http断点续传简单实现（java)

/* y jQpdO  
**SiteFileFetch.java VSQxlAGk@  
*/ /'WVRa  
package NetFox; &XH{,fv$  
import java.io.*; S)~Riuy$  
import java.net.*; B%^ $fJ|  
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public class SiteFileFetch extends Thread { zm`^=cV  
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~ @Au<  
SiteInfoBean siteInfoBean = null; //文件信息Bean n3LCQ:]Tf  
long[] nStartPos; //开始位置 xK;WJm"  
long[] nEndPos; //结束位置 Ii4lwZnz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 mIUpAOC`"Z  
long nFileLength; //文件长度 7\p<k/TS  
boolean bFirst = true; //是否第一次取文件 +'f38D*  
boolean bStop = false; //停止标志 '@ C\,E  
File tmpFile; //文件下载的临时信息 pGhA  
DataOutputStream output; //输出到文件的输出流 3t^r;b  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^"hsbk&Yu  
public SiteFileFetch(SiteInfoBean bean) throws IOException "J(7fL$!  
{ T.R(  
siteInfoBean = bean; j@b18wZ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2Y'=~*tV  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d/3 k3HdL  
if(tmpFile.exists ()) 8 ?+t+m[  
{ M+q|z0U  
bFirst = false; >xa k  
read_nPos(); 4zw5?$YWO"  
} #w<:H1,4
 
else jf'#2-   
{ BoMf#l.3B  
nStartPos = new long[bean.getNSplitter()]; KXy|Si8w  
nEndPos = new long[bean.getNSplitter()]; ob3Z I  
} l|onH;g\  
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} #H1ng<QV  
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public void run() 5 LZ+~!2+  
{ '5vgpm
n  
//获得文件长度 4lqowg0  
//分割文件 q>X%MN y  
//实例FileSplitterFetch h0)Wy>B=,  
//启动FileSplitterFetch线程 qp@:Zqz8  
//等待子线程返回 wt@q+9:  
try{ {}TR'Y4  
if(bFirst) R0v5mD$:G  
{ z9#iU>@  
nFileLength = getFileSize(); -{A!zTw1w  
if(nFileLength == -1) *0aU(E#  
{ 6 NJ5v+  
System.err.println("File Length is not known!"); WV'FW)%  
} G()- NJ{  
else if(nFileLength == -2) aH1mW;,1u  
{
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System.err.println("File is not access!"); k 8Swra?j  
} k!lz_Y  
else l'2a?1/q  
{ kN)m"}gX  
for(int i=0;i<nStartPos.length;i++) ~+GMn[h  
{ LOkNDmj  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6k=ink-/  
} T"2D<7frbo  
for(int i=0;i<nEndPos.length-1;i++) ;&Oma`Ec  
{ <Eo;CaaF/  
nEndPos = nStartPos[i+1]; _e;$Y#`EO  
} z$d/Vz,a  
nEndPos[nEndPos.length-1] = nFileLength; ,\FJVS;NeJ  
} Y M_\ ZK:  
} i-b++R/WN  
7xOrG],E  
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//启动子线程 JKkR963 O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P*#H]Pv  
for(int i=0;i<nStartPos.length;i++) %-6I  
{ ]B<Hrnn  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [V5ebj:6w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Bk~lE]Q3c7  
nStartPos,nEndPos,i); ,\|W,N}~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9W{=6D86e  
fileSplitterFetch.start(); }lk_Oe1  
} 8W]6/st?]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pOCLyM9c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ueiXY|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Q`Q%;%t  
nEndPos = " + nFileLength); tBp146`  
// fileSplitterFetch[nPos.length-1].start(); GB(o)I#h  
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//等待子线程结束 R^.oM1qu|  
//int count = 0; =-`}(b2N  
//是否结束while循环 *:q3<\y{  
boolean breakWhile = false; pN)9GO5  
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S  
l!plw,PYC  
while(!bStop) &sp7YkaW  
{ P8Bv3  
write_nPos(); pr8eRV!x  
Utility.sleep(500); dooS
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breakWhile = true; HXTB
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for(int i=0;i<nStartPos.length;i++)
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{ oyBBW?m  
if(!fileSplitterFetch.bDownOver) ;~
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{ S=>54!{`x  
breakWhile = false; S;[*5g6a&x  
break; &i8AB{OU  
} Y. ]FVq  
} 4+od
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if(breakWhile) 1Z?en  
break; :h tOz.  
P"J(O<(1-:  
4|uh&4"*@W  
//count++; 6uCa iPV  
//if(count>4) k[]B P4  
// siteStop(); %X Jv;|  
} zo-hH8J:  
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Vf#X[$pc/  
System.err.println("文件下载结束！"); W>Eee?  
} #YM5P  
catch(Exception e){e.printStackTrace ();} [V~(7U  
} /R&!92I0*  
 y#5xS  
#Mt'y8|}$  
//获得文件长度 V]cD^Fqp  
public long getFileSize() bwG2=  
{ ^[noGjy  
int nFileLength = -1; 84UH& b'n  
try{ G};os+FxF  
URL url = new URL(siteInfoBean.getSSiteURL()); +_tK \MN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $R3]y9`?  
httpConnection.setRequestProperty("User-Agent","NetFox"); P%A^TD|  
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.az+'1  
int responseCode=httpConnection.getResponseCode(); vT V'D&x2  
if(responseCode>=400) 3%Z:B8:<y  
{ tr6<89e(o  
processErrorCode(responseCode); r#^/qs(~  
return -2; //-2 represent access is error P#(BdKjM  
} ~ztsR;iL  
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String sHeader; bT<if@h-  
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for(int i=1;;i++) )-q#hY  
{ dd#=_xe  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \jDD=ew  
//Utility.log(in.readLine()); ufE;rcYE  
sHeader=httpConnection.getHeaderFieldKey(i); >NWrT^rk
 
