http断点续传简单实现（java)

/* kj6H+@ {  
**SiteFileFetch.java H%>^_:h  
*/ Lrmhr3 w5  
package NetFox; `"o{MaFA  
import java.io.*; virt[5w  
import java.net.*; (\'$$  
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public class SiteFileFetch extends Thread { 6AoKuT;
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean m>
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long[] nStartPos; //开始位置 `X)A$lLr  
long[] nEndPos; //结束位置 [b_qC'K[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 o+.ySSBl+  
long nFileLength; //文件长度
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boolean bFirst = true; //是否第一次取文件 0 vYG#S  
boolean bStop = false; //停止标志 \C
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File tmpFile; //文件下载的临时信息 Zl{9G?abCT  
DataOutputStream output; //输出到文件的输出流 =dsEt\ j  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） !K0 U..  
public SiteFileFetch(SiteInfoBean bean) throws IOException Lz!JLiMEET  
{ @|5B}%!  
siteInfoBean = bean; ioEjbqD<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); uEf=Vj}G  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &er,Wyc(  
if(tmpFile.exists ()) Y`(~eNX^%  
{ u:Ye`]~o  
bFirst = false; m'N8[ o|h  
read_nPos(); wa~zb!y<  
} (#Xs\IEVF  
else =
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{ &H P g>  
nStartPos = new long[bean.getNSplitter()]; t2YB(6w+xg  
nEndPos = new long[bean.getNSplitter()]; gVe]?Jva`  
} E-($Xc  
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} R7K`9 c1f6  
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public void run() #oR`_Dm)P  
{
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//获得文件长度 g"k4Z  
//分割文件 2r;h">  
//实例FileSplitterFetch a 9{:ot8,  
//启动FileSplitterFetch线程 _aBy>=2c$  
//等待子线程返回 u!&T}i:  
try{ RRpY%-8M  
if(bFirst) \yZVn6GVr  
{ hlZ{bO'f  
nFileLength = getFileSize(); IC(:RtJ  
if(nFileLength == -1) H XF
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{ jm@,Ihz=wI  
System.err.println("File Length is not known!"); ];"40/X  
} ecQ{ePoU  
else if(nFileLength == -2) r d-yqdJ  
{ g{i= $xc  
System.err.println("File is not access!"); 5IOGH*'U8  
} )<{u oH  
else .9WOTti  
{ Bs`{qmbC  
for(int i=0;i<nStartPos.length;i++) =mF"D:s*  
{ /qMnIo  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} /]_|uN)Q  
for(int i=0;i<nEndPos.length-1;i++) #"lb9._M  
{ /!^,+  
nEndPos = nStartPos[i+1]; *^Ges;5$"  
} 9bM kP2w>  
nEndPos[nEndPos.length-1] = nFileLength; c9o]w8p/  
} \uZ|2WG`  
} ^,mN-.W  
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MnZljB  
//启动子线程 /H"fycZ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )Tp"l"(G  
for(int i=0;i<nStartPos.length;i++) F'sX ^/;  
{ 7(uz*~Z?`0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dP+wcl4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), U#]J5'i  
nStartPos,nEndPos,i); ,|3_
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?o$t{AQ  
fileSplitterFetch.start(); OzD\*,{7  
} Wh)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7}y@VO6]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6wj o:I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u$C\#y7  
nEndPos = " + nFileLength); ]1XtV<  
// fileSplitterFetch[nPos.length-1].start(); B@NBN&Fr  
}( CYok  
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//等待子线程结束 1#%H!GKvTU  
//int count = 0; ot[ZFF\  
//是否结束while循环 AIY 1sSK  
boolean breakWhile = false; |JF,n~n  
*4NY"EwjN  
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while(!bStop) :r ~iFP*  
{ J(@" 7RX  
write_nPos(); jf`w8*R  
Utility.sleep(500); =}kISh  
breakWhile = true; FU/:'/ L  
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for(int i=0;i<nStartPos.length;i++) ?jUgDwc(w  
{ 4H%#Sn#L^!  
if(!fileSplitterFetch.bDownOver) f<iK%  
{ <5}I6R;  
breakWhile = false; 3<"j/9;K'  
break; @&`^#pok  
} Xwdcy J!  
