http断点续传简单实现（java)

/* cu+FM  
**SiteFileFetch.java I!^O)4QRx  
*/ QY== GfHt  
package NetFox; Y3Q9=u*5  
import java.io.*; $ImrOf^qt  
import java.net.*; Y))NK'B5  
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public class SiteFileFetch extends Thread { 4*$G & TX  
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SiteInfoBean siteInfoBean = null; //文件信息Bean rx}r~0i  
long[] nStartPos; //开始位置 GgKEP,O  
long[] nEndPos; //结束位置 )p*}e8
L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .1LCXW=  
long nFileLength; //文件长度 $8BPlqBIZ  
boolean bFirst = true; //是否第一次取文件 i~r l o^  
boolean bStop = false; //停止标志 z;y:9l  
File tmpFile; //文件下载的临时信息 3po:xMY  
DataOutputStream output; //输出到文件的输出流 IsR!'%Pu  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Kv~U6_=1O  
public SiteFileFetch(SiteInfoBean bean) throws IOException XC+A_"w)  
{ S{3nM<  
siteInfoBean = bean; /&4U6a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); G}p\8Q}'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'F3)9&M  
if(tmpFile.exists ()) qgrg CJ  
{ V*~Zs'L'E  
bFirst = false; mkR2i>  
read_nPos(); #KO,~]k5|e  
} 2it?$8#i  
else 3h<,  
{ ]kboG%Dl?9  
nStartPos = new long[bean.getNSplitter()]; RD.V'`n"  
nEndPos = new long[bean.getNSplitter()];
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}  Tgl}  
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} TiH)5  
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public void run() k?7 X3/O  
{
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//获得文件长度 e
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//分割文件 IY*EA4>  
//实例FileSplitterFetch B-r0"MX&  
//启动FileSplitterFetch线程 M>/Zbnq  
//等待子线程返回 aCL!]4K84$  
try{ jq!tT%o*B  
if(bFirst) 4 uQT5  
{ YX#-nyK  
nFileLength = getFileSize(); I"`M@ %  
if(nFileLength == -1) 9VbOQ{8  
{ /J
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System.err.println("File Length is not known!"); zLJ/5&  
} y a_<^O 9  
else if(nFileLength == -2) 3g6j?yYqb  
{ ()H:UvM=t  
System.err.println("File is not access!"); Km^&<3ch#  
} '{B!6|"X  
else 5+wAzVA  
{ |ely|U. Tf  
for(int i=0;i<nStartPos.length;i++) vEn4L0D  
{ M4W5f#C5Ee  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jkvg
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} tzh1s i  
for(int i=0;i<nEndPos.length-1;i++) nb>7UN.9  
{ ,tg0L$qC  
nEndPos = nStartPos[i+1]; {+@bZ}57  
} ~_!F0
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nEndPos[nEndPos.length-1] = nFileLength;
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} o-Ga3i 8  
} ZR'H\Z  
i _%Q`i  
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//启动子线程 RG4sQ0
 
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; O &-wxJ]S  
for(int i=0;i<nStartPos.length;i++) ]H1I,`=@  
{ 9cj9SB4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %?Ev|:i`@  
nStartPos,nEndPos,i); ~T89_L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @qHNE,K  
fileSplitterFetch.start(); 6!(@@^7{*  
} Q0ON9gqqv  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,zTy?OQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (zFi$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", k Zq!&  
nEndPos = " + nFileLength); L5\WpM=  
// fileSplitterFetch[nPos.length-1].start(); eET}r24  
]S5JUAGkE*  
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//等待子线程结束 $81*^  
//int count = 0; )d>!"JB-  
//是否结束while循环 L:'J Bhg  
boolean breakWhile = false; 5hy""i  
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while(!bStop) 9\DQ>V TQ  
{ eh5gjSqx  
write_nPos(); 0p\@!Z H  
Utility.sleep(500); (/j); oSK  
breakWhile = true; W!&vul5  
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for(int i=0;i<nStartPos.length;i++) |x-S&-  
{ Mwr
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if(!fileSplitterFetch.bDownOver) .uk>QMs1  
{ 82DmG@"s2  
breakWhile = false; KkE9KwZ]W  
break; ;/rXQe1  
} I}vmU^Y>  
} !dC<4qZ\C  
if(breakWhile) x3"#POp  
break; }x wu*Zx  
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//count++; 1OF& *  
//if(count>4) E3iW-B8u8  
// siteStop(); 4BKI-;v$  
} \<)9?M
:  
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System.err.println("文件下载结束！"); M%0C_=zg  
} JQ@E>o7_  
catch(Exception e){e.printStackTrace ();} [YcG(^^  
} X]dwX%:Z!j  
!f+H,]D"  
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//获得文件长度 K]0JC/R6(@  
public long getFileSize() LmnymcH  
{ V:c;-)(  
int nFileLength = -1; "PpN0Rr  
try{ mA=i)Ga  
URL url = new URL(siteInfoBean.getSSiteURL()); Oal3rb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q{lpKe0  
httpConnection.setRequestProperty("User-Agent","NetFox"); z21|Dhiw&  
/Bm( `T  
#Q`dku%V:  
int responseCode=httpConnection.getResponseCode(); >b{q.  
