http断点续传简单实现（java)

/* c'TLD!^hB  
**SiteFileFetch.java R6o<p<fTh  
*/ DH*|>m&  
package NetFox; rd~W.b_b  
import java.io.*; dnc!=Z89  
import java.net.*; ]p.f*]  
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public class SiteFileFetch extends Thread { NJ!#0[@C  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -2Cf)>`v  
long[] nStartPos; //开始位置 w/Dm  
long[] nEndPos; //结束位置 zk~rKQ,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2l4i-;  
long nFileLength; //文件长度 t|"d#5'  
boolean bFirst = true; //是否第一次取文件 ;9\0x  
boolean bStop = false; //停止标志 Nmq5Tv  
File tmpFile; //文件下载的临时信息 mzR @P$:36  
DataOutputStream output; //输出到文件的输出流 =zGz|YI*?  
Rk0rHC6[  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Y[]t_o)  
public SiteFileFetch(SiteInfoBean bean) throws IOException {NqGWkGt*b  
{ w:@M|O4`  
siteInfoBean = bean; <:t\P.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +ANIm^@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S.>9tV2Ca  
if(tmpFile.exists ()) +-137!x\q  
{ #$)rwm.jW?  
bFirst = false; H pfI  
read_nPos(); =W^L8!BE'  
} Z6ex<[`I  
else ?kefRev<#h  
{ <4bo7XH  
nStartPos = new long[bean.getNSplitter()]; [cs8/Q8+  
nEndPos = new long[bean.getNSplitter()]; @(?d0xCg  
} L%Hm#eFx  
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} ;$;/#8`>  
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public void run() /aEQ3x  
{ 0~+:~$VrT  
//获得文件长度 tC~itU=V  
//分割文件 0R%58,R  
//实例FileSplitterFetch x"T^>Q  
//启动FileSplitterFetch线程 ?OdA`!wE  
//等待子线程返回 \Nyxi7  
try{ l'f!za0  
if(bFirst) !+l, m8Hly  
{ TC}u[kM  
nFileLength = getFileSize(); xq*yZ5:5Jo  
if(nFileLength == -1) B1.@K}  
{ Ww4G  
System.err.println("File Length is not known!"); O,6!`\ND  
} OaWq8MIZ-  
else if(nFileLength == -2) KrzM]x  
{ ( mMz]b5  
System.err.println("File is not access!"); |g+5rV
bd  
} ["/x~\c'N  
else U\6DEnII?!  
{ [D\AVx&  
for(int i=0;i<nStartPos.length;i++) _s,svQ8#  
{ \OH:xW~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [RuY'  
} $^>vJk<  
for(int i=0;i<nEndPos.length-1;i++) /HD2F_XA  
{ -l
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nEndPos = nStartPos[i+1]; r"
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} 5E=Odep`  
nEndPos[nEndPos.length-1] = nFileLength; mg]dKp  
} Ca|;8ggf  
} "TI? qoz  
tBQ> p.  
G8'3.;"W5  
//启动子线程 WKML#U]5T  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -]%@,L^@  
for(int i=0;i<nStartPos.length;i++) e)7r  
{ x N)Ck76  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Op~+yMef  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (1vS)v $L  
nStartPos,nEndPos,i); #\QC%"%f  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); voEc'JET  
fileSplitterFetch.start(); mD3#$E!A1  
} [8#l~ |U  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Qg=~n:j  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); h08T Q=n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", &|eQLY #l  
nEndPos = " + nFileLength); 2ra4t]f6  
// fileSplitterFetch[nPos.length-1].start(); hI0l2OE  
`Fr$q1qae{  
39#>C~BOl  
//等待子线程结束 _L>n!"E/  
//int count = 0; X.qKG0i  
//是否结束while循环 p10->BBg  
boolean breakWhile = false; WkE;tC*  
g=Jfp$*[  
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while(!bStop) 6WZp&pO  
{ P])O\
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write_nPos(); K~R{q+  
Utility.sleep(500); C/G[B?:h  
breakWhile = true; j/&7L@Y  
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for(int i=0;i<nStartPos.length;i++) H#K|SSqY?  
{ ,H8Pmn?  
if(!fileSplitterFetch.bDownOver) tTal<4  
{ uDR(^T{g#  
breakWhile = false; X,~C&#  
break; ~MF. M8  
} _nUuiB>  
} (X/JXu{  
if(breakWhile) "^`AS"z'  
break; qS>el3G  
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Y  
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//count++; X*@Sj;|m  
//if(count>4) Tec6] :  
// siteStop(); tEl_A"^e  
} D@e:Fu1\R  
KC'{>rt7  
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System.err.println("文件下载结束！"); %BJ V$tO  
} ?FyA2q!  
catch(Exception e){e.printStackTrace ();} dL>ZL1.$  
} ,O(uuq  
&I8ZVtg  
L`6`NYR  
//获得文件长度 XQ>m8K?\d  
public long getFileSize() CAf
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{ -VL3em|0  
int nFileLength = -1; Jh1fM`kB5K  
try{ 8}2 `^<U  
URL url = new URL(siteInfoBean.getSSiteURL()); MeC@+@C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~7|z2L  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^<c?Ire  
K2JS2Y]  
H|]Q;,C  
int responseCode=httpConnection.getResponseCode(); >K3Lww)Ln  
if(responseCode>=400) ?]S*=6  
{ 'tekn
e  
processErrorCode(responseCode); V0>,Kxk  
return -2; //-2 represent access is error > ewcD{bt  
} ? T9-FGW  
p)`JVq,H/B  
@xo9'M<l  
String sHeader; 7y!{lr=n  
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for(int i=1;;i++) -4.+
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{ _ ._'\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); U:H*b{`TU  
//Utility.log(in.readLine()); 1jR<H$aS  
sHeader=httpConnection.getHeaderFieldKey(i); 6v-h!1p{u  
if(sHeader!=null) YvonZ  
{ p4=^ UP  
if(sHeader.equals("Content-Length")) z
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{ nL
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); k2~j:&p  
break; OvkYzI`  
} yfj<P/aA+  
} u7K0m! jW  
else 1:?WvDN=  
break; \7RP6o  
} 'Q# KjY
 
