http断点续传简单实现（java)

/* qL;OE.?oA  
**SiteFileFetch.java 4=BIYC"Lu  
*/ 3PmM+}j3  
package NetFox; #@rvoi  
import java.io.*; Q L0  
import java.net.*; ZDQc_{e{  
|"j{!Ei  
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public class SiteFileFetch extends Thread { s7"NK"  
]Alv5?E60  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8%eWB$<X  
long[] nStartPos; //开始位置 UDBMf2F]  
long[] nEndPos; //结束位置 ! MTmG/^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 O)bc8DyI  
long nFileLength; //文件长度 T?4pV#  
boolean bFirst = true; //是否第一次取文件 XLu Y  
boolean bStop = false; //停止标志 ~Ox !7Lp  
File tmpFile; //文件下载的临时信息 }Kt`du=  
DataOutputStream output; //输出到文件的输出流 2=\} 0  
Nk#[~$Q-1  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (hB+DPi  
public SiteFileFetch(SiteInfoBean bean) throws IOException })?t:zX#*  
{ <D_UF1Pk  
siteInfoBean = bean; ?pBQaUl&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,QB]y|:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Fv| )[>z0  
if(tmpFile.exists ()) 2LO8SJ#  
{
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bFirst = false; \ 5&-U@  
read_nPos(); r
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} d[0
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else DlMT<ld  
{ | e?:Uq  
nStartPos = new long[bean.getNSplitter()]; bS1?I@  
nEndPos = new long[bean.getNSplitter()]; )#(6J  
} ~Av
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} TJ_<21a  
}0y2k7^]  
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public void run() bR\Oyd~e  
{ [}mx4i  
//获得文件长度 JZl"k  
//分割文件 6Z}8"VJr {  
//实例FileSplitterFetch ,8tk]W[C  
//启动FileSplitterFetch线程 m }J@w~#  
//等待子线程返回 w \U?64  
try{ fk6`DUBV  
if(bFirst) tgR4C#a   
{ SsY:gp_  
nFileLength = getFileSize(); eBZ94rA]  
if(nFileLength == -1) s"'ns  
{ >bLhCgF:"  
System.err.println("File Length is not known!"); F|wT']1Y  
} @mD$Z09~  
else if(nFileLength == -2) hI$IBf>  
{ -eQ>3x&3r  
System.err.println("File is not access!"); f>!H<4 ]  
} D\4pLm"!v  
else Pg''>6w>  
{ hy]8t1894  
for(int i=0;i<nStartPos.length;i++) -4;$NiB?  
{ vWs#4JoG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ` P,-NVB  
} O>KrTK-A
V  
for(int i=0;i<nEndPos.length-1;i++) x+Ws lN2a  
{ : Yb_  
nEndPos = nStartPos[i+1]; 2]UwIxzR  
} K!<3|d  
nEndPos[nEndPos.length-1] = nFileLength;
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} Jv8JCu"eky  
} )wM881_!  
)w_hbU_Pb&  
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//启动子线程 75"&"*R/*G  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {0o,2]o!:  
for(int i=0;i<nStartPos.length;i++) YXlaE=9bn  
{ <K:L.c!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {Qf/.[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9<|nJt  
nStartPos,nEndPos,i); H"; !A=0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l:.q1UV  
fileSplitterFetch.start(); Ai*+LSG  
} 1C5~GI`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JYK
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); k^{}p8;3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", SR$?pJh D%  
nEndPos = " + nFileLength); %_L~"E 2e  
// fileSplitterFetch[nPos.length-1].start(); $ dR@Q?_{  
INRP@Cp1  
U&'Xsz  
//等待子线程结束 8+n*S$  
//int count = 0; wqasI@vyu  
//是否结束while循环 &-c{  
boolean breakWhile = false; ev[!:*6P  
mb?r{WCi  
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while(!bStop) X 2Zp@q(  
{ p6&6^v\  
write_nPos(); ']:>Ww.S  
Utility.sleep(500); ?Z2_y-  
breakWhile = true; ;39~G T  
+UX~TT:  
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for(int i=0;i<nStartPos.length;i++) 9
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{ :m[HUh  
if(!fileSplitterFetch.bDownOver) 3n)\D<f]#  
{ tE$oV  
breakWhile = false; ;[q>  
break; V2B: DIpr  
} AT-  
} U:fGIEz{ZY  
if(breakWhile) vPSY1NC5  
break; WX&0;Kr  
G Tz>}
@W  
mcb|N_#n/  
//count++; 6[3>[ej:x  
//if(count>4) eAK=ylF;  
// siteStop(); Yc-gJI*1  
} 6#;u6@+}yy  
y6P-:f/&*  
,K
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System.err.println("文件下载结束！"); ~(-df>  
} HXP/2&|JY  
catch(Exception e){e.printStackTrace ();} u):Nq<X  
} Z&6*8#wn  
8FJPw"9  
G\B:i
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//获得文件长度 1#lH5|XQ  
public long getFileSize() ~93#L_V_O  
{ I~&*8)x
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int nFileLength = -1; ?hOvY)  
try{ `s\E"QeZ
N  
URL url = new URL(siteInfoBean.getSSiteURL()); ^5Ob(FvU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /_V4gwb}|-  
httpConnection.setRequestProperty("User-Agent","NetFox"); Is(ZVI  
'R nvQ""  
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int responseCode=httpConnection.getResponseCode(); X_(n  
if(responseCode>=400) j
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{ >/9Qgyc0  
processErrorCode(responseCode); ~mvD|$1z  
return -2; //-2 represent access is error Q[&CtM  
} i{}Q5iy  
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4<S=KFT_  
String sHeader; .GiQC{@9w  
4v#A#5+O E  
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for(int i=1;;i++) N 8pzs"
 
