http断点续传简单实现（java)

/* to
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**SiteFileFetch.java c_T+T
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*/ EXsVZg"#  
package NetFox; A,EuUp  
import java.io.*; >d(:XP6J  
import java.net.*; d&lT/S  
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public class SiteFileFetch extends Thread { z.|[g$F  
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SiteInfoBean siteInfoBean = null; //文件信息Bean " {X0&  
long[] nStartPos; //开始位置 nlZJ
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long[] nEndPos; //结束位置 JS/~6'uB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Pk;1q?tGw  
long nFileLength; //文件长度 7x]q>Y8T  
boolean bFirst = true; //是否第一次取文件 D&x
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boolean bStop = false; //停止标志 G8WPXj(  
File tmpFile; //文件下载的临时信息 b7y#uL1AE  
DataOutputStream output; //输出到文件的输出流 TR%8O;  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >2v<;.  
public SiteFileFetch(SiteInfoBean bean) throws IOException {Iz"]Wh<f  
{ FOhq&\nkU  
siteInfoBean = bean; T*g}^TEh  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Z_a@,k:+[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); cOo@UU P  
if(tmpFile.exists ()) _rjB.  
{ d gRTV<vM  
bFirst = false; P[<EFjE  
read_nPos(); >nOzz0,  
} M&~cU{9c  
else Egr'IbB  
{ wS}Rl}#Oh?  
nStartPos = new long[bean.getNSplitter()]; kQQhZ8Ch  
nEndPos = new long[bean.getNSplitter()]; &=`6- J  
} i$W E1-  
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} /o]j  
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public void run() AB")aX2%E  
{ 
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//获得文件长度 =V*4&OU  
//分割文件 R'1L%srTM+  
//实例FileSplitterFetch 5KvqZ1L  
//启动FileSplitterFetch线程 2z615?2_U  
//等待子线程返回 #uillSV  
try{ DY6ra% T  
if(bFirst) (D <o=Q  
{ fS?fNtD6<  
nFileLength = getFileSize(); Od@<L  
if(nFileLength == -1) vB;$AFh{  
{ EaXDY<  
System.err.println("File Length is not known!"); ug.'OR  
} os~}5QJ  
else if(nFileLength == -2) KM jnY2  
{ )'Yoii{dSU  
System.err.println("File is not access!"); IWD21lS  
} Fl;!'1  
else FST}:*dOe5  
{ nH -1,#`g  
for(int i=0;i<nStartPos.length;i++) oq3{q  
{ Ad]oM]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); k}r)I.Lp  
} 9HJA:k*k|  
for(int i=0;i<nEndPos.length-1;i++) 8w]>SEGFs  
{ g{%2*{;i  
nEndPos = nStartPos[i+1]; _rjLCvv-  
} r]'Q5l4j6"  
nEndPos[nEndPos.length-1] = nFileLength; I!uGI  
} 1?5UVv_F  
}
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//启动子线程 08JVX'X-mr  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .vJt&@NO  
for(int i=0;i<nStartPos.length;i++) _z(ydL*  
{ UZ}>
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UOtrq=y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {%Ujp9i  
nStartPos,nEndPos,i); I'%(f@u~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D"RxI)"HP  
fileSplitterFetch.start(); ~A =?_5kJ  
} SP |R4*KY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wM#BQe3t#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); sM8AORd  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", vhaUV#V"  
nEndPos = " + nFileLength); zgR@-OtFZ  
// fileSplitterFetch[nPos.length-1].start(); }2-p=Y:6  
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//等待子线程结束 >W[#-jA_Z  
//int count = 0; sB>ZN3ptH^  
//是否结束while循环 YMEI J}  
boolean breakWhile = false; ?g~g GQV  
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while(!bStop) B$M4f7  
{ 3Cgv($xl&  
write_nPos(); "5204I  
Utility.sleep(500); -tIye{  
breakWhile = true; {)(Mkm+d  
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for(int i=0;i<nStartPos.length;i++) 6 2#@Y-5  
{ L*OG2liJ  
if(!fileSplitterFetch.bDownOver) bFhZSk)  
{ "U!Vdt2vp  
breakWhile = false; =~
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break; #(QS5J&Qq  
} +Sc2'z>R  
} NL,6<ZOon,  
if(breakWhile) ++n_$Qug  
break; xR8y"CpE  
~ mzX1[  
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//count++; #jJ0
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//if(count>4) ZUD{V  
// siteStop(); P?^%i  
} *j(UAVp  
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System.err.println("文件下载结束！"); !jf!\Uu[U  
} ep4?;Qmho  
catch(Exception e){e.printStackTrace ();} W[R`],x`  
} WcQkeh3n  
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# [ +n(  
//获得文件长度 #&ei  
public long getFileSize() +IMt$}7[  
{ +:W/=C d(h  
int nFileLength = -1; ht#,v5oG>f  
try{ EeHghq  
URL url = new URL(siteInfoBean.getSSiteURL()); @Ko#nDEq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -/ G#ls|?  
