http断点续传简单实现（java)

/* J-v1"7[2GC  
**SiteFileFetch.java @Vre)OrN#  
*/ b6N[t _,  
package NetFox; {%R^8  
import java.io.*; {o}U"b<+Ra  
import java.net.*; I=y7$+7%  
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public class SiteFileFetch extends Thread { (~GQncqa  
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SiteInfoBean siteInfoBean = null; //文件信息Bean g+ c*VmY  
long[] nStartPos; //开始位置 vI{aF- #  
long[] nEndPos; //结束位置 xb,XI/
 
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6 c
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long nFileLength; //文件长度 3uLG$`N   
boolean bFirst = true; //是否第一次取文件 TN(Vzs%  
boolean bStop = false; //停止标志 DB/~Z  
File tmpFile; //文件下载的临时信息 oac)na:O#  
DataOutputStream output; //输出到文件的输出流 YOl$sgg}  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .-d'*$ yJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException vK',!1]y  
{ ~:ASv>m  
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5h5izA'0'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); XF!L.'zH  
if(tmpFile.exists ()) Z`Y&cKsn  
{ #e'>9T  
bFirst = false; K:,V>DL  
read_nPos(); ?I}RX~Tgg  
} G4* LO  
else p*;!5;OUR  
{ K10G+'H^  
nStartPos = new long[bean.getNSplitter()]; [wGj?M}  
nEndPos = new long[bean.getNSplitter()]; -DI >O/  
} s L^+$Mq6  
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} L&pR#  
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public void run() 19E(Hsz  
{ /K:r4Kw  
//获得文件长度 OoB|Eh|),  
//分割文件 q$:1Xkl  
//实例FileSplitterFetch s<I
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HC  
//启动FileSplitterFetch线程 PLCm\Oh$l  
//等待子线程返回 CTIS}_CWd=  
try{ LV:L0D7y  
if(bFirst) q0.!T0i  
{ w1/QnV  
nFileLength = getFileSize(); tOIqX0dWd  
if(nFileLength == -1) Qit&cnO
 
{ _.5{vGyxr  
System.err.println("File Length is not known!"); 7^gO>2~  
} G6G Bqp6|  
else if(nFileLength == -2) ^ja]e%w#  
{ [\8rh^LFi  
System.err.println("File is not access!"); UqK.b}s  
}
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else S\GWMB!oF  
{ 20c5U%  
for(int i=0;i<nStartPos.length;i++) @%4'2b  
{ Mu3G/|t(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4Mt3<W5  
} f_~T  
for(int i=0;i<nEndPos.length-1;i++) 7-744wV}Z  
{ (0{Dn5MH  
nEndPos = nStartPos[i+1]; T?8BAxC?K  
} j7}mh  
nEndPos[nEndPos.length-1] = nFileLength; iOiFkka  
} 6#z8 %kaX  
} SU0SsgFB  
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//启动子线程 <"3q5ic/Z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; q{w|`vIb  
for(int i=0;i<nStartPos.length;i++) %]P{)*y-?  
{ fFJ7Y+^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "6U0 !.ro@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), fG\"p  
nStartPos,nEndPos,i); Cy-p1s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);
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fileSplitterFetch.start(); [ja^Bhu  
} PzJ(Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 64'2ICf#m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); u62H+'k}F  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ffP]U4  
nEndPos = " + nFileLength); \(Ma>E4PNU  
// fileSplitterFetch[nPos.length-1].start(); j/t%7,  
Uh/=HNR  
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//等待子线程结束 Kbu>U{'  
//int count = 0; 8F[];LF>  
//是否结束while循环 ]!ai?z%cK#  
boolean breakWhile = false; -6)nQNj|  
(wu'FFJp#  
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while(!bStop) d9[j4q_  
{ q^xG%YdPz+  
write_nPos(); ! $JX3mP  
Utility.sleep(500); JSUD$|RiJ  
breakWhile = true; Ou
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0MRWx%CR  
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for(int i=0;i<nStartPos.length;i++) M6wH$!zRa  
{ 5WI bnV@  
if(!fileSplitterFetch.bDownOver) +.Vh<:?
 
