http断点续传简单实现（java)

/* 0s%{m<  
**SiteFileFetch.java +JFE\>O  
*/ _H2%6t/V  
package NetFox; 9[\$\l  
import java.io.*; Q S.w#"X[  
import java.net.*; ^w}BXVn  
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public class SiteFileFetch extends Thread { <m?/yREK2  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #J c)v0_  
long[] nStartPos; //开始位置 pB]+c%\  
long[] nEndPos; //结束位置 -+|{#cz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 '%A*Z,f  
long nFileLength; //文件长度 V)r6bb{^  
boolean bFirst = true; //是否第一次取文件  %?:eURQ  
boolean bStop = false; //停止标志 =g^JJpS  
File tmpFile; //文件下载的临时信息 {B6tGLt#bf  
DataOutputStream output; //输出到文件的输出流 `OyYo^+D|.  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Q(YQ$i"S  
public SiteFileFetch(SiteInfoBean bean) throws IOException 2Yd;#i)  
{ {{4Sgb  
siteInfoBean = bean; {W#VUB  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #]o#~:S=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Jro%zZle  
if(tmpFile.exists ()) -u'BK@;
  
{ V IU4QEW`x  
bFirst = false; )eSD5hOI)  
read_nPos(); .3T#:Hl  
} tJY3k$YX  
else lMBXD?,,J  
{ _NJq%-,'  
nStartPos = new long[bean.getNSplitter()]; . !;K5U  
nEndPos = new long[bean.getNSplitter()]; !"x&tF  
} +~\c1|f  
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} nqyB,vv0  
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public void run()
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{ 2r&T.  
//获得文件长度 ;v1&Rs  
//分割文件
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//实例FileSplitterFetch |;_uN q9  
//启动FileSplitterFetch线程 okZDxg`6  
//等待子线程返回 6o/!H  
try{ dg]: JU  
if(bFirst) rYMHc@a9(  
{ +gOv5Eno-  
nFileLength = getFileSize(); :CAbGs:56  
if(nFileLength == -1) ep2#a#&'  
{ t<2B3&o1  
System.err.println("File Length is not known!"); eE-@dU?  
} $]yHk  
else if(nFileLength == -2) #!X4\+)  
{ }EZd=_kAq~  
System.err.println("File is not access!"); 9nPc>O$  
} ^.@BD4/RPt  
else hzjEO2  
{ 2aUy1*aM  
for(int i=0;i<nStartPos.length;i++) YAf`Fnmw  
{ x7]Yn'^'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &*#- %<=1  
} ! uyC$8V*l  
for(int i=0;i<nEndPos.length-1;i++) AGxG*KuZ  
{ #2023Zo]  
nEndPos = nStartPos[i+1]; wfxg@<WR  
} Z>H y+Q4  
nEndPos[nEndPos.length-1] = nFileLength; dLMKfh/4Q  
} 2,X~a;+  
} eD481r  
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}XiV$[xHd  
//启动子线程 .UuCTH;6`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; u/BCl!`  
for(int i=0;i<nStartPos.length;i++) }vbs6u  
{ hs"=>(P)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o4"7i 9+g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), sSMcF[]@2I  
nStartPos,nEndPos,i); }QL 2#R  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8&"@6/)[  
fileSplitterFetch.start(); WU -_Y^  
} 75LIQ!G|=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /i#~#Bn|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); f|f9[h'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |h; _r&  
nEndPos = " + nFileLength); 67/&.d!  
// fileSplitterFetch[nPos.length-1].start(); g= ql 3N  
!V6O~#  
DhwFD8tT  
//等待子线程结束 <QyJJQM  
//int count = 0; :!h1S`wS  
//是否结束while循环 ;9r`P_r  
boolean breakWhile = false; aD1G\*AFJ  
0OndSa,  
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while(!bStop) y%21`y&Os  
{ +d0&(b  
write_nPos(); &ESE?{of)  
Utility.sleep(500); ^nYS@  
breakWhile = true; G02(dj  
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for(int i=0;i<nStartPos.length;i++) s\6kXR  
{ ]F5qXF5  
if(!fileSplitterFetch.bDownOver) q#$4Kt;  
{ 3:f<cy   
breakWhile = false; 3JiJ,<,7  
break; ~@x@uY$5  
}
%8)GuxG*  
} tTT./-*0  
if(breakWhile) )pS1yYLj  
break; 4|ryt4B  
=#AeOqs( q  
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//count++; P| o_/BS  
//if(count>4) Lzzf`jN]  
// siteStop(); ;hz"`{(JY  
} m/)Wn  
}vRs n-E@  
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System.err.println("文件下载结束！"); xHv<pza:  
} 'J (4arN  
catch(Exception e){e.printStackTrace ();} jJc?/1jv  
} HG2i^y  
=y; tOdj
  
