http断点续传简单实现（java)

/* "(Mvl1^BT  
**SiteFileFetch.java ]^Sd9ba  
*/ 0Ulxp  
package NetFox; 5P-K *C&  
import java.io.*; $Vo/CZW7  
import java.net.*; 8FAT(f//.  
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public class SiteFileFetch extends Thread { <9=zP/Q  
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SiteInfoBean siteInfoBean = null; //文件信息Bean wYZye^7  
long[] nStartPos; //开始位置 W/b"a?wE{  
long[] nEndPos; //结束位置 s.f`.o  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 d&/^34gn  
long nFileLength; //文件长度 )C'G2RV  
boolean bFirst = true; //是否第一次取文件 ` 52%XI  
boolean bStop = false; //停止标志 =9kj? u~  
File tmpFile; //文件下载的临时信息 ]\[m=0K  
DataOutputStream output; //输出到文件的输出流 -0{T
 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） P h9Hg'  
public SiteFileFetch(SiteInfoBean bean) throws IOException oxUE79  
{ t8L<x  
siteInfoBean = bean; KDux$V4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); += X).X0K  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v]B0!k&4.  
if(tmpFile.exists ()) ~sZqa+jB0  
{ `6|i&w:b  
bFirst = false; |E46vup  
read_nPos(); t.3Ct@wK  
} s]$HkSH  
else lo\:]/&6  
{ JQ~y- lt  
nStartPos = new long[bean.getNSplitter()]; D=jSh  
nEndPos = new long[bean.getNSplitter()]; *rS9eej  
} qFV;n
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} t#fs:A7P?}  
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public void run() 2z'+1+B'  
{ m-:8jA?  
//获得文件长度 5}vRo;-  
//分割文件 vF5wA-3&t  
//实例FileSplitterFetch 8 m%>:}o  
//启动FileSplitterFetch线程 \h
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//等待子线程返回 s-QM6*  
try{ nAQyxP%  
if(bFirst) QH@Q\ @,  
{ fG:PdIJ7_  
nFileLength = getFileSize(); Xz;et>UD*B  
if(nFileLength == -1) ;X?Ah  
{ TYs+XJ'Xj  
System.err.println("File Length is not known!"); ]jHh7> D  
} >wz;}9v  
else if(nFileLength == -2) y#hga5  
{ <;2P._oZ  
System.err.println("File is not access!"); }"F ?H:\  
} 4yA9Ni  
else ?b!CV   
{ ti$oZ4PpF  
for(int i=0;i<nStartPos.length;i++) N&6_8=3z  
{ b@nri5noBm  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .`oJcJ  
} b&\3ps  
for(int i=0;i<nEndPos.length-1;i++) jF%)Bhn(  
{ W&fW5af
9  
nEndPos = nStartPos[i+1]; @4 zi]v  
} ek<PISlci  
nEndPos[nEndPos.length-1] = nFileLength; hQgk.$g  
} ib5
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} oV0LJ%  
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//启动子线程 #6Efev  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _n-VgPRn  
for(int i=0;i<nStartPos.length;i++) v#Cz&j  
{ W0
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 37j\D1Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), mQwk!* U  
nStartPos,nEndPos,i); t9Enk!@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *r)zBr  
fileSplitterFetch.start(); 21[K[ %  
} _&k'j)rg  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7Y-FUZ.`>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &+)+5z_d  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p9FA_(`^  
nEndPos = " + nFileLength); WUE)SVf  
// fileSplitterFetch[nPos.length-1].start(); N<#S3B?.  
&&(4n?   
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//等待子线程结束 e.)yV'%L  
//int count = 0; }};j2  
//是否结束while循环 1kB'sc3N
!  
boolean breakWhile = false; SQO>}#qm  
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{ 4_I7r  
while(!bStop) d-6sC@PB  
{ ,wwU` U  
write_nPos(); f7EIDFX>pt  
Utility.sleep(500); &^CL]&/  
breakWhile = true; 2.fyP"P L  
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for(int i=0;i<nStartPos.length;i++) ImUQ*0  
{ bqw/O`*wfN  
if(!fileSplitterFetch.bDownOver) /t$+Af,}  
{ D\45l  
breakWhile = false; ifJv~asp   
break; J[j/aDdP  
} ue6/EN;}  
} ,$MWk(S  
if(breakWhile) bm|Jb"T0b  
break; )1ZJ  
B|]t\(~$[  
,(@Y%UW:  
//count++; %fn'iKCB  
//if(count>4) "k\Ff50  
// siteStop(); JEK%yMj  
} >\6jb&,%O  
I,],?DQX2)  
2- Npw%;  
System.err.println("文件下载结束！"); x*loACee.  
} GsP@ B'  
catch(Exception e){e.printStackTrace ();} `@fhge  
} XhlI|h
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()JYN5  
!^Z[

