http断点续传简单实现（java)

/* G+5G,|}  
**SiteFileFetch.java nP0}vX)<  
*/ w.0.||C O  
package NetFox; L8Z?B\  
import java.io.*; 2$3BluK  
import java.net.*; wmoOp;C  
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public class SiteFileFetch extends Thread { 8q0f#/`v  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8#oF7
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long[] nStartPos; //开始位置 89 SsSb  
long[] nEndPos; //结束位置 *|`'L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }1$8)zH  
long nFileLength; //文件长度 j*6!7u.,K  
boolean bFirst = true; //是否第一次取文件 )3u[btm  
boolean bStop = false; //停止标志 VK|!aqA{b  
File tmpFile; //文件下载的临时信息 ?X:RrZ:/  
DataOutputStream output; //输出到文件的输出流 wOa_"  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |\}f)Xp-  
public SiteFileFetch(SiteInfoBean bean) throws IOException Um9=<*p  
{ 525xm"Bs  
siteInfoBean = bean; sH&8"5BT%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "= %-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n_c0=YH  
if(tmpFile.exists ()) 50'6l X(v,  
{ 1hMk\ -3S  
bFirst = false; *tP,Ol  
read_nPos(); / Sp+MB9  
} r+Z+x{  
else QeQbO  
{ w]%r]PwU+  
nStartPos = new long[bean.getNSplitter()]; Sa<R8X'J  
nEndPos = new long[bean.getNSplitter()]; vJcvyz#%1  
} nl?|X2?C  
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} s ^}V  
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public void run() g6*}&.&  
{ Dic(G[  
//获得文件长度 xr?r3Y~^e  
//分割文件 bRIb'%=+GA  
//实例FileSplitterFetch i?|SC=  
//启动FileSplitterFetch线程 ?dTz?C.w  
//等待子线程返回 "5YsBih  
try{ *
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if(bFirst) MQ,2v. vZ.  
{ =lffr?#&B  
nFileLength = getFileSize(); 2s(K4~ee  
if(nFileLength == -1) {uhw ^)v  
{ &0o&!P8CB  
System.err.println("File Length is not known!"); w!xSYh')  
} }y0UyOa{C  
else if(nFileLength == -2) *k=}g][?  
{
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System.err.println("File is not access!"); ao,LP,_  
} +6TKk~0e^  
else XCt}>/"s\h  
{ f^]2qoN  
for(int i=0;i<nStartPos.length;i++) >M +!i+  
{ T&{EqsI=B  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _=cMa's  
} Oi{jzP  
for(int i=0;i<nEndPos.length-1;i++) TRQva8d?  
{ \C>I6{  
nEndPos = nStartPos[i+1]; q= tDMK'h  
} 5ax/jd~}  
nEndPos[nEndPos.length-1] = nFileLength; \dCdyl6V  
} !u=[/>  
} 5&VLq  
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hio{
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//启动子线程 6x.#K9@q4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p2cKtk+  
for(int i=0;i<nStartPos.length;i++) dpE+[O_  
{ b0 5h,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .E@yB`AR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {Ji[d.cY  
nStartPos,nEndPos,i); 2R)Y}*VX  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vk$]$6l2  
fileSplitterFetch.start(); 9BF#R<}h  
} KBOxr5w  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qUVV374N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _jr%s  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;[*7UE+#7  
nEndPos = " + nFileLength); gTs5xDvJ  
// fileSplitterFetch[nPos.length-1].start(); M~^|dR)D  
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//等待子线程结束 ;Cv x48  
//int count = 0; m'a3}vRV(  
//是否结束while循环 [P"#?7 N  
boolean breakWhile = false; (m@({  
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while(!bStop) 0Y[mh@(  
{ 4aiI&,  
write_nPos(); b%QcB[k[WB  
Utility.sleep(500); g)1`A24  
breakWhile = true; yBRYEqS+  
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for(int i=0;i<nStartPos.length;i++) 6)veuA3]  
{ b~*CJ8Ad  
if(!fileSplitterFetch.bDownOver) $x*(D|\'<  
{ X7rsO^}W  
breakWhile = false; LP'wL6#  
break; ]1 jhy2j  
} mndKUI}d  
} ||))gI`3a  
if(breakWhile) |s,y/svp  
break; X4<Y5?&0  
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//count++; Qb5@e#  
//if(count>4) &I:ZJuQ4  
// siteStop(); Ig<# {V  
} iwy;9x  
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System.err.println("文件下载结束！"); 4t-l@zFWb  
} hEFOT]P4  
catch(Exception e){e.printStackTrace ();} @*E=O|  
} ME66B
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M.HMnN#  
//获得文件长度 <U
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public long getFileSize() yJ="dEn>i"  
{ {:|b,ep T  
int nFileLength = -1; "|Kag|(qB  
try{ }kF?9w  
