http断点续传简单实现（java)

/* 0Ui_Trlc  
**SiteFileFetch.java jQ%1lQ#R)  
*/ <PuY"-`/Oc  
package NetFox; Q<;EQb#  
import java.io.*; 'PY;  
import java.net.*; ?QJx!'Y,p  
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public class SiteFileFetch extends Thread { rOt{bh6r  
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SiteInfoBean siteInfoBean = null; //文件信息Bean (@xC-
*  
long[] nStartPos; //开始位置 ?hc=w2Ci  
long[] nEndPos; //结束位置 vfv?QjR  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~/-SKGzo-  
long nFileLength; //文件长度 ;nW;M 4{  
boolean bFirst = true; //是否第一次取文件 R3lZ|rxv:  
boolean bStop = false; //停止标志 JQ0Z%;"  
File tmpFile; //文件下载的临时信息 LTo!DUi
`  
DataOutputStream output; //输出到文件的输出流 U+ik& R#  
xt pY*  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1v.#ndk  
public SiteFileFetch(SiteInfoBean bean) throws IOException YtSYe%  
{ 2\k!DF  
siteInfoBean = bean; \y=28KKc:c  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); zNrn|(Y%Y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Q5Nbu90  
if(tmpFile.exists ()) 3!gz^[!?EN  
{ #t(/wa4  
bFirst = false; JU^Y27  
read_nPos(); VV/T)qEe7>  
} /4pYhJ8S  
else lqL5V"2Y  
{  ArAe=m!u  
nStartPos = new long[bean.getNSplitter()]; JvW7h(u7g  
nEndPos = new long[bean.getNSplitter()]; #xu1 eX0<  
} BF gxa#De  
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} 2ns,q0I A  
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public void run() E Zf|>^N  
{ e4Y+u8gT  
//获得文件长度 Bl6I@w  
//分割文件 )r
j!/%  
//实例FileSplitterFetch [u K,.G  
//启动FileSplitterFetch线程 [9Rh"H;h  
//等待子线程返回 Y_ne?/sZE  
try{ t855|  
if(bFirst) VgYy7\?p  
{ iZdl0;16[  
nFileLength = getFileSize(); YB4 ZI  
if(nFileLength == -1)  gvo98Id  
{ Ji!i}UjD7!  
System.err.println("File Length is not known!"); (EWGX |QA  
} eF{uWus  
else if(nFileLength == -2) ZZ^A&%E(a  
{ E8sM`2z5  
System.err.println("File is not access!"); ~Uv#)  
} ;ZI8vFb  
else n5A|Zjk;  
{ Vfy@?x= &  
for(int i=0;i<nStartPos.length;i++) gE@Pb  
{ &0Y |pY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Eb9h9sjv  
} ;k#_/c  
for(int i=0;i<nEndPos.length-1;i++) ",gVo\^  
{ 7lwI]/ZH*  
nEndPos = nStartPos[i+1]; V*te8HIe  
} iH-,l  
nEndPos[nEndPos.length-1] = nFileLength; LXby(|<j  
} <#M1I!R  
} k CGb~+  
^znUf4N1  
420K6[  
//启动子线程 Pz2Q]}(w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jA:'P~`Hj  
for(int i=0;i<nStartPos.length;i++) CXoiA"P  
{ 6vNn;-gg.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3 I%N4K4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), DUu:et&c1  
nStartPos,nEndPos,i); B!quj!A  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zJ8T.+qJ  
fileSplitterFetch.start(); Z P|k3   
} 3)=ix. wW  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H'!OEZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); F^Jz   
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *(r9c(xa  
nEndPos = " + nFileLength); 7)#JrpTj%  
// fileSplitterFetch[nPos.length-1].start(); 5D7 L)>  
}eZ\~2  
r 56~s5A  
//等待子线程结束 9$X" D  
//int count = 0; &${| o@  
//是否结束while循环 T^7}Qs9  
boolean breakWhile = false; h2mHbe43  
>+i+_^]  
5 8;OTDR!  
