http断点续传简单实现（java)

/* fB|rW~!v  
**SiteFileFetch.java ZGf R:a)wc  
*/ v1<3y~'f  
package NetFox; M%5qx,JQY  
import java.io.*; nAG2!2_8  
import java.net.*; R2yiExw<  
(e6JI]tz{  
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public class SiteFileFetch extends Thread { i[sHPEml(5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ='a[(C&Y  
long[] nStartPos; //开始位置 e<6fe-g9;  
long[] nEndPos; //结束位置 <
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 x hBlv  
long nFileLength; //文件长度 ,<0R'R  
boolean bFirst = true; //是否第一次取文件 XT> u/Z)  
boolean bStop = false; //停止标志 _so\h.lt  
File tmpFile; //文件下载的临时信息 v8W.84e-  
DataOutputStream output; //输出到文件的输出流 ~cQ./G4  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） x;dyF_*;  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?8X;F"Ba  
{ .;)7)%  
siteInfoBean = bean; W0J d2*]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); XdjM/hB{fD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0sM{yGu=,  
if(tmpFile.exists ()) ER<LP@3k  
{ G?)NDRM  
bFirst = false; l8 k@.<nCO  
read_nPos(); tSran  
} 9`]Gosz  
else 0+%{1JkJq  
{ q">lP(t  
nStartPos = new long[bean.getNSplitter()]; *UhYX)J  
nEndPos = new long[bean.getNSplitter()]; uOUgU$%zqH  
} s9+Rq*Qd  
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} 8Y?zxmwn]  
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public void run() o|O730"2F  
{ _b|mSo,{Y  
//获得文件长度 j>Wb$p6S  
//分割文件 cu*8,*FU  
//实例FileSplitterFetch 2%P{fJbwd  
//启动FileSplitterFetch线程 A?V}$PTlx  
//等待子线程返回 6U~AKq"+f  
try{ E7X6Shng  
if(bFirst) 9"hH2jc  
{ 
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nFileLength = getFileSize(); >>/|Q:  
if(nFileLength == -1) Yci>'$tQ  
{ 'Dw+k;RH  
System.err.println("File Length is not known!"); F3+ ;2GG2  
} 2*;qr|h,  
else if(nFileLength == -2) $2uk;&"?A=  
{ qg1s]c~0u  
System.err.println("File is not access!"); Y1fcp_]m  
} "g27|e?y  
else zGgPW  
{ z,dh?%H>X  
for(int i=0;i<nStartPos.length;i++) hS&3D6Gt  
{ @
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); #$W02L8  
} 0T,uH  
for(int i=0;i<nEndPos.length-1;i++) ZD!?mR+-  
{ q_iPWmf p*  
nEndPos = nStartPos[i+1]; X)7_@,7  
} kq|(t{@Rp  
nEndPos[nEndPos.length-1] = nFileLength; :Ywb  
} 8LuM eGs  
} >}<1  
Xb#!1hA  
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//启动子线程 R 6JHR
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; iB4`w\-o  
for(int i=0;i<nStartPos.length;i++) x6yYx_  
{ NzS(,F  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pGZiADT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ZtHTl\z  
nStartPos,nEndPos,i); ? nx3#<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u7||
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fileSplitterFetch.start(); PY81MTv0;  
} 9u[^9tL+D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k-it#'ll{x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \jA#RF.W  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", RW"QUT  
nEndPos = " + nFileLength); 7s
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// fileSplitterFetch[nPos.length-1].start(); Cp"a,%b6u  
P=3mLz-  
 T.d1?  
//等待子线程结束 ,f*Q3 S/I  
//int count = 0; ZZ'5BfI"I%  
//是否结束while循环 lo!^h]iE!  
boolean breakWhile = false; +G:CR,Z>+  
>lPWji'4;  
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while(!bStop) s#Ayl]8r  
{ p"@[2hK  
write_nPos(); f4'WT
  
