http断点续传简单实现（java)

/* &66-0d+Sh  
**SiteFileFetch.java "#Qqwsw7  
*/ ;~CAHn|Fe  
package NetFox; ve|ig]$5g<  
import java.io.*; `!V=~"ve  
import java.net.*; J$Uj@M  
{ }Q!./5  
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public class SiteFileFetch extends Thread { 5 YjqN  
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SiteInfoBean siteInfoBean = null; //文件信息Bean jrJ!A(<)  
long[] nStartPos; //开始位置 }TfZ7~o[  
long[] nEndPos; //结束位置 `=TV4h4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 P_6JweN  
long nFileLength; //文件长度 L?:.8k`d  
boolean bFirst = true; //是否第一次取文件 cih[A2lp  
boolean bStop = false; //停止标志 Q"rQVO  
File tmpFile; //文件下载的临时信息 PWUS@I  
DataOutputStream output; //输出到文件的输出流 zmaf@T
 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） T rK-XTev  
public SiteFileFetch(SiteInfoBean bean) throws IOException /&1FgSARK  
{ k;BXt:jDq  
siteInfoBean = bean; Z'=:Bo{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); PggjuPPh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [[ {L#  
if(tmpFile.exists ()) t,H=;U#  
{ jMFLd  
bFirst = false; G)5R iRcs  
read_nPos(); sKDsps^$  
} d7(g=JK<  
else uknX py))  
{ &gGh%:`B  
nStartPos = new long[bean.getNSplitter()]; 0G?*i_u\  
nEndPos = new long[bean.getNSplitter()]; +h*-9  
} EH1GdlhA  
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} GS_+KR\  
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public void run() 3(&f!<Uy  
{ <cig^B{nX  
//获得文件长度 _TLB1T^/4  
//分割文件 ArK%?*`5  
//实例FileSplitterFetch *BdKQ/Dk  
//启动FileSplitterFetch线程 f%ThS42  
//等待子线程返回 y@GqAN'DK[  
try{ L?h'^*F H}  
if(bFirst) }(MI
}o}  
{ #
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nFileLength = getFileSize(); Q6qIx=c4  
if(nFileLength == -1) {"e)Jj_=  
{ V7~tIhuJH  
System.err.println("File Length is not known!"); =o_Ua^mr  
} ;YGCsLT<xt  
else if(nFileLength == -2) RV@'$`Q  
{ ,76xa%k(U|  
System.err.println("File is not access!"); L'A9TW2  
} kfc5ra>&  
else `|rF^~6(dR  
{ zv.R~lMtY  
for(int i=0;i<nStartPos.length;i++) $tm%=g^  
{ @}{lp'8FYi  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); fGtYvl O-5  
} M0) q  
for(int i=0;i<nEndPos.length-1;i++) T5<851rH  
{ ue8"_N  
nEndPos = nStartPos[i+1]; PAYS~MnV@3  
} ctk~}(1#  
nEndPos[nEndPos.length-1] = nFileLength; Sj(5xa[  
} ]0dj##5tJ  
} ]wxjd l  
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//启动子线程 e #!YdXSx  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; GBg~NkC7.  
for(int i=0;i<nStartPos.length;i++) C srxi'Pe  
{ NpPuh9e{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j-$F@p_2F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `>1XL2  
nStartPos,nEndPos,i); \img   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'r0kX||  
fileSplitterFetch.start(); NB^+Hcb$  
} ojva~mnFf  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +`RQ^9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3u,CI!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _Jt  
nEndPos = " + nFileLength); Ea,L04K  
// fileSplitterFetch[nPos.length-1].start(); -xVp}RLT  
-Z(='A
 
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//等待子线程结束 )hy(0 D  
//int count = 0; w,)O*1't  
//是否结束while循环 d!P3<:+R[  
boolean breakWhile = false; 1-=ZIHW  
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/  
while(!bStop) *DUP$@}k  
{ =:"wU  
write_nPos(); gVscdg5  
Utility.sleep(500); :w,#RcW  
breakWhile = true; my]t[%Q{  
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}mdk+IEt  
for(int i=0;i<nStartPos.length;i++) })F.Tjf*  
{ fw3P?_4;*  
if(!fileSplitterFetch.bDownOver) )Vf!U"  
{ G4;5$YGG  
breakWhile = false; a\l?7Jr  
break; e0z(l/UB  
} 1=@csO_yn  
} 2 ":W^P  
if(breakWhile) 3 BQZ[%0@  
break; ?se\?q  
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JYw_Z*L=m  
//count++; b4?]/Uy+/  
//if(count>4) ^:cc3wt'3[  
// siteStop(); I<+i87=  
} /?Y]wY  
|MMaaW^"  
;@<Rh^g]  
System.err.println("文件下载结束！");
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} t9eEcqMg  
catch(Exception e){e.printStackTrace ();} H.)Y*zK0.  
