http断点续传简单实现（java)

/* .4^+q9M  
**SiteFileFetch.java pL1ABvBB  
*/ f;^ +q-Q  
package NetFox; x3cjyu<K  
import java.io.*; FzX ;~CA  
import java.net.*; %]}JWXof  
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public class SiteFileFetch extends Thread { GP c B(  
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SiteInfoBean siteInfoBean = null; //文件信息Bean fX`u"`o5  
long[] nStartPos; //开始位置 AuQ|CXG-\  
long[] nEndPos; //结束位置 4Y?2u  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 R 9`[C  
long nFileLength; //文件长度 zN!W_2W*  
boolean bFirst = true; //是否第一次取文件 + )Qu,%2   
boolean bStop = false; //停止标志 _">F]ptI;  
File tmpFile; //文件下载的临时信息 YCiG~y/~  
DataOutputStream output; //输出到文件的输出流 ((A@VcX  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） b5)^g+8)w  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q,5PscE6&k  
{ _C5i\Y
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siteInfoBean = bean; %>Gb]dv?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :4V5p =v-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9<?w9D.1  
if(tmpFile.exists ()) UCc
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{ @>O7/d?O  
bFirst = false; [T r7SU#x  
read_nPos(); "'[M~Js  
} s`=| D'G(=  
else 8<;.  
{ zK~8@{l}_"  
nStartPos = new long[bean.getNSplitter()]; 3R<r[3WP  
nEndPos = new long[bean.getNSplitter()]; ;GM`=M4  
} )1Bz0:  
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} -lJ|x>PG'  
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public void run() HDKF>S_S  
{ mbbhz,  
//获得文件长度 0bh 6ay4  
//分割文件 r5s{t4 ;Ch  
//实例FileSplitterFetch -Ct+W;2  
//启动FileSplitterFetch线程 c9[{P~y  
//等待子线程返回 T3oFgzoO  
try{ e=VSO!(rY  
if(bFirst) A x8>  
{ >I@&"&d  
nFileLength = getFileSize(); Q.$8>)  
if(nFileLength == -1) R?)Yh.vi=t  
{ OE(y$+L3_I  
System.err.println("File Length is not known!"); D Z*c.|W  
} /E<Q_/'Z  
else if(nFileLength == -2) 9e`};DE   
{ aQ(P#n>a2  
System.err.println("File is not access!"); d3rjj4N"z  
} aU;X&g+_)  
else S*G^U1Sc+  
{ E|9`J00  
for(int i=0;i<nStartPos.length;i++) i}8OaX3x  
{ (.N n|lY<i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 12#yHsk  
} @lDnD%vZ`  
for(int i=0;i<nEndPos.length-1;i++) n>u_>2Ikkj  
{ <!
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nEndPos = nStartPos[i+1]; <7`k[~)VB  
} 0"e["q{|  
nEndPos[nEndPos.length-1] = nFileLength; p
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} >6Pe~J5,:  
} EgG3XhfS  
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//启动子线程 +Iuu8t  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; A v>v\ :.>  
for(int i=0;i<nStartPos.length;i++) %G(VYCeK  
{ uSXnf  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RDSC@3%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), EFDmNud`Q  
nStartPos,nEndPos,i); [@qjy*5p  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $A~aNI  
fileSplitterFetch.start(); -`5]%.E&8  
} Mo3%OR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [gUD +  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |s/Kb]t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", r(wf>w3  
nEndPos = " + nFileLength); 40=u/\/K  
// fileSplitterFetch[nPos.length-1].start(); O\Y*s  
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//等待子线程结束 1ik.|T<f0  
//int count = 0; &I ~'2mpk  
//是否结束while循环 ;rL>{UhG  
boolean breakWhile = false; ?;Sg,.J  
IY.M#Q]  
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while(!bStop) /Zs_G=\>  
{ p}==aNZK  
write_nPos(); "a;$uW@.6  
Utility.sleep(500); O6$,J12l  
breakWhile = true; S^~"#  
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for(int i=0;i<nStartPos.length;i++) l$!ExXEZO;  
{ K+/wJ9^B  
if(!fileSplitterFetch.bDownOver) fCu;n%   
{ /NB|N*}O)  
breakWhile = false; l@w\ Vxr  
break; Tr>_R%bK  
} O=}  
}
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if(breakWhile) 93Gj#Mk  
break; ? .B t.  
