http断点续传简单实现（java)

/* ,QZNH?Cp/  
**SiteFileFetch.java +*')0I
 
*/ 'k1vV  
package NetFox; |{j\7G*5  
import java.io.*; .}4^b\  
import java.net.*; lI&5.,2MP  
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public class SiteFileFetch extends Thread { ndE"v"_H  
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SiteInfoBean siteInfoBean = null; //文件信息Bean h)o5j-M>4  
long[] nStartPos; //开始位置 G,,7.%eib=  
long[] nEndPos; //结束位置 a?NoNv)&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 iYR`|PJi  
long nFileLength; //文件长度 6z3`*B  
boolean bFirst = true; //是否第一次取文件 }[O/u <Z  
boolean bStop = false; //停止标志 c)q'" r  
File tmpFile; //文件下载的临时信息 -NL=^O$G  
DataOutputStream output; //输出到文件的输出流 y/\0qQ/  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4^uwZ:  
public SiteFileFetch(SiteInfoBean bean) throws IOException )"sJaH
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{ G>?'b  
siteInfoBean = bean; zAA3bgaa  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); i[r>^U8O  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); BHrNDpv  
if(tmpFile.exists ()) kWm[Lt  
{ |-zefzD|  
bFirst = false; ~]S%b3>  
read_nPos(); rIRkXO)  
} s^lm 81;  
else ^a#  
{ C%T$l8$  
nStartPos = new long[bean.getNSplitter()]; CeD(!1VG  
nEndPos = new long[bean.getNSplitter()]; v;$cx*?  
} & Do|
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} j@778fvM\t  
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public void run() .'Rz tBv  
{ ?'%9  
//获得文件长度 sNbCOTow  
//分割文件 f`Wces=5  
//实例FileSplitterFetch YLkdT%  
//启动FileSplitterFetch线程 y|h:{<  
//等待子线程返回 b8~7C4  
try{ 'joE-{  
if(bFirst)  &C&?kS(  
{ &|#z" E^-  
nFileLength = getFileSize(); 34s>hm=0.  
if(nFileLength == -1) hutdw>  
{ hY}.
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System.err.println("File Length is not known!"); ~X2 cTG
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} ov%.+5P  
else if(nFileLength == -2) s{@3G8  
{ ^^+vt8|  
System.err.println("File is not access!"); sA1 XtO<&7  
} em,j>qp  
else ]<<+#Rg  
{ :(Uz`k7   
for(int i=0;i<nStartPos.length;i++) b+!I_g4P  
{ o)SA^5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); S<=
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}  /}&@1  
for(int i=0;i<nEndPos.length-1;i++) oV,lEXz  
{ =!P  
nEndPos = nStartPos[i+1]; fF.qQTy;7  
} oaMh5FPy  
nEndPos[nEndPos.length-1] = nFileLength; D4;6}gRC  
} l>{+X )  
} h$#zuqm  
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//启动子线程 y_A7CG"^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?CHFy2%Y  
for(int i=0;i<nStartPos.length;i++) J]mq|vE  
{ |:G`f8
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $]I",ef  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vm4q1!!(  
nStartPos,nEndPos,i); /Zm5fw9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YdiXj |k+  
fileSplitterFetch.start(); HP G*o  
} g)UYpi?p-}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3X]\p}]z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); d`ESe'j:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6j5?&)xJ  
nEndPos = " + nFileLength); g4=6\vg  
// fileSplitterFetch[nPos.length-1].start(); w?Nx^)xX  
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//等待子线程结束 O({vHqN>  
//int count = 0; MsLQ'9%Au  
//是否结束while循环 t]PO4GA  
boolean breakWhile = false; UCDvN  
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while(!bStop) {H$m1=S  
{ BBUXoz  
write_nPos(); i=DoK{`L  
Utility.sleep(500); \[F4ooe  
breakWhile = true; .pd_SQ~  
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for(int i=0;i<nStartPos.length;i++) 50
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{ Q?"-[6[v  
if(!fileSplitterFetch.bDownOver) XF=GmkO  
{ 53jtwklA  
breakWhile = false; o;<oXv  
break; MF%>avRj  
} wD'LX  
} BR[f{)a5  
if(breakWhile) b*@y/ e\u`  
break; 0"O22<K3a  
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//count++; q9mYhT/Im  
//if(count>4) FMBzTD  
// siteStop(); ~IP3~m D  
} ]'a9>o  
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System.err.println("文件下载结束！"); _m8JU  
} BoMf#l.3B  
catch(Exception e){e.printStackTrace ();} TRSR5D[  
} c7$U0JO  
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//获得文件长度 3kl\W[`?  
