http断点续传简单实现（java)

/* giddM2'  
**SiteFileFetch.java rPW9lG  
*/ a5g1.6hF  
package NetFox; '_=XfTF  
import java.io.*; =)6|lz^  
import java.net.*; vs.}Bou]  
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public class SiteFileFetch extends Thread { H&ZsMML/%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean $J:~jY/J  
long[] nStartPos; //开始位置 0jefV*3qpB  
long[] nEndPos; //结束位置 ws}>swR,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 KI<Vvcm  
long nFileLength; //文件长度 dG]s_lb9H  
boolean bFirst = true; //是否第一次取文件 p@xK`=Urb  
boolean bStop = false; //停止标志 +@oo8io  
File tmpFile; //文件下载的临时信息 pK2n'4 C  
DataOutputStream output; //输出到文件的输出流 VrRBwvp-K  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {I_I$x_  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?#;zB  
{ .We"j_ }  
siteInfoBean = bean; p>]2o\["  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }NJ? .Y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); B,dKpz;kFg  
if(tmpFile.exists ()) s%qK<U4@;Q  
{ m&#a M8:\  
bFirst = false; Mio~CJ"?  
read_nPos(); M}6? |ir  
} C,m o4,Q  
else bQM_rqjJGw  
{ Aa/lKiiz  
nStartPos = new long[bean.getNSplitter()]; ((%g\&D  
nEndPos = new long[bean.getNSplitter()]; U~8 oE_+  
} _-I0f##.  
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} M e  
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public void run() VXAgp6  
{ f&ym'S  
//获得文件长度 9f4#b8  
//分割文件 e$^O_e  
//实例FileSplitterFetch ou@ P#:<B  
//启动FileSplitterFetch线程 :bgi*pR{  
//等待子线程返回 q|%(47}z  
try{ s],+]<qX  
if(bFirst) ATU 2\Y  
{ 8W"~>7/>D  
nFileLength = getFileSize(); xCV3HnZ  
if(nFileLength == -1) c.PPVqx  
{ z<jWy$Ta;  
System.err.println("File Length is not known!"); q<b;xx  
} r,x;q  
else if(nFileLength == -2) eID"&SSU  
{ toEmIa~o6  
System.err.println("File is not access!"); Hdh'!|w  
} s!2pOH!u
 
else V4!RUqK  
{ !R WX1Z  
for(int i=0;i<nStartPos.length;i++) -_ [Z5%B  
{ e}e\*BL  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P~:W+!@5v  
} 16YJQ ue  
for(int i=0;i<nEndPos.length-1;i++) QP?Z+P<  
{ Nze#u;  
nEndPos = nStartPos[i+1]; 7@m
  
} U&/Jh^Yy  
nEndPos[nEndPos.length-1] = nFileLength; lV^sVN Z]  
} c;ELAns>  
} Kl$!_$  
n}yqpW!%n  
eGblQGRS  
//启动子线程 #uT-_L}sw  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^m{kn8  
for(int i=0;i<nStartPos.length;i++) '@Y@H
,  
{ %u43Pj  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JF_\A)<ki  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), BjJ$I^  
nStartPos,nEndPos,i); ])a?ri  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5Y)!q?#H  
fileSplitterFetch.start(); ^;$f-e  
} BRV /7ao="  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .)B_~tct  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~-6Kl3Y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >0i?}  
nEndPos = " + nFileLength); ^owEB%  
// fileSplitterFetch[nPos.length-1].start(); 9+SeG\Th  
%"DEgIP  
BJk\p.BVN  
//等待子线程结束 {`~{%2ayq7  
//int count = 0; Om{[ <tL  
//是否结束while循环 ![:S~x1  
boolean breakWhile = false; E'&UWDh  
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while(!bStop) M:nXn7)+  
{ ((Ec:(:c  
write_nPos(); .7Ys@;>B  
Utility.sleep(500); co<){5zOT  
breakWhile = true; l@<^V N@  

