http断点续传简单实现（java)

/* =JySY@
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**SiteFileFetch.java :(S/$^U  
*/ @tjZvRtZ  
package NetFox; SCI-jf3WN  
import java.io.*; 56O<CgJF<  
import java.net.*; )z4kP09  
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public class SiteFileFetch extends Thread { @$b+~X)7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean nkCRe  
long[] nStartPos; //开始位置 ./BP+\)lO  
long[] nEndPos; //结束位置 *~t$k56  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (X`t"*y"  
long nFileLength; //文件长度 [pC-{~  
boolean bFirst = true; //是否第一次取文件 pYi=q
 
boolean bStop = false; //停止标志 }HA2ce\  
File tmpFile; //文件下载的临时信息 43orR !.Z  
DataOutputStream output; //输出到文件的输出流 t+4%,n f_1  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9q0,K" x)  
public SiteFileFetch(SiteInfoBean bean) throws IOException -SC2Zgi)A  
{ 1 [~|  
siteInfoBean = bean; x1hs19s  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); QF.wtMGF&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); CgTQGJ}-  
if(tmpFile.exists ()) )8N)Z~h  
{ \A~I>x  
bFirst = false; 6!}m$Dvt~  
read_nPos(); zm)CfEF 8  
} ^) b7m  
else WE Svkm;  
{ ]K0,nj*\c  
nStartPos = new long[bean.getNSplitter()]; -)->Jx:{  
nEndPos = new long[bean.getNSplitter()]; p
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} t&Y^W <  
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} $Bwvw)(%  
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public void run() /wCxf5q0  
{ jtVPv]  
//获得文件长度 Rp@}9qijb  
//分割文件 k f K"
i  
//实例FileSplitterFetch ZsK'</7  
//启动FileSplitterFetch线程 +[l{C+p  
//等待子线程返回 I}Gl*@K&O  
try{ )*L?PT  
if(bFirst) cX=b q_  
{ Dil4ut-$  
nFileLength = getFileSize(); HjF'~n  
if(nFileLength == -1) NYV0<z@M2M  
{ GL0':LsZ  
System.err.println("File Length is not known!"); { G>+.  
} },QFyT  
else if(nFileLength == -2) ])ZJ1QL1  
{ BKjPmrZ|  
System.err.println("File is not access!"); ewff(e9  
} 2Z1(J% 7  
else K v>#  
{ z )}wo3  
for(int i=0;i<nStartPos.length;i++) 8'_ ]gfF  
{ VTX'f2\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,vY I O  
} u #QSa$P  
for(int i=0;i<nEndPos.length-1;i++) [?r\b  
{ 1MzB?[gx  
nEndPos = nStartPos[i+1]; eEds-&_  
} WE8L?55_Au  
nEndPos[nEndPos.length-1] = nFileLength; Z(`K6`KM  
} Z_ *ZUN?B  
} w7ABnX  
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//启动子线程 h^,YYoA$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d5W[A#}  
for(int i=0;i<nStartPos.length;i++) oO9iB:w  
{ PL B=%[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ++RmaZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), sVl:EVv  
nStartPos,nEndPos,i); 5<ya;iK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C g,w6<7  
fileSplitterFetch.start(); %RF  
} BOcEL%+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _"e( ^yiK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vH:+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", KB-#):'  
nEndPos = " + nFileLength); HQ#L |LN  
// fileSplitterFetch[nPos.length-1].start(); ha'm`LiX  
tp3N5I  

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//等待子线程结束 a{YVz\?d}  
//int count = 0; I)4|?tb?  
//是否结束while循环 z&G3&?Z  
boolean breakWhile = false; v?'k)B  
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while(!bStop) (HgdmN%  
{ K1:)J.ca_  
write_nPos(); w9?wy#YI  
Utility.sleep(500); =|zyi|  
breakWhile = true; us *l+Jw,m  
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for(int i=0;i<nStartPos.length;i++) L7'X7WYf&  
{ 
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if(!fileSplitterFetch.bDownOver) \}&w/.T  
{ dufHd  
breakWhile = false; hzVr3;3Zn  
break; VTkT4C@I;Y  
} F>{uB!!L4  
} BP><G^  
if(breakWhile) y,eoTmaI  
break; {*  _ W  
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//count++; WED7]2>  
//if(count>4) Ho{?m^  
// siteStop(); lt2&uYgp  
} ^g"6p#S=n  
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System.err.println("文件下载结束！"); ag4^y&  
} 6m<9^NT  
catch(Exception e){e.printStackTrace ();} zT40,rk  
} \}
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//获得文件长度 l@9:VhU(  
public long getFileSize() _E-GHj>k z  
{ SQCuY<mD  
int nFileLength = -1; ::t!W7W  
try{ z@LP9+?dE  
URL url = new URL(siteInfoBean.getSSiteURL()); #.K&]OV/88  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); PltPIu)F  
httpConnection.setRequestProperty("User-Agent","NetFox"); uB9+E%jOdQ  
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int responseCode=httpConnection.getResponseCode(); a.Vs>1  
if(responseCode>=400) ITOGD  
{ ?7dDQI7^(  
processErrorCode(responseCode); RLr-xg$K-t  
return -2; //-2 represent access is error dz DssAHy  
} .j,&/y&  
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String sHeader; *Fs^T^ ?r  
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for(int i=1;;i++) h
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{ B9 {DO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }6(:OB?  
