http断点续传简单实现（java)

/* k_D4'(V:b  
**SiteFileFetch.java )-+\M_JK5  
*/ ?$|uT  
package NetFox; W\@?e32  
import java.io.*; 9Z,*h-o  
import java.net.*; {W5ydHXy  
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AT B\^;n.  
public class SiteFileFetch extends Thread { Hp)X^O"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean pk-yj~F}  
long[] nStartPos; //开始位置 NP K#].F  
long[] nEndPos; //结束位置 V_&GYXx(J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Zm%VG(l  
long nFileLength; //文件长度 kmm  
boolean bFirst = true; //是否第一次取文件 E rop9T1  
boolean bStop = false; //停止标志 I1Hw"G"&  
File tmpFile; //文件下载的临时信息 1t/dxB;  
DataOutputStream output; //输出到文件的输出流 W@I 02n2H  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =n@F$/h  
public SiteFileFetch(SiteInfoBean bean) throws IOException aO8
ch  
{ ]y3pE}R  
siteInfoBean = bean; #TMm#?lC  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9=t#5J#O  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); N\9}\Rk@  
if(tmpFile.exists ()) 3iE
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{ ^FP} qW~;9  
bFirst = false; ZCy`2Fir  
read_nPos(); 3@^MvoC  
} tHrK~|  
else }.0Bl&\UK  
{ }J
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nStartPos = new long[bean.getNSplitter()]; ecr886  
nEndPos = new long[bean.getNSplitter()]; Ua):y) A  
} L|&'jH)  
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} SArfczoB  
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public void run() TT'Ofvdc  
{ kf<c,3A  
//获得文件长度 CY34X2F  
//分割文件 W7H&R,  
//实例FileSplitterFetch y Wpi|  
//启动FileSplitterFetch线程  )|v^9  
//等待子线程返回 4L8z>9
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try{ Aj[?aL  
if(bFirst) EE+`i%  
{ *yJ[zXXjJ  
nFileLength = getFileSize(); w{pUUo:<  
if(nFileLength == -1) Y
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{ !RS9%ES_?  
System.err.println("File Length is not known!"); l :/&E 6 9  
} #Mh{<gk%ax  
else if(nFileLength == -2) MR`:5e  
{ p8Iw!HE  
System.err.println("File is not access!");
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} ^$!987"  
else [r(Qs|  
{ eqq`TT#
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for(int i=0;i<nStartPos.length;i++) @5WgqB  
{ rz6uDJ"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $(ewk):  
} Y$g}XN*)E  
for(int i=0;i<nEndPos.length-1;i++) 9M_(He -  
{ 6R`Oh uN.>  
nEndPos = nStartPos[i+1]; h{k_6ym  
} ~4\,&HH  
nEndPos[nEndPos.length-1] = nFileLength; Z?oG*G:  
} 7{f_fkbs  
} (zG.aaz*C  
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//启动子线程 ZsZcQj6G,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -?<4Og[^  
for(int i=0;i<nStartPos.length;i++) m*Lo|F  
{ m#f{]+6U  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _tAQ=eBO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), pQMtj0(y  
nStartPos,nEndPos,i); w(j^ccPD  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Tr& }$kird  
fileSplitterFetch.start(); S_v(S^x6  
} Rrg8{DZhv  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0)|Q6*E>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e}0:"R%E  
nEndPos = " + nFileLength); xY\0zQ  
// fileSplitterFetch[nPos.length-1].start(); r[_4Lo@G  
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//等待子线程结束 Z{R[Wx  
//int count = 0; mM
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//是否结束while循环 Lq (ZcEKo  
boolean breakWhile = false; {_#yz\j  
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while(!bStop) e-5?p~>  
{ M2@b
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write_nPos(); ir16   
Utility.sleep(500); EE=
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breakWhile = true; )US:.7A[.  
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for(int i=0;i<nStartPos.length;i++) q o 1lj"P  
{ 7@}$|u:JUF  
if(!fileSplitterFetch.bDownOver) nZy X_J,Vd  
{ 9\;|x  
breakWhile = false; ?!VIS>C(  
break; LN2D  
} ?7MqeR4/E  
} BZv+H=b  
if(breakWhile) BxK^?b[E8  
break; $gpG%Qj  
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//count++; L,,*gK  
//if(count>4) <plC_{Y:wu  
// siteStop(); kcie}Be  
} Q,h7Sk*  
*Vw\'%p*  
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System.err.println("文件下载结束！"); e`>{$t  
} 9Z5D\yv?H  
catch(Exception e){e.printStackTrace ();} `qVjwJ!
+  
} E\nv~Y?SG  
 Ez~'^s@  
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//获得文件长度 VdSv  
public long getFileSize() Zk8|K'oHx  
{ `1OgYs  
int nFileLength = -1; W1B)]IHc  
try{ Wo~vhv$E  
URL url = new URL(siteInfoBean.getSSiteURL()); G`fC/Le  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >gwz,{  
httpConnection.setRequestProperty("User-Agent","NetFox"); jOpcV|2  
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int responseCode=httpConnection.getResponseCode(); Eodn/  
if(responseCode>=400) jn >d*9u  
{ XdLCbY  
processErrorCode(responseCode); [[d(jV=*  
return -2; //-2 represent access is error ofYlR
|  
} r_e
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String sHeader; ]lw|pvtd  
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for(int i=1;;i++) A1P K  
{ 'TH15r@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r78TE@d  
//Utility.log(in.readLine()); \0lnxLA  
sHeader=httpConnection.getHeaderFieldKey(i); 9% l%  
if(sHeader!=null) p~noM/*2r  
{ {-|{xBd  
if(sHeader.equals("Content-Length")) M?&h~V1OI~  
{ lrf
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?(*t@ {k  
break; +xc'1id@[  
} /%_OW@ ?  
} FnJ?C&xK  
else [,2|Flf e  
break; 2I*;A5$N1  
} D]c`B  
} N2.AKH  
catch(IOException e){e.printStackTrace ();} ^rvx!?zO  
catch(Exception e){e.printStackTrace ();} pv^O"Bs  
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Utility.log(nFileLength); `tjH<  
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return nFileLength; cZ)}LX  
} %Y!Yvw^&P(  
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)_/5*Ly@  
//保存下载信息（文件指针位置） `--TP  
private void write_nPos() H[DUZ,J  
{ Q#nOJ(KV  
try{ !"8fdSfg w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BD`2l!d  
output.writeInt(nStartPos.length); -V:"l  
for(int i=0;i<nStartPos.length;i++) =gcM%=*'  
{ i1S>yV^l  
// output.writeLong(nPos); :n /@z4#  
output.writeLong(fileSplitterFetch.nStartPos); Z*-g[8FO  
output.writeLong(fileSplitterFetch.nEndPos); B'^:'uG  
} KiJT!moB  
output.close(); * S=\
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} ;j4?>3  
catch(IOException e){e.printStackTrace ();} `'V4PUe  
catch(Exception e){e.printStackTrace ();} Ug&,Y/tFw2  
} 1KjU ] r
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//读取保存的下载信息（文件指针位置） F'hHK.tT  
private void read_nPos() @:KJYm[  
{ sJ]taY ou  
try{ E*jP87g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {J^lX/D  
int nCount = input.readInt(); ve\X3"p#  
nStartPos = new long[nCount]; H@ t'~ZO
 
