http断点续传简单实现（java)

/* St-:+=V_  
**SiteFileFetch.java LN ]ks)  
*/ ag]b]K  
package NetFox; xY(+[T!OF  
import java.io.*; n9]^v-]K  
import java.net.*; I:U/%cr,  
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public class SiteFileFetch extends Thread { e'[T5HI  
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SiteInfoBean siteInfoBean = null; //文件信息Bean h>sz@\{  
long[] nStartPos; //开始位置 lAJ)  
long[] nEndPos; //结束位置 0{F"b'h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 vD D !.i  
long nFileLength; //文件长度 YN?@ S  
boolean bFirst = true; //是否第一次取文件 JaKR#Y$+~  
boolean bStop = false; //停止标志 .{`+bT^b<2  
File tmpFile; //文件下载的临时信息 (9*s:)zD-  
DataOutputStream output; //输出到文件的输出流 o+;=C@,'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） wY
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public SiteFileFetch(SiteInfoBean bean) throws IOException @g9j+DcU  
{ ;38W41d{  
siteInfoBean = bean; TP{lt6wws(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )&1yt4 x6%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jV\M`=4IC  
if(tmpFile.exists ()) 1iS9f~  
{ 6#T?g7\pyR  
bFirst = false; LTp5T|O  
read_nPos(); WGN[`D"  
} Qc;`nck  
else
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{ cBmo#:>'  
nStartPos = new long[bean.getNSplitter()]; _55T  
nEndPos = new long[bean.getNSplitter()]; 8xj4N%PA  
} AJ2Xq*
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} -kZz,pNQ,  
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public void run() KD$P\(5#  
{ ^c< <I-o|  
//获得文件长度 }zRYT_
:  
//分割文件 6NbIT[LvT  
//实例FileSplitterFetch |4-c/@D.~  
//启动FileSplitterFetch线程 $8_t.~q  
//等待子线程返回 fdho`juFa  
try{ 7$x@;%xd  
if(bFirst) VPys  
{ 0vS%m/Zi-  
nFileLength = getFileSize(); $Pzvv`f*  
if(nFileLength == -1) *{Wh-bc  
{ 174H@  
System.err.println("File Length is not known!"); 9Vzk:zOT  
} }tft@,dIC  
else if(nFileLength == -2) jt"p Js'  
{ o1MbHBb  
System.err.println("File is not access!"); aP8Im1<A  
} hz Vpv,|G  
else dulW!&*No  
{ <$UMMA  
for(int i=0;i<nStartPos.length;i++) dT/Cn v=  
{ :J(a;/~ip  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); g.DgJX&i  
} G8QJM0VpS  
for(int i=0;i<nEndPos.length-1;i++) [+{ ot   
{ Bf1GHnXv  
nEndPos = nStartPos[i+1]; %E1~I\n:F  
} 5tP0dQYd
 
nEndPos[nEndPos.length-1] = nFileLength; K_]LK  
} 4mshB  
} |YZ`CN<  
p]!,BoZL  
s<:"rw`  
//启动子线程 DbPw)aCj  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8k_,Hni  
for(int i=0;i<nStartPos.length;i++) 8C,?Ai<ro  
{ wjS3ItB  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k]R O=/ ?M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), S31:}   
nStartPos,nEndPos,i); Nj#!L~^h,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mWmDH74  
fileSplitterFetch.start(); !G\1$"T$  
} gQ?>%t]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .4_~ku  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); S_?}H  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", EHzU`('?[  
nEndPos = " + nFileLength); g^B6NF  
// fileSplitterFetch[nPos.length-1].start(); akd~Z  
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5  
l*nSgUg  
//等待子线程结束 /DbwqBx  
//int count = 0; E_ mgYW*5  
//是否结束while循环 "ajZ&{Z  
boolean breakWhile = false; !Toq~,a8?  
E8%O+x}  
Jb ;el*,K  
while(!bStop) H7l[5ib  
{ /&kZ)XOi  
write_nPos(); NKGo E/  
Utility.sleep(500); {\]SvoJnJ  
breakWhile = true; i]Kq  
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for(int i=0;i<nStartPos.length;i++) <6(u%t0k5  
{ CuuHRvU8  
if(!fileSplitterFetch.bDownOver) >{m>&u;Cc  
{ 3l4k2  
breakWhile = false; UKX'A)$  
break; /8Vh G|Wb  
} 0CTI=<;  
} @Chj0wWZ>  
if(breakWhile) S;|%'Sn|j9  
break; T( ;BEyc?  
.'X$SF`  
=q6yb@  
//count++; (/qY*?  