public long getFileSize() \hcb~>=C  
{ ;}=[( eqA  
int nFileLength = -1; (HZzA7eph  
try{ V3]"ROH  
URL url = new URL(siteInfoBean.getSSiteURL()); C)Ez>~Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hc4W|Ofj  
httpConnection.setRequestProperty("User-Agent","NetFox"); ND|!U#wMNV  
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int responseCode=httpConnection.getResponseCode(); 1]lm0bfs  
if(responseCode>=400) |(=`l  
{ ]/y&5X  
processErrorCode(responseCode); 3#@ETt0X(  
return -2; //-2 represent access is error &bO0
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} "jy
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String sHeader; c>*RQ4vE  
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for(int i=1;;i++) s)~60c  
{ '[h|f  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^KsiTVY  
//Utility.log(in.readLine()); 5YG?m{hyn_  
sHeader=httpConnection.getHeaderFieldKey(i); f/:XIG  
if(sHeader!=null) Y:0SrB!\  
{ z7H[\4A!>  
if(sHeader.equals("Content-Length")) b6k'`vLA  
{ j+c<0,Kj  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));
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break; TCd1JF0  
} ^BruRgc+  
} ~X/1%  
else `<C/-Au  
break; B0^0d*8t|@  
} B0KZdBRx}  
} 7xOrG],E  
catch(IOException e){e.printStackTrace ();} wER>a (  
catch(Exception e){e.printStackTrace ();} JKkR963 O  
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Utility.log(nFileLength); `.FvuwP  
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return nFileLength; &.Jp,Xt)  
} dfDz/sD*  
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//保存下载信息（文件指针位置） ^]$x/1I;  
private void write_nPos() I]]3=?Y  
{ GB(o)I#h  
try{ A(mU,^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "(hhb>V1Wl  
output.writeInt(nStartPos.length); wnL\.%Y^  
for(int i=0;i<nStartPos.length;i++) 0wLu*K5$4E  
{ d (Fb_  
// output.writeLong(nPos); D! 1oYr  
output.writeLong(fileSplitterFetch.nStartPos); E0<9NFQr7  
output.writeLong(fileSplitterFetch.nEndPos); aMSX"N"ot  
} -
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output.close(); -$E_L:M  
} 8}
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catch(IOException e){e.printStackTrace ();} t]~Lo3  
catch(Exception e){e.printStackTrace ();} `5[d9z/6  
} HXTB
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//读取保存的下载信息（文件指针位置） 3hOiHO ;  
private void read_nPos() DHO6&8S  
{ 9=j"kXFf  
try{ ZkW
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); a{7>7%[  
int nCount = input.readInt(); sS,Swgr  
nStartPos = new long[nCount]; [<Wo7G1s  
nEndPos = new long[nCount]; l
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for(int i=0;i<nStartPos.length;i++) 2Y)3Ue  
{ *7Ct#GC  
nStartPos = input.readLong(); +s:!\(BM  
nEndPos = input.readLong(); -v4kW0G  
} a W`q  
input.close(); _-&\~w  
} ,%#FK|  
catch(IOException e){e.printStackTrace ();} YK/?~p9:  
catch(Exception e){e.printStackTrace ();} 3[E3]]OVa  
} u=h:d+rq@  
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private void processErrorCode(int nErrorCode) TKpka]nJ  
{ njv
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System.err.println("Error Code : " + nErrorCode); F$UvYy4O d  
} ,YYyFMC7S  
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//停止文件下载 wuCiO;w  
public void siteStop() ^[noGjy  
{ 84UH& b'n  
bStop = true; G};os+FxF  
for(int i=0;i<nStartPos.length;i++) +_tK \MN  
fileSplitterFetch.splitterStop(); $R3]y9`?  
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} epsh&)5a*  
} 4=S.U`t7  
//负责部分文件的抓取 .7Zb,r  
**FileSplitterFetch.java lCBb0k2  
*/ cF9bSY_Eh  
package NetFox; Xm./XC  
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import java.io.*; 6eqxwj{S[  
import java.net.*; <(dHh9$~  
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public class FileSplitterFetch extends Thread { _5
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String sURL; //File URL +jePp_3$O  
long nStartPos; //File Snippet Start Position v1Tla]d  
long nEndPos; //File Snippet End Position )$XW~oA'  
int nThreadID; //Thread's ID ld8E!t[  
boolean bDownOver = false; //Downing is over S>isWte  
boolean bStop = false; //Stop identical iB;EV8E  
FileAccessI fileAccessI = null; //File Access interface 7U>Xi'?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException QFMR~6 ?  
