http断点续传简单实现（java)

/* -!d'!; ]  
**SiteFileFetch.java kg0X2^#b  
*/ 2% ],0,o  
package NetFox; @\{L%y%a0  
import java.io.*; bYsK|n  
import java.net.*; vTE3-v[i  
 UZJ^e$N  
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public class SiteFileFetch extends Thread { +qN}oyL  
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SiteInfoBean siteInfoBean = null; //文件信息Bean N{/):O  
long[] nStartPos; //开始位置 0j{Rsy  
long[] nEndPos; //结束位置 Kkfza  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Dnx` !  
long nFileLength; //文件长度 An0DqjR  
boolean bFirst = true; //是否第一次取文件 #bI,;]T  
boolean bStop = false; //停止标志 S F:>dneB  
File tmpFile; //文件下载的临时信息 RCZ"BxleU  
DataOutputStream output; //输出到文件的输出流 18*M  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 244[a] %&;  
public SiteFileFetch(SiteInfoBean bean) throws IOException nZtMF%j'  
{ \kN?7b^  
siteInfoBean = bean; B/Jz$D  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |
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if(tmpFile.exists ()) <8J_[ S  
{ k
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bFirst = false; |B{@noGX  
read_nPos(); L0lqm0h  
} e4h9rF{Cxn  
else a:v5(@8  
{ ` x|=vu-  
nStartPos = new long[bean.getNSplitter()]; Z]~) ->=}  
nEndPos = new long[bean.getNSplitter()]; `;~A  
} I$0O4  
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} &~Hx!]uc  
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public void run() [_B
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{ ;
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//获得文件长度 y2`},  
//分割文件 TCWt3\  
//实例FileSplitterFetch K[
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//启动FileSplitterFetch线程 ;T\+TZtI  
//等待子线程返回 zJ*(G_H  
try{ jk\z-hd
 
if(bFirst) \{EYkk0]  
{ >vPv4e7&3  
nFileLength = getFileSize(); ?hmuAgOtbh  
if(nFileLength == -1) cjp~I/U  
{ ~K/_51O'  
System.err.println("File Length is not known!"); gyz_$
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} ,,c+R?D  
else if(nFileLength == -2) =]fOQN`  
{ }&LVD$Bz  
System.err.println("File is not access!"); e>T;'7HSS"  
} (V x2*Aw]  
else HO_!/4hrU  
{ LgxsO:mi  
for(int i=0;i<nStartPos.length;i++) dQs>=(|t  
{ #&}j'oD|N  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); at+Nd K  
} )^`V{iD  
for(int i=0;i<nEndPos.length-1;i++) K>vi9,4/ks  
{ _iF*BnmN  
nEndPos = nStartPos[i+1]; .TM. v5B  
} d:Oo5t)MN  
nEndPos[nEndPos.length-1] = nFileLength; YS
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} UOpSH{N  
} ~l8w]R3A  
9|WV28PK:  
4YSVy2x  
//启动子线程 \iRmGvT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ZmDM
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for(int i=0;i<nStartPos.length;i++) f hjlt#  
{ MCAWn H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t3b M4+n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \1O wZ@  
nStartPos,nEndPos,i); P=aYwmC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Iw4[D#o  
fileSplitterFetch.start(); ?PYZW5  
} NY6;\ 7!n  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "/ySHB[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", AqAL)`#K  
nEndPos = " + nFileLength); {%\@Z-9%q,  
// fileSplitterFetch[nPos.length-1].start(); +NJIi@  
,e^~(I
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?kK3%uJy&  
//等待子线程结束 'YJ~~o  
//int count = 0; KF6N P  
//是否结束while循环 ~3Za"q*0s  
boolean breakWhile = false; Y!`pF  
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while(!bStop) 'jXJ!GFw  
{ ?OPuv5!pI  
write_nPos(); @?jbah
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Utility.sleep(500); azzG  
breakWhile = true; oE_*hp+  
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for(int i=0;i<nStartPos.length;i++) O6,2M[a  
{ [a
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if(!fileSplitterFetch.bDownOver) ,rjl|F* T  
{ )%b 5uZ  
breakWhile = false; !*3]PZ25a(  
break; *+k yuY J  
} Z^BZH/I?  