URL url = new URL(siteInfoBean.getSSiteURL()); kE:{#>[Uz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6Jq3l_  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3~{0X-  
1IlOU|
4  
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int responseCode=httpConnection.getResponseCode(); X:lStO#5  
if(responseCode>=400) 8rjD1<  
{  d0i|^  
processErrorCode(responseCode); 7%W1M@  
return -2; //-2 represent access is error a`[9<AM1#  
} Uy.ihh$I-  
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String sHeader; 7<Qmpcp =  
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for(int i=1;;i++) 8.>himL  
{ M%Ksyr9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
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//Utility.log(in.readLine()); 0m=57c$O  
sHeader=httpConnection.getHeaderFieldKey(i); r6R@"1/  
if(sHeader!=null) L^zh|MEyzk  
{ T--%UZD]W  
if(sHeader.equals("Content-Length")) CUHT5J*sY  
{ nt+OaXe5D  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m=
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break; qGX#(,E9;  
} )0]U"Nf ho  
} Dx`-h#  
else 5@-H8*  
break; hSR+7qN<e  
} `uUzBV.FR  
} kN78j  
catch(IOException e){e.printStackTrace ();} "*.N'J\  
catch(Exception e){e.printStackTrace ();} lGBg8/[  
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Utility.log(nFileLength); uo J0wG.  
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return nFileLength; Kvo&_:  
} HZZZ [km  
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//保存下载信息（文件指针位置） >*VvV/UU  
private void write_nPos() >X eXd{$  
{ 'vZIAnB8  
try{ R y#
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output = new DataOutputStream(new FileOutputStream(tmpFile)); 86N,04  
output.writeInt(nStartPos.length); 83SK<V6  
for(int i=0;i<nStartPos.length;i++) }8#Ed;%K  
{ u~j H  
// output.writeLong(nPos); d+,!p8Q  
output.writeLong(fileSplitterFetch.nStartPos); "mQcc}8  
output.writeLong(fileSplitterFetch.nEndPos); @$n $f  
} `6J7c;:  
output.close(); 0bM_EC  
} 2/folTR7  
catch(IOException e){e.printStackTrace ();} h!K" ;qw  
catch(Exception e){e.printStackTrace ();} zMu9A|  
} qar{*>LCG  
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v9-4yZU^WR  
//读取保存的下载信息（文件指针位置） 7~XA92  
private void read_nPos() t_w\k_ T  
{ 6>rz=yAM_  
try{ \ *[Ht!y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7T
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int nCount = input.readInt(); jIT|K
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nStartPos = new long[nCount]; 0VtjVz*C7&  
nEndPos = new long[nCount]; ]"uG04"Vk  
for(int i=0;i<nStartPos.length;i++) g"5Kth  
{ v0oVbHO5<  
nStartPos = input.readLong(); >pLJ ,Z  
nEndPos = input.readLong(); SfC* ZM}
<  
} %p )"_q!ge  
input.close(); 1b3k|s4   
} \DS*G7.A+&  
catch(IOException e){e.printStackTrace ();} 4tLdqs  
catch(Exception e){e.printStackTrace ();} J.R\h!  
} ygIn6
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private void processErrorCode(int nErrorCode) @ewaj!  
{ *cXq=/s  
System.err.println("Error Code : " + nErrorCode); :G@z?ZJ[  
} <hCO-r#  
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|{kbc0*  
//停止文件下载 k-=lt\?  
public void siteStop() xH:L6K/c  
{ w=;>  
bStop = true; SgewAng?@o  
for(int i=0;i<nStartPos.length;i++) [?I<$f"  
fileSplitterFetch.splitterStop(); 3{?X>6T  
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} ao9#E"BfM  
} UMRF
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//负责部分文件的抓取 4E5;wH  
**FileSplitterFetch.java NJsaTBT  
*/ mbkt7. ,P  
package NetFox; KF+r25uy[+  
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import java.io.*; %Hd[,duwO  
import java.net.*; N? Jy  
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public class FileSplitterFetch extends Thread { <`pNdy4  
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String sURL; //File URL ;km`P|
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long nStartPos; //File Snippet Start Position wcrCEX=I>{  
long nEndPos; //File Snippet End Position U$O\f18  
int nThreadID; //Thread's ID \r/rBa\  
boolean bDownOver = false; //Downing is over du<tGsy  
boolean bStop = false; //Stop identical g;H=6JeG/  
FileAccessI fileAccessI = null; //File Access interface t|w_i-&b,  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /74QMx?  