nEndPos = new long[nCount]; vap,y $C  
for(int i=0;i<nStartPos.length;i++) Y-7^o@y  
{ Unsogd  
nStartPos = input.readLong(); y.[Mnj  
nEndPos = input.readLong(); b!)<-|IK  
} W^s ;Bi+Nw  
input.close(); y~75r\"R
 
} {l |E:>Q2  
catch(IOException e){e.printStackTrace ();} g&`pgmUX  
catch(Exception e){e.printStackTrace ();} K# Jk
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} P{u0ftyX}  
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private void processErrorCode(int nErrorCode) Ox@sI:CT  
{ ~q~MoN<R  
System.err.println("Error Code : " + nErrorCode); CxfRVL`7  
} U4cY_p?  
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A,`8#-AX  
//停止文件下载 NOp609\^  
public void siteStop() $#]]K  
{ b?Ki;[+O  
bStop = true; 2z|*xS'G  
for(int i=0;i<nStartPos.length;i++) z(H^..<!5  
fileSplitterFetch.splitterStop(); Yb
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} P><o,s"v  
} A*um{E+  
//负责部分文件的抓取
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**FileSplitterFetch.java Qm/u h  
*/ 4)("v-p  
package NetFox; S*n@81Z  
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import java.io.*; KhMSL  
import java.net.*; =Jym%m  
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public class FileSplitterFetch extends Thread { &0`) Q
 
