http断点续传简单实现（java)

/* Ly@U\%.  
**SiteFileFetch.java k i~Raa/e  
*/ uOy\{5s8  
package NetFox; :/I={)5  
import java.io.*; "a2H8x  
import java.net.*; Zb5T90s%  
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public class SiteFileFetch extends Thread { DR#3njjEC  

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SiteInfoBean siteInfoBean = null; //文件信息Bean )AZ`R8-A  
long[] nStartPos; //开始位置 Ip1QVND  
long[] nEndPos; //结束位置 2}W6{T'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 0O@[on;Bd  
long nFileLength; //文件长度 CJ37:w{%*Y  
boolean bFirst = true; //是否第一次取文件 n=<q3}1Jej  
boolean bStop = false; //停止标志 ,58kjTM  
File tmpFile; //文件下载的临时信息 'dd<<E  
DataOutputStream output; //输出到文件的输出流 &k {t0>  
5k!(#@a_T  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /0'fcjOaQ  
public SiteFileFetch(SiteInfoBean bean) throws IOException U^W
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{ < :S?t2C  
siteInfoBean = bean; 9 u6 g  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *;~{_Disz  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); lW@
:q04Z$  
if(tmpFile.exists ()) oQE_?">w  
{ |G5=>W  
bFirst = false; Xlgz.j7XR  
read_nPos(); vM$#m1L?  
} LQuYCfj|  
else o>!~*b';g,  
{ 9 ;! uV>-H  
nStartPos = new long[bean.getNSplitter()]; pD)/-Dgdm  
nEndPos = new long[bean.getNSplitter()]; W"DxIy  
} s`dkEaS  
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} a-o hS=W  
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public void run() `^@g2c+d  
{ 6 I>xd  
//获得文件长度 h_}BmJh_  
//分割文件 ?7uStqa  
//实例FileSplitterFetch YV>VA<
c  
//启动FileSplitterFetch线程 ce-m)o/  
//等待子线程返回 !3gpiQH{  
try{ iKCTYXN1(  
if(bFirst) .,(uoK{  
{ c"_H%x<[  
nFileLength = getFileSize(); +RKE|*y  
if(nFileLength == -1) o Q!g!xz  
{
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System.err.println("File Length is not known!"); R&d_WB4w  
} }@t'rK[  
else if(nFileLength == -2) N NXwT0t  
{ pu m9x)y1  
System.err.println("File is not access!");  s`{#[&[  
} +BTNm66Z  
else )l81R  
{ pR^Y|NG!  
for(int i=0;i<nStartPos.length;i++) Xj&~N;Ysb  
{  ;#Bh_f  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4w/t$lR  
} ?F_;~  
for(int i=0;i<nEndPos.length-1;i++) /R+]}Lt~%*  
{ Aghj)V  
nEndPos = nStartPos[i+1]; f1,$<Y|qU  
} _yXeX  
nEndPos[nEndPos.length-1] = nFileLength; 71,0v`Z<  
} smQpIB;  
} jL[Is2<@  
;Bc<u[G  
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//启动子线程 t+Q|l&|0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r z>zdj5}  
for(int i=0;i<nStartPos.length;i++) Y+5A2Z)f[  
{ pOe`*2[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )}g4Rvr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `cTsS  
nStartPos,nEndPos,i); A0 w `o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z[A|SyZp  
fileSplitterFetch.start(); M#gGD-  
} F(kRAe;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 26klW:2*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,,-[P*@  
nEndPos = " + nFileLength); 28L'7  
// fileSplitterFetch[nPos.length-1].start(); 1Z{p[\k  
%emPSBf@  
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//等待子线程结束 bT6)(lm  
//int count = 0; )*AA9   
//是否结束while循环 x;b+gIz*  
boolean breakWhile = false; m"> =QP  
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while(!bStop) U=<.P;+f9  
{ -W"0,.Dvg  
write_nPos(); "a_D]D(d5  
Utility.sleep(500); i1H80m s  
breakWhile = true; F/,<dNJ  
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for(int i=0;i<nStartPos.length;i++) V5^b6$R@  
{ OU964vv  
if(!fileSplitterFetch.bDownOver) >"My\o  
{ 2ZIY{lBe  
breakWhile = false; jm!C
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break; af5`ktx  
} /xbF1@XtL  
} ;.[$  
if(breakWhile) *Z
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break; |~vQ0D  
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//count++; }u*@b10  
//if(count>4) >Ti2E+}[M  
// siteStop(); 
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} Pj5#G0i%  
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System.err.println("文件下载结束！"); g.sV$.T2K  
} ^XB8A=xi  
catch(Exception e){e.printStackTrace ();} Zkep7L   
} :[rKSA]@  
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V# %spW  
//获得文件长度 6G})h!  
public long getFileSize() x;]{ 8#-z  
{ 0\<-R  
int nFileLength = -1; r
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try{ 93eqFCF.  
URL url = new URL(siteInfoBean.getSSiteURL()); L/+J|_J)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]6[d-$#^ko  
httpConnection.setRequestProperty("User-Agent","NetFox"); s5 'nWMo  
5WN Z7cO  
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int responseCode=httpConnection.getResponseCode(); :NyEd<'  
if(responseCode>=400) YD.^\E4o  
{ :|mkI#P.  
processErrorCode(responseCode); :pu{3-n.  
return -2; //-2 represent access is error %hb5C 4q  
} RL)3k8pk  
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String sHeader; @{a-IW3  
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for(int i=1;;i++) TmZ[?IL,  
{ 6(^9D_
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 
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//Utility.log(in.readLine()); 1@dx(_  
sHeader=httpConnection.getHeaderFieldKey(i); \)]2Uh|  
if(sHeader!=null) io'O
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{ Bx!` UdRn  
if(sHeader.equals("Content-Length")) ABDUp:  
{ [1MEA;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); YU,:3{9,  
break; ?7ZlX?D[  
} Y-{BY5E.  
} Czxrn2p/  
else cY]Y8T)  
break; <~*Ol+/  
} j7+t@DqQ  
} vp9<.*h  
catch(IOException e){e.printStackTrace ();} _7.y4zQJ  
catch(Exception e){e.printStackTrace ();} 5hK\YTU  
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Utility.log(nFileLength); oA%[x  
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return nFileLength;  nGd  
} B9-[wg#0G  
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]*U')  
//保存下载信息（文件指针位置） r,KK%B  
private void write_nPos() -y.AJ~T  
{ ~{Bi{aK2  
try{ [![(h %  
output = new DataOutputStream(new FileOutputStream(tmpFile)); A\.*+k/B  
output.writeInt(nStartPos.length); !c($C  
for(int i=0;i<nStartPos.length;i++) f~9Y1|6  
{ $3B?  
// output.writeLong(nPos); ;qK6."b`;  
output.writeLong(fileSplitterFetch.nStartPos); EQ$9IaY.  
output.writeLong(fileSplitterFetch.nEndPos); <]^D({`  
} L:Eb(
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output.close(); PtOnj)Q  
} KHN ,SB  
catch(IOException e){e.printStackTrace ();} }O
  
