http断点续传简单实现（java)

/* [@G`Afaf  
**SiteFileFetch.java S GM!#K  
*/ BJ5}GX!  
package NetFox; BQ#L+9%  
import java.io.*; j
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import java.net.*; @Y-TOCadT  
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public class SiteFileFetch extends Thread { x8"#!Pw:`"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean c!wtf,F  
long[] nStartPos; //开始位置 cj g.lzYH  
long[] nEndPos; //结束位置 Fm3t'^SqF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !9 f4R/ ?  
long nFileLength; //文件长度 r}W2Ak\  
boolean bFirst = true; //是否第一次取文件 8\Hr5FqB(  
boolean bStop = false; //停止标志 wC` R>)  
File tmpFile; //文件下载的临时信息 8omC%a}9m  
DataOutputStream output; //输出到文件的输出流 0m)&YFZ[(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） AIZBo@xg  
public SiteFileFetch(SiteInfoBean bean) throws IOException !p[`IWZ  
{ op@iGC+  
siteInfoBean = bean; _^\$"nw  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ][7p+IsB  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F]_cbM{8/  
if(tmpFile.exists ()) v(O=IUa  
{ `hrQ
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bFirst = false; cdTsRS;E  
read_nPos(); XsL#;a C  
} Vmi{X b]<  
else ~uj;qq  
{ ln<]-)&C  
nStartPos = new long[bean.getNSplitter()]; 6rX_-Mm6w  
nEndPos = new long[bean.getNSplitter()]; Xy7Z38G  
} jd:B \%#![  
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} ZjVWxQ  
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public void run() e@n!x}t8  
{ L?RF;
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//获得文件长度 2R.2D'4)`  
//分割文件 UVEz;<5@\  
//实例FileSplitterFetch J4aBPq`  
//启动FileSplitterFetch线程 ^p=L\S
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//等待子线程返回 KQ`=t  
try{ W?XizTW  
if(bFirst) 1*Ar{:+ua  
{ `G$1n#&  
nFileLength = getFileSize(); .}`hCt08  
if(nFileLength == -1) ig_2={Q@  
{ k\7:{y@,  
System.err.println("File Length is not known!"); XDz5b.,  
} ^^Jnv{)  
else if(nFileLength == -2) EKZVF`L  
{ e/s(ojDW  
System.err.println("File is not access!"); ]%dnKP~  
} :}q\tNY<  
else n(vDytrj;  
{
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for(int i=0;i<nStartPos.length;i++) ,k0r  
{ K@:m/Z}|4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); HY}j!X  
} ${hz e<g  
for(int i=0;i<nEndPos.length-1;i++) p{Sh F.  
{ ?mYYt]R  
nEndPos = nStartPos[i+1]; " I
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} m~`>`4  
nEndPos[nEndPos.length-1] = nFileLength; E4[}lX}  
} |$+5@+Zz  
} )TmtSSS  
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//启动子线程 vO@s$qi  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; lU2c_4  
for(int i=0;i<nStartPos.length;i++) 7;}l\VXHm  
{ o>lmst%<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yTBS=+X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;LwqTlJ*[L  
nStartPos,nEndPos,i); TprtE.mP  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d"Q |I
  
fileSplitterFetch.start(); $2#7D* Rx  
} NPjv)TN}3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SUtf[6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0$vj!-Mb^j  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E~hzh /,34  
nEndPos = " + nFileLength); slW3qRT\k  
// fileSplitterFetch[nPos.length-1].start(); Mi7
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*cv}*D  
//等待子线程结束 !1sU>Xb4J  
//int count = 0; k#JQxLy#  
//是否结束while循环 @gfDp<  
boolean breakWhile = false; RW7(r/C  
7C,T&g 1:  
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while(!bStop) -X1X)0v$  
{ n!ok?=(kQ  
write_nPos(); SZ!=`a]  
Utility.sleep(500); [`_io>*g  
breakWhile = true; :+&AY2`  
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for(int i=0;i<nStartPos.length;i++) HAB#pd9  
{ $#NQ<3  
if(!fileSplitterFetch.bDownOver) F} DUEDND*  
{ s
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breakWhile = false; _YHu96H;  
break; @,H9zrjVFZ  
} u5E]t9~Pq  
} Rm>^tu -  
if(breakWhile) j|(Z#3J  
break; c6AWn>H
 