if(sHeader!=null) A*jU&3#  
{ M=$ qus  
if(sHeader.equals("Content-Length")) zdFO&YHTw  
{ ?El8:zt?|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _FXvJ}~m  
break; f]MKNX  
} )?#*GMWU  
} U}ei2q\  
else SFVOof#s  
break; ~Rd,jfx  
} _KBN  
} j^#4!Ue  
catch(IOException e){e.printStackTrace ();} @:u>  
catch(Exception e){e.printStackTrace ();} S)T]>Ash  
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@
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Utility.log(nFileLength); r>4HF"Nm  
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return nFileLength; :ulOG{z  
} H`#{zt);  
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//保存下载信息（文件指针位置） ol QT r  
private void write_nPos() 6%bZZTP`  
{ w&yK*nBK  
try{ c5x2FM z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1p&e:v  
output.writeInt(nStartPos.length); ]hNio6CVm  
for(int i=0;i<nStartPos.length;i++) (}Ob
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{ Y5nj _xQJL  
// output.writeLong(nPos); ~NT2QY5!K  
output.writeLong(fileSplitterFetch.nStartPos); eT33&:n4  
output.writeLong(fileSplitterFetch.nEndPos); )Qe<XJH!  
} 77D>;90>?  
output.close(); jFbj)!;  
} h3-y}.VjG  
catch(IOException e){e.printStackTrace ();} Bx9R!u5D  
catch(Exception e){e.printStackTrace ();} :.8@ xVH  
} Dv~W!T i  
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//读取保存的下载信息（文件指针位置） \)KLm  
private void read_nPos() RCM;k;@8V  
{ 1vKAJ<4W  
try{ FXMrD,qVg  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Qh*"B  
int nCount = input.readInt(); P2la/jN  
nStartPos = new long[nCount]; bMe/jQuL.$  
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) gR7in!8  
{ D%[yAr;r  
nStartPos = input.readLong(); mX8k4$z  
nEndPos = input.readLong(); .[mI9dc  
} ?
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input.close(); v@m2c_,  
}
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catch(IOException e){e.printStackTrace ();} O5X@'.#rU  
catch(Exception e){e.printStackTrace ();} in
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} z~8`xn,  
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private void processErrorCode(int nErrorCode) P){b"`f  
{ $?x;?wS0V  
System.err.println("Error Code : " + nErrorCode); -|F(qf  
} fcaUj9qN  
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vwF#;jj\  
//停止文件下载 O_vCZW a3  
public void siteStop() jEK{QOq0  
{ h{xq  
bStop = true; f/"
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for(int i=0;i<nStartPos.length;i++) }Pi}? 41!  
fileSplitterFetch.splitterStop(); M N-j$-y}  
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} olA 1,8  
} m2sf]-?Y  
//负责部分文件的抓取 ^@91BY  
**FileSplitterFetch.java Hs9; &C  
*/ $TU:iv1Fm  
package NetFox; Dx1f<A1  
=74yhPAW  
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import java.io.*; K/T4T\  
import java.net.*; dZ6\2ok+  
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public class FileSplitterFetch extends Thread { oGIh:n7 q+  
Nqy)jfyex  
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String sURL; //File URL !+R_Z#gB  
long nStartPos; //File Snippet Start Position r<)>k.] !  
long nEndPos; //File Snippet End Position ][D/=-  
int nThreadID; //Thread's ID 8PRKSJ[@K  
boolean bDownOver = false; //Downing is over (~k{aO  
boolean bStop = false; //Stop identical |$^a"Yd`9  
FileAccessI fileAccessI = null; //File Access interface BYuoeN!  
^RIDC/B=V6  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException rjaG{ i  
{ rlRRGJ\l  
this.sURL = sURL; au+6ook
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this.nStartPos = nStart; a ]b%v9  
this.nEndPos = nEnd; "gIjU~'A  
nThreadID = id; $bo,m2)  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \I-bZ|^  
} n0 q$/Y.  
PR+L6DT_  
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public void run() l|jb}9(J  
{ i3dV2^O  
while(nStartPos < nEndPos && !bStop) cXDG(.!n7B  
{ K?J?]VCw  
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try{ V#Pz`D  
URL url = new URL(sURL); (_ TKDx_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qA;!P
ql`  
httpConnection.setRequestProperty("User-Agent","NetFox"); y+aL5$x6  
String sProperty = "bytes="+nStartPos+"-"; UL3++bt  
httpConnection.setRequestProperty("RANGE",sProperty); c{(4s6D  
Utility.log(sProperty); Bk yW
 