} i&^JG/a  
if(breakWhile) {Ji&rk}NP  
break; )B"{B1
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//count++; x{
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//if(count>4) nOd;Zw  
// siteStop(); XHj%U  
} JbL3/h]  
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System.err.println("文件下载结束！");  YTZ :D/  
} Zi+FIQ(  
catch(Exception e){e.printStackTrace ();} Gf3-%s xA  
} 1fMV$T==K  
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//获得文件长度 fs;\_E
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public long getFileSize() V^R,j1*  
{ " "m-5PGYo  
int nFileLength = -1; )Z1&`rv  
try{ 9aLd!PuTN  
URL url = new URL(siteInfoBean.getSSiteURL()); gC(S(osF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4'dN7E1*f  
httpConnection.setRequestProperty("User-Agent","NetFox"); _s#]WyU1g  
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int responseCode=httpConnection.getResponseCode(); &g&,~Y/z;  
if(responseCode>=400) JygJ4RI%j  
{ {l!{b1KJ  
processErrorCode(responseCode); 
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return -2; //-2 represent access is error jT$J~MpHh  
} 6xtgnl#T  
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String sHeader; ^.iRU'{  
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for(int i=1;;i++) _b&26!gl  
{ 8..|-<w  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J^yqu{
  
//Utility.log(in.readLine()); X,aRL6>r  
sHeader=httpConnection.getHeaderFieldKey(i); 6`Y:f[VB  
if(sHeader!=null) }Vob)r{R@  
{ HVoPJ!K3  
if(sHeader.equals("Content-Length")) 4)D~S4{E5  
{ "5<!   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ><D2of|  
break; &8l?$7S"_/  
} keRLai7h  
} Y)F(-H)  
else \ui'~n_t]  
break; ,'HjL:r  
} RHn3\N  
} M0xhcU_  
catch(IOException e){e.printStackTrace ();} G.<0^q,  
catch(Exception e){e.printStackTrace ();} ,
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Utility.log(nFileLength); %m f)BC  
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return nFileLength; /"st sF  
} !ITM:%  
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//保存下载信息（文件指针位置） K/Yeh<_&  
private void write_nPos() f!yl&ulKU  
{ -ak.wwx\  
try{ s<#BxN  
output = new DataOutputStream(new FileOutputStream(tmpFile)); O&aD]~|
  
output.writeInt(nStartPos.length); !Whx^B:  
for(int i=0;i<nStartPos.length;i++) zn^7#$fC  
{
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// output.writeLong(nPos); ?+7~E8  
output.writeLong(fileSplitterFetch.nStartPos); T^#d;A  
output.writeLong(fileSplitterFetch.nEndPos); ibZ[U p?  
} 1)h<
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output.close(); eq%cRd]u  
} /cx'(AT  
catch(IOException e){e.printStackTrace ();} .wq j
 
catch(Exception e){e.printStackTrace ();} `3ha~+Goo!  
} AEnkx!o  
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//读取保存的下载信息（文件指针位置） oqh@(<%  
private void read_nPos() -f ~1Id  
{ eDP&W$s#  
try{ G)[gLD{g?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); mD% qDKI  
int nCount = input.readInt(); c-&Q_lB  
nStartPos = new long[nCount]; >gL&a#<S  
nEndPos = new long[nCount]; .!L{yU,  
for(int i=0;i<nStartPos.length;i++)  "O9n|B  
{ r
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nStartPos = input.readLong(); PR!0=E*}  
nEndPos = input.readLong(); +ug2p;<B  
} k=kkF"  
input.close(); =s*c(>  
} )K]p^lO  
catch(IOException e){e.printStackTrace ();} wAW{{ p  
catch(Exception e){e.printStackTrace ();} 8r"-3<*  
} w/ZP.B  
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private void processErrorCode(int nErrorCode) ;:oJFI#;  
{ {`*Fu/Upb  
System.err.println("Error Code : " + nErrorCode); +924_,zF  
} "2-D[rYZ  
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//停止文件下载 7_Te-i  
public void siteStop() Z?qLn6y1W  
{ 1>\V>g
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bStop = true; |ITCw$T  
for(int i=0;i<nStartPos.length;i++) ^Tj{}<yT  
fileSplitterFetch.splitterStop(); 4zhh**]B  
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} %wru)  
} G?LC!9MB  
//负责部分文件的抓取 'lpCwH  
**FileSplitterFetch.java WQN`y>1#@_  
*/ ?8s$RYp14  
package NetFox; 5`e;l$ M`  
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import java.io.*; YW~ 9N  
import java.net.*; N<4 nb  
