http断点续传简单实现（java)

/* Y4(  
**SiteFileFetch.java JMM W  
*/ [fIg{Q  
package NetFox; c0fo7|  
import java.io.*; 3[f): u3"  
import java.net.*; <^uBoKB/f  
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public class SiteFileFetch extends Thread { o8vug$=Z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean
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long[] nStartPos; //开始位置  rXU\  
long[] nEndPos; //结束位置 Oc; G(l(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2 Vrw  
long nFileLength; //文件长度 PiYxk+N  
boolean bFirst = true; //是否第一次取文件 pHJ
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boolean bStop = false; //停止标志
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File tmpFile; //文件下载的临时信息 (!N|Kl  
DataOutputStream output; //输出到文件的输出流 O8.5}>gDn.  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?K\axf>F  
public SiteFileFetch(SiteInfoBean bean) throws IOException jalg5`PU0  
{ ?S$P
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siteInfoBean = bean; I 2|Bg,e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &JI8]JmU)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (J!+(H8  
if(tmpFile.exists ())
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{ _f:W?$\ho  
bFirst = false; 7Rt9od< )!  
read_nPos(); >oe]$r  
} J9[r
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else ^ovR7+V  
{ H'hpEwG  
nStartPos = new long[bean.getNSplitter()]; `$C n~dT  
nEndPos = new long[bean.getNSplitter()]; 8pgEix/M5o  
} ,WB{i^TD  
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} /~f'}]W  
#ucBo<[  
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public void run() N'`A?&2ru  
{ cpJ|w3xB  
//获得文件长度 7x4PaX(  
//分割文件 t1y4 7fX6  
//实例FileSplitterFetch )TH@#1  
//启动FileSplitterFetch线程 0=E]cQwh  
//等待子线程返回 /d<P-!fK  
try{ ~La>?:g <+  
if(bFirst) EJNU761  
{ >s?S+W[L  
nFileLength = getFileSize();  YVanW  
if(nFileLength == -1) 'ub@]ru|  
{ $'hEz/  
System.err.println("File Length is not known!"); :A'y+MnK<  
} ';=O 0)u  
else if(nFileLength == -2) =rCIumqD-}  
{ pD#rnp>WWt  
System.err.println("File is not access!");
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} K
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else 8eHyL  
{ uGEfIy 2  
for(int i=0;i<nStartPos.length;i++) }d}Ke_Q0  
{ exUu7&*:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); xjj6WED  
} ?oHpFlj  
for(int i=0;i<nEndPos.length-1;i++) u($!z^h  
{ k{SAvKx=  
nEndPos = nStartPos[i+1]; d,n 'n  
} [e}]}t8m  
nEndPos[nEndPos.length-1] = nFileLength; (c &mCJN  
} 8C9-_Ng`  
} "u^H#L>-q  
P! #[mio  
+s DV~\Vu  
//启动子线程 T <ET )
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [}0haTYc4  
for(int i=0;i<nStartPos.length;i++) Vt&2z)Zz  
{ 76h ,]xi  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =mp;.k95  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4 VW[E1
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nStartPos,nEndPos,i); #KexvP&*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xRLT=.ir  
fileSplitterFetch.start(); aH/ k
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} k5.Ln
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X))/ m[_[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <s<n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S2G
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nEndPos = " + nFileLength); p xa*'h"b^  
// fileSplitterFetch[nPos.length-1].start(); PKg@[<g43  
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Xg!{K3OS  
//等待子线程结束 z !rL s76  
//int count = 0; Cl8Cg~2  
//是否结束while循环 CSq4x5!_7>  
boolean breakWhile = false; UIN<2F_  
hAnPXiD  
!/i{
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while(!bStop) }.m<  
{ YvyNHW&  
write_nPos(); mQ26K~  
Utility.sleep(500); ++Ts  
breakWhile = true; V_}"+&W9  
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T{ XS")Vw  
for(int i=0;i<nStartPos.length;i++) 9u}Hmb  
{ 3E
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if(!fileSplitterFetch.bDownOver) Q%tXQP.r  
{ W^LY'ypT  
breakWhile = false; ( !fKNia@S  
break; ;m{1_1  
} BdblLUGK#  
} ;d"F%M y  
if(breakWhile) Y}|X|!0x  
break; vJc-6EO
 
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//count++; {~"/Y@&]R  
//if(count>4) l=)x
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// siteStop(); n QZwC  
} ,I(d6  
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System.err.println("文件下载结束！"); Rmt~,cW!\  
} ][h%UrV  
catch(Exception e){e.printStackTrace ();} ]]9R mh=  
} ?u=Fj_N_  
j8{i#;s!"  