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String sURL; //File URL 4vwTs*eB`  
long nStartPos; //File Snippet Start Position tuhA 9}E  
long nEndPos; //File Snippet End Position ,L`$09\  
int nThreadID; //Thread's ID V#`fs|e;y  
boolean bDownOver = false; //Downing is over qu-/"w<3$  
boolean bStop = false; //Stop identical vo#UtN:q  
FileAccessI fileAccessI = null; //File Access interface s%W<dDINl  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException P<f5*L#HD  
{ R>(@ZM&  
this.sURL = sURL; m`FNIY  
this.nStartPos = nStart; :at$HCaK  
this.nEndPos = nEnd; R<=zCE`:  
nThreadID = id; `4~H/'%QB  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 A$a1(8H  
} 4'LB7}WG  

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public void run() th&[Nt7  
{ `IY/9'vT  
while(nStartPos < nEndPos && !bStop) G3{=@Z1  
{ pe{;~-|6  
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try{ Z>^pCc\lH  
URL url = new URL(sURL); 6A=8+R'`F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4X*>H  
httpConnection.setRequestProperty("User-Agent","NetFox"); b/Xbs0q  
String sProperty = "bytes="+nStartPos+"-"; $VxA0 =ad  
httpConnection.setRequestProperty("RANGE",sProperty); \R3H+W  
Utility.log(sProperty); V@\%)J'g  
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InputStream input = httpConnection.getInputStream(); 3hK#'."`N  
//logResponseHead(httpConnection); 4sP2g&  
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byte[] b = new byte[1024]; l}lIi8  
int nRead; HX6Ma{vBk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L^{|uP15N
 
{ Al`e/a  
nStartPos += fileAccessI.write(b,0,nRead); <dvy"Dx  
//if(nThreadID == 1) ,DZX$Ug~+E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zrU{@z$l  
} yOwA8^q  
U2%.S&wS,e  
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Utility.log("Thread " + nThreadID + " is over!"); HWVtop/  
bDownOver = true; PClMQL#  
//nPos = fileAccessI.write (b,0,nRead); }YHX-e<Yx]  
} =k oSUVO0  
catch(Exception e){e.printStackTrace ();} mSo_} je(  
} m-jHze`D3  
} :Pv*,qHE  
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//打印回应的头信息 W mm4hkf  
public void logResponseHead(HttpURLConnection con) >X51$wBL  
{ T =2=k&|  
for(int i=1;;i++) xrN &N_K#  
{ chEn|>~  
String header=con.getHeaderFieldKey(i); x1BobhU~Zl  
if(header!=null) +z$pg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); i:l<C  
Utility.log(header+" : "+con.getHeaderField(header)); }>[G5[\  
else NVl [kw  
break; 36n>jS&  
} VnT>K9&3  
} ,p9i%i  
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public void splitterStop() VG>vn`x>a  
{ :(_+7N[KA  
bStop = true; 2z@\R
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} c1xrn4f@a  
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} `4 y]Z)  
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/* )H}#A#ovj7  
**FileAccess.java aSP4a+\*  
*//文件访问(定位，写) H-p
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package NetFox; S{K0.<,E  
import java.io.*; {W\T"7H  
[+Y{%U  
k;5Pom  
public class FileAccessI implements Serializable{ WX4;l(PL=  
:5yV.7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,]5Ic.};p  
RandomAccessFile oSavedFile; Urgtg37  
long nPos; 1JEnnqu  
>Ng)k]G  
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public FileAccessI() throws IOException _U{&@}3  
{ {w <+_++  
this("",0); Xq4|uuS-O  
} dXn%lJ  
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public FileAccessI(String sName,long nPos) throws IOException %5\3Aw  
{ 5yVkb*8HS  
oSavedFile = new RandomAccessFile(sName,"rw"); _P?\.W@  
this.nPos = nPos; Q7bq  
oSavedFile.seek(nPos); 7P7b8]  
} X_$a,"'~)  
u? fTL2~  
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public synchronized int write(byte[] b,int nStart,int nLen)  oK9'  
{ T5O _LCIws  
int n = -1; 6> {r6ixs1  
try{ B%\gkl  
oSavedFile.write(b,nStart,nLen); l\$+7|W  
n = nLen; /hv#CB>1x  
} N]YtLa,t  
catch(IOException e) m?[5J)eR  
{ ]+H?@*b`  
e.printStackTrace (); {0YAzZ7  
} -p-0;Hy  
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return n; T{vR,  
} 'YSuQP>  
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} <1~^C  
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/* 8Og3yFx[rt  
**SiteInfoBean.java Ps R>V)L  
*/ v@EQ^C2.&  
package NetFox; ;Pb8YvG1$  
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public class SiteInfoBean { Wf>^bFb"$  
+'03>!V  
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private String sSiteURL; //Site's URL kB\kpW  
private String sFilePath; //Saved File's Path 2>hz_o{5',  
private String sFileName; //Saved File's Name "2Op[~V  
private int nSplitter; //Count of Splited Downloading File nwM)K
 
