http断点续传简单实现（java)

/* O_&Km[  
**SiteFileFetch.java ?I 7hbqQd  
*/ C oO0~q  
package NetFox; Ml+O - 3T  
import java.io.*; Ce_l\J8G  
import java.net.*; <s5s<q2  
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public class SiteFileFetch extends Thread { qa5 T(
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SiteInfoBean siteInfoBean = null; //文件信息Bean 4z,n:>oH  
long[] nStartPos; //开始位置 +qmV|$rmM  
long[] nEndPos; //结束位置 vtXZ`[D,l)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 YJBf~0r  
long nFileLength; //文件长度 mA6Nmq%{ F  
boolean bFirst = true; //是否第一次取文件 LS4E.Xdn  
boolean bStop = false; //停止标志 .Yxf0y?uv  
File tmpFile; //文件下载的临时信息 $e,'<Jl  
DataOutputStream output; //输出到文件的输出流 $%5!CD1)  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） # |,c3$  
public SiteFileFetch(SiteInfoBean bean) throws IOException NV9H"fI  
{ >~\CiV4^  
siteInfoBean = bean; 7
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <_-8)abK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); IHj9n>c)[  
if(tmpFile.exists ()) r~T3Ieb
 
{ CI@qT}Y_  
bFirst = false; ?.,2EC=+  
read_nPos(); W.  p'T}2  
} L_}F.nbS5  
else jUy$aGX  
{ ]f3R;d  
nStartPos = new long[bean.getNSplitter()]; B0:/7Ld$Ml  
nEndPos = new long[bean.getNSplitter()]; u$mp%d8  
} *x&y24  
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} M}`G}*  
b "5WsJ:'#  
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public void run() @]B 7(j<'R  
{ 
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//获得文件长度 nh%Q";  
//分割文件 t}-rN5GO  
//实例FileSplitterFetch D2Dk7//82Y  
//启动FileSplitterFetch线程 G:{\-R'  
//等待子线程返回 r#/Bz5Jb*  
try{ \FjY;rqfKe  
if(bFirst) ;.b^A  
{ firiYL"=44  
nFileLength = getFileSize(); Be2yS]U  
if(nFileLength == -1) s@5r}6?M  
{ IP l]$j>N  
System.err.println("File Length is not known!"); u YJL^I8M'  
} [7gwJiK  
else if(nFileLength == -2) !7aJfs2  
{ Bhw|!Y&%  
System.err.println("File is not access!"); '@eH)wh@m)  
} Y(P<9m:  
else T'e p&tNY  
{ C\; $RH  
for(int i=0;i<nStartPos.length;i++) 73kL>u  
{ v(z2,?/4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &Ch~$Wb^  
} 'Mm=<Bh  
for(int i=0;i<nEndPos.length-1;i++) o|7 h  
{ #"aL M6Cfs  
nEndPos = nStartPos[i+1]; LkIbvJCV  
} [5QbE$  
nEndPos[nEndPos.length-1] = nFileLength; -O?&+xIK&  
} J1{ucFa  
} dSIZsapH  
^
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]eIV'lP,j/  
//启动子线程 ~3s\Q%   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; y`.m'n7>P  
for(int i=0;i<nStartPos.length;i++) ^ ]CQd   
{ U Zc%XZ`"V  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {]dH+J7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .3,6Oo  
nStartPos,nEndPos,i); z+6%Ya&
ls  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DU1
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fileSplitterFetch.start(); Gu@Znh-D  
} 9aZ^m$tAt  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }uk]1M2=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6i_dL|c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;B@-RfP  
nEndPos = " + nFileLength); ,]|*~dd>G  
// fileSplitterFetch[nPos.length-1].start(); xl;0&/7e  
c %.vI  
@mId{w z  
//等待子线程结束 MyJG2C#R  
//int count = 0; B5fF\N^  
//是否结束while循环 {>R'IjFc  
boolean breakWhile = false; _=RK  
1# X
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while(!bStop) Gmp`3  
{ S K7b]J>  
write_nPos(); w00
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Utility.sleep(500); *q |3QHZ  
breakWhile = true; C#4/~+  
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for(int i=0;i<nStartPos.length;i++) SHT^Etri  
{ [p[C45d=<  
if(!fileSplitterFetch.bDownOver) vQIN#;m4  
{ LX_{39?<{  
breakWhile = false; KHJk}]K  
break; 3Y+ bIz!  
} >*cg K}!@  
} =Frbhh57  
if(breakWhile) 5D%gD
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break; A%c)=(,  
m5rJY/  
J{bNx8.&  
//count++; #Bgq]6G2  
//if(count>4) KK4"H]!.  
// siteStop(); .WT^L2l%  
} f:|O);nM  
|8YP8o  
{r2fIj~V  
System.err.println("文件下载结束！"); s/J/kKj*s  
} J,=: ]t  
catch(Exception e){e.printStackTrace ();} #cD20t
 