while(!bStop) "\;n t5L  
{ *< fJgc"3  
write_nPos(); kP(
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/  
Utility.sleep(500); 4PS|  
breakWhile = true; &DYC3*)Jih  
l> H'PP~  
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for(int i=0;i<nStartPos.length;i++) [=cbzmX[  
{ yCkc3s|DA;  
if(!fileSplitterFetch.bDownOver) oM@%2M_O(  
{ a[zVC)N0  
breakWhile = false; Txe*$T,(  
break; kl1Q:  
} SufM~9Ll  
} jb/C\2U4)  
if(breakWhile)
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break; !JDuVqW  
qPDRB.K|}  
d?YSVmG  
//count++; 751Qi  
//if(count>4) UL~~J[1r  
// siteStop(); nZNS}|6  
} tNZZCdB  
<Mo{o2F=  
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System.err.println("文件下载结束！"); ~LFM,@  
} L*6<h  
catch(Exception e){e.printStackTrace ();} ^P [#
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} A`(C
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//获得文件长度 @*6_Rp"@  
public long getFileSize() o^d|/;  
{ }NV<k
 
int nFileLength = -1; zU0JwZi  
try{ SV95
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URL url = new URL(siteInfoBean.getSSiteURL()); Um`KmM3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ik5-ooZ&{  
httpConnection.setRequestProperty("User-Agent","NetFox"); a.O"I3{?h  
(<OmYnm  
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int responseCode=httpConnection.getResponseCode(); I-J%yutB  
if(responseCode>=400) ?0z/i^I  
{ M,{;xf  
processErrorCode(responseCode); 0$yHO2 f  
return -2; //-2 represent access is error Ae^4  
} =7:}/&  
hlc g[Qdo*  
fyx Q{J  
String sHeader; NX;{L#lQ  
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for(int i=1;;i++) Ut1s~b1  
{ MD4mh2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]5ibg"{S  
//Utility.log(in.readLine()); T# tFzbr  
sHeader=httpConnection.getHeaderFieldKey(i); /d}5R@Oy  
if(sHeader!=null) hO
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{ Rdd9JJsVd  
if(sHeader.equals("Content-Length")) [%Dh0hOg  
{ Bz:Hp{7&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d|UH AX  
break; 8)
`  
} b-c6.aKf|  
} h"2^` )!u  
else JiA1yt  
break; \ sz
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} s1%2({wP  
} [P)](8nR[  
catch(IOException e){e.printStackTrace ();} 5*B'e{C  
catch(Exception e){e.printStackTrace ();} ^ 6t"A  
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Utility.log(nFileLength); "4*QA0As  
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return nFileLength; .Z17X_  
} +@@( C9  
5':j=KQE_  
h=NXU9n%'  
//保存下载信息（文件指针位置） 4d
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private void write_nPos() 6,R<8a;Wn  
{ >Ij#+=  
try{ l,b_'
m@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); t#]VR7]  
output.writeInt(nStartPos.length); +$^[r  
for(int i=0;i<nStartPos.length;i++) [R~@#I P!  
{ Fk`6 q
 
// output.writeLong(nPos); :}v:=ck  
output.writeLong(fileSplitterFetch.nStartPos); c Ct5m  
output.writeLong(fileSplitterFetch.nEndPos); "(+aWvb  
} GsqO^SV  
output.close(); $VxuaOTyVZ  
} ]HG>Og  
catch(IOException e){e.printStackTrace ();} MAc/ T.[  
catch(Exception e){e.printStackTrace ();} ~~ty9;KYL  
} ^M1O)   
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//读取保存的下载信息（文件指针位置） itO1ROmu  
private void read_nPos() sQT,@+JEr  
{ %Si3LQf  
try{ Q6[h;lzGV  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K~8!Gh{h]  
int nCount = input.readInt(); 1<M~
#  
nStartPos = new long[nCount]; MY&?*pV)  
nEndPos = new long[nCount]; z7*mT}Q  
for(int i=0;i<nStartPos.length;i++) \]L ha  
{ ,#.^2O9-^  
nStartPos = input.readLong(); 3ZYrNul"  
nEndPos = input.readLong(); rV I-Yb  
} m{6*ae  
input.close(); /-3)^R2H  
} .Ag)/Xm(?  
catch(IOException e){e.printStackTrace ();} Vf(n  
catch(Exception e){e.printStackTrace ();} @d[)i,d:G  
} XToYtdt2  
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private void processErrorCode(int nErrorCode) D4+OWbf6  
{ [rhK2fr:i  
System.err.println("Error Code : " + nErrorCode); vRO`hGH  
} V4%7
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4-xg+*()  
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//停止文件下载 M""X_~&I"  
public void siteStop() 79M`?xm  
{ y;LZX-Z-  
bStop = true; ?kc,}/4  
for(int i=0;i<nStartPos.length;i++) A^
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fileSplitterFetch.splitterStop(); VDv>I 2%  
m] IN-'  
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} gf|&u
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} 3],[6%w  
//负责部分文件的抓取 2FTJxSC  
**FileSplitterFetch.java $D#eD.  
*/ )$FwB6^  
package NetFox; gO!:WD  
*wz62p  
#!M;4~Sfx  
import java.io.*; fAeq(tI=  
import java.net.*; mz .uK2l{  
ob=IaZ@?  