} % B^BN|r  
T B(K&3_D  
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//获得文件长度 ]8+ D  
public long getFileSize() <L'6CBbP  
{ Q)[DSM  
int nFileLength = -1; qokCVI-\  
try{ ]tx/t^&/\u  
URL url = new URL(siteInfoBean.getSSiteURL()); YAP,#a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); HD_
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httpConnection.setRequestProperty("User-Agent","NetFox"); : *8t,f~s^  
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int responseCode=httpConnection.getResponseCode(); 3j7Na#<tL3  
if(responseCode>=400) @#QaaR;4  
{ `e[>S  
processErrorCode(responseCode); 7R7e3p,K  
return -2; //-2 represent access is error :*I='M9B  
} 3C gmZ7[  
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1smKU9B2)  
String sHeader; BVzMgn;  
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for(int i=1;;i++) ]|_UpP8EP  
{ =/e
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +~n4</  
//Utility.log(in.readLine()); :|a$[g5  
sHeader=httpConnection.getHeaderFieldKey(i); cH:9@>'$a  
if(sHeader!=null) Qf($F,)K  
{ gwyX%9  
if(sHeader.equals("Content-Length")) -!QVM\t  
{ ;DgQ8"f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =Cc]ugl7-  
break; (91 YHhk{  
} "lRxatM  
} e'|IRhr  
else \C<'2KZR,  
break; {|B 2$1':  
} S| |OSxZ  
} $d*PY_  
catch(IOException e){e.printStackTrace ();} j8)rz  
catch(Exception e){e.printStackTrace ();} xnOd$]  
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Utility.log(nFileLength); y>>)Yo&|  
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return nFileLength; kx,3[qe'S  
} 37b6w6{D  
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i`}!<
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//保存下载信息（文件指针位置） WBWIHv{j  
private void write_nPos() 8?hZ5QvA(j  
{ 8?N![D\@  
try{ QlMv_|`9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); K=1prv2  
output.writeInt(nStartPos.length); s`en8%  
for(int i=0;i<nStartPos.length;i++) ]E$bK  
{ watTV\b  
// output.writeLong(nPos); Vg~10Q  
output.writeLong(fileSplitterFetch.nStartPos); '{w[).c.  
output.writeLong(fileSplitterFetch.nEndPos); k=4C"   
} l5nm.i<M  
output.close(); zF@[S  
} qVW3oj<2  
catch(IOException e){e.printStackTrace ();} WK5B8u*<  
catch(Exception e){e.printStackTrace ();} lhX4MB"  
} >dJ[1s]  
4_
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//读取保存的下载信息（文件指针位置） RiZ)#0  
private void read_nPos() 22/"
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{ c_T+T
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try{ DQ@M?~1hp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); EXsVZg"#  
int nCount = input.readInt(); 'cqY-64CJZ  
nStartPos = new long[nCount]; SLz;5%CPV  
nEndPos = new long[nCount]; &2nICAN[  
for(int i=0;i<nStartPos.length;i++) L[^.pO  
{ sI6I5  
nStartPos = input.readLong(); 7+;.Q  
nEndPos = input.readLong(); M8R/a[ -A  
} "R\D:Olb#  
input.close(); 8g {;o7  
} 'p[*2J"K4  
catch(IOException e){e.printStackTrace ();} <v!jS=T  
catch(Exception e){e.printStackTrace ();}  7LB%7~{<  
} jx}7/  
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{:#c1d2@8  
private void processErrorCode(int nErrorCode) s"5
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{ pfR~?jYzm  
System.err.println("Error Code : " + nErrorCode); Lvrflx*Q  
} 2sj: &][R  
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RivhEc1h%  
//停止文件下载 ?{P$|:ha  
public void siteStop() 'Ck:=V%}g  
{ FX!Qd&kl1  
bStop = true; m@']%X*(,  
for(int i=0;i<nStartPos.length;i++) ?<
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fileSplitterFetch.splitterStop(); T
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a ?\:,5=  
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} Z<*"sFpAO  
} /9,y+"0SQz  
//负责部分文件的抓取 J!}\v=Rn  
**FileSplitterFetch.java :`>tCYy;  
*/ d@tf+_Ih  
package NetFox; +6x}yc:yd  
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import java.io.*; Jpc%i8  
import java.net.*; Jl1\*1"  
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public class FileSplitterFetch extends Thread { bYmk5fpRG  
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String sURL; //File URL Dw>)\\n{Kl  
long nStartPos; //File Snippet Start Position SW5n?Qj3-  
long nEndPos; //File Snippet End Position >[&ser  
int nThreadID; //Thread's ID d
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boolean bDownOver = false; //Downing is over )%<,JD  
boolean bStop = false; //Stop identical gD;T"^S+  
FileAccessI fileAccessI = null; //File Access interface bM2x (E\
O  
96S$Y~G#&  
!K+hXQE1  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1h#/8X  
{ HA0F'k  
this.sURL = sURL; 7jHrLsB  
this.nStartPos = nStart; :9e4(7~ona  
this.nEndPos = nEnd; ?mF:L"i  
nThreadID = id; @NL37C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1!yd(p=cL  
} )3O#T$h  
1]Cdfj6@  
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public void run() Mf !S'\  
{
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while(nStartPos < nEndPos && !bStop) o2;Eti  
{ i'10qWz  
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try{ TRJTJM_k  
URL url = new URL(sURL); M`7[hr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,Vl2U"   
httpConnection.setRequestProperty("User-Agent","NetFox"); )L7[;(gQ  
String sProperty = "bytes="+nStartPos+"-"; @ 'c(q=K;  
httpConnection.setRequestProperty("RANGE",sProperty); 2jlz#Sk  
Utility.log(sProperty); ;$8ptB.  
