http断点续传简单实现（java)

/* r|ogF8YN  
**SiteFileFetch.java y_T%xWK5  
*/ h@Ix9!?+  
package NetFox; jgBJs^JgYG  
import java.io.*; (i-L:  
import java.net.*; {T3wOi
  
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public class SiteFileFetch extends Thread { 6ciA|J'MR  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #y1M1Og  
long[] nStartPos; //开始位置 Jjh=zxR>  
long[] nEndPos; //结束位置 VgMuX3=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >n%ckL|rG  
long nFileLength; //文件长度 Kp6%
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boolean bFirst = true; //是否第一次取文件 iGNZC{  
boolean bStop = false; //停止标志 1:4u]$@E  
File tmpFile; //文件下载的临时信息 h#uk-7  
DataOutputStream output; //输出到文件的输出流 Cm-dos  
h2 >a_0"  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） MF+F8h>/  
public SiteFileFetch(SiteInfoBean bean) throws IOException x/%/MFK)>8  
{ _;:B@Z  
siteInfoBean = bean; j{HIdP  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;kD Rm'(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); cK'}+  
if(tmpFile.exists ()) ;>Z0e`=  
{ I3YSW  
bFirst = false; 
3 op{h6  
read_nPos(); th+LScOX  
} ;B;wU.Y"  
else 
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{ ~_ko$(;A  
nStartPos = new long[bean.getNSplitter()];
&& WEBQ  
nEndPos = new long[bean.getNSplitter()]; S*H @`Do%d  
} \_/dfmlIZ  
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} K^%ONultv  
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public void run() ilQt`-O!  
{ //yz$d>JN  
//获得文件长度 [2z >8SL  
//分割文件 8aW<lu  
//实例FileSplitterFetch >&Vz/0  
//启动FileSplitterFetch线程 qG#ZYcVec  
//等待子线程返回 \sS0@gnDI  
try{ l@>@2CB  
if(bFirst) /&yc?Ui  
{ Q 2B  
nFileLength = getFileSize(); ex|h&Vma2V  
if(nFileLength == -1) !~Kg_*IT  
{ m|PJwd6  
System.err.println("File Length is not known!"); z!)@`?  
} E+Dcw  
else if(nFileLength == -2) 8#RL2)7Uy`  
{ x(A6RRh  
System.err.println("File is not access!"); `Cz_^>]|=  
}
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else 7~
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{ m5cRHo<9Y  
for(int i=0;i<nStartPos.length;i++) n"nfEA3{`  
{ @Z Dd(xB&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); i.e4<|{  
} I\|.WrMNi  
for(int i=0;i<nEndPos.length-1;i++) 6Z{(.'Be  
{ >&Y\g?Z6G  
nEndPos = nStartPos[i+1]; {6>$w/+~  
} 0_-P~^A  
nEndPos[nEndPos.length-1] = nFileLength; -K6y#O@@  
} -6# _t  
} A1B%<$|pz  
E|_}?>{R  
BxB B](  
//启动子线程 zEw~t&:e  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; l_zTpyOZ  
for(int i=0;i<nStartPos.length;i++) Cw~fP[5XMF  
{ >txeo17Ba\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5e&;f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %.;;itB  
nStartPos,nEndPos,i); C9eisUM  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]aYuBoj  
fileSplitterFetch.start(); 2h1P!4W85  
} YAd%d|Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }bnodb^.7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4TSkm`iR  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", EEiWIf&S,  
nEndPos = " + nFileLength); DDZnNSo<JQ  
// fileSplitterFetch[nPos.length-1].start(); 1tlqw  
kT:?1w'  
c9+yU~(  
//等待子线程结束 }|l7SFst  
//int count = 0; c,}VC-  
//是否结束while循环 xggF:El3{  
boolean breakWhile = false; \9]-(j6[H  
imyfki $B  
_Zxo<}w}y  
while(!bStop) c~!ETwpHQ  
{ .>F
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write_nPos(); 877Kv);  
Utility.sleep(500); ;&MnPFmq  
breakWhile = true; 0R}hAK+| 4  
F
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for(int i=0;i<nStartPos.length;i++) j? Vs"d|  
{ yh.WTgcW  
if(!fileSplitterFetch.bDownOver) 'a>D+A:  
{ Wlp`D  
breakWhile = false; C#L|7M??;  
break; q XB E3  
} _AH_<Z(  
} {8,_[?H  
if(breakWhile) Pav  
break; SZvC4lOn#  
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sY?sQ'E2]  
//count++; =
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//if(count>4) tMyMA}`  
// siteStop(); }$s QmRR  
} :bXTV?#0  
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System.err.println("文件下载结束！"); o8SP#ET"n  