} If]rg+|U  
if(breakWhile) 1>/ iYf  
break; ^oYRBEIJH  
|S~$IFN4  
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//count++; 
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//if(count>4) zf]e"e  
// siteStop(); \=P(?!v  
} M(yWE0 3  
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System.err.println("文件下载结束！"); $ce*W9`  
} vL;>A]oM2  
catch(Exception e){e.printStackTrace ();} N]14~r=  
} c^cr_i  
\D};0#G0&  
|26[=_[q  
//获得文件长度 YNl".c  
public long getFileSize() ,)N/2M\B-  
{ vRn]u57O  
int nFileLength = -1; |3~]XN-  
try{ w ~"%&SNN  
URL url = new URL(siteInfoBean.getSSiteURL()); Sb?Ua*(L:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L7nG5i  
httpConnection.setRequestProperty("User-Agent","NetFox"); >$yA ,N  
?Q$a@)x#  
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int responseCode=httpConnection.getResponseCode(); c<lEFk!g
 
if(responseCode>=400) R^=v&c{@  
{ O,-NzGs  
processErrorCode(responseCode); Um4DVg5  
return -2; //-2 represent access is error $RB p!7  
} Qg]A^{.1  
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>  
String sHeader; fFoZ!H  
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for(int i=1;;i++) |H]0pbC)w  
{ ,KD?kSIf  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); y"s
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//Utility.log(in.readLine()); WbBd<^Q  
sHeader=httpConnection.getHeaderFieldKey(i); 49<t2^1q  
if(sHeader!=null) Ml;` *;  
{ C@\5%~tW+  
if(sHeader.equals("Content-Length")) lzz;L z  
{ NZ0?0*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); D%LYQ  
break; 8h4]<T  
} * hS6F  
} `m8WLj  
else ~t/i0pKq.  
break; ^ERdf2  
} \x\N?$`ANc  
} =yM%#{t&W  
catch(IOException e){e.printStackTrace ();} j_~mP>el)  
catch(Exception e){e.printStackTrace ();} Cz$q"U  
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}@ktAt  
Utility.log(nFileLength); vceD/N8  
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return nFileLength; 5o>*a>27,A  
} Iz-mUD0;  
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6Z'K1  
//保存下载信息（文件指针位置）
6,M$TA  
private void write_nPos() 2/tx5Nc  
{ -Ah&|!/  
try{ \=
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output = new DataOutputStream(new FileOutputStream(tmpFile)); U<q`f-  
output.writeInt(nStartPos.length); zK1]o-wSAT  
for(int i=0;i<nStartPos.length;i++) %.]#3tW  
{ f-|zh#L  
// output.writeLong(nPos); ^k$Bx_{  
output.writeLong(fileSplitterFetch.nStartPos); 3A[<LnKR^E  
output.writeLong(fileSplitterFetch.nEndPos); :dRC$?f4  
} bJ1Nf|3~E  
output.close(); S w%6-  
} %G,7Ul1f  
catch(IOException e){e.printStackTrace ();} yzT1Zg_ER  
catch(Exception e){e.printStackTrace ();} IbL'Z   
} :).NA ]  
_j3rs97@|  
2 'D,1F  
//读取保存的下载信息（文件指针位置） 44B D2`nF  
private void read_nPos() $F9w0kz:,*  
{ jF j'6LT9/  
try{
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); WQze|b%  
int nCount = input.readInt(); IGVq`Mxj  
nStartPos = new long[nCount]; 3!/J!X3L  
nEndPos = new long[nCount]; G3+e5/0  
for(int i=0;i<nStartPos.length;i++) 5
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{ ~<O.Gu&"R  
nStartPos = input.readLong(); &"gX 7cK8  
nEndPos = input.readLong(); *i#N50k*j'  
} U
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input.close(); Q&w_kz.  
} 4&%H;Q  
catch(IOException e){e.printStackTrace ();} 2|i
1}  
catch(Exception e){e.printStackTrace ();} rP2h9Cb  
} D|m0Vj b  
);TB(PQsBT  
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private void processErrorCode(int nErrorCode) #W|Obc]K  
{ "=C~IW  
System.err.println("Error Code : " + nErrorCode); xmDX1sL**  
} G=8w9-Ww  
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//停止文件下载 I@=h|GM  
public void siteStop() X'&$wQ6,K  
{ TgaDzF,j{A  
bStop = true; {tE/Jv $  
for(int i=0;i<nStartPos.length;i++) jz[|rwAp  
fileSplitterFetch.splitterStop(); lK^Q#td:`  
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} 8j,
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} f/b }X3K  
//负责部分文件的抓取 -?b@6U  
**FileSplitterFetch.java >EMgP1  
*/ 0NSn5Hq  
package NetFox; $p4aNC  
|zu>G9m  
K)qbd~<\  
import java.io.*; sQ^>.yG  
import java.net.*; Y\T*8\h_[  
'D-#,X C  
&F}1\6{fL  
public class FileSplitterFetch extends Thread { &bJ98Nxl  
=3=KoH/'  
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String sURL; //File URL F.=uJdl.!  
long nStartPos; //File Snippet Start Position 'KGY;8<x]  
long nEndPos; //File Snippet End Position e![Q1!r  
int nThreadID; //Thread's ID lq@Vb{Z  
boolean bDownOver = false; //Downing is over [&*$!M  
boolean bStop = false; //Stop identical {K'SOhH4?  
