http断点续传简单实现（java)

/* ~ga`\%J  
**SiteFileFetch.java /8g^T")  
*/ s
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package NetFox; x`mN U  
import java.io.*; {{MRELipW  
import java.net.*; DRgTe&+  
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public class SiteFileFetch extends Thread { PGBQn#c<  
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); dT_  
SiteInfoBean siteInfoBean = null; //文件信息Bean be-~\@  
long[] nStartPos; //开始位置 jvFTR'R)=  
long[] nEndPos; //结束位置 M:3h e  
FileSplitterFetch[] fileSplitterFetch; //子线程对象
}36QsH8  
long nFileLength; //文件长度 ;u(<h?%e  
boolean bFirst = true; //是否第一次取文件 M8Z2Pg\0  
boolean bStop = false; //停止标志 "WK{ >T  
File tmpFile; //文件下载的临时信息 o=?C&f{  
DataOutputStream output; //输出到文件的输出流 5HO9+i  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） rKf-+6Na  
public SiteFileFetch(SiteInfoBean bean) throws IOException yA(K=?sq  
{ kO{s^_qR^c  
siteInfoBean = bean; /)(#{i*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;Tc`}2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^__Dd)(  
if(tmpFile.exists ()) ;R?I4}O#R8  
{ %V{7DA&C  
bFirst = false; uYil ?H{kH  
read_nPos(); nwaxz>;  
} ]=";IN:SU  
else GBFtr
 
{ D]~MC  
nStartPos = new long[bean.getNSplitter()]; _DNHc*  
nEndPos = new long[bean.getNSplitter()]; j;3[KLmuK%  
} o1Q7Th  
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} 3?P
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public void run() ixQJ[fH10  
{ aj,T)oDbt6  
//获得文件长度 I=9!Rs(QF  
//分割文件 +d!v}aJ  
//实例FileSplitterFetch %\r!7@Q  
//启动FileSplitterFetch线程 .h5[Q/*h  
//等待子线程返回 .]7Qu;L  
try{ )R  2.  
if(bFirst) HcV"X,7S  
{ snnbb0J
 
