http断点续传简单实现（java)

/* }|h# \$w  
**SiteFileFetch.java `V}q-Zdy
 
*/ X-b
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package NetFox; r8`ffH  
import java.io.*; |mZxfI  
import java.net.*; 0"jY.*_EW  
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public class SiteFileFetch extends Thread { .]8ZwAs=&  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %z=le7  
long[] nStartPos; //开始位置 /C
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long[] nEndPos; //结束位置 uy>q7C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5%Y3 Kwyy  
long nFileLength; //文件长度 {&&z-^  
boolean bFirst = true; //是否第一次取文件 ?g_3 [Fk  
boolean bStop = false; //停止标志 =Qy<GeY  
File tmpFile; //文件下载的临时信息 \j$&DCv
 
DataOutputStream output; //输出到文件的输出流 G<L;4nA)  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） S\CCrje  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?qb}?&1  
{ (d(CT;  
siteInfoBean = bean; /2&c$9=1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); LQ@"Xe]5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;YaQB#GK%  
if(tmpFile.exists ()) 6fkRrD  
{ 0CHH)Bku  
bFirst = false; 5?f ^Rz  
read_nPos(); Akq2 d;  
} Z%gh3  
else 6_(&6]}66  
{ d-oMQGOklb  
nStartPos = new long[bean.getNSplitter()]; !Jo_"#5  
nEndPos = new long[bean.getNSplitter()]; ]vAz  
} z<MsKD0Q  
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} +Q/R{#O  
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public void run() " s,1%Ltt  
{ GV1pn) 4  
//获得文件长度 esJ~;~[@(r  
//分割文件 v&6-a*<Z  
//实例FileSplitterFetch  {y)=eX9  
//启动FileSplitterFetch线程  CT&|QH{  
//等待子线程返回 b!+hH Hv:  
try{ `

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if(bFirst) =7?4eYHC  
{ l5~os>  
nFileLength = getFileSize(); d9k0F OR1  
if(nFileLength == -1) N:^n('U&j  
{ kXViWOXU^  
System.err.println("File Length is not known!"); EfqX y>W  
} [CY9^N  
else if(nFileLength == -2) &eJfGt5  
{ t$`r4Lb9/  
System.err.println("File is not access!"); &j;wCvE4+  
} ez7A4>
/  
else Mc)}\{J  
{ aEB_#1  
for(int i=0;i<nStartPos.length;i++) <;lkUU(WT2  
{ b]e"1Y)D-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &1Ok`_plO  
} L7l FtX+b  
for(int i=0;i<nEndPos.length-1;i++) ]>!K3kB  
{ Z*F3G#A  
nEndPos = nStartPos[i+1]; 11NQR[  
} 9p]QM)M  
nEndPos[nEndPos.length-1] = nFileLength; HVRZ[Y<^  
} wH*-(*N"  
} 7 W5@TWM  
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//启动子线程 1Yq!~8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; X;$+,&M"  
for(int i=0;i<nStartPos.length;i++) \$K20)  
{ 5%"V[lDx@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;[ZEDF5H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _O?`@g?i  
nStartPos,nEndPos,i); ibcRU y0%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *
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fileSplitterFetch.start(); fuW\bo3  
} 3<Lx&p~%T  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6bg ;q(*7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); y RqL9t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", RbB.q p  
nEndPos = " + nFileLength); _;"il%l=1  
// fileSplitterFetch[nPos.length-1].start(); Lj({[H7D!  
PI {bmZ  
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//等待子线程结束 H_7/%noS
5  
//int count = 0; 4Z3su^XR  