FileAccessI fileAccessI = null; //File Access interface wN)R !6  
|4Ix2GD  
b
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ABV\:u  
{ ,l<-*yMD  
this.sURL = sURL; z1+rz%  
this.nStartPos = nStart; FGx_qBG4|  
this.nEndPos = nEnd; 4Uf+t?U9  
nThreadID = id; e#^|NQ<'A  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 v%<_Mh  
} fC3IxlG  
s/[i>`g/9  
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public void run() =X X_Cnn  
{ 1TQ$(bI  
while(nStartPos < nEndPos && !bStop) Kc udWW]  
{ 8{+~3@T  
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try{ b=T+#Jb  
URL url = new URL(sURL); VP4t~$"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |->y'V  
httpConnection.setRequestProperty("User-Agent","NetFox"); UKK}$B  
String sProperty = "bytes="+nStartPos+"-"; &SN$D5U'  
httpConnection.setRequestProperty("RANGE",sProperty); (P#2Am$  
Utility.log(sProperty); b+p!{  
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InputStream input = httpConnection.getInputStream(); W,{`)NWg  
//logResponseHead(httpConnection); Y)u}+Yg  
 (+]k{  
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byte[] b = new byte[1024]; Aq'%a)Y2  
int nRead; IPxfjBC+J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >qF KXzI  
{ $PS5xD~@  
nStartPos += fileAccessI.write(b,0,nRead); T (2,iG8  
//if(nThreadID == 1) .hJ8K#r  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aY:(0en]&  
} @$+[IiP  
6$6NVq  
,;d9uG2  
Utility.log("Thread " + nThreadID + " is over!"); J/<`#XZB   
bDownOver = true; `f'
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//nPos = fileAccessI.write (b,0,nRead); *>'R R<  
} "tj#P  
catch(Exception e){e.printStackTrace ();} ^p7(  
} b/K&8C,c  
} GC\/B0!  
)(L&+
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QNJG}Upl  
//打印回应的头信息 ?@#}%<yEq  
public void logResponseHead(HttpURLConnection con) :9h8q"T  
{ kTk?[BK  
for(int i=1;;i++) O(~Vvoq  
{ /*O,T  
String header=con.getHeaderFieldKey(i); Azle ;\l`  
if(header!=null) rka:.#!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ur-^X(nL  
Utility.log(header+" : "+con.getHeaderField(header)); *"CvB{XF&Z  
else ;?o C=c  
break; d$TW](Bby  
} )g --=w3  
} UJH{vjIv  
#CS>A#Lk  
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public void splitterStop() 0&\Aw'21  
{ J7_H.RPa  
bStop = true; o/zCXZnw#  
} 709eLhXrH  
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$;CC lzw  
} ?},ItJ#>)q  
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ZYsFd_  
/* ger<JSL%  
**FileAccess.java yx
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*//文件访问(定位，写) 6b/b}vl  
package NetFox; jVINc=o  
import java.io.*; 3I5WD
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C'._}\nX  
1,j9(m2  
public class FileAccessI implements Serializable{ 4iz&"~&1  
x
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +_eb*Z`5o  
RandomAccessFile oSavedFile; \Wc/kY3&  
long nPos; gn"&/M9E  
i'wF>EBz  
r(i)9RI+(  
public FileAccessI() throws IOException ^I{]Um:  
{ u =kSs  
this("",0); 2]9<%-=S  
} *?D2gaCta  
n6G&^Oj  
 ^qqHq  
public FileAccessI(String sName,long nPos) throws IOException i8YgG0[)  
{ a{*'pY(R0$  
oSavedFile = new RandomAccessFile(sName,"rw"); l _O~v?  
this.nPos = nPos; 6B/"M-YME  
oSavedFile.seek(nPos); @izi2ND  
} *'YNRM\}  
ZPsY0IzLo  
]zU<=b@  
public synchronized int write(byte[] b,int nStart,int nLen)  #>jH[Q  
{ ,R}KcZG)  
int n = -1; TDIOK  
try{ htYrv5q=M  
oSavedFile.write(b,nStart,nLen); '1'1T5x~  
n = nLen; `U_>{p&x  
} 6Y)^)dOi  
catch(IOException e) )75yv<L2S,  
{ S1juAV=  
e.printStackTrace (); DG*o w^  
} 4VJzs$  
L*01l"
5  
;9p5YxD  
return n; `$Flgp0P  
} fC GDL6E  
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} E'S;4B5?  
