http断点续传简单实现（java)

/* [|.IXdJ!  
**SiteFileFetch.java ^YiGvZJ  
*/ jfF   
package NetFox; G<:_O-cPSv  
import java.io.*; %/iD@2r  
import java.net.*; ova4  
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public class SiteFileFetch extends Thread {  ~ "Xcd8:  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 0vR gmn  
long[] nStartPos; //开始位置 }@6ws/5  
long[] nEndPos; //结束位置 Pfi|RTX$'*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +
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long nFileLength; //文件长度 a|S6r-_;s  
boolean bFirst = true; //是否第一次取文件 pDqX% $^  
boolean bStop = false; //停止标志 !1(*D*31  
File tmpFile; //文件下载的临时信息 L8R{W0Zr>!  
DataOutputStream output; //输出到文件的输出流 ?TTtGbvU  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） b?i5C4=K  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0])D)%B k  
{ Bl[4[N  
siteInfoBean = bean; /5M0[C E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); b$FK}D5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F/p/&9  
if(tmpFile.exists ()) )<YfLDgTs  
{ -4wr)zjfW  
bFirst = false; s R/z)U_  
read_nPos(); V9`?s0nn^  
} gOb"-;Zw  
else BV;dV6`z  
{ t^Z-0jH  
nStartPos = new long[bean.getNSplitter()]; kA/4W^]Ws  
nEndPos = new long[bean.getNSplitter()]; pNUe|b+P  
} b:B+x6M  
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} cvOCBg38BH  
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public void run() !%X~`&9  
{ nIZ;N!r=i  
//获得文件长度 d
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//分割文件 hufpky[&8  
//实例FileSplitterFetch ICdfak  
//启动FileSplitterFetch线程 pTeN[Yu?  
//等待子线程返回 2P,%}Ms  
try{ 2`dKnaF|  
if(bFirst) C*X=nezq  
{ ibP IT!5c  
nFileLength = getFileSize(); !#y_
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if(nFileLength == -1) +-X 68`  
{ ,{6Vf|?  
System.err.println("File Length is not known!"); )x5t']w`K  
} 4yK{(!&i+  
else if(nFileLength == -2) +L0Jje>Az  
{ f/PqkHF  
System.err.println("File is not access!"); N=T 0Td  
}
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else e@h(Zwp  
{ h-.xx4D  
for(int i=0;i<nStartPos.length;i++)  ^t}1$H  
{ Lm&BT)*  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l4bLN  
} po9f[/s'+o  
for(int i=0;i<nEndPos.length-1;i++) _.%U}U  
{ [_HY6gr  
nEndPos = nStartPos[i+1];
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} =O%Hf bx  
nEndPos[nEndPos.length-1] = nFileLength; G!)Q"+  
} ;~,)6UX7  
} +lplQ
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//启动子线程 [
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b^:frjaE3  
for(int i=0;i<nStartPos.length;i++) ^]5^p9Jt"e  
{ k3+LP7|*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0gRm LX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1'B&e)  
nStartPos,nEndPos,i); )TfX}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 70<{tjyc  
fileSplitterFetch.start(); ,Dab(  
} ??#SQSU  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V_3K((P6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _I?oR.ON33  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", gb{8SG5ac  
nEndPos = " + nFileLength); :\Q#W4~p  
// fileSplitterFetch[nPos.length-1].start(); e_YTh^wU  
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//等待子线程结束 7#&e0fw/I  
//int count = 0; 8S` j6  
//是否结束while循环 ;w7s>(ITZ  
boolean breakWhile = false; h_HPmh
5  
mY[*(a  
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while(!bStop) (u4'*[o\t  
{ -}1TT@  
write_nPos(); MWv(/_b  
Utility.sleep(500); dY{qdQQ}  
breakWhile = true; 8 =oUE$9  
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for(int i=0;i<nStartPos.length;i++) Mt4*`CxtH;  
{ k:F{U^!p|  
if(!fileSplitterFetch.bDownOver) [sNvCE$\]  
{ @#=yC.s  
breakWhile = false; *C);IdhK%y  
break; Tb:6IC7="  
} ~ o=
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} U7''; w  
if(breakWhile) Zi?:< H}  
break; 2>[xe  
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iA<'i8$P  
//count++; R=<%!  