{ feT.d +Fd  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vPET'Bf(YV  
//Utility.log(in.readLine()); \^Z DH  
sHeader=httpConnection.getHeaderFieldKey(i); '=(@3ggA:  
if(sHeader!=null) "rcV?5?v~  
{ !U~S7h}  
if(sHeader.equals("Content-Length")) MmW]U24s  
{  Eikt,
 
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));  Wo,fHY  
break; nq*D91Q  
} gezZYP)d  
} i,mo0CSa  
else Df}3^J~JX  
break; "[2D&\$  
} s>a(#6Q  
} t}2M8ue(&  
catch(IOException e){e.printStackTrace ();} SV
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catch(Exception e){e.printStackTrace ();} 3 Bn9Ce=  
8RJa;JsH  
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Utility.log(nFileLength); |K'7BK_^J  
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f=Kt[|%'e  
return nFileLength; 10ZL-7D#m  
} mO@S
l(9  
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vve[.Lud'  
//保存下载信息（文件指针位置） F=V_ACU  
private void write_nPos() B0ZLGB  
{ vf h*`G$  
try{ Wq/0
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output = new DataOutputStream(new FileOutputStream(tmpFile)); ($s%B  
output.writeInt(nStartPos.length);  r95$( N  
for(int i=0;i<nStartPos.length;i++) M6
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{ rE4qPzL  
// output.writeLong(nPos); -3Auo0  
output.writeLong(fileSplitterFetch.nStartPos); y9-}LET3j  
output.writeLong(fileSplitterFetch.nEndPos); Wf9K+my  
} kg()C%#u  
output.close(); |&\cr\T\r  
} `l<pH<F  
catch(IOException e){e.printStackTrace ();} =>Dw,+"  
catch(Exception e){e.printStackTrace ();} h 7*
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} ~.TKzh'eB  
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~MZ.988:<  
//读取保存的下载信息（文件指针位置） rtk1 8U-
 
