitter()]; <:Z-zQp)?  
} TI^M9;b  
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} EP}NT)z,{  
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public void run() z!/ MBM  
{ drEND`,@6|  
//获得文件长度 N cnL-k.  
//分割文件 O*y@4AR"S  
//实例FileSplitterFetch d}_%xkC  
//启动FileSplitterFetch线程 u|uPvbM  
//等待子线程返回 \<4Hp_2?  
try{ Kvf
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if(bFirst) {Wh7>*p{3  
{ XY1b_uY  
nFileLength = getFileSize(); r4(Cb_  
if(nFileLength == -1) p@bcf5'  
{ d@0&  
System.err.println("File Length is not known!"); d vTsbs/6  
} 4>$weu^  
else if(nFileLength == -2) {rWFgn4Li  
{ _$YT*o@0J  
System.err.println("File is not access!"); a<ztA:xt|1  
} ( R0>0f@  
else 990sE t?  
{ >Vv
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for(int i=0;i<nStartPos.length;i++) ! fSM6Vo  
{ )OgQ&,#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _;yi
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} X__>r ?oJ  
for(int i=0;i<nEndPos.length-1;i++) -L)b;0%  
{ Z2wgfP`  
nEndPos = nStartPos[i+1]; m_n*_tX  
} H<bK9k)E  
nEndPos[nEndPos.length-1] = nFileLength; 4_B1qN
 
} ("$ ,FRTQ:  
} Z_Z; g]|!  
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b3RCsIz  
//启动子线程 8>y!=+9_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (hv>vfY@  
for(int i=0;i<nStartPos.length;i++) 8wQ|Ep\  
{ eX9Hwq4X44  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BvA09lK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5,n{-V  
nStartPos,nEndPos,i); aur4Ky> :  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;[>g(W+  
fileSplitterFetch.start(); U`h>[9  
} /o)o7$6Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )^'g2gVK+p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PWw2;3`-6w  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /y<nAGtD&  
nEndPos = " + nFileLength); !<P|:Oo*Dl  
// fileSplitterFetch[nPos.length-1].start(); bn8`$FA^  
Yo$ xz  
bEz1@"~ p  
//等待子线程结束 ^&mJDR
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//int count = 0; erC)2{m  
//是否结束while循环 ; OpN&q+  
boolean breakWhile = false; |`50Tf\J  
 #mDeA>b  
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while(!bStop) o :tz_5  
{ 6]*~!al?  
write_nPos(); uK5&HdoM  
Utility.sleep(500); RXF%A5FXh  
breakWhile = true; Pb(XR+  
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D'!
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for(int i=0;i<nStartPos.length;i++) M_Qv{   
{ aN/0'V|&ym  
if(!fileSplitterFetch.bDownOver) |dxcEjcY_  
{ ojA i2uz  
breakWhile = false; s^n}m#T  
break; 8 FqhSzw  
} M#PutrH  
} K3WhF  
if(breakWhile) ! 9U  
break; /s\_"p  
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.1&~@e%=-  
//count++; }zkMo?  
//if(count>4) 4R~f  
// siteStop(); *<[Nvk^  
} >O:31Uk  
}95;qyQ$  
E_[)z%&n2  
System.err.println("文件下载结束！"); *61+Fzr  
} q*^F"D:?k  
catch(Exception e){e.printStackTrace ();} 4%3R}-'mh  
} p? dXs^ c  
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//获得文件长度 .=nx5yz  
public long getFileSize() ![{>$Q?5  
{ @vC7j>*4B  
int nFileLength = -1; 45u\v2,C3  
try{ k[6xuyY]  
URL url = new URL(siteInfoBean.getSSiteURL()); "XU M$:D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5yHarC  
httpConnection.setRequestProperty("User-Agent","NetFox"); xgX"5Czvv`  
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int responseCode=httpConnection.getResponseCode(); >Y h7By  
if(responseCode>=400) 1%;o-F@  
{ ,1s,G]%M  
processErrorCode(responseCode); Gxtb@`f  
return -2; //-2 represent access is error I4%p?'i,C  
} 7h3#5Y  
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String sHeader; .!kO2/:6  
f~RS[h`:  
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for(int i=1;;i++) e+!+(D  
{ D?v)Xqw=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Q bg,q  
//Utility.log(in.readLine()); $8{|25 *E  
sHeader=httpConnection.getHeaderFieldKey(i); QEavb
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if(sHeader!=null) @-~ )M_  
{ Q UQ"2oC  
if(sHeader.equals("Content-Length")) m5G9 B-\?  
