http断点续传简单实现（java)

/* &56\@t^  
**SiteFileFetch.java =S54p(>  
*/ w@WtW8 p^  
package NetFox; w`boQ_Ir  
import java.io.*; Y_$!XIJ4  
import java.net.*; )LG!"~qiz  
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public class SiteFileFetch extends Thread { oSYJXs  
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SiteInfoBean siteInfoBean = null; //文件信息Bean vKoQ!7g  
long[] nStartPos; //开始位置 ?a+J4Zr3  
long[] nEndPos; //结束位置 [EPRBK`=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3J4OkwqD  
long nFileLength; //文件长度 M| }?5NS  
boolean bFirst = true; //是否第一次取文件 ( q*/=u  
boolean bStop = false; //停止标志 .gNJY7
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File tmpFile; //文件下载的临时信息 HRahBTd(z  
DataOutputStream output; //输出到文件的输出流 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） s#8}&2#l  
public SiteFileFetch(SiteInfoBean bean) throws IOException y1Br4K5C  
{ kazgI>"Q8  
siteInfoBean = bean; }nM+"(}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,|+{C~Ojx  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); t:.X=/02  
if(tmpFile.exists ()) siuDg,uqK5  
{ "OP$n-*@%  
bFirst = false; vG}\Amx+  
read_nPos(); sWA-_4  
} jbOwpyH  
else qoQ,3&<  
{ wMm+E "}W  
nStartPos = new long[bean.getNSplitter()]; &_QD1 TT  
nEndPos = new long[bean.getNSplitter()]; !Y^B{bh  
} bneP>Bd  
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} H5FWk  
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public void run() o9D#d\G  
{ nm|"9|/  
//获得文件长度 IQ#Kod;)  
//分割文件 s?sr0HZ  
//实例FileSplitterFetch ayf;'1  
//启动FileSplitterFetch线程 q|B.@Ng.  
//等待子线程返回 ?6[u\V  
try{ _}H`(d%N  
if(bFirst) !M6Km(>  
{ yaC_r-%U&  
nFileLength = getFileSize(); ->'
q  
if(nFileLength == -1) '}Jq(ah(  
{ ;M#D*<ucI:  
System.err.println("File Length is not known!"); noWwX  
} gU@.IOg  
else if(nFileLength == -2) ~:="o/wo  
{ >
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System.err.println("File is not access!"); >Co@K^'  
} rt! lc-g%/  
else zW95qxXg  
{ 65c#he[_Y  
for(int i=0;i<nStartPos.length;i++) fxD|
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{ Qz A)HDQ
  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); AdF[>Wv  
} TY#pj  
for(int i=0;i<nEndPos.length-1;i++) qy!pD R;  
{ )Vy}oFT\  
nEndPos = nStartPos[i+1]; 6:bvq?5a5  
} xtS0D^  
nEndPos[nEndPos.length-1] = nFileLength; Zg;Ht  
} bu\D*-  
} Wf  *b"#  
wqn}t]  
`t#Ie*  
//启动子线程 4y9n,~Qgw  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; l0wvWv*k  
for(int i=0;i<nStartPos.length;i++) f;W>:`'  
{ BjUz"69  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y-7$HWn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), KMkX0+Ao  
nStartPos,nEndPos,i); 75H5{#)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 03y
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fileSplitterFetch.start(); %lK]m`(  
}  7w|4BRL
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FU(s jB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #w]:<R^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ZsDn
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nEndPos = " + nFileLength); wW;!L=j  
// fileSplitterFetch[nPos.length-1].start(); )Chx,pcx<  
/a
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//等待子线程结束 "IsDL^)A9  
//int count = 0; "(y|iS$^T  
//是否结束while循环 A!5)$>!o  
boolean breakWhile = false; Z}6H529[  
}"9jCxXL  
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while(!bStop) kF*^" Cn  
{
