http断点续传简单实现（java)

/* Aars\   
**SiteFileFetch.java v;\cM/&5  
*/ RFRX
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package NetFox; ?xqS#^Z  
import java.io.*; !+eU  
import java.net.*; !K(  
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public class SiteFileFetch extends Thread { :%h1Q>F  
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SiteInfoBean siteInfoBean = null; //文件信息Bean .T3N"}7[  
long[] nStartPos; //开始位置 )vO"S  
long[] nEndPos; //结束位置 5@xR`g-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F\r"Y)|b=  
long nFileLength; //文件长度 "d)YqQ  
boolean bFirst = true; //是否第一次取文件 K@7%i|H  
boolean bStop = false; //停止标志 U*~-\jN1pb  
File tmpFile; //文件下载的临时信息 , @jtD*c)  
DataOutputStream output; //输出到文件的输出流 MAYb.>X#>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） R:f!ywj%  
public SiteFileFetch(SiteInfoBean bean) throws IOException <XLaJ;j  
{ :"Xnu%1  
siteInfoBean = bean; [QxP9EC  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )!-gT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]_(hUj._  
if(tmpFile.exists ()) Sesdhuy.@  
{ lW?}Ts~'  
bFirst = false; q7lC}'2fu  
read_nPos(); k( Sda>-  
} e#/&A5#Ya  
else QwX81*nx  
{ znE1t%V  
nStartPos = new long[bean.getNSplitter()]; dXxf{|gk>  
nEndPos = new long[bean.getNSplitter()]; _$R=F/88  
} >h8m)Q  
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} ?L0;, \-t  
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public void run() gfK_g)'2U  
{ +\Vw:
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//获得文件长度 [@9S-$Xa  
//分割文件 _{`Z?lt  
//实例FileSplitterFetch >s5}pkAv|e  
//启动FileSplitterFetch线程 32K& IfV  
//等待子线程返回 FXo.f<U  
try{ h)Fc<,vwBE  
if(bFirst) BX$<5S@  
{ "a2|WKpD  
nFileLength = getFileSize(); 4vbGXb}!  
if(nFileLength == -1)
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{ -]
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System.err.println("File Length is not known!");
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} Y#c439&  
else if(nFileLength == -2) MtL<)?HQ  
{ %j^QK>%  
System.err.println("File is not access!"); 8$~oiK%fw  
} @ovaOX  
else we_CF*zj  
{ ]AA|BeL?|  
for(int i=0;i<nStartPos.length;i++) !AXLoq$SY  
{ >0@w"aKn  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); R|*0_!O:[  
} CtMqE+j^  
for(int i=0;i<nEndPos.length-1;i++)
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{ {x
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nEndPos = nStartPos[i+1]; We$ n  
} 9~`#aQG T  
nEndPos[nEndPos.length-1] = nFileLength; BeFyx"NBg  
} bhpaC8|  
} f~W+Rt7o  
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//启动子线程 C:No ^nH>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =-Hhm($n  
for(int i=0;i<nStartPos.length;i++) .I~:j`K6  
{ ?<jWEz=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s3sRMB2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2z{B  
nStartPos,nEndPos,i); N4;g
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,j XK  
fileSplitterFetch.start(); O>~@>/#  
} |aenQA#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JYWoQ[ZO#>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )A*53>JV  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", c<Cf|W  
nEndPos = " + nFileLength); p^ (Z  
// fileSplitterFetch[nPos.length-1].start(); P Ptmh. }e  
|a03SZx  
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//等待子线程结束 &S xF"pYV  
//int count = 0; Zq
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//是否结束while循环 fNi&r0/-t  
boolean breakWhile = false; ,ASNa^7/>  
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while(!bStop)  d;>G  
{ 47(_5PFb#  
write_nPos(); odca?  
Utility.sleep(500); jR}EBaI}  
breakWhile = true; /1Gmga5  
#W8F_/!n|  
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for(int i=0;i<nStartPos.length;i++) JYj*.Q0  
{ WYF8?1dt +  
if(!fileSplitterFetch.bDownOver) FR6 W-L  
{ ;+C$EJw-  
breakWhile = false; GXm#\)  
break; (b~l.@xh  
} \},H\kK+^  
} QlvP[Jtr  
if(breakWhile) BPv+gx(>k  
break; Pqx?0f)  
jY\z+lW6A  
>{{ds--  
//count++; Fc[vs5
2  
//if(count>4) mCt/\  
// siteStop(); \mLEwNhRY  
} `W}pAmhj  
'^m'r+B"  
Ps.xY;Y  
System.err.println("文件下载结束！"); FVkl#Qy~  
} 5uG^`H@X  
catch(Exception e){e.printStackTrace ();} NsYEBT7f  
} P9m
  
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//获得文件长度 PeIi@0vA  
public long getFileSize() j]&
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{ GU`q^q@Ea  
int nFileLength = -1; 68GH$ji  
try{ 0xDn!  
