http断点续传简单实现（java)

/* _64<[2  
**SiteFileFetch.java JVq`v#8  
*/ hO..
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package NetFox; JTdcLmL  
import java.io.*; #|;;>YnZ  
import java.net.*; ,%$Cfu  
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public class SiteFileFetch extends Thread { /[=U$=uH  
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SiteInfoBean siteInfoBean = null; //文件信息Bean b
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long[] nStartPos; //开始位置 f (ug3(j  
long[] nEndPos; //结束位置 yPT\9"/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 U~_G *0  
long nFileLength; //文件长度 ](SqLTB+?  
boolean bFirst = true; //是否第一次取文件 of0hJR  
boolean bStop = false; //停止标志 Ep8 y  
File tmpFile; //文件下载的临时信息 }080=E  
DataOutputStream output; //输出到文件的输出流 ;;<[_gp,E  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #r;uM+  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~RIa),GVX  
{ mmBZ}V+&=  
siteInfoBean = bean; Ahrtl6@AS  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "Tc[1{
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1j\wvPLr  
if(tmpFile.exists ()) _[8sL^  
{ XDAwE  
bFirst = false; h f9yK6  
read_nPos(); zZI7p[A[3  
} &~sk7iGi  
else A]AM|2
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{  Sn-D|Z  
nStartPos = new long[bean.getNSplitter()]; (5&l<u"K~  
nEndPos = new long[bean.getNSplitter()]; <7yn:  
} VIg=|Oe),  
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} C^!ej"  
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public void run() 31n|ScXv  
{ Z'|A>4\  
//获得文件长度 {#J1D*?
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//分割文件 W.VyH|?  
//实例FileSplitterFetch aIABx!83>  
//启动FileSplitterFetch线程 {GM8}M~D&  
//等待子线程返回 1PdxoRa4=  
try{ G?QU|<mj<  
if(bFirst) &4-rDR,  
{ AC9#!# OGB  
nFileLength = getFileSize(); {uuvgFC  
if(nFileLength == -1) @dp1bkU  
{ =| M[JPr  
System.err.println("File Length is not known!"); b1`(f"&l  
} 1O]27"9  
else if(nFileLength == -2) (Jb[_d*  
{ Z,bvD'u  
System.err.println("File is not access!"); mQ]wLPP{1  
} Q8
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else ljo^ 2  
{ ,0R2k `m!  
for(int i=0;i<nStartPos.length;i++) Ood'kAH1B  
{ qg;fh]j%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ET7(n0*P}]  
} HN*w(bROr  
for(int i=0;i<nEndPos.length-1;i++) K?o}B  
{ d.3O1TXK  
nEndPos = nStartPos[i+1]; jW-j+WGSM  
} T8i9  
nEndPos[nEndPos.length-1] = nFileLength; (]mh}=:KDg  
} i-EFq@xl  
} Sr`gQ#b@r}  
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[[PUK{P0  
//启动子线程 RJ_ratKN*g  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Gd~Xvw,u  
for(int i=0;i<nStartPos.length;i++) $3!j1  
{ 61Nj&1Ze  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7FVu[Qu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }V3p <  
nStartPos,nEndPos,i); \"qXlTQ1_9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?zKVXK7}0  
fileSplitterFetch.start(); rSD!u0c[  
} _gY so]S^B  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -P5VE0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Z3G>DF:$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }B_n}<tjD  
nEndPos = " + nFileLength); '!!w|kd  
// fileSplitterFetch[nPos.length-1].start(); EvMhNq~y5  
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`OnN12`  
//等待子线程结束 ehXj.z  
//int count = 0; LS?hb)7  
//是否结束while循环 w?.0r6j  
boolean breakWhile = false; HB\y [:E  
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while(!bStop) {t[j>_MYw  
{ ]?^m;~MQZ  
write_nPos(); K2L+tw  
Utility.sleep(500); [S":~3^B6  
breakWhile = true; [Y*p I&f  
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/
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for(int i=0;i<nStartPos.length;i++) ^MUtmzh  
{ g`gH]W FcG  
if(!fileSplitterFetch.bDownOver) b}o^ ?NtA  
{ @y9_\mX!s  
breakWhile = false; x!MYIaZ7  
break; " 9 h]P^  
} hp,bfcM  
} 3Zdkf]Gh  
if(breakWhile) 2@1A,  
break; //>f#8Ho  
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//count++; 2>.B*P  
//if(count>4) +l2{EiQw  
// siteStop(); D+N{'d?+  
} yFshV\  
a*NcL(OC  
}X)mZyM[  
System.err.println("文件下载结束！"); 7:R8QS9  
} =5oE|F%  
catch(Exception e){e.printStackTrace ();} Q~#udEajI  
} tV9nC  
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=\ iV=1iB  
//获得文件长度 xYRN~nr  
public long getFileSize() cMsm[D{b  
{ u8v;O}#  
int nFileLength = -1; TPt<(-}W  
try{ lDnF(  
URL url = new URL(siteInfoBean.getSSiteURL()); >>Z.]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "e0$/WQ6J  
httpConnection.setRequestProperty("User-Agent","NetFox"); i!LEA/"V  
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int responseCode=httpConnection.getResponseCode(); `6)GjZh^  
if(responseCode>=400) .EM0R\q  
{ t4/d1qW0  
processErrorCode(responseCode); oa?bOm  
return -2; //-2 represent access is error HJo&
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} fr#Y<=Jo  
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String sHeader; 5 >S#ew  
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for(int i=1;;i++) -~\R.<+
 