catch(Exception e){e.printStackTrace ();} ;BVhkWA  
} PlUjjJU  
@/FX7O{n:  
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//读取保存的下载信息（文件指针位置） 3~la/$?p0  
private void read_nPos() Uroj%xN  
{ f|0QN#$  
try{ 4
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;#j82  
int nCount = input.readInt(); ]l%.X7M9  
nStartPos = new long[nCount]; j@!}r|-T  
nEndPos = new long[nCount]; A,)ELVk1F  
for(int i=0;i<nStartPos.length;i++) EPRs%(w`  
{ w\*/(E<:   
nStartPos = input.readLong(); FJ"9Hs2  
nEndPos = input.readLong(); hspg-|R  
} Am  $L  
input.close(); F k;su,]_  
} CF_!{X_k}  
catch(IOException e){e.printStackTrace ();} n#cN[C9  
catch(Exception e){e.printStackTrace ();} qT @IY)e  
} f tDV3If  
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private void processErrorCode(int nErrorCode) I9>*Yy5RNS  
{ q+~CA[H5K  
System.err.println("Error Code : " + nErrorCode); {Z.@-Tl_  
} *xP:7K  
^ni_%`Ag  
n.RhA-O  
//停止文件下载 hh&y2#Io  
public void siteStop() 5zOSb$;  
{ B,,d~\  
bStop = true; >,Z{wxzJ  
for(int i=0;i<nStartPos.length;i++) Ao$z)<d'  
fileSplitterFetch.splitterStop(); DA~ELje^j  
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s  
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} nUHVPuQ/'T  
} w-Fk&dC69  
//负责部分文件的抓取 GR `ncI$z  
**FileSplitterFetch.java 2z3A"HrlA  
*/ f*Js= hvO  
package NetFox; _9r
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import java.io.*; W^Y0>W~  
import java.net.*; ;bE6Y]"Rz  
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public class FileSplitterFetch extends Thread { =U2n"du  
a*ymBGF  
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String sURL; //File URL V"iLeC  
long nStartPos; //File Snippet Start Position *'-^R9dN.S  
long nEndPos; //File Snippet End Position +to9].O7y  
int nThreadID; //Thread's ID 8 GN{*Hg  
boolean bDownOver = false; //Downing is over F9r*ZyNlx  
boolean bStop = false; //Stop identical vy2aNUmt  
FileAccessI fileAccessI = null; //File Access interface ZQA C&:  
5&=n  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
?Nql7F4  
{ m
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this.sURL = sURL; U:hC!t:  
this.nStartPos = nStart; " SqKS,J  
this.nEndPos = nEnd; 7!wnx.  
nThreadID = id; . *xq =  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0u2uYiE-l  
} yVzg<%CR^  
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public void run() #SNI dc>9\  
{ vyGLn  
while(nStartPos < nEndPos && !bStop) *PU,Rc()6  
{ uiA:(2AQ  
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try{ 4LJ}>e  
URL url = new URL(sURL); X{9o8 *V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /j@ `aG(a  
httpConnection.setRequestProperty("User-Agent","NetFox"); !5t 3Y  
String sProperty = "bytes="+nStartPos+"-"; 4{t$M}?N  
httpConnection.setRequestProperty("RANGE",sProperty); 2tm-:CPG  
Utility.log(sProperty); tuV?:g?  
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InputStream input = httpConnection.getInputStream(); Wb
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//logResponseHead(httpConnection); 5>Yd\(`K  
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byte[] b = new byte[1024]; N~_jiVD>  
int nRead; Cbs4`D
,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?^4sE-C6  
{ IkNt! 2s_  
nStartPos += fileAccessI.write(b,0,nRead); uA`PZ|  
//if(nThreadID == 1) ER1mA:8>E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q.dy $`\  
} N==_'`O1Q0  
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Utility.log("Thread " + nThreadID + " is over!"); dU3>h[q  
bDownOver = true; 8;&S9'ci  
//nPos = fileAccessI.write (b,0,nRead); _rdj,F8  
}
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catch(Exception e){e.printStackTrace ();} Am0C|(#Xm  
} q*TKs#3  
} Ab<Ok\e5  
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//打印回应的头信息 F>(#Af9  
public void logResponseHead(HttpURLConnection con) BG0Mj2  
{ v/.h%6n?  
for(int i=1;;i++) &})d%*n  
{ U*"cf>dB(  
String header=con.getHeaderFieldKey(i); vD9D:vK  
if(header!=null) 05I39/T%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); A=
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Utility.log(header+" : "+con.getHeaderField(header)); 810<1NP  
else 3N0X?* (x|  
break; E?4@C"Na  
}
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} <;E[)tv  
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- zw{<+;  
public void splitterStop() Cf=q_\0|W  
{ TM}'XZ&  
bStop = true; ?iEXFYJG  
} dN/ "1%9)  
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} yZ)aKwj%U  
b\j&!_   
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/* VN-#R=D  
**FileAccess.java aevG<|qP  
*//文件访问(定位，写) 3]OP9!\6  
package NetFox; bNpIC/#0K  
import java.io.*; 'L|GClc6)
 
