http断点续传简单实现（java)

/* UxxX8N  
**SiteFileFetch.java f@gvDo]Y  
*/ T^F83Py<  
package NetFox; {1_<\~J  
import java.io.*; +/bD9x1H  
import java.net.*; )~Gn7  
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public class SiteFileFetch extends Thread { sjOv!|]A  
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SiteInfoBean siteInfoBean = null; //文件信息Bean puLgc$?  
long[] nStartPos; //开始位置 %ZcS"/gf  
long[] nEndPos; //结束位置 QJ(5o7Tfn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @q`T#vd  
long nFileLength; //文件长度  +hKs  
boolean bFirst = true; //是否第一次取文件 Y9gw ('\w  
boolean bStop = false; //停止标志 XUKlgl!+.  
File tmpFile; //文件下载的临时信息 as'yYn8  
DataOutputStream output; //输出到文件的输出流 93Zij<bH?e  
p_ f<@WE  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） PxQQfI>  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7#W]
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{ &2U%/JqY  
siteInfoBean = bean; h@Jg9AM  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yj@k0TWT$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `qYii
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if(tmpFile.exists ()) vcsSi%M\U  
{ 4lWqQVx  
bFirst = false; 1C<d^D_!p  
read_nPos(); KK
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} {%CW!Rc
 
else MPDRMGR@i  
{ &F/-%l!  
nStartPos = new long[bean.getNSplitter()]; /a<UKh:A[  
nEndPos = new long[bean.getNSplitter()]; IC5QH<.$C  
} 'l=>H#}<B  
(# mvDz  
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} Ws7fWK;  
:o~'\:/  
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public void run() Il9xNVos#  
{  
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//获得文件长度 sT"IC
ooc  
//分割文件 w|]Tt="   
//实例FileSplitterFetch }<X*:%#b  
//启动FileSplitterFetch线程 l`N4P  
//等待子线程返回 !L8q]]'XM  
try{ /FE+WA}r  
if(bFirst) A_\Jb}J1<  
{ ['Lo8 [  
nFileLength = getFileSize(); dQ7ii
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if(nFileLength == -1) f|M^UHt8*  
{ ?gUraS
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System.err.println("File Length is not known!"); Z^2SG
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} [ i,[^  
else if(nFileLength == -2) LdH1sHy*d`  
{ g%"SAeG<K  
System.err.println("File is not access!"); i9zh X1#  
} ZP!.C&O  
else JZ`SV}\`  
{ (J%4}Dm  
for(int i=0;i<nStartPos.length;i++) #7Q9^rG  
{ ']eN4H&=?}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :0Jn`Ds4o  
} 'DVn /3?X  
for(int i=0;i<nEndPos.length-1;i++) (kB  
{ oNe:<YT  
nEndPos = nStartPos[i+1]; B G\)B  
} %;ED}X  
nEndPos[nEndPos.length-1] = nFileLength; T@.+bD  
} e
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} s=-?kcoJ2d  
PdVx&BL*  
{22ey`@`h  
//启动子线程 B=K<k+{6"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #K:iB*  
for(int i=0;i<nStartPos.length;i++) -XL
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{ g2TK(S|#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kVM*[<k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 72xf|s=  
nStartPos,nEndPos,i); {'A
15  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }NwmZw>_  
fileSplitterFetch.start(); NAE|iyw  
} 75^*4[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ";(m,if-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @w==*.x  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "?6*W"N9  
nEndPos = " + nFileLength); V.u^;gr3  
// fileSplitterFetch[nPos.length-1].start(); 0 fT*O  
KYB3n85 1  
hr.mzQd  
//等待子线程结束 6zU0 8z0-  
//int count = 0; 2N &B  
//是否结束while循环 @(a~p  
boolean breakWhile = false; dfVI*5[Z  

$aTo9{M^  
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while(!bStop) 7YTO{E6]d\  
{ Om:Gun\%  
write_nPos(); oSMIWwg7G  
Utility.sleep(500); K[noW  
breakWhile = true; LL3| U  
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for(int i=0;i<nStartPos.length;i++) ?P7QAolrr  
{ u]
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if(!fileSplitterFetch.bDownOver) fvTp9T\f3  
{ 6tVp%@  
breakWhile = false; Gv)*[7  
break; O>rz+8T  
} DP*V|)  
} ,bzgjw+R5  
if(breakWhile) uKIR$n"  
break; I %1P:-  
-t`KCf,0  
GF<SQHL,  
//count++; 25xt*30M  
//if(count>4) bsc b
 