;?L\Fz(<
 
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//count++; (Xxn\*S  
//if(count>4) n&XGBwgW  
// siteStop(); Qvoqx>2p5  
} g"8 .}1)~r  
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System.err.println("文件下载结束！"); +|RB0}hFS-  
} 3{Q,hpZN  
catch(Exception e){e.printStackTrace ();} lhLGG  
} 7v"lNP-?jU  
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`)>7)={  
//获得文件长度 : mGAt[Cc  
public long getFileSize() '/%zi,0  
{ UVuDQ  
int nFileLength = -1; )mcEQ-!b  
try{ fys  
URL url = new URL(siteInfoBean.getSSiteURL()); MXh "Y*}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )9j06(<A  
httpConnection.setRequestProperty("User-Agent","NetFox"); peVq+(=.  
e 9$C#D>D  

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int responseCode=httpConnection.getResponseCode(); v> z@  
if(responseCode>=400) Jobiq]|>  
{ Z@rN_WXx  
processErrorCode(responseCode); 773/#c  
return -2; //-2 represent access is error *TdnB'Gd  
} ra7uU*  
p9ZXbAJ{  
aw $L$7b}  
String sHeader; h5zVGr  
.m4;^S2cO  
j -O2aL  
for(int i=1;;i++) IO$z%r7  
{ h1"zV6U  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A7XnHPIw  
//Utility.log(in.readLine()); s4= "kT]  
sHeader=httpConnection.getHeaderFieldKey(i); /\d$/~BFi  
if(sHeader!=null) =H5\$&xj4.  
{ B0UJq./`  
if(sHeader.equals("Content-Length")) vP-M,4c  
{ I*[tMzE  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~[PKcEX  
break; rp
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} &~sfYW  
} j8,n7!G  
else Y;J*4k]  
break; x2VBm$>  
} <&!]K?Q9i  
} )|#%Czd4  
catch(IOException e){e.printStackTrace ();} rJfqA@  
catch(Exception e){e.printStackTrace ();} Lm)\Z P+W  
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Utility.log(nFileLength); =(r* 5vd  
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return nFileLength; sYbH
|}  
} nY?  
}k$4
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//保存下载信息（文件指针位置） S4NL "m  
private void write_nPos() rj
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{ e,1u  
try{ @)YY\l#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /!FWuRe^  
output.writeInt(nStartPos.length); *=F(KZ  
for(int i=0;i<nStartPos.length;i++) h\[\\m O  
{ p QE)p  
// output.writeLong(nPos); P @%.`8  
output.writeLong(fileSplitterFetch.nStartPos); x ,/TXTZ6  
output.writeLong(fileSplitterFetch.nEndPos); JHV)ZOO  
} EYS>0Y  
output.close(); `\$8`Zb;  
} Xg<[fwW  
catch(IOException e){e.printStackTrace ();} "`tX
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catch(Exception e){e.printStackTrace ();} M7}Q=q\9
 
