http断点续传简单实现（java)

/* jHT^I as  
**SiteFileFetch.java rg[#(  
*/ ,]JIp~=nsh  
package NetFox; a'HHUii=  
import java.io.*; tol-PJS}  
import java.net.*; A]QGaWK  
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public class SiteFileFetch extends Thread { ]7,0>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )X*_oH=  
long[] nStartPos; //开始位置 Zd)LV
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long[] nEndPos; //结束位置 Q>X1 :Zn3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?gAwMP(>  
long nFileLength; //文件长度 c<q33dZ!*  
boolean bFirst = true; //是否第一次取文件 $pP
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boolean bStop = false; //停止标志 :Id8N~g  
File tmpFile; //文件下载的临时信息 {LKW%G7  
DataOutputStream output; //输出到文件的输出流 g|^U?|;p  
8:I-?z;S  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） XpKeN2=p  
public SiteFileFetch(SiteInfoBean bean) throws IOException u9q#L.Ij  
{ w=nS*Qy2  
siteInfoBean = bean; v8\_6}*I  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s 64@<oU<"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dJQwb
 
if(tmpFile.exists ()) :Eg4^,QX  
{ ,Cm1~ExJ  
bFirst = false; b H5lLcdf  
read_nPos(); 3# 0Nd"/0  
} Wl&6T1A`"  
else IWddJb~hu  
{ ze8MFz'm  
nStartPos = new long[bean.getNSplitter()]; 6ypHH 2X  
nEndPos = new long[bean.getNSplitter()]; Y!c7P,cZ+3  
} NeEV=+<-G  
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} >Wd=+$!I  
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public void run() K.?S,qg  
{ @v6{U?  
//获得文件长度 sx[mbKj<  
//分割文件 R6GlQ G
 
//实例FileSplitterFetch |ns9ziTDI  
//启动FileSplitterFetch线程 0x,4H30t(  
//等待子线程返回 HZ{DlH;&  
try{ apxq] ! `  
if(bFirst) &oVZ2.O#(  
{ Hnvs{KC`  
nFileLength = getFileSize(); >I/~)B`jhE  
if(nFileLength == -1) YpSK|(  
{ u]3VK  
System.err.println("File Length is not known!"); q"g4fzCD  
} DQN"85AIZ  
else if(nFileLength == -2) (iO/@iw  
{ RBeQT=B8~  
System.err.println("File is not access!"); u69G #  
} ?,Wm|x
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else LwI4 2  
{ !1+!;R@&H>  
for(int i=0;i<nStartPos.length;i++) 7c'OIY].,  
{ 5.Nc6$ N  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); C !
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} 59_VC('  
for(int i=0;i<nEndPos.length-1;i++) gEq";B%?  
{ @7Nc*-SM  
nEndPos = nStartPos[i+1]; Y-"7R>^I  
} v`"BXSmp{  
nEndPos[nEndPos.length-1] = nFileLength; !xC IvKW  
} AT^MQv
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} 4':U rJ+  
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//启动子线程 +oa>k 0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Bnd Y\  
for(int i=0;i<nStartPos.length;i++) $olITe"$g  
{ d a.6Z!a  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r}XsJ$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lJ4&kF=t  
nStartPos,nEndPos,i); ]K>x:vMKH  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9D& 22hL4  
fileSplitterFetch.start(); upF^k%<y:  
} &G!2T!xx  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b0Fr]oGp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l:"zYcp%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }mQh^  
nEndPos = " + nFileLength); l`<u\],  
// fileSplitterFetch[nPos.length-1].start(); /{\mV(F(  
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//等待子线程结束 I/w=!Ih  
//int count = 0; Z=/bD*\g  
//是否结束while循环 I
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boolean breakWhile = false; P'CDV3+  
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while(!bStop) )XL}u4X  
{ F$&{@hd  
write_nPos(); 08 aZU  
Utility.sleep(500); VZ$FTM^b8  
breakWhile = true; `Ot;KDz  
/M8&`  
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for(int i=0;i<nStartPos.length;i++) K9N\E"6ZP  
{ .UJjB}4$f  
if(!fileSplitterFetch.bDownOver) >c 5V VA8  
{ sAU!u  
breakWhile = false; ){{]3r  
break; Sg}]5Mn`  
} 3a]Omuu|=  
} /\1MG>#K  
if(breakWhile) mg7Q~SLL{  
break; =M+enSu  
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//count++; Qk.:b  
//if(count>4) V$XCe  
// siteStop(); C~aNOe WR  
} 5PU$D`7it  
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System.err.println("文件下载结束！"); $f^ \fa[  
} 4chSo.= 4V  
catch(Exception e){e.printStackTrace ();} "Gh?hU,WWZ  
} >B9|;,a  
]B"YW_.x2  
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//获得文件长度 _U`_;=(  
public long getFileSize() z rV  
{ $'2yPoR  
int nFileLength = -1; u.s-/ g  
try{ s!d"(K9E  
URL url = new URL(siteInfoBean.getSSiteURL()); ]M;aVw<!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !@x'?+
  