private void read_nPos() j(`V&S
 
{ ZN-5W|' O  
try{ RLUH[[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~n9-  
int nCount = input.readInt(); 1" #W1im  
nStartPos = new long[nCount]; zHt}`>y&  
nEndPos = new long[nCount]; 1/vcj~|)t  
for(int i=0;i<nStartPos.length;i++) zK ir  
{ ]tO9<  
nStartPos = input.readLong(); GFO(O  
nEndPos = input.readLong(); #)28ESj  
} :t6.J  
input.close(); /rmm@  
} =f-.aq(G/  
catch(IOException e){e.printStackTrace ();} Xd@x(T~'X  
catch(Exception e){e.printStackTrace ();} gTqtTd~L  
} N0']t Gh2  
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private void processErrorCode(int nErrorCode)  -TKQfd  
{ ~0ZLaiJ  
System.err.println("Error Code : " + nErrorCode); 6)D
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} te8lF{R  
]x`I@vSf7R  
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//停止文件下载 jBnvu@K"  
public void siteStop() P1}Fn:Xe%7  
{ Vv5#{+eT;  
bStop = true; bhc .UmH  
for(int i=0;i<nStartPos.length;i++) 1 Ll<^P  
fileSplitterFetch.splitterStop(); {;Ispx0m  
cb9q0sdf  
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} 09C[B+>h  
} 8A3!XA  
//负责部分文件的抓取 ]Qb85;0)  
**FileSplitterFetch.java Q]2v]PJ6"  
*/ bx8|_K*^  
package NetFox; Ex3V[v+D(  
@&E{ L  
*Zi:^<hv  
import java.io.*;  C#x9RW  
import java.net.*; c=A)_ZFg  
LG3:V'|  
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public class FileSplitterFetch extends Thread { {Tym#  
p?+*R@O  
97n@HL1  
String sURL; //File URL ]@UJ 8hDy  
long nStartPos; //File Snippet Start Position Lv`NS+fX  
long nEndPos; //File Snippet End Position ,c_NXC^X?  
int nThreadID; //Thread's ID Uq}-<q  
boolean bDownOver = false; //Downing is over ;~5w`F)  
boolean bStop = false; //Stop identical f MDM\&f  
FileAccessI fileAccessI = null; //File Access interface |UZhMF4/-L  
C!r9+z)<  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v5!G/TZ1  
{ KZ}F1Mr  
this.sURL = sURL; FD*w4U5  
this.nStartPos = nStart; , ,=7deR  
this.nEndPos = nEnd; ><Z`)}
f  
nThreadID = id; V=|X=:fuih  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0/Wo":R:  
} p4-bD_  
4,pSC  
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public void run() 235wl  
{ X#!oG)or  
while(nStartPos < nEndPos && !bStop) ~Q)137u]P  
{ 8!uqR!M<C  
'WW['  
crdp`}}  
try{ dJ0qg_ U&  
URL url = new URL(sURL); MVpk/S%W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y8.(filNB  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,awp)@VG7  
String sProperty = "bytes="+nStartPos+"-"; 7iJ=~po:o  
httpConnection.setRequestProperty("RANGE",sProperty); 7f9i5E1  
Utility.log(sProperty); (ON_(MN   
j.L`@  

