http断点续传简单实现（java)

/* $W_sIS0\z  
**SiteFileFetch.java MgpjC`  
*/ *
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package NetFox; QVT|6znw  
import java.io.*; Pi/V3D)B  
import java.net.*; qS|ns'[  
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public class SiteFileFetch extends Thread { LZ'Y3 *  
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SiteInfoBean siteInfoBean = null; //文件信息Bean /TEE<\"  
long[] nStartPos; //开始位置 0(o{V:l%Z|  
long[] nEndPos; //结束位置 nNc>nB1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 eVRPjVzQ'Q  
long nFileLength; //文件长度 Y'&rSHI"  
boolean bFirst = true; //是否第一次取文件 P >>VBh?  
boolean bStop = false; //停止标志 +H**VdM6s  
File tmpFile; //文件下载的临时信息 ;ElwF&"!X  
DataOutputStream output; //输出到文件的输出流 OyG#
 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 'nQQqx%v  
public SiteFileFetch(SiteInfoBean bean) throws IOException (qyT,K8  
{ UD0#Tpd7  
siteInfoBean = bean; HSG7jC'_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); YJm64H,[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v\ <4y P  
if(tmpFile.exists ()) -]~KQvIH!  
{ qGkD] L  
bFirst = false; )<K3Fz Bs  
read_nPos(); Sv>bU4LHf  
} 5fDp"-  
else a<CJ#B2K  
{ bAwFC2jO[  
nStartPos = new long[bean.getNSplitter()]; Ox%.We5  
nEndPos = new long[bean.getNSplitter()]; pPH"6   
} GOU>j"5}2  
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} 6` 4,  
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public void run() /oC@:7  
{ .T*89cEu  
//获得文件长度 M $\!SXL  
//分割文件 8S#TOeQ  
//实例FileSplitterFetch /VHQ!Wi  
//启动FileSplitterFetch线程 @3_."-
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//等待子线程返回 /I~(*X  
try{ )\m%&EXG{  
if(bFirst) ,cFBLj(@  
{ :TRhk.  
nFileLength = getFileSize(); q c DJ  
if(nFileLength == -1) %(ms74R+  
{ %T,cR>lw  
System.err.println("File Length is not known!"); 8dlhL8#  
} k`=&m"&#  
else if(nFileLength == -2) ['_W<  
{ p"|0PlW  
System.err.println("File is not access!"); 7*(K%e"U  
} 3FsX3K,_X  
else fD~f_Wr  
{ 1qE*M7_:E>  
for(int i=0;i<nStartPos.length;i++) +L-(Lz[p  
{ Q60'5Wt  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); il~A(`+YO  
} 4YyVh.x  
for(int i=0;i<nEndPos.length-1;i++) ;dquld+q  
{ bF c %  
nEndPos = nStartPos[i+1]; `2a7y]?  
} [;
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nEndPos[nEndPos.length-1] = nFileLength; 8fC5O  
} 6g 5Lf)yG  
} 4|/=]w  
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c;doxNd6  
//启动子线程 gT#hF]c:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; SGUZ'}  
for(int i=0;i<nStartPos.length;i++) +qee8
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{ {33B%5n"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _KAg1Ww  
nStartPos,nEndPos,i); HC>MCwx=r  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !"bU|a  
fileSplitterFetch.start(); ,A;wLI  
} XG8UdR|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fT0+inRG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +OfHa\Nz  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Fh~ pB>t  
nEndPos = " + nFileLength); `c'R42SA  
// fileSplitterFetch[nPos.length-1].start(); e6 a]XO^  
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//等待子线程结束 U IHe^?R  
//int count = 0; I0v4TjHH  
//是否结束while循环 UsnIx54D3  
boolean breakWhile = false; 0jM
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68nBc~iAm  
&m{vLw  
while(!bStop) 3<X*wVi)NN  
{ ^-dhz88wV  
write_nPos(); Km!~zG7<  
Utility.sleep(500); `+5,=S  
breakWhile = true; 7Lx=VX#]q  
\KkAU6  
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for(int i=0;i<nStartPos.length;i++) A?ij  
{ {:ZsUnzm  
if(!fileSplitterFetch.bDownOver) 3AcCa>
 
{ `l}+BI`4  
breakWhile = false; C
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break; z~\Y*\f^Y3  
} U{Moyj  
} C0[Z>$  
if(breakWhile) Oi,:
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break; >f-*D25f%  
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//count++; `Uy4>?  