//是否结束while循环 1C+13LE$U  
boolean breakWhile = false; "Bkfoi  
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cVv=*81\  
while(!bStop) `bq
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{ }RF(CwZr(  
write_nPos(); g&L!1<, p  
Utility.sleep(500); 70?\ugxA  
breakWhile = true; Z-%\ <zT  
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for(int i=0;i<nStartPos.length;i++) M/f<A$xx_  
{ #
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if(!fileSplitterFetch.bDownOver) H*n-_{h"t  
{ [jQp
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breakWhile = false; &u."A3(  
break; CO/]wS  
} `v!urE/gg%  
} 9cbd~mM{  
if(breakWhile) h,:m~0gmj  
break; gjyYCjF  
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//count++; [>I<#_
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//if(count>4) +fB5w?Rg  
// siteStop(); ),%%$G\  
} K8|r&`X0  
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System.err.println("文件下载结束！"); 6_o*y8s.  
} $S6`}3  
catch(Exception e){e.printStackTrace ();} s[>,X#7 y  
} 7~h<$8Y(T  
C^Yb\N}S  
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//获得文件长度 u{cW:  
public long getFileSize() l'rja.\  
{ P= BZ+6DS  
int nFileLength = -1; ?>:g?.+  
try{ U+jOTq8M  
URL url = new URL(siteInfoBean.getSSiteURL()); e*kpdS~U&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &J]K3w1p  
httpConnection.setRequestProperty("User-Agent","NetFox"); Pbn*
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2  
int responseCode=httpConnection.getResponseCode(); z|J_b"u4  
if(responseCode>=400) HVCe;eI  
{ eb\K "ec"  
processErrorCode(responseCode); tKuwpT1Qc  
return -2; //-2 represent access is error "S]0  
} X,% 0/6*]  
4"(Bu/24  
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String sHeader; 9rX&uP)j^#  
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for(int i=1;;i++) D/gw .XYL  
{ .hb:s,0mP  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5V~oIL  
//Utility.log(in.readLine()); C 82omL  
sHeader=httpConnection.getHeaderFieldKey(i); xIW3={b3  
if(sHeader!=null) wU36sCo  
{ Vm(y7}Aq{  
if(sHeader.equals("Content-Length")) Ml{,  
{ p`dU2gV  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2a)xTA#  
break; FX&~\kmV'j  
} 6Pnjmw.HV  
} 1-uxC^u?|#  
else m9WDT  
break; &ywPuTt  
} ~Ffo-Nd-  
} s c,Hq\$&  
catch(IOException e){e.printStackTrace ();} 4Z=_,#h4.  
catch(Exception e){e.printStackTrace ();} (,\+tr8r8  
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U}[
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Utility.log(nFileLength); bH9kj/q\b  
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return nFileLength; &{hL&BLr  
} 49c:
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/Iy
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//保存下载信息（文件指针位置） SM#]H-3  
private void write_nPos() ^mDe08. %b  
{ VcYrK4  
try{ ek\ xx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); rU:
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output.writeInt(nStartPos.length); 8W(*~}ydYY  
for(int i=0;i<nStartPos.length;i++) Vb;*m5,?:  
{ 2;`1h[,-^  
// output.writeLong(nPos); #Y`~(K47  
output.writeLong(fileSplitterFetch.nStartPos); ? (Oy\  
output.writeLong(fileSplitterFetch.nEndPos); N)|yu1S
 