nFileLength = getFileSize(); q)vplV1A  
if(nFileLength == -1) sx51X^d  
{ "=za??
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System.err.println("File Length is not known!"); iVTGF<  
} ~Oq +IA~9  
else if(nFileLength == -2) X>. NFB  
{ *@)O7vB  
System.err.println("File is not access!");
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} z,bQ
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else QtqfG{  
{
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for(int i=0;i<nStartPos.length;i++) 'X!?vK^]p  
{ &0(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [.*;6y3  
} f'{]"^e=  
for(int i=0;i<nEndPos.length-1;i++) ku a) K!  
{ !o+_T?  
nEndPos = nStartPos[i+1]; ]mXLg:3B  
} |7pR)KH3  
nEndPos[nEndPos.length-1] = nFileLength; \Z/)Y;|mi0  
} ]&{ci  
} @L:>!<  
01. &>Duw  
a~!G%})'a  
//启动子线程 -yg?V2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^e>Wo7r  
for(int i=0;i<nStartPos.length;i++) 4bEf  
{ Z)xaJGbw  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ld7v3:M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), R &4Z*?S  
nStartPos,nEndPos,i); +@K09ge  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]a3iEA2 (  
fileSplitterFetch.start(); 3y~r72J  
} t 6^l`6:p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [j:[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -TOIc%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (V%`k'N7f  
nEndPos = " + nFileLength); =.`qixN  
// fileSplitterFetch[nPos.length-1].start(); %-AE]-/HI  
_ _>.,gL7  
:4T("a5aM  
//等待子线程结束 5`RiS]IO]  
//int count = 0; V$rlA'+1v  
//是否结束while循环 JQ-gn^tsy  
boolean breakWhile = false; 1G'`2ATF*  
3 Lsj}p  
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while(!bStop) cl*PFQp9j  
{ !'*c
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write_nPos(); ~|AwN [  
Utility.sleep(500); r]Ff{la5  
breakWhile = true; @hImk`&[N  
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for(int i=0;i<nStartPos.length;i++) lM[XS4/TRa  
{ b4""|P?L  
if(!fileSplitterFetch.bDownOver) n7YEG-J  
{ VCcr3Dx()F  
breakWhile = false; *I0-O*Xr  
break; rUjdq/I:Z  
} oejfU;+$  
} M}wXJ8aF?  
if(breakWhile) 5 VA(tzmCt  
break; q0bHB_|wL  
?`Y\)'}  
<x),,a=X  
//count++; :g\rQazxO  
//if(count>4) LR,7,DH$9'  
// siteStop(); ')$NfarQ.  
} kzS=g|_  
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System.err.println("文件下载结束！"); [|3>MZ2/  
} 92'wkS  
catch(Exception e){e.printStackTrace ();} KYxBVgJ  
} @i3bgx>_o  
9r2IuS0  
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//获得文件长度 *+b6B_u]  
public long getFileSize() <p?&udqD  
{ X}6#II  
int nFileLength = -1; *$M'`
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try{ y9|K|xO[  
URL url = new URL(siteInfoBean.getSSiteURL()); <d7V<&@o=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7
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httpConnection.setRequestProperty("User-Agent","NetFox"); j` /&r*zNq  
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int responseCode=httpConnection.getResponseCode(); ._96*r=o  
if(responseCode>=400) a/uo}[Y  
{ ag4`
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processErrorCode(responseCode); Bfv.$u00p  
return -2; //-2 represent access is error U^Tp6vN d  
} Pu>N_^ C  
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String sHeader; S2VVv$r_6  
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for(int i=1;;i++) qUF1XJZ}z  
{ 0X(]7b&~R  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !z zW2>  
//Utility.log(in.readLine()); qYp$fmj  
sHeader=httpConnection.getHeaderFieldKey(i); efuK  
if(sHeader!=null) 8)\M:s~7&  
{ qOG}[%<^n7  
if(sHeader.equals("Content-Length")) [W,-1.$!dM  
{ &(xUhX T  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r++i=SQax  
break; X
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} wp.TfKxw  
} !1uzX
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else >LF&EM]  
break; ! qJI'+_  
} e^$j5jV  
} H%z@h~s>  
catch(IOException e){e.printStackTrace ();} .#5l$['  
catch(Exception e){e.printStackTrace ();} &}`K^5K|O:  
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\`xkp[C  
Utility.log(nFileLength); *
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return nFileLength; []&(D_e"  
} 9F+P@Kp  
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hGP1(pH.  
//保存下载信息（文件指针位置） Vul+]h[!h  
private void write_nPos() <2P7utdZ   
{ )8{6+{5lu  
try{ j:1uP^.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i!MwBYk  
output.writeInt(nStartPos.length); c/u_KJFF-n  
for(int i=0;i<nStartPos.length;i++) }G1&]Wt_  
{ ;~sr$6  
// output.writeLong(nPos); V_L[P9  
output.writeLong(fileSplitterFetch.nStartPos); PtKTm\,JL0  
output.writeLong(fileSplitterFetch.nEndPos); Ws49ImCB  
} w
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output.close(); zb2K;%Qs+f  
} '
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catch(IOException e){e.printStackTrace ();} \-. Tg!Q6  
catch(Exception e){e.printStackTrace ();} ?(im+2  
} amB@N6*  
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+|C[-W7Sw  
//读取保存的下载信息（文件指针位置） >v0:qN7|  
private void read_nPos() {&nV4
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{ \/Ij7nD`l%  
try{ ZxS&4>.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3DoRE2}  
int nCount = input.readInt(); \].J-^=  
nStartPos = new long[nCount]; WSI Xj5R  
nEndPos = new long[nCount]; u+% tPe  
for(int i=0;i<nStartPos.length;i++) IM-`<~(I#  
{ =wA5P@  
nStartPos = input.readLong(); A'"-m)1P  
nEndPos = input.readLong(); L=7rDW)aa  
} 9)yG.9d1  
input.close(); >x'bZ]gm  
} =[(1my7  
catch(IOException e){e.printStackTrace ();} wR7aQg  
catch(Exception e){e.printStackTrace ();} c d%h
W  
} p~bkf>  