httpConnection.setRequestProperty("User-Agent","NetFox"); `n@;%*6/  
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int responseCode=httpConnection.getResponseCode(); 3-oKY*jO  
if(responseCode>=400) [)?9|yY"`  
{ J:J/AgJuH  
processErrorCode(responseCode); fda4M  
return -2; //-2 represent access is error ii&ckg>]z  
} 4]FS jVO  
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String sHeader; ]TJ258P}  
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for(int i=1;;i++) u1gD*4+  
{ Nf)SR#;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =dwy 4  
//Utility.log(in.readLine()); "&{.g1i9  
sHeader=httpConnection.getHeaderFieldKey(i); 6J_
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if(sHeader!=null) ZuZCIqN  
{ D^a(|L3;  
if(sHeader.equals("Content-Length")) :wEy""*N0  
{ q&}+O  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); i9V,  
break; c$lZ\r"  
} mN>(n+ly  
} .s?^y+e_  
else :sw@1  
break; z`eMb  
} :Gzp (@<@e  
} f]mVM(XZN  
catch(IOException e){e.printStackTrace ();} R\Ckk;<$  
catch(Exception e){e.printStackTrace ();} OI8}v  
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Utility.log(nFileLength); E^A!k=>  
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return nFileLength; q: X^V$`  
} 3[m2F O,Z  
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//保存下载信息（文件指针位置） ;Wa&Dg/5`  
private void write_nPos() Jl6lZd(Np  
{ dt>9mF q  
try{ \.+:yV<$  
output = new DataOutputStream(new FileOutputStream(tmpFile));
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output.writeInt(nStartPos.length); OOXP1L  
for(int i=0;i<nStartPos.length;i++) -%Ce  
{ =diGuIB  
// output.writeLong(nPos); gX$gUB) x  
output.writeLong(fileSplitterFetch.nStartPos); ~3&hvm[IQ  
output.writeLong(fileSplitterFetch.nEndPos); dPxJ`8  
} W`P>vK@=  
output.close(); O4:_c-V2  
} sl(go^  
catch(IOException e){e.printStackTrace ();} ~w9`l8/0  
catch(Exception e){e.printStackTrace ();} lgD%  
} UI'fzlB  
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//读取保存的下载信息（文件指针位置） kBnb9'.A1  
private void read_nPos() Rlm28  
{ HuKOb4g  
try{ g$vOWSI+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |/$954Hr#<  
int nCount = input.readInt(); (uy\~Zb  
nStartPos = new long[nCount]; &Nw|(z&$  
nEndPos = new long[nCount]; bE@Eiac  
for(int i=0;i<nStartPos.length;i++) .TDg`O24c,  
{ Sqyju3Yp  
nStartPos = input.readLong(); Eau V
  
nEndPos = input.readLong(); +?[s"(  
} )>^Ge9d]  
input.close(); ]"htOO  
} \rg;xZa5  
catch(IOException e){e.printStackTrace ();} ?<5KLvGv  
catch(Exception e){e.printStackTrace ();} QAMcI:5  
} 1_]%,  
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private void processErrorCode(int nErrorCode) Sfp-ns32%A  
{ ?Iij[CbU  
System.err.println("Error Code : " + nErrorCode); XW\ 3ttx  
} 4Ssy (gt  
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//停止文件下载 ue4{h  
public void siteStop() #?e
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{ dWe
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bStop = true; g!r)yzK  
for(int i=0;i<nStartPos.length;i++) J83C]2~7  
fileSplitterFetch.splitterStop(); rW_cLdh]#  
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} yu>;m.e_  
} J!dv"Ww"  
//负责部分文件的抓取 rusYNb1J  
**FileSplitterFetch.java -w8?Ur1x:  
*/ j~>J?w9<O  
package NetFox; R6:m@  
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import java.io.*; hd[t&?{=  
import java.net.*; P"t Dq&  
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public class FileSplitterFetch extends Thread { %K7;ePu  
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String sURL; //File URL qPJSVo  
long nStartPos; //File Snippet Start Position %K06owV(S)  
long nEndPos; //File Snippet End Position +Jn\`4/J:  
int nThreadID; //Thread's ID 0ia-D`^me  
boolean bDownOver = false; //Downing is over v6E5#pse8  
boolean bStop = false; //Stop identical g:U -kK!i  
FileAccessI fileAccessI = null; //File Access interface yS[HYq  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B<$6Dj%L  
{ -%K}~4J  
this.sURL = sURL; &%k_BdlkQ  
this.nStartPos = nStart; St> E\tXp  
this.nEndPos = nEnd; Goy[P2m  