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write_nPos(); BBm;QOBU  
Utility.sleep(500); r \]iw v  
breakWhile = true; wkZ}o,{*:  
8:0.Pi(ln@  
9Lxa?Y1  
for(int i=0;i<nStartPos.length;i++) 8h7z  
{ i
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if(!fileSplitterFetch.bDownOver) :~]ha  
{ ?)#}Nj<R  
breakWhile = false; faaFmEC  
break; >sE{c>R%  
} )0Lv-Gs  
} oBTRO0.s+  
if(breakWhile) fDY#&EO: %  
break; h3Z0NJ=xM  
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//count++; N)Z,/w9  
//if(count>4) k@ZmI^  
// siteStop(); cw{[% 7  
} 6~0.YZ9  
/\M3O  
0/JusQ  
System.err.println("文件下载结束！"); w;Na
9tR  
} [Y]\sF;J  
catch(Exception e){e.printStackTrace ();} U_c.Z{lC4  
} ]`Y;4XR  
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//获得文件长度 hK&/A+*  
public long getFileSize() <$'OSN`!  
{ GoNX\^A  
int nFileLength = -1; ,0=:06l  
try{ "+V.Yue`R  
URL url = new URL(siteInfoBean.getSSiteURL()); &iDX+*(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9n"
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httpConnection.setRequestProperty("User-Agent","NetFox"); thj
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int responseCode=httpConnection.getResponseCode(); @bj3N  
if(responseCode>=400) @t6B\ ?4'T  
{ RE(R5n28,  
processErrorCode(responseCode); &8 ~+^P1w  
return -2; //-2 represent access is error o4CgtqRs  
} |,89zTk'  
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String sHeader; 14p <0BG  
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for(int i=1;;i++) TPrqb  
{ G
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); OXuBtW*,z+  
//Utility.log(in.readLine()); q8{)27f,  
sHeader=httpConnection.getHeaderFieldKey(i); C-abc+/  
if(sHeader!=null) ;X ]+r$_  
{ K$dSg1t  
if(sHeader.equals("Content-Length")) |A#pG^  
{ @e_ bG
@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); j\D_Z{m2  
break; |BGQ|7DyG  
} !giL~}j(R  
} y
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else OFTyN^([@  
break; }Zue?!KQ  
}
I
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} 0
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catch(IOException e){e.printStackTrace ();} p] V  
catch(Exception e){e.printStackTrace ();} [Az<E3H"  
/L8Q[`;.  
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Utility.log(nFileLength); ~e5hfZv|w  
e:E:"elr]  
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return nFileLength; 25RFi24>D  
} 1o. O]>  
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6.| {l8%r  
//保存下载信息（文件指针位置） :O}=$[  
private void write_nPos() ]E\o<"#t/  
{ ao]Dm#HiO  
try{ ua%$r[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); SM2
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output.writeInt(nStartPos.length); P\B ]><!ep  
for(int i=0;i<nStartPos.length;i++) /d*0+m8  
{ F/FUKXxx  
// output.writeLong(nPos); I5l5fx  
output.writeLong(fileSplitterFetch.nStartPos); )DS|mM)  
output.writeLong(fileSplitterFetch.nEndPos); YQWGv,47\  
} )A}u)PH4O  
output.close(); dC$z q~q  
} 6px(]QU  
catch(IOException e){e.printStackTrace ();} RCSG.*%%I  
catch(Exception e){e.printStackTrace ();} 0>?%{Xy  
} d|!FI/  
2HNKq<  
d7.}=E.L  
//读取保存的下载信息（文件指针位置） ^u@"L  
private void read_nPos() {2EIvKu3:  
{ )aov]Ns  
try{ FA}dKE=c Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;by`[)  
int nCount = input.readInt(); V7Z+@e-5  
nStartPos = new long[nCount]; Em?Z  
nEndPos = new long[nCount]; ' XJ>;",[  
for(int i=0;i<nStartPos.length;i++) SW!lSIk  
{ ToWiXH)4
 
