http断点续传简单实现（java)

/* zQ %z"tQ  
**SiteFileFetch.java \(U"_NPp  
*/ UAXF6
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package NetFox; KSB_%OI1  
import java.io.*; giPo;z\c  
import java.net.*; nf.:
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public class SiteFileFetch extends Thread { +[8Kl
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SiteInfoBean siteInfoBean = null; //文件信息Bean ;(0(8G  
long[] nStartPos; //开始位置 Zjic"E1  
long[] nEndPos; //结束位置 ml33qXW:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H@2"ove-uC  
long nFileLength; //文件长度 .4C[D{4  
boolean bFirst = true; //是否第一次取文件 H(G^O&ppdB  
boolean bStop = false; //停止标志 hp]ng!I{\u  
File tmpFile; //文件下载的临时信息 n]C%(v!u3  
DataOutputStream output; //输出到文件的输出流 cv*Q]F1%  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） IgiF,{KE,  
public SiteFileFetch(SiteInfoBean bean) throws IOException QTjftcu  
{ ?%xhe  
siteInfoBean = bean; m,gy9$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); W93JY0Ls9|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :ONuWNY N  
if(tmpFile.exists ()) s\Pt,I@Y_  
{ h-b5   
bFirst = false; 0ve`  
read_nPos(); P7wqZ?  
} OSa
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else ^?s~Fk_V  
{ P"bknXL  
nStartPos = new long[bean.getNSplitter()]; u JQaHL!  
nEndPos = new long[bean.getNSplitter()]; &vFqe,Z  
} ||=[kjG~  
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} KM/U?`6>:  
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public void run() >d{dZD}  
{ Q&Z4r9+Z  
//获得文件长度 /UpD$,T|^|  
//分割文件 5?5-;H  
//实例FileSplitterFetch <'}b*wUB  
//启动FileSplitterFetch线程 v
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//等待子线程返回 W,HH *!  
try{ 4fw1_pv_D  
if(bFirst) #+K
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{ AXl!cgi  
nFileLength = getFileSize(); 1p7cv~#95  
if(nFileLength == -1) ~!]&>n;=G  
{ PPoI>J  
System.err.println("File Length is not known!"); 'yPCZ`5H(  
}  <+AIt  
else if(nFileLength == -2) .M9d*qp`S  
{ Pz]bZPHn  
System.err.println("File is not access!"); Hp)X^O"  
} w]>"'o{{  
else M.ZEqV+
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{ -}{%Q?rYj  
for(int i=0;i<nStartPos.length;i++) vKNt$]p
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{ =\
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); r]A"Og_U  
} b8J@K"
 
for(int i=0;i<nEndPos.length-1;i++) hLb;5u&!kW  
{ =?/N5O(  
nEndPos = nStartPos[i+1]; "?apgx 6  
} Qq#Ff\|4u(  
nEndPos[nEndPos.length-1] = nFileLength; %55@3)V8Rf  
} zRwb"  
} QS3U)ZO$@  
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//启动子线程 &|v{#,ymeb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $/u1chf  
for(int i=0;i<nStartPos.length;i++) "pt+Fe|@c;  
{ M]}l^m>L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kTnOmAw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ne3R.g9;Z  
nStartPos,nEndPos,i); pv$mZi4i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _i5mC,OffN  
fileSplitterFetch.start(); q`XW5VV{K  
} 1hl
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =EQJqj1T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Aj[?aL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e# t3u_  
nEndPos = " + nFileLength); KX!i\NHz  
// fileSplitterFetch[nPos.length-1].start(); <3d;1o  
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m23+kj)+VY  
//等待子线程结束 dXmV@ Noo  
//int count = 0; K*
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//是否结束while循环 pgT9hle/  
boolean breakWhile = false; wMGk!N  
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while(!bStop) x<)G( Xe*  
{ Bs[nV}c>>  
write_nPos(); z
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Utility.sleep(500); 'l~6ErBSg  
breakWhile = true; BPqk"HG]T  
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for(int i=0;i<nStartPos.length;i++) -D^L}b  
{ " Ya9~6  
if(!fileSplitterFetch.bDownOver) Ir5WN_EaS  
{ ibJHU@l  
breakWhile = false; Ow3P-UzU3  
break; bLqy!QE  
} FXV`9uq}Z  
} P-CB;\  
if(breakWhile) V }>n  
break; Y>BP?l  
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//count++; $+cAg>  
//if(count>4) RW_q~bA9  
// siteStop(); ,m^;&&  
} vfcb:x  
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System.err.println("文件下载结束！"); n,j$D62[  
} iEIg
:  
catch(Exception e){e.printStackTrace ();} PmR*}Aw  
} ^N{ltgQY  
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//获得文件长度 ow6*Xr8eQ  