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public class FileAccessI implements Serializable{ ])j|<W/  
\M"^Oe{Dy?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X>Xp&o  
RandomAccessFile oSavedFile;  QXxLe*  
long nPos; jvc?hUcLKT  
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' raB  
public FileAccessI() throws IOException ;(0(8G  
{ ^HlLj#  
this("",0); %*
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} 6
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public FileAccessI(String sName,long nPos) throws IOException ^A"lkV7  
{ KWhM  
oSavedFile = new RandomAccessFile(sName,"rw"); u ?G\b{$m  
this.nPos = nPos; 'W?v.W &  
oSavedFile.seek(nPos); JQ/t, v$G  
} [[0bhmG)  
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"^ 6lvZP(  
public synchronized int write(byte[] b,int nStart,int nLen) Ce5w0&VlS  
{ hi3sOK*r;<  
int n = -1; O? Gl4_y  
try{ <[y$D=n  
oSavedFile.write(b,nStart,nLen); $]H=  
n = nLen; hLytKPgt  
} :ONuWNY N  
catch(IOException e) bxhg*A  
{ 2
^ ,H_PS  
e.printStackTrace (); <{NYD.  
} h-b5   
h/X5w4  
)
}Rfa}MD  
return n; ,P@/=I5  
} $D/bU lFx  
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} .qIy7_^  
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2l)9Lz=;L  
/* 7edPH3  
**SiteInfoBean.java G_^iR-
  