{ 2)IM<rf'^  
breakWhile = false; >_j(uw?u  
break; b_sasZo  
} G$,s.MSf  
} K~#?Y,}O  
if(breakWhile) l2;$qNAo  
break; M"*NV(".g  
dEYw_qJ2  
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//count++; ;MeY@*"{  
//if(count>4) z#gebr~_\  
// siteStop(); 
#~p;s>  
} r(Sh  
>r`O@`^U  
'=nmdqP  
System.err.println("文件下载结束！"); 'A|c\sy  
} ou0TKE9 _  
catch(Exception e){e.printStackTrace ();} +788aK,{#  
} G+#bO5  
&&CrF~  
@(L}:]{@  
//获得文件长度 ft7M9<#v  
public long getFileSize() 50 w
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{ ItLR|LO9  
int nFileLength = -1;  0Y!"3bw|  
try{ Pfs_tu  
URL url = new URL(siteInfoBean.getSSiteURL()); OybmyGHY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `IlhLv  
httpConnection.setRequestProperty("User-Agent","NetFox"); >3&  
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int responseCode=httpConnection.getResponseCode(); UG44 oKB  
if(responseCode>=400) <Z t]V`-  
{ psvc,V_*  
processErrorCode(responseCode); g@x72$j  
return -2; //-2 represent access is error L+ew/I>:  
} Z:^<NdKe  
1/1oT  
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String sHeader; +s
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for(int i=1;;i++) 1/\Xngd  
{ >"UXY)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); EO(l?Fgw]$  
//Utility.log(in.readLine()); el<Gd.p.d  
sHeader=httpConnection.getHeaderFieldKey(i); hQ>$"0K  
if(sHeader!=null) tYMr  
{ O.#Rr/+)  
if(sHeader.equals("Content-Length")) |Zn;O6c#L5  
{ )/f#~$ws  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &:C[ nq  
break; iuqJPW^}  
} Tq*<J~-  
} Dd0yQgCu  
else pHk$_t  
break; \8*j"@ !H  
} fWJOP sp*/  
} -mO<(wfV>  
catch(IOException e){e.printStackTrace ();} ?r]0%W^  
catch(Exception e){e.printStackTrace ();} aiX4;'$x!  
{|%^'lS  
}x{1{Bw>Y  
Utility.log(nFileLength); i`6utOq  
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return nFileLength; =|O]X|y-lZ  
} [$$R>ELYQ  
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//保存下载信息（文件指针位置） }|-8-;  
private void write_nPos() ,: z]15fX  
{ U3aM^
 
try{ 1mh7fZgn  
output = new DataOutputStream(new FileOutputStream(tmpFile)); C<QpUJ`k  
output.writeInt(nStartPos.length); ?=?*W7  
for(int i=0;i<nStartPos.length;i++) bA6^RIf?  
{ 3?gfDJfE  
// output.writeLong(nPos); hYFi
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output.writeLong(fileSplitterFetch.nStartPos); Z5wDf+
 
output.writeLong(fileSplitterFetch.nEndPos); )abH//Pps.  
} j$u  
output.close(); Rc@lGq9  
} SRHD"r^@  
catch(IOException e){e.printStackTrace ();} 1_xkGc-z<  
catch(Exception e){e.printStackTrace ();} ndBqXS  
} KB\ri&bF  
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//读取保存的下载信息（文件指针位置） I?q- :9
:  
private void read_nPos() 8;UkZN"hy5  
{ 8SiWAOQAL  
try{ /K,@{__JP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -
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int nCount = input.readInt(); *|+$7j  
nStartPos = new long[nCount]; M.$=tuUL  
nEndPos = new long[nCount]; *xeJ4h  
for(int i=0;i<nStartPos.length;i++) `]&'yt  
{ 4&L,QSJ V  
nStartPos = input.readLong(); B(wi+;  
nEndPos = input.readLong(); 2fm6G).m  
} 2C_I3S~U  
input.close(); A,#z_2~  
} #Guwbg  
catch(IOException e){e.printStackTrace ();} {v3@g[:|  
catch(Exception e){e.printStackTrace ();} I=E\=UTG,5  
} b3=XWzK5  
{!4ZRNy(k  

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private void processErrorCode(int nErrorCode) "LZv\c~v,%  
{ p|r>tBv?x  
System.err.println("Error Code : " + nErrorCode); }V+&o\4  
} 4tt=u]:  
]#rmk!VT?  
;UQ&yj%x  
//停止文件下载 ;[,#VtD  
public void siteStop() M%eTNsbNm  
{ 0M}Ql5+h,  
bStop = true; XOZ@ek)LY  
for(int i=0;i<nStartPos.length;i++) i,y{*xBT  
fileSplitterFetch.splitterStop(); w 3L+7V,!  
^X*l&R_=R  
,v*\2oG3^  
} cc3+Wx_  
} gqAN-b'  
//负责部分文件的抓取 m?)F@4]  
**FileSplitterFetch.java PiX(Ase  
*/ T,4REbm^  
package NetFox; VB+y9$Y'  
j+3=&PkA.]  
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import java.io.*; L<N=,~  
import java.net.*; qS[nf>"  
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public class FileSplitterFetch extends Thread { =NL(L  
M0MvOO*ad  
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String sURL; //File URL _ Av_jw`m  
long nStartPos; //File Snippet Start Position ~,84E [VV  
long nEndPos; //File Snippet End Position *2I@_b6&  
int nThreadID; //Thread's ID w5Yt mnP  
boolean bDownOver = false; //Downing is over v
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boolean bStop = false; //Stop identical KQrG|<J  
FileAccessI fileAccessI = null; //File Access interface `c_Wk]i  
NFb<fD[C  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nA#dXckoc  
{ $C&E3 'O  
this.sURL = sURL; sMWNzt  
this.nStartPos = nStart; )m(?U
 