{ : *~}\M*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8+L,a_q-  
break; wClX3l>y  
} M%3\]&  
} rl\$a2_+  
else [F^qa/vJ10  
break; :`9hgd/9  
} [BH^SvE  
} nj (/It  
catch(IOException e){e.printStackTrace ();} ~4YLPMGKl  
catch(Exception e){e.printStackTrace ();} {EoRY/]  
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Utility.log(nFileLength); ]<pnHh+2A  
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return nFileLength; Y=%SK8]Q;  
} rcC}4mNe  
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//保存下载信息（文件指针位置） uG|d7LS,%  
private void write_nPos() PP{CK4  
{ DA/l`Pn  
try{ ]8}+%P,Q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sg.8Sd"]7  
output.writeInt(nStartPos.length); QW5S=7  
for(int i=0;i<nStartPos.length;i++) t3#My2=  
{ \k#|5W  
// output.writeLong(nPos); an4^(SY  
output.writeLong(fileSplitterFetch.nStartPos); ,~R`@5+  
output.writeLong(fileSplitterFetch.nEndPos); BVKr
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} "5KJ /7q!  
output.close(); g1je':  
} t8"*jt  
catch(IOException e){e.printStackTrace ();} )YDuq(g&  
catch(Exception e){e.printStackTrace ();} RG'Ft]l92N  
} %TY;}V59b  
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//读取保存的下载信息（文件指针位置） p)t1]<,Of  
private void read_nPos() _h% :Tu  
{ $=x1_  
try{ K+0&~XU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -/#VD&MJO=  
int nCount = input.readInt(); SWAggW)  
nStartPos = new long[nCount]; 73-*
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nEndPos = new long[nCount]; "l-L-sc,  
for(int i=0;i<nStartPos.length;i++) (1 "unP-  
{ N2?o6)  
nStartPos = input.readLong(); Vv
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nEndPos = input.readLong(); }Htnhom0n  
} |Ef\B]Ns  
input.close(); pJ` M5pF  
} A9*( O)  
catch(IOException e){e.printStackTrace ();} [j6EzMN  
catch(Exception e){e.printStackTrace ();} 4Y):d!'b  
} W"m\|x  
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private void processErrorCode(int nErrorCode) \m3'4#  
{ rjmKe*_1V  
System.err.println("Error Code : " + nErrorCode); y:U'3G-
  
} WIytgM  
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Q*S|SH-cZ0  
//停止文件下载 w/8`]q  
public void siteStop() xbh4j!FD$  
{ l7 +#gPA  
bStop = true; Di[}y;  
for(int i=0;i<nStartPos.length;i++) ZZkxEq+D  
fileSplitterFetch.splitterStop(); p2c4 <f-M  
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}{! #`'s  
} 1v)X]nW  
} !]%M  
//负责部分文件的抓取 a@|/D\C  
**FileSplitterFetch.java R^}}-Dvr  
*/ G}o?lo\#h  
package NetFox; L<kIzB !  
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import java.io.*; Wq bfZx  
import java.net.*; g/)$-Z)Nu  
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public class FileSplitterFetch extends Thread { .k{omr&Dy5  
|G2hm8 Y  
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String sURL; //File URL 1E(~x;*)  
long nStartPos; //File Snippet Start Position N30w^W&  
long nEndPos; //File Snippet End Position 3Y\7+975m  
int nThreadID; //Thread's ID 45Z"U<I,9  
boolean bDownOver = false; //Downing is over *cjH]MQ0Ak  
boolean bStop = false; //Stop identical K3eYeXV  
FileAccessI fileAccessI = null; //File Access interface R&z)  
]dXHjOpA  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `w_?9^7mH  
{ 4T*RJ3Fz!  
