http断点续传简单实现（java)

/* j.[.1G*("  
**SiteFileFetch.java aL\PGdgO  
*/ C!O0xhs  
package NetFox; c`)\Pb/O  
import java.io.*; R+hU8 pu  
import java.net.*; MVpGWTH@F  
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public class SiteFileFetch extends Thread { &C5_g$Ma.Z  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7uqzm  
long[] nStartPos; //开始位置 A;q9rD,_  
long[] nEndPos; //结束位置 3oj' ytxN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 J/`<!$<c  
long nFileLength; //文件长度 YsC>i`n9  
boolean bFirst = true; //是否第一次取文件 ,C\i^>=  
boolean bStop = false; //停止标志 Gq)]s'r2  
File tmpFile; //文件下载的临时信息 #Qw0&kM7I  
DataOutputStream output; //输出到文件的输出流 .fqN|[>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） dZl5Ic  
public SiteFileFetch(SiteInfoBean bean) throws IOException )N{Pw$l_  
{ G{~J|{t\yz  
siteInfoBean = bean; (Bb5?fw  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5X:AbF  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); '`[&}R  
if(tmpFile.exists ()) oi7@s0@  
{ fivw~z|[@  
bFirst = false; nt;m+by  
read_nPos(); 3)wN))VBX  
} b<[Or^X ]  
else *uRBzO}  
{ k!
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nStartPos = new long[bean.getNSplitter()]; n: ^ d|@  
nEndPos = new long[bean.getNSplitter()]; *->W^1eGM  
} dA}-]  
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} ,$L4dF3  
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public void run() *\a4wZ6<3  
{ ah$b[\#C  
//获得文件长度 un"Gozmt5  
//分割文件 #6aW9GO  
//实例FileSplitterFetch 4}baSV  
//启动FileSplitterFetch线程 ?T8}K>a   
//等待子线程返回 +zN-!5x  
try{ IJp-BTO{V  
if(bFirst) dh\'<|\K  
{ G^|:N[>B  
nFileLength = getFileSize(); .[KrlfI  
if(nFileLength == -1) m]0;"jeL  
{ A/$QaB,x  
System.err.println("File Length is not known!"); J$DE"|-  
} ;W )Y OT  
else if(nFileLength == -2) ij`w} V  
{ MTh<|$   
System.err.println("File is not access!"); A0s ZOCky  
} 2eS~/Pq5=i  
else =!A_^;NQf  
{ %g$o/A$  
for(int i=0;i<nStartPos.length;i++) \A#41  
{ Q~]uC2Mw  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); F`W?II?  
} c9 eM/*:  
for(int i=0;i<nEndPos.length-1;i++) Oc0a77@  
{ U[-o> W#  
nEndPos = nStartPos[i+1]; H [\o RId  
} ]L.O8  
nEndPos[nEndPos.length-1] = nFileLength; q'F+OQb1  
} 3AtGy'NTp  
} r.&Vw|*>  
[#vH'y
  
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//启动子线程 ZgcMv,=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; R$<&ie6UQ  
for(int i=0;i<nStartPos.length;i++) ',@3>T**  
{ `:K
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ifQ*,+@fxR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K#d`Hyx  
nStartPos,nEndPos,i); ;?iW%:_,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %3-y[f  
fileSplitterFetch.start(); Np9<:GF1  
} CAWN
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BoWg0*5xb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); dt]-,Y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R4cM%l_#W  
nEndPos = " + nFileLength); Y\k#*\'Y~  
// fileSplitterFetch[nPos.length-1].start(); z'n:@E  
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{$ JYw{a  
//等待子线程结束 *u[BP@vE  
//int count = 0; &)ChQZA  
//是否结束while循环 U(g:zae  
boolean breakWhile = false; Cctu|^V  
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while(!bStop) lT?v^\(H  
{ x~~|.C,  
write_nPos(); wKxtre(v  
Utility.sleep(500); dn
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breakWhile = true; s};{ZAtE  