{ 8f_l}k$Eg  
this.sURL = sURL; Mc?Qx  
this.nStartPos = nStart; 4(#'_jS  
this.nEndPos = nEnd; MS nG3]{z  
nThreadID = id; cb@?}(aFl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 y|jl[pyg)  
} ~G)S   
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public void run() df*#!D7oz  
{ Fh)IgzFj  
while(nStartPos < nEndPos && !bStop) eJrQ\>z]V&  
{ kq?Ms|h  
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try{ rbul8(1h  
URL url = new URL(sURL); `oAW7q)~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 99]R$eT8  
httpConnection.setRequestProperty("User-Agent","NetFox"); }cM}Oavh  
String sProperty = "bytes="+nStartPos+"-"; x/%aM1"X^  
httpConnection.setRequestProperty("RANGE",sProperty); @tF\p  
Utility.log(sProperty); AL[KpY  
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InputStream input = httpConnection.getInputStream(); ]v?@g:iE  
//logResponseHead(httpConnection); ?#Ge.D~u  
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byte[] b = new byte[1024]; +<'Ev~  
int nRead; _PPy44r2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) S};#+ufgTt  
{ !zBhbmlKt  
nStartPos += fileAccessI.write(b,0,nRead); 2Zm0qJ  
//if(nThreadID == 1) <g-9T-Ky  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nz%DM<0$  
} 3W V"U  
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Utility.log("Thread " + nThreadID + " is over!"); j*d yp  
bDownOver = true; \S_Ou   
//nPos = fileAccessI.write (b,0,nRead); j 'FVz&  
} qjc8fP2  
catch(Exception e){e.printStackTrace ();} i|c'Lbre`  
} *FWMn.  
} mD/9J5:  
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) g0%{dfJ  
//打印回应的头信息 0mpX)S  
public void logResponseHead(HttpURLConnection con) FO+Zue.RS  
{ \j+1V1t9  
for(int i=1;;i++) |<HPn4 ,X  
{ \4&
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String header=con.getHeaderFieldKey(i); &@G:G(  
if(header!=null) Z.c'Hs+;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t=rEt>n~L  
Utility.log(header+" : "+con.getHeaderField(header)); . kQkC:~9  
else 3Q"<<pi!~  
break; *,3SGcYdJj  
} ,
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} N<|@ymi  
}
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public void splitterStop() rw: c  
{ Q(@U2a8  
bStop = true; Z?}dq-Vh&  
} MTsM]o  
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} XaCX!Lr,  
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/* |K6REkzr  
**FileAccess.java aa?w:3  
*//文件访问(定位，写) Y<mej][  
package NetFox; v5By:z  
import java.io.*; "$N#p5  
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public class FileAccessI implements Serializable{ Pdt6nzfr  
0}$Hi  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 I 6<*X  
RandomAccessFile oSavedFile; p /#$io  
long nPos; XLAN Np%E  
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public FileAccessI() throws IOException )=AHf?hn  
{ y($%;l   
this("",0); JMH8MH*  
} >TQH|}|6(y  
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public FileAccessI(String sName,long nPos) throws IOException L ]w/P|  
{ =li|  
oSavedFile = new RandomAccessFile(sName,"rw"); |b*? qf  
this.nPos = nPos; o>7ts&rk  
oSavedFile.seek(nPos); B<~ NS)w  
} J,zO2572u  
1}tbH[  
.N*Pl(<[  
public synchronized int write(byte[] b,int nStart,int nLen) $d,0=Ci  
{ F35#dIs`&  
int n = -1; JqMDqPIQ  
try{ N
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oSavedFile.write(b,nStart,nLen); C#H:-Q&  
n = nLen; \TF!S"V  
} ;>AL`M+  
catch(IOException e) SL,p36N  
{ MdXchO-Lyc  
e.printStackTrace (); I8QjKI (  
} a\%xB >LX  
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=&dW(uyzY  
return n; muW!xY  
} dJ:MjQG`W  
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} O9(r{Vu7u  
|KYEK|  
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/* OOBhbpg!D  
**SiteInfoBean.java (!5LW'3B  
*/ to"'By{9  
package NetFox; L?Yoh<  
`N/RHb%  
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public class SiteInfoBean { +]:2\TTGI  
7:NmCpgL!  