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/* `V):V4!j),  
**SiteInfoBean.java 8^/Ek<Qb|  
*/ x]><}!\<&  
package NetFox; W/r?0E  
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public class SiteInfoBean { Be>c)90bO_  
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private String sSiteURL; //Site's URL W[X!P)=w]  
private String sFilePath; //Saved File's Path a
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9  
private String sFileName; //Saved File's Name e|5B1rMM  
private int nSplitter; //Count of Splited Downloading File <aSLm=  
/>^`*e_  
-=Eq/su%  
public SiteInfoBean() iWN.3|r  
{//nSplitter的缺省值为5 t:"=]zUU  
//default value of nSplitter is 5 _/%]:  
this("","","",5); v`+n`DT  
} ^,Y~M_=  
fyg~KF}  
)_Xxk_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (m3I#L  
{ ~0[G/A$]  
sSiteURL= sURL; !w#ru?L{  
sFilePath = sPath; x#F1@r8R  
sFileName = sName; V>>) 7E:Q  
this.nSplitter = nSpiltter; }OP%p/eY  
qSC~^N`  
!skb=B#  
} cGpN4|*rQ  
nd
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<^*+8{*  
public String getSSiteURL() Bgk~R.
l  
{ m
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return sSiteURL; y\|-O<8O  
} C:s^s  
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public void setSSiteURL(String value) Z}LOy^TL  
{ VeD+U~ d  
sSiteURL = value;  J:~[j  
} &3 XFgHo  
6cQeL$,SQ  
gc,J2B]61  
public String getSFilePath() _Qm7x>NT4  
{ x  tYV"  
return sFilePath; W>q*.9}Y"  
} %2Xus9;k#  
[$1: &!(!  
cYq']$]  
public void setSFilePath(String value) oRT  
{ HIPcZ!p  
sFilePath = value; n!kk~65|  
} kO..~@aY  
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public String getSFileName() @O}IrC!bf  
{ G!!-+n<  
return sFileName; o;M.Rt\A  
} zJnL<Q  
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public void setSFileName(String value) TZ&4  
{ .q5J^/kr  
sFileName = value; g{g`YvLu^  
} y+ 6`| h_  
#/n|@z'  
*1|YLy  
public int getNSplitter() _dYf  
{ Lf,CxZL5  
return nSplitter; (xk.NZnF  
} '2Q.~6   
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public void setNSplitter(int nCount) d'N(w7-Y  
{ Ij;==f~G  
nSplitter = nCount; Gt^|+[gD  
} s jL
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} ,~?A,9?%:  
8 *4@-3Sx  
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/* Ez06:]Jd  
**Utility.java +Od1)_'\D3  
*/ y;,=ajrF  
package NetFox; )LkM,T  
=8$|_  
/[\6oa  
public class Utility { ~v.jZ/h  
#5'c\\?Q  
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public Utility() ??%)|nj.  
{ X4d Xm>*?=  
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+90u!r^v  
} 9b?
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//线程睡眠 :~\LOKf  
public static void sleep(int nSecond) |$YyjYK  
{ T$:>*  
try{ WuBmdjZ  
Thread.sleep(nSecond); 17e=GL  
} mZ`1JO9  
catch(Exception e) VYL@RL'  
{ ]
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e.printStackTrace (); Vh 2Bz  
} [yO=S0 e  
} _aVJ$N.  
6{5q@9F  
//日志 " <<A  
public static void log(String sMsg) TcR=GR*cJ  
{ BmJkt3j."  
System.err.println(sMsg); q!ee g  
} Z+Kv+GmqH  
CT|z[^  
[m~b[ZwES  
public static void log(int sMsg) \|v`l{  
{ 2K3MAd{  
System.err.println(sMsg); E|Q{]&$;Z"  
} )\8URc|J  
} 3.(.*>  
|a%B|CX  
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/* [.{^"<Z<  
**TestMethod.java _~juv&  
*/ lco~X DI  
package NetFox; Q6u{@$(/N  
xM% pvx.'L  
^)|&|  
public class TestMethod { +yGY785b  
<}&7 a s  
-<|Y1PQ  
public TestMethod() DUqJ y*F(  
{ ///xx/weblogic60b2_win.exe t @;WgIp(&  
try{ I
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); RV}GK L>gn  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )^&,Dj  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;8BA~,4l  
fileFetch.start(); `ovgWv  
} 4b]_ #7Qm  
catch(Exception e){e.printStackTrace ();} 2%5?Fn=  
k'g$2  
c!mG1lwD.  
} }~rcrm.   
{H+?z<BF<  
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public static void main(String[] args) wEE2a56L-  
{ Vd21,~^>g  
new TestMethod(); <>]1Y$^Y
 
} inZi3@h)T  
} `YU=~xQ  
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