Utility.sleep(500); &|9K~#LVS  
breakWhile = true; e|-&h `[  
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for(int i=0;i<nStartPos.length;i++) h~EGRg  
{ '[WVP=M<XV  
if(!fileSplitterFetch.bDownOver) J2ZV\8t  
{ ohU}ST:9  
breakWhile = false; '`s+e#rs4{  
break; r>ziQq8C&  
} X!x
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} XoNBq9Iu  
if(breakWhile) 216=7O2F  
break; L;GkG! g  
<
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//count++; %T6 sm  
//if(count>4) gpw,bV  
// siteStop(); OLS/3c z  
} X aE;i57$l  
Z".Xroq~  
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System.err.println("文件下载结束！"); C'7DG\pr  
} r'(*#  
catch(Exception e){e.printStackTrace ();} kqkTz_r|H  
} Gf=3h4  
xlcL;
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//获得文件长度 gNHS:k\"  
public long getFileSize() @}\i`H1s  
{ W1Vy5V|M  
int nFileLength = -1; ;Zm-B]\  
try{ h6b(FTC^  
URL url = new URL(siteInfoBean.getSSiteURL()); G^|!'V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vf5q8/a  
httpConnection.setRequestProperty("User-Agent","NetFox"); baoyU
#X9  
9-+N;g!q  
+OI<0  
int responseCode=httpConnection.getResponseCode(); xp?YM35  
if(responseCode>=400) ^c<8|lK L@  
{ {E[t(Ig  
processErrorCode(responseCode); j7BLMTF3v  
return -2; //-2 represent access is error VUi> ]v/e  
} \,xa_zeO
 
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String sHeader; t6uYFxE  
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for(int i=1;;i++) A.vf)hO  
{
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z;<:=#  
//Utility.log(in.readLine()); KKq%'y)u^  
sHeader=httpConnection.getHeaderFieldKey(i); $cWt^B'  
if(sHeader!=null) %*NED zy  
{ -7KoR}Ck!  
if(sHeader.equals("Content-Length")) .?vHoNvo  
{ jF-:e;-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9}wI@  
break; a&2UDl%K  
} [vY#9W"!  
} 5Gs>rq" #  
else [D+,I1u2h  
break; fGd1  
} 8@[S,[
  
} RFLfvD<  
catch(IOException e){e.printStackTrace ();} R< L =&I  
catch(Exception e){e.printStackTrace ();} <+-=j  
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q  
Utility.log(nFileLength); mlxtey6H3  
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return nFileLength; +_L]d6  
} iZLy#5(St  
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Y7zs)W8xTT  
//保存下载信息（文件指针位置） l$Vy\CfK3n  
private void write_nPos() A%2B3@1'q  
{ HC}vO0X4  
try{ =;4K5l{c  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1c{m rsB  
output.writeInt(nStartPos.length); 5E]
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for(int i=0;i<nStartPos.length;i++) p+8o'dl8=  
{ @ta:9wZ  
// output.writeLong(nPos); :%z#s  
output.writeLong(fileSplitterFetch.nStartPos); zYP6m3n  
output.writeLong(fileSplitterFetch.nEndPos); \FUMfo^  
} 6J\ 2=c`  
output.close(); }L(ZLt8Q  
} \WBO(,]V  
catch(IOException e){e.printStackTrace ();} Y=4 7se=h"  
catch(Exception e){e.printStackTrace ();} tz8fZ*n  
} 8k3y"239t  
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//读取保存的下载信息（文件指针位置） S6}_N/;6~  
private void read_nPos() '}9 Nvr)+  
{ 7H09\g&  
try{ c:e3hJ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); PZQAlO,  
int nCount = input.readInt(); (uDAdE5  
nStartPos = new long[nCount]; |gWA'O0S  
nEndPos = new long[nCount]; X0iy  
for(int i=0;i<nStartPos.length;i++) !uoT8BBAk  
{ oN[}i6^,e  
nStartPos = input.readLong(); ]tXIe?>9  
nEndPos = input.readLong(); `<|tC#<z  
} 2*<Zc|uNW  
input.close();  ?HRS*  
} "-djA,`  
catch(IOException e){e.printStackTrace ();} Pro?xY$E)  
catch(Exception e){e.printStackTrace ();} %.hJDX\j
 