qqr?!vem6  
//获得文件长度 f:|1_j  
public long getFileSize() J1RJ*mo7,  
{ GmEJhr.3`=  
int nFileLength = -1; cyv`B3}  
try{ Z=Y& B>:[  
URL url = new URL(siteInfoBean.getSSiteURL()); pVw}g@<M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )SRefW.v  
httpConnection.setRequestProperty("User-Agent","NetFox"); QP8Ei
~  
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int responseCode=httpConnection.getResponseCode(); ]kRfB:4ED  
if(responseCode>=400) _] sn0rX  
{ lC("y' ::  
processErrorCode(responseCode); #+HJA42  
return -2; //-2 represent access is error `nv~NLkl  
} OXSmt DvJ  
1;r|g)VM  
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String sHeader; =9["+;\e&  
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for(int i=1;;i++) D4-ifsP  
{ JG!m
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Cc' 37~6~P  
//Utility.log(in.readLine()); AFDq}*2Qb  
sHeader=httpConnection.getHeaderFieldKey(i); G"U9E5O  
if(sHeader!=null) o_Z5@F  
{ K&ZtRRDd  
if(sHeader.equals("Content-Length"))

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{ $i}y8nlQ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); RJ ||}5  
break; aS{n8P6vW  
} z/WE,R  
} [.'|_l  
else &(G\[RWp\  
break;
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} 3kIN~/<R+7  
} zH4D8@[7O  
catch(IOException e){e.printStackTrace ();} ?{|q5n  
catch(Exception e){e.printStackTrace ();} \y)rt )  
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Utility.log(nFileLength); :W:K:lk  
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return nFileLength; K{cD+=
]{  
} V>)OpvoT#  
t?ZI".>  
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//保存下载信息（文件指针位置） c~$)UND^  
private void write_nPos() Y1OkkcPb{  
{ 4(~L#}:r!  
try{ Y. 5_6'Eo?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7he,?T)vD  
output.writeInt(nStartPos.length); goRL1L,5  
for(int i=0;i<nStartPos.length;i++) f/NH:1)y  
{ ?(y*nD[a  
// output.writeLong(nPos);  |`f$tj  
output.writeLong(fileSplitterFetch.nStartPos); Av$^  
output.writeLong(fileSplitterFetch.nEndPos); 7 60Y$/Wz  
} ?m=N]!n  
output.close(); *,)Md[  
} :q7Wy&ow  
catch(IOException e){e.printStackTrace ();} ,j}6? Q  
catch(Exception e){e.printStackTrace ();} 5C*Pd Wpl  
} *vN-Vb^2i)  
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P[#e/qnXu|  
//读取保存的下载信息（文件指针位置） trA4R/ &  
private void read_nPos() V>%rv'G8  
{ Ic:(Gi- %  
try{ ,I$`-$_'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); el<s8:lA  
int nCount = input.readInt(); WZejp}x  
nStartPos = new long[nCount]; gJXq^~-hd  
nEndPos = new long[nCount]; 9ni1f{k  
for(int i=0;i<nStartPos.length;i++)  $s c  
{ dA`IEQJL  
nStartPos = input.readLong(); E7Ul;d  
nEndPos = input.readLong(); 3cyHfpx-W  
} @=Uh',F  
input.close(); i2A8
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} A*R^n}sh  
catch(IOException e){e.printStackTrace ();} |y# Jx  
catch(Exception e){e.printStackTrace ();} S8w _ii3zd  
} v ~?qz5:K~  
>,Ci?[pf  
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private void processErrorCode(int nErrorCode) '!cCMTj  
{ TnOggpQ6X  
System.err.println("Error Code : " + nErrorCode); ksqQM
 
} 6V:U(g  
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2K6qY)/_  
//停止文件下载 c|B
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public void siteStop() )?naN  
{ o>i4CCU+  
bStop = true; A5RN5`}  
for(int i=0;i<nStartPos.length;i++) 4*#18<u5  
fileSplitterFetch.splitterStop(); qI9z;_,gNz  
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} '$IKtM`L  
} _LUhZlw  
//负责部分文件的抓取 \0I_<  
**FileSplitterFetch.java ,RI Gc US  
*/ Y>T-af49  
package NetFox; 8f4b&ah  
4Zddw0|2  
m@F`!qY~Y\  
import java.io.*; ~&_z2|UXp  
import java.net.*; T_ <@..C  
JCzeXNY  
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public class FileSplitterFetch extends Thread { D~iz+{Q4  
Uh4%}-;  
!bx;Ta.  