//if(count>4) epQdj=h  
// siteStop(); VTs ,Ln!,U  
} {O (@}  
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System.err.println("文件下载结束！"); +=g9T`YbE  
} Rd>PE=u  
catch(Exception e){e.printStackTrace ();} :y3e-lr  
} A&7~]BR\  
qZ rv2dT  
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//获得文件长度 mH5[(?  
public long getFileSize() @Xl/<S&  
{ LRKl3"M  
int nFileLength = -1; "t:9jU  
try{ ]hjA,p@Q  
URL url = new URL(siteInfoBean.getSSiteURL()); %G/j+Pf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zjUT:#(k  
httpConnection.setRequestProperty("User-Agent","NetFox"); P= nu&$;  
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int responseCode=httpConnection.getResponseCode(); Ncsk~=[  
if(responseCode>=400) 'X/(M<c  
{ P"ATqQG%D  
processErrorCode(responseCode); [zc8f  
return -2; //-2 represent access is error uM74X^U  
} OVhtU+r  
+nm?+F  
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String sHeader; drW}w+!  
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for(int i=1;;i++) J>%uak<  
{ O cJ(i#Q~<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); hH*/[|z  
//Utility.log(in.readLine()); v5g]_v*F  
sHeader=httpConnection.getHeaderFieldKey(i); 5`Oaf\S  
if(sHeader!=null) 0="U'|J_  
{ /Lt Lu  
if(sHeader.equals("Content-Length")) ^rIe"Kx  
{ 6Cz%i6)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M?m)<vMr*  
break; BIeeu@p  
} HYWKx><  
} J'4V_Kjg-  
else |"o/GUI~  
break;  SED_^  
} ED=P 6u  
} |8s45g>  
catch(IOException e){e.printStackTrace ();} _{f7e^;  
catch(Exception e){e.printStackTrace ();} Q=T/hb  
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Utility.log(nFileLength); XX;MoE~MM  
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return nFileLength; JtGBNz!"  
} &<\i37y  
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'X{J~fEI!  
//保存下载信息（文件指针位置）  :bBMy\(u  
private void write_nPos() M@?,nzs K  
{ $S_G:}tna  
try{ \Czuf   
output = new DataOutputStream(new FileOutputStream(tmpFile)); cBz_L"5vr[  
output.writeInt(nStartPos.length); kjOPsz*0  
for(int i=0;i<nStartPos.length;i++) 3IHA+Zz  
{ |\iJ6m;a  
// output.writeLong(nPos); :3$-Qv X  
output.writeLong(fileSplitterFetch.nStartPos); D8,V'n>L  
output.writeLong(fileSplitterFetch.nEndPos); \CDzVO0^  
} [Adk
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output.close(); ,a1 1&"xl  
} `-QY<STTP9  
catch(IOException e){e.printStackTrace ();} dxAP7v  
catch(Exception e){e.printStackTrace ();} Weu%&u-  
} u{dI[?@  
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//读取保存的下载信息（文件指针位置） Al1BnFB  
private void read_nPos() 9Vh>ty1|_  
{ ,oS<9kC68  
try{ syR +;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); f1}am<  
int nCount = input.readInt(); dB%q`7O  
nStartPos = new long[nCount]; $yY\[C  
nEndPos = new long[nCount]; g9K7_T #W  
for(int i=0;i<nStartPos.length;i++) hfQx$cv6  
{ Se>"=[=  
nStartPos = input.readLong(); QYj8c]8f  
nEndPos = input.readLong(); c[RkiV3  
} ghu8Eg,Y  
input.close(); lX*IEAc  
} N5Rda2m  
catch(IOException e){e.printStackTrace ();} u^NZsuak  
catch(Exception e){e.printStackTrace ();} t3b64J[A{  
} XBF]|}%  
}'
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private void processErrorCode(int nErrorCode) U9ZWSDs  
{ 5oP31  
System.err.println("Error Code : " + nErrorCode); yS)73s/MrY  
} B]xZ 4Y  
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//停止文件下载
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public void siteStop() $<[Q8V-  
{ qek[p_7  
bStop = true; }%;o#!<N(@  
for(int i=0;i<nStartPos.length;i++) ;>z.wol  
fileSplitterFetch.splitterStop(); :"pA0oB  
+UGWTO\#ha  
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} !&k}YF  
} H(~:Ajj+zQ  
//负责部分文件的抓取 DnZkZ;E/  
**FileSplitterFetch.java )zR(e>VX  
*/ .P|_C.3-l  
package NetFox; Z"T#"FDIr  
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import java.io.*; Hlr[x  
import java.net.*; /2n-q_  
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public class FileSplitterFetch extends Thread { b85r=tm   
:&{:$-h!  