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public class FileSplitterFetch extends Thread { *'H\`@L  
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String sURL; //File URL M~
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long nStartPos; //File Snippet Start Position IIGx+>  
long nEndPos; //File Snippet End Position `S4*~Xx  
int nThreadID; //Thread's ID 3:#6/@wQ  
boolean bDownOver = false; //Downing is over }.8yKj^p  
boolean bStop = false; //Stop identical \i-CTv6f  
FileAccessI fileAccessI = null; //File Access interface `ItoL7bi  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException KrG,T5  
{ NhTJB7  
this.sURL = sURL; cVMRS
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this.nStartPos = nStart; HrZX~JnTmf  
this.nEndPos = nEnd; SvkCx>6/G  
nThreadID = id; nIL67&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3Ur_?PM+C  
} j@+$lU*r  
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public void run() IaOR%Bg  
{ .w{Y3,dd>  
while(nStartPos < nEndPos && !bStop) s3@mk\?qMe  
{ P4{~fh(  
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try{ .I#_~
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URL url = new URL(sURL); A1Uy|Dl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B1U!*yzG6  
httpConnection.setRequestProperty("User-Agent","NetFox"); GNrRc3dr$  
String sProperty = "bytes="+nStartPos+"-"; tEo-Mj5:  
httpConnection.setRequestProperty("RANGE",sProperty); NMhpKno  
Utility.log(sProperty); Pe\Obd8d  
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InputStream input = httpConnection.getInputStream(); LxWd_B  
//logResponseHead(httpConnection); c1a

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byte[] b = new byte[1024]; [YODyf}M>\  
int nRead; :O&jm.2m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) T2rBH]5  
{ iV#A-9  
nStartPos += fileAccessI.write(b,0,nRead); kQd|qZ=:w  
//if(nThreadID == 1) i0+e3!QU  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /|H9Gm  
} 7mXXMm  
^
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Utility.log("Thread " + nThreadID + " is over!"); %*Mr ^=  
bDownOver = true; S|@/"?DC  
//nPos = fileAccessI.write (b,0,nRead); N`?/kubD  
} 0T(+
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catch(Exception e){e.printStackTrace ();} id8QagJ  
} =)g}$r &<  
} @b.,pwZF  
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,:'JJZg@  
//打印回应的头信息 $-t@=N@vO?  
public void logResponseHead(HttpURLConnection con) /hVwrt(  
{ jC}HNiM78  
for(int i=1;;i++) E11C@%  
{ +Q);t,  
String header=con.getHeaderFieldKey(i); ns\I Y<Yo  
if(header!=null) M?}:N_9<J  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Hsv
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Utility.log(header+" : "+con.getHeaderField(header));  qbS6#7D  
else  |xg#Q`O  
break; {5c?_U  
} oq$#wiV"Q  
} 2.MUQ;OX  
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public void splitterStop() _&s pMf  
{ 9c,/490Q  
bStop = true; =23@"ji@D  
} olxxs(  
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} 5=#d#dDc  
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/* VMJaL}J]  
**FileAccess.java k%O3\q  
*//文件访问(定位，写) -oUNK}>  
package NetFox; OUGkam0UK  
import java.io.*; ;]>)6  
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public class FileAccessI implements Serializable{ Tl[*(|/C  
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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 hjFht+j
1  
RandomAccessFile oSavedFile; @>~\So|  
long nPos; HB}rpiB  
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public FileAccessI() throws IOException 7_)38  
{ _TsN%)m  
this("",0); 1t?OD_d!8  
} A9K$:mL<2  
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public FileAccessI(String sName,long nPos) throws IOException zG9D Ph  
{ =VZ_';b h  
oSavedFile = new RandomAccessFile(sName,"rw"); :@-yK8q's  
this.nPos = nPos; !P^Mo> "  
oSavedFile.seek(nPos); @sg.0GR  
} yOKzw~;0%  
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public synchronized int write(byte[] b,int nStart,int nLen) o'(BL:8s  
{ 6g"h}p\{S  
int n = -1; ['pO=ho  
try{ 0hGmOUO  
oSavedFile.write(b,nStart,nLen); UXpp1/d|e  
n = nLen; vF'>?O?  