public long getFileSize() #?[.JD51l  
{ W2Luz;(U  
int nFileLength = -1; aRJcSV  
try{ v>A=2i*j  
URL url = new URL(siteInfoBean.getSSiteURL()); "w_N'-}#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @]HXP_lyD/  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6Pn8f  
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pFsc}R/0/8  
int responseCode=httpConnection.getResponseCode(); '9?;"=6(  
if(responseCode>=400) 9}29&O  
{ GiFXX  
processErrorCode(responseCode); re &E{  
return -2; //-2 represent access is error G{9X)|d  
} x;\wY'  
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#~L h#  
String sHeader; 2Y!S_Hw8  
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for(int i=1;;i++) !yOeW0/2[  
{ &o3K%M;C?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w}R~C  
//Utility.log(in.readLine()); "xRBE\B
 
sHeader=httpConnection.getHeaderFieldKey(i); QK`i%TXJ  
if(sHeader!=null) }/P5>F<H[  
{ 5S{7En~zUE  
if(sHeader.equals("Content-Length")) ul f2vD  
{ fV:4#j  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 76cG90!Z  
break; Rli:x  
} Mwp$  
} m
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else fq[;%cr4  
break; {nT^tAha  
} u{N,Ib 8  
} <#GB[kQa  
catch(IOException e){e.printStackTrace ();} BvrB:%_:  
catch(Exception e){e.printStackTrace ();} 9`//^8G:=  
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Utility.log(nFileLength); ORXm&z)  
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return nFileLength; dC\ZjZZ  
}
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//保存下载信息（文件指针位置） G$0c'9d*(  
private void write_nPos() $;M:TpX  
{ #GDe08rOw  
try{ @~c6qh  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ##Q/I|  
output.writeInt(nStartPos.length); =0;}K@(J  
for(int i=0;i<nStartPos.length;i++)  c gz
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{ /&F,
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// output.writeLong(nPos); AcI,N~~  
output.writeLong(fileSplitterFetch.nStartPos); \)K^=jM  
output.writeLong(fileSplitterFetch.nEndPos); ;,i]w"*  
} Uj+j}C  
output.close(); \I"Z2N>^z  
} b"!Q2S~  
catch(IOException e){e.printStackTrace ();} pj4!:{.;  
catch(Exception e){e.printStackTrace ();} o9xlu.QL{c  
} aLJ(?8M@  
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//读取保存的下载信息（文件指针位置） F:y[@Yn  
private void read_nPos() E9?phD  
{ \AL f$88>@  
try{ l]~n3IK"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I;VuW  
int nCount = input.readInt(); `n$5+a+  
nStartPos = new long[nCount]; VJ ^dY;  
nEndPos = new long[nCount]; upj]6f"(  
for(int i=0;i<nStartPos.length;i++) b'6-dU%  
{ nhIa175'  
nStartPos = input.readLong(); ^rvx!?zO  
nEndPos = input.readLong(); pv^O"Bs  
} n,B,"\fw  
input.close(); *@d&5  
} `tjH<  
catch(IOException e){e.printStackTrace ();} p-1 3H0Kt  
catch(Exception e){e.printStackTrace ();} r$]HIvJD  
} Gmf B  
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private void processErrorCode(int nErrorCode) |9~GM  
{ k)TSR5
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System.err.println("Error Code : " + nErrorCode); _`64gS}^  
} pABs!A`N  
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//停止文件下载 Bz5-ITX   
public void siteStop() a'!zG cT  
{ XJLQ{  
bStop = true; 6252N]*  
for(int i=0;i<nStartPos.length;i++) =XXZ?P  
fileSplitterFetch.splitterStop(); Duc#$YfGm  
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} nu'M 39{  
} X/N0LU
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//负责部分文件的抓取 !9xp c
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**FileSplitterFetch.java |j 6OM{@  
*/ MNSbtT*^  
package NetFox; M`ip~7"  
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import java.io.*; ?.D3'qv  
import java.net.*; ar:+;.n  
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public class FileSplitterFetch extends Thread { /% kY0 LY  
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String sURL; //File URL ^a#X9  
long nStartPos; //File Snippet Start Position -YsLd 9^4  
long nEndPos; //File Snippet End Position ATR!7i\|  
int nThreadID; //Thread's ID 8>7&E-  
boolean bDownOver = false; //Downing is over 9'r:~O  
boolean bStop = false; //Stop identical (&!NC[n,  
FileAccessI fileAccessI = null; //File Access interface s+Q~~]HJM  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4fe7U=#;Y  
{ p1vp8p
 
this.sURL = sURL; _U/!4A  
this.nStartPos = nStart; X,LD   
this.nEndPos = nEnd; Ntbg`LGf'!  
