http断点续传简单实现（java)

/* tsf!Q  
**SiteFileFetch.java 2/l4,x  
*/ R)9FXz$).  
package NetFox; mz^[C7(q'(  
import java.io.*;
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import java.net.*; 9`DY6qfly  
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public class SiteFileFetch extends Thread { jHc/ EZB  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -257g;  
long[] nStartPos; //开始位置 OC2%9Igx0  
long[] nEndPos; //结束位置 ~;nW+S$o  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 GC~N$!*  
long nFileLength; //文件长度 _2Fa.gi  
boolean bFirst = true; //是否第一次取文件 ZRCUM
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boolean bStop = false; //停止标志 20mZ{_%  
File tmpFile; //文件下载的临时信息 9!Vp-bo  
DataOutputStream output; //输出到文件的输出流 }/Y)^  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 0
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public SiteFileFetch(SiteInfoBean bean) throws IOException axd9b,  
{ "RsH
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siteInfoBean = bean; Re'Ek  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p2o66t  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?a-}1A{  
if(tmpFile.exists ()) w7h=vy n?  
{ 7=]Y7"XCf  
bFirst = false; 7.xJ:r|  
read_nPos(); $a+)v#?,  
} r#K"d  
else m{sc
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{ j_~lc,+m  
nStartPos = new long[bean.getNSplitter()]; zGE{Z A  
nEndPos = new long[bean.getNSplitter()]; &8 4Izs/[  
} ]lzOz<0q  
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} GE.@*W  
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public void run() J*O$)K%Hx  
{ )ur&Mnmm  
//获得文件长度 BXo9s~5Q  
//分割文件 Yg14aKZl  
//实例FileSplitterFetch $Uxg$pqO  
//启动FileSplitterFetch线程 JSm3ZP|GqJ  
//等待子线程返回 )d-
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try{ E.~~.2   
if(bFirst) T?E[LzZg  
{ @Ao E>  
nFileLength = getFileSize(); S~DY1e54GF  
if(nFileLength == -1) K1>(Fs$  
{ EaGS}=qY5  
System.err.println("File Length is not known!"); !4G<&hvb  
} &g<`i
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else if(nFileLength == -2) mF !=H%  
{ D?"TcA  
System.err.println("File is not access!"); rfNt  
}
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else VG`A* Vj  
{ l?%U*~*  
for(int i=0;i<nStartPos.length;i++) =F}e>D  
{ lCyp&b#(L  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8;s$?*Gi  
} I"=XM   
for(int i=0;i<nEndPos.length-1;i++) )(pJ~"'L  
{ %7?v='s=  
nEndPos = nStartPos[i+1]; P&Q 5ZQb  
} XJ;JDch  
nEndPos[nEndPos.length-1] = nFileLength; [Pt5c6L:  
} BDg6ZI<n  
} :I}_  
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^MWfFpJV!]  
//启动子线程 Do|`wpR  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; U)p P^:|  
for(int i=0;i<nStartPos.length;i++) o;JBe"1  
{ `
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A4?_0:<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), S-h1p`  
nStartPos,nEndPos,i); .j4IW3)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jL)aU> kN  
fileSplitterFetch.start(); 4>^ %_Xj[  
} `#X{
.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gGU3e(!Uc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); V@K}'f~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ls6ywLP{  
nEndPos = " + nFileLength); Q_#X*I  
// fileSplitterFetch[nPos.length-1].start(); o=_4v^  
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/kVy#sT|  
//等待子线程结束 ^dYLB.'=  
//int count = 0; r/L
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//是否结束while循环 =k`(!r2"#  
boolean breakWhile = false; N[Arw
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while(!bStop) s:cS 9A8  
{ 4aB`wA^x  
write_nPos(); xMhR;lKY  
Utility.sleep(500); $YaL3n  
breakWhile = true; p9_45u`u2  
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for(int i=0;i<nStartPos.length;i++) O,JthlAV4  
{ 1xq1te)  
if(!fileSplitterFetch.bDownOver) 3g2t{%  
{ kC9A  
breakWhile = false; *vsOL4I%  
break; +Mm0
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} rT}d<cSf  
} -3_kS/  
if(breakWhile) ~w[zX4@  
break; TJsT .DWW~  
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//count++; !b _<_Y{l  
//if(count>4) ~?b(2gn  
// siteStop(); a/)TJv  
} *bRH,u  
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System.err.println("文件下载结束！"); aeBth{  
} vlj|[joXw  
catch(Exception e){e.printStackTrace ();} sCRBKCR?  