//if(count>4) 4,08`5{  
// siteStop(); =9h!K:,k  
} ]O>AD6P  
mp)+wZAN&  
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System.err.println("文件下载结束！"); v\@pZw=x  
} Jj/}GVNc7  
catch(Exception e){e.printStackTrace ();} y=0)vi{]  
} GExr] 2r  
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;|`<B7xf  
//获得文件长度 }eF r,bJ  
public long getFileSize() u#y#(1 =  
{ ,D'm#Fti  
int nFileLength = -1; .D;6 r4S  
try{ 9}_'  
URL url = new URL(siteInfoBean.getSSiteURL()); i;atYltEJ2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &e78xtA{  
httpConnection.setRequestProperty("User-Agent","NetFox"); X~cdM1z?  
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int responseCode=httpConnection.getResponseCode(); JZK93R  
if(responseCode>=400) M0g=gmau  
{ +|x{?%
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processErrorCode(responseCode); s(?%A  
return -2; //-2 represent access is error (I`lv=R"j  
} l<p<\,nV$  
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String sHeader; K$:+]fJK  
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for(int i=1;;i++) F2\&rC4v  
{ 3IJ0 P.x!o  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6Xz d>5x  
//Utility.log(in.readLine()); 0@[*~H
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sHeader=httpConnection.getHeaderFieldKey(i); t\h4-dJn  
if(sHeader!=null) r{B28'f[  
{ 5F!Qn\{u{  
if(sHeader.equals("Content-Length")) *o38f>aJl  
{ B`t/21J  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); MN8>I=p  
break; g*(z.  
} & Zn`2%  
} C\joDAD  
else b;{"@b,Y  
break; 97UOH  
} 3HBh 3p5  
} f,F1k9-1!  
catch(IOException e){e.printStackTrace ();} :p,|6~b$  
catch(Exception e){e.printStackTrace ();} PO8Z2"WI  
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Utility.log(nFileLength); tjwnFqI  
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}]  
return nFileLength; Vfga%K%l F  
} vy}_aD{B  
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//保存下载信息（文件指针位置） !tt 8-Y)i  
private void write_nPos() Pc=ei  
{ 4].o:d;`/  
try{ Lui6;NY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U65l o[  
output.writeInt(nStartPos.length); deArH5&!  
for(int i=0;i<nStartPos.length;i++) uS,?oS  
{ CuH4~6  
// output.writeLong(nPos); [5p3:D  
output.writeLong(fileSplitterFetch.nStartPos); <" nWGF4d  
output.writeLong(fileSplitterFetch.nEndPos); /FE+WA}r  
} "acI:cl?,  
output.close(); R6BbkYWrX  
} #h^nvRmON  
catch(IOException e){e.printStackTrace ();} Tx~w(A4:  
catch(Exception e){e.printStackTrace ();} v@
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} Za1mI^ L1  
S*=^I2;  
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//读取保存的下载信息（文件指针位置） R[
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private void read_nPos() W{.:Cf9  
{ yna!L@ *@,  
try{ y>x"/jzF#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ] 1pIIX}  
int nCount = input.readInt(); LwRzzgt  
nStartPos = new long[nCount]; }=)u_q  
nEndPos = new long[nCount]; jvsSP?]n  
for(int i=0;i<nStartPos.length;i++) Be]z @E1x  
{ l"E{ ?4  
nStartPos = input.readLong(); b#p0s?*  
nEndPos = input.readLong(); lAM)X&}0  
} HBR/" m  
input.close(); &Pm@+ML*x  
} |(*btdqy3  
catch(IOException e){e.printStackTrace ();} 8v2Wi.4T  
catch(Exception e){e.printStackTrace ();} ?i0+h7=6  
} L`K)mCr  
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private void processErrorCode(int nErrorCode) eA
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{ r3U7`P   
System.err.println("Error Code : " + nErrorCode); 4cSs=|m?+  
} h ChO  
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//停止文件下载 w9GY/]  
public void siteStop() 8A]8yX =  
{ AJLzLb
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bStop = true; #aC&!Rei{  
for(int i=0;i<nStartPos.length;i++) 5OGwOZAj52  
fileSplitterFetch.splitterStop(); G@D;_$a  
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}0E@eL  
} hlV(jz  
} |tI{MztJ"c  
//负责部分文件的抓取 k7*-v/*S  
**FileSplitterFetch.java rjc
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*/ "gI-S[  
package NetFox; Q$.CtECo  
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import java.io.*; {)r[?%FMgV  
import java.net.*; 4%nK0FAj  
g=4P-i3  