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//count++; hB<(~L?A]  
//if(count>4) ghW`xm87  
// siteStop(); _)pOkS  
} +Goh`!$Rj9  
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System.err.println("文件下载结束！"); LsGO~EiJ  
} 3`D*AFQc  
catch(Exception e){e.printStackTrace ();} Vq#0MY)2gS  
} a"
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//获得文件长度 bRFZ:hu l  
public long getFileSize() J s33S)  
{ 1:7fV@jw  
int nFileLength = -1; d$\n@}8eZp  
try{ OPUrz?p2C  
URL url = new URL(siteInfoBean.getSSiteURL()); {gEz;:!):  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l(Qnt
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httpConnection.setRequestProperty("User-Agent","NetFox"); (i{ZxWW&  
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int responseCode=httpConnection.getResponseCode(); 7^.g\Kt?  
if(responseCode>=400) j?t
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{ +5O^{Ce6  
processErrorCode(responseCode); $pP
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return -2; //-2 represent access is error &)q>Z!C-l  
} ^Hf?["m^@  
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, DuyPBAms  
String sHeader; W4qT]m  
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for(int i=1;;i++) ulg=,+%r  
{ yN[i6oe  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); qOD^P  
//Utility.log(in.readLine()); w=nS*Qy2  
sHeader=httpConnection.getHeaderFieldKey(i); YJz06E1 -9  
if(sHeader!=null) !6taOT>v  
{ H
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if(sHeader.equals("Content-Length")) ZBK)rmhMx  
{ @~=d4Wj6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); FS)C<T]t  
break; 8rBa}v9  
} &-IkM%_A9  
} NU.4_cixb  
else asvM/9  
break; 3# 0Nd"/0  
} u&`rK7J  
} F6DVq8f9  
catch(IOException e){e.printStackTrace ();} d@ZXCiA},  
catch(Exception e){e.printStackTrace ();} /55 3v;l<  
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Utility.log(nFileLength); ;l `(1Q/  
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return nFileLength; ?` ebi|6  
} 1,P2}mYv  
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//保存下载信息（文件指针位置） xOxyz6B\  
private void write_nPos() LDo~  
{ )ARV>(  
try{ rV%;d[LB  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ki`ur%h  
output.writeInt(nStartPos.length); './qBJ  
for(int i=0;i<nStartPos.length;i++) $Vs5d=
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{ ~O/B  
// output.writeLong(nPos); ? R[GSS1  
output.writeLong(fileSplitterFetch.nStartPos); }*P;kV  
output.writeLong(fileSplitterFetch.nEndPos); ucLh|}jJ5  
} R6GlQ G
 
output.close(); bV)h\:oC  
} ey>tUmt6?  
catch(IOException e){e.printStackTrace ();} L?(1 [jB4G  
catch(Exception e){e.printStackTrace ();} cE,,9M@^  
} |BbrB[+ v[  
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//读取保存的下载信息（文件指针位置） 68qCY  
private void read_nPos() ,0,& L  
{ q+4<"b+6G  
try{ S6yLq|W0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Hs.5@l  
int nCount = input.readInt(); ,I f9w$(z  
nStartPos = new long[nCount]; W\ARCcTQ  
nEndPos = new long[nCount]; 'A/{7*,  
for(int i=0;i<nStartPos.length;i++) Co<F<eXe  
{ B]#iZ,Tp  
nStartPos = input.readLong(); #@M'*X_%}K  
nEndPos = input.readLong(); 51s3hX$  
} dlV HyCW  
input.close(); y.Yni*xt/  
} !1+!;R@&H>  
catch(IOException e){e.printStackTrace ();} G>2: WQ/  
catch(Exception e){e.printStackTrace ();} 'Hq#9?<2M  
} $4CsiZ6  
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private void processErrorCode(int nErrorCode) S }G3ha  
{ 1[?xf4EMG  
System.err.println("Error Code : " + nErrorCode); bFIv}c+;  
} <5c^DA  
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p!LaR.8]  
//停止文件下载 u&Xn#fh  
public void siteStop() a/q8vP  
{ v`"BXSmp{  
bStop = true; u9}LvQh_6,  
for(int i=0;i<nStartPos.length;i++) #|cr
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fileSplitterFetch.splitterStop(); G'_5UP!  
