http断点续传简单实现（java)

/* 7NQEnAl  
**SiteFileFetch.java 9<1dps=c  
*/ !,JV<(7k  
package NetFox; HV8=b"D"  
import java.io.*; AP/#?   
import java.net.*; PI$K+}E  
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public class SiteFileFetch extends Thread { 8QFg6#"O  
:#Nrypsu  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %"BJW  
long[] nStartPos; //开始位置 QJtO~~-  
long[] nEndPos; //结束位置 'Em633  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =r>u'wRQ  
long nFileLength; //文件长度 D[p`1$E-1v  
boolean bFirst = true; //是否第一次取文件 Isg\ fSK<j  
boolean bStop = false; //停止标志  ]YKxJ''u  
File tmpFile; //文件下载的临时信息 FZ=xy[q]~  
DataOutputStream output; //输出到文件的输出流 `E8D5'tt  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #9p|aS\  
public SiteFileFetch(SiteInfoBean bean) throws IOException `]wk)50BVp  
{ b_a6|  
siteInfoBean = bean; F%G} >xn  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^.@F1k  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); kJ.0|l0  
if(tmpFile.exists ()) ?dAy_| zD  
{ EEj.Kch}4  
bFirst = false; sc$I,|d2  
read_nPos(); )H[Pz.'ah0  
} ?CE&F<?#@  
else *apkw5B}C  
{ CK(`]-q>,  
nStartPos = new long[bean.getNSplitter()]; U,7}VdO  
nEndPos = new long[bean.getNSplitter()]; jUd)|v+t  
} QEc4l[^{.B  
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} n|eM}ymF+  
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public void run() V3q[$~9  
{ tYMPqP,1.  
//获得文件长度 1}3tpO;  
//分割文件 `{9bf)vP6  
//实例FileSplitterFetch gvoYyO#cm  
//启动FileSplitterFetch线程 `zsooA Gt  
//等待子线程返回 eR:C?v  
try{ sI6coe5n  
if(bFirst) y1 a1UiHGP  
{ YpEH(tq  
nFileLength = getFileSize(); ##a.=gl  
if(nFileLength == -1) 1;eWnb(  
{ J(w 3A)(  
System.err.println("File Length is not known!"); :r9<wbr)k0  
} V{n7KhN~Y!  
else if(nFileLength == -2) D4$2'h  
{ /o9 0O&  
System.err.println("File is not access!"); [Z;ei1l  
} O9_SVX
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else #O^%u,mJj  
{ t:*1*;  
for(int i=0;i<nStartPos.length;i++) L"}tJM.d  
{ H7(D8.y )  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .:~E.b  
} z"f+;1  
for(int i=0;i<nEndPos.length-1;i++) [I`:%y  
{ -9(pOwN |m  
nEndPos = nStartPos[i+1]; kbZp
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} ]Wtg.y6;  
nEndPos[nEndPos.length-1] = nFileLength; I %|;M%B  
} lE
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} ^o4](l  
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3? F~H  
//启动子线程 u9N/9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }!V-FAL  
for(int i=0;i<nStartPos.length;i++) UHR%0ae  
{ kO4'|<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y-lTPR<Eq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G%viWWTY  
nStartPos,nEndPos,i); (@V_47o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b*1yvkX5  
fileSplitterFetch.start(); UT0}Ce>e  
} GI6]Ecc  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ako]34Rl,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); IYv.~IQO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", CV)K=Br5&_  
nEndPos = " + nFileLength); a9NIK/9  
// fileSplitterFetch[nPos.length-1].start(); "EwzuM8f  
8J:=@X^}  
% _nmv  
//等待子线程结束 D~n-;T  
//int count = 0; d .%2QkL  
//是否结束while循环 Yz#E0aTTA  
boolean breakWhile = false; _ Y7Um  
'3?-o|v@D  
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while(!bStop) wV-9T*QrM  
{ <!F".9c@A  
write_nPos(); #n]K$k>  
Utility.sleep(500); oxL)Jx\c9A  
breakWhile = true; TjHt:%7.  