// siteStop(); ezJ^ r,D|  
} V^G+_#@,,  
**9[e[(X  
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System.err.println("文件下载结束！"); gY-}!9kW]  
} S
|RUc}(  
catch(Exception e){e.printStackTrace ();} \@6w;tyi  
} 0[Zs8oRiI  
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'OYnLz`"6  
//获得文件长度 .0y .0=l  
public long getFileSize() Z79Y$d>G<E  
{ <m`Os2#  
int nFileLength = -1; tN;~.\TKg  
try{ J72kjj&C  
URL url = new URL(siteInfoBean.getSSiteURL()); uhmSp+%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '! ;Xxe5  
httpConnection.setRequestProperty("User-Agent","NetFox"); $kQQdF  
vN)l3  
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int responseCode=httpConnection.getResponseCode(); 60p*4>^v  
if(responseCode>=400) 5=_))v<Tp  
{ ZoKXao  
processErrorCode(responseCode); r$d'[ZcX  
return -2; //-2 represent access is error %Zu+=IZ  
} SC0_ h(zb,  
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=G/`r!r*0I  
String sHeader; tj!~7lo  
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1FEY&rpR  
for(int i=1;;i++) XM*%n8q7#N  
{ !RdubM  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); G?{uR6s>#  
//Utility.log(in.readLine()); PHn3f;I  
sHeader=httpConnection.getHeaderFieldKey(i); Rwz (20n\^  
if(sHeader!=null) a s?)6  
{ IY9##&c3>  
if(sHeader.equals("Content-Length")) 9"k^:}8.  
{ wd~!j&`a  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); yB^_dE  
break; Z0%Qy+%  
} m3K .\3  
} {d,~=s0T  
else 0j|JyS:}G  
break; ?qjlWCV|e  
} m:XMF)tW  
} -}*YfwK  
catch(IOException e){e.printStackTrace ();} a)Ca:p  
catch(Exception e){e.printStackTrace ();} "@)9$-g  
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Utility.log(nFileLength); okZDxg`6  
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return nFileLength; :CAbGs:56  
} Od:,r  
,] ,dOIOwn  
|cE 69UFB  
//保存下载信息（文件指针位置） 9nPc>O$  
private void write_nPos() PKM8MYvo  
{ mN:p=.& <  
try{ r/vRaOg>X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @eGJ_
J  
output.writeInt(nStartPos.length); g4 |s9RMD  
for(int i=0;i<nStartPos.length;i++) .-g++f(_i  
{ xui.63/  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); <X_I`  
output.writeLong(fileSplitterFetch.nEndPos); le-Q&*
  