} ].eGsh2  
catch(IOException e){e.printStackTrace ();} V<b"jCXI  
catch(Exception e){e.printStackTrace ();} >5\rU[H>  
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"Mth<%i  
Utility.log(nFileLength); 'j|;M  
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2!A/]
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return nFileLength; d:3G4g  
} WK-WA$7\  
6H@=O1W
  
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//保存下载信息（文件指针位置） rxO|k0x^C  
private void write_nPos() DF<_
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{ L49`=p<  
try{ }JS?42CTaV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^XV$J-  
output.writeInt(nStartPos.length); ^j@,N&W:lG  
for(int i=0;i<nStartPos.length;i++) [!"u&iu`  
{ CZ|R-ky6p  
// output.writeLong(nPos); l78zS'  
output.writeLong(fileSplitterFetch.nStartPos); vNP,c]:%  
output.writeLong(fileSplitterFetch.nEndPos); DEIn:d  
} EI'(  
output.close(); N/(&&\3  
} OX!9T.j  
catch(IOException e){e.printStackTrace ();} QM OOJA  
catch(Exception e){e.printStackTrace ();} n(&6E3ZcI  
} ;sDFTKf  
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//读取保存的下载信息（文件指针位置） P'[w9'B  
private void read_nPos() P7Kp*He)  
{ Eg>MG87  
try{ _jp8;M~Z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0EOpK%{  
int nCount = input.readInt(); bPWIf*3#  
nStartPos = new long[nCount]; |+%K89W  
nEndPos = new long[nCount]; &q>=6sQvf  
for(int i=0;i<nStartPos.length;i++) \59+JLmP4  
{ uk16  
nStartPos = input.readLong(); +h"RXwlBM  
nEndPos = input.readLong(); |dK_^~;o  
} UW!!!  
input.close(); ,JX/`7y  
} ygh*oVHO  
catch(IOException e){e.printStackTrace ();} M(xd:Fa?  
catch(Exception e){e.printStackTrace ();} ;a2TONW   
} 42mdak}\  
{2A/@$?  
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private void processErrorCode(int nErrorCode) ?Yxk1Y4ig)  
{ 7Q2"]f,$CQ  
System.err.println("Error Code : " + nErrorCode); \f.ceh;!  
} 52=?! JM  
49cQA$Ad  
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//停止文件下载 |d&a&6U:  
public void siteStop() *22}b.)  
{ >zVj+  
bStop = true; 6s@'z<Ct  
for(int i=0;i<nStartPos.length;i++) GHfsq|*j,Z  
fileSplitterFetch.splitterStop(); UT%^!@u  
7*`cWT_X  
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} /2 ')u|  
} gq!|0  
//负责部分文件的抓取 1d,;e:=j  
**FileSplitterFetch.java =otJf
~  
*/ Nw* >$v  
package NetFox; 3+rud9T  
adRvAq]mA  
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import java.io.*;  1)U%p  
import java.net.*; rfku]A$  
?*){%eE  
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public class FileSplitterFetch extends Thread { N;Wm{~Zhb  
8wMu^3r  
,SNN[a  
String sURL; //File URL D<78Tm x  
long nStartPos; //File Snippet Start Position sE{A~{a`  
long nEndPos; //File Snippet End Position ]X%T^3%G  
int nThreadID; //Thread's ID 9q(*'rAm  
boolean bDownOver = false; //Downing is over >fNRwmi  
boolean bStop = false; //Stop identical V*U{q%p(  
FileAccessI fileAccessI = null; //File Access interface Ey4%N`H-^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 'tm%3` F  
{ WW\t<O;z  
this.sURL = sURL; k` cz$>  
this.nStartPos = nStart; :+: vBrJm  
this.nEndPos = nEnd; ;Sl]8IZ  
nThreadID = id; [oqb@J2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =^#^Mq)  
} lu2"?y[2  
<?znk8|  