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for(int i=0;i<nStartPos.length;i++) 6q^\pJY%&7  
{ -kHJH><j  
if(!fileSplitterFetch.bDownOver) _=}.Sg5Q  
{ xjD."q  
breakWhile = false; Q]e]\J  
break;  \>||  
} 2_}oOt?qiM  
} 3)I]bui  
if(breakWhile) @saK:z  
break; 29cx(  
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//count++; 'x5p ?m  
//if(count>4) *W;;L_V"   
// siteStop(); sf/m@425  
} TbLU[(m-n  
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System.err.println("文件下载结束！"); <KfR)7I$0a  
} L/In~'*-  
catch(Exception e){e.printStackTrace ();} W]XM<# ^^  
} 2_ 1RJ
 
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//获得文件长度 q"EW*k+ )  
public long getFileSize() e N v\ZR1  
{ n.t5:SW  
int nFileLength = -1; ;M~9Yr=1  
try{ Y>atJ  
URL url = new URL(siteInfoBean.getSSiteURL()); TO.STK`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6lT< lzT  
httpConnection.setRequestProperty("User-Agent","NetFox"); maeQ'Sv_&  
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 A@9\Qd  
int responseCode=httpConnection.getResponseCode(); c91^7@Xv  
if(responseCode>=400) :,fT^izew  
{ Zu2`IzrG#  
processErrorCode(responseCode); JY@bD:  
return -2; //-2 represent access is error MV2$
0  
} \Zh&[D!2  
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iJj!-a:z.  
String sHeader; R!yh0y}Z  
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for(int i=1;;i++) Pm%5c\ef  
{ P(DEf(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ![$`Ivro`  
//Utility.log(in.readLine()); [+QyKyhTO  
sHeader=httpConnection.getHeaderFieldKey(i); QO0@Ax\b  
if(sHeader!=null) <-fvYer  
{ BMI`YGjY1  
if(sHeader.equals("Content-Length")) Ghc U~  
{ %?, 7!|Ls  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ZjY,k  
break; ^$}O?y7O  
} -2!S>P Zs  
} :J_UXtx  
else VrLp5?Bh  
break; zA}JVB  
} Z6rZAwy  
} 1zC
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catch(IOException e){e.printStackTrace ();} Wp+lI1t  
catch(Exception e){e.printStackTrace ();} I?E+  
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Utility.log(nFileLength); x2a ?ugQ  
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return nFileLength; $_;rqTk]g  
} qA\&%n^j]  
+nHr+7}  
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//保存下载信息（文件指针位置） ah f,- ?S  
private void write_nPos() kZo#Ny  
{ xQU//kNL  
try{ H }]Zp  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H C,5j)1  
output.writeInt(nStartPos.length); d}tmZ*q  
for(int i=0;i<nStartPos.length;i++) 4n@>gW  
{ bCr W'}:de  
// output.writeLong(nPos); )P?Fni}  
output.writeLong(fileSplitterFetch.nStartPos); QV.>Cy  
output.writeLong(fileSplitterFetch.nEndPos); %rJDpB{  
} <bo^uw  
output.close(); n#Dy YVb  
} J[r_ag  
catch(IOException e){e.printStackTrace ();} l)o!&]2  
catch(Exception e){e.printStackTrace ();} (gPB@hAv  
} B~k{f}  
'3U,UD5EG  
)B+o F7  
//读取保存的下载信息（文件指针位置） $GU s\  
private void read_nPos() ("PZ!z1m1  
{ 9M'"q7Kh  
try{ 1Az&BZU[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qTRP2rH,L&  
int nCount = input.readInt(); h.]^o*DJ  
nStartPos = new long[nCount]; SmD#hE[  
nEndPos = new long[nCount]; u{&=$[;  
for(int i=0;i<nStartPos.length;i++) 7P}l^WX  
{ }~=<7|N.  
nStartPos = input.readLong(); @%2crJnkS  
nEndPos = input.readLong(); F):kF_ho  
} @BjB Mi,  
input.close(); WRkuP
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} W( sit;O  
catch(IOException e){e.printStackTrace ();} BeQ'\#q,  
catch(Exception e){e.printStackTrace ();} Ix,b-C~  
} N0}[&rE 8  
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private void processErrorCode(int nErrorCode) f/Y7@y  
{ t
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System.err.println("Error Code : " + nErrorCode); `>g\gaQ  
} 3BGcDyYE  
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//停止文件下载 M,p0wsj;  
public void siteStop() E#Ue9J  
{ 1|-C(UW>  
bStop = true; fKFD>u0%  
for(int i=0;i<nStartPos.length;i++) 17c`c.yP  
fileSplitterFetch.splitterStop(); 0YL*)=pD,  
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} .@+M6K*  
} z1,#ma}.  