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//获得文件长度 VuDS
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public long getFileSize() Kf<-PA  
{ X&1R6O  
int nFileLength = -1; -'FzH?q:  
try{ .u3!%{/v(c  
URL url = new URL(siteInfoBean.getSSiteURL()); wz-9+VN6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0f
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httpConnection.setRequestProperty("User-Agent","NetFox"); OXy>Tlv  
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int responseCode=httpConnection.getResponseCode(); ;?>xuC$  
if(responseCode>=400) +1j@n.)ft  
{ [-)N}rL>  
processErrorCode(responseCode); (Yz EsY  
return -2; //-2 represent access is error `p@YV(  
} ~yH<,e  
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String sHeader; 3%?01$k  
%(GWR@mfC  
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for(int i=1;;i++) ?lJm}0>  
{ - Dm/7Sxd`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7q>WO  
//Utility.log(in.readLine()); HhN;&67~Z  
sHeader=httpConnection.getHeaderFieldKey(i); .'md `@t  
if(sHeader!=null) p/|]])2  
{ ozZW7dveU  
if(sHeader.equals("Content-Length")) $=7[.z&  
{ / AFn8=9'^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 58"Cn ||tF  
break; ]de'v  
} e"u=4nk  
} WQ/H8rOs  
else {=WTAgP  
break; &?m|PK)I
 
} 9NTBdo%u  
} COe"te  
catch(IOException e){e.printStackTrace ();} C%ibIcm y  
catch(Exception e){e.printStackTrace ();} Az29?|e  
5?+ECxPt  
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Utility.log(nFileLength); h:iK;  
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return nFileLength; vA rM.Bu>b  
} jm1f,=R  
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8_8r{a<xW  
//保存下载信息（文件指针位置） 8X":,s!  
private void write_nPos() ;Wa4d`K  
{ xSFY8  
try{ VG*Tdaua~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); C~PrIM?  
output.writeInt(nStartPos.length); lf4V;|!^  
for(int i=0;i<nStartPos.length;i++) 4,CQJ  
{ w]b3,b  
// output.writeLong(nPos); ~1&%,$fZ  
output.writeLong(fileSplitterFetch.nStartPos); 1|)l6#hOL  
output.writeLong(fileSplitterFetch.nEndPos); m6J7)Wp  
} &kKopJH  
output.close(); >U\,(VB  
} ^&oa\7<'  
catch(IOException e){e.printStackTrace ();} |Q
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catch(Exception e){e.printStackTrace ();} cd1M0z  
} +}H2|vP  
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//读取保存的下载信息（文件指针位置） hGmJG,H  
private void read_nPos() XXsN)2  
{ *-~B{2b<  
try{ aIV(&7KT4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 07WZ w1(;  
int nCount = input.readInt(); a+!#cQl  
nStartPos = new long[nCount]; x/*ndH  
nEndPos = new long[nCount]; T|o[! @:,  
for(int i=0;i<nStartPos.length;i++) +b_g,RNs!  
{ 7=yC*]BH-=  
nStartPos = input.readLong(); @/i;/$\
 
nEndPos = input.readLong(); %N 8/g]`7  
} 
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input.close(); o<@b]ukl&  
} #L[-WC]1y  
catch(IOException e){e.printStackTrace ();} 0PIiG-o9  
catch(Exception e){e.printStackTrace ();} f`w$KVZ1!w  
} EgO=7?(pW  
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private void processErrorCode(int nErrorCode) e;KZTH;  
{ s[h& Uv"G  
System.err.println("Error Code : " + nErrorCode); F(*~[*Ff  
} 9U1cH qV  
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*sI`+4h[  
//停止文件下载 5~Vra@iab:  
public void siteStop() 0{bGVLp  
{ ssVO+ T  
bStop = true; Qhlgu
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for(int i=0;i<nStartPos.length;i++) ,L ;ueAo  
fileSplitterFetch.splitterStop(); 'V";"Ei  
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} xE(VyyR  
} q{/>hvl  
//负责部分文件的抓取 v'Y)~Kv@!  
**FileSplitterFetch.java pE{ZWW[@+  
*/ ,H!E :k  
package NetFox; L~N<<8?\   
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import java.io.*; t}LV[bj1u  
import java.net.*; 2\h]*x%:  
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public class FileSplitterFetch extends Thread { )-$Od2u2c  
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String sURL; //File URL GtcY){7  
long nStartPos; //File Snippet Start Position VfAC&3%M
 