httpConnection.setRequestProperty("User-Agent","NetFox"); b8@gv OB  
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int responseCode=httpConnection.getResponseCode(); P|OjtI  
if(responseCode>=400) okO^/"  
{ SH/KC  
processErrorCode(responseCode); cH!w;Ub]  
return -2; //-2 represent access is error ag$mc8-p[  
} 7EKQE
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String sHeader; n^Qt !~  
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for(int i=1;;i++)
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9cu0$P`}5  
//Utility.log(in.readLine()); S"Dw8_y7}  
sHeader=httpConnection.getHeaderFieldKey(i); gt
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if(sHeader!=null) V+mTo^  
{ $Y!$I.+  
if(sHeader.equals("Content-Length")) X~O2!F  
{ 1{sfDw[s  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); gt9{u"o  
break; ;MqH)M  
} {/x["2a1  
} 5ap~;t  
else eJB !|  
break; YJlpP0;++  
} l0m\2Ttf  
} /\S1p3EW*  
catch(IOException e){e.printStackTrace ();} .CClc(bO_/  
catch(Exception e){e.printStackTrace ();} j7vp@l6`L  
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Utility.log(nFileLength); s:j"8ZH  

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return nFileLength; ,1"w2,=  
} 0k?ph$  
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//保存下载信息（文件指针位置） XCNfogl  
private void write_nPos() GT[,[l  
{ 5YlY=J  
try{ qV%t[>  
output = new DataOutputStream(new FileOutputStream(tmpFile)); NzmVQ-4  
output.writeInt(nStartPos.length); *RQkL'tRf  
for(int i=0;i<nStartPos.length;i++) l:O6`2Z  
{ :>U2yI  
// output.writeLong(nPos); N`tBDl"ld  
output.writeLong(fileSplitterFetch.nStartPos); 5} 9}4e  
output.writeLong(fileSplitterFetch.nEndPos); D:9/;9V  
} =(f+geA"hm  
output.close(); [b:$sR;  
} !%' 1x2?  
catch(IOException e){e.printStackTrace ();} ?j^[7  
catch(Exception e){e.printStackTrace ();} mJ=3faM  
} +?[,y  
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//读取保存的下载信息（文件指针位置） TO.71
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private void read_nPos() -9XB.)\#  
{ 03ol!|X"9  
try{ 6N}>@Y5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); D|W^PR:@h  
int nCount = input.readInt();
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nStartPos = new long[nCount];  >:whNp  
nEndPos = new long[nCount]; K-&&%Id6R  
for(int i=0;i<nStartPos.length;i++) M{U{iS  
{ <#U9ih 2  
nStartPos = input.readLong(); 3PB#m.N<  
nEndPos = input.readLong(); .z/M (  
} Ju""i4  
input.close(); \atztC{-L>  
} SF.4["$  
catch(IOException e){e.printStackTrace ();} j';V(ZY&BB  
catch(Exception e){e.printStackTrace ();} MS~c  $  
} bI)ItC_wf!  
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private void processErrorCode(int nErrorCode) cPh U qET  
{ xjHOrr OQ  
System.err.println("Error Code : " + nErrorCode); XeD9RMT  
} *Mf;  
}]1=?:tX%  
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//停止文件下载 +{V"a<D$m  
public void siteStop() Nf0'>`/  
{ (VYY-%N`  
bStop = true; \%nFCK0  
for(int i=0;i<nStartPos.length;i++) G=lcKtMdg  
fileSplitterFetch.splitterStop(); o9)pOwk7;  
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} }`g:)gJ  
} c}iVBN6~.<  
//负责部分文件的抓取 5Xn+cw*  
**FileSplitterFetch.java V[f-Nj Kf  
*/ x{Y}1+Y4  
package NetFox; <3dmY=  
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import java.io.*; vn"2"hPF|  
import java.net.*; ZMmaM "9  
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public class FileSplitterFetch extends Thread { 6QsH?!bu  
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String sURL; //File URL =5NrkCk#V  
long nStartPos; //File Snippet Start Position 1:<=zqh0  
long nEndPos; //File Snippet End Position /\L|F?+@  
int nThreadID; //Thread's ID ]3tg|?%B  
boolean bDownOver = false; //Downing is over ]M
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boolean bStop = false; //Stop identical o:kiIZ]  
FileAccessI fileAccessI = null; //File Access interface qms+s~oA  
-"qw5Y_oF?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %,$Ms?,n`  
{ h^klP:Q  
this.sURL = sURL; 5urM,1SQ@  
this.nStartPos = nStart; O)nLV~X  
this.nEndPos = nEnd; )3<|<jwcx  
nThreadID = id; >r%L=22+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Q3MG+@)S  
} 5Hvg%g-c  
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public void run() .<zW(PW  
{ ok;Yxp
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while(nStartPos < nEndPos && !bStop) K;jV"R<9  
{ hS]g^S==2h  
/(C?3}}L  
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try{ }ge~Nu>w  
URL url = new URL(sURL); 9{{QdN8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )i8Hdtn  
httpConnection.setRequestProperty("User-Agent","NetFox"); VU+
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String sProperty = "bytes="+nStartPos+"-"; 3`PPTG  
httpConnection.setRequestProperty("RANGE",sProperty); )1Rn;(j9Re  
Utility.log(sProperty); x)eYqH~i  
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InputStream input = httpConnection.getInputStream(); g_lj/u]P  
//logResponseHead(httpConnection); Oo'IeXQ9(  
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byte[] b = new byte[1024]; /BB(riG  