String sURL; //File URL )Y0!~# `  
long nStartPos; //File Snippet Start Position .x.]`b(  
long nEndPos; //File Snippet End Position ")5":V~fN  
int nThreadID; //Thread's ID rgv?gaQ>  
boolean bDownOver = false; //Downing is over l -mfFN  
boolean bStop = false; //Stop identical w"|L:8  
FileAccessI fileAccessI = null; //File Access interface 1..+F0U  
a=1@*ID  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nFe<w  
{ q=m'^ ,gPS  
this.sURL = sURL; oj<gD  
this.nStartPos = nStart; $am$EU?s  
this.nEndPos = nEnd; Xp% v.M  
nThreadID = id; wqs?828x  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 uc\Kg1{  
} e@07  
hJ? O],4J  
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public void run() #&k5d:  
{ JPUW6e07o  
while(nStartPos < nEndPos && !bStop) ,0Hr2*p  
{ mh#a#<  
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)}(^, Fo c  
try{ RnE4<Cy  
URL url = new URL(sURL); >J?fl8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6]N;r5n  
httpConnection.setRequestProperty("User-Agent","NetFox"); EU;9*W<  
String sProperty = "bytes="+nStartPos+"-"; >dD@j:Qc  
httpConnection.setRequestProperty("RANGE",sProperty); 1{.|+S Z!  
Utility.log(sProperty); 70nqD>M4  
L,`LN>  
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InputStream input = httpConnection.getInputStream(); 2(+
2+}  
//logResponseHead(httpConnection); q`a'gJx#y  
1#2 I  
@%uUiP0  
byte[] b = new byte[1024]; @ioJ]$o7  
int nRead; E_wCN&`[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6l1jMm|= X  
{ g2ixx+`?|:  
nStartPos += fileAccessI.write(b,0,nRead); lU\[aNs  
//if(nThreadID == 1) hH3RP{'=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h"Q8b}$^)  
} b3[!V{|  
!hy-L_wL]  
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Utility.log("Thread " + nThreadID + " is over!"); UnV.~u~  
bDownOver = true; ,PW'#U:  
//nPos = fileAccessI.write (b,0,nRead); H@>
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} i$#;Kpb`^  
catch(Exception e){e.printStackTrace ();} 5H9z4-i x?  
} gPO}d  
} KYI/  
8MtGlW%Eh  
"m8^zg hL  
//打印回应的头信息 @n /nH?L  
public void logResponseHead(HttpURLConnection con) ~jk|4`I?T  
{ $( kF#  
for(int i=1;;i++) "|q&ea rc  
{ #q$HQ&k  
String header=con.getHeaderFieldKey(i); ZJJY8k `  
if(header!=null) O _ gGf  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); v{N`.~,^  
Utility.log(header+" : "+con.getHeaderField(header)); !i}w~U<  
else 8/cX]J  
break; 5Ln,{vsv  
} M FMs[+2_o  
} BwpqNQN  
7S:\"A7  
Q"d^_z]K  
public void splitterStop() &PHTpkaam  
{ ;xj?z\=Pg  
bStop = true; |SSSH  
} /C:gKy4  
s!zx} 5  
o5PO=AN  
} rXP,\ ]r+  
AV]2euyn  
my1@41 H  
/* l|[N42+  
**FileAccess.java *:7rdzn  
*//文件访问(定位，写) cqkV9f8Ro  
package NetFox; qYQl,w  
import java.io.*; !9e=_mY  
~G&dqw/.-U  
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public class FileAccessI implements Serializable{ };zFJ6I8  
_;
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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 Gb6'n$g  
RandomAccessFile oSavedFile; d7y[0<xM  
long nPos; u&vf+6=9Dd  
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.  
public FileAccessI() throws IOException jB2[(  
{ v{4$D~I  
this("",0); K5h  
} t=iIY`Md%  

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(%6P0*  
public FileAccessI(String sName,long nPos) throws IOException g$-PR37(  
{ 9.-S(ZO  
oSavedFile = new RandomAccessFile(sName,"rw"); C{rcs'  
this.nPos = nPos; ~ .g@hS8>  
oSavedFile.seek(nPos); 2F.;;A
b  
} M7~2iU<#  
9cF[seE"0  
]%H`_8<gc  
public synchronized int write(byte[] b,int nStart,int nLen) q54]1TQ  
{ tDcT%D {:  
int n = -1; q<|AZ2Ai  
try{ tcI*a>  
oSavedFile.write(b,nStart,nLen); (?c"$|^J  
n = nLen; FVKTbvYn  
} iYoMO["X  
catch(IOException e) 7JH6A'&  
{ ~<bZ1TD   
e.printStackTrace (); #c!lS<z  
} Lk8ek}o'  
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1GcE)e!>  
return n; TD0 B%  
} Wac&b  
J*M>6Q.)  
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} wP@(?z  
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gwMNYMI  
/* _G@GpkSe>  
**SiteInfoBean.java ZY+qA  
*/ d#FQc18v}k  
package NetFox; ?:q*(EC<  
XRi8Gpg  
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public class SiteInfoBean { 73;GW4,  
CD~.z7,LC  
Xx:"4l.w.  
private String sSiteURL; //Site's URL L="}ErmK  
private String sFilePath; //Saved File's Path $U~]=.n  
private String sFileName; //Saved File's Name )Aqtew+A&  
private int nSplitter; //Count of Splited Downloading File h2R::/2.  
