http断点续传简单实现（java)

/* ,yPs4',d  
**SiteFileFetch.java ct o+W}k  
*/ -o: ifF|  
package NetFox; 'OEh'\d+x  
import java.io.*; itotn!Wb`  
import java.net.*; 3jR>  
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public class SiteFileFetch extends Thread { pX 4:WV  
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SiteInfoBean siteInfoBean = null; //文件信息Bean U-h'a: K  
long[] nStartPos; //开始位置 Ebk9[=  
long[] nEndPos; //结束位置 KkD.n#A  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^lw0} i  
long nFileLength; //文件长度 3jeB\  
boolean bFirst = true; //是否第一次取文件 ]\TYVv)  
boolean bStop = false; //停止标志 KH=4A-e,0  
File tmpFile; //文件下载的临时信息 hKx*V"7/#\  
DataOutputStream output; //输出到文件的输出流 PeU>h2t  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） *;N6S~_'Y  
public SiteFileFetch(SiteInfoBean bean) throws IOException '>"
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{ mHj3ItXUu  
siteInfoBean = bean; 3$ 'eDa[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <xn96|$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8,VX%CS#q  
if(tmpFile.exists ()) xJcM1>cT>  
{ yiT)m]E d  
bFirst = false; TK! D=M  
read_nPos(); 5Yxs_t4  
}
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else 85{2TXQ^%=  
{ Nd;)V  
nStartPos = new long[bean.getNSplitter()]; lhk=yVG3  
nEndPos = new long[bean.getNSplitter()]; Ire+r "am  
} xbTvv>'U  
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} EdH;P\c  
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public void run() [<0\v<{`L  
{ \N|ma P  
//获得文件长度 #.j[iN :+  
//分割文件 '!V5 #J  
//实例FileSplitterFetch (7zdbJX  
//启动FileSplitterFetch线程 K-<kp!v  
//等待子线程返回 1J{1>r  
try{ ?^X e^1(  
if(bFirst)  UZ*
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{ *m>XtBw.  
nFileLength = getFileSize(); jIvSjlmI  
if(nFileLength == -1) M= ]]kJ:I  
{ M"W~%   
System.err.println("File Length is not known!"); $E >)  
} u*h+c8|zI  
else if(nFileLength == -2) {e/6iSpT  
{ \>7hT;Av=G  
System.err.println("File is not access!"); hRc.^"q9  
} Y-ZTv(<  
else Sd9%tO9mf  
{ (>)f#t[9J  
for(int i=0;i<nStartPos.length;i++) 7^hwRZJ{  
{ ~#]$YoQ&O  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %C1*`"Jb&  
} .dE2,9{Z  
for(int i=0;i<nEndPos.length-1;i++) <T^:`p/]4  
{ I\y=uC  
nEndPos = nStartPos[i+1]; }Ghh%]  
} .[Hv/?L  
nEndPos[nEndPos.length-1] = nFileLength; H)@f_pfj(  
} qX_( M2oLU  
} <H]1 6  
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#P,C9OQD  
//启动子线程 rn8#nQ>QZ%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; sI,S(VWor  
for(int i=0;i<nStartPos.length;i++) ;,&$ob*/  
{ cD5^mxd%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |to|kU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I_aSC4  
nStartPos,nEndPos,i); gX'nFGqud  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \v,mr|  
fileSplitterFetch.start(); %=PGvu  
} f8AgTw,K8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T+knd'2V6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [BLBxSL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]+)cXJ}6#  
nEndPos = " + nFileLength); .I1k+   
// fileSplitterFetch[nPos.length-1].start(); z>&|:VGG  
uK!G-1   
 y5!fbmf  
//等待子线程结束 m|8lj
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//int count = 0; L2WH-
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//是否结束while循环 9{(A-  
boolean breakWhile = false; DtRu&>o_6D  
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while(!bStop) FHv^^
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{ iH;IXv,b3  
write_nPos(); =)O%5<Lwx  
Utility.sleep(500); Y5&mJp\G  
breakWhile = true; o)U4RY*  
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for(int i=0;i<nStartPos.length;i++) /l.ox.4z#  
{ &}+^*X  
if(!fileSplitterFetch.bDownOver) caC-JcDXy  
{ q"OJF'>w5  
breakWhile = false; }iBFo\vU  
break; #CcC& I :c  
} a*T=;P3(I  
} b$,~S\\c  
if(breakWhile) >`S $(f  
break; #y2IHO-  
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//count++; ^:Hx.  
//if(count>4) Yg<4}l."  