} nY-*
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//读取保存的下载信息（文件指针位置） .=RlOK  
private void read_nPos() RNJFSD.  
{ Jn}n*t3  
try{ N_wp{4 0/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &K%aw  
int nCount = input.readInt(); cA`4:gp  
nStartPos = new long[nCount]; `H%G3M0a  
nEndPos = new long[nCount]; *7gT}O;p 5  
for(int i=0;i<nStartPos.length;i++) f4t.f*#  
{ /MTf0^9  
nStartPos = input.readLong(); _2Zp1h,  
nEndPos = input.readLong(); %CH6lY=lI  
} }6m?d!m  
input.close(); $xW**&  
} >9K//co"of  
catch(IOException e){e.printStackTrace ();} X)Gp7k1w  
catch(Exception e){e.printStackTrace ();} 7} O;FX+x  
} Buc_9Kzw<+  
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private void processErrorCode(int nErrorCode) = 1|"-  
{ )/t6" "  
System.err.println("Error Code : " + nErrorCode); p]|LV)R n  
} D_D,t8_Y  
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//停止文件下载 MiGcA EF;  
public void siteStop() n'w,n1z7  
{ w9&#~k]5  
bStop = true; wq0aF"k  
for(int i=0;i<nStartPos.length;i++) N+Sq}hI  
fileSplitterFetch.splitterStop(); s;.=5wcvi?  
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} G2Qjoe`Uc  
} DZ`k[Z.VZ  
//负责部分文件的抓取 Gp2!xKgm  
**FileSplitterFetch.java v<h;Di@  
*/ ;bjnL>eW  
package NetFox; z1j|E :  
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import java.io.*; F@SG((`  
import java.net.*; y:so L:(F  
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public class FileSplitterFetch extends Thread { 5P+YK\~  
3E|;r _; 8  
{BOLPE-  
String sURL; //File URL iCi>zJ  
long nStartPos; //File Snippet Start Position SGf9U^ds  
long nEndPos; //File Snippet End Position 6Z
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int nThreadID; //Thread's ID )x\z@g  
boolean bDownOver = false; //Downing is over &HF]\`RNr  
boolean bStop = false; //Stop identical +V
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FileAccessI fileAccessI = null; //File Access interface htHv&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException K2|7%  
{ |5ONFde"0  
this.sURL = sURL; ~ x`7)3  
this.nStartPos = nStart; eP|)SU  
this.nEndPos = nEnd; K-@bwB7~s  
nThreadID = id; ua#K>sur.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 OmNn,PCl8  
} _S5gcPcF"  
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public void run() <!!nI%NC  
{ HD00J]y_   
while(nStartPos < nEndPos && !bStop) 4x]NUt  
{ 6Ct0hk4  
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try{ :uvc\|:s  
URL url = new URL(sURL); m/?h2McS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~XQ$aRl&  
httpConnection.setRequestProperty("User-Agent","NetFox"); NcM3P 
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String sProperty = "bytes="+nStartPos+"-"; XGk}e4;_  
httpConnection.setRequestProperty("RANGE",sProperty); Fwv\pJ}$  
Utility.log(sProperty); y:9?P~  
nKu(XgFv  
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InputStream input = httpConnection.getInputStream(); }200g_^  
//logResponseHead(httpConnection); #M:B3C!ouY  
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byte[] b = new byte[1024]; L9J;8+ge  
int nRead; gvr]]}h:O  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a
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{ J/[7d?hI/  
nStartPos += fileAccessI.write(b,0,nRead); \E&thp  
//if(nThreadID == 1) Zh? V,39  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .h6Y<
E  
} wRi~Yb?  
[oJ& J>U'  
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Utility.log("Thread " + nThreadID + " is over!"); VO|u8Z"  
bDownOver = true; d'q&Lq  
//nPos = fileAccessI.write (b,0,nRead); NY
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} w(#:PsMo<  
catch(Exception e){e.printStackTrace ();} Xky@[Td*  
} C=s((q*  
} {[lx!QF 8&  
C#T)@UxBZ  
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//打印回应的头信息 qw)Key  
public void logResponseHead(HttpURLConnection con) P;>!wU~*  
{ 'N|2vbi<  
for(int i=1;;i++) xpz`))w  
{ flPZlL  
String header=con.getHeaderFieldKey(i); sB8p( L  
if(header!=null) W=F3XYS  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); eA10xpM0
 
Utility.log(header+" : "+con.getHeaderField(header)); pj j}K  
else 37~rm  
break; <G&WYk%u*  
} %{Xm5#
m  
} c.\:peDk  
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public void splitterStop() D. 77WjwQ  
{ E=A/4p6\$  
bStop = true; ~;TV74~rr  
} ^NcTWbs-T  
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} ZjE~W>pkQ  
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/* oJhEHx[f  
**FileAccess.java :U7;M}0
 
*//文件访问(定位，写) TeOFAIU  
package NetFox; cPx66Dh&  
import java.io.*; (2n3exx  
x/pC%25  
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public class FileAccessI implements Serializable{ c>M_?::)0  
4mki&\lw`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4&#vU(-H  
RandomAccessFile oSavedFile; r7zf+a]  
long nPos; M|5^':Y  
^w.k^U=B  
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public FileAccessI() throws IOException A)=X?x  
{ 
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this("",0); O<gP)ZW~  
} ,"4X&>_f  
fJ,8g/f8  
5;r({J  
public FileAccessI(String sName,long nPos) throws IOException !.x=r  
{ rCV$N&rK  
oSavedFile = new RandomAccessFile(sName,"rw"); ?14X8Mb8W_  
this.nPos = nPos; ={e#lC  
oSavedFile.seek(nPos); Yqq$kln  
} :/I={)5  
y}.y,\S0  
Ktj(&/~}  
public synchronized int write(byte[] b,int nStart,int nLen) 1K
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{ 2nOe^X!*  
int n = -1; p1[WGeV  
try{ F!DrZd>\  
oSavedFile.write(b,nStart,nLen); L>|A6S#y8/  
n = nLen; @pyA;>U  
} B)LXxdkOn  
catch(IOException e) PDa0
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{ ?L.p9o-S0  
e.printStackTrace (); HvL9;^!  
} crF9,p  
cc#_acR  
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return n; 2gNBPd)I  
} ~=aI2(b  
h_}BmJh_  
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} 5}(YMsUb  
1[,#@!k@  
kgib$t_7  
/* ~vvQz"  
**SiteInfoBean.java ?PH}b?f4  
*/ CMD`
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package NetFox; x#!{5;V&K  
:D)&>{?  
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public class SiteInfoBean { %)!~t8To  
RI<Yg#  
~P.-3  
private String sSiteURL; //Site's URL 4h0jX9  
private String sFilePath; //Saved File's Path 88X*:Kf?:  
private String sFileName; //Saved File's Name )QJU
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private int nSplitter; //Count of Splited Downloading File }][|]/s?42  
hwb(W?*  
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public SiteInfoBean() I
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{//nSplitter的缺省值为5 |'>E};D  
//default value of nSplitter is 5 clU3#8P!=  
this("","","",5); hghto \G5Y  
} 4wEpyQ|L  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) HZ`G)1&)  
{ F(kRAe;  
sSiteURL= sURL; s9Q)6=mE  
sFilePath = sPath; ^zs4tCW%  
sFileName = sName; `EW_pwZPA  
this.nSplitter = nSpiltter; , $F0D  
N
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} H<}Fk9  
lDM~Z3(/b  
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public String getSSiteURL() _WkcJe`  
{ 7Mbt*[n  
return sSiteURL; >rX R;4%  
} f0`rJ?us  
5WNRo[`7  
}\qdow-  
public void setSSiteURL(String value) &JQ@(w  
{ S5JR`o
 
