http断点续传简单实现（java)

/* YFVNkBO%  
**SiteFileFetch.java ^qaS  
*/ V^P]QQ\ )  
package NetFox;
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import java.io.*;  GIt~"X  
import java.net.*; v:Av2y  
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public class SiteFileFetch extends Thread { f;C*J1y  
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SiteInfoBean siteInfoBean = null; //文件信息Bean =7JvS~s  
long[] nStartPos; //开始位置 s0 ZF+6f  
long[] nEndPos; //结束位置 J2$L[d^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3TRzDE(J  
long nFileLength; //文件长度 zqDIwfW  
boolean bFirst = true; //是否第一次取文件 gNdEPaaFI  
boolean bStop = false; //停止标志 )x/Spb  
File tmpFile; //文件下载的临时信息 UJXRL   
DataOutputStream output; //输出到文件的输出流 p9;Oe,Il  
=rA"|=  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G6C#
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public SiteFileFetch(SiteInfoBean bean) throws IOException @O/Jy2>3H  
{ 5U&b")3IT!  
siteInfoBean = bean; oh k.;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !1tHg Z2\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); kCXQHX  
if(tmpFile.exists ())  :1q)l  
{ v`"z  
bFirst = false; &@O]'  
read_nPos(); [X'XxYbZ  
} /Q4TQ\:  
else |F }y6 gH  
{ U{vt9t  
nStartPos = new long[bean.getNSplitter()]; g]IRv(gDh  
nEndPos = new long[bean.getNSplitter()]; la7VeFT  
} }Fd4; ]  
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} 9E/{HNkf  
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public void run() $4^cbk  
{ =IQ+9Fl2  
//获得文件长度 q6h'=By  
//分割文件 "@1e0`n Q  
//实例FileSplitterFetch P|> fO'  
//启动FileSplitterFetch线程 Yv?nw-HM  
//等待子线程返回 sb Wn1 T U  
try{ 9`P<|(  
if(bFirst) Gkz\By  
{ >h^CC*&'pw  
nFileLength = getFileSize(); WaY_{
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if(nFileLength == -1) yrp5\k*{y  
{ hk =nXv2M  
System.err.println("File Length is not known!"); D#ZzhHHP  
} {:U zW\5l)  
else if(nFileLength == -2) O)y|G%O  
{ J<g$hk  
System.err.println("File is not access!"); .+|HJ(  
} qPEtMvL #  
else >K }j}M%  
{ \qx$h!<  
for(int i=0;i<nStartPos.length;i++) kvWP[! j?)  
{ D=hy[sDBw  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Y$3 &?LA  
} r5U[jwP  
for(int i=0;i<nEndPos.length-1;i++) .<0|V  
{ |'$E-[  
nEndPos = nStartPos[i+1]; Tm!pAD  
} J!O{.
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nEndPos[nEndPos.length-1] = nFileLength; ]ow$VF{y  
} dNH6%1(s]0  
} [D!-~]5  
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Gk<M@d^hQ  
//启动子线程 h^yLmRL  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;VhilWaF-  
for(int i=0;i<nStartPos.length;i++) Rra3)i`
*  
{ %49P<vo`?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %w+"MkH _  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c/:d$o-  
nStartPos,nEndPos,i); !GB\-(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); > -P UY  
fileSplitterFetch.start(); asDk@Gcu  
} ;WydXQ}Q^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eIZ7uSl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yQAW\0`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p:*)rE  
nEndPos = " + nFileLength); v:2*<;  
// fileSplitterFetch[nPos.length-1].start(); DhN{Y8'~  
 F#0y0|  
m2%OX"#e  
//等待子线程结束 B|\pzWD%  
//int count = 0;  rG#o*oA  
//是否结束while循环 )uj:k*`)  
boolean breakWhile = false; 7Cx*Ts$  
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while(!bStop) \<cs:C\h7  
{ v[k;R  
write_nPos(); .[%
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Utility.sleep(500); UH8q:jOi  
breakWhile = true; Y[_{tS#u  
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for(int i=0;i<nStartPos.length;i++) DC9\Sp?  