{ gHpA@jdC*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :W6`{
Z  
//Utility.log(in.readLine()); 8/F}vfKEN  
sHeader=httpConnection.getHeaderFieldKey(i); cVYDO*N2T  
if(sHeader!=null) Tw*:Vw  
{ Q>Voa&tYn  
if(sHeader.equals("Content-Length")) ?~X*\  
{ bnHQvCO3$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V

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break; (8T36pt~  
} <qJI]P  
} E-gI'qG\(  
else J<hqF4z  
break; H@Yj  
} omz%:'m`~  
} .TZ0FxW  
catch(IOException e){e.printStackTrace ();} hWc`4xdl  
catch(Exception e){e.printStackTrace ();} H4RqOI  
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Utility.log(nFileLength); )(bAi  
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return nFileLength; zplAH!s5''  
} &[ oW"Q{  
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//保存下载信息（文件指针位置） !m]_tB  
private void write_nPos() i ZU1w7Z  
{ j(aok5:e  
try{ d23;c )'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S?Y%
}  
output.writeInt(nStartPos.length); ,I|3.4z  
for(int i=0;i<nStartPos.length;i++) 9U]3B)h%m  
{ cG)U01/"  
// output.writeLong(nPos);  " fXs
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output.writeLong(fileSplitterFetch.nStartPos); !)r1zSY"g  
output.writeLong(fileSplitterFetch.nEndPos); xaN[ru@  
} e^=b#!}-5:  
output.close(); c`Q#4e]%_  
} Z Jgy!)1n  
catch(IOException e){e.printStackTrace ();} aM5Hp>'nI  
catch(Exception e){e.printStackTrace ();} \+Nn>wW.  
} F+<e9[  