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InputStream input = httpConnection.getInputStream(); )FfJ%oT}  
//logResponseHead(httpConnection); jS,zdJs=  
#r4S%  
rZBOWT  
byte[] b = new byte[1024]; e~,/Z\i  
int nRead; 6s"Erq5q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
Py)'%e  
{ uBe1{Z  
nStartPos += fileAccessI.write(b,0,nRead); )~X*&(7RR}  
//if(nThreadID == 1) O]Mz1 ev|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '<YVDB&-d,  
} _(<D*V[  
pWwB<F  
bl)iji`]  
Utility.log("Thread " + nThreadID + " is over!");  FGP~^Dr/  
bDownOver = true; '"=Mw;p  
//nPos = fileAccessI.write (b,0,nRead); m%hUvG| i  
} J0hY~B~X  
catch(Exception e){e.printStackTrace ();} Q*+_%n1 /  
} 8VwByk8  
} `Oc`I9  
*&vySy
t  
ul',!js?  
//打印回应的头信息 1JU1XQi  
public void logResponseHead(HttpURLConnection con) u,6 'yB'u  
{ /{~cUB,Um  
for(int i=1;;i++) S}rW=hO  
{ -Oro$=%  
String header=con.getHeaderFieldKey(i); LK
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if(header!=null) !%x=o&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Z~-A*{u?  
Utility.log(header+" : "+con.getHeaderField(header)); &@dWd  
else @YEdN}es  
break; J6H3X;vxQw  
} Ti@X<C  
} kXq*Jq  
VvO/  
-k19BDJ,W  
public void splitterStop() +P~E54  
{ +C{ %pF  
bStop = true;
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} z5CWgN  
q?=eD^]  
#<7ajmr  
} "/)}Cc,L  
 'S f  
ZR3x;$I~4  
/* #0HF7C3  
**FileAccess.java xpf\S10e  
*//文件访问(定位，写) 3eV(2  
package NetFox; 43mV~Oj  
import java.io.*; 6'M"-9?G  
`3$S^|v  
=%:mZ@x'
 
public class FileAccessI implements Serializable{ }@pe`AF^  
mySm:ToT  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1f 0"z1
 
RandomAccessFile oSavedFile; ms8PFu(f  
long nPos; r"a4;&mf  
}31z 35  
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public FileAccessI() throws IOException %NbhR(  
{ 0;-S){  
this("",0); {.We%{
4V  
} f.gkGwNk  
7/;Xt&  
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public FileAccessI(String sName,long nPos) throws IOException k!]Tg"]JAh  
{ "jVMk  
oSavedFile = new RandomAccessFile(sName,"rw"); T x_n$ &  
this.nPos = nPos; P]Z}% 8^O  
oSavedFile.seek(nPos); <d
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} Te"<.0~1  
)T6+}   
,/\%-u? 1x  
public synchronized int write(byte[] b,int nStart,int nLen) |5}{4k~9J  
{ a4 g~'^uC  
int n = -1; 0;Y_@UVj  
try{ f8E S GU  
oSavedFile.write(b,nStart,nLen); uOEFb  
n = nLen; ;APpgt4  
} FU0&EO  
catch(IOException e) lqOv_q  
{ %}G:R!4 d  
e.printStackTrace (); DTdL|x.{  
} _Y*: l7  
cI3uH1;#  
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return n; V#W(c_g
 