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String sURL; //File URL S{qc1qj  
long nStartPos; //File Snippet Start Position 8{t^< j$n  
long nEndPos; //File Snippet End Position R@+%~"Z  
int nThreadID; //Thread's ID ~q.a<B`,t  
boolean bDownOver = false; //Downing is over nF Mc'm  
boolean bStop = false; //Stop identical 0Q]ZS  
FileAccessI fileAccessI = null; //File Access interface Fbpe`pS+V  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +4N7 _Y  
{ 0I`)<o-  
this.sURL = sURL; 6dCS Gb  
this.nStartPos = nStart;
/*zngp@  
this.nEndPos = nEnd; gyz#:z$p^  
nThreadID = id; r}-si^fo;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w=ib@_:f  
} sUCI+)cM3  
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A*$JF>`7  
public void run() n7J6YtUwP  
{ f6I$d<  
while(nStartPos < nEndPos && !bStop) &$1ifG   
{ kXfTNM
b  
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try{ bc?\lD$$  
URL url = new URL(sURL); / bxu{|.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5a`f% h%  
httpConnection.setRequestProperty("User-Agent","NetFox"); mM[!g'*  
String sProperty = "bytes="+nStartPos+"-"; :"vW;$1 }  
httpConnection.setRequestProperty("RANGE",sProperty); r~q(m>Ct6  
Utility.log(sProperty); xzZ2?zWi  
,[} XK9  
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InputStream input = httpConnection.getInputStream(); _i/x4,=xv  
//logResponseHead(httpConnection); va`/Dp)M  
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byte[] b = new byte[1024]; V1P]mUs{1  
int nRead; vj_[LFE  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R2e":`0I  
{ cbton<r~  
nStartPos += fileAccessI.write(b,0,nRead); ]g3RVA%\l  
//if(nThreadID == 1) +nz6+{li\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <T3v|\6~H  
} dbE]&w`?d  
]T?Py)  
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Utility.log("Thread " + nThreadID + " is over!"); I1a>w=x!+  
bDownOver = true; '[Ue0r<jn  
//nPos = fileAccessI.write (b,0,nRead); dr[sSBTY"  
} 9GV1@'<Y]  
catch(Exception e){e.printStackTrace ();} m\0Xh*  
} _x2i=SFo*$  
} mw\ z'  
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=hP7Hea(N  
//打印回应的头信息 ~\{a<-R  
public void logResponseHead(HttpURLConnection con) B%.vEk)*  
{ R [[ #r5q  
for(int i=1;;i++) mr
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{ Z]QpH<Z  
String header=con.getHeaderFieldKey(i); t)i{=8rq  
if(header!=null) <27:O,I  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qdOUvf  
Utility.log(header+" : "+con.getHeaderField(header)); >iKbn  
else }MiEbLduN  
break; t++ a  
} u alpm#GU  
} _=\J:r|Y:  
vg"$&YX9"  
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public void splitterStop()
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{ v|7=IJ  
bStop = true; }#<mK3MBe  
} nj(\+l5  
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)&") J}@  
} -Gyj]v5y`c  
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/* Sc/\g  
**FileAccess.java D^30R*gV  
*//文件访问(定位，写) O u-/dE%  
package NetFox; yU{Q`6u T  
import java.io.*; <NYf!bx  
z|k0${iu#  
6/=0RTd  
public class FileAccessI implements Serializable{ b)(rlX  
d$gT,+|vu  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !!\x]
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RandomAccessFile oSavedFile; 8{f~tPY  
long nPos; Gm.sl},  
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public FileAccessI() throws IOException Tp[-,3L  
{ z#|tcHVFT  
this("",0); G &QGQ  
} /7CV7=^d,  
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public FileAccessI(String sName,long nPos) throws IOException Sp]u5\  
{ E|K|AdL  
oSavedFile = new RandomAccessFile(sName,"rw"); A0l-H/
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this.nPos = nPos; QUO'{;,  
oSavedFile.seek(nPos); Yf?hl  
} 51Q m2,P1^  
Q|7$SS6$  
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public synchronized int write(byte[] b,int nStart,int nLen) ]=Dzr<*v  