//Utility.log(in.readLine()); 1&WFs6  
sHeader=httpConnection.getHeaderFieldKey(i); A~t7I{`  
if(sHeader!=null) \%*y+I0>  
{ pEP.^[  
if(sHeader.equals("Content-Length")) }jXUd=.Nu  
{ @J)vuGS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &0blHDMj{#  
break; (6aZQ`H  
} uSbg*OA  
}  HuClO  
else Y`RfE  
break; F:U_gW?  
} Gj0NN:  
} cZ,_O~  
catch(IOException e){e.printStackTrace ();} z[Qv}pv  
catch(Exception e){e.printStackTrace ();} r#}%sof  
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Utility.log(nFileLength); smNr%}_g  
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return nFileLength; my0->W%L  
} Tj#XsD?J  
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//保存下载信息（文件指针位置） 60$   
private void write_nPos() y%AJ>@/;  
{ >TJ$Z3
 
try{ vUNE!j  
output = new DataOutputStream(new FileOutputStream(tmpFile)); pu#<qD*w  
output.writeInt(nStartPos.length); %;gWl1&5  
for(int i=0;i<nStartPos.length;i++) Lr&tpB<  
{ ]y$C6iUY*  
// output.writeLong(nPos); 1jb@nxRjO  
output.writeLong(fileSplitterFetch.nStartPos); f#+ h_1#  
output.writeLong(fileSplitterFetch.nEndPos); w[_Uv4M  
} _69\#YvCG  
output.close(); ' ga2C\)  
} 5sUnEHN  
catch(IOException e){e.printStackTrace ();} YG|T;/-  
catch(Exception e){e.printStackTrace ();} }Z=Qy;zk  
} pq`MO .R  
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.:/@<V+K  
//读取保存的下载信息（文件指针位置） `z.#O\@o  
private void read_nPos() ]QQ"7_+
  
{ <k1gc
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try{ 4 n(
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); W525:h52{  
int nCount = input.readInt(); T@Xi
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nStartPos = new long[nCount]; D%btlw?{  
nEndPos = new long[nCount]; o%iTYR:x  
for(int i=0;i<nStartPos.length;i++) !{LwX
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{ PGDlSB^O  
nStartPos = input.readLong(); R&A.F+Zgt  
nEndPos = input.readLong(); b/`'?| C  
} 3@JwL{C  
input.close(); 3WHH3co[  
} w4mL/j  
catch(IOException e){e.printStackTrace ();} 04TV./uA  
catch(Exception e){e.printStackTrace ();} 9|,AhyhO  
} C09@2M'  
5=\b+<pE  
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private void processErrorCode(int nErrorCode) NgKNT}JDv  
{ o=}?aC3I  
System.err.println("Error Code : " + nErrorCode); i\b2P2 `B  
} :csLZqn[  
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:
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//停止文件下载 k,J?L-F  
public void siteStop() 4{&  
{ UWp(3FQ  
bStop = true; K[H$qJmPX  
for(int i=0;i<nStartPos.length;i++) MtljI6  
fileSplitterFetch.splitterStop(); o/#e y  
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} d!cx%[  
} 5{UGSz 1  
//负责部分文件的抓取 GzX@Av$  
**FileSplitterFetch.java ]2+(i  
*/ O #"O.GX<  
package NetFox; $oz ZFvJF  
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\}5\^&}_  
import java.io.*; &%<G2x$  
import java.net.*; ZZUCwczI  
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public class FileSplitterFetch extends Thread { fsu'W]f  
]v#Q\Q8>  
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String sURL; //File URL .+.Pc_fv  
long nStartPos; //File Snippet Start Position Im2g2]  
long nEndPos; //File Snippet End Position i*3'O:Gq  
int nThreadID; //Thread's ID w$_ooQ(_;Q  
boolean bDownOver = false; //Downing is over rBaK$Ut  
boolean bStop = false; //Stop identical 6k-]2,\#  
FileAccessI fileAccessI = null; //File Access interface n:{yri+  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException | =&r) ~  
{ pdM|dGq^  
this.sURL = sURL; |"arVde  
this.nStartPos = nStart; zPn8>J<.0Q  
this.nEndPos = nEnd; zT@vji%Y  
nThreadID = id; mYZH]oo  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 U<t Qj`  
} 0>vm&W<?)  