//if(count>4) BJW;A>@Pj  
// siteStop(); +d#ZSNu/  
} Zqx5I~  
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System.err.println("文件下载结束！"); "h:xdaIE/p  
} [dt1%DD`M  
catch(Exception e){e.printStackTrace ();} 56TUh_  
} zH|!O!3"4  
mg#+%v  
Dj<Vn%d*  
//获得文件长度 p=Vm{i7  
public long getFileSize() /D~z}\k  
{ -Tz/ZOJ  
int nFileLength = -1; C9bf1ddCW&  
try{ V$:v~*Y9  
URL url = new URL(siteInfoBean.getSSiteURL()); 0eUsvzz15  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '<XG@L  
httpConnection.setRequestProperty("User-Agent","NetFox"); e%UFY-2  
I^lb;3uR  
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int responseCode=httpConnection.getResponseCode(); F;MFw2G  
if(responseCode>=400) eb:
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{ 8G{} r  
processErrorCode(responseCode); w/Q'T&>b/  
return -2; //-2 represent access is error L*L3;y|  
} r!#
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String sHeader; &|gn%<^  
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for(int i=1;;i++) &WsDYov?  
{ iyj&O"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); SJ+.i u/  
//Utility.log(in.readLine()); - d>)  
sHeader=httpConnection.getHeaderFieldKey(i); B23R9.FK  
if(sHeader!=null) r$.ek\D5  
{ ~W`upx)j  
if(sHeader.equals("Content-Length")) _>&zhw2  
{ IURi90Ir  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (obeEH5J  
break; Q=w\)qJ  
} Y+WOU._46I  
} sFB; /*C  
else j;<;?IW  
break; f3*u_LO  
} 2:2rwH }e  
} [Ma&=2h  
catch(IOException e){e.printStackTrace ();} g!aM-B
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catch(Exception e){e.printStackTrace ();} T
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| F:?  
Utility.log(nFileLength); Az"3f  
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return nFileLength; A^o  
} iVnrv`k,  
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,/JrQWgD  
//保存下载信息（文件指针位置） v)J
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private void write_nPos() %n!s{5:F  
{ k,b(MAiQ0  
try{ H}JH339  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &*L:4By)]  
output.writeInt(nStartPos.length); ILTd*f
 
for(int i=0;i<nStartPos.length;i++) mVU(u_lh  
{ i>0I '~V  
// output.writeLong(nPos); qFf'RgUtP  
output.writeLong(fileSplitterFetch.nStartPos); 0.|tKetHq  
output.writeLong(fileSplitterFetch.nEndPos); PX(Gx%s|  
} Y.jg }oV  
output.close(); ZYrd;9zB  
}
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catch(IOException e){e.printStackTrace ();} g"xLS}Al  
catch(Exception e){e.printStackTrace ();} c?b?x 6 2  
} K'n^, t  
I=Ws /+  
.|KxQn}  
//读取保存的下载信息（文件指针位置） I+8m1*  
private void read_nPos() -Qqb/y  
{ <k}>eGn  
try{ NfS0yQPx  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); BI,K?D&W-  
int nCount = input.readInt(); rWi
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nStartPos = new long[nCount]; <F>\Vl:  
nEndPos = new long[nCount]; kzgHp,;R{  
for(int i=0;i<nStartPos.length;i++) +JBhw4et;.  
{ K'N\"Y?>  
nStartPos = input.readLong(); 9v<BO$ ,a  
nEndPos = input.readLong(); qs 52)$  
} E^#|1Kpq  
input.close(); :#c?`>uV  
} :h*20iP  
catch(IOException e){e.printStackTrace ();} {Am\%v\  
catch(Exception e){e.printStackTrace ();} 6i%LM`8GEk  
} X#1So.}c  
_(J- MCY\  
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private void processErrorCode(int nErrorCode) $:/y5zi  
{ iN+p>3w^l  
System.err.println("Error Code : " + nErrorCode); mcS/-DaN?  
} U|-4*l9Ed  
{eqUEdC  
#B)/d?aa'  
//停止文件下载 m{(D*Vuqd  
public void siteStop() ldanM>5  
{ >sPu*8D40a  
bStop = true; tN";o\!}  
for(int i=0;i<nStartPos.length;i++) 2,q^O3F  
fileSplitterFetch.splitterStop(); )0fQ(3oOg  
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.=  
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} &FkKnz4IZ  
} ;&;coH8`  
//负责部分文件的抓取 J>]' {!+  
**FileSplitterFetch.java +7N6]pK|"  
*/ ZCbxL.fFz  
package NetFox; m$pXe<  
zrRt0}?xl  
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import java.io.*; ZRD*^9)  
import java.net.*; CHN!o9f  
9SC#N5V  
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public class FileSplitterFetch extends Thread { 3=T<c?[  
N$p}rh#7{  
i*W8_C:S  
String sURL; //File URL w v9s{I{P  
long nStartPos; //File Snippet Start Position e%(zjCA  
long nEndPos; //File Snippet End Position ~9h6"0K!  