} TA=Ij,z~  
,\5]n&T;r  
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} ^/HE_keY  
7581G$@ym  
RIUJ20PfYQ  
/* :yvUHx  
**SiteInfoBean.java S<Q6b_D  
*/ >P
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package NetFox; Dyp'a  
-aGv#!aIl  
-t %.I=|  
public class SiteInfoBean { Dj>.)n  
0[0</"K%1m  
^HKxaW9W  
private String sSiteURL; //Site's URL `3r*Ae  
private String sFilePath; //Saved File's Path 8oY0?|_Bx  
private String sFileName; //Saved File's Name {S\cpCI`  
private int nSplitter; //Count of Splited Downloading File C+}uH:I'L  
J3Q.6e=7  
8|7fd|6~  
public SiteInfoBean() VLtb16|  
{//nSplitter的缺省值为5 c
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//default value of nSplitter is 5 Y(/VW&K&:  
this("","","",5); (~{7e/)r  
} E/_=0t  
NF0} eom  
FFtj5e  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @ky
5XV  
{ }mz4 3Sq<  
sSiteURL= sURL; xYRL4  
sFilePath = sPath; LL-MZ~ZB  
sFileName = sName; \J0gzi.  
this.nSplitter = nSpiltter; =Ze~6vS,  
,Mc}U9)F  
&nj@t>5Bs$  
} VX&K
GG.6  
+YhTb  
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public String getSSiteURL() &e[/F@\%  
{ $K\\8$Z  
return sSiteURL; p=9G)VO  
} 1h]Dc(Oc#=  
n?aogdK$V  
\I#2Mq?  
public void setSSiteURL(String value) LtH;#Q  
{ Yk<?HNf  
sSiteURL = value; &e_M
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} p%J,af  
V|xR`Q  
0_qqBL.4  
public String getSFilePath() *BBP"_$  
{ a+zE`uY  
return sFilePath; K*;
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} X"8Jk4y  
tTF/$`Q#*  
)1J&tV*U  
public void setSFilePath(String value) _V6;`{$WK  
{ F:IG3 @  
sFilePath = value; HnioB=fc  
} v"_hWJ)  
&hd+x5  
z7{b>oub('  
public String getSFileName() r6 ,5&`&  
{ 8Z/P<u  
return sFileName; 4<Bj;1*4  
} kHX- AsRc  
5@O
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L4}C%c\p*  
public void setSFileName(String value) 8*4X%a=Of  
{ vYmRW-1Zxq  
sFileName = value; FL0(q>$*8  
} InNuK
0@  
uGc}^a2  
04:^<n+{  
public int getNSplitter() )"A+T&  
{ C#>c(-p>RC  
return nSplitter; zWB>;Z}  
} N}VKH5U|  
3HFsR)  
&cayhL/%  
public void setNSplitter(int nCount) `<y2l94tL  
{ |53Zg"!  
nSplitter = nCount; TS$ 2K  
} Q>JJI:uC4  
} cl1h;w9s  
M*8Ef^-U`t  
/S\P=lcb  
/* 1/6G&RB  
**Utility.java %{&yXi:mS  
*/ Po(9BRd7  
package NetFox; gAgzM?A1(  
noOG$P#  
@\z2FJ79w  
public class Utility { bb+-R_3Kd  
!4]wb
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 yYp!s
 
public Utility() =4m?RPb~b  
{ JQi)6A?J  
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} jUI'F4.5x-  
wb.47S8  
//线程睡眠 aJOhji<b#L  
public static void sleep(int nSecond) MY4cMMjp~  
{ zg0)9br  
try{ P8).Qn  
Thread.sleep(nSecond); Kt;h'?  
} FJp~8 x=  
catch(Exception e) d*3k]Ie%5f  
{ (Pbdwzao  
e.printStackTrace (); w2YfFtgD,  
} +P6q wh\v  
} yWsNG;>  
@iS(P u  
//日志 ~*- eL.  
public static void log(String sMsg) E Rqr0>x  
{ |.)oV;9  
System.err.println(sMsg); vtv|H  
} 5yuj}/PZ  
+0;6
.PK  
yO]Vex5)  
public static void log(int sMsg) GFYAg  
{ }tua0{N:z  
System.err.println(sMsg); ,L6d~>=41  
} g"FG7E&  
} >ys>Q)  
w(eAmN:zR  
iLws;3UX;x  
/* S c_*L<$  
**TestMethod.java @vCPX=c  
*/ 4=%Uv^M  
package NetFox; #78p#E  
q+>{@tP9  
m5v9:5{  
public class TestMethod {
XWf8ZZj  
B<I%:SkF@  
m`}! dBi  
public TestMethod() -*_D!  
{ ///xx/weblogic60b2_win.exe k>FMy#N|@  
try{ ZXY5Xvt:v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }f+If{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l|/h4BJ'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); B-@6m  
fileFetch.start(); Tu?+pz`h  
} e_kP=|u)g  
catch(Exception e){e.printStackTrace ();} Nh^T,nv*l  
{W)Kz_  
`M6!V  
} E*:!G  
1j`-lD  
Q&opnvN  
public static void main(String[] args) lQ<2Vw#Yl  
{ +\fr3@Yc  
new TestMethod(); =!*e; L  
} j#f+0  
} C\ZL*,%}  
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