{ +<l6!r2Z  
if(!fileSplitterFetch.bDownOver) 6wIo95`  
{ ]2:w?+
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breakWhile = false; P
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break;
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} 54X=58Q  
} '?j[hhfB-  
if(breakWhile) ;kW+  
break; F0.Rv):  
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UY(pKe>  
//count++; 3pzp6o2  
//if(count>4) ^{<!pvT  
// siteStop(); BM~>=emc  
} Sw1z^`  
Eo\pNz#)  
)$EmKOTt:  
System.err.println("文件下载结束！"); pr;n~E 'kq  
} fGZZ['E  
catch(Exception e){e.printStackTrace ();} m`;dFL7"E  
} (]_smsok  
^bD)Tg5K  
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//获得文件长度 DGc5Lol~  
public long getFileSize() 9Dat oi  
{ !^[i"F:G  
int nFileLength = -1; AVn?86ri  
try{ 0mt lM(  
URL url = new URL(siteInfoBean.getSSiteURL()); UFE# J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wBuos}/  
httpConnection.setRequestProperty("User-Agent","NetFox"); u&M:w5EM  
+'-i(]@!'  
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int responseCode=httpConnection.getResponseCode(); hFW{qWP  
if(responseCode>=400) J!\Cs1!f  
{ ]'.D@vFGO  
processErrorCode(responseCode); f9%M:cl  
return -2; //-2 represent access is error !t;B.[U *  
} #<$pl]>}t  
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*#n#J[  
String sHeader; Z2t'?N|_  
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for(int i=1;;i++) qsA`\%]H  
{ u5'jIq
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ' ?4\  
//Utility.log(in.readLine()); dmB _`R  
sHeader=httpConnection.getHeaderFieldKey(i); w\K(kNd(  
if(sHeader!=null) Wr j<}L|  
{ 5bj9S  
if(sHeader.equals("Content-Length"))
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{ )yl
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ln1QY"g  
break; M?g
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} Hf$pwfGcY]  
} 3D}rxI8N  
else Ii.?| u  
break; B[$L)y'-;  
} uo TTHj7cq  
} y/.I<5+Bu  
catch(IOException e){e.printStackTrace ();} M#u~]?hS  
catch(Exception e){e.printStackTrace ();} 0Tv0:c>8;(  
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Utility.log(nFileLength); 'kBq@>  
dzbFUDJ  
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return nFileLength; #5%\~f  
} FJ+n- \  
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2(i@\dZCb<  
//保存下载信息（文件指针位置） h,fC-+H5  
private void write_nPos() (teK0s;t5k  
{ eZ G#op  
try{ [uLpm*7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i)1013b  
output.writeInt(nStartPos.length); #xoFcjRE  
for(int i=0;i<nStartPos.length;i++) gebDNl\Y2  
{ EyDH-}Y  
// output.writeLong(nPos); k .#I
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output.writeLong(fileSplitterFetch.nStartPos); j /)A<j$  
output.writeLong(fileSplitterFetch.nEndPos); oc>N| ww:  
} FoW|BGA~  
output.close(); xbNL <3"a  
} "*T4%3dA  
catch(IOException e){e.printStackTrace ();} C}=9m A  
catch(Exception e){e.printStackTrace ();} +HSKFp  
} 
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-)%gMD~z1  
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//读取保存的下载信息（文件指针位置） WNK)IC~c  
private void read_nPos() th^&wp  
{ dcH@$D@~S  
try{ PNB E  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); gWGh:.
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int nCount = input.readInt(); W @]t  
nStartPos = new long[nCount]; jr2wK?LbB  
nEndPos = new long[nCount]; (`js/7[`H[  
for(int i=0;i<nStartPos.length;i++) hQ80R B  
{ ^//`Dz  
nStartPos = input.readLong(); ec&K}+p@  
nEndPos = input.readLong(); l Zz%W8"  
} 0..]c-V(G  
input.close(); Q35D7wo'}  
} IIY3/  
catch(IOException e){e.printStackTrace ();} |@Ze{\  
catch(Exception e){e.printStackTrace ();} 18WJ*q7:  
} ] L6LB\  
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private void processErrorCode(int nErrorCode) 9#:B_?e=  
{ 5_+pgJL  
System.err.println("Error Code : " + nErrorCode); L(q~
%  
} Ve[[J"ze  
m:)sUC0  
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//停止文件下载 9CFh'>}$  
public void siteStop() :;URLl0  
{ Zv5vYe9Ow  
bStop = true; XR+  
for(int i=0;i<nStartPos.length;i++) {lbNYjknS  
fileSplitterFetch.splitterStop(); l&_PsnU  
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} ]-{A"tJ  
} m9mkZ:r(kV  
//负责部分文件的抓取 4XgzNwm  
**FileSplitterFetch.java f/vsf&^O  
*/ .c]@xoC  
package NetFox; I\<)9`O  
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import java.io.*; i'3)5  
import java.net.*; b6d}<b9#  
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public class FileSplitterFetch extends Thread { S#b)RpY  
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String sURL; //File URL 4O7 {a  
long nStartPos; //File Snippet Start Position YM&i  
long nEndPos; //File Snippet End Position rCd*'Qg  
int nThreadID; //Thread's ID f>[{1M]n\  
boolean bDownOver = false; //Downing is over qkA8q@Y4|  
boolean bStop = false; //Stop identical Gx;-1  
FileAccessI fileAccessI = null; //File Access interface [mFgo il  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v<vaPvW  
{ !,OY{='  
this.sURL = sURL; Sr>5V  
this.nStartPos = nStart; U"535<mR  
this.nEndPos = nEnd; ]92=PA>75  
nThreadID = id; m1DrT>oN'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 i?D)XXB85  
} |w.h97fj  
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public void run() oC}2 Z{  
{ w"q^8"j!  