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for(int i=0;i<nStartPos.length;i++) 5}~*,_J2Z  
{ C_PXh>H]'  
if(!fileSplitterFetch.bDownOver) <h U ZD;  
{ d^Ra1@0"q2  
breakWhile = false; <{YP=WYW  
break; 23y7l=.b/  
} DhY9)>4M  
} )Bl% {C  
if(breakWhile) HQaKG4Z  
break; \h :Rw|  
IL}pVa00{n  
c$?qN&X_K  
//count++; g;\zD_":l  
//if(count>4) . %tc7`k8  
// siteStop(); \"_;rJ{!aE  
} o]MQ)\r  
s:R>uGYOd  
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System.err.println("文件下载结束！"); @+Berb  
} *AGC[w}/  
catch(Exception e){e.printStackTrace ();} A,lcR:@w  
} mv SNKS  
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//获得文件长度 Rr4r[g#  
public long getFileSize() .+ai dWd  
{ 1
5uVvp/  
int nFileLength = -1; zBB4lC{q  
try{ -C
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URL url = new URL(siteInfoBean.getSSiteURL()); {TzKHnP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i<bFF03*S  
httpConnection.setRequestProperty("User-Agent","NetFox"); A7+eWg{  
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5^GUuFt5m  
int responseCode=httpConnection.getResponseCode(); ^%#v AS  
if(responseCode>=400) :8E(pq|1PB  
{ isDBNXV:  
processErrorCode(responseCode); HHWB_QaL  
return -2; //-2 represent access is error h 
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} 4eBM/i  
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String sHeader; O#Xq0o  
+To{Tm-  
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for(int i=1;;i++) +S^Uw'L$=T  
{
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2Ev~[Hb.  
//Utility.log(in.readLine()); rbO9NRg>  
sHeader=httpConnection.getHeaderFieldKey(i); _s|C0Pt  
if(sHeader!=null) WkXa%OZ  
{ Sw%=/g  
if(sHeader.equals("Content-Length")) p!|Wp  
{ rm+|xvZ4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Et
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break; P9G c)$6{p  
} x}AWWmXv  
} g>/,},jv[x  
else UXDd
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break; eMPi ho  
} Q;)[~p  
} ~U~
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catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} ,Tvk&<!0  
=>)l6**UE  
80![aj}z4G  
Utility.log(nFileLength); ~>k<I:BtrT  
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return nFileLength; $FNj>1  
} ht!o_0{~  
5^ARC^v  
+Z/*=;  
//保存下载信息（文件指针位置） P"XF|*^U  
private void write_nPos() -3_-n*k!  
{ Q
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try{ \WQ\q \  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =n cu#T]  
output.writeInt(nStartPos.length); #i%it  
for(int i=0;i<nStartPos.length;i++) #:3ca] k  
{ r0+lH:G*q  
// output.writeLong(nPos); jdK~]eld=  
output.writeLong(fileSplitterFetch.nStartPos); P5P:_hr  
output.writeLong(fileSplitterFetch.nEndPos); #OqQD6  
} AT<K>&)  
output.close(); +j1s*}8  
} "|{NRIE  
catch(IOException e){e.printStackTrace ();} &-:ZM0Fl  
catch(Exception e){e.printStackTrace ();} M56^p,  
} P%8 Gaa=  
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//读取保存的下载信息（文件指针位置） ZNuz%VO  
private void read_nPos() 3=RVJb  
{ Q})x4  
try{ 6NPCp/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O:IU|INq8  
int nCount = input.readInt(); ` .|JTm[  
nStartPos = new long[nCount]; f=+|e"i#p  
nEndPos = new long[nCount]; umaF}}-Q{  
for(int i=0;i<nStartPos.length;i++) 4/;hA z  
{ 8UJK]_99I,  
nStartPos = input.readLong(); ]P;uQ!  
nEndPos = input.readLong(); %PRG;kR  
} 9t:F![rg  
input.close(); B7zyMh  
} = NHuj.  
catch(IOException e){e.printStackTrace ();} ##+|zka!U  
catch(Exception e){e.printStackTrace ();} }TY}sr  
} G0oY`WXOB  
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private void processErrorCode(int nErrorCode) $M{MOehZ  
{ /j/,@,lw7z  
System.err.println("Error Code : " + nErrorCode); *oopdGue  
} 0zQ"5e?qy  
6_]-&&Nr  
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//停止文件下载 3#N'nhUzA  
public void siteStop() t5t,(^;f  
{ RfH.WXi  