nStartPos = input.readLong(); #)&kF+  
nEndPos = input.readLong(); x{_:B DY  
} Ib(q9!L  
input.close(); +>b~nK>M
 
} DlHt#Ob7  
catch(IOException e){e.printStackTrace ();} [ZC{eg+D  
catch(Exception e){e.printStackTrace ();} v803@9@  
} WZ\bm$  
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private void processErrorCode(int nErrorCode) zq1je2DB  
{ &M p??{g  
System.err.println("Error Code : " + nErrorCode); =P}ob eY  
} $l05VZ  
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7>#?-, B  
//停止文件下载 ZG29q>  
public void siteStop() wldv^n hM  
{ >yr:L{{D}G  
bStop = true; } + ]A?'&  
for(int i=0;i<nStartPos.length;i++) HjCWsQM  
fileSplitterFetch.splitterStop(); km@V|"ac _  
vS#Y,H:yAj  
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} 0wM2v[^YO  
} *$K_Tii  
//负责部分文件的抓取 h$p]M^Z7  
**FileSplitterFetch.java ,E8:!r)6  
*/ @d&(*9Y  
package NetFox; UoAHy%Y<%  
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g=)B+SY'  
import java.io.*; %b8ig1  
import java.net.*; 7+_TdDBYs  
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public class FileSplitterFetch extends Thread { `fTH"l1zn  
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'%Cc!63t*  
String sURL; //File URL :1>h,NKC>  
long nStartPos; //File Snippet Start Position ;a"g<v  
long nEndPos; //File Snippet End Position O;zq(/,-l  
int nThreadID; //Thread's ID I5#KLZVg  
boolean bDownOver = false; //Downing is over t zn1|  
boolean bStop = false; //Stop identical ]ySm|&aU  
FileAccessI fileAccessI = null; //File Access interface > 2)@(f~g  
9:DT+^BB  
3K;V3pJ].  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Db:^Omwo  
{ 73Zx`00  
this.sURL = sURL; JWZG)I]r  
this.nStartPos = nStart; =VC"X?
N  
this.nEndPos = nEnd; V{jQ=<)@e  
nThreadID = id; JRti2Mu  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 R[#Np`z  
} {5 V@O_*{  
|7Dc7p"D  
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public void run() eILdq*  
{ tQR qQ  
while(nStartPos < nEndPos && !bStop) hn`yc7<}(u  
{
%mqep5n(  
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 }?eO.l{  
try{ p{@jM  
URL url = new URL(sURL); ?04jkq&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5#275Hyv  
httpConnection.setRequestProperty("User-Agent","NetFox"); W;Y"J_  
String sProperty = "bytes="+nStartPos+"-"; rY?]pMp  
httpConnection.setRequestProperty("RANGE",sProperty); v2Ft=_*G|  
Utility.log(sProperty); s9#WkDR  
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7%j1=V/  
InputStream input = httpConnection.getInputStream(); $jkzm8{W  
//logResponseHead(httpConnection); :@rq+wvP  

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byte[] b = new byte[1024]; Z;ze{Vb  
int nRead; <z.Y#{p?k  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) As{Q9o5j/  
{ e w%rc.;  
nStartPos += fileAccessI.write(b,0,nRead); p>ba6BDJT  
//if(nThreadID == 1) 4h*c{do  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'hGUsi  
} $)YalZ  
"xI70c{  
QLm#7ms*y  
Utility.log("Thread " + nThreadID + " is over!"); ,+P2B%2c  
bDownOver = true; 'G1~ A +  
//nPos = fileAccessI.write (b,0,nRead); R$Rub/b6  
} ;NoiH&  
catch(Exception e){e.printStackTrace ();} 7|@FN7]5NF  
}
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} _^Z v[P  
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7+NBcZuG9  
//打印回应的头信息 @ ^q}.u`  
public void logResponseHead(HttpURLConnection con) T^ )\  
{ <)$e*HrI  
for(int i=1;;i++) 9]L4`.HM  
{ o[aP+O Md  
String header=con.getHeaderFieldKey(i); 9oj#5Hq  
if(header!=null) 9GX'+$R]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); F
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Utility.log(header+" : "+con.getHeaderField(header)); Od("tLIO}I  
else
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break; BCmKzv  
} r1&eA%eh  
} {i<L<Y(3  
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6vfut$)[{  
public void splitterStop() {1"kZL  
{ ~v@.YJoZ4Z  
bStop = true; !59,<N1Iu  
} F05]6NVv  
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} V.e30u5  
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< ZG!w^  
/* \nUJ)w  
**FileAccess.java >:bXw#w
]  
*//文件访问(定位，写) TVZf@U  
package NetFox; ?!.L#]23f  
import java.io.*; % !>@m6JK  
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QQ/9ZI5  
public class FileAccessI implements Serializable{ [Mk:Zz%  
vkLKzsN' ]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6{w'q&LYcE  
RandomAccessFile oSavedFile; \;+TZ1i_  
long nPos; Z817f]l  
N^{}Qvrr  
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public FileAccessI() throws IOException sB*!Nf^y  
{ v'Pbx  
this("",0); Nh01NY;  
} rMoz+{1A  
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54  
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public FileAccessI(String sName,long nPos) throws IOException E#E&z(G2  
{ ^U6VJ(58P  
oSavedFile = new RandomAccessFile(sName,"rw"); A6I^`0/  
this.nPos = nPos; @8Cja.H  
oSavedFile.seek(nPos); <M,<|Y*)  
} kpRk.Q*  
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^)o#/"JA  
public synchronized int write(byte[] b,int nStart,int nLen) k]9y+WC2  
{ o]eG+i6g]  
int n = -1; C{G;G@/7  
try{ Byh!Snoe  
oSavedFile.write(b,nStart,nLen); dG!)<  
n = nLen; dbg%n 0h  
}  e**5_L  
catch(IOException e) _Qq lOc9  
{ v\g1w&PN  
e.printStackTrace (); EeQ2\'t  
} CHVAs9mrNB  
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yBCLS550  
return n; BQ=JZ4&  
} t:P]G>)x|  
f.c2AY~5[  
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} A>frf[fAW  
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/* `Bb32L  
**SiteInfoBean.java ~ %Ij5PD  
*/ Z6
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package NetFox; g77:92  
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public class SiteInfoBean { )=!|^M  
g)}q3-<AK>  
hGI5^!Cq  
private String sSiteURL; //Site's URL k_nQmU>  
private String sFilePath; //Saved File's Path \'&,9lP  
private String sFileName; //Saved File's Name R*H-QH/H1  
private int nSplitter; //Count of Splited Downloading File &srD7v9M8  
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public SiteInfoBean() iM$iZ;Tp
 