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//获得文件长度 -)y> c  
public long getFileSize() U(S@1i(  
{ EO o'a  
int nFileLength = -1; N27K  
try{ WryW3];0OR  
URL url = new URL(siteInfoBean.getSSiteURL()); )*^OPVt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K]H"qG.K  
httpConnection.setRequestProperty("User-Agent","NetFox"); z._C*c  
?{@!!te@3v  
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int responseCode=httpConnection.getResponseCode(); \jF" nl  
if(responseCode>=400) vc>^.#7
 
{ *7xQp!w^  
processErrorCode(responseCode); +Y
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return -2; //-2 represent access is error fw(j6:p  
} MYDf`0{$_a  
jt'Y(u]2  
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String sHeader; 4t+/
 
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%  
for(int i=1;;i++) xVHQ[I%  
{ eu}:Wg2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); i h`y0(<  
//Utility.log(in.readLine()); Pjj;.c 7_j  
sHeader=httpConnection.getHeaderFieldKey(i); Pq{YZMr  
if(sHeader!=null) 26('V `N  
{ ,{`o/F/  
if(sHeader.equals("Content-Length")) t(z(-G|&  
{ cjy0s+>>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); n7`.<*:  
break; Sq?6R}q%  
} >n$EeJ  
} ;4S [ba1/  
else ?v
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break; $X.'W\o|  
} hIzPy3  
} %~B)~|h  
catch(IOException e){e.printStackTrace ();} \0*yxSg,^  
catch(Exception e){e.printStackTrace ();} >PTu*6Z  
/\3XARt  
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Utility.log(nFileLength); \K_!d]I {  
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return nFileLength; VxPTh\O*[  
} |j5AU  
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;K)?:  
//保存下载信息（文件指针位置） `3
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private void write_nPos() L!+[]tB  
{ )K\k6HC.  
try{ P60]ps!M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +NzD/.gq  
output.writeInt(nStartPos.length); My6]k?;}(  
for(int i=0;i<nStartPos.length;i++) x%:>Ol  
{ !cFE^VM_;  
// output.writeLong(nPos); ,h^;~|GT  
output.writeLong(fileSplitterFetch.nStartPos); <2TB9]2. g  
output.writeLong(fileSplitterFetch.nEndPos); X/;"CM  
} R<0!?`b  
output.close(); ,39$iHk  
} 3$kv%uf{  
catch(IOException e){e.printStackTrace ();} x9&tlKKxf  
catch(Exception e){e.printStackTrace ();} JI[rIL\Ey  
} *\~kjZ 3  
66"ZH,335  
9%)& }KK|  
//读取保存的下载信息（文件指针位置） j_ywG{Jk  
private void read_nPos() G"UH4n[1ur  
{ I8-&.RE  
try{ QLpTz"H  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *>&N t  
int nCount = input.readInt(); K_lCDiqG  
nStartPos = new long[nCount]; 0R%uVJG  
nEndPos = new long[nCount]; On96N|  
for(int i=0;i<nStartPos.length;i++) S}xDB  
{ (?&_6B.*  
nStartPos = input.readLong(); ["#A-S  
nEndPos = input.readLong();
+DV6oh  
} o7 -h'b-  
input.close(); C"m0"O>  
} tpx3:|  
catch(IOException e){e.printStackTrace ();} -)vp&-  
catch(Exception e){e.printStackTrace ();} n]ppO U|[  
} {;z L[AgCg  
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private void processErrorCode(int nErrorCode) K7&8;So  
{ GE3U0w6WbK  
System.err.println("Error Code : " + nErrorCode); $qyM X[  
} >G3J3P(  
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o}^vREO  
//停止文件下载 I3E8vi%B.  
public void siteStop() iDkWW  
{ `bi_)i6Low  
bStop = true; ~3-YxCn%  
for(int i=0;i<nStartPos.length;i++) oj4)7{  
fileSplitterFetch.splitterStop(); }HQT@&=  
,IVr4#w0=  
+KwF U  
} e[k;SSs  
} oWaIjU0  
//负责部分文件的抓取 H
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**FileSplitterFetch.java uF.\dY\xv  
*/ r0$9c  
package NetFox; TI7Ty+s  
 /qQ2@k  
1.d9{LO[-  
import java.io.*; MPEBinE?  
import java.net.*; 7Hkf7\JY  
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public class FileSplitterFetch extends Thread { 1oW]O@R  
uA}FuOE6  
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String sURL; //File URL Exs _LN  
long nStartPos; //File Snippet Start Position +MoxvW6  
long nEndPos; //File Snippet End Position ! {o+B^^  
int nThreadID; //Thread's ID PM?Ri^55<L  
boolean bDownOver = false; //Downing is over ` Ehgn?6'  
boolean bStop = false; //Stop identical
}Yl8Q>t  
FileAccessI fileAccessI = null; //File Access interface "s6_lhu=E7  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ky~~Cd$  
{ eEZlVHM;O  
this.sURL = sURL; ]A<u eM  
this.nStartPos = nStart; 8Carg~T@  
this.nEndPos = nEnd; @U.}Ei  
nThreadID = id;  F-\8f(\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 tlxjs]{0E  
} IEsD=  
e=Tc(Mwn  
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public void run() Pg8=  
{ iU+,Jeu  
while(nStartPos < nEndPos && !bStop) -Aym+N9  
{ ^EBM;&;7  
3UtXxL&L`  
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try{ cZ2, u,4  
URL url = new URL(sURL); }~,cCtg:o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J3SbyI
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httpConnection.setRequestProperty("User-Agent","NetFox"); ;A'1
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String sProperty = "bytes="+nStartPos+"-"; l#f]KLv4N_  
httpConnection.setRequestProperty("RANGE",sProperty); \
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Utility.log(sProperty); <EN[s  
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InputStream input = httpConnection.getInputStream(); 2<./HH*f  
//logResponseHead(httpConnection); ;}9Ws6#XQs  
^p%+rB.j[  
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byte[] b = new byte[1024]; zyn =Xv@p  
int nRead; B-p5;h>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) w3|.4hS  
{ hfa_M[#Q-  
nStartPos += fileAccessI.write(b,0,nRead); ' g!_Flk  
//if(nThreadID == 1) NP`ll0s  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); en6AAr:U}  
} {
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NbMH@6%E  
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Utility.log("Thread " + nThreadID + " is over!"); bD[W
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bDownOver = true; \bmboNe  
//nPos = fileAccessI.write (b,0,nRead); t4W0~7  
} 2Sd6b 2-  
catch(Exception e){e.printStackTrace ();} &`y_R'  
} {YLJKu!M  
} p.Yg-CA  
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//打印回应的头信息 WSccR  
public void logResponseHead(HttpURLConnection con) 1,D ^,  
{ aL6 5t\2  
for(int i=1;;i++) %31K*i/]  
{ ?O^:j!C6  
String header=con.getHeaderFieldKey(i); qGUe0(
  