long nEndPos; //File Snippet End Position r )8[LN-  
int nThreadID; //Thread's ID `I+G7KK  
boolean bDownOver = false; //Downing is over 3=w$1.B d  
boolean bStop = false; //Stop identical vZj:\geV  
FileAccessI fileAccessI = null; //File Access interface 'PW~4f/m  
(S/f!Dk&3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException NoS|lT  
{ g.yr) LHt0  
this.sURL = sURL; K3jKOV8  
this.nStartPos = nStart; ] h3~>8<  
this.nEndPos = nEnd; ,$irJz F  
nThreadID = id; rlSar$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 
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} b4`t, D  
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public void run() H8d%_jCr  
{ n}?XFx!%  
while(nStartPos < nEndPos && !bStop) ~"eos~AuW  
{ ZMO7o 1"  
 qW8sJ=  
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try{  ^2-2Jz@  
URL url = new URL(sURL); 5~&9/ALk5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 61e)SIRz9I  
httpConnection.setRequestProperty("User-Agent","NetFox"); PCzC8~t  
String sProperty = "bytes="+nStartPos+"-"; [DS.@97n  
httpConnection.setRequestProperty("RANGE",sProperty); * SH5p  
Utility.log(sProperty); Ua^#.K  
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InputStream input = httpConnection.getInputStream(); qN h:;`  
//logResponseHead(httpConnection); },9Hq~TA  
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byte[] b = new byte[1024]; pR6mSfer  
int nRead; 9?"]dEM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) " `rkp=  
{ Q)eYJP=W  
nStartPos += fileAccessI.write(b,0,nRead); 'p3JYRT$  
//if(nThreadID == 1) R5M/Ho 4
 
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $X1T!i[.X  
} 8Jnb/A}  
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9  
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Utility.log("Thread " + nThreadID + " is over!"); ];& @T\Rj  
bDownOver = true; yhzC 9nTH  
//nPos = fileAccessI.write (b,0,nRead); .U.Knn  
} &''lOS|  
catch(Exception e){e.printStackTrace ();} (tQ#('(w  
} "G. L)oD  
} 9[yW&t;#  
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s;!TB6b@  
//打印回应的头信息 ' S%?&4  
public void logResponseHead(HttpURLConnection con) %M"rc4Xd  
{ V$U#'G>m  
for(int i=1;;i++) om6'%nXhn  
{ A")F7F31c  
String header=con.getHeaderFieldKey(i); W"j&':xD  
if(header!=null) JC|j*x(k/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); wrw4Uxq  
Utility.log(header+" : "+con.getHeaderField(header)); +T]/4"^M  
else M7U:UV)  
break; BYjEo  
} | Q0Wv8/  
} qffVF|7  
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#mhR^60,  
public void splitterStop() 7lQ@I}i  
{ NDsF<2A4  
bStop = true; X2CpA;#;7l  
} ~mAv)JK  
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} A HnXN%m  
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/* 0hJ,l.  
**FileAccess.java N %;bV@A9  
*//文件访问(定位，写) 44e
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package NetFox; sa8Q1i&%  
import java.io.*; .%~m|t+Rt  
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public class FileAccessI implements Serializable{ ScN'|Ia.-  
&lnr?y^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 jtS-nQ|  
RandomAccessFile oSavedFile; rQE:rVKVh  
long nPos; -zn$h$N4  
SSCyq#dl$  
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public FileAccessI() throws IOException @\ udaZc  
{ _JEe]  
this("",0); -@=As00Bg  
} _]oNbcbt(  
{,:yZ&(  
= Ob-'Syg>  
public FileAccessI(String sName,long nPos) throws IOException `i~kW  
{ o8uak*"{  
oSavedFile = new RandomAccessFile(sName,"rw"); iX]tL:,~i  
this.nPos = nPos; LN=6u  
oSavedFile.seek(nPos); *;E\,,Io  
} 8.`*O  
},eV?eGj  
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public synchronized int write(byte[] b,int nStart,int nLen) _
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{ :v$][jZ2  
int n = -1; nF"NXYa  
try{ qcVmt1"
 