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private void processErrorCode(int nErrorCode) 9p> /?H|  
{ $au2%NL  
System.err.println("Error Code : " + nErrorCode); {of]/3=  
}  0:d
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X
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//停止文件下载 +?e}<#vd'?  
public void siteStop() &LU'.jY  
{ jpO38H0)  
bStop = true; XZ:1!;  
for(int i=0;i<nStartPos.length;i++) YMAQ+A!  
fileSplitterFetch.splitterStop(); ^"tqdeCb=  
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} C.E[6$oVc  
} oO:LG%q  
//负责部分文件的抓取 31 ]7z  
**FileSplitterFetch.java 4Vx+[8W  
*/ uiK:*[  
package NetFox; !Y%D 9  
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import java.io.*; %vc
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import java.net.*; ^W['A]l  
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:GM#&*$2<  
public class FileSplitterFetch extends Thread { *tAqt2{48  
]7F)bIG[  
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String sURL; //File URL q)Je.6$#X  
long nStartPos; //File Snippet Start Position WOH9%xv  
long nEndPos; //File Snippet End Position l%bq2,-%  
int nThreadID; //Thread's ID fNEz  
boolean bDownOver = false; //Downing is over |E|T%i^}./  
boolean bStop = false; //Stop identical /'Bdq?!B&  
FileAccessI fileAccessI = null; //File Access interface /
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException dP3VJ3+ %  
{ d H_2o  
this.sURL = sURL; oUS,+e  
this.nStartPos = nStart; nh|EZp]  
this.nEndPos = nEnd; Spc&X72I  
nThreadID = id; R`7n^,  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 c'lIWuL)  
} 'WzUu MCx  
)]]|d  
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public void run() '5cZzC 2  
{ feg`(R2  
while(nStartPos < nEndPos && !bStop) dp< auA  
{ | /#'S&!U  
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try{ w}b<D#0XC  
URL url = new URL(sURL); GFY-IC+fc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'Ix5,^M}B  
httpConnection.setRequestProperty("User-Agent","NetFox"); g$gVm:=  
String sProperty = "bytes="+nStartPos+"-"; V*kznm  
httpConnection.setRequestProperty("RANGE",sProperty); j%GbgJ  
Utility.log(sProperty); {"\q(R0  
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InputStream input = httpConnection.getInputStream(); YrKFa%k  
//logResponseHead(httpConnection); 5EfY9}dl  
S r[IoF)  
9 G((wiE  
byte[] b = new byte[1024]; z.A4x#>-  
int nRead; k2wBy'M.'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j>V"hf  
{ 5#BF,-Jv  
nStartPos += fileAccessI.write(b,0,nRead); >VypE8H]x  
//if(nThreadID == 1) 2:n|x5\H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F94V5_[  
} [5-!d!a|st  
*\C}Ok=  
0vcET(
 
Utility.log("Thread " + nThreadID + " is over!"); &F86SrsI  
bDownOver = true; *+&z|Pwv[^  
//nPos = fileAccessI.write (b,0,nRead); hxP6C6S  
} w4`!Te  
catch(Exception e){e.printStackTrace ();} `GP3D~  
} 7ia"
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} ]P JH'=  
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fyGCfM  
//打印回应的头信息 *;Ak5.du  
public void logResponseHead(HttpURLConnection con) }1@n(#|c  
{ [6tR&D#K  
for(int i=1;;i++) G@;Nz i89  
{ Sq.9-h%5  
String header=con.getHeaderFieldKey(i); *j/uihY  
if(header!=null) M44_us  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kaV%0Of]  
Utility.log(header+" : "+con.getHeaderField(header)); }t}38%1i  
else M2a}x+5'  
break; %{=4Fa(Jux  
} b,zR5R^D;  
} ;;D% l^m+  
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public void splitterStop() Z<w,UvJa  
{ >_n:_  
bStop = true; rrW! X q  
} !Jh*a *I}  
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} ryz/rf  
]cS&8{ ^2  
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/* =H L9Z  
**FileAccess.java iM4mkCdOO  
*//文件访问(定位，写) 7^`RP e^a+  
package NetFox; YAX #O\,  
import java.io.*; Y#GT*V  
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public class FileAccessI implements Serializable{ 7 _X&5ni  
#tCIuQ,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +k#mvPq  
RandomAccessFile oSavedFile; k0gJ('zah  
long nPos; Vj#%B.#Zbf  
&8R-C[A  
(*LTqC  
public FileAccessI() throws IOException oBhL}r  
{ 6(!,H<bON  
this("",0); GZ;Z  
} <m-Ni  
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public FileAccessI(String sName,long nPos) throws IOException /W7&U =d9  
{ s{b0#[  
oSavedFile = new RandomAccessFile(sName,"rw"); ?*B;514  
this.nPos = nPos; tsCz+MP  
oSavedFile.seek(nPos); clij|?O  
} 8 ))I$+  
Ir'DA_..  
*Cc$eR]-  
public synchronized int write(byte[] b,int nStart,int nLen) O e0KAn  
{ [YL sEo=  
int n = -1; WBIQ%XB'  
try{ (, ;MC/l  
oSavedFile.write(b,nStart,nLen); ][s*~VK;  
n = nLen; >b[4  
} !pE>O-| K  
catch(IOException e) q8&4=eV\A  
{ H620vlC}V  
e.printStackTrace (); D/+@d:-G  
} .&
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return n; Y- z~#;  
} .H*? '*  
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} >KH(nc$  
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/* q[T_*X3o  
**SiteInfoBean.java Th I  
*/ $D0)j(v  
package NetFox; O&gy(  
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6|>"0[4S  
public class SiteInfoBean { si+5h6I.}  
55u^u F  
1tuator  
private String sSiteURL; //Site's URL uWM4O@Qn)d  
private String sFilePath; //Saved File's Path ?w|\7T.?  
private String sFileName; //Saved File's Name URj% J/jD  
private int nSplitter; //Count of Splited Downloading File hfP(N_""S  
VH$\ a~|  
`UzCq06rJ1  
public SiteInfoBean() M[&.kH  
{//nSplitter的缺省值为5 HzFt
 