int nThreadID; //Thread's ID sjWhtd[fgG  
boolean bDownOver = false; //Downing is over 2"yzrwZ:  
boolean bStop = false; //Stop identical D#W{:_f  
FileAccessI fileAccessI = null; //File Access interface n_.2B$JD  
8[(c'rl|)|  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException pb_mW;JVu  
{ :}UWy?F  
this.sURL = sURL; &=X1kQG  
this.nStartPos = nStart; '[`.&-;  
this.nEndPos = nEnd; Vy16Co  
nThreadID = id; 2Z7smDJ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ogip#$A}3  
} Q%o  
"EWU:9\0  
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public void run() 0pBlmPafY  
{ 4-ZiKM  
while(nStartPos < nEndPos && !bStop) H8Pil H  
{ rAn''X6H  
r_FW)Fu^  
]rZ"5y  
try{ RTHdL  
URL url = new URL(sURL); s:jr/ j!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u;h9Ra1  
httpConnection.setRequestProperty("User-Agent","NetFox"); K&D -1u  
String sProperty = "bytes="+nStartPos+"-"; 1S
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httpConnection.setRequestProperty("RANGE",sProperty); N#Qby4w >  
Utility.log(sProperty); F!c%&Z  
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InputStream input = httpConnection.getInputStream(); czdNqk.kh  
//logResponseHead(httpConnection); ULjW589zb  
PKwHq<vAsB  
 5t:4%  
byte[] b = new byte[1024]; pc^(@eD  
int nRead; Rj^bZ%t  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,yAvLY5P  
{ Ga N4In[d  
nStartPos += fileAccessI.write(b,0,nRead); rQj.W6w=  
//if(nThreadID == 1) lv&<kYWY  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]1abz:  
} 31Zl"-<#-  
+%UXI$v  
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Utility.log("Thread " + nThreadID + " is over!"); ? Yy[8_(tN  
bDownOver = true; 7EQ |p  
//nPos = fileAccessI.write (b,0,nRead); ;=F^G?p^  
} Pt";f  
catch(Exception e){e.printStackTrace ();} n
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} V8[woJ5x  
} lJR",_  
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py P5^Qv  
//打印回应的头信息 !_l W#feR  
public void logResponseHead(HttpURLConnection con) O'$0K0k3  
{ KB*[b  
for(int i=1;;i++) Kdik7jL/J  
{ G?'L1g[lc  
String header=con.getHeaderFieldKey(i); _9\ayR>d  
if(header!=null) Ks8S^77  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #x':qBv#  
Utility.log(header+" : "+con.getHeaderField(header)); S-.!BQ@RMZ  
else FyZw='D  
break; s-o0N{b?#'  
} y?CEV-3+  
} 19bP0y  
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public void splitterStop() VAsaJ`vcb  
{ 'WxcA)z0cQ  
bStop = true; l_>^LFO
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} 8yB  
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} HMrS::  
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/* "eZNci  
**FileAccess.java sW3-JA]  
*//文件访问(定位，写) +\\,FO_  
package NetFox; [=S@lURzm@  
import java.io.*; o-GlBXI;  
?P0$n 7,  
pR
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public class FileAccessI implements Serializable{ y5BNHweaRb  
8iqx*8}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o_bj@X  
RandomAccessFile oSavedFile; /DQoM@X  
long nPos; 9_KUUA  
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public FileAccessI() throws IOException 1i$9x$4~E  
{ na(@`(j[  
this("",0); bn~=d@'  
} 6_^u}me  
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public FileAccessI(String sName,long nPos) throws IOException &N[~+"  
{ 2}b1PMpZG  
oSavedFile = new RandomAccessFile(sName,"rw"); F1w~f <  
this.nPos = nPos; jiC;*]n  
oSavedFile.seek(nPos); daGGgSbh  
} C8-4 m68"  
kNd[M =%  
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public synchronized int write(byte[] b,int nStart,int nLen) B9>3xxp(by  
{ z )a8 ^]`  
int n = -1; kbM4v G  
try{ {%N*AxkvId  
oSavedFile.write(b,nStart,nLen); |L%F`K>Z:  
n = nLen; HZkC3$  
} Ac^}wXp  
catch(IOException e) _F;(#D  
{ FC.y%P,  
e.printStackTrace (); l`[*b_ Xt  
} !3kyPoq+  
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return n; VkRvmKYl  
} x6.an_W6  
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} 2%rAf8=  