9KZLlEk5O  
public class FileSplitterFetch extends Thread { g*:f#u5  
e&="5.ik  
_&F*4t!n_  
String sURL; //File URL 6q^.Pg-Y  
long nStartPos; //File Snippet Start Position If.h
A}  
long nEndPos; //File Snippet End Position cz*Z/5XH  
int nThreadID; //Thread's ID WAh{*$Rpl  
boolean bDownOver = false; //Downing is over *s"{JrG`O  
boolean bStop = false; //Stop identical <F5x}i~(C  
FileAccessI fileAccessI = null; //File Access interface &#[6a&9#[A  
k%ckV`y  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException rIF6^?  
{ *ps")?tlC  
this.sURL = sURL; s$OnQc2/  
this.nStartPos = nStart; \Ot,&Z k2  
this.nEndPos = nEnd; p< jM%fbZk  
nThreadID = id; ais"xm
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 [,p[%Dza  
} {= l9{K`~  
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public void run() h{M.+I$}C  
{ e?!A]2  
while(nStartPos < nEndPos && !bStop) 9.$k^|~  
{ XhJbBVS|  
/*{s1Zcb  
 |<1  
try{ WJ$!W  
URL url = new URL(sURL); ukRbSJ5a5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "EC,#$e%ev  
httpConnection.setRequestProperty("User-Agent","NetFox"); rQPV@J]:  
String sProperty = "bytes="+nStartPos+"-"; djtCv;z  
httpConnection.setRequestProperty("RANGE",sProperty); F:rT.n  
Utility.log(sProperty); c4n]#((%a  
?i7}d@636  
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InputStream input = httpConnection.getInputStream(); PWThm ooP  
//logResponseHead(httpConnection); iOzY8M+N(  
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byte[] b = new byte[1024]; yGtGhP8  
int nRead; =;^#5dpt$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Zo|# ,AdE>  
{ 3]}wZY0  
nStartPos += fileAccessI.write(b,0,nRead); Kr|9??`0E  
//if(nThreadID == 1) Zb=H\#T  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Vi1= E])  
} 3]1uDgfr  
WfE,U=e*  
I='S).  
Utility.log("Thread " + nThreadID + " is over!"); |/-H:\5  
bDownOver = true; zDO`w0N  
//nPos = fileAccessI.write (b,0,nRead); WrNm:
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} +\n8##oAI  
catch(Exception e){e.printStackTrace ();} d'Z  
} 7R`:^}'>  
} fPW(hb;  
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_+hf.[""  
//打印回应的头信息 (:]on
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public void logResponseHead(HttpURLConnection con) jN43vHm\Y9  
{ 7Z+4F=2ff  
for(int i=1;;i++) m.A_u7D@  
{ +WYXj  
String header=con.getHeaderFieldKey(i); [vs5e3B)  
if(header!=null) `Al( AT(p  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0R%R2p'wG  
Utility.log(header+" : "+con.getHeaderField(header)); "eiZZSz  
else %;|^*?!J0  
break; B&E qd  
} h{&}p-X&[  
} qZ6Mk9@M  
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public void splitterStop() =)GhrWeVi4  
{ m:,S1V_jl  
bStop = true; t Tky  
} ErNL^Se1  
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b xT
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} IPE2t  
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/* QFm~wv8:  
**FileAccess.java q;p:)Q"  
*//文件访问(定位，写) VnB"0"%w  
package NetFox; b]Xc5Dp{  
import java.io.*; ,dM}B-  
7]w]i5  
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public class FileAccessI implements Serializable{ `|\z#Et  
;LM,<QJ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7LM?<lp]  
RandomAccessFile oSavedFile; `$*cW1  
long nPos; h`0'27\C  
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public FileAccessI() throws IOException %\5d?;  
{ {uQp
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this("",0); i,DnXgmz@  
} k<09
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public FileAccessI(String sName,long nPos) throws IOException B1GBQH$Ms  
{ GoK[tjb  
oSavedFile = new RandomAccessFile(sName,"rw"); ]YP J.[n  
this.nPos = nPos; O|opNr  
oSavedFile.seek(nPos); M7|k"izv  
} i1"4ztZ  
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public synchronized int write(byte[] b,int nStart,int nLen) &"(xd@V)]A  
{ u!FX 0Ip  
int n = -1; 2aef[T
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try{ Ov$_Phm:  
oSavedFile.write(b,nStart,nLen); lC8DhRd0_  
n = nLen; 6^M!p4$hF  
} 2cy: l03  
catch(IOException e) s%K9;(RWI  
{ }i7Gv K<[:  
e.printStackTrace (); y my/`%  
} z3V[ Vi  
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return n; &QaFX,N"  
} Cx.GEY|0  
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} 'gDhi!h%  

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/* LZirw'  
**SiteInfoBean.java YY\$lM  
*/ [ &cCE   
package NetFox; WJp9io[GM  
2m]CmdV^  
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public class SiteInfoBean { &R? \q*  
}pOem}  
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private String sSiteURL; //Site's URL T)ZO+}  
private String sFilePath; //Saved File's Path sYQ=nL  
private String sFileName; //Saved File's Name u|v2J/
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private int nSplitter; //Count of Splited Downloading File Ifghyh<d  
Rt &Oz!TQ  
E;Akm':  
public SiteInfoBean() zGfF.q}  
{//nSplitter的缺省值为5 ^W&qTSjh  
//default value of nSplitter is 5 9~ [Sio~  
this("","","",5); >}& :y{z~  
} 3ZZ"mlk*  
'jr\F2  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) I\%a<  
{ S?ypka"L  
sSiteURL= sURL; '&XL|_Iq  
sFilePath = sPath; w}wABO  
sFileName = sName; Y8c#"vm(  
this.nSplitter = nSpiltter; WInfn f+'  
:qfP>Ok  
UMcQqV+vT  
} 8F?6Aq1B  
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public String getSSiteURL() ~N<zv({lG  
{ 5crd.1@^  
return sSiteURL; 0X.(BRI~6p  
} eXB'>#&s  
?
