http断点续传简单实现（java)

/* &.?'i1!  
**SiteFileFetch.java ?5 7Sk+  
*/ `W*U4?M  
package NetFox; 9q[oa5INd  
import java.io.*; Dm<A ^
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import java.net.*; kPLxEwl  
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public class SiteFileFetch extends Thread { ]?[fsdAQW  
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SiteInfoBean siteInfoBean = null; //文件信息Bean s-T\r"d=j  
long[] nStartPos; //开始位置 0:Ol7  
long[] nEndPos; //结束位置 )P|),S,;Z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "LTad`]<Ro  
long nFileLength; //文件长度 A~t j/yq9  
boolean bFirst = true; //是否第一次取文件 BR yl4  
boolean bStop = false; //停止标志 }U"&8%PZr  
File tmpFile; //文件下载的临时信息 W:L AP R  
DataOutputStream output; //输出到文件的输出流 WI-1)1t  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #4 pB

@_  
public SiteFileFetch(SiteInfoBean bean) throws IOException hQDXlFHT  
{ r\V ={p  
siteInfoBean = bean; U\*J9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); AkQ~k0i}b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !d0kV,F:  
if(tmpFile.exists ()) 7O-x<P;  
{ H~1jY4E  
bFirst = false; w&T9;_/  
read_nPos(); SNI)9k(T{  
} Hja3a{LH  
else 5]Y?m'  
{ }S<2A7)el  
nStartPos = new long[bean.getNSplitter()]; kL"2=7m;  
nEndPos = new long[bean.getNSplitter()]; YteO6A;  
} 4@# `t5H  
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} %M|hA#04vZ  
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:  
public void run() 0^K">  
{ rCdu0 gYT  
//获得文件长度 b2&0Hx  
//分割文件 vnZC,J `  
//实例FileSplitterFetch RdRp.pb8  
//启动FileSplitterFetch线程 [:SWi1cK2  
//等待子线程返回 <lE<f+  
try{ ]|PiF+  
if(bFirst) _^%,x  
{ (M.&^w;`,  
nFileLength = getFileSize(); N64dO[op  
if(nFileLength == -1) Cd}<a?m,  
{ VQ9/Gxdeo  
System.err.println("File Length is not known!"); ) ahA[  
} Fyatd  
else if(nFileLength == -2) sN01rtB(UT  
{ 6zuTQ^pz  
System.err.println("File is not access!"); ou{2@"  
} %^1V4  
else D7Q$R:6|  
{ [j/9neaye  
for(int i=0;i<nStartPos.length;i++) N~zdWnSZ@G  
{ KF!Yf\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Od,qbU4O  
} fSvM(3Y<Qh  
for(int i=0;i<nEndPos.length-1;i++) _5Ct]vy  
{ R)s:rJQ=p  
nEndPos = nStartPos[i+1]; )cMh0SGcM1  
} jLHkOk5{:  
nEndPos[nEndPos.length-1] = nFileLength; S
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} Ls+2Zbh  
} Iom'Y@x  
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naz
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//启动子线程 Gm^U;u}=f  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; q ,]L$  
for(int i=0;i<nStartPos.length;i++) Zw S F^  
{ U$D65B4
=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N]=q|D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8\A#CQ5b  
nStartPos,nEndPos,i); ^KT Y?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); scz&h#0V  
fileSplitterFetch.start(); XW)lDiJl  
} !Pfr,a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Vd+T$uC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); C{xaENp  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w;:*P  
nEndPos = " + nFileLength); }-2 2XYh  
// fileSplitterFetch[nPos.length-1].start(); i#Bf"W{F  
ShP^A"Do  
u.m[u)HQ  
//等待子线程结束 A&Usddcp  
//int count = 0; ~/iKh11  
//是否结束while循环 9`X\6s  
boolean breakWhile = false; hT&Y#fh  
>rmqBDKaQ  
ZdWm:(nkU  
while(!bStop) bUdLs.:  
{ Nkth>7*  
write_nPos(); W/bQd)Jvk  
Utility.sleep(500); Ee%%d  
breakWhile = true; Q6!zZ))~  
qvKG-|j  
z3m85F%dR  
for(int i=0;i<nStartPos.length;i++) u?<%q!  
{ yfjWbW  
if(!fileSplitterFetch.bDownOver) Z4w!p?Wqa  
{ 6@F9G4<Z  
breakWhile = false; sW'AjI  
break; 17"uf.G  
} +`3)oPV)  
} ' ;FnIZ  
if(breakWhile) Ma']?Rb`  
break; E`usknf>l  
Hc$O{]sq  
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//count++; =M[bnq*\  
//if(count>4) PQSP&  
// siteStop(); jB Z&Ad@e  
} Q}K"24`=  
b;W3j  
M@H;pJ+B  
System.err.println("文件下载结束！"); 4ber!rJM  
} *:LK8U  
catch(Exception e){e.printStackTrace ();} x$.^"l-vX  
} L;NvcUFn  
?*1uN=oI{*  
o!Ieb  
//获得文件长度 ;yLu R  
public long getFileSize() g._]8{K  
{ v,{ :Ez(H  
int nFileLength = -1; *-=(Q`3  
try{ bL+_j}{:N  
URL url = new URL(siteInfoBean.getSSiteURL()); f<fXsSv(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }1c|gQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); PI:4m%[  
e L^|v  
p6]1w]*R  
int responseCode=httpConnection.getResponseCode(); 4I k{  
if(responseCode>=400) t?-n*9,#S  
{ BB!THj69a6  
processErrorCode(responseCode); j<99FW"@e  
return -2; //-2 represent access is error P%:wAYz1^O  
} ~"&|W'he[  
vkx7paY_  

