http断点续传简单实现（java)

/* SY@;u<Pd  
**SiteFileFetch.java E1w8d4P,G  
*/ 'X4)2iFV  
package NetFox; Oi@|4mo  
import java.io.*; 7@k3-?q  
import java.net.*; U1rr=h g  
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public class SiteFileFetch extends Thread { Rz&}e@stl  
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SiteInfoBean siteInfoBean = null; //文件信息Bean  =Uo*-EH  
long[] nStartPos; //开始位置 utn,`v   
long[] nEndPos; //结束位置 bcxR7<T,"9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,I]]52+?4  
long nFileLength; //文件长度 tqpi{e  
boolean bFirst = true; //是否第一次取文件 0G Q8}r  
boolean bStop = false; //停止标志 6g#E/{kQw  
File tmpFile; //文件下载的临时信息 zF? 6"  
DataOutputStream output; //输出到文件的输出流 iO18FfM_  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <*/Z>Z_c2  
public SiteFileFetch(SiteInfoBean bean) throws IOException  b=Ektq  
{ @LS%uqs  
siteInfoBean = bean; [a~@6*=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3Q7PY46  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7Xh @%[   
if(tmpFile.exists ()) )"2eN3H/  
{ ,4-],~T  
bFirst = false; tuY=)?  
read_nPos(); 9JILK9mVO  
} 8|L5nQ  
else *&+zI$u(  
{ W(-son~I  
nStartPos = new long[bean.getNSplitter()]; e(&u3 #7Nn  
nEndPos = new long[bean.getNSplitter()]; a^[s[j#^,  
} h\~!!F  
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} /V]i3ac  
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public void run() #8BI`.t)j  
{ X_Pbbx_j  
//获得文件长度 z-sq9Qp&x  
//分割文件 GyFA1%(o  
//实例FileSplitterFetch \~U:k4  
//启动FileSplitterFetch线程 e~R_bBQ0  
//等待子线程返回 a6It1%a+  
try{ MFWkJbZV  
if(bFirst) y;P%=MP  
{ V;Ln|._/t  
nFileLength = getFileSize(); [`bK {Dq2  
if(nFileLength == -1) /,$V/q+  
{ %*gg6Q  
System.err.println("File Length is not known!"); |'x"+x   
} N\?__WlBK7  
else if(nFileLength == -2) 0Xn,q]@Z  
{ pDhUD}1G  
System.err.println("File is not access!"); ;DKJ#tS}"  
} 6Tm7|2R  
else )?LZg<<  
{ wCj)@3F  
for(int i=0;i<nStartPos.length;i++) hwi_=-SL  
{ pm[i#V<v  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 66_=bd(9  
} |X6R2
I  
for(int i=0;i<nEndPos.length-1;i++) Rz*GRe
 
{ 6 lEv<)cC  
nEndPos = nStartPos[i+1]; vuJEPn%
 
} AOV{@b(  
nEndPos[nEndPos.length-1] = nFileLength; _?I*:: I  
} P/q] u  
} <R_)[{ 7  
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<w?k<%( 4  
//启动子线程 ;W\?lGOs{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (_gt!i{h  
for(int i=0;i<nStartPos.length;i++) Y\4B2:Qd9  
{ hb}QtQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iYlkc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :<5jlpV(  
nStartPos,nEndPos,i); <HpUP!q8v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ufor>  
fileSplitterFetch.start(); t"MrrK>T  
} P1Iy>%3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r-]%R:U*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w:=:D=xH2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6 Pdao{P  
nEndPos = " + nFileLength); q{f (T\  
// fileSplitterFetch[nPos.length-1].start(); 5as5{"l  
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"\5 T 6  
//等待子线程结束 GsiKL4|mj  
//int count = 0; h1f 05  
//是否结束while循环 Hoe
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boolean breakWhile = false; T;S6<J  
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:1]J{,VG  
while(!bStop) 1v
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{ |PGTP#O
<  
write_nPos(); 95ix~cH3q  
Utility.sleep(500); EDF0q i  
breakWhile = true; .%M8
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for(int i=0;i<nStartPos.length;i++) _E/  
{ 0c,!<\B  
if(!fileSplitterFetch.bDownOver) @
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{ 2a 7"~z~  
breakWhile = false; b+$wx~PLi  
break; ;r.#|b  
} 0eK>QZ_  
} oc[z dIk  
if(breakWhile) {)Shc;Qh  
break;  um2}XI  
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//count++; >Y|P+Z\7  
//if(count>4) by,3A  
// siteStop(); ~|LAe-e"  
} Eb5BJ-XeS^  
l=#b7rBP  
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System.err.println("文件下载结束！"); J?hs\nA  
} -q&,7'V  
catch(Exception e){e.printStackTrace ();} $)6M@S  
} Wo,93]  
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//获得文件长度 TnQW~_:  
public long getFileSize() l701$>>  
{ \vS >jB  
int nFileLength = -1; 
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try{ 2NB$(4/  
URL url = new URL(siteInfoBean.getSSiteURL()); 8CH9&N5W5t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6#
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httpConnection.setRequestProperty("User-Agent","NetFox"); C+dz0u3s  
'X?Iho  
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int responseCode=httpConnection.getResponseCode(); 8;,|z%rS"  
if(responseCode>=400) X `F>kp1  
{ Q"3gvIyc  
processErrorCode(responseCode); O2U}jHsd  
return -2; //-2 represent access is error [EK^0g
 