if(header!=null) <.XoC?j  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,(?4T
~  
Utility.log(header+" : "+con.getHeaderField(header)); RwHXn]
1  
else Os]M$c_88  
break; j~> #{"C  
} %Ne>'252y  
} X
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*Z(C')7r  
public void splitterStop() 9 f/tNQ7W  
{ e';c8WF3E  
bStop = true; EB<tX`Wp  
} f3|=T8"t  
Q#bo!]H{t  
*3oQS"8  
} oQB1fs  
'B:De"_(N  
Q%d[U4@  
/* *#9kFz-  
**FileAccess.java Ykq
}9  
*//文件访问(定位，写) +a@SdWf  
package NetFox; X2kL
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import java.io.*; bTKxv<  
g{{SY5qDj  
m5
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public class FileAccessI implements Serializable{ oK[,xqyA  
e+aQ$1^t  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 FJ. :*K[  
RandomAccessFile oSavedFile; jH/%Z5iu  
long nPos; LM`#S/h  
0$uS)J\;K  
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public FileAccessI() throws IOException WL]'lSHa  
{ o?8j*
]  
this("",0); .v8
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} N=x,96CF  
N/.9Aj/h~&  
GY :IORuA4  
public FileAccessI(String sName,long nPos) throws IOException Ghe=hhZ  
{ JYUKs~Qt  
oSavedFile = new RandomAccessFile(sName,"rw"); *xKR;?.  
this.nPos = nPos; 6-}9m7#Y  
oSavedFile.seek(nPos); -^N '18:  
} %"B$I>h  

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Pk2"\y@q/  
public synchronized int write(byte[] b,int nStart,int nLen) Z)4P>{  
{ YZD]<
ptR  
int n = -1; 
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try{
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oSavedFile.write(b,nStart,nLen); pp_ddk  
n = nLen; Etk<`GRfA  
} bsVOO9.4-  
catch(IOException e) L2tmo-]nw  
{ %
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e.printStackTrace (); ?os0JQVB  
} EaL+}/q&  
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\hX^Cn=6  
return n; evP`&23t
P  
} Ric$Xmu
  