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String sHeader; r?lf($D*  
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for(int i=1;;i++) y^,1a[U.  
{ R'bTN|Cq  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +\c5]`  
//Utility.log(in.readLine()); ^T;*M_  
sHeader=httpConnection.getHeaderFieldKey(i); :bu/^mW[  
if(sHeader!=null) G%AbC"  
{ \378rQU  
if(sHeader.equals("Content-Length")) 0w\
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{ 7Oa#c<2]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Pg0x/X{t  
break; mzaWST]  
} XSe=s
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} 5T_n %vz  
else 7$vYo _  
break; \Fbv
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} mPtZO*Fc  
} EyD=q! ZVZ  
catch(IOException e){e.printStackTrace ();} q77;ZPfs8  
catch(Exception e){e.printStackTrace ();} /ivJsPH  
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Utility.log(nFileLength); 8>2.UrC  
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return nFileLength; 3s,g*  
} 7a=gH2]&  
*/)c?)"  
DnMwUykF>0  
//保存下载信息（文件指针位置） @;zl  
private void write_nPos() w;[NH/A^a  
{ @Q ]
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try{ yYIf5S`V]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); zUkgG61  
output.writeInt(nStartPos.length); dUeN*Nq&(,  
for(int i=0;i<nStartPos.length;i++) BOb">6C  
{ KQaxvU)L  
// output.writeLong(nPos); @w#-aGJO  
output.writeLong(fileSplitterFetch.nStartPos); q1$N>;&  
output.writeLong(fileSplitterFetch.nEndPos); p*R;hU  
} }{K) 4M  
output.close(); W7R<%?  
} ??
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catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} {3>$[bT  
} Ga-k  
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//读取保存的下载信息（文件指针位置） jH5 k  
private void read_nPos() l[mWf  
{ ~NrG` D}  
try{ EnKR%Ctw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~9a<0Mc?  
int nCount = input.readInt(); I+%[d^,  
nStartPos = new long[nCount]; x*/tyZg6  
nEndPos = new long[nCount]; &=@IzmA  
for(int i=0;i<nStartPos.length;i++) 5Md=-,'J!  
{ sQUM~HD\a  
nStartPos = input.readLong(); ="1Ind@w!  
nEndPos = input.readLong(); {nBhdM:i  
} >\-hO&%_  
input.close(); E<{R.r  
} .;y.]Z/;  
catch(IOException e){e.printStackTrace ();} Z, zWuE3  
catch(Exception e){e.printStackTrace ();} #vz7y(v  
} Go`vfm"S  
e8>})  
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private void processErrorCode(int nErrorCode) lLX4Gq1  
{ 9Z@hPX3.  
System.err.println("Error Code : " + nErrorCode); GvtG(u~  
} KB3Htw%W[+  
?hZAxR\  
pz!Zs."f)
 