nThreadID = id; 8cA~R-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7^g&)P  
} &8z[`JW,T  
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public void run() nB!&Zq  
{ @WI2hHD  
while(nStartPos < nEndPos && !bStop) 2Y7)WPn  
{ &\Amn?Iq  
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try{ J.8IwN1E  
URL url = new URL(sURL); F}=aBV|-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); DoeiW=  
httpConnection.setRequestProperty("User-Agent","NetFox"); !=N"vD*  
String sProperty = "bytes="+nStartPos+"-"; *f?4   
httpConnection.setRequestProperty("RANGE",sProperty); /FIE:Io  
Utility.log(sProperty); [3@):8  
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InputStream input = httpConnection.getInputStream(); 'z[Sp~I\  
//logResponseHead(httpConnection); o";Z$tAJkC  
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byte[] b = new byte[1024]; *Q,0W:~-  
int nRead; (x3.poSt  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) IEzaK  
{ nI*v820,  
nStartPos += fileAccessI.write(b,0,nRead); 1u6^z  
//if(nThreadID == 1) IhA*"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +mp@b942*  
} ,j$Vvz  
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Utility.log("Thread " + nThreadID + " is over!"); y8rm  
bDownOver = true; >mjNmh7  
//nPos = fileAccessI.write (b,0,nRead); Zib)P&  
} zNIsf"  
catch(Exception e){e.printStackTrace ();} ~>+]%FPv  
} .;*s`t  
} dtcIC0:[  
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//打印回应的头信息 6CMub0  
public void logResponseHead(HttpURLConnection con) $n^gmhp  
{ I:d[Q s  
for(int i=1;;i++) 1)[]x9]^q'  
{ /)>s##p*  
String header=con.getHeaderFieldKey(i); g'|MA~4yB  
if(header!=null) aM$W*-Y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 14"J d\M8  
Utility.log(header+" : "+con.getHeaderField(header)); /
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else 4M^G`WA}t9  
break; !1G."fo  
} ]TyisaT  
} )u
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public void splitterStop() HO''&hz  
{ ;jipe3LU  
bStop = true; 37RLE1Yf  
} %3$*K\Ai  
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} &|`C)6[C  
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@S7sr-  
/* A+UU~?3y  
**FileAccess.java u@4V7;L  
*//文件访问(定位，写) 59Gk3frk(  
package NetFox; e A}%C.ZR  
import java.io.*; @_LN3z
P  
is@b&V]  
%
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public class FileAccessI implements Serializable{ vC5n
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s|NjT  
RandomAccessFile oSavedFile; Q[d}J+l4{  
long nPos; V3ndV-uQE  
+/ &_v^sC;  
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public FileAccessI() throws IOException W mm4hkf  
{ Z?O*'#yn  
this("",0); Ii:>xuF&  
} DSj(]U~r  
k`x=D5s\  
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public FileAccessI(String sName,long nPos) throws IOException L=8+_0  
{ "t0kAG  
oSavedFile = new RandomAccessFile(sName,"rw"); M5trNSL&u  
this.nPos = nPos; TET`b7G  
oSavedFile.seek(nPos); 2"-S<zM  
} JO@|*/mL  
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public synchronized int write(byte[] b,int nStart,int nLen) Kb^>-[Yx  
{ Y1arX^Zb  
int n = -1; "rAY.E]  
try{ NzW`B^p  
oSavedFile.write(b,nStart,nLen); :F?x)"WoQ+  
n = nLen; x[Wwq=~  
} 1lpw
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catch(IOException e) Ia'ZV7'  
{ w2xG_q  
e.printStackTrace (); /N-_FMl?  
