http断点续传简单实现（java)

/* JX\T {\m#  
**SiteFileFetch.java il>x!)?o  
*/ nzE,F\k  
package NetFox; v1
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import java.io.*; ej"o?
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import java.net.*; 8F`BJ6='  
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public class SiteFileFetch extends Thread { rz[uuY7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ]2xx+P#Y  
long[] nStartPos; //开始位置 5;K-,"UQ  
long[] nEndPos; //结束位置 74}eF)(me  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 sx-Hw4.a"  
long nFileLength; //文件长度 I"F .%re  
boolean bFirst = true; //是否第一次取文件 ><#2O  
boolean bStop = false; //停止标志 mS)|6=Y  
File tmpFile; //文件下载的临时信息 vzohq1r5  
DataOutputStream output; //输出到文件的输出流 &` 00/p  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） n$OE~YwP{  
public SiteFileFetch(SiteInfoBean bean) throws IOException hk5E=t~&  
{ O
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siteInfoBean = bean; _r<zSH%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _,Rsl$Tk'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -e`oW.+  
if(tmpFile.exists ()) V$-~%7@>;9  
{ 1|l)gfc
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bFirst = false; VT5cxB<  
read_nPos(); ,>QMyI hv  
} *b6I%MZn  
else }o!#_N0T  
{ Xew1LPI  
nStartPos = new long[bean.getNSplitter()]; StdS$XW  
nEndPos = new long[bean.getNSplitter()]; XYK1-m}2  
} A'~%
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{ /F rs*AF  
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} _Ra<|NVQh  
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public void run() ]e@0T{!  
{ !e:iB7<  
//获得文件长度 {;Y 89&*R  
//分割文件 k"q!|+&Fs  
//实例FileSplitterFetch E
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//启动FileSplitterFetch线程
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//等待子线程返回 L= :d!UF  
try{ S/nj5Lh  
if(bFirst) +&7[lsD*  
{ RVgPH<1X@e  
nFileLength = getFileSize(); PkPDVv  
if(nFileLength == -1) (<bm4MPf  
{ d%#!nq{vd  
System.err.println("File Length is not known!"); m?D <{BQ;  
} \uU=O )  
else if(nFileLength == -2) (b/A|hl  
{ LC,*H0  
System.err.println("File is not access!");
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} <fC@KY>#  
else 2qs>Bshf  
{ @)W(q5)}9"  
for(int i=0;i<nStartPos.length;i++) .pS&0gBo\  
{ PcHSm/d0e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jb|mip@` <  
} %1-K);SJ  
for(int i=0;i<nEndPos.length-1;i++) e-CNQnO~  
{ kCaO\#ta  
nEndPos = nStartPos[i+1]; ,67"C2Y  
} "*++55  
nEndPos[nEndPos.length-1] = nFileLength; T3USNc51  
} W_[|X}lWP  
} AW,v  
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//启动子线程 X q}Ucpj  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; HE#,(;1i  
for(int i=0;i<nStartPos.length;i++) 7BL|x  
{ ||-nmOy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q^
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IVI~1~  
nStartPos,nEndPos,i); eu#,WwlG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Zg -]sp]  
fileSplitterFetch.start(); &8[ZN$Xe"  
} CS/Mpmsp  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !c3```*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :a_BD  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?z2jk  
nEndPos = " + nFileLength); ?QCmSK=
L  
// fileSplitterFetch[nPos.length-1].start(); w)+wj[6 E  
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//等待子线程结束 ,HFs.9#&B  
//int count = 0; uh]"(h(>  
//是否结束while循环 z$JX'(<Z7  
boolean breakWhile = false; S~KS9E~\  
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while(!bStop) J|VK P7  
{ 9T(L"9r-e  
write_nPos(); ;B&^yj&;  
Utility.sleep(500); BjJ,"sT  
breakWhile = true; c_ La^HS  
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for(int i=0;i<nStartPos.length;i++) Fi mN?s  
{ >_XOc  
if(!fileSplitterFetch.bDownOver) *IC^IC:  
{ A
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breakWhile = false; O0^?f/&k  
break; >T<6fpXuk2  
} \|CPR6I  
} 10p8|9rE}B  
if(breakWhile) yn SBVb!)  