{ F!*u}8/_!  
this.sURL = sURL; >58N P1[k  
this.nStartPos = nStart; j+He8w-4  
this.nEndPos = nEnd; pj:s+7"t  
nThreadID = id; K' xN>qc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9P;}P!W  
} S)T]>Ash  
{ O+d7,C  
@
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public void run() r>4HF"Nm  
{ jnfktDV'  
while(nStartPos < nEndPos && !bStop) TbqH-R3W  
{ ^'j? {@  
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try{ ]v&)mK]n=o  
URL url = new URL(sURL); \vj<9ke&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #zflU99d  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1p&e:v  
String sProperty = "bytes="+nStartPos+"-"; ]hNio6CVm  
httpConnection.setRequestProperty("RANGE",sProperty); (}Ob
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Utility.log(sProperty); Y5nj _xQJL  
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InputStream input = httpConnection.getInputStream(); ZbVo<p5* ]  
//logResponseHead(httpConnection); [=k$Q (.3  
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byte[] b = new byte[1024]; S B2R  
int nRead; Fk(nf9M%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \
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{ K
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nStartPos += fileAccessI.write(b,0,nRead); `@%hz%8Y  
//if(nThreadID == 1) G?`{OW3:_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  -D*,*L  
} 8S*3W3HY  
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Utility.log("Thread " + nThreadID + " is over!"); g=*'kj7c3  
bDownOver = true; .SZZT0Z  
//nPos = fileAccessI.write (b,0,nRead); E,u/^V9x  
} h9<*+T  
catch(Exception e){e.printStackTrace ();} /-%0y2"7  
} D d['e  
} \4$V;C/n,  
+i"^"/2f{  
.g/PWEr\I  
//打印回应的头信息 SI_u0j4%*  
public void logResponseHead(HttpURLConnection con) uG-t)pej  
{ vmEbk/Vy  
for(int i=1;;i++) {A<pb{<u  
{ fXNl27c-  
String header=con.getHeaderFieldKey(i); ca )n*SD  
if(header!=null) u^2)oL  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kAc8[Hn  
Utility.log(header+" : "+con.getHeaderField(header)); >6yA+?[:  
else i7rO5<  
break; p;#@#>h  
} \ @XvEx%  
} 4FwtC"G3
 
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public void splitterStop() ckDWY<@v  
{ t`F<lOKj  
bStop = true; >|j8j:S[  
} ^w|D^F=o  
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} Bs?B\k=  
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/* 4~8!3JH39  
**FileAccess.java Dk^,iY(u  
*//文件访问(定位，写) Dx1f<A1  
package NetFox; IOL5p*:gz  
import java.io.*; K/T4T\  
dZ6\2ok+  
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public class FileAccessI implements Serializable{ 9Rf})$o+  
^9_4#Ep(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 tJ3Hg8;  
RandomAccessFile oSavedFile; "}|&eBH^<  
long nPos; +"yt/9AO  
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public FileAccessI() throws IOException ve3-GWT{C  
{ tBB\^xq:  
this("",0); Hl|EySno  
} -F->l5  
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public FileAccessI(String sName,long nPos) throws IOException gdj,e ^  
{  b79z<D  
oSavedFile = new RandomAccessFile(sName,"rw"); g$?kL  
this.nPos = nPos; wC&+nS1  
oSavedFile.seek(nPos); v% c-El%  
} xZE%Gf_U  
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public synchronized int write(byte[] b,int nStart,int nLen) F/ si =%  
{ 5w9oMM{  
int n = -1; PI-o)U$Ehv  
try{ T[(4z@d`5  
oSavedFile.write(b,nStart,nLen); ,qUOPW?=  
n = nLen; 1b``y  
} d,V]j-  
catch(IOException e) RCC~#b
b  
{ bnZ`Wc*5b  
e.printStackTrace (); Au"7w=G`f  
} C@F3iwTtp  
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return n; [&MhAzF  
} -dO9y=?t  
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} o0&pSCK  
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/* zNh$d;(O$^  
**SiteInfoBean.java .dw;b~p  
*/ :k&5Z`>)  
package NetFox; _GtG8ebr  
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public class SiteInfoBean { $T
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private String sSiteURL; //Site's URL y9::m]s  
private String sFilePath; //Saved File's Path gPf^dGi7t  
private String sFileName; //Saved File's Name GiS{=+=5  
private int nSplitter; //Count of Splited Downloading File fa#5pys  
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public SiteInfoBean() wM0P#+bA\  
{//nSplitter的缺省值为5 L9bIdiB7  
//default value of nSplitter is 5 r>kDRIHB  
this("","","",5); Kc#42C;t/  
} IzWS6!zKU  
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LVAnZ'h/|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) iJ%`ym4Y  
{ XJ*W7HD  
sSiteURL= sURL; :ySQ[AJ"  
sFilePath = sPath; F7N4qq1  
sFileName = sName; -guVl4 V  
this.nSplitter = nSpiltter;  Z5[f  
%:=Jr#a  
LQ'VhNU  
} UEh-k"  
WEZ)>[Xj?  