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for(int i=0;i<nStartPos.length;i++) n
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{ }2.`N%[  
if(!fileSplitterFetch.bDownOver) /nNN,hz  
{ Qn.om=KDs@  
breakWhile = false; 2r?G6D|  
break; K7:)nv E  
} -;m0R  
} q,|j]+
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if(breakWhile) l<LI7Z]A  
break; 6SkaH<-&K  
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//count++; $ @`V  
//if(count>4) .j0$J\:i  
// siteStop(); ChPmX+.i_  
} vMH  
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System.err.println("文件下载结束！"); m8hk:4Ae  
} />pI8 g<  
catch(Exception e){e.printStackTrace ();}  w``ST  
} <)c)%'v  
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//获得文件长度 q ^N7I@Y  
public long getFileSize() :>f )g  
{ )lqAD+9Q  
int nFileLength = -1; #a,PZDaE  
try{ bJ {'<J  
URL url = new URL(siteInfoBean.getSSiteURL()); 9-a0:bP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z
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httpConnection.setRequestProperty("User-Agent","NetFox"); L48_96  
1
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int responseCode=httpConnection.getResponseCode(); $>eCqC3  
if(responseCode>=400)  {Gk1vcq  
{ ZG8DIV\D7  
processErrorCode(responseCode); D.u{~  
return -2; //-2 represent access is error
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} KBc1{adDx@  

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String sHeader; G}raA%  
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for(int i=1;;i++) ,<P vovg_  
{ 4p;`C  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :J&oX <nF^  
//Utility.log(in.readLine()); Ka V8[|Gn,  
sHeader=httpConnection.getHeaderFieldKey(i); #f]SK[nR  
if(sHeader!=null) s-Tv8goNV  
{ ={&j07,*a  
if(sHeader.equals("Content-Length")) H40p86@M  
{ *P=VFP  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); E4/Dr}4  
break; xOmi\VbM  
} mNTzUoZF'@  
} ;'@9[N9  
else ~HsJUro  
break; N5 6g+,w%)  
} }(73Syl#  
} 3;A)W18]  
catch(IOException e){e.printStackTrace ();} SO'vp
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catch(Exception e){e.printStackTrace ();}
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Utility.log(nFileLength); d/kv|$XW  
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return nFileLength; &n:.k}/P  
} =-n}[Y}A  
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//保存下载信息（文件指针位置） GGs}i1m  
private void write_nPos() fr6fj  
{ ;[OH(
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try{ &}B|"s[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); [sjosV  
output.writeInt(nStartPos.length); 4!no~ $b  
for(int i=0;i<nStartPos.length;i++) Q/0Tj]D  
{ 7;wd(8  
// output.writeLong(nPos); `|&O*`  
output.writeLong(fileSplitterFetch.nStartPos); @lrztM
 
output.writeLong(fileSplitterFetch.nEndPos); 
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} :*9Wh  
output.close(); ;iL#7NG-R  
} &d^m 1  
catch(IOException e){e.printStackTrace ();} S;#'M![8  
catch(Exception e){e.printStackTrace ();} Hf2_0wA3  
} RMu~l@  
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//读取保存的下载信息（文件指针位置） s9DYi~/,  
private void read_nPos() g*C7 '  
{ tl^9WG  
try{ }Oq5tC@$G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); vV-`jsq20H  
int nCount = input.readInt(); w%jII{@,  
nStartPos = new long[nCount]; A#iV=76_  
nEndPos = new long[nCount]; ]jp6k<KF  
for(int i=0;i<nStartPos.length;i++) 1K50Z.