// siteStop(); mAZfo53  
} &40# _>W7  
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#|ILeby  
System.err.println("文件下载结束！"); .kT}E5  
} K4`)srd  
catch(Exception e){e.printStackTrace ();} nS$_VJ]~  
} OdWZYWj  
{OBV+}#  
']'V?@H]4  
//获得文件长度 $T-Pl57  
public long getFileSize() 6.(
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{ 4IUdlb  
int nFileLength = -1; %+F%C=GqI  
try{ Yfa`}
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URL url = new URL(siteInfoBean.getSSiteURL()); +yO^,{8SE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M&q3xo"w  
httpConnection.setRequestProperty("User-Agent","NetFox"); W81dLeTZg  
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int responseCode=httpConnection.getResponseCode(); xJemc3]2  
if(responseCode>=400) O3];1ud  
{
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processErrorCode(responseCode); #eZm)KFQg  
return -2; //-2 represent access is error [i 7^a/e  
} {%! >0@7  
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 |tVWmm^m  
String sHeader; *F)+- BB  
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for(int i=1;;i++) vk>EFm8l  
{ =j&qat  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !8ch&cr)o+  
//Utility.log(in.readLine()); /jB0  
sHeader=httpConnection.getHeaderFieldKey(i); >r8$vQGj  
if(sHeader!=null) -]$=.0 l  
{ S9@2-Oc  
if(sHeader.equals("Content-Length")) 6vL+qOdx  
{ CG397Y^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <^v-y)%N:A  
break; Hp}dm93T  
} NBaXfWh  
} +61h!/<W  
else x4 .Y&Wq#  
break; G0^,@jF?b  
} -s5>GwZt  
} 2"IsNbWV  
catch(IOException e){e.printStackTrace ();} ~V`F5B  
catch(Exception e){e.printStackTrace ();} E2%{?o  
27CVAX ghV  
89
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Utility.log(nFileLength); \'[C_+;X  
5<=ktA48[  
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return nFileLength; L4)  
} 1nAAs;`'  
23_\UTM}1  
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//保存下载信息（文件指针位置）  FKpyD  
private void write_nPos() vOnhJN  
{ *v6 j7<H  
try{ r@v_hc  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?$Tp|<tx#  
output.writeInt(nStartPos.length); 0n
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for(int i=0;i<nStartPos.length;i++) _4lhwKYU  
{ {DVu* %|  
// output.writeLong(nPos); H7&bUt/  
output.writeLong(fileSplitterFetch.nStartPos); wz1fl#WU  
output.writeLong(fileSplitterFetch.nEndPos); ^\Gukkmh}  
} (w
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output.close(); Z7:TPY$b  
} Sn~h[s_(  
catch(IOException e){e.printStackTrace ();} sY*iR
q  
catch(Exception e){e.printStackTrace ();} ]Ac&h aAP  
} Pi&8!e<  
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//读取保存的下载信息（文件指针位置） =,WW#tD  
private void read_nPos() ?jy6%Y#,i  
{ F?EAIL  
try{ uL1$yf'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ![}q9aeT  
int nCount = input.readInt(); }_GI%+t  
nStartPos = new long[nCount]; < X&{6xu  
nEndPos = new long[nCount]; s?-J`k~q  
for(int i=0;i<nStartPos.length;i++) 25m6/Y  
{ ,{rm<M.)  
nStartPos = input.readLong(); B$)&;Q  
nEndPos = input.readLong(); BH+@!H3hf  
} d4[mR~XXT  
input.close(); qQ=\R1l  
} +\@}IKWl-?  