//default value of nSplitter is 5 exa}dh/uC  
this("","","",5); j[Hg]  
} DVeF(Y3&  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j
:\_*f  
{ =qVAvo'  
sSiteURL= sURL; KJ05Zx~uma  
sFilePath = sPath; Rwi5+;N  
sFileName = sName; <#J<QYF&2  
this.nSplitter = nSpiltter; `zV-1)=  
MXu+I,y*  
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} $$)<(MP3  
.WPuQZ!  
)Uoe~\  
public String getSSiteURL() /Wta$!X{-  
{ pB{ f-M:D  
return sSiteURL; b_"V%
<I  
} |<5J  
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UVvt&=+4  
public void setSSiteURL(String value) _
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{ ZS 7)(j$.  
sSiteURL = value; YpbdScz  
} ,m_&eF  
&Funao>  
,YzC)(-  
public String getSFilePath() :5qqu{GL  
{ e>s.mH6A  
return sFilePath; ^AC+nko*  
} .Jnp{Tet  
3k|~tVM  
PhaQ3%  
public void setSFilePath(String value) %%H. &*i,  
{ itvy[b-*  
sFilePath = value; kk>0XPk  
} ".7
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public String getSFileName() '@1Qx~*]e  
{ 9/^Bj  
return sFileName; H#d! `  
} ^9m^#"ZW`  
.bl/At3A  
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public void setSFileName(String value) -$Z-hxs^  
{ 
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sFileName = value; 5la]l  
} rea}Uq+po  
[&k& $04_  
%PNm7s4x2  
public int getNSplitter() > & lg  
{ %#;(]7Zq  
return nSplitter; " kJWWR  
} -O
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P#'DGW&W0  
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public void setNSplitter(int nCount) ^[,1+WS%  
{ E`LIENm  
nSplitter = nCount; 1=cfk#  
} ^a0-5  
} &|,qsDK(  
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97@?QI}  
/* /$N#_Xblr  
**Utility.java JT+lWhy  
*/ =u1w\>(2Y  
package NetFox; ,)\5O0 D6  
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public class Utility { 'jO-e^qT  
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public Utility() j~<iTLM  
{ 4)S?Y"Bs  
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~$`YzK^*X  
} p!5JO4F$  
OKH~Y-%<  
//线程睡眠 /o3FK  
public static void sleep(int nSecond) y8 u)Q  
{ qSs^}eN  
try{ sA7K ;J})  
Thread.sleep(nSecond); }u$aPS<$!  
} [[Eu?vQ9R  
catch(Exception e) +c2=*IA/  
{ UyfIAC$S  
e.printStackTrace (); ~\(>m=|C:H  
} ~k_zMU-1  
} MnsWB[  
9YsO+7[  
//日志 |
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public static void log(String sMsg) JqhVD@1{  
{ a-A4xL.gm  
System.err.println(sMsg); h]z|OhG  
} )ejqE6'[  
r}M4()9L  
9'r3L)[  
public static void log(int sMsg) ;DWp>jgy  
{ PL2Q!i`[o  
System.err.println(sMsg); OX`GN#yl  
} * =N6_  
} xRZT
 
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/* {Q3#]Vu  
**TestMethod.java wAwH8xLU  
*/ i3!$M/_]  
package NetFox; ?At-   
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L&k$4,Z9  
public class TestMethod { }U1{&4Ph  
WmBnc#>gK  
 x a,LV  
public TestMethod() ?B4QTx9B  
{ ///xx/weblogic60b2_win.exe /9^0YC;Y*  
try{ N.cRZm%  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); WK5bt2x  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); EjC
s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); U.9nHo{  
fileFetch.start(); ~a|Q[tiV]  
} yKy)fn!  
catch(Exception e){e.printStackTrace ();} {.)~4.LhQM  
545xs`Q_  
~}l,H:jk@  
} G#M]\)f%  
VL1z$<vVXt  
@"5u~o')@v  
public static void main(String[] args) WYUU-  
{ s8O+&^(U  
new TestMethod(); ,;& PKY  
} q.tL'  
} gVWLY;c 3}  
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