7{*>agQh  
gM:".Ee  
public SiteInfoBean() q2E_A  
{//nSplitter的缺省值为5 f ;n3&e0eC  
//default value of nSplitter is 5 Fx.=#bVX7  
this("","","",5); #_p\Ie*rd  
} sO@Tf\d  
zrb}_  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) O\r0bUPE  
{ {P_.~0pc*  
sSiteURL= sURL; 6i/(5 nQ  
sFilePath = sPath; 26h21Z16q  
sFileName = sName; b]KBgZ  
this.nSplitter = nSpiltter; R\[e!g*I  
sPIn|d  
FZnw0tMq  
} 3!]rmZ-W  
(GfZ*  
=Xr.'(U  
public String getSSiteURL() tWcHb #  
{ VOLj>w  
return sSiteURL; gPPkT"  
} WNtW|IV  
ww1[rCh\+  
]/L0,^RI  
public void setSSiteURL(String value) [7y]n;Fy  
{ 8":Q)9;%  
sSiteURL = value; SmO~,2=  
} K
}Qa~_  
WpvhTX  
3JR+O<3D  
public String getSFilePath() S f# R0SA  
{ <a3WKw  
return sFilePath; "w<#^d_6  
} R:qW;n%AF  
H Pz+Dm  
(E1~H0^  
public void setSFilePath(String value) |FRg\#kf%  
{ [nq@mc~<  
sFilePath = value; v]UwJz3<  
} (ToUgVW1N  
xAm6BB c  
a%0EiU  
public String getSFileName() $F.a><1rY  
{ [$UI8tV  
return sFileName; dM@1l1h/  
} J{G?-+`  
@H8EWTZ  
seJ^s@H5l  
public void setSFileName(String value) {'H(g[k  
{ \  Cj7k^  
sFileName = value; f|gg  
} aN3;`~{9  
?a]mD
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)4;`^]F  
public int getNSplitter() 0"z9Q\{}  
{ ,V}WM%Km  
return nSplitter; qH_Dc=~la  
} 1$ {SRU7l  
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a 1*p*dM#  
public void setNSplitter(int nCount) ,a? oaPH  
{ 9>#6*/Oa7  
nSplitter = nCount; \|[;Z"4l  
} G3
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}  %;!.n{X  
\_fv7Fdp{  
|y!A&d=xYn  
/* ,/unhfs1q  
**Utility.java DtnEi4h,  
*/ ],].zlN  
package NetFox; \'j|BJ~L f  
%&bY]w  
gBD]}vo-  
public class Utility { *X}`PF   
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public Utility() =2x^nW  
{ w4Z'K&d=  
7K:PdF>/  
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} 32 =z)]FZ  
 9gZ$
 
//线程睡眠 P!k{u^$L  
public static void sleep(int nSecond) |EN
h)M8}r  
{ Xn ;AZu^'R  
try{ NGWxN8P6  
Thread.sleep(nSecond); / XIhj  
} +ck}l2&#  
catch(Exception e) .N(p=9  
{ i}?>g-(  
e.printStackTrace (); Y<8vw d  
} /a o5FL  
} U/BR*Zn]*  
Tm?#M&'  
//日志 {(}By/_  
public static void log(String sMsg) Y <qm{e  
{ 9_s`{(0?  
System.err.println(sMsg); ?bu>r=oIO]  
} nQS|Lt_+  
L/^I*p,  
HpnWoDM  
public static void log(int sMsg) 8~gLqh8^V  
{ "zy7C*)>r  
System.err.println(sMsg); I<tm"?q0  
} 8\gjST*  
} /u+e0BHo  
n'w.; q  
PFK  '$  
/* WuW^GC{7  
**TestMethod.java ;*&-C9b  
*/ Yz<1 wt7;  
package NetFox; ete.!*=  
RpYERAgT  
Sa5G.^
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public class TestMethod { )\^-2[;  
`@s^(hc7i  
X\F|Tk3_  
public TestMethod() N}YkMJy  
{ ///xx/weblogic60b2_win.exe TuqH*{NNy9  
try{ FC"8#*x  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _wL BA^d^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WMg~Y"W  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8HdAFRw  
fileFetch.start(); {[>Kob1  
} ^sg,\zD 'X  
catch(Exception e){e.printStackTrace ();} sn>~O4"  
Ecx
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WMP,\=6k0  
} kO-(~];  
^zgo#J5O  
/H+a0`/  
public static void main(String[] args) 'A[dCc8O  
{ M& CqSd  
new TestMethod(); 4ss4kp_>  
} n{SJ_S#a.a  
} A.w:h;7  
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