if(responseCode>=400) %eO0wa$a  
{ .ODR]7{  
processErrorCode(responseCode); q*7VqB  
return -2; //-2 represent access is error c>)Yt^q&K  
} Aw5HF34J  
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?TKRjgW`@_  
String sHeader; yLQ*"sw\  
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for(int i=1;;i++) dKxyA"@  
{ _`:1M2=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); PU1Qsb5  
//Utility.log(in.readLine()); trp0V4b8  
sHeader=httpConnection.getHeaderFieldKey(i); [S>2ASj  
if(sHeader!=null) ~"k
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{ Ot6aRk  
if(sHeader.equals("Content-Length")) pv Gf\pu  
{  N#a$t&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); D5*q7A6  
break; `,(,t
n_  
} ZGKu>yM  
}  q;][5  
else :dQ B R  
break; G%W8S \  
} /Y7<5!cS  
} j4uvS!  
catch(IOException e){e.printStackTrace ();} --c"0,7  
catch(Exception e){e.printStackTrace ();} sv&;Y\2c  
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Utility.log(nFileLength); tE`u(B,  
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return nFileLength; u*ObwcI/Bn  
} u /\EtSH  
.G#8a1#  
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//保存下载信息（文件指针位置） O4V.11FnW  
private void write_nPos() KQg]0y d  
{ 9|gr0&#~j  
try{ 2h1vVF3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); t_$2CRG#  
output.writeInt(nStartPos.length); Pn>Xbe  
for(int i=0;i<nStartPos.length;i++) '
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{ r'HtZo$^R  
// output.writeLong(nPos); G#u6Am)T  
output.writeLong(fileSplitterFetch.nStartPos); e3nYbWBy]  
output.writeLong(fileSplitterFetch.nEndPos); !FElW`F  
} [k;\SXDZo  
output.close(); AN/;)wc  
} :lPb.UCY  
catch(IOException e){e.printStackTrace ();} n T{3o;A  
catch(Exception e){e.printStackTrace ();} Ne[7gxpu  
} < v@9#c  
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//读取保存的下载信息（文件指针位置） 'z%o16F)L  
private void read_nPos() YH\O
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{ )\J+Kiy)  
try{ pH"#8O&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \b?" b  
int nCount = input.readInt(); vnM@QfN  
nStartPos = new long[nCount]; P;qN(2L/=<  
nEndPos = new long[nCount]; q#,f 4P  
for(int i=0;i<nStartPos.length;i++)
7G}2,ueI  
{ ; Q3n
  
nStartPos = input.readLong(); 'kL#]  
nEndPos = input.readLong(); <~n"m  
} $JMXV  
input.close(); %&w3;d;c  
} Wp!%-vzy&  
catch(IOException e){e.printStackTrace ();} sP;nGQ.eN  
catch(Exception e){e.printStackTrace ();} NnDxq%l%  
} x:7b/j-  
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private void processErrorCode(int nErrorCode) !
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{ y}My.c  
System.err.println("Error Code : " + nErrorCode); 8o'_`{ba  
} :+z4~% jA  
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//停止文件下载 `Nb[G)Xh  
public void siteStop() I+[>I=ewa  
{ T>2[=J8U  
bStop = true; X[&Wkr8x '  
for(int i=0;i<nStartPos.length;i++) ymx>i~>7J  
fileSplitterFetch.splitterStop(); ,^w?6?,&l}  
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} zxbpEJzpn  
} 8&?s#5zA  
//负责部分文件的抓取 i]6`LqlO  
**FileSplitterFetch.java hRrn$BdLX  
*/ XINu=N(g  
package NetFox; ZjQ |Wx  
s'E2P[:  
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import java.io.*; 2.l Z:VLN  
import java.net.*; ^Eb.:}!D6  
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public class FileSplitterFetch extends Thread { | r&k48@  
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String sURL; //File URL BGD8w2  
long nStartPos; //File Snippet Start Position ]
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long nEndPos; //File Snippet End Position |"/8XA  
int nThreadID; //Thread's ID %_RQx2  
boolean bDownOver = false; //Downing is over D#il*  
boolean bStop = false; //Stop identical /H(? 2IHC  
FileAccessI fileAccessI = null; //File Access interface a!<8\vzg  
si
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52 fA/sx  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Crho=RJPR  
{ %|g>%D3Z?  