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{ Y&Z.2>b
 
nStartPos = input.readLong();
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nEndPos = input.readLong(); e=m42vIB-  
} o`z]|G1''  
input.close(); ?J~_R1Z  
} ^o&. fQ*  
catch(IOException e){e.printStackTrace ();} Z o(rTCZX  
catch(Exception e){e.printStackTrace ();} z5*'{t)  
} u <v7;dF|s  
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private void processErrorCode(int nErrorCode) Ne1$ee.NE  
{ Si;H0uPO  
System.err.println("Error Code : " + nErrorCode); MeZf*' J  
} F0Yd@Lk$_  
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//停止文件下载 "'?>fe\qG  
public void siteStop() ^9:Z7 >Z  
{ 59;KQ  
bStop = true; wgGl[_)  
for(int i=0;i<nStartPos.length;i++) ^WWQI+pk  
fileSplitterFetch.splitterStop(); &7tbI5na@  
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} t&e{_|i#+  
} }a(dyr`S  
//负责部分文件的抓取 <bEbweQrgm  
**FileSplitterFetch.java m GYoM  
*/ k!'a,R:  
package NetFox; #5o(h+w)  
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import java.io.*; oE]QF.n#  
import java.net.*; -]M5wb2,  
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public class FileSplitterFetch extends Thread { _u QOHwn  
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String sURL; //File URL %| Lfuz*  
long nStartPos; //File Snippet Start Position ^SrJu:Q_  
long nEndPos; //File Snippet End Position OYn}5RN  
int nThreadID; //Thread's ID FXkM#}RgNm  
boolean bDownOver = false; //Downing is over > /caXvS  
boolean bStop = false; //Stop identical )bscBj@  
FileAccessI fileAccessI = null; //File Access interface ][Rh28?I{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -m~#Bq  
{ PALc;"]O  
this.sURL = sURL; oe-\ozJ0  
this.nStartPos = nStart; 0oIe>r  
this.nEndPos = nEnd; {;6`_-As%  
nThreadID = id; &6nWzF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~oY^;/ j  
} svH !1b  
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public void run() Qd3 j%(  
{ Wg]Qlw`\|  
while(nStartPos < nEndPos && !bStop) 9CD_os\h  
{ Y`a3tO=Pd  
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try{ 1
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URL url = new URL(sURL); 9~[Y-cpoi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I9ep`X6Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); &gx%b*;`L0  
String sProperty = "bytes="+nStartPos+"-"; Q>i^s@0  
httpConnection.setRequestProperty("RANGE",sProperty); ['iPl/v0  
Utility.log(sProperty); Q hO!Ma]  
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InputStream input = httpConnection.getInputStream(); A6(/;+n  
//logResponseHead(httpConnection); DEZveQr=  
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byte[] b = new byte[1024]; P+/e2Y  
int nRead; tK\~A,=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Ta\tYZj$  
{ '/s)%bc  
nStartPos += fileAccessI.write(b,0,nRead); Jdj4\ju  
//if(nThreadID == 1) [Z$[rOF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #S"nF@   
} *gWwALGo5  
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Utility.log("Thread " + nThreadID + " is over!"); ?gGHj-HYJ  
bDownOver = true; :"/d|i`T  
//nPos = fileAccessI.write (b,0,nRead); $6SW;d+>n  
} R8'RA%O9J  
catch(Exception e){e.printStackTrace ();} _I5Y"o  
} P/_['7  
} j&qub_j"xX  
}*]-jWt1J\  
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//打印回应的头信息 (SAs-  
public void logResponseHead(HttpURLConnection con) [d]9Oa4  
{ 3h`f6  
for(int i=1;;i++) ]~siaiN[  
{ 9XB8VKu8  
String header=con.getHeaderFieldKey(i); {I't]Qj_e  
if(header!=null) nAdf=D'P  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |&i<bqLw:  
Utility.log(header+" : "+con.getHeaderField(header)); {"KMs[M  
else `<d }V2rdz  
break; R (n2A$  
} kE1TP]|  
} }k.Z~1y  
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public void splitterStop() `e}B2;$A3  
{ X!EP$!  
bStop = true; "3Y0`&:D  
} ey$&;1x#5  
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} o?Oc7$+u  
7HYwLG:\~  
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/* +v:SM9  
**FileAccess.java { 2f-8Z&>  
*//文件访问(定位，写) Cq~dp/V  
package NetFox; {E|$8)58i  
import java.io.*; (TT}6j  
\ @2R9,9E  
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public class FileAccessI implements Serializable{ {]4LULq  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 l+0oS'`V*L  
RandomAccessFile oSavedFile; ,Ma^&ypH  
long nPos; j^RmrOg,  
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public FileAccessI() throws IOException [v!f<zSQK  
{ _7_Y={4=`  
this("",0); :?1Dko^  
} 8'y$M] e9n  
0?|<I{z2  
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public FileAccessI(String sName,long nPos) throws IOException wi{3/  
{ O+x!Bg7   
oSavedFile = new RandomAccessFile(sName,"rw"); +X 88;-  
this.nPos = nPos; yyTnL 2Y9  
oSavedFile.seek(nPos); ]u/sphPe  
} G7/ +ogV  
1<aP92/N&  
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public synchronized int write(byte[] b,int nStart,int nLen) }3WxZv]I}  
{ '[%j@PlCX  
int n = -1; cQ}{[YO  
try{ vo{--+{ky!  