} @
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catch(Exception e){e.printStackTrace ();} TW=N+ye^1(  
} {,= hIXo>  
%
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//获得文件长度 olK*uD'`  
public long getFileSize() >S%}HSPKq  
{ <}F(G-kV6  
int nFileLength = -1; )M8@|~~  
try{ ,Bj]j -\Y  
URL url = new URL(siteInfoBean.getSSiteURL()); vgi`.hk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();

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httpConnection.setRequestProperty("User-Agent","NetFox"); juxAyds  
cG4}daK]d  
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int responseCode=httpConnection.getResponseCode(); W >|'4y)  
if(responseCode>=400) ^MVOaV65  
{ Omph(
  
processErrorCode(responseCode); ^}lL@Bd|  
return -2; //-2 represent access is error $SfY<j,R  
} ] ~}~d(  
>]2^5C;  
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String sHeader; &"Fz)}  
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for(int i=1;;i++) JvS ~.g1  
{ kRH D{6mol  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bn
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//Utility.log(in.readLine()); TJuS)AZ C  
sHeader=httpConnection.getHeaderFieldKey(i); %cASk>
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if(sHeader!=null) Bo ??1y  
{ milQxSpj  
if(sHeader.equals("Content-Length")) 1/SB[[g  
{ -o57"r^x  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1U ='"  
break; ^UyN)eX  
} {'#7b# DB>  
} jJ?G7Q5l  
else }MtORqK  
break; |V^f}5gd  
} K
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} l>)+HoD  
catch(IOException e){e.printStackTrace ();} %m$t'?  
catch(Exception e){e.printStackTrace ();} 2 S2;LB  
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Utility.log(nFileLength); 4 &0MB>m  

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return nFileLength; nyOvB#f  
} !RN9wXS7  
y tTppmJF  
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//保存下载信息（文件指针位置） ~!_UDD  
private void write_nPos() -#g0  
{ .[Ny(X/]/}  
try{ >Fc=F#tA9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &+/$~@OK  
output.writeInt(nStartPos.length); Zm#,Ike?#  
for(int i=0;i<nStartPos.length;i++) ""jl  
{ |xpOU*k  
// output.writeLong(nPos); \*c=b
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output.writeLong(fileSplitterFetch.nStartPos); s*vtCdrE.  
output.writeLong(fileSplitterFetch.nEndPos); .C1g Dry]  
} ")w~pZE&+  
output.close(); AS lmW@/9v  
} $C8s  
catch(IOException e){e.printStackTrace ();} q2M%AvR  
catch(Exception e){e.printStackTrace ();} N]G`]  
} OO;I^`Yn  
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//读取保存的下载信息（文件指针位置） Ex{;&UWm  
private void read_nPos() d/E0opv  
{ &]c7<=`K"  
try{ s2K8|q=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7s;*vd>  
int nCount = input.readInt(); l Ng)k1  
nStartPos = new long[nCount]; iF1zLI<A  
nEndPos = new long[nCount]; H)K.2Q  
for(int i=0;i<nStartPos.length;i++) oB+@05m8  
{ l#]+I YD  
nStartPos = input.readLong(); pH0MVu(W  
nEndPos = input.readLong(); epP_~TU  
} E,[v%Xw  
input.close(); D~,iI7ac  
} TH+TcYqO  
catch(IOException e){e.printStackTrace ();} W;8}`k  
catch(Exception e){e.printStackTrace ();} s_6Iz^]I  
} z{qn|#}  
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private void processErrorCode(int nErrorCode) 'A/f>W  
{ ,km`-6.2?  
System.err.println("Error Code : " + nErrorCode); M\kct7Y  
} ?q"9ZYX<  
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//停止文件下载 ?#L5V'ZZ*  
public void siteStop() 6Q`7>l.|?  
{ 9A}n
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bStop = true; a1ai?},  
for(int i=0;i<nStartPos.length;i++) ['I5(M@  
fileSplitterFetch.splitterStop(); G)%r|meKGB  
{;hRFQ^b  
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} M'$?Jp#]}  
} wVUm!Y  
//负责部分文件的抓取 )lVplAhZD  
**FileSplitterFetch.java smX&B,&@  
*/ OPDR
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package NetFox; q_:B=w+bC  
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import java.io.*; Y>K3.*.  