nThreadID = id; +^J;ic  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '"ze Im~  
} 5B8fz;l= B  
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public void run() v |pHbX  
{ aSJD'u4w.a  
while(nStartPos < nEndPos && !bStop) kho0@o+'^  
{ /^I!)|At  
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try{
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URL url = new URL(sURL); oYJ<.Yxeb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cf*~Gx_l  
httpConnection.setRequestProperty("User-Agent","NetFox"); JS<w43/j  
String sProperty = "bytes="+nStartPos+"-";
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httpConnection.setRequestProperty("RANGE",sProperty); $?VYHkX  
Utility.log(sProperty); qLKL*m  
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InputStream input = httpConnection.getInputStream(); -lq`EB+  
//logResponseHead(httpConnection); 0m\( @2E  
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byte[] b = new byte[1024]; ycvgF6Me<  
int nRead; BGOS(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :Dtm+EQ  
{ z8)&ekG  
nStartPos += fileAccessI.write(b,0,nRead); 8= 82x
 
//if(nThreadID == 1) =*>.z@WQ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); eu$"GbqY  
} 2 '$nz  
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{!wd5C@  
Utility.log("Thread " + nThreadID + " is over!"); U7,.L  
bDownOver = true; `bn@;7`X  
//nPos = fileAccessI.write (b,0,nRead); -*-"kzgd  
} Ys?0hd<cn  
catch(Exception e){e.printStackTrace ();} i1]}Q$  
} 62G%.'7  
} RQ#9[6w!v  
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//打印回应的头信息 /c4$m3?]  
public void logResponseHead(HttpURLConnection con) p!<PRms@  
{ )oM% N  
for(int i=1;;i++) uaCI2I  
{ c]qh)F$s8  
String header=con.getHeaderFieldKey(i); :3J`+V}9;  
if(header!=null) r/0AM}[!*j  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2n#H%&^?a  
Utility.log(header+" : "+con.getHeaderField(header)); }/IP\1bG  
else (hRg0Z=  
break; 1 .o0"  
} sqRvnCD!  
} ,zJ:a
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public void splitterStop() V{\1qg{  
{ T$;BZ=_  
bStop = true; M~Er6Zg  
} _=cuOo"!  
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} X
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/* bz [?M}  
**FileAccess.java BgB0  
*//文件访问(定位，写) [g=4'4EZc  
package NetFox; 8MBY3F  
import java.io.*; wARd^Iw  
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public class FileAccessI implements Serializable{ 8hSw4S"$  
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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 ws U@hqS  
RandomAccessFile oSavedFile; nS Vr,wU  
long nPos; 4ZYywDwn  
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};gcM@]]E  
public FileAccessI() throws IOException ]9wTAb  
{ (I{+%  
this("",0); VmXXj6l&  
} -f?,%6(1  
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public FileAccessI(String sName,long nPos) throws IOException &F'n >QT9q  
{ M`)3(|4  
oSavedFile = new RandomAccessFile(sName,"rw"); EQ"+G[j~x  
this.nPos = nPos; f/m0,EERk  
oSavedFile.seek(nPos); uw@-.N^  
} fEGnI
\  
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public synchronized int write(byte[] b,int nStart,int nLen) e YiqTWn:  
{ Ypinbej  
int n = -1; N7)K\)DS!z  
try{ x}{O9LiR  
oSavedFile.write(b,nStart,nLen); sy6[%8
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n = nLen; Q*e\I8R}  
} dkQP.Tj$i  
catch(IOException e) xlc2,L;i  
{ O6">Io5  
e.printStackTrace (); X2YBZA  
} Ak3V< =gx  
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return n; X"jtPYCpV{  
} i nk
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} ~h3~<p#M`  
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/* E7I$GD  
**SiteInfoBean.java Q+O./1x*,  
*/ e`K{  
package NetFox; \Y6r !D9  
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public class SiteInfoBean { #W4 "^#2  
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private String sSiteURL; //Site's URL ezS@`_pR;  
private String sFilePath; //Saved File's Path N).'>  
private String sFileName; //Saved File's Name J"XZnb)E=  
private int nSplitter; //Count of Splited Downloading File k/)h@K8@  
lnK#q.]  