int nRead; o>rsk 6lNi  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) C Z8Fe$F  
{ +`pS 7d  
nStartPos += fileAccessI.write(b,0,nRead); 61|uvTX  
//if(nThreadID == 1) r|$@Wsb?#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :;[pl|}tM  
} j8p</gd  
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+a$'<GvP  
Utility.log("Thread " + nThreadID + " is over!"); [fF0Qa-  
bDownOver = true; 4]L5%=atn  
//nPos = fileAccessI.write (b,0,nRead); K)z{R n  
} *`~ woF  
catch(Exception e){e.printStackTrace ();} EBjSK
/  
} -2NXQ+m ;  
} ^(<Ecdz(  
@c&}\#;  
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//打印回应的头信息 VO#x+u]/  
public void logResponseHead(HttpURLConnection con) v{%x,K56  
{ U5X\RXy~  
for(int i=1;;i++) up+W[#+  
{ f681i(q"  
String header=con.getHeaderFieldKey(i); e>yPFXSk  
if(header!=null) 2'O2n]{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `Y HnL4  
Utility.log(header+" : "+con.getHeaderField(header)); Ore>j+  
else !cP2,l'f  
break; 32yGIR
V  
} eVL#3|=  
} T(LqR?xOo  
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#_]/Mr1  
public void splitterStop() &PY~m<F  
{ q18IqY*Lo  
bStop = true; +NML>g#F~z  
} `SDpOqfIrP  
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} a7?z{ssEi  
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/* ,4kly_$BH  
**FileAccess.java ckn0I  
*//文件访问(定位，写) L{;Sc_  
package NetFox; G]Rb{v,r  
import java.io.*; #cHH<09rl  
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public class FileAccessI implements Serializable{ MNC=r?  
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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 4:umD*d 3E  
RandomAccessFile oSavedFile; <x&0a$I  
long nPos; 12{F  
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public FileAccessI() throws IOException UA>3,|gV1  
{ GvAP  
this("",0); }kJfTsFS  
} o%EzK;Df  
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public FileAccessI(String sName,long nPos) throws IOException -DVoO2|Dv  
{ *}F>c3x]  
oSavedFile = new RandomAccessFile(sName,"rw"); #@pgB:~lB  
this.nPos = nPos; F747K);_  
oSavedFile.seek(nPos); RIC\f_Dv  
} I{bDa'rX  
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public synchronized int write(byte[] b,int nStart,int nLen) fnXYp !  
{ q fc:%ks2  
int n = -1; GG0H3MSc  
try{ `!Z0;qk  
oSavedFile.write(b,nStart,nLen); (M0"I1g|w  
n = nLen;
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} d
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catch(IOException e) xL&evG#  
{ %>p[;>jW  
e.printStackTrace (); 64LX[8Ax#  
} r5RUgt  
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return n; -R]Iu\  
} ^cUmLzM  
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} 6N49q-.Lg  
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cp:U@Nh(  
/* VGYx(  
**SiteInfoBean.java \DiAfx<Ub  
*/ cv{icz,%w  
package NetFox; @Ojbu@A  
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public class SiteInfoBean { -lY,lC>{  
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private String sSiteURL; //Site's URL >]L
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private String sFilePath; //Saved File's Path }>5R9  
private String sFileName; //Saved File's Name }ed{8"bj  
private int nSplitter; //Count of Splited Downloading File #0"Pd8@  
lC=-1*WH  
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public SiteInfoBean() 4<j7F4  
{//nSplitter的缺省值为5 2/iBk'd  
//default value of nSplitter is 5 &At9@  
this("","","",5); [;C|WTYSL  
} <Fi*
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) */APe#  
{ Al3*? H&  
sSiteURL= sURL; ,bxGd!&{Q  
sFilePath = sPath; >1qum'  
sFileName = sName; x MFo  
this.nSplitter = nSpiltter; ,rNv}  
0;L.h|R T(  
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} jK]An;l{
Z  
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public String getSSiteURL() S^x?<kYQau  
{ X%98k'h.y  
return sSiteURL; 35H.ZXQp-  
} ;d.gVR_V  
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public void setSSiteURL(String value) &X6hOc:``\  
{ +,_%9v?3  
sSiteURL = value; Gn%"B6  
} V6bjVd9|Z  
;LC?3.  
:CsrcT=  
public String getSFilePath() gle<{ `  
{ Mt*V-`+\  
return sFilePath; Yw6uh4  
} d/[kky}  
} 4ZWAzH  
q $=[v  
public void setSFilePath(String value) B"rO  
{ MJA;P7g  
sFilePath = value; P @~)9W  
}
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public String getSFileName() }J`cRDO  
{ Js&.p9S2  
return sFileName; -' =?Hs.  
} *mkVk7]c  
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s &f\gp1  
public void setSFileName(String value) oS~;>]W  
{ E"7[|-`e6  
sFileName = value; hOYP~OR  
} ovZ!}  
!j&#R%D  
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public int getNSplitter() q7p
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{ y@<&A~Cl^  
return nSplitter; x->+wJm@s  
} \x|8  
^mouWw)a_  
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public void setNSplitter(int nCount) @p@b6iLpO  
{ @SI,V8i  
nSplitter = nCount; rN,T}M=2  
} ]
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} i]Bu7Fuu  
5n[''#D  