} ;zdxs'hJ  
{bPV)RL:  
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return n; @K:N,@yq  
} YQ0)5}  
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} O$ HBO  
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/* x3zj?-  
**SiteInfoBean.java RJeSi`19T)  
*/ 7_# 1Ec|;  
package NetFox; {>bW>RO)  
Ux2U*a;  
/xJqJ_70X  
public class SiteInfoBean { mw^7oO#  
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c={Ft*N  
private String sSiteURL; //Site's URL Xe+,wW3YF  
private String sFilePath; //Saved File's Path Ac|5. ?|N  
private String sFileName; //Saved File's Name :3$}^uzIq  
private int nSplitter; //Count of Splited Downloading File -xD*tf*  
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public SiteInfoBean() 90xk$3(
 
{//nSplitter的缺省值为5 C_LvZ=  
//default value of nSplitter is 5 ~LQ[4h<J !  
this("","","",5); voe7l+Xk  
} m%#`y\]I  
~}DQT>7$  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) bY~@}gC**@  
{ 3I 0eW%,  
sSiteURL= sURL; q*)+K9LRk  
sFilePath = sPath; _DP|-bp D  
sFileName = sName; +1 eCvt:,  
this.nSplitter = nSpiltter; z{]?h cY  
V84*0&qOW  
4FMAz^  
} rgcWRt  
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R\s!*)  
public String getSSiteURL() x6'^4y])  
{ TQ9D68 ,  
return sSiteURL; 1f(DU4h  
} $A<ESfrs  
C0x"pO7  
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public void setSSiteURL(String value) eUO9a~<  
{ KbxR Lx]w  
sSiteURL = value; Rn+4DcR  
} 99 wc  
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public String getSFilePath() +1;'B4  
{ X21dX`eMN  
return sFilePath; B>TSdn={>  
} G\iyJSj[P  
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public void setSFilePath(String value) %kU'hzLg  
{ ;8B.;%qkL  
sFilePath = value; ~S(^T9R  
} $->d!  
[B6DC`M  
d$;/T('  
public String getSFileName() yFpySvj}  
{ d34Y'r  
return sFileName; Nw]
("
.  
} LAZVW</  
IjZ@U%g@;  
BgRZ<B`  
public void setSFileName(String value) #o[\Dwu  
{ .gT4_  
sFileName = value; E`@43Nz  
} kR6A3?[  
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public int getNSplitter() `Q9+k<  
{ 5()Fvae{k  
return nSplitter; i7eI=f-
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} |f NMs  
aR:<<IF\  
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public void setNSplitter(int nCount) zk>h u<_  
{ ndOfbu;mf  
nSplitter = nCount; \p6 }  
} .C5@QKU  
} GNghB(  
yDtOpM8<{  
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/* *]{=8zc2  
**Utility.java H`D f  
*/ 97x%w]kV  
package NetFox; (2%>jg0M  
%N{sD[^  
2X_>vIlEm  
public class Utility { qeMv Vf  
.;slrg(5F  
#Wx=v$"  
public Utility() 'rx?hL3VW  
{ SOI)/u  
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} D-iUN  
b"P&+c  
//线程睡眠 c *1S}us  
public static void sleep(int nSecond) y
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{ T?e9eYwS  
try{ Ma_=-cD  
Thread.sleep(nSecond); 1(pjVz&  
} (txt8q  
catch(Exception e) @Mr}6x*  
{  VIYV92[  
e.printStackTrace (); IQoH@l&Xk  
} j]HE>  
} t 2G1[j!  
Z~R
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//日志 r./z,4A`  
public static void log(String sMsg)  wQw-:f-  
{ zf7rF}  
System.err.println(sMsg); LK %K0o  
} Vs|sw  
:@WLGK*u.  
PAr|1i)mB  
public static void log(int sMsg) F_ _H(}d  
{ s79q5  
System.err.println(sMsg); sM0c#YK?  
} <%/:w/  
} !4L#$VG  
G ;jF9i  
#B\B(y  
/* &R0OeRToUb  
**TestMethod.java ,?fN#gc :  
*/ |9x%gUm  
package NetFox; T[m ~6  
I=K[SY,]9  
G
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public class TestMethod { :(+]b  
U* 4{"  
N]V/83_  
public TestMethod() OM1*I
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{ ///xx/weblogic60b2_win.exe E+:.IuXW$  
try{ !>q?dhw@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,v|CombIc.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }]tFz}E\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jjYM3LQcdP  
fileFetch.start(); kz$(V(k<  
} m&,bC)}  
catch(Exception e){e.printStackTrace ();} i+U@\:=  
6xyY+  
m\/>C|f\  
} P4i3y{
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public static void main(String[] args) 5DmCxg  
{ Ck:#1-t8{  
new TestMethod(); zUNH8=U  
} _r~!O$2  
} 5XI;<^n2  
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