-d thY(8  
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InputStream input = httpConnection.getInputStream(); "a(e2H2&T4  
//logResponseHead(httpConnection); (zxL!ZR<  
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byte[] b = new byte[1024]; RCi8{~rIvS  
int nRead; 4"\x#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @BPQ >  
{ O S#RCN*  
nStartPos += fileAccessI.write(b,0,nRead);  w%::
~]  
//if(nThreadID == 1) Aar]eY\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ThkCKM  
} &gW<v\6,  
kd_!S[  
!T2{xmHKv$  
Utility.log("Thread " + nThreadID + " is over!"); $5\!ws<cZ  
bDownOver = true;
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//nPos = fileAccessI.write (b,0,nRead); !&cfX/y8  
} [k75+#'  
catch(Exception e){e.printStackTrace ();} =M9R~J!  
} 0l/7JH_@V  
} ?* r  
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`z.sWF|f!O  
//打印回应的头信息 >DbG )0|  
public void logResponseHead(HttpURLConnection con) 2^"!p;WQ  
{ kw} E0uY  
for(int i=1;;i++) j+S&5C/{  
{ *M$mAy<  
String header=con.getHeaderFieldKey(i); ^hr# 1  
if(header!=null) Ui-Y`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4=`1C-v?q  
Utility.log(header+" : "+con.getHeaderField(header)); X$G:3uoN  
else r\}?HS06  
break; etUfdZ  
} Pa#Jwo  
} X}5"ZLa7l  
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public void splitterStop() y|i(~  
{ r_FI5f  
bStop = true; u~VXe  
}  Hyenn  
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8G2QI4  
} M+^ NF\  
8zcSh/
 
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/* `:R9M+ OX  
**FileAccess.java ,_/\pX0  
*//文件访问(定位，写) O2yD{i#l*#  
package NetFox; wDSwcNS  
import java.io.*; v-^<,|vm2f  
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XR p60i6f  
public class FileAccessI implements Serializable{ lqgR4
!  
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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 TKbfZw  
RandomAccessFile oSavedFile; Tr4\ `a-i  
long nPos; Yt{Z+.;9OI  
5\O&pz@D  
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public FileAccessI() throws IOException gz uWhQo  
{ "pcr-
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this("",0); :8
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} &j/,8 Z*  
&~x|w6M]J  
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public FileAccessI(String sName,long nPos) throws IOException Snn4RB<(  
{ 3u 7A(  
oSavedFile = new RandomAccessFile(sName,"rw"); j|qdf3^f  
this.nPos = nPos; U#sv.r/L}3  
oSavedFile.seek(nPos); 69Z`mR  
} 7
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^^24a_+2  
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public synchronized int write(byte[] b,int nStart,int nLen) 0F6@aQ\y3  
{ |Q@(<'8=  
int n = -1; ftRdK>a D  
try{ =Lb(N61  
oSavedFile.write(b,nStart,nLen); /UY'E<wBx  
n = nLen; BT^=p  
} V\Y,4&bI  
catch(IOException e) UF\k0oLz  
{ EM1HwapD  
e.printStackTrace (); D8xE"6T>  
} Fo5UG2E&  
ACFE
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return n; !}c\u  
} a*_&[  

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} D vN0h(?  