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InputStream input = httpConnection.getInputStream(); TGuvyY  
//logResponseHead(httpConnection); FfSKE  
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byte[] b = new byte[1024]; dN)@/R^E;  
int nRead; :c/](M  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o0B3
G
  
{ [j;#w,Wb  
nStartPos += fileAccessI.write(b,0,nRead); 7dh--.i  
//if(nThreadID == 1) hsJS(qEh.'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~IQ2;

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} IEj=pI  
,b${3*PPQ  
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Utility.log("Thread " + nThreadID + " is over!"); <&m `)FJ  
bDownOver = true; HUWCCVn&  
//nPos = fileAccessI.write (b,0,nRead); +cf.In,{  
} <8sy*A?0z  
catch(Exception e){e.printStackTrace ();} Su>UXuNdE#  
} O_^X:0}  
} "raC?H  
z$]HZ#aRE  
p6*|)}T_%  
//打印回应的头信息 Kc#42C;t/  
public void logResponseHead(HttpURLConnection con) IzWS6!zKU  
{ Qh{]gw-6  
for(int i=1;;i++) ".|?A9m_  
{ XKEbK\  
String header=con.getHeaderFieldKey(i); Op 0Qpn  
if(header!=null) HLYo+;j3|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); N1l&$#Fr!s  
Utility.log(header+" : "+con.getHeaderField(header)); *{%d{x}l  
else $g@-WNe  
break; |)pgUI2O[  
} "v[?`<53^l  
} -MTO=#5z  
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public void splitterStop() .4cOMiG  
{ MU#$tXmnC  
bStop = true; \+I+Lrj%  
} &h67LMD!  
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} eT ZQ[qMp  
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8pE0ANbq  
/* MoP,a9p  
**FileAccess.java j|c6BdROl  
*//文件访问(定位，写) M\w%c5  
package NetFox; =2tl149m/z  
import java.io.*; uJ_"g
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@;T?R  
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public class FileAccessI implements Serializable{ +f]\>{o4  
@uzzyp r>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;=oGg%@aP  
RandomAccessFile oSavedFile; dq U.2~9  
long nPos; *JmU",X  
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?
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public FileAccessI() throws IOException _>)=c<HL  
{ z;KUIWg  
this("",0); v:w $l{7  
} =^D{ZZ
w{  
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uom~,k$|  
public FileAccessI(String sName,long nPos) throws IOException /ar/4\b  
{ _!'sj=n]q  
oSavedFile = new RandomAccessFile(sName,"rw"); _0c$SK  
this.nPos = nPos; wG2-,\:  
oSavedFile.seek(nPos); Q{))+'s2h  
} 'h~I#S4!  
EHC^ [5  
#{L !o5  
public synchronized int write(byte[] b,int nStart,int nLen) q oJ4w7  
{ Ze>Pg.k+  
int n = -1; 'RjMwJy{  
try{ M~ ^ {S[o  
oSavedFile.write(b,nStart,nLen); ZPolE_P
7  
n = nLen; JJn+H&[B  
} i[M]d`<36  
catch(IOException e) kFi^P~3D[  
{ J&jNONu?  
e.printStackTrace (); 8OW504AD  
} h1uD>heGl  
c$
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return n; TV&4m5  
} {aRZBIv  
H%:u9DlEK/  
|}y6U< I  
} 5NECb4FG  
.1 =8c\%  
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/* 7Yjxx+X9  
**SiteInfoBean.java 05>xQx?"m4  
*/ av*M#  
package NetFox; gc6T`O-_;  
0XNj!^&  
T2$V5RyX  
public class SiteInfoBean { .
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!agtgS$qII  