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public class FileSplitterFetch extends Thread { Om:Gun\%  
1iR\M4?Frf  
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String sURL; //File URL K ~\b+  
long nStartPos; //File Snippet Start Position qfFa" a  
long nEndPos; //File Snippet End Position i`CNgScF>  
int nThreadID; //Thread's ID N|>MqH,Bt  
boolean bDownOver = false; //Downing is over ;MYK TE>m  
boolean bStop = false; //Stop identical aRWj+[[7y  
FileAccessI fileAccessI = null; //File Access interface ?cz7s28a  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :+_H
%4+  
{ Z] cFbl\ma  
this.sURL = sURL; ]OKKR/:  
this.nStartPos = nStart; GPs4:CIgG  
this.nEndPos = nEnd; .ejC#vB{KM  
nThreadID = id; "0G)S'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mp(:D&M  
} r7U[QTM%  
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public void run() ^JIs:\g<<  
{ 'g)5vI~'  
while(nStartPos < nEndPos && !bStop) #CeWk$)m  
{ REJBm  
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try{ ABtv|0K  
URL url = new URL(sURL); JKYl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3=L5Y/  
httpConnection.setRequestProperty("User-Agent","NetFox"); IU}g[OCu  
String sProperty = "bytes="+nStartPos+"-"; 1RQM-0W,  
httpConnection.setRequestProperty("RANGE",sProperty); ^?0WE  
Utility.log(sProperty); G8W^XD  
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InputStream input = httpConnection.getInputStream(); +{e2TY  
//logResponseHead(httpConnection); 8+_e=_3R  
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byte[] b = new byte[1024]; R/c-sV  
int nRead; +N:M;uTS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a,*|*Cv  
{ eNt1P`2[  
nStartPos += fileAccessI.write(b,0,nRead); ZoKXao  
//if(nThreadID == 1) @F5QgO J&r  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YQfQ[{kp  
} }cy<$=c#E_  
7}e{&\0=l  
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Utility.log("Thread " + nThreadID + " is over!"); {f%x8t$  
bDownOver = true; dy0xz5N-  
//nPos = fileAccessI.write (b,0,nRead); uchz<z1  
} :+S~N)0j^  
catch(Exception e){e.printStackTrace ();} 0',-V2  
} #>\8m+h 9  
} v/7iu*u  
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:,dO7dJi  
//打印回应的头信息 ApAHa]Ccp  
public void logResponseHead(HttpURLConnection con) 2Yd;#i)  
{ {{4Sgb  
for(int i=1;;i++) {W#VUB  
{ #]o#~:S=  
String header=con.getHeaderFieldKey(i); Jro%zZle  
if(header!=null) v4x1=E  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); yB^_dE  
Utility.log(header+" : "+con.getHeaderField(header)); c3aF lxW  
else K0?:?>*b#  
break; f9&po2Pzf  
} |/35c0IM  
} y 4jelg  
SA16Ng  
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public void splitterStop() &!FWo@  
{ ?wS/KEl=O  
bStop = true; q]o^Y  
} ( u}tUv3  
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} B mxBbg  
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/* HBnnIbEtF'  
**FileAccess.java onAC;<w  
*//文件访问(定位，写) okZDxg`6  
package NetFox; VM[Vhk[  
import java.io.*; %CiZ>`5n#  
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4#y  
public class FileAccessI implements Serializable{ n~NOqvT <  
a5xp[TlXn.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `[Xff24(eb  
RandomAccessFile oSavedFile; 07L1 "  
long nPos; /"<o""<]  
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public FileAccessI() throws IOException ;4 ON  
{ gNG_,+=!  
this("",0); ]RJcY1  
} 5 J9,/M0  
)9QeVf  
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public FileAccessI(String sName,long nPos) throws IOException ]2P*Z6Az  
{ L.@o  
oSavedFile = new RandomAccessFile(sName,"rw"); ,2YkQ/>  
this.nPos = nPos; KDX34Fr1  
oSavedFile.seek(nPos); \{ui{8+G  
} nZ 0rxx[V?  
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L(2KC>GvA  
public synchronized int write(byte[] b,int nStart,int nLen) %kJ_o*"  
{ JW4~Qwx  
int n = -1; MdOQEWJ$|  
try{ 5L}qL?S`x|  
oSavedFile.write(b,nStart,nLen); zLxO\R!d  
n = nLen; o4"7i 9+g  
} M1/Rba Q  
catch(IOException e) q-fxs8+m|  
{ ( o_lH2  
e.printStackTrace (); !5P\5WF~Y  
} 75LIQ!G|=  
/i#~#Bn|  
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return n; T.sib&R  
} *3A[C-1~.  