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/* vXSA_"0t  
**SiteInfoBean.java QW_v\GHx  
*/ mq(K_  
package NetFox; "jq6FT)O  
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public class SiteInfoBean { !c0x^,iE  
.<YfnW5/K  
3RD+;^}q3  
private String sSiteURL; //Site's URL {A%&D^o)  
private String sFilePath; //Saved File's Path u@+^lRGFh  
private String sFileName; //Saved File's Name hOs~/bM  
private int nSplitter; //Count of Splited Downloading File .)1u0 (?
 
{}gL*2:EW$  
*IF~ab2  
public SiteInfoBean() $RHw6*COG  
{//nSplitter的缺省值为5 7C_U:x  
//default value of nSplitter is 5 Dr(;A>?qG  
this("","","",5); Ra^c5hP:.E  
} ycEp,V;[Z  
:9q|
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LW/> %  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) '~z`kah  
{ 1-<?EOYaE  
sSiteURL= sURL; !wKN
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sFilePath = sPath; jd"YaZOQ  
sFileName = sName; :;LaV  
this.nSplitter = nSpiltter; !>+m46A  
p^p1{%=  
hu}uc&N)iE  
} 
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public String getSSiteURL() 5l(@p7_+  
{ 7E?60^Tve  
return sSiteURL; -:Juxh  
} D*_.4I  
/R( .7N  
\9sJ`,T?  
public void setSSiteURL(String value) NjdDImz.;s  
{ hsQ*ozv[)  
sSiteURL = value; {t:*Xu  
} MQy,[y7I  
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k^s7s{  
public String getSFilePath() &##JZ  
{ Z^KWYe'w  
return sFilePath; YPw=iF]  
} %T;VS-f  
|+<o(Q(  
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public void setSFilePath(String value) c.>OpsF  
{ S6_dmTV*  
sFilePath = value; 0nR_I^  
} <4;L&3  
8lCo\T5"  
vv`53 Pbw)  
public String getSFileName() ;jlI>;C;V  
{ 2e({%P@2?  
return sFileName; #,!/Cnqis  
} !P
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public void setSFileName(String value) t-]~^s  
{ xp\6,Jyh  
sFileName = value; h<!!r  
} !\\1#:*_W  
3Z%jx#  
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public int getNSplitter() K#yCZ2  
{ WtMDHfwqu\  
return nSplitter; d#I; e  
} 8Urj;KkD  
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public void setNSplitter(int nCount) C33RXt$X  
{ ZM57(D  
nSplitter = nCount; 0!1cHB/c  
} ;PMy9H  
} 7q#R,\  
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/* 88DMD"$B  
**Utility.java gy5R"_MU  
*/ &Z7NF|  
package NetFox; !Bhs8eGr3  
bp P3#~ K  
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public class Utility { 9t&m\J >8;  
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public Utility() -&np/tEu&  
{ (.g?|c  
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} h)X"<a++N  
X`k#/~+0  
//线程睡眠 OkQtM nq  
public static void sleep(int nSecond) oUN;u*  
{ 1@^*tffL:  
try{ a0&R! E;  
Thread.sleep(nSecond); b5^-qc6X  
} ;k,#o!>  
catch(Exception e) IvB)d}p  
{ 
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e.printStackTrace (); A_|X54}w&  
} Twk,R. O  
} \U HI%1^  
xG,L*3c{o  
//日志 OH`|aqN  
public static void log(String sMsg) zj#8@gbh+  
{ c7 O$< F  
System.err.println(sMsg); U#(#U0s*-  
} %I%OHs  
\7*"M y*  
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public static void log(int sMsg) B>e},!  
{ ?
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System.err.println(sMsg); '2S?4Z  
} >s>{+6e  
} Uc]sWcR  
`& ]H`KNa  
OUtMel_
 
/* <;zcz[~  
**TestMethod.java Uk0 0lPG.U  
*/ %j;mDR95  
package NetFox; K,f- w2!  
VNxhv!w  
Y i`wj^  
public class TestMethod { aHSl_[  
*nV*WUS3  
$ I|K<slV  
public TestMethod() d
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{ ///xx/weblogic60b2_win.exe T1YbF/M'  
try{ 7\EY&KI"0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^eCMATE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?0'db  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )L$)qfQ~x  
fileFetch.start(); >~rytg]f  
} A=\:b^\  
catch(Exception e){e.printStackTrace ();} CdTE~O<)  
&u9@FFBT8  
n]v,cfn/=<  
} *ZV=4[#bT  
+o}mV.&1,  
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public static void main(String[] args) =g$>]AE  
{ }/.GB5Ej  
new TestMethod(); [>LL  
} sx@%3j  
} }\hz@G<  
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