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} 1u~.^O}J  
} {*qz<U>  
//负责部分文件的抓取 m&6I@S2  
**FileSplitterFetch.java &,=t2_n  
*/ Wl>$<D4mO[  
package NetFox; 9>L{K   
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import java.io.*; .t%`"C  
import java.net.*; <:0d%YB)  
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}/-TT0*6j<  
public class FileSplitterFetch extends Thread { 0\Myhh~DLE  
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String sURL; //File URL Dj{t[z]$k  
long nStartPos; //File Snippet Start Position S6|L !pO  
long nEndPos; //File Snippet End Position Ha!]*wg#  
int nThreadID; //Thread's ID X;p4/ *U  
boolean bDownOver = false; //Downing is over 8:Jc2K  
boolean bStop = false; //Stop identical ')v<MqBr  
FileAccessI fileAccessI = null; //File Access interface 6[C>"s}Ol  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 
( |Xc_nC  
{ ?pp|~A)b  
this.sURL = sURL; -*"Q-GO  
this.nStartPos = nStart; %VzCeS9  
this.nEndPos = nEnd; JKYkS*.a}  
nThreadID = id; *}NJ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 gl"1;C  
} ~f!iz~  
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public void run() JdA3O{mT)  
{ e^Lt{/  
while(nStartPos < nEndPos && !bStop) gPM<LO`;i  
{ 8G p%Q  
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try{ 0
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URL url = new URL(sURL); 7S]akcT/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ejPK-jxCa/  
httpConnection.setRequestProperty("User-Agent","NetFox"); )3KQ QGi8  
String sProperty = "bytes="+nStartPos+"-"; "DNiVL.  
httpConnection.setRequestProperty("RANGE",sProperty); yBwCFn.uP-  
Utility.log(sProperty); Nm=\~LP90  
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InputStream input = httpConnection.getInputStream(); g6T /k7a  
//logResponseHead(httpConnection); g_t1(g*s  
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byte[] b = new byte[1024]; _0]{kB.$_  
int nRead; B[6y2+6$0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .6nNqGua1  
{ i\u m;\  
nStartPos += fileAccessI.write(b,0,nRead); cv/  
//if(nThreadID == 1) _^pg!j[Fy}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =M+enSu  
} zkRL'-  
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Utility.log("Thread " + nThreadID + " is over!"); (#;<iu}  
bDownOver = true; $j!VJGVG  
//nPos = fileAccessI.write (b,0,nRead); 7IH^5r  
} ZI'Mr:z4  
catch(Exception e){e.printStackTrace ();} an9k2F.)  
} ~kAen  
} \a6knd  
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//打印回应的头信息 e^ygQ<6%  
public void logResponseHead(HttpURLConnection con) }28,fb /  
{ ROB/#Td  
for(int i=1;;i++) 4chSo.= 4V  
{ KD5}Nk)t  
String header=con.getHeaderFieldKey(i); }vLK-Vv  
if(header!=null) 3d@$iAw1<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); O*7Gl G  
Utility.log(header+" : "+con.getHeaderField(header)); /_G^d1T1?L  
else #RwqEZ  
break; ?u]%T]W  
} e)2
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} QjlwT2o'  
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public void splitterStop() g5*Zg_G/  
{ M4:}`p=  
bStop = true; V=,VOw4  
} ,3`RM$  
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} _jW}p-j  
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/* m pWmExQ  
**FileAccess.java K8UgP?c;0  
*//文件访问(定位，写) elBmF#,j7  
package NetFox; _g(4-\  
import java.io.*; &_EjP hZ  
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public class FileAccessI implements Serializable{ aT %A<'O!  
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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[Dr[  
RandomAccessFile oSavedFile; FM3DJ?\L-  
long nPos; J c~{ E  
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public FileAccessI() throws IOException {u}Lhv  
{
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this("",0); V@
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} Nuw_,-h  
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public FileAccessI(String sName,long nPos) throws IOException uZ-yu|1  
{ 6-@ X  
oSavedFile = new RandomAccessFile(sName,"rw"); Y!6,ty'  
this.nPos = nPos; ]~SOGAFW  
oSavedFile.seek(nPos); JPX5Jm()  
} *@|EaH/  
:Sx!jx>W  
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public synchronized int write(byte[] b,int nStart,int nLen) #UcqKq  
{ +([ iCL  
int n = -1; CmNd0S4v  
try{ NiwJ$Ah~X  
oSavedFile.write(b,nStart,nLen); #O<2wMb2<  
n = nLen; gt9{u"o  
} luyU!  