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4QDzG~N4)|  
} 9`b3=&i\  
.!! yj,bQz  
sk/Mh8z  
/* bZJ
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**SiteInfoBean.java dD!SgK[Jv  
*/ N9Vcp~;  
package NetFox; **[p{R]8o  
b*7i&q'H  
z""
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public class SiteInfoBean { !b_IH0]U  
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private String sSiteURL; //Site's URL bSzb! hT`  
private String sFilePath; //Saved File's Path `WL*Jb  
private String sFileName; //Saved File's Name a WC sLH  
private int nSplitter; //Count of Splited Downloading File ujBADDwOg)  
lnUy?0(  
=n&83MYX  
public SiteInfoBean() P'';F}NwfX  
{//nSplitter的缺省值为5 V00zk`PH  
//default value of nSplitter is 5 4|UIyDt8  
this("","","",5); #{a<{HX  
} (C|%@61S  
zyE yZc?  
v%w]Q B  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fk_i~K  
{ _9dV 3I  
sSiteURL= sURL; Adm`s .  
sFilePath = sPath; 9`{cX  
sFileName = sName; hCrgN?Mz  
this.nSplitter = nSpiltter; *G38N]|u6  
JJr<cZ4]  
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} *{bqHMd4L  
[;bLlS,  
12E"6E)
 
public String getSSiteURL() }K\_N]#6n  
{ u-$AFSt  
return sSiteURL; +iR;D$w  
} aJts  
>#Yq&@G  
)sr]}S0  
public void setSSiteURL(String value) Qy%/+9L  
{ :A[/;|&  
sSiteURL = value; H#:Yw|t  
} 70Am]L&M  
9v A`\\9  
4+0Zj+ q";  
public String getSFilePath() 62q-7nV  
{ Y;WrfO$J  
return sFilePath; -K{ID$!p  
} 0ni5:tYy  
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1vr/|RWW  
public void setSFilePath(String value) gkjZX wp  
{ n >^?BU  
sFilePath = value; S_atEmQ  
}
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)_ y{^kn3^  
public String getSFileName() Vl%
k:  
{ aap:~F{]X  
return sFileName; i8]r}a  
} !WmpnPr1  
w@4+
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@9L9c  
public void setSFileName(String value) k dqH36&<  
{ @NF8?>!  
sFileName = value; f{J7a1 `_  
} "(5}=T@,  
>;Bhl|r~z  

d$ /o\G  
public int getNSplitter() 0WFZx Ad"  
{ U8dwb  
return nSplitter; )]}*oO  
} 2;3q](d   
=[$*PTe  
kF5}S8B  
public void setNSplitter(int nCount) xiiZ'U  
{ p ,!`8c6  
nSplitter = nCount; ;Mc}If*  
} 9f "*Oj  
} CfAqMH*ip  
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x8H)m+AW  
/* qy!G&  
**Utility.java l/]P6 @N  
*/ Kfi A 7W  
package NetFox; cb+!H>+  
R#t~i&v/  
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public class Utility { 4xlsdq8`t  
P_;oSN|>  
LZeR.8XM>  
public Utility() ;rFa I^  
{ srCjq  
1yo@CaW[\  
;RrfE8mGj  
} # a3Q<%V  
H/b(dbs  
//线程睡眠 yP@=x!$  
public static void sleep(int nSecond) }E=mZZ
)  
{ m=R4A4Y7  
try{ U>>J_2  
Thread.sleep(nSecond); o)$sZ{` ="  
} 67e1Y@Xu  
catch(Exception e) 3|A"CU/z@  
{ 6 3HxQH  
e.printStackTrace (); 0YS*=J"7z  
} q*T+8O  
} cc>h=%s`  
-{O2Nv-]]  
//日志 qAU]}Et/  
public static void log(String sMsg) f7`y*9^  
{ sU8D;ML7  
System.err.println(sMsg); \nLO.,  
}
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`@ObM[0p(  
{>i'Pb0mG|  
public static void log(int sMsg) l6O2B/2
j  
{ 71~V*  
System.err.println(sMsg); wxoBq{r;  
} L3/ua  
} U{ Y)\hR-  
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i,~{{XS<  
/* (<f[$ |%  
**TestMethod.java N>/U%01a  
*/ wC[J=:]tA5  
package NetFox; -0W;b"]+A  
6 2LZ}yn_"  
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public class TestMethod { ]t,ppFC#  
qn<~ LxQ  
^Ab|\5^3  
public TestMethod() Oz+>I^Q  
{ ///xx/weblogic60b2_win.exe ]!f=b\-Av  
try{ _K9jj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A_[65'*b  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =.uE(L`]NA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }NUP[%
  
fileFetch.start(); 8T%z{A1T  
} old}}>_  
catch(Exception e){e.printStackTrace ();} +pE-Yn`YS  
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vX{]_  
} $GcVC (]  
lAoH@+dyA+  
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public static void main(String[] args) 5r.{vQ  
{ K(_n
fE{  
new TestMethod(); -JcfP+{wS  
} ;}r#08I  
} )37|rB
E  
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