{ ?glK~G!i  
int n = -1; hR+\,P#G[  
try{ wV\.NQtS  
oSavedFile.write(b,nStart,nLen); U^&,xz$Cg  
n = nLen; k5@PZFV  
} h0oe'Xov  
catch(IOException e) !x$6wzKa  
{ MfU0*nVF~  
e.printStackTrace (); ]I[\Io1  
} H2JKQm_  
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return n; M->
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} L']"I^(N  
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} nXT/zfS  
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/* pdySip<  
**SiteInfoBean.java tu:W1?  
*/ 'D:R]@eK]  
package NetFox; $V\Dl]a1  
UGDB4S  
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public class SiteInfoBean { WI6h G  
X8\UTHT&0  
!I jU*c@  
private String sSiteURL; //Site's URL Qv}TUX4  
private String sFilePath; //Saved File's Path fda)t1u\8  
private String sFileName; //Saved File's Name 1'YUK"i  
private int nSplitter; //Count of Splited Downloading File =1+/`w  
X-y3CO:&@h  
c\le8C3  
public SiteInfoBean() HJ+Q7)  
{//nSplitter的缺省值为5 v83@J~  
//default value of nSplitter is 5  Eyq4w  
this("","","",5); ~$jRn(2  
} V.-cm51I  
:Xs3Vh,V  
w'6sJ#ba(  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >K!$@]2F  
{ T$"sw7<  
sSiteURL= sURL; d<cqY<y VA  
sFilePath = sPath; tNG[|Bi#  
sFileName = sName; BIXbdo5F  
this.nSplitter = nSpiltter; O<P(
UT"  
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Y3JIDT^  
}  :!/ (N  
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public String getSSiteURL() 8gxo{<,9  
{ |)y-EBZe\"  
return sSiteURL; KP)t,\@f!  
} %z6_,|%  
mEg3.|  
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public void setSSiteURL(String value) jct'B}@X(  
{ J-z<&9  
sSiteURL = value; 6>gm!6`  
} Q%:Z&lgy  
- VdCj%r>  
AfpC >>=@  
public String getSFilePath() NXMZTZpB7  
{ O$7
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return sFilePath; >zfFvx_q  
} 3/ '5#$  
.sSbU^U  
jbe_r<{  
public void setSFilePath(String value) ,B#*<_?E5  
{ [D"5@  
sFilePath = value; +y^'\KN  
} /5X_gjOL,  
ct
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public String getSFileName() #sE:xIR  
{ #y f  
return sFileName; &ZL4/e  
} G2&,R{L6w  
}yaM.+8.  
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public void setSFileName(String value)
30YH}b#B  
{ K!
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sFileName = value; pf&U$oR4  
} N%S|Ey@f  
8~sC$sIlE  
p_i',5H(  
public int getNSplitter() =&^tfD  
{ 7AF6aog  
return nSplitter; =@D H hg  
} 7- |N&u  
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kP1cwmZ7F  
public void setNSplitter(int nCount) a4mRu|x  
{ q ,+29  
nSplitter = nCount; ; o(:}d  
} Y?- "HK:  
} uANpqT}!  
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/* n72kJ3u.  
**Utility.java &79F Uac  
*/ >DAi
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package NetFox; ]GDjR'[z  
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{I/t3.R`  
public class Utility { "jf_xZ$H-
 
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public Utility() 2Vs+8/  
{ ,u9>c*Ss\  
})j N 8px  
@ V_i%=go  
} |d,bo/:  
!DD4Bqez  
//线程睡眠 lQv(5hIm  
public static void sleep(int nSecond) }@~+%_;  
{ B%5"B} nG  
try{ o*3\xg  
Thread.sleep(nSecond); 8@ f+?g*i  
} ^\r{72!y  
catch(Exception e) ikO9p|J
 
{ @k\,XV`T~t  
e.printStackTrace (); wRZS+^hx  
} 'wWuR@e#&  
} hxt;sQAo{  
q3`~uTzk  
//日志 q.j
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public static void log(String sMsg) C=bQ2t=Z  
{ %r&36d'  
System.err.println(sMsg); 39d$B'"<1  
} 6n;? :./  
4%4Yqx )  
4y!GFhMh  
public static void log(int sMsg) rxj#  
{ `XM0Mm%  
System.err.println(sMsg); cYBjsN(!A|  
} wYDdy gS  
} Lt i2KY}/%  
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/* !%B-y9\  
**TestMethod.java oi8M6l  
*/ ge1U1o  
package NetFox; (h
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AmQsay#I_  
P<;Puww/  
public class TestMethod { .HRd6O;  
iBmvy7S?  
8"A0@fNz  
public TestMethod() +11oVW  
{ ///xx/weblogic60b2_win.exe KUC%Da3  
try{ "rVM23@ tq  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); wL}X~Xa3i  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~qXwQ@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); qE8Di\?  
fileFetch.start(); $ab{GxmX'4  
} SjIDzNI5  
catch(Exception e){e.printStackTrace ();} z2Z}mktP  
.EvP%A m  
B1]FB|0's  
} =1xVw5^F  
_Fe=:q  
Qz"//=hC|H  
public static void main(String[] args) 0#ON}l)>  
{ J(A+mYr{:  
new TestMethod(); KFy|,@NI  
} 5kADvi.  
} 5DO}&%.xt  
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