} ;sAGTq  
catch(IOException e) oxL<\4)WJ  
{ dc1Zh W4  
e.printStackTrace (); g<0K i^#  
} J!5b~8`v  
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return n; 9609  
} D
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} /Qr`au  
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/* y1PyH  
**SiteInfoBean.java .o/uA  
*/ HZWt>f  
package NetFox; D^.  c:  
a*.#Zgy:lK  
7[qL~BT+  
public class SiteInfoBean { qA`@~\qh"  
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private String sSiteURL; //Site's URL L2EQ 9i'[  
private String sFilePath; //Saved File's Path C5TV}Bq\  
private String sFileName; //Saved File's Name @d 7V@F0d  
private int nSplitter; //Count of Splited Downloading File c$&({Z{1  
YOGj__:  
0\ (:y^X  
public SiteInfoBean() E JuTv%Y8  
{//nSplitter的缺省值为5 <y^_&9  
//default value of nSplitter is 5 @/^mFqr2  
this("","","",5); zN]%p>,)HB  
} _[Imwu}  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) QOg >|"KL  
{ `m<O!I"A  
sSiteURL= sURL; >|kD(}Axf  
sFilePath = sPath; `kQosQV  
sFileName = sName; 457{9k  
this.nSplitter = nSpiltter; 81s }4  
g([:"y?  
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} A7+Z
Y,  
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public String getSSiteURL() ?-mOAHW0q  
{ \DZ.#=d  
return sSiteURL; MSvZ3[5Io  
}
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public void setSSiteURL(String value) QNU~G3  
{ fpo{`;&F  
sSiteURL = value; ]gcOMC  
} \2a;z<(  
8/dMvAB1So  
s[0`  
public String getSFilePath() o&%v"#H2  
{ 4^2>KC_  
return sFilePath; Q9O_>mZy  
} lm;hW&O9  
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k
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public void setSFilePath(String value) TK\3mrEI  
{ ' :B;!3a0d  
sFilePath = value; -~~h1  
} Zc1x"j  
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public String getSFileName() Z)E)-2U$@  
{ ,jis@]:  
return sFileName; =cjO]  
} ]Rxo}A  
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~r8<|$;  
public void setSFileName(String value) 0@cIj ]  
{ pIcg+~  
sFileName = value; ySO\9#Ho  
} 1a{3k#}  
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public int getNSplitter() pz['o  
{ /C
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return nSplitter; 1;=L] L?  
} %mT/y%&:  
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public void setNSplitter(int nCount) Dbn344s  
{ ye$_=KARP  
nSplitter = nCount; kpn|C 9r  
} 9Tt%~m^  
} pK3A/ry<  
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.@OQ$D<  
/* Pa3-0dUr  
**Utility.java !9/`PcNIpy  
*/ QNMZR  
package NetFox; <>\|hno}  
%`5(
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public class Utility { a&8K5Z%0  
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public Utility() iXnXZ|M  
{ ftPps-  
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} G:$
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15j5F5P   
//线程睡眠 VR>!Ch  
public static void sleep(int nSecond) t(*n[7e  
{ 6Oy:5Ps8a  
try{ 6;'[v}O^^  
Thread.sleep(nSecond); IVSC7SBiT  
} X|hYZR  
catch(Exception e) LQPQ !):;  
{ R'c dEo
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e.printStackTrace (); M+ %O-B  
} (rBsh6@)  
} Zio!j%G  
cl^UFlf[  
//日志 V[/9?5pM  
public static void log(String sMsg) 06.%9R{  
{ N+c|0  
System.err.println(sMsg); q%;cu1^"M  
} X.4WVI  
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; D
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public static void log(int sMsg) [#gm[@d,  
{ PDD2ouv4  
System.err.println(sMsg); `S|F\mI~  
} $GRw
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} 9abUh
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a[~[lk=7  
GCN-T1HvA2  
/* Vp]7n!g4l  
**TestMethod.java |9S8sfw  
*/ <h/q^|tZ{  
package NetFox; M{24MF   
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_$>);qIP4  
public class TestMethod { aF?_V!#cT  
vf3)T;X>  
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public TestMethod() Lbz/M_G  
{ ///xx/weblogic60b2_win.exe @QmN= X5  
try{ G
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Sn
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ck]I?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); aYa`ex  
fileFetch.start(); -nNKUt.I  
} @3c'4O   
catch(Exception e){e.printStackTrace ();} im&N&A  
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} /W,hO
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public static void main(String[] args) 3:jxr  
{ jnp~ACN,  
new TestMethod(); W've
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} $||WI}k3V  
} p4z4[=-:  
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