M1u{A^d.Z  
ms~8QL  
public SiteInfoBean() SQ#7PKH  
{//nSplitter的缺省值为5 xX@FWAj  
//default value of nSplitter is 5 (a{ZJI8_  
this("","","",5); PJ 9%/Nrh  
} O]nT>;PXX  
h[=nx^  
_ 6:ww/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [!?wyv3  
{ 68x}w Ae  
sSiteURL= sURL; }e=e",
eAT  
sFilePath = sPath; *_)E6Y?9  
sFileName = sName; 6[==BbZ  
this.nSplitter = nSpiltter; <d@pmh  
LV.&>@*  
O{n<WQd{CY  
} Q\#UWsN(T/  
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public String getSSiteURL() |NEd@  
{ iVeQ]k(u  
return sSiteURL; #pu}y,QN$  
} *]{=8zc2  
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public void setSSiteURL(String value) ?'2 v.5TQt  
{ K/Jk[29"\  
sSiteURL = value; ?L
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} o>!JrH  
BE%Z\E[[m  
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public String getSFilePath() W uf/LKj  
{ Uh\]?G[G  
return sFilePath; AM?Ec1S #a  
} A\C'dZ <N  
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public void setSFilePath(String value) )G4rJ~#@  
{ :A*0]X;  
sFilePath = value; vXf:~G]  
} ,TJ/3_lH  
X X&K=<,Ja  
HPTHF  
public String getSFileName() MHNe>C-!q  
{ >D3zV.R  
return sFileName; tnL."^%A2I  
}  wQw-:f-  
:}y| 4*z  
:f]!O@.~  
public void setSFileName(String value) kdd7Xbw-  
{ V7n >,k5  
sFileName = value; neIy~H_#!  
} !?n50  
h=Oh9zsz8  

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public int getNSplitter() 3z$HKG  
{ ?KCxrzf  
return nSplitter; >&[3  
} 4UazD_`'  
!4L#$VG  
,0FwBK  
public void setNSplitter(int nCount) tNYJQ  
{ &R0OeRToUb  
nSplitter = nCount; +&?'KZ+Z_v  
} |9x%gUm  
} GA7u5D"0  
w
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CR.bMF}  
/* bt0djJRw  
**Utility.java 3^'#
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*/ | [p68v>  
package NetFox; %OuX`w=  
5UPPk$8`  
w
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public class Utility { M,ppCHy/$  
7<fL[2-  
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public Utility() |}%(6<  
{ '+tKvTU;  
l#p}
{  
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} ~@[(U!G  
SHytyd  
//线程睡眠 lGl[^ 0  
public static void sleep(int nSecond) (y%%6#bd  
{ _r~!O$2  
try{ 7&=-a|k~  
Thread.sleep(nSecond); fm[_@L% x  
} bkxk i@t  
catch(Exception e) Oi6f8*,  
{ U.HoFf+HN  
e.printStackTrace (); F\zkyk4  
} #,7eQaica  
} f2`P8$U)R  
t1G1(F#&%  
//日志 E"G:K`Q  
public static void log(String sMsg) dK[*
 
{ =fL6uFmxI@  
System.err.println(sMsg); aytq4Ts  
} X\o/i\ C}  
F_ ,L2J  
J'I1,5(  
public static void log(int sMsg) P'-JbPXU  
{ $o/0A
 
System.err.println(sMsg); C}n[?R  
} i7i|370  
} {E;2&d  
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/* b24NL'jm  
**TestMethod.java <QYCo1_  
*/ N$N;Sw  
package NetFox; JZs|~@  
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6  
MV Hz$hy
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public class TestMethod { 7JxE|G  
L4\SBO  
S^3g]5YX  
public TestMethod() 54`bE$:+  
{ ///xx/weblogic60b2_win.exe 9\AEyaJFZ  
try{ B, QC-Tn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FBR$,j;Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3%It~o?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `ENlV9  
fileFetch.start(); OVDMC4K2z!  
} Zp/qs z(]  
catch(Exception e){e.printStackTrace ();} g_rA_~dh  
s|{^ }4{  
,Hik(22  
} xTa4.ZXg  
sh',"S#=@  

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public static void main(String[] args) .fio<mqi  
{ 5@w'_#!)  
new TestMethod();
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} 1Y H4a|bc  
} adRNrt*!  
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