iVA_a8}  
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public void run() "qF8'58  
{ GCrMrZ6  
while(nStartPos < nEndPos && !bStop) ,+XQ!y%  
{ vjWS35i  
1'h?qv^(  
`eA0Z:`g!  
try{ ) E5ax~  
URL url = new URL(sURL); &}WSfZ0{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gxF3gM  
httpConnection.setRequestProperty("User-Agent","NetFox"); vg<_U&N=-r  
String sProperty = "bytes="+nStartPos+"-"; qzq>C"z\Y$  
httpConnection.setRequestProperty("RANGE",sProperty); u >x2  
Utility.log(sProperty); >%{h_5  
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InputStream input = httpConnection.getInputStream(); :t(}h!7  
//logResponseHead(httpConnection); 'O CVUF,  
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byte[] b = new byte[1024]; *fl1 =Rfr  
int nRead; >[[< 5$,T  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {Tx+m;5F  
{ ,^/;!ErR$  
nStartPos += fileAccessI.write(b,0,nRead); l-5-Tf&j  
//if(nThreadID == 1) |(Sqd;#v  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^#;2 Pd>  
} | r2'B  
O*CKyW_$t  
qk
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Utility.log("Thread " + nThreadID + " is over!"); `":< ]lj  
bDownOver = true; 'kp:yI7w  
//nPos = fileAccessI.write (b,0,nRead); |>m@]s7Z  
} V /|@  
catch(Exception e){e.printStackTrace ();} ]F,5Oh :OY  
} CpA=DnZ  
} ~s+\Y/@A  
).LJY<A  
h.PY$W<  
//打印回应的头信息 dP )YPy_`  
public void logResponseHead(HttpURLConnection con) [mX\Q`)QP  
{ 07n=H~yU  
for(int i=1;;i++) W Qe>1   
{ ]ko>vQ4]3  
String header=con.getHeaderFieldKey(i); `CW=*uBH  
if(header!=null)  </7J:#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (xM
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Utility.log(header+" : "+con.getHeaderField(header)); od!TwGX  
else ! @|"84  
break; K@+&5\y]  
} (Ys0|I3  
} ^,,|ED\M{m  
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public void splitterStop() `g3H;E  
{ hX8;G!/  
bStop = true; .^uNzN~  
} R9k Z#  
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?  
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} _K'YaZTa;~  
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/* g+U6E6}1  
**FileAccess.java UkeX">  
*//文件访问(定位，写) A+>+XA'  
package NetFox; pL
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import java.io.*; FK>8(M/  
pf[bOjtR  
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public class FileAccessI implements Serializable{ j&u{a[Y/}  
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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 cJGU~\  
RandomAccessFile oSavedFile; 4;y*y tY*  
long nPos; J&2cf#  
p v%`aQ]o{  
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public FileAccessI() throws IOException <t\!g  
{ K '7M\:zy  
this("",0); 5V8WSnO  
} >E6w,Ab  
vT)FLhH6*  
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public FileAccessI(String sName,long nPos) throws IOException 0.qnbDw_  
{ ZDMS:w.'T  
oSavedFile = new RandomAccessFile(sName,"rw"); AfB,`l`k  
this.nPos = nPos; s&TPG0W  
oSavedFile.seek(nPos); AKu]c-  
} *7FtEk/l  
Gu-6~^
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h:[%' htz  
public synchronized int write(byte[] b,int nStart,int nLen) Bz!SZpW(M  
{ 7\HjQ7__  
int n = -1; :;HJ3V;  
try{ t,Ss3  
oSavedFile.write(b,nStart,nLen); `B-jwVrN(  
n = nLen; nF`_3U8e  
} =~15q=XY0  
catch(IOException e) '9.L5*wh]  
{ !W^P|:Qt  
e.printStackTrace (); ~x4]^XS  
} M8(N9)N  
[`2V!rU  
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return n; Y,n&g45m  
} E
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#?u#=]  
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} Xw)W6H|  
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/* Vq4g#PcG  
**SiteInfoBean.java G L
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*/ ';'gKX
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package NetFox; }6b" JoC  
j2^Vz{  
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public class SiteInfoBean { b v5BV  
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@?e+;Sx  
private String sSiteURL; //Site's URL k}18 ~cWM  
private String sFilePath; //Saved File's Path
ld  
private String sFileName; //Saved File's Name =e*S h0dK  
private int nSplitter; //Count of Splited Downloading File hX4V}kj  
E7mB=bt>=  
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public SiteInfoBean() a!guZUg6  
{//nSplitter的缺省值为5 jJbS{1z  
//default value of nSplitter is 5 D6N32q@  
this("","","",5); AO[/-Uij  
} =/kwUjC?  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %^pm~ck!  