} J;T_9  
[>_(q|A6+  
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//获得文件长度 l1W5pmhK]'  
public long getFileSize() cF v
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{ eIqj7UY_  
int nFileLength = -1; UN>hJN;c  
try{ u5CT7_#)  
URL url = new URL(siteInfoBean.getSSiteURL()); Ugdm"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %W&=]&L  
httpConnection.setRequestProperty("User-Agent","NetFox"); *iC t4J  
:&or'Yi}  
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int responseCode=httpConnection.getResponseCode(); i*U\~CZjT  
if(responseCode>=400) e&0B4wVAQ  
{ z~VA#8>  
processErrorCode(responseCode); Aoo'i  
return -2; //-2 represent access is error @$nI\n?*  
} aF;&#TsB  
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String sHeader; vy"Lsr3  
/p%K[)T(  
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for(int i=1;;i++) QKP9*dz  
{ ^g[])2",  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &J~S $  
//Utility.log(in.readLine()); _ma4  
sHeader=httpConnection.getHeaderFieldKey(i); 3x=F  
if(sHeader!=null) I Mv^ 9T:  
{ YwF6/JA0^  
if(sHeader.equals("Content-Length")) Z?X$8o^Z  
{ !gk\h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4vX]c  
break; bNaUzM!,H  
} ~NcJLU!au  
} oOL3O@)w>  
else FSQ&J|O  
break; V?O%kd  
} a:|4q  
} L$Leo6<3a  
catch(IOException e){e.printStackTrace ();} GY",AL8f  
catch(Exception e){e.printStackTrace ();} w7Pe<vT  
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Utility.log(nFileLength); nM; G; T  
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return nFileLength; j^ _I{  
} -oZac  
#pe{:f?  
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//保存下载信息（文件指针位置） >b["T+  
private void write_nPos() YT5>pM-%  
{ 38m%if
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try{ PD}R7[".>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &CL|q+-  
output.writeInt(nStartPos.length); v2n0[b0  
for(int i=0;i<nStartPos.length;i++) TN %"RL  
{ N#u8{\|8]  
// output.writeLong(nPos); p-pw*wH0  
output.writeLong(fileSplitterFetch.nStartPos); g&Z7h4!\  
output.writeLong(fileSplitterFetch.nEndPos); 4v|/+J6G  
} Ke ?uE  
output.close(); f)zg&Ib  
} Jrk^J6aa  
catch(IOException e){e.printStackTrace ();} |wJZU  
catch(Exception e){e.printStackTrace ();} rEhf_[Dv  
} $CmX &%L=  
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//读取保存的下载信息（文件指针位置） S(J\<)b  
private void read_nPos() )zXyV]xe  
{ u3wC}Zo  
try{ 5ZA%,pH>Jq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;1.>"zX(  
int nCount = input.readInt(); O^}v/}d  
nStartPos = new long[nCount]; ,w%oSlOu  
nEndPos = new long[nCount]; %<?ciU  
for(int i=0;i<nStartPos.length;i++) eh(Q^E;*  
{ p{a]pG+3  
nStartPos = input.readLong(); ^V}R(gDu}s  
nEndPos = input.readLong(); Tq84Fn!HJ>  
} tHtV[We.:  
input.close(); jAK{<7v4U  
}  xD  
catch(IOException e){e.printStackTrace ();} O4/n!HOb  
catch(Exception e){e.printStackTrace ();} ,Us2UEWNv  
} {1MGb%xW  
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private void processErrorCode(int nErrorCode) sJb)HQ,7x  
{ }E5#X R  
System.err.println("Error Code : " + nErrorCode); }6J7<g  
} .NkAD-k`  
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P;[Y42\z|  
//停止文件下载 yvz?4m"_yB  
public void siteStop() -2&i)S0R  
{ 4C1FPrh  
bStop = true; cVay=5].  
for(int i=0;i<nStartPos.length;i++) 8*yo7q&  
fileSplitterFetch.splitterStop(); rAx"~l.=  
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} i~)NQmH<  
} ISS\uj63M  
//负责部分文件的抓取 Znta#G0  
**FileSplitterFetch.java %)axGbZG;  
*/ \V^*44+ <!  