} X|}Q4T`  
=p:~sn#  
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String sHeader; O]@s`w  
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for(int i=1;;i++) TJZarNc$  
{ _!w69>Nj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9Q7342  
//Utility.log(in.readLine()); Zvr
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sHeader=httpConnection.getHeaderFieldKey(i); u EERNo&  
if(sHeader!=null) +HgyM0LFg  
{ ^SM5
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if(sHeader.equals("Content-Length")) u7 <VD  
{ *uKYrs [  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u_FN'p=.  
break; BQs\!~Ux2  
} !"'6$"U\K  
} t oM+Bd:Y  
else RS@G.|  
break; :u)Qs#'29  
} [*5hx_4%B  
} qt4%=E;[  
catch(IOException e){e.printStackTrace ();} :lK8i{o  
catch(Exception e){e.printStackTrace ();} Mq#Hi9SKY  
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Utility.log(nFileLength); Q:'r p  
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return nFileLength; ,8cVv->u/  
} y k\/Cf  
,kl``w|1M  
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//保存下载信息（文件指针位置） k?1e+ \  
private void write_nPos() y'z9Ya  
{ ?JW/Stua
 
try{ Jid_&\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); o"kL,&  
output.writeInt(nStartPos.length); _lC0XDZ  
for(int i=0;i<nStartPos.length;i++) 2Zg%4/u,Zp  
{ g[\8s~g,  
// output.writeLong(nPos); -"XHN=H  
output.writeLong(fileSplitterFetch.nStartPos); 7|o}m}yVx
 
output.writeLong(fileSplitterFetch.nEndPos); %zhSSB=BJ  
} 3T[zieX  
output.close(); ,vBB". LY'  
} zz8NBO  
catch(IOException e){e.printStackTrace ();} z(#dL>d$'  
catch(Exception e){e.printStackTrace ();} n;~'W*Ln0  
} Qo*OC 9E`  

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//读取保存的下载信息（文件指针位置） o>&-B.zq  
private void read_nPos() +6n\5+5  
{ iP1yy5T  
try{ BL-7r=Z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6_:KFqc W  
int nCount = input.readInt(); def\=WyK  
nStartPos = new long[nCount]; x&$8;2&.  
nEndPos = new long[nCount]; Digx#'#jf  
for(int i=0;i<nStartPos.length;i++) !FvL2L  
{ G+\&8fi0  
nStartPos = input.readLong(); i?|u$[^=+  
nEndPos = input.readLong(); kovJ
9  
} .&h|r>*|J  
input.close(); Sw>,Q-32  
} t@iw&>8z  
catch(IOException e){e.printStackTrace ();} \VypkbE+  
catch(Exception e){e.printStackTrace ();} $yUPua/-  
} NFf`V  