this.nEndPos = nEnd; i}LVBx"K(  
nThreadID = id; 7brC@+ZD  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ne2eBmY}(  
} a"X9cU[  
ywbdV-t/  
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public void run() HY7#z2L  
{ *Ag,/Cm]  
while(nStartPos < nEndPos && !bStop) agPTY{;  
{ V3>JZH`  
'u4TI=[6  
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try{ _B^Q;54c  
URL url = new URL(sURL); 6n$g73u<=3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &^^V*O  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'C<4{agS  
String sProperty = "bytes="+nStartPos+"-"; xU;;@9X  
httpConnection.setRequestProperty("RANGE",sProperty); >Y"Ru#Ju9  
Utility.log(sProperty); 96S#Q*6+R  

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InputStream input = httpConnection.getInputStream(); /}$D&KwYg  
//logResponseHead(httpConnection); W(,3j{d2i  
h_K!ch}  
% (x9~"  
byte[] b = new byte[1024]; phqmr5s^H  
int nRead; #hF(`oX}4K  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tsN,yI]-VA  
{ X_2pC|C  
nStartPos += fileAccessI.write(b,0,nRead); pt=H?{06  
//if(nThreadID == 1) [^2c9K^NK  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6ly`lu9  
} >K-S&Y  
fy|$A@f  
@pO2A6Ks  
Utility.log("Thread " + nThreadID + " is over!"); .h[yw$z6  
bDownOver = true; S!+}\*  
//nPos = fileAccessI.write (b,0,nRead); Dt=@OZW  
} .*Ylj2nM  
catch(Exception e){e.printStackTrace ();} 9B?-&t  
} }GL@?kAGR5  
} &*8_w-  
h0)Dj(C  

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//打印回应的头信息 &Na,D7A:3I  
public void logResponseHead(HttpURLConnection con) TNkvdE-S  
{ )4e?-?bK!  
for(int i=1;;i++) .6[7D  
{ `A ^  
String header=con.getHeaderFieldKey(i); = 4 wf  
if(header!=null) dh S7}n  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); bfXyuv  
Utility.log(header+" : "+con.getHeaderField(header)); Z]qbLxJV  
else @p ZjJ<9QM  
break; sFV&e->AN\  
} 7oV$TAAf  
} ;9$71E  
" `FcW  
VMIX=gTZ  
public void splitterStop() V;29ieE!
 
{ VDTt}J8  
bStop = true; +^|_vq^XR  
} Lz{z~xNHW.  