//停止文件下载 R$h<<v)%  
public void siteStop() 7X`g,b!  
{ 0#7>o^2  
bStop = true; 0cv{  
for(int i=0;i<nStartPos.length;i++) g+8OekzB5  
fileSplitterFetch.splitterStop(); /QK6Rac-  
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}
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} bQzZy5,  
//负责部分文件的抓取 xeg/
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**FileSplitterFetch.java e@L=LW>  
*/
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package NetFox; x77*c._3v  
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t>
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import java.io.*; Q
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import java.net.*; JinU
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public class FileSplitterFetch extends Thread { fF!Yp iI"  
h/QXPdV  
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String sURL; //File URL +C^nO=[E  
long nStartPos; //File Snippet Start Position _>o:R$ %}  
long nEndPos; //File Snippet End Position l] K3Y\#bP  
int nThreadID; //Thread's ID {X!r8i  
boolean bDownOver = false; //Downing is over =}<IfNA  
boolean bStop = false; //Stop identical 3<e=g)F  
FileAccessI fileAccessI = null; //File Access interface Yj<a" Gr4[  
7m47rJyW4  
J@/kIrx  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [7:,?$tC  
{ CQc+#nRe  
this.sURL = sURL; o3XvRj  
this.nStartPos = nStart; rP'me2 B  
this.nEndPos = nEnd; 0.Q Ujw  
nThreadID = id; =1@u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2,y|EpG#  
} 'NbHa!  
G~]Uk*M q  
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public void run() :;v~%e{k  
{ ]"p
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while(nStartPos < nEndPos && !bStop) ~V:\ _{mE  
{ WSPI|#Xr%  
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try{ xf'V{9*  
URL url = new URL(sURL); bS{bkE>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "6("9"  
httpConnection.setRequestProperty("User-Agent","NetFox"); `{
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String sProperty = "bytes="+nStartPos+"-"; nd`1m[7MNu  
httpConnection.setRequestProperty("RANGE",sProperty); FBG4pb9=~  
Utility.log(sProperty); B5`EoZ  
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InputStream input = httpConnection.getInputStream();  >^O7  
//logResponseHead(httpConnection); eYc$dPE  
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byte[] b = new byte[1024]; qRu~$K  
int nRead; -D<< kra  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q@=Q0  
{ zWnX*2>b  
nStartPos += fileAccessI.write(b,0,nRead); xPdG*OcX!  
//if(nThreadID == 1) \wmN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wC"FDr+  
} M+oHtX$  
XjBW9a  
05|=`eJ  
Utility.log("Thread " + nThreadID + " is over!"); )|ccX  
bDownOver = true; \a<wKTkn  
//nPos = fileAccessI.write (b,0,nRead); hy9\57_#  
} 1l9G[o *  
catch(Exception e){e.printStackTrace ();} Oz.HH  
} U
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} _OYasJUMG  
2bz2KB5>  
//B&k`u  
//打印回应的头信息 ;2G*wR  
public void logResponseHead(HttpURLConnection con) g%o(+d  
{ OUE(I3_  
for(int i=1;;i++) }ZYd4h|g\z  
{ 3s*mbk[J  
String header=con.getHeaderFieldKey(i); `4r 3l S  
if(header!=null) _9ao?:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +tB=OwU%0  
Utility.log(header+" : "+con.getHeaderField(header)); ]IaMp78
8  
else ~"gA,e-)  
break; rV.}PtcF
Y  
} ` #0:gEo  
} ;J'LS  
1> ?M>vK  
n>z9K')  
public void splitterStop() I
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{ >[f?vrz  
bStop = true; hy1oq7F(Q  
} 'I|v[G$l
 
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} !6 #X>S14  
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/* #I.+aV+2oQ  
**FileAccess.java u$z`   
*//文件访问(定位，写) &md`$a/  
package NetFox; +SzU  
import java.io.*; RIR\']WN  
x%=si[P  
t mntp
 
public class FileAccessI implements Serializable{ wKh4|Ka  
hwuiu*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]Ee?6]bN  
RandomAccessFile oSavedFile; VO5#
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long nPos; ^^u5*n+5  
y G~?MEh{  
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public FileAccessI() throws IOException ,O5NLg-  
{ ~i= _J3'  
this("",0); I@\lN&HC  
} BkAm/R
 
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public FileAccessI(String sName,long nPos) throws IOException @)F)S7  
{ >-?f0K  
oSavedFile = new RandomAccessFile(sName,"rw"); =>S]q71  
this.nPos = nPos; 5PCqYN(:B  
oSavedFile.seek(nPos); `?H]h"{7Q  
} -]Bq|qTH[(  
>tS'Q`R
 