} 6<SAa#@ey  
output.close(); %lhEM}Sm  
} c|y(2K)o[=  
catch(IOException e){e.printStackTrace ();} /{l$sBUL  
catch(Exception e){e.printStackTrace ();} }OR@~V{Gj  
} G6P?2@  
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,eW%{[g(  
//读取保存的下载信息（文件指针位置） ^ogt+6c  
private void read_nPos() GW@;}m(  
{ sqwGsO$#  
try{ jXx<`I+]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Yui3+}Ms  
int nCount = input.readInt(); F#Ryu~,"  
nStartPos = new long[nCount]; 3{64 @s  
nEndPos = new long[nCount]; {X+3;&@  
for(int i=0;i<nStartPos.length;i++) O, wJR  
{ %P/Jq#FE.  
nStartPos = input.readLong(); S(lO(gY  
nEndPos = input.readLong(); )p0^zv{  
} l`{\"#4  
input.close(); =`F(B  
} ]=I@1B;_m  
catch(IOException e){e.printStackTrace ();} +F` S>U  
catch(Exception e){e.printStackTrace ();} qvsd5PeCO  
} W]1)zO  
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private void processErrorCode(int nErrorCode) qp}Cqi  
{ O2E/jj  
System.err.println("Error Code : " + nErrorCode); ~9]hV7y5C  
} w~A{(- dx  
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//停止文件下载 o Q2Fjj  
public void siteStop() `Bp.RXsd*  
{ *uf'zQ<9  
bStop = true; 8 &LQzwa  
for(int i=0;i<nStartPos.length;i++) =pO^7g  
fileSplitterFetch.splitterStop(); $E~`\o%Ev  
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7M!I8C0!aO  
} cWaSn7p!X  
} I\{ 1u  
//负责部分文件的抓取 Y@vTaE^w3  
**FileSplitterFetch.java 9'giU r  
*/ W=><)miQ@  
package NetFox; @7]yl&LZ  
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import java.io.*; kk@fL  
import java.net.*; xb~yM%*c  
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public class FileSplitterFetch extends Thread { Tod&&T'UW  
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String sURL; //File URL zuad~%D<I  
long nStartPos; //File Snippet Start Position T{.pM4Hd  
long nEndPos; //File Snippet End Position ?m}
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int nThreadID; //Thread's ID r&JgLC(   
boolean bDownOver = false; //Downing is over 4y?n [/M/  
boolean bStop = false; //Stop identical u(>^3PJ+  
FileAccessI fileAccessI = null; //File Access interface p!7FpxZY  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException '(f*2eE:  
{ .m,_N@,  
this.sURL = sURL; @ $ ;q;  
this.nStartPos = nStart; ]d0BN`*U.  
this.nEndPos = nEnd; U0y%u  
nThreadID = id; Eu d*_>|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %KhI>O<  
} Ys!82M$g  
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public void run() qZtzO2Mt  
{ !mJ"gg  
while(nStartPos < nEndPos && !bStop) {0wIR_dGX  
{ t
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try{ $oID(P  
URL url = new URL(sURL); |`2RShu  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KE5kOU;  
httpConnection.setRequestProperty("User-Agent","NetFox"); q]ku5A\y  
String sProperty = "bytes="+nStartPos+"-"; kWMl  
httpConnection.setRequestProperty("RANGE",sProperty); ooj,/IEQ  
Utility.log(sProperty); 3tIVXtUCUk  
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InputStream input = httpConnection.getInputStream(); mZS >O_E  
//logResponseHead(httpConnection); kX7C3qdmt  
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byte[] b = new byte[1024]; \O3m9,a   
int nRead; A5I)^B<(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) rxvx  
{ MDZ640-Y  
nStartPos += fileAccessI.write(b,0,nRead); KK/tu+"  
//if(nThreadID == 1) _ @NL;w:!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kzQ+j8.,U  
} X; \+<LE  
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Utility.log("Thread " + nThreadID + " is over!"); 45@ I*`  
bDownOver = true; n?!">G  
//nPos = fileAccessI.write (b,0,nRead); &WuN&As!Z  
} HSE!x_$  
catch(Exception e){e.printStackTrace ();} +ZaSM~   
} ~?Qe?hB  
} S}m)OmrmA  
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,GbR!j@6  
//打印回应的头信息 UJAv`yjG  
public void logResponseHead(HttpURLConnection con) 1y@i}<9F  
{ ]b:Lo  
for(int i=1;;i++) 8sWJcmVo  
{ 17%,7P9pg  
String header=con.getHeaderFieldKey(i); <s31W3<v  
if(header!=null) 0y'H~(  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); GbY7_N  
Utility.log(header+" : "+con.getHeaderField(header)); lHY+}v0  
else `_Zg3_K.dS  
break; jP$a_hW  
} wY{-BuXv  
} .=7vI$ujd  
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public void splitterStop() W fN2bsx>  
{ V5nwu#  
bStop = true; ky,(xT4  
} <SAzxo:I  
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} ~]IOK$1F%  
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/* ntX3Nt_n  
**FileAccess.java :\`o8`
 