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private String sSiteURL; //Site's URL ftk%EYT;  
private String sFilePath; //Saved File's Path RE3Z%;'  
private String sFileName; //Saved File's Name iP3Z  
private int nSplitter; //Count of Splited Downloading File Dbx~n#nG  
w(nHD*nm  
s|bM%!$1  
public SiteInfoBean() p3^jGj@  
{//nSplitter的缺省值为5 $\a5&1rl  
//default value of nSplitter is 5 ^4v*W;Q  
this("","","",5); Q}A=jew  
} V_U'P>_I  
ps:f=6m2  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %bb~Y"  
{ Bz
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sSiteURL= sURL; (3,.3)%`  
sFilePath = sPath; J?:[$C5  
sFileName = sName; GgFi9F
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this.nSplitter = nSpiltter; o5Rz%k#h  
'3l$al:H^  
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} 10sK]XI  
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public String getSSiteURL() e5
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{ ? S=W&  
return sSiteURL; :_dICxaLZT  
} q(z7~:+qNr  
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public void setSSiteURL(String value) FY;+PY@I{  
{ uf)Oy7FQ  
sSiteURL = value; d}0qJoH4  
} Db03Nk>#  
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j^u[F"  
public String getSFilePath() aCi^^}!  
{ :6k DUFj}
 
return sFilePath; b}L,kT  
} i`nw"8  
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i  
|Sv#f2`  
public void setSFilePath(String value) iN4'jD^oP  
{ @$yYljP  
sFilePath = value; 6`";)T[G9  
} f uNXY-;  
9c %Tv  
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public String getSFileName() |j}F$*SE[  
{ wBHDof xX  
return sFileName; zomNjy*  
} u\geD  
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public void setSFileName(String value) khIa9Nm  
{ >@Vr'kg+V
 
sFileName = value; j"u)
/A8*  
} v]U;5Uo  
~%:p_td  
DMN H?6  
public int getNSplitter() \\Tp40m+  
{ gbf=H8]  
return nSplitter; *9(1:N;#  
} ykhCt\t[  
[gp:nxyfQm  
ly%B!P|  
public void setNSplitter(int nCount) rg/vxTl  
{ emPm^M5/K
 
nSplitter = nCount; Bic { H  
} 0%NI- Zyo  
} :Rj,'uH+h)  
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/* 6|cl`}g_j  
**Utility.java i4rF~'h@  
*/ $i>VI  
package NetFox; P$Ru NF  
|raQ]b@t&  
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public class Utility { (r\h dLX  
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public Utility() bR,Iq}p  
{ ITlkw~'G  
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{.9phW4Vr?  
} 0*^)n&O  
LPbZ.  
//线程睡眠 PezUG{q(  
public static void sleep(int nSecond) w5"C<5^  
{
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try{ 11}fPWK  
Thread.sleep(nSecond); .fxI)  
} ?4=8z8((!  
catch(Exception e) ouKID_'  
{ qPdNI1 |  
e.printStackTrace (); EzY?=<Y(  
} x#"|Z&Dw0  
} WAiEINQ^)  
;=7z!:)  
//日志 JNu- z:J  
public static void log(String sMsg) Gg!))I+  
{ .Yf h*  
System.err.println(sMsg); fC-^[Af)  
} b9YpUm7#  
6 %=BYDF  
tS9m8(Hr%Q  
public static void log(int sMsg) H,I}R  
{ !7oy%{L  
System.err.println(sMsg); uI2'jEjO  
} (HI%C@e9  
} p5l$On  
4I*Mc%dD  
s]c$]&IGG  
/* 8:% R|b  
**TestMethod.java f'6qJk%J  
*/ 2Cd --W+=  
package NetFox; 0?F@iB~1F  
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c[h'`KXJf-  
public class TestMethod { 9\>sDSCx  
_q)!B,y-/N  
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public TestMethod() %
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{ ///xx/weblogic60b2_win.exe 2tf6GX:  
try{ N_G4_12(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); W2eAhz&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A,BEKjR~J  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "OL~ul5  
fileFetch.start(); *d>vR1  
} bxwk
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catch(Exception e){e.printStackTrace ();} /.$L"u  
rl?7W];  
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} :<GfETIs  
jK3\K/ob(  
*vnXlV4L  
public static void main(String[] args) ;JTt2qQKo  
{ WFv!Pbq,  
new TestMethod(); FxW&8 9G  
} 8OFj0S1r`  
} 4^Rd{'mt  
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