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private void processErrorCode(int nErrorCode) f>m! }F:  
{ #IJ6pg>K  
System.err.println("Error Code : " + nErrorCode); X+/^s)  
} \KKE&3=  
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}*vE/W  
//停止文件下载 ']Z%6_WF  
public void siteStop() kPO+M~+n  
{ w8#ji 1gX  
bStop = true; 162Dj$  
for(int i=0;i<nStartPos.length;i++) UlPGB2B  
fileSplitterFetch.splitterStop(); 3PkU>+.6  
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} =%B}8$.|  
} *o<|^,R  
//负责部分文件的抓取 O>9-iqP>`d  
**FileSplitterFetch.java M} +s_h
9  
*/ 2;w> w#}>  
package NetFox; Ci2*5n<  
lbh7`xCR  
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import java.io.*; (%9J(4  
import java.net.*; zKh<zj  
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public class FileSplitterFetch extends Thread { hI*6f3Vn(n  
'
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String sURL; //File URL TxTxyYd  
long nStartPos; //File Snippet Start Position TiJ \J{  
long nEndPos; //File Snippet End Position gb}ov**  
int nThreadID; //Thread's ID }^*`&Lh  
boolean bDownOver = false; //Downing is over =>O{hT^F  
boolean bStop = false; //Stop identical uX6rCokr  
FileAccessI fileAccessI = null; //File Access interface & sXMB  
sX
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException wBEBj7(y  
{ FMitIM*]   
this.sURL = sURL; 7Oi<_b  
this.nStartPos = nStart; t&IWKu#  
this.nEndPos = nEnd; >;}(?+|f  
nThreadID = id; X9rao n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 KXBTJ&  
} g3Ul'QJ  
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public void run() {yMkd4v  
{ V8Z@y&ny  
while(nStartPos < nEndPos && !bStop) ZbH_h]1$D  
{ j_b/66JyN  
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try{ QJI]@3 Y  
URL url = new URL(sURL); EEvi_Z932  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]
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httpConnection.setRequestProperty("User-Agent","NetFox"); ~h%H;wC&  
String sProperty = "bytes="+nStartPos+"-"; q35=_'\W  
httpConnection.setRequestProperty("RANGE",sProperty); g<:TsP'|  
Utility.log(sProperty); N1U.1~U  
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InputStream input = httpConnection.getInputStream(); <Rz[G+0S=  
//logResponseHead(httpConnection); 7(H?3)%0  
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9MbF:  
byte[] b = new byte[1024]; _6]tbni?v  
int nRead; U?Vik  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) T`c:16I  
{ \t? ;p-+ta  
nStartPos += fileAccessI.write(b,0,nRead); CYM>4C~>JW  
//if(nThreadID == 1) v(,YqT>q@U  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m`4N1egCt  
} q^L"@Q5;  
o ,8;=f,7  
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Utility.log("Thread " + nThreadID + " is over!"); _
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bDownOver = true; q~{O^,4S  
//nPos = fileAccessI.write (b,0,nRead); *]DO3Zw'  
} iZ(JwY  
catch(Exception e){e.printStackTrace ();} 9|K:\!7  
} 0Cyus  
} VI.Cmw~S  
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C @P$RVS  
//打印回应的头信息 -y/Y%]%0  
public void logResponseHead(HttpURLConnection con) T6\d]  
{ Ze?H  
for(int i=1;;i++) }xgs]\^,73  
{  7uzc1}r  
String header=con.getHeaderFieldKey(i); i{r[zA]$  
if(header!=null) Z,>owoP4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (T.j3@Ko  
Utility.log(header+" : "+con.getHeaderField(header)); ixqvX4vv,B  
else |WgFLF~k  
break;  &7eN EA  
} 6?/f$,v  
} =$_kkVQ$  
s|R`$+'{  
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public void splitterStop() ^Jc|d,u;s  
{ 1=^|  
bStop = true; ayN[y  
} LVy (O9g  

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} Z[kVVE9b?  
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/* MQX9BJ%  
**FileAccess.java |"}rC >+  
*//文件访问(定位，写) A|m0.'/  
package NetFox; QjTs$#eMW  
import java.io.*; -r[O_[g w  
:GM3n$  
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public class FileAccessI implements Serializable{ d[p?B-7%  
0.B'Bvn=s2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 m4R:KjN*  
RandomAccessFile oSavedFile; $-39O3  
long nPos; ^+Vf*YY 8  
/^`do3a}  
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public FileAccessI() throws IOException o3le[6C/8=  
{ A=np?
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this("",0); 6L-3cxqf\  
} z AY -Y  
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public FileAccessI(String sName,long nPos) throws IOException +,eF(VS!  
{ 8P} a  
oSavedFile = new RandomAccessFile(sName,"rw"); RuOse9  
this.nPos = nPos; <"7Wb"+  
oSavedFile.seek(nPos); Pe@*')o*  
} >{"E~U  
= @lM*  
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public synchronized int write(byte[] b,int nStart,int nLen) cfHtUv  
{ nDz.61$[  
int n = -1; , ksr%gR+  
try{ 9o
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oSavedFile.write(b,nStart,nLen); RVr5^l;"  
n = nLen; 1\/^X>@W{  
} *tl;0<n  
catch(IOException e) ",S146Y+  
{ ~@"H\):/  
e.printStackTrace (); 5W09>C>OC  
} u_Xp
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return n; 2 yRUw  
} ixB"6O  
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c']m5q39'  
} :{aiw?1  
+O7GgySx  
HzAw rC
  