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public void run() kwF4I)6  
{ U51C /A  
while(nStartPos < nEndPos && !bStop) Q4i@y6z  
{ =wE1j  
'[V}]Z>-  
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try{ +X#JCLD  
URL url = new URL(sURL); ]rU$0)VN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [Vzp D 4  
httpConnection.setRequestProperty("User-Agent","NetFox"); FtHR.S=u  
String sProperty = "bytes="+nStartPos+"-"; WCJ$S\#  
httpConnection.setRequestProperty("RANGE",sProperty); QU{|S.\  
Utility.log(sProperty); b5NPG N  
M*6}#ST  
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InputStream input = httpConnection.getInputStream(); x=]PE}<E  
//logResponseHead(httpConnection); 2?J[D7  
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byte[] b = new byte[1024]; #4?Z|_j3  
int nRead; RHe'L36W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) bruM#T@}  
{ &ZmWR  
nStartPos += fileAccessI.write(b,0,nRead); ]w*w@:Zk  
//if(nThreadID == 1) {\u=m>2U|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D}YAu,<K  
} d'y\~M9(  
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Utility.log("Thread " + nThreadID + " is over!"); BTi:Bcv k  
bDownOver = true; vOMmsU F  
//nPos = fileAccessI.write (b,0,nRead); Bg3`w__l;  
} ,j^z];  
catch(Exception e){e.printStackTrace ();} <B"M} Y>_P  
} N3O~_=/v?  
} UM[<v9NWE  
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^6c=[N$aW  
//打印回应的头信息 =\uQGH  
public void logResponseHead(HttpURLConnection con) wX7|a/|@  
{ c:>&iB-Yu  
for(int i=1;;i++) ZoFQJJK56B  
{ xweV8k/  
String header=con.getHeaderFieldKey(i); Y
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if(header!=null) 3"9'MDKH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); GP|G[  
Utility.log(header+" : "+con.getHeaderField(header)); ur*@TIvD  
else ;G 27S<Q  
break; 3JnBKh\n  
} Dj0`#~  
} %#g9d  
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~
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public void splitterStop() .@7J8FS*  
{ 6@N?`6Bt  
bStop = true; pyvZ[R9  
} /1s|FI$-L  
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} L!fiW`>0G  
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/* TttD}`\.  
**FileAccess.java +aa( YGL  
*//文件访问(定位，写) {Vg8pt  
package NetFox; 7-*QF>w<a  
import java.io.*; IYb%f T  
<|,0%bq)|  
Xn<~ln  
public class FileAccessI implements Serializable{ H?ZlJ|/c  
` #!~+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Ujw J}j  
RandomAccessFile oSavedFile; }1N$4@  
long nPos; zQ[g*  
)qi/>GR,  
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public FileAccessI() throws IOException [5KzawV  
{ HkH!B.H]  
this("",0); ^Md
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} u2p5*gzZ  

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public FileAccessI(String sName,long nPos) throws IOException }
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{ 1O<Gg<<,e  
oSavedFile = new RandomAccessFile(sName,"rw"); 5)%b
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this.nPos = nPos; ,<,ige  
oSavedFile.seek(nPos); =e<;B_~.  
} y1zNF$<q  
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public synchronized int write(byte[] b,int nStart,int nLen) Z @:5vo  
{ u!iBAr5  
int n = -1;
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try{ ubq4Zv7'   
oSavedFile.write(b,nStart,nLen); ulcm  
n = nLen; X<6Ro es2  
} co <ATx  
catch(IOException e) ]6PX4oK_t  
{ A (:7q4  
e.printStackTrace (); UIpW#t  
} cy0 %tsB|  
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return n; bo;;\>k  
} a,B2;4"  
)+
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} 2<Vw :+,  
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/* 
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**SiteInfoBean.java "K.XoG4|  
*/ Nk~Xz  
package NetFox; $Vu%4kq  
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public class SiteInfoBean { u!&w"t61Nd  
bu;3Ib3\  
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private String sSiteURL; //Site's URL %SWtE5HZQq  
private String sFilePath; //Saved File's Path KJ7[DN'(  
private String sFileName; //Saved File's Name 1x\Vz\  
private int nSplitter; //Count of Splited Downloading File rZ.,\ X_  
!11x&Db  