} u/BCl!`  
output.close(); ,1+)qv#|i  
} 2Y@:Vgg  
catch(IOException e){e.printStackTrace ();} q-fxs8+m|  
catch(Exception e){e.printStackTrace ();} !5P\5WF~Y  
} q^_PR|  
_8CE|<Cn  
?p8(Uc#73  
//读取保存的下载信息（文件指针位置） ,5_Hen=PI  
private void read_nPos() 5:ZM-kZT  
{ *L3>:],7  
try{ Ty21-0F  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -&u2C}4s  
int nCount = input.readInt(); yqm^4)Dp  
nStartPos = new long[nCount]; 8)D5loS  
nEndPos = new long[nCount]; .*N,x0B(  
for(int i=0;i<nStartPos.length;i++) SWYIQ7*  
{ m\88Etl@  
nStartPos = input.readLong(); EVW{!\8[  
nEndPos = input.readLong(); _BV'J92.  
} ^nYS@  
input.close(); u2SnL$A7  
} ix<sorR H  
catch(IOException e){e.printStackTrace ();} Q}a 1P8?S  
catch(Exception e){e.printStackTrace ();} ,&;#$ b5  
} ~L G).  
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@"9^U_Qf1z  
private void processErrorCode(int nErrorCode) #4ZDY,>Xi#  
{ "0F =txduS  
System.err.println("Error Code : " + nErrorCode); R)AFaP |  
} lH6z
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!}D!_z,)u  
>g!a\=-[  
//停止文件下载 <|_/i/H  
public void siteStop() #-ioLt%  
{ :h1-i  
bStop = true; sD,[,6(  
for(int i=0;i<nStartPos.length;i++) -vcHSwGb  
fileSplitterFetch.splitterStop(); 2t3'"8xJ  
-0 [^w  
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} .u3!%{/v(c  
} !\Y85o>JU  
//负责部分文件的抓取 pm+_s]s,  
**FileSplitterFetch.java 4#$~gTc@  
*/ m L#-U)?F  
package NetFox; sjpcz4|K  
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import java.io.*; c}a.  
import java.net.*; .]+oE$,!  
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public class FileSplitterFetch extends Thread { sgdxr!1?y  
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String sURL; //File URL !Pf_he  
long nStartPos; //File Snippet Start Position ;iJ*.wVq  
long nEndPos; //File Snippet End Position G992{B  
int nThreadID; //Thread's ID CA7ZoMB#  
boolean bDownOver = false; //Downing is over nPp\IE}:  
boolean bStop = false; //Stop identical :-B,Q3d  
FileAccessI fileAccessI = null; //File Access interface C%ibIcm y  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?{W@TY@S  
{ jM8e2z3  
this.sURL = sURL; " (c#H  
this.nStartPos = nStart; 6eSc
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this.nEndPos = nEnd; Fp>iwdjFg  
nThreadID = id; %xtTh]s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 V)M+dhl  
} E5D5  
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public void run() 1Zc1CUMG  
{ [5 Mt,skC:  
while(nStartPos < nEndPos && !bStop) 6/`$Y!.ub  
{ X{A|{u=  
:_;9&[H9ha  
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try{ cn&\q.!fh  
URL url = new URL(sURL); H!Gsu$C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vzl+0"  
httpConnection.setRequestProperty("User-Agent","NetFox"); QXZjsa_|  
String sProperty = "bytes="+nStartPos+"-"; ?N2/;u>  
httpConnection.setRequestProperty("RANGE",sProperty); 4fPbwiKj  
Utility.log(sProperty); *-~B{2b<  
KI
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InputStream input = httpConnection.getInputStream(); &WN#HI."]  
//logResponseHead(httpConnection); x<#Z3Kla  
?4%'6R  
[t@  
byte[] b = new byte[1024]; <rd7<@>5D  
int nRead; @!z9.o;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1"J\iwN3  
{ LB}y,-vX>  
nStartPos += fileAccessI.write(b,0,nRead); _:ypPRJ  
//if(nThreadID == 1) 2 2K:[K  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ei!5Qya>  
} AfmGA9  
44T>Yp09  
V?U->0>Z4  
Utility.log("Thread " + nThreadID + " is over!"); $ 2'AY  
bDownOver = true; '`g#Zo  
//nPos = fileAccessI.write (b,0,nRead); e%#(:L  
} j)IXe 0dMC  
catch(Exception e){e.printStackTrace ();} b#%s!  
} (
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} /Po't(-x  
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L~N<<8?\   
//打印回应的头信息 Dohq@+] O  
public void logResponseHead(HttpURLConnection con) <eRE;8C-  
{ My'u('Q%  
for(int i=1;;i++) .kWMr^ g  
{ jbx@ty  
String header=con.getHeaderFieldKey(i); K5-wuD1  
if(header!=null) bDI#'F  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /mLOh2T  
Utility.log(header+" : "+con.getHeaderField(header)); Y<%)Im6v/  
else 7\*_/[
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break; HO,z[6  
} ^CZ!rOSv  
} C?6wIdp  
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public void splitterStop() ZuIr=`"j  
{ le%&r  
bStop = true; 7UQFAt_r  
}  QDCu  
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} {+~}iF<%  
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~#/NpKHT@A  
/* ">='l9  
**FileAccess.java QkbXm[K.Z  
*//文件访问(定位，写) )cnH %6X  
package NetFox; Fd@n#DR `  
import java.io.*; P]]re,&R  
6Y4sv5G  
vmW >$P  
public class FileAccessI implements Serializable{ x6Q,$B  
];& @T\Rj  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 'Fi\Qk'D@  
RandomAccessFile oSavedFile; C3EQzr`  
long nPos; ;hP43Bi  
$yG>=GN  
;Fw{p{7<  
public FileAccessI() throws IOException *?sdWRbu}l  
{ %j3XoRex><  
this("",0); cXM4+pa=%  
} ~qFuS933  
:x"Q[079  
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public FileAccessI(String sName,long nPos) throws IOException J1P jM
b}  
{ ^0oOiZs  
oSavedFile = new RandomAccessFile(sName,"rw"); P)7:G?OTx  
this.nPos = nPos; Mr/;$O{  
oSavedFile.seek(nPos); QD6<sw@]P  
} u-v/`F2wN  
4%k{vo5i  
AlZ]UGf^  
public synchronized int write(byte[] b,int nStart,int nLen) nPlg5&E  
{ )4h4ql W  
int n = -1; jVA|Vi_2  
try{
?@n, 9!  
oSavedFile.write(b,nStart,nLen); Ife/:v  
n = nLen; [wp(s2=  
} |HT5G=dw
 
catch(IOException e) ]7+9>V  
{ "{TVd>9_  
e.printStackTrace (); ](%EQ[  
} -@=As00Bg  
BqoGHg4iq  
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return n; X ? eCK,  
} 6*W7I-A  
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,> %=,x
 