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public void setSSiteURL(String value) 2pKkg>/S  
{ G?p !*7N  
sSiteURL = value; p_^Jr*Mv  
} =;hz,+  
?pE)K<+Zkf  
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public String getSFilePath() m?Tv8-1  
{ C`4m#  
return sFilePath; %rU8^'Gu  
} ;\[n{<   
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ZDQc_{e{  
public void setSFilePath(String value) |"j{!Ei  
{ S.u1[Yz^  
sFilePath = value; F$tshe(  
} Ol%KXq[  
TBAF_$  
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public String getSFileName() I&m C  
{ ~AqFLv/%  
return sFileName; [&Yrnkgr  
} IE^xk@  
'AU:[eyUV  
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public void setSFileName(String value) /0.m|Th'm  
{ A_:CGtv:  
sFileName = value; Mm&#I[:  
} ECZ`I Z.  
$N;Nvp2  
<$"  
public int getNSplitter() U]o  
{ zJ"`40V*;  
return nSplitter; U=kPxe  
} e7n[NVrX  
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r
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public void setNSplitter(int nCount) d[0
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{ i[IOR0  
nSplitter = nCount; E.Vlz^B  
} *Y:;fl +v  
} -o+<m4he  
jDWmI%Y.  
{IB}g:  
/* zs=[C+Z\  
**Utility.java [>IV#6$  
*/ '<Fr}Cn  
package NetFox; !_yWe  
e&R?9z-*  
S)?V;@p6  
public class Utility { G!G]*p5  
lG1\41ZxB  
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public Utility() 5YZh e4R  
{ Q\QSnMM&]  
*F^t)K2  
wr) \G
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} iImy"$yX{  
SsY:gp_  
//线程睡眠 a3f-9LN  
public static void sleep(int nSecond) hw @)W  
{ (D<_ iV
 
try{ |ee A>z"I  
Thread.sleep(nSecond); J,W<vrKOcN  
} l_2B  
catch(Exception e) nT:F{2 M;  
{ ^uV=|1<%  
e.printStackTrace (); ITt*TuS2c  
} ]jB`"to*}  
} z]49dCN  
I(5sKU3<  
//日志 B7 #O>a  
public static void log(String sMsg)
Y\ C"3+I  
{ qexnsL  
System.err.println(sMsg); _{ Np_(g  
} J4woZ{d  
+~7x+6E  
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public static void log(int sMsg) "Dt: 8Nf^  
{ Q"Pl)Q\  
System.err.println(sMsg); x@p1(V.  
} u]766<Z  
} ]YciLc(  
{0o,2]o!:  
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/* /a .XWfu  
**TestMethod.java v;WfcpWq2  
*/ {hH8+4c7  
package NetFox; B>kVJK`X  
!r#36kO  
f;`7}7C  
public class TestMethod { 2Kmnt(>  
riu_^!"Z_  
~p!=w#/  
public TestMethod() !^x;4@Ejm  
{ ///xx/weblogic60b2_win.exe d(_;@%p1X  
try{ j9d^8)O,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 03?7kAI  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c!ul9Cw  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1G}\IK1+  
fileFetch.start(); x,fX mgE  
} @TraEBJGL  
catch(Exception e){e.printStackTrace ();} j9r%OZw{  
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2)\gIMt%  
} u$Wv*;TT%  
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public static void main(String[] args) cl{kCSZo.z  
{ IQ $/|b/  
new TestMethod(); }? :T*CJ  
} g@Z7f y7  
} T!2gOe  
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