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public synchronized int write(byte[] b,int nStart,int nLen) AOZP*\k  
{ b)#hSjWO#  
int n = -1; -:^U_FL8un  
try{ n)/z0n!\  
oSavedFile.write(b,nStart,nLen); ZmqKQO  
n = nLen; wVXS%4|v  
} &<g|gsG`  
catch(IOException e) Ju
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{ &;6`)M{*}  
e.printStackTrace (); 1UgEI"#a6g  
} `cn#B BV  
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return n; of~4Q{f$6  
} &3>)qul  
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} Y|m+dT6  
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/*
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**SiteInfoBean.java h8j.(  
*/ RU{twL.B  
package NetFox; ? V1*cVD6i  
yu {d! {6  
t,Lrfv])  
public class SiteInfoBean { >{]%F*p4  
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private String sSiteURL; //Site's URL tIi&;tw]  
private String sFilePath; //Saved File's Path dbLZc$vPj  
private String sFileName; //Saved File's Name OO\+J  
private int nSplitter; //Count of Splited Downloading File YDsb3X<0'  
;V_e>TyG  
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public SiteInfoBean() H'5)UX@LP  
{//nSplitter的缺省值为5 u
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//default value of nSplitter is 5 "!P3R1;%  
this("","","",5); %`r$g[<G  
} 5pG}Yk_(x  
tFn)aa~L  
+480 l}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,pfG  
{ )m+W j  
sSiteURL= sURL; F;EwQjTF  
sFilePath = sPath; P:S.~Jq  
sFileName = sName; uc{Ihw  
this.nSplitter = nSpiltter; g/_5unI}u  
5~U/  
2W(s(-hD  
} I|!OY`ko  
hag$GX'2k
 
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public String getSSiteURL() Gu,wF(x7A  
{ o[4}h:> dq  
return sSiteURL; l4YbKnp]  
} c]<5zyl"j1  
0o4XUW   
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public void setSSiteURL(String value) &B;~  
{ M?49TOQA  
sSiteURL = value; *R,5h2;  
} `hm-.@f,9  
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public String getSFilePath() }K>d+6qk5  
{ \K{ z  
return sFilePath; {?0lBfB"  
} 3%|&I:tI  
i"FtcP^  
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public void setSFilePath(String value) {z|)Njhg  
{ ,ng Cv;s  
sFilePath = value; S?LQu  
} 2.y-48Nz  
dQX6(Jj  
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public String getSFileName() nF:4}qy\  
{ 4@gG<QJW  
return sFileName; U>SShpmZA  
} T Z@]:e:"b  
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(E3b\lST  
public void setSFileName(String value) `[yKFa I  
{ 1H`,WQ1mG  
sFileName = value; =I5>$}q_&,  
} (L:>\m&NO  
n&/ `  
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public int getNSplitter() `RW HN/U  
{ Z\rwO>3  
return nSplitter; 4"ZP 'I;  
} YP<ms  
_61gF[r4!Y  
gJ+'W1$/  
public void setNSplitter(int nCount) VQ@  
{ e%M;?0j  
nSplitter = nCount; Y|qTyE%  
} {S\{Ii6  
} ?z+eWL  
{YC@T(  
]/6z; ~3U  
/* Ix}sK"}[n  
**Utility.java e`s ~.ZF  
*/ >R_&Ouh:  
package NetFox; G_JA-@i%  
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u#~RkY7s  
public class Utility { (WJRi:NP?  
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public Utility() T!{w~'=F  
{ NxY#NaE:?4  
^76]0`gS  
re<{ >  
} 
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wlvgg  
//线程睡眠 Z{d^-  
public static void sleep(int nSecond) 3?yg\  
{ i]4I [!  
try{ n@i HFBb  
Thread.sleep(nSecond); q2j{tP#  
} v?$:@9pAk  
catch(Exception e) JbbzV>  
{ "sCRdx]_  
e.printStackTrace (); +\A,&;!SR  
} Qv-_ jZ  
} rlLMT6r.8  
C!!M%P  
//日志 ]6`%  
public static void log(String sMsg) ObS3 M  
{ !.gIHY  
System.err.println(sMsg); ITBE|b  
}  (ZizuHC  
F>l] 9!P|m  
?l )[7LR4  
public static void log(int sMsg) Avc%2+  
{ \\qZl)P_  
System.err.println(sMsg); 59A}}.@?m  
} )akoa,#%6c  
} LL!Dx%JZ  
8<.Oq4ku  
Il'fL'3  
/* t*u:hex  
**TestMethod.java +6\Zj)  
*/ # W']6'O  
package NetFox; teF9Q+*~  
\b x$i*  
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public class TestMethod { ~0$&3a<n1  
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public TestMethod() F4
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{ ///xx/weblogic60b2_win.exe n>YKa)|W`  
try{ ,
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); da(<K}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); PZ9I`P!C  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
tsjrRMR  
fileFetch.start(); cwg"c4V  
} z:*|a+cy  
catch(Exception e){e.printStackTrace ();} Z9|P'R(l  
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bG#>uE J-  
} 5j(k:a+!H  
~>|ziHx  
8Z~EwY*  
public static void main(String[] args) iBaA9  
{ $&td=OK  
new TestMethod(); e"<OELA  
} VPo".BvG6  
} ,zjv7$L  
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