catch(IOException e){e.printStackTrace ();} w]Byl3}Gt  
catch(Exception e){e.printStackTrace ();} U)B^R  
} a-(OAzQ_  
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private void processErrorCode(int nErrorCode) <-avC/M$d  
{ h|OsT  
System.err.println("Error Code : " + nErrorCode); v5Qp[O_  
} WK)2/$7
@  
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//停止文件下载 ,MRAEa2  
public void siteStop() 4,.B#: 8  
{ i{.%4tA4  
bStop = true; nPh|rW=  
for(int i=0;i<nStartPos.length;i++) ER4j=O#  
fileSplitterFetch.splitterStop(); $<QOMfY>  
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} hantGw|  
} "PhP1;A9,  
//负责部分文件的抓取 xfsf  
**FileSplitterFetch.java kH9P(`;Vq  
*/ 64jFbbd-/  
package NetFox; O>)Fl42IeD  
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import java.io.*; d>OLnG> F  
import java.net.*; `L#`WC@[o  
/Q*o6Gys0  
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public class FileSplitterFetch extends Thread { F-SD4a  
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+#Q\;;FNP  
String sURL; //File URL X6`F<H`
 
long nStartPos; //File Snippet Start Position &Bfgvws;  
long nEndPos; //File Snippet End Position l*(Ml= O{  
int nThreadID; //Thread's ID .W/#$s|X\  
boolean bDownOver = false; //Downing is over N# ?}r>W3  
boolean bStop = false; //Stop identical $ &III  
FileAccessI fileAccessI = null; //File Access interface 7%g8&d  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /yhGc}h  
{ Jq8CII  
this.sURL = sURL; $MPh\T  
this.nStartPos = nStart; 5:r*em  
this.nEndPos = nEnd; A\IQM^i  
nThreadID = id; g$P<`.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <!m'xOD  
} %40uw3  
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public void run() F )|0U~  
{ P_{jZ}y(  
while(nStartPos < nEndPos && !bStop) B<}0r4T}  
{ ,KO_h{mI<  
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try{ vSf ?o\O  
URL url = new URL(sURL); fVJsVZ"6v`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zVL"$ )  
httpConnection.setRequestProperty("User-Agent","NetFox"); `Fn6*_n  
String sProperty = "bytes="+nStartPos+"-"; #Y9'n0 AL  
httpConnection.setRequestProperty("RANGE",sProperty); '1u!@=.\G  
Utility.log(sProperty); ZA>p~Zt  
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InputStream input = httpConnection.getInputStream(); #;*0 Pwe`  
//logResponseHead(httpConnection); U0Q:sA U  
: U:>X6f  
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byte[] b = new byte[1024]; xP+HdA2X  
int nRead; |4lrVYG^K  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "B9aJo  
{ l{u2W$8  
nStartPos += fileAccessI.write(b,0,nRead); 3\~ RWoB0u  
//if(nThreadID == 1) bU+ z(Eg6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1_Ag:>#X  
} U!xOJ  
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.  
Utility.log("Thread " + nThreadID + " is over!"); E?@batIrf  
bDownOver = true; RXZ}aX[h  
//nPos = fileAccessI.write (b,0,nRead); wy)I6`v  
} ?oKY"C8/  
catch(Exception e){e.printStackTrace ();} P*M$^p
  
} nm3/-Q},  
} Q \E[py  
:j=/>d],%  
/`)>W :  
//打印回应的头信息 'i5V6yB  
public void logResponseHead(HttpURLConnection con) @jvF[wi;  
{ !~Am1\02  
for(int i=1;;i++) `tZ-8f  
{ _t+.I9kQ  
String header=con.getHeaderFieldKey(i); h4\j=Np  
if(header!=null) O F|3y~z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); =5PNH2  
Utility.log(header+" : "+con.getHeaderField(header)); L(Ffa(i  
else k%[pZ5.!  
break; WOgPhJ  
} 7G^`'oZ  
} 2:>|zmh_  
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public void splitterStop() 5qx,b&^w  
{ K.{:H4_  
bStop = true; Z\@m_/g  
} 4Em$L]7  
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} "N|gU;~W  
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/* $u`v k|\R  
**FileAccess.java R"0fZENTG  
*//文件访问(定位，写) 9*"Ae0ok1  
package NetFox; .S{Q }S  
import java.io.*; #UO#kC<2(B  
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zURob MpE#  
public class FileAccessI implements Serializable{ 6)QJms  
|KM<\v(A{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p?q~.YY  
RandomAccessFile oSavedFile; R>05MhA+  
long nPos; qit D{;  
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public FileAccessI() throws IOException AZi|85rN  
{ ,2I8,MOg  
this("",0); c,\!<4  
} 8LH"j(H  
:())%Xu3  
9w%|Nk>=>  
public FileAccessI(String sName,long nPos) throws IOException X9d~r_2&m<  
{ /61P`1y(J  
oSavedFile = new RandomAccessFile(sName,"rw"); f"8!uE*;  
this.nPos = nPos; JDIQpO"Qji  
oSavedFile.seek(nPos); cc"L> XoK  
} J#pl7q)^w  
"gR W91 T  
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public synchronized int write(byte[] b,int nStart,int nLen) w=r3QKm#K  
{ )kq3q5*_  
int n = -1; )7H s  
try{ U!0 Qf7D  
oSavedFile.write(b,nStart,nLen); g7-=kmr|V  
n = nLen; %Q0J$eC  
} Bx>)i8P7i0  
catch(IOException e) yLo{^4a.  
{ ##6_kcL:6G  
e.printStackTrace (); X)tf3M {J@  
} \U1fUrw$*  
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@  
return n; )AX0x1I|E  
} 6"d^4L?  