this.sURL = sURL; TDFkxB>  
this.nStartPos = nStart; #h8Sq~0  
this.nEndPos = nEnd; zF8dKFE~  
nThreadID = id; :Q $K<)[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7VqM$I  
} /%}*Xh  
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;#xmQi'`  
public void run() 6K-_pg]  
{ r@+ri1c  
while(nStartPos < nEndPos && !bStop) OWjk=u2Lz  
{ `e}b
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try{ 2Ga7$q  
URL url = new URL(sURL); hbzC#@q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \ 3wfwu.q  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7\$qFF-y  
String sProperty = "bytes="+nStartPos+"-"; 75"f2;  
httpConnection.setRequestProperty("RANGE",sProperty); -:2$ %  
Utility.log(sProperty); dJ2Hr;Lc  
>/kcdWl  
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InputStream input = httpConnection.getInputStream(); 7n8~K3~;  
//logResponseHead(httpConnection); _=Z,E.EN  
6*B19+-  
 [F0s!,P  
byte[] b = new byte[1024]; ~$:|VHl  
int nRead; &x[E;P*Fg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }!"A!~&  
{ P&9Gga^I  
nStartPos += fileAccessI.write(b,0,nRead); v 1z  
//if(nThreadID == 1) \K@'Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Cjqklb/  
} iop2L51eJ  
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Utility.log("Thread " + nThreadID + " is over!"); e+$p9k~  
bDownOver = true; +$C4\$t  
//nPos = fileAccessI.write (b,0,nRead); 8jd;JPz@\  
} P `}zlml  
catch(Exception e){e.printStackTrace ();} %QH)'GJQ  
} |Y$uqRdV  
} *)ardZV${  
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s}UjGFP  
//打印回应的头信息 UDL!43K  
public void logResponseHead(HttpURLConnection con) +Z7th7W/,  
{ hd>aZ"nm1  
for(int i=1;;i++) _/uFsYC  
{ K/tRe/t}  
String header=con.getHeaderFieldKey(i); 6-yd]("  
if(header!=null)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); WG N=Y~E  
Utility.log(header+" : "+con.getHeaderField(header)); d F9!G;V  
else !>{G,\^=pT  
break; TH; R  
} & -{DfNKc  
} ]h>_\9qO  
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public void splitterStop() QrB@cK]  
{ KM}f:_J*lg  
bStop = true; qfL~Wp2E;  
} Ge-CY  
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} aGJC1x  
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/* mQCeo}7N5  
**FileAccess.java WFO4gB*  
*//文件访问(定位，写) }4Tc  
package NetFox; YVYu:}e3)  
import java.io.*; $}J5xG,}$  
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public class FileAccessI implements Serializable{  {Or;  
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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 lJu;O/  
RandomAccessFile oSavedFile; J?RabYd ~  
long nPos; KNS.Nw7  
jX3,c%aQ5e  
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public FileAccessI() throws IOException (8Bk;bd  
{ x^kp^ /f  
this("",0); &xa(BX%,c  
} .q%WuQw  
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public FileAccessI(String sName,long nPos) throws IOException lV1G<qP  
{ :YXX8|>  
oSavedFile = new RandomAccessFile(sName,"rw"); AG!w4Ky`  
this.nPos = nPos; }\HN&@  
oSavedFile.seek(nPos); IPgt|if^  
} .QA }u ,EN  
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public synchronized int write(byte[] b,int nStart,int nLen) NWM8[dI  
{ V n*  
int n = -1; xnmmXtk  
try{ jp0<pw_  
oSavedFile.write(b,nStart,nLen); r30 <(nF  
n = nLen; S`#w+C#EW  
} -j73Wz  
catch(IOException e) G]+&!4  
{ k`0>36  
e.printStackTrace (); A%`[mc]4#  
} k\WR ]  
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return n; |&FkksNAl\  
} wQe_vY  
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} 2Ou[u#H  
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/* a"FCZ.O1  
**SiteInfoBean.java BReJ!|{m}  
*/ 4:|S` jm  
package NetFox; h{
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public class SiteInfoBean { 5[A@gw0u  
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private String sSiteURL; //Site's URL c- }X_)U }  
private String sFilePath; //Saved File's Path c17_2 @N  
private String sFileName; //Saved File's Name _tBTE%sO  
private int nSplitter; //Count of Splited Downloading File S<4c r  
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public SiteInfoBean() eu(:`uu  
{//nSplitter的缺省值为5 +tVaBhd!  