import java.net.*; q)]S:$?BT  
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public class FileSplitterFetch extends Thread { CePI{`&,  
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}do=lm?/  
String sURL; //File URL o[nr)  
long nStartPos; //File Snippet Start Position qox@_  
long nEndPos; //File Snippet End Position )eBCO~HS  
int nThreadID; //Thread's ID Yk5Cyq  
boolean bDownOver = false; //Downing is over 1@Rl^ey  
boolean bStop = false; //Stop identical =z2g}X  
FileAccessI fileAccessI = null; //File Access interface =UFmN"  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 200Fd8Ju  
{ 0EUC8Ni  
this.sURL = sURL; '>UQsAvm  
this.nStartPos = nStart; 9K#U<Q0b'  
this.nEndPos = nEnd; )7iYx{n  
nThreadID = id; (M,*R v  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .p\<niu7  
} o&rNM5:  
)n$RHt+:>  
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public void run() m H&WoL<K  
{ h?&S*)1  
while(nStartPos < nEndPos && !bStop) [\)irCDv  
{ gOn^}%4.I  
}I#,o!)Vd  
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try{ NSQf@o  
URL url = new URL(sURL); Su[f"2oR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 
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httpConnection.setRequestProperty("User-Agent","NetFox"); 6s&%~6J,  
String sProperty = "bytes="+nStartPos+"-"; gz`P~7-w:  
httpConnection.setRequestProperty("RANGE",sProperty); !T26#>mV  
Utility.log(sProperty); G+jcR; s  
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InputStream input = httpConnection.getInputStream(); RhumNP<M  
//logResponseHead(httpConnection); <,(Ww  
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8,&QY%8pX  
byte[] b = new byte[1024]; #W=H)6  
int nRead; qvN 5[rb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) nV?e
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{ j*@EJ"Gm>  
nStartPos += fileAccessI.write(b,0,nRead); O.wk
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//if(nThreadID == 1) -'::$ {  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S
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} HiDL:14  
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Utility.log("Thread " + nThreadID + " is over!"); <Z9N}wY,8  
bDownOver = true; (Qz| N  
//nPos = fileAccessI.write (b,0,nRead); MNsgD3  
} 9y5nG  
catch(Exception e){e.printStackTrace ();} ;p2a .P  
} -nC!kpo  
} -$5nqaK?  
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(  
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//打印回应的头信息 aG/L'weR  
public void logResponseHead(HttpURLConnection con) aT%6d@g  
{ 4Nz]LK%@  
for(int i=1;;i++) \J3n[6;  
{ K@+(6\6I  
String header=con.getHeaderFieldKey(i); rJ_fg$.<  
if(header!=null) '5m`[S-IU  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'Lv>!s 7  
Utility.log(header+" : "+con.getHeaderField(header)); /,#&Htk  
else :TN^}RML  
break; p+d?k"WN?  
} k6W [//  
} ys$X!Ep  
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public void splitterStop() *[[TDduh&  
{ <)$b=z  
bStop = true; !Typ_Cs  
} vaUUesy
tt  
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} Qg4g(0E@  
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:6X?EbXhK  
/* L BP|  
**FileAccess.java (3M7RpsL@  
*//文件访问(定位，写) U `<?~Bz  
package NetFox; \%011I4  
import java.io.*; S)[$F}  
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!^<%RT9@|  
public class FileAccessI implements Serializable{ }X[wWH  
h$eVhN&Vv  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 oN6 '%   
RandomAccessFile oSavedFile; |qTS{qQh{L  
long nPos; 8q#Be1u<s2  
- Ado-'aaS  
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public FileAccessI() throws IOException 13e @  
{ a)GT\1q  
this("",0); .~Z@y#  
} ON/U0V:v  
&fYV FRVkq  
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public FileAccessI(String sName,long nPos) throws IOException KQ(7%W  
{ 1P+Te,I  
oSavedFile = new RandomAccessFile(sName,"rw"); i VIpe  
this.nPos = nPos; v&i,}p^M5  
oSavedFile.seek(nPos); T1Y_Jf*KJ  
} l&1R`gcW  
nofK(0TF  
juc;]CHt'  
public synchronized int write(byte[] b,int nStart,int nLen) geB]~/-p  
{ Ue22,Pp6  
int n = -1; 8f0Ytfhw  
try{ $"G=r(MW  
oSavedFile.write(b,nStart,nLen); EZvf\s>LT  
n = nLen; qkbxa?&X  
} )0W-S9e<  
catch(IOException e) urK[v  
{ RRH[$jk  
e.printStackTrace (); rF8nz:8  
} O A9G] 8k  
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return n; Lu@'Ee!>G  
} N}tiaL4  
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} pZv>{=2hOS  
zU1[+JJY"{  
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/* 2PSt*(  
**SiteInfoBean.java [C"[#7  
*/ j >wT-s  
package NetFox; `K^j:fE7n  
8P#jC$<  
DNN60NX 5Q  
public class SiteInfoBean { ?g21U97Q  
*3>$f.