package NetFox; _(6`{PWY  
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import java.io.*; nG"n-$A?<  
import java.net.*; L}W1*L$;<  
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public class FileSplitterFetch extends Thread { 4TUtY:  
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String sURL; //File URL d=XpO*v,[  
long nStartPos; //File Snippet Start Position / Mod=/e  
long nEndPos; //File Snippet End Position >?5xDbRj  
int nThreadID; //Thread's ID CE#\Roi x)  
boolean bDownOver = false; //Downing is over PK6*}y  
boolean bStop = false; //Stop identical u 1ZJHry  
FileAccessI fileAccessI = null; //File Access interface [?chK^8  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \sK:W|yy  
{ j z~[5m}J  
this.sURL = sURL; Gg%tVQu  
this.nStartPos = nStart; LJGJ|P  
this.nEndPos = nEnd; QjA&IZEC  
nThreadID = id; G02ox5X  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 99e*]')A%  
} X JY5@I.  
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public void run() 3Y z]8`C  
{ akT|Y4KxD  
while(nStartPos < nEndPos && !bStop) D_d|=
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{ *URdd,){i  
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try{ ?g2zmI!U  
URL url = new URL(sURL); Kax#OYLpg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wo{K}  
httpConnection.setRequestProperty("User-Agent","NetFox"); %3M95UZ2  
String sProperty = "bytes="+nStartPos+"-"; %>Bk
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httpConnection.setRequestProperty("RANGE",sProperty); {Eu'v$c!  
Utility.log(sProperty); k6@b|  
~r<p@k=.#0  
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InputStream input = httpConnection.getInputStream(); XaW4C-D&  
//logResponseHead(httpConnection); R2w`Y5#`  
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u_.HPA  
byte[] b = new byte[1024]; i\Yl  
int nRead; lEHwZ<je  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zPVd(V~(T  
{ =}v
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nStartPos += fileAccessI.write(b,0,nRead); 66Gx.tE  
//if(nThreadID == 1) lkA^\+
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vX+.e1m  
} ?Ko|dmX  
Seda}  
XJSa]P^B1  
Utility.log("Thread " + nThreadID + " is over!"); -`7$Qu2  
bDownOver = true; zDDK  
//nPos = fileAccessI.write (b,0,nRead); rB%y6P B  
} 3OP.12^  
catch(Exception e){e.printStackTrace ();} 0(gq;H5x'  
} ,r=re!QI7  
} aMTFW_w  
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t> . Fl-  
//打印回应的头信息 {.CMD9F[  
public void logResponseHead(HttpURLConnection con) +=eR%|!@  
{ ;`(R7X *3  
for(int i=1;;i++) Z\? E3j  
{ \Q&,ISO\  
String header=con.getHeaderFieldKey(i); U O<:.6"  
if(header!=null) m"d/b~q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #NNewzC<*  
Utility.log(header+" : "+con.getHeaderField(header)); j~`\XX{>  
else qZk:mlYd  
break; @r;wobt  
} S8vV!xO  
} 'bu)M1OLi  
3[IJhR[  
p &(OZJT  
public void splitterStop() v]"L]/"  
{ #=,imsW)  
bStop = true; sL^yB  
} U|@V 74  
{1-V]h.<J  
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} r&3pM2Da}  
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..W-76{  
/* kH948<fk3  
**FileAccess.java Di5(9]o2  
*//文件访问(定位，写) X~9j$3lUBR  
package NetFox; uJU*")\V  
import java.io.*; DcD{*t?x  
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public class FileAccessI implements Serializable{ aA'TD:&p1  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 b1#dz]  
RandomAccessFile oSavedFile; ]0V}D,V($  
long nPos; H^%lDz  
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public FileAccessI() throws IOException !YL..fb  
{ 0%Ll  
this("",0); -
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} \nNXxTxX!  
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public FileAccessI(String sName,long nPos) throws IOException N2r/ho}8  
{ v X~RP *  
oSavedFile = new RandomAccessFile(sName,"rw"); e}Vw!w  
this.nPos = nPos; +n0r0:z0  
oSavedFile.seek(nPos); 1$/MrPT(b  
} zET^T5>:  
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public synchronized int write(byte[] b,int nStart,int nLen) Rk<@?(l!6x  
{ jl.p'$Fbn  
int n = -1; )> ,wj  
try{ Y_&g="`Q  
oSavedFile.write(b,nStart,nLen); g,tjm(  
n = nLen; lz#GbXn.  