//负责部分文件的抓取 m(:R(K(je  
**FileSplitterFetch.java S1)g\Lv  
*/ ~N| aCi-X  
package NetFox; bA Yp }  
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import java.io.*; |x1Ttr,  
import java.net.*; R+He6c!?9  
5xnEkg4q4  
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public class FileSplitterFetch extends Thread { > 2/j  
@XL49D12c  
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String sURL; //File URL *L>usLh  
long nStartPos; //File Snippet Start Position z;@<
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long nEndPos; //File Snippet End Position s0vcGh
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int nThreadID; //Thread's ID ] s 2ec  
boolean bDownOver = false; //Downing is over QD^=;!  
boolean bStop = false; //Stop identical
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FileAccessI fileAccessI = null; //File Access interface g0a!auWM  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException NcwUK\  
{ "30=!k  
this.sURL = sURL; [:e>FXV  
this.nStartPos = nStart; !@Vj&>mH$  
this.nEndPos = nEnd; `WC4:8  
nThreadID = id; S\sy^Kt~4:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 y|*4XF<b  
} H3d|eO4+W  
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public void run() <?8cVLW}O  
{ d/3&3>/  
while(nStartPos < nEndPos && !bStop) wod{C!  
{ ~ W8 M3(^  
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v[x 5@$  
try{ #3?"#),q
 
URL url = new URL(sURL); cw~GH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l,A\]QDvl  
httpConnection.setRequestProperty("User-Agent","NetFox"); e*( _Cvxp  
String sProperty = "bytes="+nStartPos+"-"; =8p[ (<F=  
httpConnection.setRequestProperty("RANGE",sProperty); "Ya;
&F.'  
Utility.log(sProperty); rc%*g3ryLG  
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InputStream input = httpConnection.getInputStream(); uF|[MWcy0#  
//logResponseHead(httpConnection); +U<Ae^V
 
l{ fL
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byte[] b = new byte[1024]; sZqi)lo-s  
int nRead; >2mY%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) aOoWB^;6  
{ 6
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nStartPos += fileAccessI.write(b,0,nRead); cY~lDLyB  
//if(nThreadID == 1) uSCI  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r[j@@[)"  
}
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Utility.log("Thread " + nThreadID + " is over!"); G
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bDownOver = true; p<@+0Uw2  
//nPos = fileAccessI.write (b,0,nRead); GBd mT-7  
} &w%%^ +n |  
catch(Exception e){e.printStackTrace ();} a,M/i&.e`  
} )In;nc  
} G jrN1+9=  
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//打印回应的头信息 e
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public void logResponseHead(HttpURLConnection con) kwt;pxp i  
{ ?0s&Kz4B  
for(int i=1;;i++) SnO,-Rg  
{ Qej<(:J5  
String header=con.getHeaderFieldKey(i); uA%F0oM  
if(header!=null) Gn10)Uf8X  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); A#79$[>w  
Utility.log(header+" : "+con.getHeaderField(header)); SS,'mv  
else aMJ9U)wnK  
break; @(tuE  
} <("P5@cExU  
} 3URrK[%x`  
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public void splitterStop() ,}Ic($To  
{ AlgVsE%Va  
bStop = true; VD=F{|^  
} Y:'c<k  
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u
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} P(z
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/* _NbhWv  
**FileAccess.java V3\}]5  
*//文件访问(定位，写) FC8= ru  
package NetFox; A)^A2xZQ  
import java.io.*; ?[O Sy.6  
l{\@+m  
n] n3/wpO  
public class FileAccessI implements Serializable{ Yg`z4U'6~  
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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 UDa\*  
RandomAccessFile oSavedFile; @L^30>?l  
long nPos; 'cbD;+YH  
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;|K(6)  
public FileAccessI() throws IOException W}oAgUd  
{ ';x5 $5k'  
this("",0); zB{be_Tw  
} \6Hu&WHy  
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public FileAccessI(String sName,long nPos) throws IOException TqMy">>  
{ /E
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oSavedFile = new RandomAccessFile(sName,"rw"); )'?@raB!  
this.nPos = nPos; gMZ?MG  
oSavedFile.seek(nPos); j,JGs[A  
} V|dKKb[Lve  
5 %aT  
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public synchronized int write(byte[] b,int nStart,int nLen) o//PlG~  
{ T k>N4yq  
int n = -1; $yg}HS7HC  
try{ !7[Rhk7bW  
oSavedFile.write(b,nStart,nLen); dCMWv~>  
n = nLen; l.i&.;f  
} C{):jH,Rf  
catch(IOException e) y#;@~S1W  
{ V?Zvu9b&  
e.printStackTrace (); Eq/%k $6#1  
} "Mmvf'N  
/!0{9F<  
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return n; :j,e0#+sA  
} |"a%S,
I'  
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}  kQm\;[R  
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/* x:Kca3pv_  
**SiteInfoBean.java enT.9|vm/  
*/ "ealYve
u  
package NetFox; P/FO,S-V  
#fYz367>  
bKH8/*Yk  
public class SiteInfoBean { /CN^">|_  
nPUq+cXy]C  
';!02=-@  
private String sSiteURL; //Site's URL t1 .6+  
private String sFilePath; //Saved File's Path E8Wgm 8  
private String sFileName; //Saved File's Name )f0t"l
k  
private int nSplitter; //Count of Splited Downloading File !Hr +|HKQ?  