QU  
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private String sSiteURL; //Site's URL _;1H2o2f  
private String sFilePath; //Saved File's Path wUbs9y<  
private String sFileName; //Saved File's Name O$Z<R:vVA  
private int nSplitter; //Count of Splited Downloading File L93KsI  
M(_1'2  
}.j09[<  
public SiteInfoBean() RC| t-(Z  
{//nSplitter的缺省值为5 ZdP2}w  
//default value of nSplitter is 5 -Ob89Z?2A  
this("","","",5); h7h[!>  
} yj48GQP]  
P}Ud7Vil;l  
>(aGk{e1  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) jg_##Oha  
{ Kq*D_Rh2  
sSiteURL= sURL; /?,c4K,ap  
sFilePath = sPath; &XnbZ&_  
sFileName = sName; oMj;9,WK'  
this.nSplitter = nSpiltter; JNYFu0  
5#SD$
^  
/v,H%8S  
} ~J Xqyw}  
p+F{iMC  
s}pn5zMp:8  
public String getSSiteURL() j\Z/R1RcW  
{ 9. 7XRxR^  
return sSiteURL; )j[rm   
} PafsO,i-  
|rDv!m  
0Q1sJDa.  
public void setSSiteURL(String value)
</OZ,3J=  
{ pg%'_+$~m  
sSiteURL = value; 0rtP :Nj$  
} ZKv^q%92  
)+nY-DB(  
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public String getSFilePath() G/*0*&fW  
{ P;#}@/E  
return sFilePath; oq<n5  
} &Jr~)o   
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+Xg]@IS-eg  
public void setSFilePath(String value) M@n9i@UsO  
{ AJ*FQo.U  
sFilePath = value; AIR\>.~"i*  
} Q'ok%9q!p  
(\QkXrK  
0m|$ vb  
public String getSFileName() W\tSXM-Hg  
{ QQ5G?E  
return sFileName; b@yGa%Gz@  
} T@ [
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_Co*"hl>2  
+s}"&IV%  
public void setSFileName(String value) Q599@5aS  
{ u5,\Kz  
sFileName = value; ?y\gjC6CNG  
} `~bnshUk  
2^}E!(<  
*[(}rpp M  
public int getNSplitter() y3 R+060\3  
{ L;7x2&  
return nSplitter;
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} @@,
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1HF=,K+  
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public void setNSplitter(int nCount) $LLy#h?V]  
{ >^8=_i !  
nSplitter = nCount; =c-,uW11[  
} MMMuT^X  
} <3wfY #;><  
26c,hPIeXY  
`@acQs;0  
/* c({V[eGY  
**Utility.java tntQO!pM  
*/ q&h&GZ  
package NetFox; oCBZ9PGkK  
}=':)?'-.  
,<[Q/:}[  
public class Utility { s/,wyxKd  
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e%(,)WlTaU  
public Utility() |z!Y,zaX  
{ p?mQ\O8F  
ohHKZZ  
3
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} 'nOc_b0  
ltKUpRE\?  
//线程睡眠 gg>O:np8  
public static void sleep(int nSecond) 6n{`t/  
{ ~mqiXr8  
try{ `g2DN#q[0  
Thread.sleep(nSecond); `wJR^O!e  
} H5f>Q0jq  
catch(Exception e) +Mb;;hb  
{ uY,(3x  
e.printStackTrace (); -I$qe Xy  
} 6gLk?^.  
} t,mD{ENm&  
(RP"VEVR  
//日志 B?qLXRv  
public static void log(String sMsg) Jl-Lz03YG  
{ Pa.D+  
System.err.println(sMsg); OC$Y8Ofr  
} pg\Ylk"T  
6dG:3n}  
##gq{hgjb$  
public static void log(int sMsg) a&6e~E$K2  
{ 9V]\,mD=  
System.err.println(sMsg); J1waiOh  
} Oy:;v7  
} J2"n:  
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H'f
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/* a9CY,+z5B  
**TestMethod.java Le&SN7I  
*/ r sf +dC  
package NetFox; ]V,wIyC  
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public class TestMethod { Voi`OCut  
fdIO'L_  
> .L\>  
public TestMethod() G+^Q _w  
{ ///xx/weblogic60b2_win.exe gpBpG  
try{ ^-, aB  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); UN7>c0B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "r6DZi(^K  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wI!>IV(5  
fileFetch.start(); ?U~9d"2=  
} ;(cqaB  
catch(Exception e){e.printStackTrace ();} #$&!)13  
k_p4 f%9  
|[ymNG  
} *_ 2db  
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nE!h&}(  
public static void main(String[] args) |K(j}^1k  
{ sb"etc`w%-  
new TestMethod(); y^vB_[6l  
} -
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} J.
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