this.sURL = sURL; y-UutI&  
this.nStartPos = nStart; tMN^"sjf*  
this.nEndPos = nEnd; 5e!YYt>  
nThreadID = id; 0D;MW  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %ZNp  
} -1tdyCez  
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|!r.p_Zt  
public void run() N=qe*Rlf  
{ TBfX1v|Z)  
while(nStartPos < nEndPos && !bStop) O"otzla  
{ 5zebH  
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go, Hfb  
try{ N4 O'{  
URL url = new URL(sURL); rm7$i9DH2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,/.U'{  
httpConnection.setRequestProperty("User-Agent","NetFox"); jTNfGu0x  
String sProperty = "bytes="+nStartPos+"-"; F&{RP>  
httpConnection.setRequestProperty("RANGE",sProperty); S ("Zzq`  
Utility.log(sProperty); Vb|;@*=R&Q  
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*>Z|!{bI  
InputStream input = httpConnection.getInputStream(); :n3)vK   
//logResponseHead(httpConnection); 8S&Kf>D  
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byte[] b = new byte[1024]; Qm|Q0u  
int nRead; %G%##wv:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #+V5$  
{ [OI&_WIw  
nStartPos += fileAccessI.write(b,0,nRead); 7wt2|$Qz  
//if(nThreadID == 1) %21i#R`E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =-M)2&~L~  
} nZF(92
v  
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Utility.log("Thread " + nThreadID + " is over!"); } z4=3'  
bDownOver = true; UOn L^Z}  
//nPos = fileAccessI.write (b,0,nRead);
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} *}9i@DP1,  
catch(Exception e){e.printStackTrace ();} q&IO9/[dk  
} LEM{$Fxo&  
} RjO9E.nm  
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=<-tD<  
//打印回应的头信息 o0-7#2  
public void logResponseHead(HttpURLConnection con) AL.zF\?  
{ /o=V (  
for(int i=1;;i++) K\ww,S  
{ 2W
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String header=con.getHeaderFieldKey(i); {~g(W
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if(header!=null) 6qA48:/F=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VjU;[  
Utility.log(header+" : "+con.getHeaderField(header)); =RR225  
else @l9qH1  
break; 0NLoqq  
} QK0  
} &tFVW[(  
sQ65QJtt0A  
; 6Wlu3I  
public void splitterStop() _m!TUT8o  
{ |irqv< r  
bStop = true; -GkNA"2M[  
} ~L!*p0dS^  
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} 'hl>pso.  
.BsZ.!MPL(  
eTI<WFRc_  
/* b _fI1f|  
**FileAccess.java z\Y+5<a  
*//文件访问(定位，写) E3gR%t  
package NetFox; e";r_J3w  
import java.io.*; U;n$  
7%Zl^c>q  
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public class FileAccessI implements Serializable{ \Q"o\:IoIT  
ScrEtN  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节
! /Z{uy  
RandomAccessFile oSavedFile; = GirUW D  
long nPos; I__|+%oC  
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public FileAccessI() throws IOException N9r}nqCN  
{ :+ef|,:`/  
this("",0); lkf(t&vL2  
} .gNWDk0$Y  

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public FileAccessI(String sName,long nPos) throws IOException CIh@H6|  
{ D%v4B`4ua'  
oSavedFile = new RandomAccessFile(sName,"rw"); !dB {E  
this.nPos = nPos; :8}QKp  
oSavedFile.seek(nPos); ReOp,A/y  
}
2=X2M  
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8P r H"pI  
public synchronized int write(byte[] b,int nStart,int nLen) @NGK2J  
{ >W"gr]R<  
int n = -1; yc5C`r+6  
try{ o.t$hv|  
oSavedFile.write(b,nStart,nLen); wZVY h  
n = nLen; $x5P5^Y  
} 2wE?O^J  
catch(IOException e) bs!N~,6h  
{ uR{HCZ-  
e.printStackTrace (); gB@Xi*  
} X l#P@60  
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pN/)$6=  
return n; ghm5g/  
} `e]L.P_e?  