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public String getSSiteURL() k_A 9gj1  
{ 0o*  
return sSiteURL; ;Y"*Z2U  
} f%ynod8  
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n%%u0a%  
public void setSSiteURL(String value) 4K<T_B/  
{ ?6>rQ6tBv  
sSiteURL = value; `mo>~c7  
} 6~y7A<[^  
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:d`8:gv?  
public String getSFilePath() KGq4tlM6  
{ P6([[mmG  
return sFilePath; bR&<vrMmrA  
} F
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)WR*8659e  
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public void setSFilePath(String value) *JmU",X  
{ <Q%:c4N  
sFilePath = value; ?
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} v>]^wH>/"  
N \Wd0b  
W*D].|  
public String getSFileName() ypA)G/;  
{ (g 9G!I   
return sFileName; ckg8x&Z  
} `ek On@T0  
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public void setSFileName(String value) VjhwafYC  
{ AQe~F  
sFileName = value; ja|XFs~  
} "RG #e+  
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public int getNSplitter() .}||!  
{ }5q
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return nSplitter; r")zR,  
} 2xJT!lN  
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$h|rd+},  
public void setNSplitter(int nCount) 8G0DuMI5  
{ TR([u  
nSplitter = nCount; JHCV7$RS  
} zcTY"w\b  
} :1JICxAU  
|}y6U< I  
5NECb4FG  
/* <0hJo=6a8  
**Utility.java uY5Gn.Y  
*/ S.kFs{;1x  
package NetFox; dPfDPb  
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public class Utility { 9&t!U+  
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public Utility() D@yuldx'/  
{ 6qgII~F'  
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->S6S_H/+&  
} ^MZdht   
9+sOSz~ P  
//线程睡眠 k-M-=VvA  
public static void sleep(int nSecond) b[I;6HW  
{ $*u{i4b  
try{ <Gr775"  
Thread.sleep(nSecond); }nW)+  
} ,UD,)ZPf[  
catch(Exception e)
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{ yv!,iK9  
e.printStackTrace (); =>7\s}QZ  
} bCmhlSNi  
} aF'9&A;q  
@$(/6]4p  
//日志 +yYv"J  
public static void log(String sMsg) 8'kA",P  
{ B?xu
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System.err.println(sMsg); ZoiCdXvTN  
}  9g*MBe:  
"w\Iz]  
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public static void log(int sMsg) Je6=N3)  
{ pSq3\#Twr  
System.err.println(sMsg); )n[ oP%  
} GAlAFsB  
} bh8IF,@a  
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/* >Tm|}\qEb  
**TestMethod.java zJfoU*G/B  
*/ TZ7{cekQ  
package NetFox;  t: =  
"lp),  
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public class TestMethod { #6tb{ws3  
ly d[GfJ  
;5P>R[p  
public TestMethod() fQ
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{ ///xx/weblogic60b2_win.exe 3}H"(5dL}z  
try{ FJN,er~T[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); oJk$ +v6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QrP$5H{[E  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 04
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fileFetch.start(); =9 TAs? =  
} \kpk-[W*x{  
catch(Exception e){e.printStackTrace ();} 'xdM>y#S  
R;X8%'  
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} {
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public static void main(String[] args) m4@y58n=  
{ d8b'Gjwtw  
new TestMethod(); fNi&1J-/  
} Hy<4q^3$G  
} ><X!~by  
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