oSavedFile.write(b,nStart,nLen); ;RR\ Hwix  
n = nLen; $p(  
} K9\r2w'T'  
catch(IOException e) >`E (K X  
{ &9j*Y  
e.printStackTrace (); g \;,NW^  
} SN#Cnu}  
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return n; J 2H$ALl  
} a_
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} |K.J@zW  
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/* =Z 
/*  
**SiteInfoBean.java Nflw
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*/ E'g?44vyw  
package NetFox; .DrGr:UW  
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public class SiteInfoBean { 6<t<hP_3O  
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Q8h0:Q  
private String sSiteURL; //Site's URL q1Sr#h|  
private String sFilePath; //Saved File's Path dy"7Wl]hi7  
private String sFileName; //Saved File's Name 9z'(4U  
private int nSplitter; //Count of Splited Downloading File F2)\%HR  
52P^0<Wq  
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public SiteInfoBean() yd=NafPM  
{//nSplitter的缺省值为5 ]39])ul  
//default value of nSplitter is 5 <^n@q f}  
this("","","",5); wn Q% 'Eo  
} *KYh_i  
uY;7&Lw y1  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) cgV5{|P  
{ 1lLXu  
sSiteURL= sURL; -IE=?23Do?  
sFilePath = sPath; "2_nN]%u-  
sFileName = sName; %|(Cb!ySX  
this.nSplitter = nSpiltter; =38
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wl Nl|+ K  
b O9PpOk+z  
} O*lMIWx  
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public String getSSiteURL() F9J9zs*,  
{ 0c GjOl  
return sSiteURL; cv7.=*Kb;  
} rD!UP1Nb  
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public void setSSiteURL(String value) Iy;bzHXs  
{ |'QgL0?  
sSiteURL = value; DR<=C`<4(  
} Hd ${I",  
k vF[d{l
 
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public String getSFilePath() 0RF<:9@x2  
{ fO{'$?K  
return sFilePath; 82P#C4c+d  
} $_+.D`vx`  
O_P8OA#|  
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public void setSFilePath(String value) QI4a@WB]ok  
{ NOQSLT=  
sFilePath = value; 2PViY,V|  
} [&5%$ T  
{(5M)|>  

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public String getSFileName() 83pXj=k<  
{ |IZ
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return sFileName; um=qT)/D  
} |>dqZ_)v  
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public void setSFileName(String value) ia*Bcx_RW+  
{ +i(;@
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sFileName = value; +kM*BCPYE  
} OE(!^"5?[  
."h>I @MH  
`{+aJ0<S  
public int getNSplitter() >U62vX"  
{ qlg?'l$03)  
return nSplitter; ,3bAlc8D7  
} qwvch^?>FQ  
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public void setNSplitter(int nCount) s-e<&*D[  
{ VI;)VJbq  
nSplitter = nCount; >mp"=Y  
}
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} G]E-2 _t7  
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/* q/dja  
**Utility.java m<GJ1)%3i  
*/ OcZ8:`=%  
package NetFox; deqL  
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public class Utility { - %`iLu  
*:,y`!F=y  
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public Utility() q:3HU<  
{ ,7^,\ ,-m  
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} ct@i]}"`  
,_U3p ,  
//线程睡眠 A>Xt 5vk+  
public static void sleep(int nSecond) >OW>^%\!1  
{
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try{ 11BfJvs:  
Thread.sleep(nSecond); oWcBQ|   
} ;0Mg\~T~'  
catch(Exception e) > m##JzWLr  
{ NSDls@m  
e.printStackTrace (); l3;MjNB^V  
} ky{-NrK  
} DtOL=m]s  
w<G'gi]  
//日志 3vRBK?Q.y  
public static void log(String sMsg) t'DYT"3  
{ rRd8W}B  
System.err.println(sMsg); ['\u?m  
} P
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r|JZU  
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public static void log(int sMsg) BV512+M  
{ b(?A^a  
System.err.println(sMsg); +I_p\/J?w/  
} S#f}mb0,  
} 8L,i}hIo.  
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/* U=>4=gsG  
**TestMethod.java Z*M-PaU}  
*/ sI#r3:?i  
package NetFox; TptXH?  
="AJ&BqHd  
pb=yQ}.  
public class TestMethod { MP%pEUomev  
07qL@![!  
W6L}T,epX  
public TestMethod() [y1 x`WOk9  
{ ///xx/weblogic60b2_win.exe _%6Vcy  
try{ d ~3GEK  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N Uq'96{Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _do(   
SiteFileFetch fileFetch = new SiteFileFetch(bean); <s(<ax30  
fileFetch.start(); 2kQa3Pan  
} ;sfk@ec  
catch(Exception e){e.printStackTrace ();} @Yy']!Ju  
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} u<a =TPAU  
}5a$Ka-  
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public static void main(String[] args) >2@ a\  
{ iJem9XXb  
new TestMethod(); $][$ e  
} Q2HULz{
 
} {ZrB,yK  
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