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/* [3]!*Cd  
**SiteInfoBean.java %a{cJ6P  
*/ w`CGDF\Oo  
package NetFox; e7{3:y|]d3  
*jCXH<?R  
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public class SiteInfoBean { [`6|~E"F  
k8GcHqNHx  
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private String sSiteURL; //Site's URL X%h1r`h&  
private String sFilePath; //Saved File's Path [6FCbzS_W  
private String sFileName; //Saved File's Name u;F++$=  
private int nSplitter; //Count of Splited Downloading File qCc'w8A  
4IG'Tm  
s~Ni\SF  
public SiteInfoBean() )67Kd]  
{//nSplitter的缺省值为5 Hh(_sewo  
//default value of nSplitter is 5 /=FQ{tLr  
this("","","",5); zX"@QB3E  
} DHaSBk  
HZ>Xm6DnC5  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 0"ZB|^c=  
{ kg
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sSiteURL= sURL; G!ty@ Fx  
sFilePath = sPath; ",B92[}Ar  
sFileName = sName; xzyV|(  
this.nSplitter = nSpiltter; 5dXC  
EZ8Ih,j9  
W&A22jO.1  
} bO>Mvf  
3R !Mfz*  
V/.Y]dN5  
public String getSSiteURL() E@}t1!E<  
{ 5$`i)}:s  
return sSiteURL; #6 e  
} `|8)A)ZVT  
u#/Y<1gn  
LrX7WI  
public void setSSiteURL(String value) %i]q} M  
{ JcvWE $  
sSiteURL = value; %t([  
} 0vqXLFf   
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:5L9tNr{_  
public String getSFilePath() NJ/6_e  
{ RQ X  
return sFilePath; nBgksB*A  
} ?}D@{%O3T  
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public void setSFilePath(String value) a<kx95  
{ .8<bz4  
sFilePath = value; V44IA[  
} w6F4o;<PR  
?dl7!I@<E<  
iN %kF'&9  
public String getSFileName() ~gNa<t
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{ @{+c6.*}  
return sFileName; s_N?Y)lS+(  
} 6wYd)MDLL  
lM3UjR|@  
V2W)%c'  
public void setSFileName(String value) I0h/x5  
{ XkHO=  
sFileName = value; oP$NTy[  
} c`yLn%Of%  
}oIA*:5  
ZZL.&Ho  
public int getNSplitter() G'^Qi}o  
{ Z!0D97^  
return nSplitter; t|0Zpp;  
} _Y4%Fv>@  
>V2Tr$m j  
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public void setNSplitter(int nCount) f wWI2"}  
{ `f,SY  
nSplitter = nCount; Ob$|IH8.  
} ftw\oGrS  
} hF"yxucj$  
c|  
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/* ?B.>VnYZ/a  
**Utility.java =B@owx  
*/ k_ 9gMO  
package NetFox; -/*-e /+b  
]mYT!(}  
v)
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public class Utility { ZW{pO:-  
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R#.FfWTZ  
public Utility() >T[1=;o]  
{ PE4#dx^  
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~Wp>tnl  
} ;N6Euiz  

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//线程睡眠 Nb~.6bsL  
public static void sleep(int nSecond) oswS<t{Z  
{ E96FwA5  
try{ ;^za/h>r  
Thread.sleep(nSecond); PzbLbH8A  
} Lgw!S~0  
catch(Exception e) fA{[H:*}G  
{ qN%i$mJTo  
e.printStackTrace (); A0Pg|M  
} tu8n1W  
} &i179Qg!  
xs y5"  
//日志 FvQ>Y')R7Z  
public static void log(String sMsg) !

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{ .Az'THD}  
System.err.println(sMsg); x8YuX*/I  
} 'o;>6u<u  
V+myGsr`  
eT* )r~  
public static void log(int sMsg) @}k5rcQ*/  
{ MA1.I4dm  
System.err.println(sMsg); ]f#1G$  
} Loo48  
} c `C /U7j  
T<1*R>el  
{,61V;Bpm  
/* [9dW9[Z+!  
**TestMethod.java ,$BbJQ5  
*/ O}5mDx  
package NetFox; {}!`v%z  
</~!5x62Oy  
&qKJN#NM@  
public class TestMethod { V`Ve__5;  
Rg@W0Bc)  
Y|$3%t  
public TestMethod() Y~@@{zP  
{ ///xx/weblogic60b2_win.exe d;1%Ei3K  
try{ z2p@d1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <d!_.f}v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Ni"n_Yun  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Dg(882#_  
fileFetch.start(); =w&JDj  
} J;"66ue(d  
catch(Exception e){e.printStackTrace ();} !
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w$%d"Jm#X  
g*]Gc%  
} }Jfi"L  
Ch;C\H:X  
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public static void main(String[] args) (0Buo#I  
{ )1f8 H,q^  
new TestMethod(); t<~$?tuZ  
} >HMuh)  
} ,FWC|uM"  
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