bStop = true; C))5,aX  
for(int i=0;i<nStartPos.length;i++) ~A@T_*0  
fileSplitterFetch.splitterStop(); i[_(0P+Da  
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} Z6s-n$dSm  
} '!eg9}<  
//负责部分文件的抓取 )4:K@  
**FileSplitterFetch.java =1Nz*
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*/ 1(%9)).K  
package NetFox; EQe!&;   
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import java.io.*; YnM&t ;TX  
import java.net.*; .#^ta9^t7  
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public class FileSplitterFetch extends Thread { mj{B_3b5  
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String sURL; //File URL -R%T Dx  
long nStartPos; //File Snippet Start Position d}D%%noIu  
long nEndPos; //File Snippet End Position o\/&05rp]  
int nThreadID; //Thread's ID #(@!:f1  
boolean bDownOver = false; //Downing is over *JnY0xP  
boolean bStop = false; //Stop identical ~6{iQZa1Y  
FileAccessI fileAccessI = null; //File Access interface 8;PS>9<  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HQp\0NC]  
{ q+iG:B/Z  
this.sURL = sURL; pbCj ^  
this.nStartPos = nStart; B":9C'tip  
this.nEndPos = nEnd; 87!D@X
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nThreadID = id; /esdtH$=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 TWzlF>4N  
} cI Sugk~  
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public void run() 6a*?m{  
{ dU}Cb?]7s  
while(nStartPos < nEndPos && !bStop) D\:dn  
{ ]I,(^Xq3a(  
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try{ Z8Iqgz7|y  
URL url = new URL(sURL); +3yG8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e{EC#%x_  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7vo8lnQ{  
String sProperty = "bytes="+nStartPos+"-"; -F. c<@*E  
httpConnection.setRequestProperty("RANGE",sProperty); >jU25"XI[  
Utility.log(sProperty); zif&;)wV/  
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InputStream input = httpConnection.getInputStream(); /!#A'#Z  
//logResponseHead(httpConnection); _<E.?K$gbU  
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byte[] b = new byte[1024]; )[S#:PP  
int nRead; j.&Y'C7GOC  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) oE.Ckz~*d  
{ {q/;G!ON.S  
nStartPos += fileAccessI.write(b,0,nRead); 216`rQ}z  
//if(nThreadID == 1) +v2)'?BS  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vbD""  
} {Gr"lOi*@  
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Utility.log("Thread " + nThreadID + " is over!"); zv7)JH7EV&  
bDownOver = true; lak,lDt]  
//nPos = fileAccessI.write (b,0,nRead); b'ZzDYN  
} {2%'=v  
catch(Exception e){e.printStackTrace ();} F pT$D  
} f\rE{%  
} d,b]#fj  
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//打印回应的头信息 :GN++\1pw  
public void logResponseHead(HttpURLConnection con) e-Oz`qW~  
{ eslv
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for(int i=1;;i++) gyQPQ;"H$2  
{ <PFF\NE9  
String header=con.getHeaderFieldKey(i); Q#X'.](1  
if(header!=null) l^XOW- ;u  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); S n<X  
Utility.log(header+" : "+con.getHeaderField(header)); ;PB_@Zg  
else +I\54PBws  
break; x=Aq5*A0  
} S&'?L0  
} 
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VP~(;H5%  
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public void splitterStop() -dWg1`;  
{ ^D
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bStop = true; l1#.rg  
} fLpWTkr0  
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8f<y~L_(`  
} k+%&dEE|vH  
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/* fJP *RVz  
**FileAccess.java +0 }_
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*//文件访问(定位，写) C(9"59>{]y  
package NetFox; c3Gy1#f:#2  
import java.io.*; (/0dtJ  
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public class FileAccessI implements Serializable{ ?E_;[(Mcr  
/\_n5XI1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 i6A9|G$H
 