} gaXKP1m^  
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iu(+ N~  
//获得文件长度 #J<IHN
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public long getFileSize() {-?8r>  
{ 0x/3Xz  
int nFileLength = -1; zr5(nAl  
try{ DTR/.Nr'K  
URL url = new URL(siteInfoBean.getSSiteURL()); bxA1fA;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @Xb>GPVe#L  
httpConnection.setRequestProperty("User-Agent","NetFox"); q=40l  
1-bQ ( -  
n%YG)5;  
int responseCode=httpConnection.getResponseCode(); @*rED6zH  
if(responseCode>=400) b[_${in:  
{ Nu%:7  
processErrorCode(responseCode); hfuGCD6F`  
return -2; //-2 represent access is error 'N?t=A  
} @ dF]X  
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}475c{  
String sHeader; @lnM%  
3!V$fl0  
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for(int i=1;;i++) Y!tjaL 9D  
{ 8K/o/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); q4rDAQyPO  
//Utility.log(in.readLine()); >7^
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sHeader=httpConnection.getHeaderFieldKey(i); r!7e:p JLO  
if(sHeader!=null) )QvuoaJQ  
{ G]- wN7G  
if(sHeader.equals("Content-Length")) w>W`8P_b@  
{ T|&2!Sh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^sjL@.'m$N  
break; L!]~J?)  
} sUP!'Av  
} @~l?hf  
else >.-$?2  
break; X;?Z_3I:5  
} *(4TasQu  
} Y/1,%8n  
catch(IOException e){e.printStackTrace ();} GqrOj++>  
catch(Exception e){e.printStackTrace ();} A|esVUo<3^  
9IRvbE~2  
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Utility.log(nFileLength); #1C~i}J1  
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return nFileLength; EdPN
=
 
} F|DKp[<]8  
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//保存下载信息（文件指针位置） 'C9H6)Zq)  
private void write_nPos() (3
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{ iWN-X (  
try{ .u_k?.8|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); XFg.Z+ #  
output.writeInt(nStartPos.length); g}-Ch#  
for(int i=0;i<nStartPos.length;i++) P"g Y|}|  
{ weOzs]uc  
// output.writeLong(nPos); h!*++Y?&0  
output.writeLong(fileSplitterFetch.nStartPos); WSY&\8
 