v 1O*
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public SiteInfoBean() 2}Q)&;u  
{//nSplitter的缺省值为5 cS ;hyLd  
//default value of nSplitter is 5 9Kyr/6w4-k  
this("","","",5); Re b^w,  
} k^.9;FmQ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g=:C/>g  
{ `7|v  
sSiteURL= sURL; N|h}'p  
sFilePath = sPath; =`
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sFileName = sName; 3u8HF-  
this.nSplitter = nSpiltter; L+s,,k  
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/5_!Y>W  
} p_QL{gn  
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public String getSSiteURL() eW+z@\d9Gz  
{ ZuF-$]oL&  
return sSiteURL; YXa^jFp  
} gKS0!U  
lG;sDR|)(  
nMXSpX>!|  
public void setSSiteURL(String value) [ua{qJ9  
{ ]pr;ME<M{  
sSiteURL = value; j4Cad  
} |k+Y >I&  
y4Plm.  
69,;=  
public String getSFilePath() @K]D :MSS  
{ r!etj3  
return sFilePath; 9[B*CD|  
} V5RfxWtm:  
1NT@}j~/  
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public void setSFilePath(String value) 5o2;26c  
{ f|_iHY  
sFilePath = value; t*^Q`V wQ  
} +B
%ZB9  
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public String getSFileName() 3m?3I2k  
{ t8 #&bUX  
return sFileName; X'WbS  
} 'zZN]P  
q!9SANTx  
Ry0n_J:7  
public void setSFileName(String value) zrG&p Z  
{ Qg9 N?e{z  
sFileName = value; 2bfKD'!aH  
} 4?,N;Q  
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public int getNSplitter() 3
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{ L*1C2EL/q  
return nSplitter; `(EY/EsY  
} =\?KC)F*e  
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public void setNSplitter(int nCount) PygaW&9Z|d  
{ Lu6!W  
nSplitter = nCount; 5R/!e`(m  
} ,Rk
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} ">lu8F  
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/* Qhsh{muw(  
**Utility.java Y:oL  
*/ CbA!  
package NetFox; :}v&TQ  
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public class Utility { kc\^xq~  
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public Utility() \SS1-UbL  
{ <|~X,g;f  
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} q<yp6Q3^  
8/x@
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//线程睡眠 #7+oM8b  
public static void sleep(int nSecond) 34Q l7LQp[  
{ KQj5o>} 6  
try{ fn(KmuNA  
Thread.sleep(nSecond); |[;9$V
n  
} +HQX]t:Y  
catch(Exception e) lO9ML-8C1  
{ 5\V>Sj(  
e.printStackTrace (); f+j\,LJ  
} &aqF||v%)  
} K 38e,O  
)'KkO$^&  
//日志 \m~?mg"#  
public static void log(String sMsg) 61HU_!A8S  
{ r1yz ?Y_P  
System.err.println(sMsg); M3c-/7
 
} h.E8G^}@  
;z/Z(7<;;  
;tP-#Xf  
public static void log(int sMsg) $+!/=8R)  
{ SZW`|ajH  
System.err.println(sMsg); B>WAlmPA  
} +1~Y2   
} z;JyHC)  
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'.r_6X$7Jt  
/* <spVUp  
**TestMethod.java A'HFpsa  
*/ L}pMjyM  
package NetFox; K>hQl
s+  
`h}fS4CO  
9q5jqFQ  
public class TestMethod { X]d;x/2  
A}v!vVg  
*]NG@^y  
public TestMethod() )-%3;e<w  
{ ///xx/weblogic60b2_win.exe 9&}$C]`  
try{ U,Ya^2h%  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); HjAhz  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4t]ccqX*{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); GKTt!MK  
fileFetch.start(); 7v3'JG1r-  
} 1t wC-rC  
catch(Exception e){e.printStackTrace ();} Jd?N5.  
kVR_?ch{  
`>-fU<Q1  
} ]-h;gN

  
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public static void main(String[] args) mQdF+b1o  
{ \9j +ejGf  
new TestMethod(); (Ild>_Tdb`  
} Vea2 oQq  
} 5]pvHc  
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