break; ` ^DjEdUN  
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 %BUEX  
//count++; _ Yfmxn8V  
//if(count>4) 3Jk[/.h  
// siteStop(); H&M1>JtE  
} |xn#\epy@  
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System.err.println("文件下载结束！"); U^MuZ  
} .%q$d d>>  
catch(Exception e){e.printStackTrace ();}
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} 93j{.0]X  
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//获得文件长度 eP"`,<  
public long getFileSize() zj<ahg%z  
{ \V,c]I   
int nFileLength = -1; l^\(ss0~  
try{ U4BqO :sd  
URL url = new URL(siteInfoBean.getSSiteURL()); bmu6@jT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [F+(^- (  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y9
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int responseCode=httpConnection.getResponseCode(); _a](V6  
if(responseCode>=400) @Mm/C?#*O  
{ jpRBER_X  
processErrorCode(responseCode); %SAw;ZtQ:  
return -2; //-2 represent access is error `OqM8U @  
} ;j{7!GeKa  
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MaO"#{i  
String sHeader; .20V 3  
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for(int i=1;;i++) Y;Ap9i*  
{ 8nCp\0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); OOnX`  
//Utility.log(in.readLine()); g+xw$A ou  
sHeader=httpConnection.getHeaderFieldKey(i); 3X;{vO\a1  
if(sHeader!=null) 8'A72*dhX  
{ >H>gH2qp  
if(sHeader.equals("Content-Length")) [$pmPr2  
{ j(iuz^I  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~:4~2d|  
break; >{C\H.N  
} t6+YXjXK  
} `0{ S3v  
else 5,1{Tv`  
break; WK0C  
} t V03+&jF  
} q
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catch(IOException e){e.printStackTrace ();} Tk*w3c"$  
catch(Exception e){e.printStackTrace ();} WF2NG;f=  
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Utility.log(nFileLength); oKA&An  
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return nFileLength; \ECu5L4  
} {hQ6K)s  
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//保存下载信息（文件指针位置） ecj7BT[mLI  
private void write_nPos() TW7:q83{l  
{ Z o=]dBp.  
try{ 1D F/6y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >xqM5#m`E$  
output.writeInt(nStartPos.length); (gwj)?:  
for(int i=0;i<nStartPos.length;i++) c0_E_~  
{ V5mlJml2(  
// output.writeLong(nPos); `]=oo%(h  
output.writeLong(fileSplitterFetch.nStartPos); vi!YN|}\  
output.writeLong(fileSplitterFetch.nEndPos); ['q&@_d7  
} t{dSX?<nt  
output.close(); AQss4[\Dx  
} }fZ`IOf  
catch(IOException e){e.printStackTrace ();} u,1}h L  
catch(Exception e){e.printStackTrace ();} +/rH(Ni  
} !2tW$
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//读取保存的下载信息（文件指针位置） LOvHkk@+  
private void read_nPos() + H_WlYg-  
{ +*}{`L- :  
try{ +oc >S  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jjzA .8?(7  
int nCount = input.readInt(); 2;$k(x]  
nStartPos = new long[nCount]; )JD(`  
nEndPos = new long[nCount]; ;`dh fcU  
for(int i=0;i<nStartPos.length;i++) 4/e60jA  
{ egk7O4zwP  
nStartPos = input.readLong(); P[ r];e  
nEndPos = input.readLong(); 47r&8C+&\  
} X^@I].  
input.close(); 17|np2~  
} pI.+"Hz  
catch(IOException e){e.printStackTrace ();} Sv'y e  
catch(Exception e){e.printStackTrace ();} l"(6]Z 4  
} W_`A"WdT.  
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private void processErrorCode(int nErrorCode) p|+B3  
{ \4d.sy0&>-  
System.err.println("Error Code : " + nErrorCode); 0d^Z uTN  
} ({^9<Us  
e>}}:Ud  
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//停止文件下载 Q`%R
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public void siteStop() lrWQOYf2  
{ g(C|!}ex/  
bStop = true; |X19fgk  
for(int i=0;i<nStartPos.length;i++) crcA\lJf  
fileSplitterFetch.splitterStop(); (u3s"I d  
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} j;1-p>z  
} ccFn.($p?,  
//负责部分文件的抓取 .w?(NZ2~  
**FileSplitterFetch.java @}-r&/#  
*/ ->^~KVh&  
package NetFox; h#r^teui)  
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import java.io.*; a
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import java.net.*; b5G}3)'w  
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public class FileSplitterFetch extends Thread { JAjmrX  
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String sURL; //File URL 4mjgt<`  
long nStartPos; //File Snippet Start Position Y-mK+12  
long nEndPos; //File Snippet End Position {c?JuV4q?  