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public SiteInfoBean() /?V-  
{//nSplitter的缺省值为5 $M$-c{>s  
//default value of nSplitter is 5 I2,AT+O<  
this("","","",5); vz&88jt  
} x]IJ;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) O.jCDAP  
{ x }]"jj2x  
sSiteURL= sURL; q w@g7  
sFilePath = sPath; U&
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sFileName = sName; RSnBG"  
this.nSplitter = nSpiltter; WS%yV|e  
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} +fQJ#?N2n  

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public String getSSiteURL() T9Fe!yVA  
{ ?}(B8^  
return sSiteURL; %8xKBL]J  
} dk0} q6~
 
{vQ:4O!:  
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public void setSSiteURL(String value) 8d&%H,  
{ }hcY5E-n  
sSiteURL = value; o4agaA3k  
} $weC '-n@  
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public String getSFilePath() sD|}?7  
{ rE0%R+4?  
return sFilePath; NPDMv |4  
} TIK'A<  
RYdI$&]  
{]$)dz5  
public void setSFilePath(String value) )_6W@s  
{ ]zn3nhBI  
sFilePath = value; Ar<!F/  
} ex66GJQe1  
"]\3t;IT  
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public String getSFileName() 8\jsGN.$JZ  
{ &=XK:+  
return sFileName; |
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} <,X=M6$0n  
+=sw&DH  
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public void setSFileName(String value) bD-OEB  
{ B>@l(e)b  
sFileName = value; M`E}1WNQ?]  
} <kWkc|zBY  
"=V!-+*@G@  
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public int getNSplitter() A2$05a$%  
{ <j3|Mh_(I  
return nSplitter; z[y
  
} v8n^~=SH  
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public void setNSplitter(int nCount) =ADOf_n}  
{ Ejnk\8:  
nSplitter = nCount; /Z[HU{4  
} ^'fgQyj  
} jmcys _N3  
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/* 2'-84  
**Utility.java %jHe_8=o  
*/ y|zIuI-p  
package NetFox; >]o>iOz;]  
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]&dPY[~,/i  
public class Utility { Q7i(M >|O  
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public Utility() ]2 $T 6  
{ `5rfO6;  
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} ).A9>^6?{  
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//线程睡眠 <0
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public static void sleep(int nSecond) ~qIr'?D  
{ Dwr 9}Z-]  
try{ xA`j:zn'j  
Thread.sleep(nSecond); *)Cr1d k  
} [;4;.V  
catch(Exception e) `xx3JQv[  
{ @|bJMi  
e.printStackTrace (); B2a#:E,6  
} /Ov1eQBNG  
} R/kJUl6HEl  
\ 9iiS(e  
//日志 5G$ ,2i(  
public static void log(String sMsg) Y*\N{6$2  
{ #dD0vYT&od  
System.err.println(sMsg); ~(7ct*U~  
} o)]O  
</1]eDnU  
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public static void log(int sMsg) jA[Ir3  
{ FSAX,Y  
System.err.println(sMsg); wG9aX*(n  
}
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} +|7N89l  
+!!G0Zj/  
K+XUC  
/* x<' $  
**TestMethod.java K=nDC.  
*/ fOME&$=O  
package NetFox; YbnXAi\y|  
ts}OE  
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public class TestMethod { C&R U  
oveK;\7/m  
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public TestMethod() VX>j2Z'  
{ ///xx/weblogic60b2_win.exe 0:<Y@#L  
try{ +."cbqGP_q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); { 0&l*@c&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &43c/TSb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +6 =lN[b  
fileFetch.start(); HtiIg a 7  
} eU,FYJt9  
catch(Exception e){e.printStackTrace ();} K"&^/[vMB  
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} ?6{g7S%  
R5%CK_  
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public static void main(String[] args) 5E1`qof  
{ -mn
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new TestMethod(); vy{k"W&S  
} VZ=:`)  
} \E<Qi3W>*  
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