/\B[lRn  
private String sSiteURL; //Site's URL gUq)M  
private String sFilePath; //Saved File's Path :%hxg  
private String sFileName; //Saved File's Name ~"ij,Op,3  
private int nSplitter; //Count of Splited Downloading File yt-F2Z&  
k-M-=VvA  
W%k0_Y/5  
public SiteInfoBean() P=jbr"5Q:  
{//nSplitter的缺省值为5 U2(|/M+  
//default value of nSplitter is 5 [!v| M  
this("","","",5); cLD
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} i%R2#F7I  
]&D;'),   
Q
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;%R+]&J  
{ vj:hMPC ZM  
sSiteURL= sURL; g}hR q%  
sFilePath = sPath; qt#a_F*rV  
sFileName = sName; (n~e2tZ/  
this.nSplitter = nSpiltter; 7 i|_PP_  
;7]Q'N  
u/h!i@_w[  
} jKcnZu  
2Rp'ju~O)/  
pSq3\#Twr  
public String getSSiteURL() )n[ oP%  
{ GAlAFsB  
return sSiteURL; N!e?K=}tL  
} Dl#%tYL+3h  
w C0fPPeA  
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public void setSSiteURL(String value) |Gw[vY  
{ /?; 8F  
sSiteURL = value; _S(]/d(c
 
} 5[Ryc[  
uT}Jw  
| ZI~#V  
public String getSFilePath() 9%?'[jJ  
{ h69: Tj!  
return sFilePath; \c! LC4pE  
} FH'jP`  
Y.Er!(pz  
jnK8 [och  
public void setSFilePath(String value) kd9GHN;7  
{ G
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sFilePath = value; 1{-W?n  
} _cZ`7]Z  
'xdM>y#S  
R;X8%'  
public String getSFileName() NAj1ORy4pX  
{ s68EzFS  
return sFileName; 9GdrJ~h  
} S!GjCog^J  
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#pxc6W /  
public void setSFileName(String value) @5%cP  
{ !P, 9Sg&5)  
sFileName = value; <:u)C;  
} ,uD>.->  
2&W(@wT$  
-A
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public int getNSplitter() F*QD\sG:  
{ =GQ?P*x|$  
return nSplitter; j~G^J  
} vO1P%)  
E5lC'@Dcz  
#;RP ?s  
public void setNSplitter(int nCount) C61KY7iyR  
{ '"5"$)7  
nSplitter = nCount; Z;@F.r  
} Y.?|[x0Wh  
} XHO}(!l\  
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/* ^c1I'9(r5  
**Utility.java i&^?p|eKa  
*/ VwoCRq*  
package NetFox; W|T"'M_  
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public class Utility { unmuY^+<  
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{Gs&u>>R"^  
public Utility() 4yC{BRbi  
{ VG'oy  
/D_8uTS>d[  
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} fp9ksxb@m  
x
ZS  
//线程睡眠 :H<u@%  
public static void sleep(int nSecond) p;) ;Vm+8  
{ -o F#a 8  
try{ pF.Ws,nQ5  
Thread.sleep(nSecond); n(a7%Hx2  
} F5%-6@=  
catch(Exception e) 3vOI=ar=L~  
{ +I2
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e.printStackTrace (); pM\)f  
} B4&@PX"'>,  
} r{kV*^\E  
tqrvcnQr^  
//日志 T}P|uP  
public static void log(String sMsg) /'G'GQrr  
{ (@M=
W.M#  
System.err.println(sMsg); H(]lqvO  
} 6(oGU4  
h GS";
g[?  
KbH#g>.oB  
public static void log(int sMsg) [kFX>G4  
{ ~sAINV>A  
System.err.println(sMsg);
mn" a$  
} 7 .+kcqX  
} S'Q$N-Dy  
Y_%\kM?7  
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/* "[H9)aAj7  
**TestMethod.java &}w,bG$  
*/ Q=g
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package NetFox; 8ne'x!1 D  
_Ux>BJmP  
AUoi$DF(@  
public class TestMethod { M.d{:&@`%  
622mNY  
ms ;RJT2O'  
public TestMethod() Q%QpG)E  
{ ///xx/weblogic60b2_win.exe nI.#A  
try{ rN{&$+"2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %dL|i2+*8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "=|yM~V  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u[s+YGS  
fileFetch.start(); \{G6!dV|S  
} ^gkyi/z  
catch(Exception e){e.printStackTrace ();} 8c__ U<  
2Pi}<pG~
 
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} QsDab4  
?Dm!;Z+7  
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public static void main(String[] args) DfV_0
8  
{ wGISb\rr  
new TestMethod(); ffm19B=  
} J;"XRE[%5  
} MkJL9eG  
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