output.writeLong(fileSplitterFetch.nEndPos); -|DSfI#j  
} Q l
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output.close(); r12{XW?~  
} f~.w
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catch(IOException e){e.printStackTrace ();} /~LXY<-(  
catch(Exception e){e.printStackTrace ();} u%7a&1c  
} hCLXL  
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|@-%x.y  
//读取保存的下载信息（文件指针位置） WLAJqmC]  
private void read_nPos() >Ufjmm${  
{ ikGH:{  
try{ $DfaW3bJ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); J\%<.S>  
int nCount = input.readInt(); .=>T yq  
nStartPos = new long[nCount]; P'Fy,fNg  
nEndPos = new long[nCount]; y%H;o?<WX  
for(int i=0;i<nStartPos.length;i++) |-zwl8E  
{ r]{fjw(~  
nStartPos = input.readLong(); p.2>
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nEndPos = input.readLong(); O^]I>A#d  
} X'&$wQ6,K  
input.close(); TgaDzF,j{A  
} 3"gifE  
catch(IOException e){e.printStackTrace ();} )r2$/QF9  
catch(Exception e){e.printStackTrace ();} {}3kla{  
} ;!@\|E  
t#y  
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private void processErrorCode(int nErrorCode) 6Upg\(  
{ wE75HE`gW  
System.err.println("Error Code : " + nErrorCode); v`hv5wQ  
} \ooqa<_  
G
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WRAW%?$  
//停止文件下载 (%>Sln5hq  
public void siteStop() 9xg_M=72  
{ 2`* %NJ  
bStop = true; TKc&yAK  
for(int i=0;i<nStartPos.length;i++) j8os6I  
fileSplitterFetch.splitterStop(); Ar sMqb  
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} s\&_Kbw]c  
} Q
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//负责部分文件的抓取 &,Q{l$`X  
**FileSplitterFetch.java 71tMX[x  
*/ ]tZ5XS  
package NetFox; #{0DpSzE5  
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import java.io.*; |Z;wk&  
import java.net.*; L\og`L)5\  
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public class FileSplitterFetch extends Thread { Z-<v5aF  
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String sURL; //File URL T , =ga  
long nStartPos; //File Snippet Start Position P&aH6*p1  
long nEndPos; //File Snippet End Position DuvP3(K  
int nThreadID; //Thread's ID BH0rT})  
boolean bDownOver = false; //Downing is over U30)r+
&  
boolean bStop = false; //Stop identical ^TWN_(-@  
FileAccessI fileAccessI = null; //File Access interface 5?kA)!|UB  
Wsz='@XvB  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 16N8h]l  
{ `Ik}Xw  
this.sURL = sURL; 73~Mq7~8  
this.nStartPos = nStart; |->y'V  
this.nEndPos = nEnd; UKK}$B  
nThreadID = id; &SN$D5U'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (P#2Am$  
} i`]M2Q   
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public void run() ;(0:6P8I  
{ k7{fkl9|#  
while(nStartPos < nEndPos && !bStop) ga^<_;5<  
{ \N#)e1.0P  
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try{ <vt^=QA'  
URL url = new URL(sURL); <Awx:lw.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0K3FH&.%  
httpConnection.setRequestProperty("User-Agent","NetFox"); ($(1KE  
String sProperty = "bytes="+nStartPos+"-"; QrA8KSLC  
httpConnection.setRequestProperty("RANGE",sProperty); e3>Re![_.  
Utility.log(sProperty); _z4rx  
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InputStream input = httpConnection.getInputStream(); el|t6ZT*  
//logResponseHead(httpConnection); ~POeFZ  
^}1RDdQ"U  
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byte[] b = new byte[1024]; RO.(k!J .  
int nRead; sf*SxdoZU  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [!R%yD;  
{ bOz\-=au  
nStartPos += fileAccessI.write(b,0,nRead); LVEVCpp@  
//if(nThreadID == 1) ,Vs:Lle  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }BogE$tc  
} H9)uni   
''v1P
v-  
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Utility.log("Thread " + nThreadID + " is over!"); [S4\fy0  
bDownOver = true; *VlYl"  
//nPos = fileAccessI.write (b,0,nRead); H4:TYh  
} 6$6NVq  
catch(Exception e){e.printStackTrace ();} omjLQp[%  
} rFy9K4D  
} Na~_=3+a  
'6 'XBL?  
{hg$?4IyQ  
//打印回应的头信息 c&Zm>Qo[  
public void logResponseHead(HttpURLConnection con) g?$9~/h :;  
{ G>RYQ{O  
for(int i=1;;i++) C(0Iv[~y/  
{ 17i^|&J6}:  
String header=con.getHeaderFieldKey(i); =hs@W)-O  
if(header!=null) ai`:HhE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =!CuCV7$1O  
Utility.log(header+" : "+con.getHeaderField(header)); 2@&|hd=-  
else nIi_4=Z  
break; F>b6fUtR  
} Uqpvj90sw  
} 0&nF Vsz  
654%X(:q  
R$@.{d&:w  
public void splitterStop()
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{ {f&ga  
bStop = true; _
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} :> q?s  
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} Y@4vQm+  
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/* 8Cqs@<r4Od  
**FileAccess.java "|G,P-5G"  
*//文件访问(定位，写) m5p~>]}fYF  
package NetFox; "/'=gE  
import java.io.*; YQ)m?=+J  
i
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public class FileAccessI implements Serializable{ aO
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Ji!-G4.n"  
RandomAccessFile oSavedFile; 5VTbW   
long nPos; 0\#Q;Z2  
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public FileAccessI() throws IOException 'AAY!{>  
{ f5a](&  
this("",0); Xp~]kRm9  
} ;gMh]$|"  
"P{&UwMmh  
u .2sB6}  
public FileAccessI(String sName,long nPos) throws IOException W$JA4O>b  
{ 'MUrszOO.e  
oSavedFile = new RandomAccessFile(sName,"rw"); qc6IH9i`  
this.nPos = nPos; %yMzgk[u  
oSavedFile.seek(nPos); `-H:j:U{  
} YzZF^q^I  
.HBvs=i  
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public synchronized int write(byte[] b,int nStart,int nLen) Vd0GTpB?1  
{ qj6`nbZ{va  
int n = -1; t4IJ%#22  
try{ =vc5,  
oSavedFile.write(b,nStart,nLen); '/H(,TM
 
n = nLen; AVr!e   
} jVINc=o  
catch(IOException e) K*Jtyy}r  
{ K|G$s  
e.printStackTrace (); ja;5:=8A5  
} Vi#im`@  
>>$|,Q-.  
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return n; T,uIA]  
} gxOmbQt@;  
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} JC"K{V{  
)!d1<p3  
s.sy7%{  
/* 17cW8\  
**SiteInfoBean.java 'u[o`31.  
*/ \v
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package NetFox; 5gD)2Q6  
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public class SiteInfoBean { u =kSs  
6Qb)Uq3}]  
u mlZ(??.  
private String sSiteURL; //Site's URL ge?-^s4M  
private String sFilePath; //Saved File's Path ku
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private String sFileName; //Saved File's Name l,u{:JC  
private int nSplitter; //Count of Splited Downloading File V@:=}*E  
 ^qqHq  
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public SiteInfoBean() cf'}*$[S  
{//nSplitter的缺省值为5 