RandomAccessFile oSavedFile; 6" <(M@
 
long nPos; yf;TIh%)=  
<[D>[  
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public FileAccessI() throws IOException D)pTE?@W'  
{ j>e RV ol  
this("",0); 0{uaSR  
} 3u/AqL  
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public FileAccessI(String sName,long nPos) throws IOException rQ_]%ies8  
{ n((A:b  
oSavedFile = new RandomAccessFile(sName,"rw"); a|=^   
this.nPos = nPos; w3"L5;oH  
oSavedFile.seek(nPos); lz::6}  
} ?pfr^ !@$  
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public synchronized int write(byte[] b,int nStart,int nLen) dCS f$5  
{ qrp@   
int n = -1; +}M3O]?4  
try{ 7)Vbp--b#  
oSavedFile.write(b,nStart,nLen); lZ7 $DGe  
n = nLen; <xF]ca  
} T)OR HJ&,  
catch(IOException e) Vs{\ YfF  
{ x~R,rb   
e.printStackTrace (); uDXV@;6<  
} |,5|ZpgL  
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return n; D*[Jrq,  
} F[$cE  
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} NU?<bIQ  
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/* c`p'5qz  
**SiteInfoBean.java Jy%?"wn  
*/ LtX53c  
package NetFox; Y1I)w^}:  
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+x}9a~QG#  
public class SiteInfoBean { ;>jEeIlT  
b^C27s  
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private String sSiteURL; //Site's URL <7F-WR/2n  
private String sFilePath; //Saved File's Path T:Nk9t$W7@  
private String sFileName; //Saved File's Name u "jV#,,  
private int nSplitter; //Count of Splited Downloading File +Tu?PuT7k  
r>F
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public SiteInfoBean() ls:oC},p*  
{//nSplitter的缺省值为5 ]q{_i  
//default value of nSplitter is 5 NT.#U?9c  
this("","","",5); kt)Et  
}
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2<I=xWwFA  
{ z5]6"v-  
sSiteURL= sURL; c_*w<vJ-'  
sFilePath = sPath;
/
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sFileName = sName; _8u TK
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this.nSplitter = nSpiltter; <JWU@A-.
y  
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$$NWN?H~  
} -i2rcH  
 )^{}ov  
8R3{
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public String getSSiteURL() Fb]+h)on  
{ +`k30-<P  
return sSiteURL; N~8H\  
} MVzuE}  
+:;ddV  
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public void setSSiteURL(String value) vnvpb! @Q  
{ dE_Xd:>  
sSiteURL = value; mYgfGPF`  
} {V QGfN  
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public String getSFilePath() Cj8&wz}ez  
{ js81@WX!c  
return sFilePath; .<`)`:n+B  
} xjo`u:BH  
.u&xo{$'dS  
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public void setSFilePath(String value) /#Aw7F$Ey  
{ ZDFq=)0C  
sFilePath = value;  *XhlIQ  
} r/!,((Z\  
[_)`G*X(N  
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public String getSFileName() CwX?%$S   
{ F0U %m   
return sFileName; ]H n:c'aT  
} hc|A:v)]  
t`K9K"|k  
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public void setSFileName(String value) ZTzec zXpQ  
{ EE 1D>I  
sFileName = value; <J;O$S  
} jV sH  
]XEyG7D  
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public int getNSplitter() 6LDZ|K@  
{ CqnHh@]nu  
return nSplitter; Pw<?Dw]m  
} 71nZi`AR  
5qnei\~  
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public void setNSplitter(int nCount) oWY3dc  
{ 7#E/Q~]'6  
nSplitter = nCount; 9A.NM+u7  
} DS(>R!bb  
} aH6j,R%  
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*U
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/* `VwG]2 I  
**Utility.java fYP,V0P  
*/ NRx 7S9W  
package NetFox; @o0HD
S  
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public class Utility { oYw?kxRZ  
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public Utility() $JOz7j(  
{ LOkgeJuWv  
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} Ms6;iW9  
3J"`mQ  
//线程睡眠 6Mc&=}bV  
public static void sleep(int nSecond) KcV"<9rE  
{ lD$s, hp  
try{ la{?
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Thread.sleep(nSecond); VDnrm*  
} }` 3-  
catch(Exception e) DL,R~  
{ X]}ai5  
e.printStackTrace (); )$^xbC#j`3  
} 28^/By:J  
} LBG`DYR@  
n/;{-  
//日志 h's[) t  
public static void log(String sMsg) ]B(}^N>WH  
{ .K~V DUu  
System.err.println(sMsg); i}LQ}35@  
} \)28,`  
^r}Uu~A>  
GThGV"  
public static void log(int sMsg) i-0 :Fs  
{ 8i"CU:(  
System.err.println(sMsg); ]Qe~|9I  
} a)2l9  
} 1W*Qc_5 v1  
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O8hx}dOjA  
/* XzV>q~I3|E  
**TestMethod.java !"phz&E5ah  
*/ CxaI@+  
package NetFox; jR1^e$  
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("A45\5  
public class TestMethod { wa[J\lW  
dh]Hf,OLF  
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public TestMethod() 3 a(SmM:  
{ ///xx/weblogic60b2_win.exe q:up8-LAr  
try{ o$bQ-_B`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); mKM[[l&A  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2O(k@M5E?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); br0\O  
fileFetch.start(); f(}&8~&  
} d+P<ce2G  
catch(Exception e){e.printStackTrace ();} .))k
  
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M&zB&Ia"'  
} hDJ+Rk@  
.nr%c*JUp  
U#Kw+slM  
public static void main(String[] args) +:#g6(P]  
{ h Q Att  
new TestMethod(); zGO_S\  
} MAqETjB  
} \py&v5J)s!  
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