/* S|m|
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**SiteInfoBean.java sLc,Dx"+  
*/ N <M6~  
package NetFox;  bDq<]h_7  
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public class SiteInfoBean { "
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private String sSiteURL; //Site's URL m=60a@o]  
private String sFilePath; //Saved File's Path g2YE^EKU~  
private String sFileName; //Saved File's Name z#6(PZC}  
private int nSplitter; //Count of Splited Downloading File ,]tMZ?n8  
m-Qy6"eW  
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public SiteInfoBean() r>6FJ:Tx  
{//nSplitter的缺省值为5 P6`LUyz3  
//default value of nSplitter is 5 a._>?rVy  
this("","","",5); vJ>o9:(6  
} ((6?b5[  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) q<cxmo0
S  
{ >oapw5~5  
sSiteURL= sURL; <Kk?BRxi  
sFilePath = sPath; Xc<Hm  
sFileName = sName; !^Q4ZL,-  
this.nSplitter = nSpiltter; ;Ao`yC2(v  
sRC?l_n;  
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} qCm8R@  
5e^z]j1Yv  
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public String getSSiteURL() OUy}1%HY  
{ 96%N  
return sSiteURL; n m.5!.  
} !14l[k+\  
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public void setSSiteURL(String value) 'wo}1^V  
{  X*`b}^T  
sSiteURL = value; 6Z;D`X,5  
} "||' -(0  
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public String getSFilePath() fbJa$  
{ Eg1|Kg\&  
return sFilePath; [=>[2Ty  
} 4H`B]Zt7  
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public void setSFilePath(String value) 5.l
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{ u|(Iu}sE=  
sFilePath = value; jOL=vG  
} lN_b&92  
gj82qy\:  
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public String getSFileName() fBKN?]BdN  
{ (Vt5@25JW  
return sFileName; 4Td)1~zc3  
} )#,a'~w  
h3Nbgxa.  
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public void setSFileName(String value) YOtzja]~  
{ eH%
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sFileName = value; y_T%xWK5  
} h@Ix9!?+  
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n%6=w9.%c  
public int getNSplitter() H^g&e$d0  
{ Vr #o]v  
return nSplitter; 7/dp_I}cO  
} b6'ZVB  
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public void setNSplitter(int nCount) . Fm| $x  
{ q0@b d2}  
nSplitter = nCount; }{.V^;  
} fF.+{-.  
} +B4i,]lCx  
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/* B XO,  
**Utility.java 9/O\769"'  
*/ m [BV{25  
package NetFox; \mw5 ~Rf;  
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Hh%|}*f_,  
public class Utility { |Rb8/WX  
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*\^(-p~M  
public Utility() pK)!o  
{ q[c^`5  
_+ >V(,{G  
_FN#Vq2  
} Qi|k,1A0  
y~wN:  
//线程睡眠 %%lJyLq'Vk  
public static void sleep(int nSecond)
&& WEBQ  
{ r`PD}6\  
try{ +SkfT4*U  
Thread.sleep(nSecond); ePTxuCf>  
} >vNE3S_  
catch(Exception e) $Eo-58<q  
{ s2 $w>L  
e.printStackTrace (); J$,bsMIX  
} ]MB6++.e  
} J n'SGR  
/Y| <0tq  
//日志 zn5|ewl@"  
public static void log(String sMsg) hdYd2 j  
{ YH&0Vy#c$  
System.err.println(sMsg); VRUA<x  
} l^rQo_alk  
Y\E7nll:.  
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public static void log(int sMsg) {%6g6?=j  
{ ,jeC7-tX  
System.err.println(sMsg); <,Jx3yq  
} 24 RD  
} 5]2 p>%G  
Gl9,!"A  
&PFK0tY  
/* _[N*k"  
**TestMethod.java Y$W)JWMY`  
*/ [!`5kI  
package NetFox; 0_-P~^A  
kk}_AZ0eK  
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public class TestMethod { E|_}?>{R  
k!d<2Qp W  
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public TestMethod() igF<].'V  
{ ///xx/weblogic60b2_win.exe 0*6Q8`I  
try{ gN[^ ,u  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Tj!rAMQk  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A&X XL~yH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8*&YQId~  
fileFetch.start(); ,Eo\(j2F.  
} (SByN7[gb  
catch(Exception e){e.printStackTrace ();} J#\oc@  
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yn.[-  
} cuL/y$+EY  
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CM)
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public static void main(String[] args) <>V~  
{ Ka$lNL3<j  
new TestMethod(); s$ ?;C  
} T `o
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} ~gg&G~ET  
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