while(nStartPos < nEndPos && !bStop) :_:o%  
{ 3/Dis) v8  
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try{ o('6,D  
URL url = new URL(sURL); df{6!}/(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AWDy_11Nm  
httpConnection.setRequestProperty("User-Agent","NetFox");  @7J;}9E  
String sProperty = "bytes="+nStartPos+"-"; yL_\&v  
httpConnection.setRequestProperty("RANGE",sProperty); "4L_BJZ  
Utility.log(sProperty); y3ST0=>j}  
{
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InputStream input = httpConnection.getInputStream(); .>NPgdI  
//logResponseHead(httpConnection); {yM@3v~  
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byte[] b = new byte[1024]; {Z}zT1kA  
int nRead; < 49\B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) M%2w[<-8c  
{ co*XW  
nStartPos += fileAccessI.write(b,0,nRead); j/uzsu+  
//if(nThreadID == 1) a*qc
  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 87rHW@\](  
} |XJ|vQGU  
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Utility.log("Thread " + nThreadID + " is over!"); (^$SMuC
 
bDownOver = true; LZ8xh  
//nPos = fileAccessI.write (b,0,nRead); YJ>P+e\o9  
} yJ?=HH?  
catch(Exception e){e.printStackTrace ();} 8u"HW~~=  
} OBf$0  
} S$qpClXS,  
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!H(V%B
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//打印回应的头信息 F6Qnz8|  
public void logResponseHead(HttpURLConnection con) :Fi$-g  
{ %t%D|cf  
for(int i=1;;i++) `.F3&pA  
{ Muok">#3.  
String header=con.getHeaderFieldKey(i); [fg-"-+:M  
if(header!=null) T^S$|d  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -*;JUSGh  
Utility.log(header+" : "+con.getHeaderField(header)); 5}:`CC2,S~  
else Jp(CBCG{F  
break; MS& 'Nj  
} Asli<L(?`  
} }^azj>p5  
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public void splitterStop() ~T9wx  
{ 4S*dNYc  
bStop = true; R0T{9,;[`  
} fz<GPw  
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} $ZRvvm!f  
iu QMVtv  
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/* b5W(}ka+  
**FileAccess.java qsdgG1<  
*//文件访问(定位，写) Y``]66\Fp  
package NetFox; BO'7c1FU  
import java.io.*; 4E@_Fn_#  
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public class FileAccessI implements Serializable{ O|*-J  
t>eeOWk3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 WU~L#Ih.V  
RandomAccessFile oSavedFile; uYXkD#{  
long nPos; yE|hA2G?0  
EU.!/'<  
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public FileAccessI() throws IOException qb+Gjgp  
{ g])iU9)8  
this("",0); ,OBJ>_5  
} jAfqC@e  
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public FileAccessI(String sName,long nPos) throws IOException z,(.` %h  
{ n"f:6|<  
oSavedFile = new RandomAccessFile(sName,"rw"); j>#ywh*A  
this.nPos = nPos; 6!v$"u|[!'  
oSavedFile.seek(nPos); vAfYONU  
} nTr{D&JS  
;8yEhar  
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public synchronized int write(byte[] b,int nStart,int nLen) 'EG/)0t`  
{ #1Iev7w  
int n = -1; cN~F32<  
try{ FLLfTkXdI  
oSavedFile.write(b,nStart,nLen); 15M!erT  
n = nLen; b ; U  
} +Os9}uKf  
catch(IOException e) t<MO~_`!  