} up+0-!AH  
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private void processErrorCode(int nErrorCode) PJ;WNo8  
{ 5+11J[~{  
System.err.println("Error Code : " + nErrorCode); 7)]boW~Q  
} AmHj\NX$  
P JATRJ1.  
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//停止文件下载 sQ340!  
public void siteStop() aoZ|@x  
{ g<(!>
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bStop = true; 0VcHz$ 6  
for(int i=0;i<nStartPos.length;i++) "b~C/-W I  
fileSplitterFetch.splitterStop(); }A+ncabm  
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} \c<;!vkZ04  
} rH!sImz,  
//负责部分文件的抓取 V]; i$  
**FileSplitterFetch.java }2@Z{5sh)  
*/
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package NetFox; zzhZ1;\  
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import java.io.*; R;!@ xy  
import java.net.*; \HbZ~I-  
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public class FileSplitterFetch extends Thread { .n1&Jsey  
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String sURL; //File URL ]}PXN1(  
long nStartPos; //File Snippet Start Position pHmqwB~|  
long nEndPos; //File Snippet End Position ;YR/7  
int nThreadID; //Thread's ID Gn=b_!  
boolean bDownOver = false; //Downing is over  NdRcA  
boolean bStop = false; //Stop identical
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FileAccessI fileAccessI = null; //File Access interface e2v`   
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~1D^C |%  
{ 9c[X[Qc  
this.sURL = sURL; W,NqevXo:  
this.nStartPos = nStart; 6`O,mpPu4G  
this.nEndPos = nEnd; L&DjNu`!9  
nThreadID = id; Sc]K-]1(H  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 iq*im$9J  
} F$)l8}  
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public void run() ~*7$aj  
{ E+i*u   
while(nStartPos < nEndPos && !bStop) z'm}p  
{ )][U6
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try{ -$W1wb9z  
URL url = new URL(sURL); '";#v.
!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?).;cG:<  
httpConnection.setRequestProperty("User-Agent","NetFox"); V.&F%(L  
String sProperty = "bytes="+nStartPos+"-"; /Ne#{*z)hO  
httpConnection.setRequestProperty("RANGE",sProperty); GZ~Tl0U  
Utility.log(sProperty); 3T8d?%.l  
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InputStream input = httpConnection.getInputStream(); ySr,HXz  
//logResponseHead(httpConnection); EW*sTI3  
u
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byte[] b = new byte[1024]; ;:D-}t;  
int nRead; ;.uYWP|9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #+1|O;PB#  
{ 3/`BK{  
nStartPos += fileAccessI.write(b,0,nRead); 6 X~><r  
//if(nThreadID == 1) ).;{'8Q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i"}z9Ae~.  
} ]0."{^ksL  
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Utility.log("Thread " + nThreadID + " is over!"); y017 B<Ou  
bDownOver = true; -*' ?D@l  
//nPos = fileAccessI.write (b,0,nRead); 4>=M"DhB  
} BQ0?B*yqd  
catch(Exception e){e.printStackTrace ();} >8_y-74  
} 7A\`  
} ?YW~7zG  
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//打印回应的头信息 bFX{|&tHU  
public void logResponseHead(HttpURLConnection con) KkZx6A)$u  
{ M YF ^zheD  
for(int i=1;;i++) /eQAGFG  
{ p75o1RU  
String header=con.getHeaderFieldKey(i); LZn'+{\`  
if(header!=null) :|s8v2am  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); zG#5lzIu,  
Utility.log(header+" : "+con.getHeaderField(header)); W_2;j)i  
else oRCc8&  
break; 'nq=xi@RC  
} 
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} {!|4JquE_  
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public void splitterStop() ~pRgTXbz  
{ #SHeK 4  
bStop = true; .2fvRN92  
} 7<xnE]jdq  
}qiZ%cT.G  
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} @wcF#?J  
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/* syR"p,3EC  
**FileAccess.java RE;A0E_3  
*//文件访问(定位，写) "#iJ/vy  
package NetFox; }*6BaB  
import java.io.*; =IC.FT}  
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public class FileAccessI implements Serializable{ Y6v{eWtSn  
3^UdB9j;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 r
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RandomAccessFile oSavedFile; Cq2Wpu-u  
long nPos; !1)aie+p6  
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public FileAccessI() throws IOException m;dwt1'Zw  
{ >R F|Q  
this("",0); 2$Mnwxfk  
}
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public FileAccessI(String sName,long nPos) throws IOException =K`.$R  
{ \1<'XVS  
oSavedFile = new RandomAccessFile(sName,"rw"); L0wT:x*  
this.nPos = nPos; W"Ip]LJ  
oSavedFile.seek(nPos); >38>R0k35  
} |R9Lben',  
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public synchronized int write(byte[] b,int nStart,int nLen) zgAU5cw  
{ (GmBv  
int n = -1; ^j\LB23  
try{ h0PDFMM<  
oSavedFile.write(b,nStart,nLen); *9j'@2!M  
n = nLen; z)3TB&;  
} 1q7&WG  
catch(IOException e) L"bJ#0m  
{ |owr?tC  
e.printStackTrace (); EwPrh  
} q|D5 A|)  
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return n; .t@|2  
} t$!zgUJ  
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} ,sL'T[tuiU  
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/* $wUYK%.  
**SiteInfoBean.java ;\RVC7  
*/ c[Fc
3  
package NetFox; _KH91$iW8m  
,R{&x7  
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public class SiteInfoBean { 6^b)Q(Edut  
64/ZfXD  
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private String sSiteURL; //Site's URL *$eH3nn6g  
private String sFilePath; //Saved File's Path _w\9 \<%  
private String sFileName; //Saved File's Name 6eSo.@*l  
private int nSplitter; //Count of Splited Downloading File {W,5]-  
uFWA] ":is  
s%D%c;.|  
public SiteInfoBean() # ?2*I2_  
{//nSplitter的缺省值为5 ]Fy'M  
//default value of nSplitter is 5 (e7!p=D  
this("","","",5); d {!P c<  
} , /.@([C  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %> XsKXj  
{ !K-1tp$
 