{//nSplitter的缺省值为5 k&:~l@?O  
//default value of nSplitter is 5 Y=/;7T  
this("","","",5); I5]58Ohx  
} Qnx?5R-}ZU  
xiVbVr#[  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) KvjH\;
78  
{
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sSiteURL= sURL; dFZh1*1  
sFilePath = sPath; z"*3p8N  
sFileName = sName; _y:aPn  
this.nSplitter = nSpiltter; \okvL2:!  
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} uM[[skc  
EiS2-Uh*TT  
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public String getSSiteURL() ?[.g~DK,  
{ O`_]n  
return sSiteURL; wS [k}  
} 1i#U&  
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/px`FuJI(  
public void setSSiteURL(String value) t'DIKug&  
{ }:\e"Bfv  
sSiteURL = value; F<O<=Ww  
} =%{E^z>1  
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public String getSFilePath() G{.A5{  
{ Hiih$O+  
return sFilePath; $gdGII&n  
} +WvW#wpH  
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public void setSFilePath(String value) JY9hD;`6y  
{ U\q?tvn'J  
sFilePath = value; d3p;[;`  
} D7C%Y^K]>E  
7H. HiyppW  
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public String getSFileName() 85](,YYz  
{ zeuSk|O  
return sFileName; h[]3#  
} lAAPV  
^3nB2G.ax  
6MbMAh5>  
public void setSFileName(String value) OKCX>'j:S  
{ :Ek3]`q#  
sFileName = value; 'D?sRbJ=  
} 2'WdH1UrBc  
Jh%k:TrBm  
9QkIMJf0e  
public int getNSplitter() $]b&3_O$N8  
{ CM+wkU ?,  
return nSplitter; J|b:Zo9<f"  
} >H?~2O  
tmC9p6%  
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public void setNSplitter(int nCount) _LLE~nUK"/  
{ yF1^/y!@  
nSplitter = nCount; |bmc6G[  
} _aOsFFB1KF  
} 9R|B 5.  
.DcuJC=  
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/* 0>0:ls  
**Utility.java (<#Ns W!z  
*/ I`}x9t  
package NetFox; ~wd~57i@  
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public class Utility { hN_,Vyf  
D 3}e{J8  
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public Utility() u=6{
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{ g$S<_$Iey  
U=UnE"
h  
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} LWP&Si*j  
&?7+8n&+  
//线程睡眠 :=%`\\  
public static void sleep(int nSecond) XcQ'(  
{ ,6a }l;lv  
try{ d*<goBd  
Thread.sleep(nSecond); U_e e3KKA  
} +yu^Z*_  
catch(Exception e) |y7#D9m  
{ Jx= v6==7  
e.printStackTrace (); y8\4TjS1  
} V~qlg1h  
} cx(b5Z  

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//日志 UkBr4{+aE  
public static void log(String sMsg) ;hp?wb  
{ H>5@/0cL2  
System.err.println(sMsg); K\>CXa  
} ic|>JX$G  
}g[(h=Qi  
#oD*H:%*  
public static void log(int sMsg) ^k}jPc6  
{ #&c}in"!  
System.err.println(sMsg); }!g^}BWWp  
} <ba+7CK]w  
} u<{uUui}$v  
b."1p7'  
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/* jR&AQ-H&  
**TestMethod.java gL;tyf1P  
*/ r`(U3EgP  
package NetFox; 18U CZ;)>  
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FzGla})  
public class TestMethod { nLjo3yvV..  
h|Uy!?l  
dq ~=P>  
public TestMethod() u.sn"G-c  
{ ///xx/weblogic60b2_win.exe 6~v|pA jY  
try{ /h'b,iYVV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4d0<uB&v'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >T<"fEBI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i&?do{YQ)  
fileFetch.start(); &4O0}ax*Zm  
}
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catch(Exception e){e.printStackTrace ();} :V#W y  

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} 
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public static void main(String[] args) j/xL+Y(=  
{  !(<Yc5  
new TestMethod(); URD<KIN>  
} -3T
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} K)"cwk-  
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