sSiteURL = value; ReGb.pf  
} /8-VC"  
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.KMi)1L)  
public String getSFilePath() 4oEq,o_  
{ GP kCgb(  
return sFilePath; h[)aRo  
} 4 ~|TKd{  
.6A:t?.  
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public void setSFilePath(String value) a/`Yh>ou  
{ |ssIUJ  
sFilePath = value;
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} X!+ a;wr  
,$(v#Tz  
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public String getSFileName() vrldRn'*9  
{ uTloj.  
return sFileName; aI#n+PW  
} %Yn)t3d  
gBS#Z.  
;Z~.54Pf{d  
public void setSFileName(String value) F0(Sv\<::  
{ eBRP%<=>D  
sFileName = value; 2%yJo7f$[  
} U@AfRUF&  
h*LL(ow5  
N~KRwsDH  
public int getNSplitter() zjZTar1Re  
{ (#"s!!b  
return nSplitter; m8A_P:MQq  
} >43yty\   
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/'_ RI  
public void setNSplitter(int nCount) /6*.%M>r  
{ #\["y%;W  
nSplitter = nCount; ^<Tp-,J$EN  
} y$Noo)Z  
} %4KJ&R (>[  
e%Xf*64  
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/* EKw\a  
**Utility.java ">&:(<  
*/ (`Mz.VN  
package NetFox; ?YykCJJ ~@  
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public class Utility { bbkI}d%(Ng  
>U/g*[>  
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public Utility() z$5C(!)  
{ 3pH`]m2  
{xoo9jq-  
xAE@cwg  
} EZfa0jJD  
ck+rOGv7{Z  
//线程睡眠 f)P/@rh  
public static void sleep(int nSecond) 6+z]MT  
{ i)3\jO0&GU  
try{ `\0a5UFR  
Thread.sleep(nSecond); "uC*B4`  
} K7VG\
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catch(Exception e) e.^9&Fk"N  
{ ~{Bi{aK2  
e.printStackTrace (); -;-"i J0  
} B'/ >Ax&  
} 0.0!5D[  
1hS~!r'qqv  
//日志 R!qrb26k  
public static void log(String sMsg) Z$XpoDbOy  
{ &/?jMyD@  
System.err.println(sMsg); !l^AKn|  
} ~mU_`o  
kR(=VM JU  
O3Mv"Py%  
public static void log(int sMsg) nHrCSfK  
{ jtY~-@*  
System.err.println(sMsg); VAt9JE;#  
} H12@12v  
} 8E[`H  
1z:N$O_v  
V~Lq,oth  
/* sR.j~R  
**TestMethod.java .&xNJdsY  
*/ 8m<<tv
.  
package NetFox; dhkpkt<G8  
sdD[`#  
IBh~(6  
public class TestMethod { R!G7;m'N1  
Yk?q7xuT  
xrnH=>.;m  
public TestMethod() Y1\vt+`O  
{ ///xx/weblogic60b2_win.exe 0&@pX~h:  
try{ c<e\JJY5?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); AoeW<}MO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -5.%{Go$[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |hoZ:  
fileFetch.start(); qT @IY)e  
} f tDV3If  
catch(Exception e){e.printStackTrace ();} k;7.qhe:  
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_6 `4_<c=  
} pnJT]?},  
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,eCXT=6  
public static void main(String[] args) @D=`iG%  
{ 7d)' y  
new TestMethod(); eUlb6{!y?  
} B,,d~\  
} >,Z{wxzJ  
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