{  |pgrR7G'  
sSiteURL= sURL; cfSQqH  
sFilePath = sPath; Yc^;?n`x  
sFileName = sName; 6
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this.nSplitter = nSpiltter; Xnc?o
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c'md)nD2M  
} H'a6] ]2  
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public String getSSiteURL() 40=*Ul U-  
{ *{x8@|K8  
return sSiteURL; 7/e25LS!`U  
} $&Lw 2 c0  
<]Btx;}  
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public void setSSiteURL(String value) Fzmc#?  
{ '/2)I8  
sSiteURL = value; z#HNJAQ#|  
} b]5/IT)@O  
mlLx!5
h=  
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public String getSFilePath() {&TP&_|H  
{ 9s4>hw@u  
return sFilePath; C[R|@9NI  
} *)bh6b=7  
0g'MFS  
6qR5A+|;  
public void setSFilePath(String value) I+eKuWB  
{ pN=>q<]L  
sFilePath = value; <IBWA0A=8a  
} VPvQ]}g6k  
4OOI$J$Jh  
ech1{v\B|  
public String getSFileName() NjFlV(XT}  
{ ]kdU]}z  
return sFileName; +OaBA>Jh9  
} gY {/)"
 
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}Jo}K)>!  
public void setSFileName(String value) fA)4'7UT  
{ sjy/[.4-  
sFileName = value; @HQqHO&N  
} Esdv+f}4;  
_a\$uVZ   
* `3+x  
public int getNSplitter() Owz>g4l r  
{ |
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return nSplitter; T_j0*A$  
} B-p ].  
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0ky3rFSh1  
public void setNSplitter(int nCount) }hA)p:  
{ Lvb'qZ6n  
nSplitter = nCount; V~7Oa2'#B  
} Ow0(q^H<  
} U!b~
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/* eI
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**Utility.java wvI}|c  
*/ (V>/[Ev  
package NetFox; x-T7 tr&(  
nNhb,J  
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public class Utility { a;f A0_  
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public Utility() 9w<k1j  
{ ~pw%p77)  
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} ua!RwSo  
eB_ M *+^  
//线程睡眠 `svOPB4C'  
public static void sleep(int nSecond) V^kl_!@  
{ w|U7pUz  
try{ IAd[_<9D  
Thread.sleep(nSecond); _SrkR7  
} Nazr4QU  
catch(Exception e) ]t-B-(D  
{ DI\^&F)3T2  
e.printStackTrace (); & &:ZY4`  
} 7&2CLh  
} @<$_X1)s  
6'|NALW  
//日志 iza.' Mm~  
public static void log(String sMsg) FTh/1"a  
{ YR.f`-<Z  
System.err.println(sMsg); Mb+CtI_'  
} uDMyO<\  
SJO^.[  
2 W Wr./q  
public static void log(int sMsg)  )QB9zl:  
{ -^,wQW:o)  
System.err.println(sMsg); 2+C8w%F8  
} y^:6D(SR  
} <-xu
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L8cPNgZ   
/* +IM6 GeH  
**TestMethod.java 6AKT-r.  
*/ iI@(Bl
]  
package NetFox; TnLblkX  
0E`6g6xMS  
GD<pqm`vVY  
public class TestMethod { e ls&_BPE  
yHxi^D]  
@l?2",  
public TestMethod() g?9%_&/})A  
{ ///xx/weblogic60b2_win.exe pJ_>^i=  
try{ ]Czq A c  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); vb2aj!8_?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Y#f
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SiteFileFetch fileFetch = new SiteFileFetch(bean); wi S8S{K5  
fileFetch.start(); [KsVI.gn  
} J:2Su1"ODh  
catch(Exception e){e.printStackTrace ();} ]*\<k  
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} o[>p  
"yPKdwP  
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public static void main(String[] args) l]mn4cn3  
{ Cz#3W8jV  
new TestMethod(); M5l*D'GE]  
} &;@U54,wV  
} \\,z[C  
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