*//文件访问(定位，写) }#RakV4  
package NetFox; ,GhS[VJjR  
import java.io.*; ,hm\   
X6w6%fzOH>  
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public class FileAccessI implements Serializable{ Wq D4YGN  
2G& a{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d=$Mim  
RandomAccessFile oSavedFile; Z!a=dnwHz  
long nPos; ~k-y &<UR  
7FP*oN?  
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public FileAccessI() throws IOException 6m/r+?'  
{ U/66L+1  
this("",0); [x=s(:qy  
} 13$%,q
)  
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public FileAccessI(String sName,long nPos) throws IOException i(rL|d+'  
{ >;aWz%-  
oSavedFile = new RandomAccessFile(sName,"rw"); z3{G9Np  
this.nPos = nPos; n:I,PS0H<  
oSavedFile.seek(nPos); Q",t3i4  
} ^KnU4sD  
kUL'1!j7  
7JD' )
 
public synchronized int write(byte[] b,int nStart,int nLen) -lr vKrt7  
{ [r\Du|R-*  
int n = -1; A_"w^E{P  
try{ &)# ihK_  
oSavedFile.write(b,nStart,nLen); b"<liGh"n-  
n = nLen; #X+JHl  
} :[.vM  
catch(IOException e) IEL%!RFG  
{ 6fE7W>la  
e.printStackTrace (); [t m_Mg  
} bi',j0B  
:;%2BSgFU  
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return n; y;m|  
} i<C*j4qQ  
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} 9d0@wq.  
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/* gs^Xf;gvI  
**SiteInfoBean.java *?@?f&E/  
*/ ]\-A;}\e  
package NetFox; ch*8B(:  
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p%up)]?0  
public class SiteInfoBean { T= 80,  
\i>?q  
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private String sSiteURL; //Site's URL o"s)eh  
private String sFilePath; //Saved File's Path W
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private String sFileName; //Saved File's Name k&M;,e3v6  
private int nSplitter; //Count of Splited Downloading File f=+
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JMCKcZ%N  
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public SiteInfoBean() gi3F` m  
{//nSplitter的缺省值为5 rET\n(AJ  
//default value of nSplitter is 5 @W.S6;GA\  
this("","","",5); <q58uuK  
} ^`i#$  
^x]r`b  
:I]Mps<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B9_X;c  
{ X;+sUj8  
sSiteURL= sURL; ~Py`P'+  
sFilePath = sPath; ;DQ ZT  
sFileName = sName; wA ,6bj  
this.nSplitter = nSpiltter; *xAqnk   
~f2z]JLr:  
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} 1 &jc/*Z"  
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public String getSSiteURL() /aCc17>2V{  
{ 8L=HW G!1  
return sSiteURL; I.(,hFx;  
} {S]}.7`l9(  
olB.*#gA  
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public void setSSiteURL(String value) LtO!umM  
{ +yG~T  
sSiteURL = value; tn\yI!a  
} -vo})lO  
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vQG5*pR*w  
public String getSFilePath() @Rze| T.  
{ ;J( 8 L  
return sFilePath; Rxt^v+ ,$  
} eI}aQ]$ED  
e-
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public void setSFilePath(String value) y-pJF{ R  
{ n: ^ d|@  
sFilePath = value; 4/~E4"8  
} gT{Q#C2Baw  
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8.1c?S  
public String getSFileName() 'T;P;:!\  
{ _IHV7*u{;  
return sFileName; HQ_Ok`  
} ^rR1ZVY  
v|,1[i{  
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public void setSFileName(String value) {GT*ZU*  
{ lWk>z; d  
sFileName = value; \##zR_%  
} .bl/*s  
Jl8H|<g~/  
/ y40(l?  
public int getNSplitter() yNJ B oar  
{ gnf8l?M  
return nSplitter; [ZwjOi:)  
} wc@X.Q[  
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&ee~p&S,>  
public void setNSplitter(int nCount) hp50J  
{ e(;,`L\*  
nSplitter = nCount; z]y.W`i   
} ~8Fk(E_  
} =!A_^;NQf  
%g$o/A$  
^$jb7HMObI  
/* {%5eMyF#  
**Utility.java ?3`UbN:  
*/ :K,i\  
package NetFox; T@B/xAq5!  
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9MJG;+B~  
public class Utility { 2%Ri,4SRb  
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public Utility() 3AtGy'NTp  
{ rl;
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K&]G3W%V  
} Hyl%mJ  
.p3,O6y2(F  
//线程睡眠 3BJ0S.TF  
public static void sleep(int nSecond) Xza(k  
{ (*'f+R`$  
try{ *I.f1lz%*  
Thread.sleep(nSecond); ORw,)l  
} S!CC }3zw  
catch(Exception e) WIxy}3_to  
{ qS$Ox?Bw#u  
e.printStackTrace (); (NU NHxi5B  
} !>&o01i  
} `5.'_3  
Qx#"q'2  
//日志 ql{OETn#  
public static void log(String sMsg) |v%YQ R  
{ %)W2H^  
System.err.println(sMsg); &)ChQZA  
} U(g:zae  
L|xbR#v  
0RLg:SV  
public static void log(int sMsg) {rw|#Z>A  
{ &%DY\*  
System.err.println(sMsg); ;bib/  
} 8qTys8  
} dn
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s};{ZAtE  
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/* K=k"a  
**TestMethod.java n
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*/ }2.`N%[  
package NetFox; WX?IYQ+  
k$R-#f;  
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public class TestMethod { HCs?iJ  
$a"Oc   
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public TestMethod() 1};Stai'  
{ ///xx/weblogic60b2_win.exe 9}<ile7^  
try{ <0&*9ZeD  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xF'EiX~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); E A1?)|}n  
SiteFileFetch fileFetch = new SiteFileFetch(bean); WiR(;m<g  
fileFetch.start(); ]72`};  
} *zvx$
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catch(Exception e){e.printStackTrace ();} (exa<hh  
b9HtR-iR;  
6j]0R*B7`Q  
} ]MitOkX  
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public static void main(String[] args) VU
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{ |N7M^  
new TestMethod(); N +_t-5  
} xy[3u?,&s!  
} | rtD.,m   
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