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//default value of nSplitter is 5 ?
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this("","","",5); 0lCd,a2:  
} 6B/"M-YME  
z8|9WZ:  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ZPsY0IzLo  
{ ?0NSjK5ma  
sSiteURL= sURL; 2w|u)ow)  
sFilePath = sPath; 9'q/&uH  
sFileName = sName; <88}+j  
this.nSplitter = nSpiltter; +)JqEwCrq  
|
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/JeqoM"x  
} W<91m*  
&PuJV +y  
s|r7DdI  
public String getSSiteURL() THgzT\_zq  
{ `U_>{p&x  
return sSiteURL; XOg(k(&T  
} KOEi_9i}  
DD 5EHJR  
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public void setSSiteURL(String value) 0t/y~TrBY  
{ ,,_K/='m  
sSiteURL = value; |D`b
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} Y"kS!!C>[  
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!VX_'GyK  
public String getSFilePath() G=!bM(]R~  
{ ;9p5YxD  
return sFilePath; 'eDgeWt/CQ  
} qj"syO  
[l%fL9  
/B@%pq  
public void setSFilePath(String value) +wW  
{ _@pf1d$  
sFilePath = value; kqig
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} &@utAuI  
11<@++,i  
L+rySP  
public String getSFileName() P9i9<pR  
{ vDeG20.?Z  
return sFileName; H.8CwsfP  
} 9=~H6(m>  
N"1x]1'  
x";.gjI |g  
public void setSFileName(String value) R^M (fC  
{ \1`DaQp7  
sFileName = value; W/r?0E  
} |z|)r"*\4  
^$+f3Z'  
|@L &yg,x  
public int getNSplitter() *_/eAi/WG  
{ G'?f!fz;  
return nSplitter; 7cmr *y  
} ]7S7CVDk4  
sJI-  
ym*#ZE`B!  
public void setNSplitter(int nCount) Y0X94k.u  
{ W[X!P)=w]  
nSplitter = nCount; Q`p}X&^a  
} 5@>4)dk\  
} *o e0=  
?sf2h:\N  
oj(A`[  
/* D*T$ v   
**Utility.java v(@+6#&  
*/ S5E,f?l  
package NetFox; OZB}aow  
.A"T086  
K~y9zF{  
public class Utility { l`FR.)2h  
aEFe!_QY  
w HHF=Q  
public Utility() w[YkTv  
{ v`+n`DT  
_2gT1B  
jU4)zN/`r  
} G9'YgW+$7  
+ersP@G  
//线程睡眠 ksOANLRN  
public static void sleep(int nSecond) w] 5U  
{ fv j5[Q  
try{ dy6F+V\DG  
Thread.sleep(nSecond); MY?O/,6  
} i5E:FS^!I  
catch(Exception e) iVpA@p   
{ |+;KhC  
e.printStackTrace (); 'tV"^KQHI  
} dJQ }{,+6  
} ]IHD:!Z-=  
+NLQYuN  
//日志 ^{fi^lL=  
public static void log(String sMsg) 4-d99|mv  
{ 7<QYT+6xV  
System.err.println(sMsg); *`g-gk  
} Z\*5:a]  
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??\*D9rCn  
public static void log(int sMsg) iUxDEt[t*  
{ w*6!?=jP  
System.err.println(sMsg); ,p*ntj{  
} 59Tg"3xB<  
} *3F /Ft5  
C:s^s  
`hK>bHj  
/* =N*%f%  
**TestMethod.java >G4HZE  
*/ 5}X
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package NetFox; anz9lGG#  
N.5KPAvg%  
V 4\^TO`q=  
public class TestMethod { 1%/ NL?8#  
hk"9D<&i>b  
2{sD*8&`  
public TestMethod() m|nL!Wc  
{ ///xx/weblogic60b2_win.exe J/]o WC`u  
try{ CSG+bqUG  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 
G%j/eTTf  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j:v~MrQ7|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); mI?* Z%>g  
fileFetch.start(); =2;mxJ#o  
} '.%iPMM  
catch(Exception e){e.printStackTrace ();} W>q*.9}Y"  
5I)~4.U|,m  
U+9-li  
} t-eKruj+  
_
#J_$CE#  
cYq']$]  
public static void main(String[] args) vR%j#v|s  
{ 1IOo?e=/bM  
new TestMethod(); _gPVmGG  
} 8u:v:>D.'  
} as\<nPT{Fj  
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