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public SiteInfoBean() _`Ojh0@00  
{//nSplitter的缺省值为5 @B<B#  
//default value of nSplitter is 5 <NIg`B@'s  
this("","","",5); 0SoU\/kUi  
} bzz{ p1e  
$_
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qDOJ;>I  
{ f zu#!  
sSiteURL= sURL; (9;qV:0`  
sFilePath = sPath; oiG@_YtR  
sFileName = sName; S6.N)7y  
this.nSplitter = nSpiltter; %s]l^RZ  
n+5X*~D  
c|f)k:Q  
} 5H+S=  
<Pg]V:=g'  
MX3ss,F  
public String getSSiteURL() v-*CE[  
{ j( *;W}*^  
return sSiteURL; IIN"'7Z^R  
} V;b^b5yZ>  
&hK5WP6whW  
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public void setSSiteURL(String value) mY+.(N7m  
{ Ov vM)?^#  
sSiteURL = value; (#w8/@JxF  
} ` ]*KrY  
8}Pd- .se  
bL=32YS  
public String getSFilePath() 8[\(*E}d!X  
{ +6vm4(3?  
return sFilePath; Y(>]7  
} YF{KSGq  
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{C=d9z~:  
public void setSFilePath(String value) gE,i
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{ cZ(7/Pl  
sFilePath = value; +C~,q{u  
} D`r^2(WW  
GHQa{@m2V  
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public String getSFileName() 'ADaz75`*r  
{ E'p5  
return sFileName; %@<
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} U=<E,tM  
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k~ZwHx(%S  
public void setSFileName(String value) =2VM(GtK>  
{ opz.kP[e,  
sFileName = value; H6<\7W89y  
} uJ S+;H  
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6gS<h\h0  
public int getNSplitter() =bUVGjr%96  
{ !<"H73?fl  
return nSplitter; r4}:t$  
} ;{]%ceetcu  

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public void setNSplitter(int nCount) W,zlR5+Jk  
{ Or&TGwo I  
nSplitter = nCount; F+vgkqs@9  
} f\oB/  
} GgH=w`;_  
]Mv.Rul?~  
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/*  ]A;zY%>  
**Utility.java E<>Ev_5>  
*/ 6:i(<7  
package NetFox; #UH|,>W6  
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public class Utility { \WD}@6) ~  
<C\snB  
/H+j6*}r  
public Utility() Mn(:qQo^&`  
{ brN:Ypf-e  
6xSdA;<+]  
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} 3_(fisvx  
n!mtMPH$  
//线程睡眠 <J=9,tv<  
public static void sleep(int nSecond) |$`LsA.  
{ m(nGtrQJm  
try{ V7u;"vD  
Thread.sleep(nSecond); C=}YKsi|R|  
} u"-q"0
 
catch(Exception e) *]
%{ttR~  
{ X)d7y  
e.printStackTrace (); ysA~Nq@  
} $b;9oST  
} oB8u[!  
iXtar;%  
//日志 B8z3W9  
public static void log(String sMsg) ,u|vpN  
{ U/E M(y  
System.err.println(sMsg); S?nXpYr  
} uzL)qH$b  
#_{3W-35*  
HK>!%t0S  
public static void log(int sMsg) f.0~HnNg1  
{ mM"!=' z  
System.err.println(sMsg); `,ZsKxI  
} M xUj7ae  
} %-?HC
jT  
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/* 7g3vh%G.  
**TestMethod.java *M;!{)m?  
*/ -~eNC^t;W  
package NetFox; !+&"y K@J  
\{L!hAw  
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public class TestMethod { F*hOa|7/  
O-6848iCX  
k}y1IW+3  
public TestMethod() [*w^|b?  
{ ///xx/weblogic60b2_win.exe $6 \v1
 
try{ %qR
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9mkt.>$  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); po+>83/!oq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2SEfEkk  
fileFetch.start(); <jXXj[M2  
} \?&P|7N  
catch(Exception e){e.printStackTrace ();} +N2?fgA  
dK,j|  
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} 8D[P*?O  
]+Yd#<j(u  
A-r-^S0\  
public static void main(String[] args) hZ-No  
{ "ZF:}y  
new TestMethod(); !
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} x2+%.$'  
} HMJx[ yD  
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