catch(IOException e) 6Y|jK<n?H  
{ ",\,lqV  
e.printStackTrace ();
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} FBYAd@="2  
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return n; z#8d\X/  
}  ;Q;u^T`  
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} c8cV{}7Kb  
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/* wsyG~^>  
**SiteInfoBean.java  6[<*C?  
*/ /N`l z>^~  
package NetFox; S?W!bkfn  
G &'eP  
LeA=*+zP[  
public class SiteInfoBean {
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@?A39G{  
private String sSiteURL; //Site's URL f3>8ZB4  
private String sFilePath; //Saved File's Path f#RI&I\  
private String sFileName; //Saved File's Name Mt@
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private int nSplitter; //Count of Splited Downloading File ?d*0-mhQ,  
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public SiteInfoBean() ?qeBgkL(B^  
{//nSplitter的缺省值为5 Md9b_&'  
//default value of nSplitter is 5 smpz/1U  
this("","","",5); :&#HrD[KT  
} v(vLk\K7  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) vV.TK_y  
{ >g%^hjJ  
sSiteURL= sURL; u.wm;eK[  
sFilePath = sPath; GbC-6.~  
sFileName = sName; &j\<UPn  
this.nSplitter = nSpiltter; =#@eD
m%  
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} A4,tv#z  
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} PD]e*z{Z  
public String getSSiteURL() "p43#  
{ ESk<*-  
return sSiteURL; o0Z(BTO  
} +?[,y  
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public void setSSiteURL(String value) x&6SjlDb$K  
{ (vCMff/ Y1  
sSiteURL = value; B
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} \bze-|C  
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public String getSFilePath() 6N}>@Y5  
{ pKf]&?FX
 
return sFilePath; |kwBb>V  
}
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V6.xp{[  
public void setSFilePath(String value) 3:Aw.-,i\  
{ pA(B~9WQ  
sFilePath = value; \#P>k;D  
}  D(}w$hi8  
Y<U"}}  
e
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public String getSFileName() 3/P#2&jt  
{ z~TG~_s  
return sFileName; ;P9P2&c8c  
} KdT1Nb=  
9o<}*L  
sd;J(<Ofh  
public void setSFileName(String value) &Q>)3]|p  
{ GY@-}p~it  
sFileName = value; ;b=3iT-2"  
} 8}/v[8p  
E5d?toZ,8"  
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public int getNSplitter() G.2ij%Zz  
{ <}~`YU>=v  
return nSplitter; !`8WNY?K  
} #}
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public void setNSplitter(int nCount) \\80c65-  
{ }cK<2J#  
nSplitter = nCount; .\kcWeC\  
} 2BLcun  
} 7\sJ=*  
`=A*ei5  
c+l1#[Dnc  
/* DPuz'e*  
**Utility.java _qg)^M6  
*/ *={` %  
package NetFox; x0^O?UR  
x!klnpGp  
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public class Utility { ]C|Zs=5  
#%CbZw@hJ9  
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public Utility() {@1C,8n;  
{ OR[6pr@  
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808E)  
} ,3_;JT"5  
R:zPU   
//线程睡眠 n:zoN2lC  
public static void sleep(int nSecond) )i&z!|/2  
{ +I$c+WfU  
try{ Z%3]  
Thread.sleep(nSecond); Ekx3GM_]  
} o]0v#2l'  
catch(Exception e)  _6a+" p  
{ l[=7<F  
e.printStackTrace (); YQ}xr^VA  
} t^0^He$Ot  
} e)dPv:oK3  
l4+!H\2  
//日志 +Hz});ix<  
public static void log(String sMsg) Mq-QWx"P  
{ 8d9&LPv  
System.err.println(sMsg); k=,,s(]tx  
} ,}15Cse  
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public static void log(int sMsg) 8$O=HE*  
{ 2j_YHv$I  
System.err.println(sMsg); ahi lp$v  
} 3w
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} ?bc-?<Xk  
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/* T9r
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**TestMethod.java -"qw5Y_oF?  
*/ 7;dTQ.%n  
package NetFox; y9d[-j ;w  
mA|&K8H  
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public class TestMethod { uP<w rlW  
5urM,1SQ@  
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public TestMethod() '< ]:su+  
{ ///xx/weblogic60b2_win.exe h8;B+#f`  
try{ V{17iRflf  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5b X*8H D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %M{qr!?uj  
SiteFileFetch fileFetch = new SiteFileFetch(bean); yX%T-/XJ  
fileFetch.start(); .<zW(PW  
} OE87&Cl"{t  
catch(Exception e){e.printStackTrace ();} y6.}h9~  
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} CZB!vh0  
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public static void main(String[] args) FQdz":5  
{ O9OD[VZk  
new TestMethod(); DSGtt/n  
} WAPN,WuW  
} :.kc1_veYS  
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