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RG_.0'5=hc  
} D0^h;wJ=4+  
g+A>Bl3#  
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/* )k.}>0K |  
**FileAccess.java h?'~/@  
*//文件访问(定位，写) `3:Q.A_?  
package NetFox; oju,2kpH7#  
import java.io.*; -}(2}~{e(  
Kv9Z.DY  
1]69S(  
public class FileAccessI implements Serializable{ rXP~k]tC  
&EmG\vfE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 zf;sdQ;4  
RandomAccessFile oSavedFile;  stQ_Ke  
long nPos; C),i#v  
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public FileAccessI() throws IOException Q[{RNab  
{ f@[qS7ok  
this("",0); 6EeO\Qj{  
} P; h8  
F?^L^N^  
aW-6$=W  
public FileAccessI(String sName,long nPos) throws IOException F3hG8YX  
{ #%EHcgF  
oSavedFile = new RandomAccessFile(sName,"rw"); z]7/Gc,j  
this.nPos = nPos; $,P:B%]  
oSavedFile.seek(nPos); kH8/
8  
} .,20_<j%=  
"}V_.I*+  
DD2K>1A1  
public synchronized int write(byte[] b,int nStart,int nLen) .5uqc.i"f  
{ "([/G?QAG  
int n = -1; stUUez>  
try{ L0oVXmlr  
oSavedFile.write(b,nStart,nLen); AmC?qoEWQ7  
n = nLen; T+^c=[W  
} h aApw(.%  
catch(IOException e) wZs 2aa  
{ AJm$(3?/D  
e.printStackTrace (); ^=5x1<a9$  
} =3 Vug2*wd  
"Kdn`zN{  
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return n; -Caj>K  
} BlQX$s]  
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} |R1T;J<[  
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/* 3H`{ A/r  
**SiteInfoBean.java a{
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*/ [orL.D]  
package NetFox; a eeo
r  
3ye  
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public class SiteInfoBean {
1"L"LU'  
!3Pbu=(cte  
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private String sSiteURL; //Site's URL ,T`,OZm  
private String sFilePath; //Saved File's Path t:5-Ro  
private String sFileName; //Saved File's Name EG;E !0  
private int nSplitter; //Count of Splited Downloading File c~?Zmdn:  
KVJ, a  
m
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public SiteInfoBean() bD{k=jum  
{//nSplitter的缺省值为5 Ff%V1BH[  
//default value of nSplitter is 5 !7 dct#4  
this("","","",5); ?UZt30|1  
} "GZieI D  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #5Z`Q^  
{ acR|X@\3  
sSiteURL= sURL;
6e
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sFilePath = sPath; R2gV(L(!!  
sFileName = sName; ylKK!vRHT  
this.nSplitter = nSpiltter; ^A
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0{|HRiQH9+  
sfj+-se(K.  
} 67YC;J]n=z  
akxNT_   
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public String getSSiteURL() RhH1nf2UR  
{ K"H\gmV_g  
return sSiteURL; hlaN'j <C  
} 6(Pan%  
e~9O#rQI  
_XV%}Xb'  
public void setSSiteURL(String value) zKO7`.*  
{ pn gto  
sSiteURL = value; `za,sRFR  
} UJ)pae  
\=AA,Il  
8AuBs;i  
public String getSFilePath() fkBL`[v)4  
{ K^shTh8k  
return sFilePath; MC}t8L=  
} )U?_&LY)[M  
2T~cOH;T  
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public void setSFilePath(String value) GiV%Hcx  
{
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sFilePath = value; ;uUFgDi  
} }}JMwT  
/SD}`GxH  
wA=r]BT  
public String getSFileName() u0q$`9J  
{ s[yWBew  
return sFileName; tnRf!A;m  
} Tlsh[@Q  
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>='/%Ad  
public void setSFileName(String value) <'a~Y3B"o  
{ %ou,|Dww  
sFileName = value; jFj11w1FrA  
} =
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K}~$h,n  
!eLj+0  
public int getNSplitter() _ E;T"SC  
{ ]pax,|+$C  
return nSplitter; Zd*$^P,|  
} zfIo]M`  
zM9#1^X  
"O&93#8  
public void setNSplitter(int nCount) Jl Do_}  
{ ?+yr7_f3*  
nSplitter = nCount; :!`"GaTy  
} 9%!h/m>rW  
} U v2.Jo/Q  
`fu_){  
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k  
/* RLmOg{L  
**Utility.java
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*/ e7vm3<m4  
package NetFox; 6j
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:QE5 7.  
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public class Utility { TR"C<&y$j  
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Hq3|>OqC2Q  
public Utility() #@XBHJD\#  
{ z5+Pi:1w  
OxlA)$.hpu  
:cT)M(o  
} 2;}leZ@U  
p@<Q?  
//线程睡眠 0Y
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public static void sleep(int nSecond) NVyBEAoh  
{ )`u17 {  
try{ @KN+)qP  
Thread.sleep(nSecond); ( xs'D4  
} wj)LOA0  
catch(Exception e) &qv~)ZM$  
{ %pC<T*f  
e.printStackTrace (); %b6$N_M{H1  
} \Z-th,t  
} E C?}iP  
<I+kB^Er  
//日志 "F F$Q#)  
public static void log(String sMsg) X+hHEkJ  
{ /]
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System.err.println(sMsg); ]?9*Vr:P^  
} W5*ldXXk  
sS D8Sx/  
> I2rj2M#  
public static void log(int sMsg) JGs:RD'  
{ lZFu|(  
System.err.println(sMsg); &Mh.PzO=b  
} ' \JE>#  
} b!<_ JOL2.  
#M,&g{  
+8Xjk\Hi  
/* z7K{ ,y  
**TestMethod.java Hon2;-:]{]  
*/ 8 Rx@_  
package NetFox; i8iT}^  
5`;SI36"  
r- 8Awa  
public class TestMethod { j=WxtMS  
|OeyPD#  
,jU>V]YC  
public TestMethod() |v&)O)Jg  
{ ///xx/weblogic60b2_win.exe rrD
6x>  
try{ %hB-$nE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &@~K8*tmK  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "LBMpgpU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E`HoJhB  
fileFetch.start(); fSo8O  
} i~@gI5[k+  
catch(Exception e){e.printStackTrace ();} ]RVu[k8  
Mz@{_*2   
7?.uAiM'zT  
} w$]G$e  
7 N}@zPAZ  
}%g[1 #%(  
public static void main(String[] args) SN6 QX!3  
{ a>4/2#J  
new TestMethod(); b 74!Zw  
} E-A9lJW
r  
} UZdnsG7  
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