int nThreadID; //Thread's ID lbdTQ6R  
boolean bDownOver = false; //Downing is over I` K$E/ns  
boolean bStop = false; //Stop identical O,2~"~kF  
FileAccessI fileAccessI = null; //File Access interface i':i_kU  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {66sB{P  
{ a]Eg!Q  
this.sURL = sURL; TjMe?p  
this.nStartPos = nStart; h%; e0Xz|  
this.nEndPos = nEnd; X?:o;wB  
nThreadID = id; rl#vE's6.e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 / $  :j  
} 57a2^  
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public void run() >T2LEW  
{ VV4Gjc  
while(nStartPos < nEndPos && !bStop) 9Jf)!o8  
{ i,A#&YDl  
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try{ u]NZ`t%AP  
URL url = new URL(sURL); =*
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &6 s) X  
httpConnection.setRequestProperty("User-Agent","NetFox"); DS-0gVYeDW  
String sProperty = "bytes="+nStartPos+"-"; ?[<Tx-L  
httpConnection.setRequestProperty("RANGE",sProperty); j"^+oxH  
Utility.log(sProperty); }8|[;Qa`y  
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InputStream input = httpConnection.getInputStream(); -9
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//logResponseHead(httpConnection); T9)nQ[  
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byte[] b = new byte[1024];
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int nRead; <!-sZ_qq  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) C51bc6V  
{ CQ`=V2:"ON  
nStartPos += fileAccessI.write(b,0,nRead); LE5.b]tv2  
//if(nThreadID == 1) ^;,M}|<h  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a?|vQ*W  
} *<N3_tx"  
[ EFMu;q  
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Utility.log("Thread " + nThreadID + " is over!"); 09A X-JP  
bDownOver = true; 2%*MW"Q  
//nPos = fileAccessI.write (b,0,nRead); ] Z8Vj7~  
} b2 _Yu^  
catch(Exception e){e.printStackTrace ();} t?o,RN:  
} b|Q)[y]  
} QB.J,o*XD4  
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//打印回应的头信息 W$U0[^1  
public void logResponseHead(HttpURLConnection con) O#wpbrJ  
{ ,B4VT 96*  
for(int i=1;;i++) 6sIL.S~c)  
{ PB%-9C0  
String header=con.getHeaderFieldKey(i); L %ip>  
if(header!=null) M8H5K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +^*iZ6{+7  
Utility.log(header+" : "+con.getHeaderField(header)); PJxH7|GSi  
else '(? uPr  
break; }:0uo5B7  
} (feTk72XX  
} ?USQlnr:R/  
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public void splitterStop() 0 a]/%y3V  
{ ~~/xRs  
bStop = true; ^c~)/F/cF  
} LjL[V'JL  
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} E?(xb B  
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/* #%J5\+ua  
**FileAccess.java $+.l*]  
*//文件访问(定位，写) l3N I$Zu  
package NetFox; 7t,t`  
import java.io.*; 2[0JO.K 4  
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public class FileAccessI implements Serializable{ VMoSLFp^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 v]__%_  
RandomAccessFile oSavedFile; ?+T^O?r|O  
long nPos; >]o}}KF?  
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public FileAccessI() throws IOException {3N'D2N  
{  L4uFNM]  
this("",0); OL_{_K(w  
} 8M@
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/  
public FileAccessI(String sName,long nPos) throws IOException Y>jiXl?&  
{ AeAp0cbet  
oSavedFile = new RandomAccessFile(sName,"rw"); }|%eCVB  
this.nPos = nPos; Xf)|Pu  
oSavedFile.seek(nPos); 099sN"kf  
} ~=R SKyzt  
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public synchronized int write(byte[] b,int nStart,int nLen) EUsI%p  
{ oK{ V7  
int n = -1; UT}i0I9  
try{ oD}uOC}FS{  
oSavedFile.write(b,nStart,nLen); Kscd}f)yx?  
n = nLen; EGl^!.'  