*/ ^YG7dd_  
package NetFox; 5&?KW)6 Rz  
(3N"oE.b]  
.A*VLF*m  
public class SiteInfoBean { ia^%Wg7  
5qd_>UHp  
XYb^Cs;  
private String sSiteURL; //Site's URL KZrMf77=  
private String sFilePath; //Saved File's Path iF [?uF  
private String sFileName; //Saved File's Name 4z9#M;qT  
private int nSplitter; //Count of Splited Downloading File c:ll
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=CjNtD2]  
z;y^t4 ^9  
public SiteInfoBean() YXX36  
{//nSplitter的缺省值为5 J+71FP`ZH  
//default value of nSplitter is 5 &SjHrOG?  
this("","","",5); .|-l+  
} S$jV|xKB  
<}EV*`w4  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -Wlp=#9  
{ ]>)u+
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sSiteURL= sURL; C(V[wvL  
sFilePath = sPath; qY$*#*Q
  
sFileName = sName; z/Ns5  
this.nSplitter = nSpiltter; M[YTk=IM#  
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*2,e=tY>  
} ^"O{o8l>2  
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public String getSSiteURL() 11)/] ?/j  
{ %NT`C9][  
return sSiteURL; 4d^ \l!  
} K\IYx|Hm a  
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8_a$kJJ2  
public void setSSiteURL(String value) AV:Xg4UJv  
{ %@}o'=[  
sSiteURL = value; GOy=p3mQ  
} *xE"8pN/  
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public String getSFilePath() ""1#bs{n  
{ -?< Ww{  
return sFilePath; hWD !  
} 1R=)17'O  
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public void setSFilePath(String value) &1
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{ oA4D\rn8"  
sFilePath = value; $!YKZ0)B'0  
} 0'?V|V=v  
vKNt$]p
m=  
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public String getSFileName()  4%g6_KB  
{ P%zH>K  
return sFileName; {&2$[g=[ ^  
} =X-^YG3x  
vk @%R  
1.# |QX  
public void setSFileName(String value) 8tb6 gZz  
{ yicO!:bM  
sFileName = value; )Y3EQxXa  
} ([:]T$0 #  

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I jZ]_*^!  
public int getNSplitter() $_Y/'IN`k  
{ -1qZqU$h  
return nSplitter; qqncl
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} hi!L\yi  
m7$8k@r  
A2m_q>> !  
public void setNSplitter(int nCount) ^"3\iA:  
{ .z=U= _e  
nSplitter = nCount; weNzYMf%  
} "pt+Fe|@c;  
} Dt.0YKF  
16"#i  
6!P`XTTE  
/* yiiyqL*E  
**Utility.java Ne3R.g9;Z  
*/ Lltc4Mzw  
package NetFox; A0G)imsW:_  
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public class Utility { 41u*w2j  
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public Utility() !Citzor  
{ Ls&+XlrX8  
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} _eGT2,D5r  
R)ERxz#  
//线程睡眠 w{pUUo:<  
public static void sleep(int nSecond) <lUOJV{&\  
{ _`H.h6h  
try{ >DHp*$y  
Thread.sleep(nSecond); dXmV@ Noo  
} ))!Bg?t-  
catch(Exception e) #Mh{<gk%ax  
{ Rj^7#,993  
e.printStackTrace (); t)` p@]j  
} m9Ax\lf  
} 7_-w_"X  
0axxQ!Ivx  
//日志 q#MM
  
public static void log(String sMsg) !lAD q|$  
{ gw"
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System.err.println(sMsg); dm6~  
} |'tW=  
"NDxgJ%J35  
X 7=fX~s  
public static void log(int sMsg) cB#nsu>  
{ 'Y.Vn P&H  
System.err.println(sMsg); []|;qHhC~(  
} syv$XeG=}  
} x[QZ@rGIW  
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/* SyO79e*t  
**TestMethod.java h{k_6ym  
*/ h4/X 0@l`  
package NetFox; tAjx\7IX  
b.b@bq$1  
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public class TestMethod { CswE  
in<}fAro6  
yPV'pT)  
public TestMethod() P-CB;\  
{ ///xx/weblogic60b2_win.exe '_dzcN,z  
try{ K$H <}e3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); piOXo=9H.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); m 41t(i  
SiteFileFetch fileFetch = new SiteFileFetch(bean); p~2UUmV  
fileFetch.start(); ;#TaZN  
} l?
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catch(Exception e){e.printStackTrace ();} 6"U8V?E  
-I":Z2.fR  
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} 3NIUW!gr  
+R6a}d/K  
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public static void main(String[] args) ,LZX@'5  
{ =p@8z /u  
new TestMethod(); ;Wc4qJ.@  
} (vc|7DX M  
} iEIg
:  
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