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} ]lKQwpX3  
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/* GCf3'u  
**SiteInfoBean.java t:|+U:! >  
*/ o9l =Q  
package NetFox; !+E|{Zj  
~}c`r4  
LOD'iiH6  
public class SiteInfoBean { e@-"B9~   
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?Q~6\xA  
private String sSiteURL; //Site's URL Pmj]"7Vd[  
private String sFilePath; //Saved File's Path Mbt}G|;8H7  
private String sFileName; //Saved File's Name I1H} 5bf3  
private int nSplitter; //Count of Splited Downloading File >UP{=`  
X>n\@rTo  
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public SiteInfoBean() Whf7J'  
{//nSplitter的缺省值为5 GS%i<HQ3  
//default value of nSplitter is 5 &*I\~;1  
this("","","",5); suh@  
} jf&LSK
;2  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )-_NtMr~`!  
{ :y?xS  
sSiteURL= sURL; iaqhP7!  
sFilePath = sPath; \L
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sFileName = sName; FN#6pM']|  
this.nSplitter = nSpiltter; x4PH-f-7  
n\nC.|_G@  
"%c\i-&t  
} %f{1u5+5  
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public String getSSiteURL() H$^b.5K  
{ 9I a4PPEH1  
return sSiteURL; +TzF*N
p  
} |P_\l,f8`  
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public void setSSiteURL(String value) C-
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{ t|gEMDGa3  
sSiteURL = value; O1@-)<_71  
} KfU4#2}
 
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public String getSFilePath() %$b)l?!  
{ "t<${  
return sFilePath; uC3o@qGW<  
}  [69[
Ct  
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;&2J9  
public void setSFilePath(String value) G`9\v
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{ >IW0YIQy,  
sFilePath = value; f\Bd lOJ>  
} AsRS7V  
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public String getSFileName() m6aq_u{W  
{ +\FTR  
return sFileName; la ~T)U7  
} U!:Q|':=h  
?_e2)+q8YG  
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public void setSFileName(String value) O a_2J#~$  
{ >EFjyhVE  
sFileName = value; /r#.BXP  
} %]JSDb=C  
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Epm\=s  
public int getNSplitter() 3~"G(UP  
{ $_-f}E  
return nSplitter; G9s: Wp  
} +OFq=M  
UV%Al)3  
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public void setNSplitter(int nCount) ;d1\2H  
{ D6,rb 9  
nSplitter = nCount; 7|6uY  
} !>B|z=  
} 1F*gPhm  
}&d@6m]  
_ x&Y'X|  
/* 8(UUc>g  
**Utility.java R07K
ure  
*/ w/r wE  
package NetFox; '>AOJaA  
|3f?1:"Z  
\*x]xc/^  
public class Utility { eK\1cs  
[HB>\   
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public Utility() xzg81sV7  
{ @U6Iw"@  
.OM m"RtK  
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} 5V&3m@d0aq  
*TY?*H  
//线程睡眠
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public static void sleep(int nSecond) T:aYv;#0  
{ c&.>SR')  
try{ V`Z-m-V~1  
Thread.sleep(nSecond); Hu|;cbK  
} ahNpHTPa  
catch(Exception e) Ml1sE,B
T  
{ <rc?EV  
e.printStackTrace (); 5v4 ,YHD  
} 42aYM!  
} K_ P08  
T]\_[e:'  
//日志 K1M
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public static void log(String sMsg) WpE\N0Yg  
{ (J8(_MF  
System.err.println(sMsg); 7A|n*'[T>  
} PSz|I8 c  
/t`s.!k  
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public static void log(int sMsg) l
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{ MXsSF|-  
System.err.println(sMsg); N;ed_!  
} b f.__3{  
} 5LU8QHj3  
d^sS{m\  
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/* bD[W`yW0  
**TestMethod.java )IQa]A  
*/ A{mv[x-XN  
package NetFox; [V_Z9-f*  
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public class TestMethod { 
\
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s(W]>Ib  
'+LbFGrO3  
public TestMethod() ?4Z`^uy  
{ ///xx/weblogic60b2_win.exe Jylav:  
try{ coq7La[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); n}cjVH5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
|T<t19  
SiteFileFetch fileFetch = new SiteFileFetch(bean); XnmQp)nyV  
fileFetch.start(); m[6?v;w  
} Q@gmtAp  
catch(Exception e){e.printStackTrace ();} 3B#qQ#  
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} pEf1[ z
q  
vZ[wr@)  
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public static void main(String[] args) aI]
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{ {\3ZmF  
new TestMethod(); bK:mt`  
} 7}>7@W8  
} x"q!=&>f  
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