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} }fnp}L  
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/* G?!b00H  
**SiteInfoBean.java an^"_#8DA@  
*/ T1hr5V<U  
package NetFox; $$~
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public class SiteInfoBean { (&0%![j&  
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private String sSiteURL; //Site's URL |cStN[97%  
private String sFilePath; //Saved File's Path +9G GC  
private String sFileName; //Saved File's Name B7(~m8:eH7  
private int nSplitter; //Count of Splited Downloading File ]&\HAmOQS  
C{!L +]/  
IRNL(9H  
public SiteInfoBean() !Uz{dFJf;  
{//nSplitter的缺省值为5 E%OY7zf`%  
//default value of nSplitter is 5 m8eyAvi6  
this("","","",5); "l!WO`.zp=  
} |t*(]U2O0  
i`/_^Fndyu  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) k@U8K(:x  
{ 'HTr02riY  
sSiteURL= sURL; mZ 39 s  
sFilePath = sPath; [2#5;')  
sFileName = sName; BDSZ'  
this.nSplitter = nSpiltter; fyPpzA0  
3Yf&F([t  
'_,/N!-V  
} e5KsKzu a  
m7wD#?lm  
~>&7~N8  
public String getSSiteURL() jY%&G#4  
{ ^;jJVYx-PP  
return sSiteURL; nmZz`P
9g  
} "MHm9D?5  
WZO8|hY  
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public void setSSiteURL(String value) {Vw+~8  
{ r_nB-\  
sSiteURL = value; W1'F)5(?7  
} wqB{cr}!  
VZo[\sWf  
k#Qav1_  
public String getSFilePath() Jb~$Vrdy  
{ |S.G#za  
return sFilePath; 3/c3e
{,!  
} F: %-x=q  
A>WMPe:sSS  
i ,Cvnp6Lv  
public void setSFilePath(String value) ,5oe8\uz  
{ u3 k%  
sFilePath = value; P^V,"B8t  
} HS>(y2}'  
|,3s]b`  
R<.<wQ4I  
public String getSFileName() Pyh+HD\  
{ j1{|3#5V  
return sFileName; oV"d%ks  
} ]<b$k  
0K/Pth"*  
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public void setSFileName(String value) s~e<Pr?yu  
{ ;1qE:x}
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sFileName = value; G
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} ^b|Z<oF  
@}[>*Xy%  
\f| Hk*@  
public int getNSplitter() ZK:dhwer  
{ <0lXJqd  
return nSplitter; /`(Kbwh  
} s18o,Zs'  
TdG
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;R[  xo!  
public void setNSplitter(int nCount) AI KLJvte  
{ *u LOoq  
nSplitter = nCount; n>Cl;cN=  
} z4t.-9(C  
} #,dNhUV#  
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/* Oi#4|*b{W  
**Utility.java $cl[Qcw  
*/ 1.S7MSpTV  
package NetFox; U-RR>j  
?O(@BT  
R7)\wP*l5  
public class Utility { JFAmND;+  
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public Utility() 2MT_5j5[N  
{ H~Z$pk%  
v[$-)vs*ag  
:r4]8X-
 
} Q6>7{\8l  
zzlqj){F  
//线程睡眠 |gXtP-  
public static void sleep(int nSecond) TtZZjeg+V  
{ P9d%80(b4  
try{ yH`4sd  
Thread.sleep(nSecond); 7JC^+rk  
} 2T3TD%  
catch(Exception e) L >* F8|g  
{ }s*H|z  
e.printStackTrace (); euxkw]`h6  
} O$dcy!  
} 7CKpt.Sz6  
D8S?xK7[  
//日志 LwPZRE#  
public static void log(String sMsg) :ik$@5wp  
{ =1!,A  
System.err.println(sMsg); U,G!u=+  
} CsJ38]=Mt  
25bbuhss  
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public static void log(int sMsg) #9R[%R7Nz  
{ =O~ J  
System.err.println(sMsg); Ark+Df/  
} y#Cp Vm#!>  
} 3Jt7IM!9[  
^A&i$RRO  
4=;.<  
/* MU  }<-1  
**TestMethod.java 8Ce|Q8<8]  
*/ |3Fo4K%+  
package NetFox; N}$$<i2o  
p3m!Iota  
`&3hfiI}  
public class TestMethod { R04%;p:k#  
dz3KBiq  
<N4)X"s  
public TestMethod()  <>|&%gmz  
{ ///xx/weblogic60b2_win.exe /*V:Lh  
try{ dkHye>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); tQ,,krw~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); SxX2+|0g`g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^)JUl!5j]C  
fileFetch.start(); Fwu:x.(  
} AZj`o  
catch(Exception e){e.printStackTrace ();} `6R.*hq  
>A]U.C  
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} gs xT  
G}2DZ=&>'  
8!R +wy  
public static void main(String[] args) s8r|48I#;  
{ ^~p^N <  
new TestMethod(); ;^[VqFpeS  
} v+), uj  
} bOB<m4  
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