} "UwH\T4I  
catch(IOException e) czlFr|O;  
{ ,lCgQ0}<  
e.printStackTrace (); xkOpa,=FI  
} y4+;z2'>  
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return n; e.c3nKXZ q  
} KR7@[
  
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} =IAsH85Q  
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/* [pVamE  
**SiteInfoBean.java /c):}PJ^#7  
*/ `K,1K  
package NetFox; G\NPV
'  

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public class SiteInfoBean { wcDRH)AW.  
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private String sSiteURL; //Site's URL ] }f9JNf$  
private String sFilePath; //Saved File's Path Pz$R(TV  
private String sFileName; //Saved File's Name q\\gpCgp  
private int nSplitter; //Count of Splited Downloading File v
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public SiteInfoBean() A<;SnXm  
{//nSplitter的缺省值为5 %kgkXc~6|x  
//default value of nSplitter is 5 +**!@uY  
this("","","",5); .5  
} h<~7"ONhV  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "kZ[N'z(  
{ q\H[am  
sSiteURL= sURL; iX3HtIBj'  
sFilePath = sPath; N>>uCkC  
sFileName = sName; tDAhyy73  
this.nSplitter = nSpiltter; "fq{Y~F%`  
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} B7]MGXC  
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public String getSSiteURL() XV^1tX>f{  
{ Hty0qr3  
return sSiteURL; A/`%/0e  
} KF4PJi;*  
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public void setSSiteURL(String value) qTQBt}  
{ z3uW)GQ.  
sSiteURL = value; yv)ux:P&+  
} sN5B7)Vc  
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public String getSFilePath() W0}B'VS.I  
{ qoAj] ")  
return sFilePath; c_elShK8#  
} MTUn3;c/  
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public void setSFilePath(String value) B-l'
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{ Uk\Id~xLV  
sFilePath = value; [k-+AA>:  
} B2ec@]uD`  
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public String getSFileName() @}kv-*  
{ xCtmXo  
return sFileName; E}ZJ)V7  
} A2|Ud_  
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public void setSFileName(String value) Ge<nxl<Bd  
{ @]ao"ui@/  
sFileName = value; 5ms""LD/  
} ]Zmj4vK J  
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public int getNSplitter() B,{K*-7)MX  
{ MR}Agu#LG  
return nSplitter; ciMzf$+G$  
} K#"O a h  
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public void setNSplitter(int nCount) 2,*M|+W~  
{ ."FuwKSJCo  
nSplitter = nCount; `hb%+-lj+  
} D::rGB?.b  
} G\(|N9^:  
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/* 50={%R  
**Utility.java |DsnNk0c
 
*/
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package NetFox; 5L!y-3  
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public class Utility { `]W|8M  
|6<p(i7  
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public Utility() Z4\=*ic@  
{ w4gg@aO  
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} #_u~/jhX  
V5rST +  
//线程睡眠 KY~-;0x  
public static void sleep(int nSecond) BT(CM,bp  
{ rOVVL%@QqJ  
try{ w`5xrqt@  
Thread.sleep(nSecond); Ih"XV  
} cCxBzkH6  
catch(Exception e) p3^m9J  
{ ,S!azN=  
e.printStackTrace (); }+sT4'Ah>  
} Er{>p|n=  
} yNTK
.  
<%"b9T`'  
//日志 hq #?kN  
public static void log(String sMsg) \o^2y.q:>  
{ j*vYBGD  
System.err.println(sMsg); #Q /Arq  
} =
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$b mLu=9  
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public static void log(int sMsg) (I./ Uu%  
{ }1upi=+aE  
System.err.println(sMsg); 1aTB%F  
} :*KHx|Q  
} L'kmNVvYN  
P ! _rEV  
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/* q?8| [.  
**TestMethod.java BSVx
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*/ 9_5ow  
package NetFox; |/)${*a4n
 
:n-]>Q>5=k  
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public class TestMethod { q0zr E5  
sjV!5Z  
\vO,Ee~#W  
public TestMethod() 5yz(>EVH  
{ ///xx/weblogic60b2_win.exe @8I4[TE  
try{ AQwdw>I-FX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &*aIEa^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6g)GY"49  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,JQp'e  
fileFetch.start(); ]'=)2 .}  
} VB*oGG  
catch(Exception e){e.printStackTrace ();} 2V#>)R#k  
6l
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_  
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} +O?KNZ  
7](
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public static void main(String[] args) pWJFz-  
{ V: TM]  
new TestMethod(); L bmawi^  
} JVSA&c%3  
} ybKWOp:O  
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