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//读取保存的下载信息（文件指针位置） <D`VFSEJ  
private void read_nPos() OC6v%@xa  
{ 1xTNrLW  
try{ )z\ 73|w  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ooA%/  
int nCount = input.readInt(); bZ SaL^^(  
nStartPos = new long[nCount]; ?Gnx!3Q  
nEndPos = new long[nCount]; $y_P14   
for(int i=0;i<nStartPos.length;i++) \=2<< iv  
{ wiP )"g.t  
nStartPos = input.readLong(); =/m$ayG  
nEndPos = input.readLong(); ]KM3G  
} ':d9FzGKa  
input.close(); (zml704dI)  
} F\2<q$Zn+  
catch(IOException e){e.printStackTrace ();} *@eZt*_  
catch(Exception e){e.printStackTrace ();} rI#,FZ  
} jaL#  
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private void processErrorCode(int nErrorCode) KY+BXGW*  
{ M@=VIrX,m  
System.err.println("Error Code : " + nErrorCode); "IJ 9vXI  
} PTH'-G  
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//停止文件下载 FO:k >F  
public void siteStop() =JE5/  
{ B8 r#o=q1  
bStop = true; [5-3PuT&9  
for(int i=0;i<nStartPos.length;i++) Z#zXary5s  
fileSplitterFetch.splitterStop(); AP9>_0=  
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)
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} AvcN,  
} a{\<L/\  
//负责部分文件的抓取 O4oI&i 7  
**FileSplitterFetch.java ,HwOMoP7  
*/ }K|40oO5  
package NetFox; }8dS[-.  
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 zt2#6v  
import java.io.*; !"SuE)WM  
import java.net.*; 5GwzG<.\^_  
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public class FileSplitterFetch extends Thread { UF;iw  
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String sURL; //File URL vt(cC))  
long nStartPos; //File Snippet Start Position )|B3TjHC  
long nEndPos; //File Snippet End Position ~y>NJM>1  
int nThreadID; //Thread's ID ok/{ w  
boolean bDownOver = false; //Downing is over Fjw+D1q.  
boolean bStop = false; //Stop identical "f4atuuXa  
FileAccessI fileAccessI = null; //File Access interface Jj7he(!_1  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException RP%7M8V){B  
{ c}mWAZ=wF  
this.sURL = sURL; li&
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this.nStartPos = nStart; ?y2v?h"  
this.nEndPos = nEnd; o,_R;'\E[a  
nThreadID = id; _e$T'*q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5^C.}/#>F  
} ;fZ9:WB  
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public void run() Ax'o|RE)x  
{ 6Jd.Eg ~A7  
while(nStartPos < nEndPos && !bStop) =v7%IRP5  
{ Itv}TK eF  
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try{ 5'S~PQka*  
URL url = new URL(sURL); */y (~O6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VTJxVYE  
httpConnection.setRequestProperty("User-Agent","NetFox"); i]}`e>fF  
String sProperty = "bytes="+nStartPos+"-"; i2 G.<(3O  
httpConnection.setRequestProperty("RANGE",sProperty); FwqaWEk  
Utility.log(sProperty); evGUl~</~  
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InputStream input = httpConnection.getInputStream(); Ms14]M[\  
//logResponseHead(httpConnection); 2dnyIgi  
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byte[] b = new byte[1024]; cc{^0JT  
int nRead; vY!'@W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) pd}Cg'}X  
{ s_%KWkS  
nStartPos += fileAccessI.write(b,0,nRead); +AYB0`X)  
//if(nThreadID == 1) 4}Dfi5:   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zy'cf5k2  
} 4^_'LiX3[  
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Utility.log("Thread " + nThreadID + " is over!"); {3eg4j.Z  
bDownOver = true; ]i Yp  
//nPos = fileAccessI.write (b,0,nRead); A^vvw~!d
 
} [^0 S
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catch(Exception e){e.printStackTrace ();} T_Cj=>L  
} SSysOeD+  
} Qm>2,={h  
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//打印回应的头信息 ;|pw;-  
public void logResponseHead(HttpURLConnection con) 8 DPn5E#M1  
{ @7`=0;g  
for(int i=1;;i++) U# U*^#  
{ U?=-V8#M|  
String header=con.getHeaderFieldKey(i); +d=w%r)  
if(header!=null) fVz0H1\J&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #j4RX:T*[  
Utility.log(header+" : "+con.getHeaderField(header)); S
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else  w\y)  
break; b=XXp`h~a  
} 65U&P5W  
} m
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@ RP?)*8}&  
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public void splitterStop() 7gE/g`"#  
{ 3jjV bm  
bStop = true; .4[M7)  
} [F+*e=wjN>  
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} X#Hl<d2  
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/* !q 9PO  
**FileAccess.java 7M<co,"  
*//文件访问(定位，写) $l_\9J913  
package NetFox; <xUX&J=;  
import java.io.*; L[tq@[(IJ  
{_ {zs!r  
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public class FileAccessI implements Serializable{ BBa!le9P  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 KM/c^a4V  
RandomAccessFile oSavedFile; OlM3G^1e1  
long nPos; Bi7&yS5V  
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public FileAccessI() throws IOException ^e--4B9|  
{ iN
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this("",0);  8;O/x  
} "] ]aF1  
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public FileAccessI(String sName,long nPos) throws IOException a}[rk*QmZ  
{ ?~<NyJHN%  
oSavedFile = new RandomAccessFile(sName,"rw"); 6t3Zi:=I  
this.nPos = nPos; =m6<H  
oSavedFile.seek(nPos); \"b'Z2g  
} xn anca  
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public synchronized int write(byte[] b,int nStart,int nLen) V!QC.D<  
{ 8zQN[[#n  
int n = -1; )B"E+Q'h{7  
try{ mp8Zb&Ggb  
oSavedFile.write(b,nStart,nLen); ?;Z
nD(4?  
n = nLen; [= Xb*~  
} w!OYH1ds]_  
catch(IOException e) IEY\l{s  
{ S7b7zJ8A  
e.printStackTrace (); zZP&`#TAy  
} 7h`t-6<!q  
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return n; y 7z)lBy\  
} 2yVQqwQm  
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} U5[r&Y D  
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AJ z 1  
/* M,we,!B0  
**SiteInfoBean.java l=C|4@  
*/ j|@8Vx
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package NetFox;  p]jG ,S  
@{ L|&Mk!  
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public class SiteInfoBean { k0
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private String sSiteURL; //Site's URL seb/rxb  
private String sFilePath; //Saved File's Path Gn;^]8d  
private String sFileName; //Saved File's Name C|]Zpn#{K  
private int nSplitter; //Count of Splited Downloading File ^G "Qp8 "  
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public SiteInfoBean() :0p$r pJP  
{//nSplitter的缺省值为5 CHDt^(oa!B  
//default value of nSplitter is 5 4wx{i6  
this("","","",5); U-D00l7C  
} c/%GfB[w0  
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#-l+cu{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fn8|@)J  
{ 'fZ\uMdTx  
sSiteURL= sURL; ^~s!*T)\  
sFilePath = sPath; NleMZ  
sFileName = sName; ITD&wg  
this.nSplitter = nSpiltter; C%#u2C2  
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} bpa
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public String getSSiteURL() Kp19dp}'b  
{ FJFO0Hb6
  