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} OA_Bz"  
#;32(II  
o7*z@R"  
/* ]HK|xO(  
**SiteInfoBean.java zMkjdjb  
*/ BQcrF{
q  
package NetFox; yqm^4)Dp  
<I{)p;u1  
aD1G\*AFJ  
public class SiteInfoBean { W~J>Srt  
-4&SYCw  
f"j"ZM{~U  
private String sSiteURL; //Site's URL :i&ZMH,O  
private String sFilePath; //Saved File's Path Lii,L}  
private String sFileName; //Saved File's Name \lnpsf  
private int nSplitter; //Count of Splited Downloading File Ls#=R  
]iyJ>fC  
#mNM5(o  
public SiteInfoBean() i%8I (F  
{//nSplitter的缺省值为5 w>:~Ev]  
//default value of nSplitter is 5 ]e'Ol$3U9=  
this("","","",5); "?Eh_Dw  
} n\#RI9#\  
\/J7U|@Lt  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F8J;L]
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{ 8v},&rhPQq  
sSiteURL= sURL; \o-Q9V  
sFilePath = sPath; 1Y"[Qs]"mU  
sFileName = sName; v(T;Y=&  
this.nSplitter = nSpiltter; ^gwVh~j  
]}_@!F)  
J?WT  
} Z^w}: {  
p#9.lFSX  
+)#d+@-  
public String getSSiteURL() P~V0<$C  
{ q^ {Xn-G  
return sSiteURL; pv.
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} =gCv`SFW  
bY4~\cP.  
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public void setSSiteURL(String value) jJc?/1jv  
{ HG2i^y  
sSiteURL = value; =y; tOdj
  
} )S
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]>NP?S )R  
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public String getSFilePath() Ixhe86-:T  
{ OXy>Tlv  
return sFilePath; 5eI3a!E]O  
} }LDH/# u  
t{\FV@R  
_cqBp7  
public void setSFilePath(String value) VjbRjn5LI  
{ _ECWSfZ  
sFilePath = value;
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} NJfI9L  
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b[<zT[.:  
public String getSFileName() U^trZ])  
{ fRp+-QvE  
return sFileName; 58"Cn ||tF  
} sW[8f Z71  
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public void setSFileName(String value) D2o,K&
V  
{ HS"E3s8  
sFileName = value; o}&TFhT  
} 5;wA7@  
29DYL  
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public int getNSplitter() a?bSMt}  
{ R[Q`2ggG  
return nSplitter; ~|e?@3_G  
} 7iCH$}  
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B#Rw
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public void setNSplitter(int nCount) Az.(tJ X"  
{ b/IT8Cm3  
nSplitter = nCount; 8?ldD  
} h2g|D(u)  
} 0d!1;jy,T  
<[O8{9j  
h#Cq-^D#~  
/* %~uMa  
**Utility.java W]kh?+SZ  
*/ ".jY3<bQg  
package NetFox; h|h-<G?>  
4.)
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public class Utility { ?I{pv4G:  
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#L[-WC]1y  
public Utility() 0PIiG-o9  
{ f`w$KVZ1!w  
1"J\iwN3  
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} `2X~3im  
c e`3&  
//线程睡眠 >[TB8  
public static void sleep(int nSecond) ("(:wYR%  
{ >%jQw.  
try{ d#yb($HAJ  
Thread.sleep(nSecond); MxMrLiqU6l  
} / sI0{  
catch(Exception e) B0Ql1x#x  
{ C%8nr8po  
e.printStackTrace (); >5C|i-HX  
} smEKQHB  
} rW$ )f  
CAg\-*
P|  
//日志 P?%kV  
public static void log(String sMsg) !yAg!V KY  
{ ,c#IxB/0  
System.err.println(sMsg); pE{ZWW[@+  
} Bw2-4K\"kc  
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public static void log(int sMsg) siveqz6
h  
{ 8T
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System.err.println(sMsg); 1F`1(MYt9  
} C
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} 9!C
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W=zHD9  
/* v|DgRPY  
**TestMethod.java zfS0
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*/ Y3%_IwSJ|  
package NetFox; Tj0qq.
 
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l@
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public class TestMethod { lX g.`  
#)A.yK`u  
e`]x?t<U4/  
public TestMethod() K
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{ ///xx/weblogic60b2_win.exe _JEe]  
try{ Whd.AaD\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); z89
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zDakl*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %%uvia=e  
fileFetch.start(); ,> %=,x
 
} TwdY6E3`  
catch(Exception e){e.printStackTrace ();} eMHBY6<~=  
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9(-f)$u  
} >`E (K X  
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public static void main(String[] args) g"}j  
{ \+iZdZD  
new TestMethod(); ) dB?Ep|  
} _P}wO8  
} i>j(Dsv  
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