//default value of nSplitter is 5 So0f)`A  
this("","","",5); Cq'KoN%nQ  
} _>| =L W@7  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) DpUbzr41+k  
{ #7MUJY+ 9  
sSiteURL= sURL; KTP8?Q"n0  
sFilePath = sPath; "J4WzA%i  
sFileName = sName; Ed_N[I   
this.nSplitter = nSpiltter; hnDBFQ{  
[/Rf\T(,jn  
-F<Wd/Xse  
} ](&{:>RNJ  
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public String getSSiteURL() Q aS\(_  
{ G&4&-<  
return sSiteURL; sOU1n  
}  !"\80LP  
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public void setSSiteURL(String value) ]=>F.GE  
{ . koYHq  
sSiteURL = value; \'|>p/5I  
} mG
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;*:Pw?'  
public String getSFilePath() tE)suU5Y  
{ prTw'~(B  
return sFilePath; FLGk?.x$\  
} fpFhn  
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public void setSFilePath(String value) Bh;7C@dq  
{ @JyK|.b
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sFilePath = value; vSi.t
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} 5 N#3a0)  
)?X-(4  
v 8$>rwB  
public String getSFileName()
)i!o8YB  
{ YbTxn="_  
return sFileName; H;YP8MoQ  
} i*#-I3  
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public void setSFileName(String value) Tl2C^j  
{ a{ ?`t|  
sFileName = value; 4cl\^yD  
} 0@H|n^Md#  
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public int getNSplitter() F.w5S!5Q  
{ .HkL2m  
return nSplitter; ?TU}~}  
} t.`@{R$hoA  
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/.Ww6a~  
public void setNSplitter(int nCount) r[lF<2&*R  
{ E|6VX4`+  
nSplitter = nCount; aVK3?y2  
} D"ND+*Q[X  
} b\-&sM(W"  
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/* Xq
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**Utility.java Aq0S-HKF  
*/ >rJnayLF  
package NetFox; _Jme!Oaa  
}Rz3<eON  
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public class Utility { kH
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public Utility() y5do1Z  
{ n~A%q,DmF  
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{j:hod@-:5  
} W!?7D0q  
bpKZ3}U  
//线程睡眠 L"{JRbh[  
public static void sleep(int nSecond) Y6Lf@}2(i  
{ (fCXxyZrr  
try{ mo[Zb0>  
Thread.sleep(nSecond); ?sMP~RHQ  
} 6y6<JR-V2k  
catch(Exception e) ~:3QBMk::  
{ BPdfYu,il  
e.printStackTrace (); o[cV1G  
} LAd\Tvms  
} ,0hA'cp  
<-,gAk)u  
//日志 N(y\dL=v  
public static void log(String sMsg) q^r#F#*1l  
{ 89wU-Aggq  
System.err.println(sMsg); *T~Ve;3h;  
} ub;ZtsM,%  
8"fD`jtQ  
/XhIx\40l  
public static void log(int sMsg) =u+d_'P7-R  
{ 2UFv9  
System.err.println(sMsg); )e a:Q?  
} (Nx;0"5IX  
} h\PHKC2  
J,AR5@)1  
_c,'>aH=  
/* +=.W<b
 
**TestMethod.java `.x Fiyc  
*/ A@sZ14+f  
package NetFox; |m80]@>  
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public class TestMethod { `kU/NKq  
\U[{z&]~  
=9"W@n[>W  
public TestMethod() T)Y=zIQ1]7  
{ ///xx/weblogic60b2_win.exe j& <i&  
try{ 6Qx#%,U^ J  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8'f4 Od ?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); T`Mf]s)*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); JXu$ew>q  
fileFetch.start(); pGK;1gVj  
} &&VqD w  
catch(Exception e){e.printStackTrace ();} .]sf0S!  
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} U)o$WH.b  
U )l,'y2  
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public static void main(String[] args) Fm #w2o  
{ JM\m)RH0  
new TestMethod(); ^1L>l9F  
} ])Qs{hs~s  
} |"9 #bU  
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