return sSiteURL; E0.o/3Gw6  
} 9}+X#ma.Nc  
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public void setSSiteURL(String value) ^OK;swDW  
{ A.(e=;0bu  
sSiteURL = value; HE0m#  
} 83VFBY2q  
i/PL!'oq  
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public String getSFilePath() CtZOIx.;|  
{ a'O-0]g,  
return sFilePath; u1>WG?/`  
} h+Y>\Cxg  
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public void setSFilePath(String value) [kMWsiZ  
{ 1v*N]}`HU  
sFilePath = value; #k,.xMJ~  
} z'\BZ5riX<  
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public String getSFileName() =Z..&H5i  
{ "BIhd*K[~  
return sFileName; =&~ K;=:  
} @9l$jZ~x  
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w=^~M[%w  
public void setSFileName(String value) )k]{FM  
{ E:[!)UG|y  
sFileName = value; 5?|y%YH;R\  
} tH:?aP*2  
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public int getNSplitter() "V5_B^Gzb]  
{ Q |hBGH9:B  
return nSplitter; Q8_5g$X\  
} c?6(mU\x  
i_nUyH%b  
@6-3D/=  
public void setNSplitter(int nCount) &a6-+r  
{ G]dHYxG  
nSplitter = nCount; 0*j\i@  
} 5f75r  
} xXJzE|)1h!  
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/* )&-n-m@E  
**Utility.java c~d*SDca  
*/ ZIc-^&`r=  
package NetFox; ]SN5&S  
2\gbciJ[{(  
J3'0^JP*  
public class Utility { r^Soqom3  
@[1,i~H  
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public Utility() i,L"%q)C  
{ la
_  
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} V3axwg_  
S Z &[o&H  
//线程睡眠 ]agdVr^  
public static void sleep(int nSecond) MN>U jFA  
{ o Y<vKs^  
try{ YLV$#a3  
Thread.sleep(nSecond); ON"V`_dq+M  
} .o
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catch(Exception e) 5'xZ9K  
{ sZokiFJ  
e.printStackTrace (); U*T :p>&  
} {[+Q\<  
} ]O~/k~f  
?!bWUVC)_  
//日志 S7CD#Y[s  
public static void log(String sMsg) 1EHNg<J(  
{ _3gF~qr  
System.err.println(sMsg); a0 w  
} r\|"j8  
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VF9-&HuC  
public static void log(int sMsg) \0l"9 B.  
{ zrur-i$N+  
System.err.println(sMsg); JI92Dc*o  
} a#,lf9M  
} 6EG`0h6  
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/* 3a,7lTUuB  
**TestMethod.java )W![TIp  
*/ 8f#&CC!L  
package NetFox; s,GGO3^  
+'?axv6e  
]F,v#6qi  
public class TestMethod { O.P:~  
%:.00F([r  
$RV'DQO  
public TestMethod() D,'@b+B[  
{ ///xx/weblogic60b2_win.exe lD)QB!*v  
try{ ZD]5"oHY  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); E+E.z?>S  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); uY=}w"Db  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Nc:>]  
fileFetch.start(); dD"o~iEC  
} uEkUK|
 
catch(Exception e){e.printStackTrace ();} qnR
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tr\}lfK%  
} u-E*_%y  
g4*]R>f  
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public static void main(String[] args) hSDuByoi  
{ d.uJ}=|  
new TestMethod(); |^E#cI  
} gb_k^wg~1'  
} ryp@<}A]!d  
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