{ bCV_jR+  
e.printStackTrace (); bOD]`*q  
} hZ-?-F?*@  
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~$m:j];  
return n; l{hO"fzy  
} ISg-?h/  
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}
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/* d?)Ic1][  
**SiteInfoBean.java ;!)gjiapw  
*/ G|qsJ  
package NetFox; BB.120v&N  
'k/:3?R  
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public class SiteInfoBean { $.3J1DU  
x57O.WdN  
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private String sSiteURL; //Site's URL /hAy1V6  
private String sFilePath; //Saved File's Path 3 V$ \s8  
private String sFileName; //Saved File's Name ,e;_ Vb  
private int nSplitter; //Count of Splited Downloading File DtkOb,wY  
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lA n^)EL  
public SiteInfoBean() 7towjwr  
{//nSplitter的缺省值为5 vCn\_Nu;W&  
//default value of nSplitter is 5 ~=?^v[T1  
this("","","",5); dY`P  
} JN3&(t  
#Ht;5p>5  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {~ 1 ~V  
{ 5W(`lgVs,  
sSiteURL= sURL; &<t`EI];)4  
sFilePath = sPath; E6#")2C~  
sFileName = sName; lfqsoIn;  
this.nSplitter = nSpiltter; /~pB_l  
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9b)'vr*Hy7  
} fk\hrVP
 
 jRhRw;  
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public String getSSiteURL() rAS2qt  
{ Vn?|\3KY  
return sSiteURL; 69N8COLB  
} >Y;[+#
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B !Z~jT  
public void setSSiteURL(String value) Pa"[&{:  
{ -gpHg  
sSiteURL = value; '25zb+-  
} <=@6UPsn2  
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QsyM[;\j:  
public String getSFilePath() m.c2y6<=  
{ X)S4vqf}  
return sFilePath; Kc+TcC  
} :a_MT  
C^*}*hYk$  
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public void setSFilePath(String value) @-.Tgpe@a  
{ ;R^=($X  
sFilePath = value; _g6H&no[  
} k]S`A,~  
;TboS-Y  
56H~MnX  
public String getSFileName() oWBjPsQ  
{ 0r]-Ltvl?}  
return sFileName; 0[ZwtfL1  
} U\dLq&=V  
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public void setSFileName(String value) Wo6C0Z3g}  
{ I|_U|H!`  
sFileName = value; h&z(;B!;y.  
} &"clBRVg  
j4$NQ]e^4  
-P28pVX`  
public int getNSplitter() A#nSK#wS61  
{ N
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return nSplitter; nBzju?X)I  
} ]wEFm;N  
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public void setNSplitter(int nCount) ogG:Ai)90  
{ 4\m#:fj %  
nSplitter = nCount; bP7_QYQ6  
} " l>tFa  
} |]]Rp  
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/* Q
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**Utility.java bH.f4-.u>)  
*/ fn Pej?f:  
package NetFox; 5wbR}`8  
i?6#>;f  
#fq&yjl#A  
public class Utility { 6d;RtCENo  
'@WS7`@-y  
Je=k.pO1  
public Utility() _p0G8  
{ 3mT6HGSKR  
1=mb2A  
p s_o:*$l  
} BP8jReX^  
`$ZBIe/u  
//线程睡眠 ~!"z`&
  
public static void sleep(int nSecond) #%.fsJNA$  
{ q!<n\X3]u  
try{ jKp79].  
Thread.sleep(nSecond); :nxBM#:xu  
} hf5+$^RZ  
catch(Exception e) sg4TX?I   
{ "2hs=^&8  
e.printStackTrace (); 0134mw%jk  
} &@z M<A  
} 7rIEpN>*  
#F ;@Qi3z  
//日志 j:[#eC  
public static void log(String sMsg) AV;x'H7G  
{ NH!x6p]n  
System.err.println(sMsg); K#[z5  
} uw{K&Hxw  
B=|m._OL]n  
0w?G&jjNtM  
public static void log(int sMsg) kNv/L$oG  
{ zUz j F  
System.err.println(sMsg); h8:5[;e  
} *q0vp^?  
} T49^  
5`{u! QE  
C |P(,Xp  
/* \'>d.'d  
**TestMethod.java 7-4S'rq+  
*/ ^) 5*?8#  
package NetFox; dd!Q[]$ }  
C$^WW}S  
AO]1`b:  
public class TestMethod { KWH:tFL.  
8P*wt'Q$  
TH? wXd\  
public TestMethod() `tJ"wpCf6  
{ ///xx/weblogic60b2_win.exe Wrs6t  
try{ ;I]$N]8YI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); o*:D/"gb  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); b$=c(@]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -
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}u>  
fileFetch.start(); !">EZX  
} j&Y{ CFuZ  
catch(Exception e){e.printStackTrace ();} )q>q
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Q =4~uz|  
} -5MQ/ujQ  
D[<~^R;*  
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public static void main(String[] args) Sj
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{
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new TestMethod(); S=g E'"LT  
} 5@`dKFB5  
} $Sc;
  
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