sSiteURL= sURL; $nE{%?n-#  
sFilePath = sPath; =0cTct6\  
sFileName = sName; OR@ 67Y  
this.nSplitter = nSpiltter; 9kD#'BxC  
8T3,56>  
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} "|3I|#s  
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public String getSSiteURL() &ivU4rEG  
{ >#
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return sSiteURL; |Rfj 0+  
} G+c&e:ip<  
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public void setSSiteURL(String value) P'<i3#;7X  
{ ` i[26Qb  
sSiteURL = value; 1TZ[i  
} MJ:c";KCq0  
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public String getSFilePath() kZ% AGc  
{ iV{_?f1jo  
return sFilePath; .V;,6Vq
 
} [piK"N  
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public void setSFilePath(String value) JT 7WZc)  
{ j e\!0{  
sFilePath = value; $>/d)o  
} H(^Ehv>  
_`?0w#>0  
:qo[@x{  
public String getSFileName() tiZH;t';<  
{ RE t&QP  
return sFileName; :BxO6@>Xc  
} H1-DK+Q:  
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.B`$hxl*0c  
public void setSFileName(String value) ,kJ'_mq  
{ ,l&?%H9q  
sFileName = value;  P@O_MT  
} =i)%AnZ^9  
\92M\S  
q{9vY:`[  
public int getNSplitter() NO*,}aeG  
{ 8#QT[H 4F  
return nSplitter; sV"tN2W@  
} %wbdg&^  
u(Mbp$R'?  
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public void setNSplitter(int nCount) }%XB*pzQ  
{ 0N1t.3U  
nSplitter = nCount; ,3?=W/Um4  
} "r6qFxY  
} ]>~.U~  
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J^"_H:1[  
/* *9n[#2sM<  
**Utility.java C@-Hm  
*/ =o(}=T>:"  
package NetFox; R,T0!f  
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public class Utility { ;W{z"L;nX  
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8$-MUF,  
public Utility() 6Jgl"Jw8  
{ rRevyT
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8J,^O04<  
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} ]{tWfv|Xg8  
]:f.="  
//线程睡眠 ^?e[$}  
public static void sleep(int nSecond) >.
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{ T]0K4dp+  
try{ Uv59 XF$  
Thread.sleep(nSecond); M.
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} S:!5|o|  
catch(Exception e) z"6o|]9I  
{ lZwjrU| _  
e.printStackTrace (); C 9%bD  
} 7Ydqg&  
} Ow-ejo  
lz=DGm  
//日志 pKLcg"{[F  
public static void log(String sMsg) W<<G  'Km  
{ 6`9QGi,)  
System.err.println(sMsg); pRfKlTU\  
} k[mp(  
Z(:\Vj"  
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public static void log(int sMsg) y1 a%f.F`  
{ zDYJe_m ~  
System.err.println(sMsg); yi^X?E{WnX  
} 7NEOaX(J9  
} azmeJpC  
ydD:6bBX  
]9@4P$I  
/* Rs<S}oeLn  
**TestMethod.java EW]DzL3  
*/ >0kL9_9{  
package NetFox; <2*+Y|Lk2  
23LG)or.JC  
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public class TestMethod { ,JH*l:
7  
#NT~GhWFf  
tln}jpCw  
public TestMethod() 4PSbr$  
{ ///xx/weblogic60b2_win.exe TFbc@rfB  
try{ n}NUe`E_h  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]UOzz1
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); MeD/)T{G~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ft
8  
fileFetch.start(); '!X`X=  
} pz2E+o  
catch(Exception e){e.printStackTrace ();} }Bh\N5G%  
'1!%yKc0  
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} ^p4`o>  
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public static void main(String[] args) }0R"ZPU1Rw  
{ f:q2JgX  
new TestMethod(); \ bNDeA&l  
} zV$Z@o  
} AJ 0Bb7  
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