oSavedFile.write(b,nStart,nLen); %JTpI`  
n = nLen; 4
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} t\O16O7S  
catch(IOException e) 4Ftu  
{ N!tX<u~2  
e.printStackTrace (); R[+<^s}p/  
} SOao
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return n; )NT*bLRPQ  
} (A.C]hD  
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} ]A_`0"m.U  
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/* 4E}Yt$|  
**SiteInfoBean.java -m
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*/ SUK?z!f<i  
package NetFox; lPAQ3t!,  
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public class SiteInfoBean { buHJB*?9  
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private String sSiteURL; //Site's URL 8
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private String sFilePath; //Saved File's Path [{/jI\?v  
private String sFileName; //Saved File's Name #,'kX
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private int nSplitter; //Count of Splited Downloading File )D%~`,#pQ  
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public SiteInfoBean() )fAUum  
{//nSplitter的缺省值为5 j![\& z  
//default value of nSplitter is 5 F,CTZ~  
this("","","",5); %J-GKpo/S  
} >y+B  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) O^rDHFj,  
{ b|(:[nB  
sSiteURL= sURL; |JsZJ9W+J  
sFilePath = sPath; _,*r_D61S  
sFileName = sName; KqP#6^ _  
this.nSplitter = nSpiltter; `XDl_E+>l  
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} M)(DZ}  
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public String getSSiteURL() + >!;i6|  
{ b\,+f n  
return sSiteURL; tX~w{|k  
} /dIzY0<aO  
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public void setSSiteURL(String value) =-Ck4e *T  
{ 62NsJ<#>  
sSiteURL = value; b#o|6HkW  
} ]/{)bpu  
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public String getSFilePath() iU:cW=W|M\  
{ !bP@n  
return sFilePath; {K!)Ss  
} V28M lP  
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z0Z%m@  
public void setSFilePath(String value) !dT4  
{ !p/goqT~dY  
sFilePath = value; .jK4?}]  
} tT._VK]o&R  
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public String getSFileName() dQG=G%W  
{ \ 6MCxh6  
return sFileName; bhs _9ivw  
} @E8+C8'  
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public void setSFileName(String value) hCo|HB  
{ 4I(Xy]wm  
sFileName = value; O&hTNIfi  
} e~(5%CO>#j  
-7|H}!DFT  
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public int getNSplitter() 7PF%76TO  
{ 51.%;aY~z  
return nSplitter; 8l">cVo]T  
} [.}oyz;}N  
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public void setNSplitter(int nCount) Zgb!E]V[
 
{ P+HXn8@  
nSplitter = nCount; 'we>q@  
} OB}Ib]  
} bQ5\ ]5M  
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&>}5jC.I  
/* I*^Ta{j[  
**Utility.java -DAlRz#d,  
*/ 9Gz=lc[!7  
package NetFox; >5SSQ\2~a  
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public class Utility { Yoll?_k+  
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public Utility() e8b:)"R  
{ Dum9l
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} K"@M,8hb  
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//线程睡眠 eJ81-!)  
public static void sleep(int nSecond) h zn6kbv  
{ Ssg&QI  
try{ YZJyk:H\  
Thread.sleep(nSecond); 9-m=*|p  
} GsM<2@?  
catch(Exception e) 0C,`h`  
{ ,MIV=*  
e.printStackTrace (); 7Fsay+a  
} @9|hMo  
} PeEj&4k  
U,1-A=Og{o  
//日志 ={Qi0Pvt  
public static void log(String sMsg) | VDV<g5h  
{ IO:G1;[/2L  
System.err.println(sMsg); Y\'}a+:@Ph  
} Wh{tZ~c  
%e}Saf  
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public static void log(int sMsg) g< .qUBPKX  
{ Rbv;?'O$L  
System.err.println(sMsg); 
"-V"=t'  
} o#1 $q`Z  
} Eu04e N  
see
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/* LBP`hK:>W~  
**TestMethod.java o*hF<D$Y  
*/ FHI ;)wn=  
package NetFox; ENY+^7  
]5:8Z@  
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public class TestMethod {  %D "I  
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8, >P  
public TestMethod() )whA<lC  
{ ///xx/weblogic60b2_win.exe "kqPmeI  
try{ hP&Bt  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q'MZ R'<@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Kx JqbLUC  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %H"47ZFxAs  
fileFetch.start(); L_i
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} 7. ;3e@s  
catch(Exception e){e.printStackTrace ();} ,$&&-p I]  
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} S|+o-[e8O  
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public static void main(String[] args) .#pU=v#/[  
{ UW EV^ &"x  
new TestMethod(); JqiP>4Uwm^  
} }JAG7L&{  
} 8Uxne2e  
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