} _tba:a(  
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/* H\r- ;,&  
**SiteInfoBean.java OSu/!Iv\  
*/ 3UR'*5|'  
package NetFox; B>]4NF\)H9  
:{8,O-  
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public class SiteInfoBean { ?^} z  
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IjaFNZZC!  
private String sSiteURL; //Site's URL 5MX7V4ist  
private String sFilePath; //Saved File's Path =Z 
/*  
private String sFileName; //Saved File's Name $j(laD#AR  
private int nSplitter; //Count of Splited Downloading File Xtk3~@  
&x"hM  
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public SiteInfoBean() eeVzOq(  
{//nSplitter的缺省值为5 j|-{*t{/x  
//default value of nSplitter is 5 5K#<VU*:  
this("","","",5); R+&{lc  
} ]H-5   
prw% )#,  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !n^7&Y[N;  
{ vp|.x |@  
sSiteURL= sURL; x'iBEm  
sFilePath = sPath; E51'TT9  
sFileName = sName; $?*XPzZ  
this.nSplitter = nSpiltter; "2_nN]%u-  
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}  [1Q:  
=a$7^
d  
6[T)Q^0`  
public String getSSiteURL() ?mbI6fYv  
{ cv7.=*Kb;  
return sSiteURL; #,S0uA  
} ? 4v"y@v  
0f;`Zj0l8  
Hd ${I",  
public void setSSiteURL(String value) LL%s$>c65A  
{ WqRaD=R->;  
sSiteURL = value; s*tzU.E(  
} e
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)U+Pt98"  
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public String getSFilePath() yP"D~u  
{ _zG[b/:p  
return sFilePath; 1#V&'A  
} XQStlUw8+  
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public void setSFilePath(String value) ^$;5ZkQy  
{ =SK{|fBB  
sFilePath = value; YPmgR]=6  
} `{+aJ0<S  
"%dok@v  
/_ RrNzqy  
public String getSFileName() v"V?  
{ zuYz"-(L  
return sFileName; osPrr QoH  
} yL"pzD`[H  
]-8yZWal  
nA.~}  
public void setSFileName(String value) *GC9o/  
{ c.Do b?5  
sFileName = value; !3Ed0h]Bfa  
} 9UcSQ"D  
#RTiWD[o  
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public int getNSplitter() cE7IHQ  
{ }
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return nSplitter; (E<QA  
} 9Fh1rZD<  
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`t Zw(Z=h  
public void setNSplitter(int nCount) zf?U q  
{ wKj0vMW  
nSplitter = nCount; V"W)u#4,  
} DtOL=m]s  
} xYD.j~  
#]e](j>]  
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/*
'/
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**Utility.java FW,@.CX  
*/ |<w Z;d  
package NetFox; Z >F5rkJ  
8L,i}hIo.  
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public class Utility { ?%wM8
?  
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public Utility() }@NT#hD  
{ TI^M9;b  
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[cvtF(,  
} '(&,i/O  
}q<%![%  
//线程睡眠 D$PR<>=y  
public static void sleep(int nSecond)
qFg"!w  
{ iVqa0Gl+}  
try{ Yn1CU  
Thread.sleep(nSecond); 23JuuV.  
} ZX03FJL7u  
catch(Exception e) .qG*$W2f  
{ @T8$/  
e.printStackTrace (); z9IJ%=R  
} IiRII)  
} o7WK"E!pF'  
bsgrg  
//日志 (N`x  
public static void log(String sMsg) (&ABfm/t  
{ Nw|m"VLb  
System.err.println(sMsg); s2M|ni=  
} Ri&?uCCM  
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g  
public static void log(int sMsg) 268H!'!\  
{ RmcQGQ
 
System.err.println(sMsg); zMW[Xx!  
} hY-;Vh0J  
} a54qv^IS  
OJ Y_u[  
cp\A xWtUZ  
/* [!CIBK99  
**TestMethod.java E]26a,^L  
*/ !mLD`62.  
package NetFox; f0,,<ib.w
 
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public class TestMethod { {^qp
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FELTmQUV  
public TestMethod() PK7 kpC  
{ ///xx/weblogic60b2_win.exe Z UCz-53  
try{ 4:S?m(ah/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5gnmRd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Wu9))Ir  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 
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fileFetch.start(); ddiBjp2.!  
} jaq`A'o5  
catch(Exception e){e.printStackTrace ();} y8QJ=v* B  
%Yi^{ZrM  
:?.RZKXQF  
} j(SBpM  
PWw2;3`-6w  
3]u[NR  
public static void main(String[] args) 0p;pTc  
{ "X7;^yY  
new TestMethod(); C0bOPn  
} Im*~6[  
} !33)6*s  
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