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/* %a]Imsm  
**Utility.java et/v/Hvw1  
*/ /iL*)  
package NetFox; x.sC015Id  
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public class Utility { czsnPmNEI  
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public Utility() bq9/d4
  
{ ,YJn=9pTl  
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} vpC?JXz=H  
:? s{@7  
//线程睡眠 &Mz]y?k'  
public static void sleep(int nSecond) q7I!wD9Cff  
{ \Yn0|j
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try{ bz1AmNZ
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Thread.sleep(nSecond); <+<Nsza  
} RRQIlI<  
catch(Exception e) n}- _fx  
{ 8c>xgFWp9  
e.printStackTrace (); 2%*\XPt)  
} LnM$@  
} Zy.3yQM9i  
!,C8  
//日志 d%RH]j4  
public static void log(String sMsg) SM1L^M3)  
{ +"1-W>HV  
System.err.println(sMsg); h lSav?V_  
} ]u:_r)T  
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public static void log(int sMsg) :F9Oj1lM%  
{ 4P"XT  
System.err.println(sMsg); X<5&R{oZ  
} 3E0C$vKM  
} m4yWhUi(o  
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/* 3w"_Onwk  
**TestMethod.java .*X=[" F  
*/ J#q^CWN3R  
package NetFox; 1f'msy/  
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public class TestMethod { <;
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z:   
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public TestMethod() e{3%-  
{ ///xx/weblogic60b2_win.exe 4Xww(5?3
  
try{ - P"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]h=5d09z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t*dq*(3"c  
SiteFileFetch fileFetch = new SiteFileFetch(bean); sZ7~AJ  
fileFetch.start(); f0R+Mz8{  
} 6urU[t1  
catch(Exception e){e.printStackTrace ();} 9}L2$^#,NA  
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Z@%A(nZ_  
} mIPDF1=)  
id" l"  
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public static void main(String[] args) 2+b}FVOe\  
{ >YsM'.EFD  
new TestMethod(); lL 50PU  
} 2m} bddS  
} kP5G}Bp  
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