} - O98pi  
catch(IOException e) x5`br.b  
{ : JzI>/  
e.printStackTrace (); ,u }XWV  
} iXu]e;6  
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return n; S:4crI  
} Ee)[\Qjn  
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} YBYZ=,"d  
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/* q{s(.Uq$&  
**SiteInfoBean.java N8qDdr9p?c  
*/ bfB\h*XO  
package NetFox; S6}@I ,Q  
R1nJUOE4w^  
&PkLp4mQ  
public class SiteInfoBean { }I3gU  
b'VV'+|  
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private String sSiteURL; //Site's URL A7(hw~+@  
private String sFilePath; //Saved File's Path V.os  
private String sFileName; //Saved File's Name `cPywn@uGZ  
private int nSplitter; //Count of Splited Downloading File iXyO(w4D  
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public SiteInfoBean() G
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{//nSplitter的缺省值为5 jp $Z]  
//default value of nSplitter is 5 TKk-;Y=N  
this("","","",5); 4w#``UY)'  
} lKEkXO  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) m*$|GW9  
{ n}s~+USZX  
sSiteURL= sURL; k}KC/d9.z  
sFilePath = sPath; 9-]i.y  
sFileName = sName; =)hVn  
this.nSplitter = nSpiltter; Oy 2+b1{  
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} {EdH$l>94  
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public String getSSiteURL() u_7~TE3W  
{ w[6J `
 
return sSiteURL; ho>k$s?  
} xQw7 :18wQ  
G;f/Tch  
= waA`Id  
public void setSSiteURL(String value) RxMH!^  
{ 1 { , F
 
sSiteURL = value; p$ bnK]  
} lY*[tmz)  
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public String getSFilePath() 8p-=&cuo\@  
{ <L&m4O#|  
return sFilePath;  ^xPmlS;X  
} ZylJp
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public void setSFilePath(String value) W d0NT@  
{ C{2xHd/*  
sFilePath = value; ;;A2!w{}[i  
} fABe  
0zY(:;X  
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public String getSFileName() LL$_zK{  
{ <w\:<5e'  
return sFileName; S.!UPkWH  
} @|'5n  
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public void setSFileName(String value) ,.gQ^^+=  
{ wb Iq&>p  
sFileName = value; "`[!Lz
 
} =vT<EW}[  
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public int getNSplitter()
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{ y<C<_2  
return nSplitter; p\{-t84n  
} :iR \%  
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public void setNSplitter(int nCount)  lWm'  
{ 8>/Q1(q0  
nSplitter = nCount; 4d
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} e?bYjJq  
} m5G\}8|  
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/* :fk2]{KTL  
**Utility.java XBQ\_2>  
*/ fJZp?e"  
package NetFox; |#l=  
*)]"27^  
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public class Utility { jEXW  
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public Utility() R_sC!
-  
{ u9=SpgB#  
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} qW 1V85FG  
U}Hwto`R  
//线程睡眠 9
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public static void sleep(int nSecond) bN^O}[  
{ '2zL.:~  
try{ ^7]"kg DA  
Thread.sleep(nSecond); VE2tq k%  
} eK/?%t  
catch(Exception e) )x#5Il H  
{ /9yaW7w  
e.printStackTrace (); C}Ibx
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} >*twTlb{  
} acd:r%y  
t)oapIeIe  
//日志 4\.V  
public static void log(String sMsg) 52zGJ I*  
{ Y<\^7\[x  
System.err.println(sMsg); /W#O +  
} nRhrWS  
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public static void log(int sMsg) vtJV"h?e"3  
{ 8|twV35  
System.err.println(sMsg); )_zlrX  
} m8+(%>+
7  
} R4%P:qM  
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dEM?~?  
/* 2=PBxDs;  
**TestMethod.java Jeqxspn T  
*/ J3S&3+2G  
package NetFox; ;)DzCc/  
\o3"~\|6C  
~!%0Z9>ap  
public class TestMethod { t0PQ~|H<KV  
HW=xvA+  
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public TestMethod() rqCa 2  
{ ///xx/weblogic60b2_win.exe 4lc)&  
try{ 'Tb0-1S?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >Pe:I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }F`beoMAkM  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^>~dlS  
fileFetch.start(); t\j!K2  
} eNySJf  
catch(Exception e){e.printStackTrace ();} h\,5/ )Y  
nYv#4*  
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} D#sf i,O  
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public static void main(String[] args) Oo%!>!Lt,  
{ bLG]Wa  
new TestMethod(); {KaN,td9  
} +h[e0J|v{  
} ;?9A(q_Z  
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