URL url = new URL(siteInfoBean.getSSiteURL()); m{ani/bt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l"JM%LV  
httpConnection.setRequestProperty("User-Agent","NetFox"); Hd;NvNS  
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int responseCode=httpConnection.getResponseCode(); {hN\=_6*EW  
if(responseCode>=400) m4h)Wq  
{ M 2| k.  
processErrorCode(responseCode); b=S"o )>  
return -2; //-2 represent access is error zQ:nL*X'Z"  
} &a'mG=(K_c  
p:b{>lM  
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String sHeader; +JG05h%'  
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for(int i=1;;i++) k(tB+k!vH\  
{ o=94H7@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (rJ-S"^u  
//Utility.log(in.readLine()); yuC$S&Y>!  
sHeader=httpConnection.getHeaderFieldKey(i); 6d8)]  
if(sHeader!=null) L"vk ^>E6  
{ N/WtQSl  
if(sHeader.equals("Content-Length")) }@6yROy.  
{ Q)4[zStR#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); GQ?FUFuIoW  
break; !wE% <Fh  
} >pZ_  
} %"c;kvw  
else <(TAA15Xol  
break; Ep;?%o,G  
} jTqJ(M}L  
} i
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catch(IOException e){e.printStackTrace ();} c{to9Lk.#  
catch(Exception e){e.printStackTrace ();} Cp!9 "J:  
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Utility.log(nFileLength); jqvw<+#  
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return nFileLength; s\3]0n9  
} c8]%,26.  
h*KDZ+{)  
ik?IC$*n3i  
//保存下载信息（文件指针位置） ^y ', l  
private void write_nPos() B!`.,3  
{ BQUYT/$(  
try{ >Giw\|:f(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); jxW/"Q   
output.writeInt(nStartPos.length); xS/=9l/G  
for(int i=0;i<nStartPos.length;i++) X`&Us  
{ n::i$ZUdK  
// output.writeLong(nPos); =;n>#<  
output.writeLong(fileSplitterFetch.nStartPos); `_/1zL[  
output.writeLong(fileSplitterFetch.nEndPos); _"D J|j  
} }Gb^%1%M  
output.close(); 1$# r)S[*  
} <oP`\m  
catch(IOException e){e.printStackTrace ();} 0)PZS>  
catch(Exception e){e.printStackTrace ();} ZR3sz/ulLd  
} gjK: a@{  
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uCW}q.@4  
//读取保存的下载信息（文件指针位置） Q$'\_zV  
private void read_nPos() ;>>:7rdYt  
{ H.n|zGQTB  
try{ GRL42xp'*D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6,CK1j+tZ  
int nCount = input.readInt(); Yx. t+a-  
nStartPos = new long[nCount]; #0*I|gfV  
nEndPos = new long[nCount]; n|=yw6aV'  
for(int i=0;i<nStartPos.length;i++) b!SIs*  
{ V^.Z&7+E`_  
nStartPos = input.readLong(); 2&s(:=  
nEndPos = input.readLong(); T|oDJ]\J  
} /YwwG;1  
input.close(); Z^mIGy}  
} %^I
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catch(IOException e){e.printStackTrace ();} ,-$%>Uv  
catch(Exception e){e.printStackTrace ();} NJ}xqg  
} <;b  
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private void processErrorCode(int nErrorCode) S
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{ hZe9Y?)  
System.err.println("Error Code : " + nErrorCode); 3PzF^8KJ  
} )086u8w )y  
bX`]<$dr3  
xU.Ymq& 5  
//停止文件下载 aeLIs SEx  
public void siteStop() S +73 /Vs  
{ bw#\"uJ  
bStop = true; s5d[sx  
for(int i=0;i<nStartPos.length;i++) tUfze9m  
fileSplitterFetch.splitterStop(); odcrP\S  
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blbzh';0}  
} '
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} nM$-L.dG  
//负责部分文件的抓取 @M }`nKXM  
**FileSplitterFetch.java +x:VIi  
*/ y(K:,CI  
package NetFox; gd31ds!G  
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import java.io.*; -cXVkH{  
import java.net.*; E&W4`{6K4  
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public class FileSplitterFetch extends Thread { y3V47J2o  
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.|kp`-F51  
String sURL; //File URL Ce3  
long nStartPos; //File Snippet Start Position uUG&At  
long nEndPos; //File Snippet End Position V SH64  
int nThreadID; //Thread's ID CBx5:}t  
boolean bDownOver = false; //Downing is over |-AR)Smt  
boolean bStop = false; //Stop identical c*>SZ'T\  
FileAccessI fileAccessI = null; //File Access interface yF&?gPh&  
[;INVUwG^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException I1Gk^wO  
{ ;{>-K8=>$  
this.sURL = sURL; b
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this.nStartPos = nStart; vC5 (  
this.nEndPos = nEnd; z1~U#  
nThreadID = id; Q#$dp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;%i.@@:IQ  
} xF9PjnWF=  
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public void run() }JWk?  
{ &]'<M  
while(nStartPos < nEndPos && !bStop) I03 45Hc  
{ [Hp"a^~r|  
}"c
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)N&v.w  
try{ ] i\a[3  
URL url = new URL(sURL); ;6zp,t0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?#;zB  
httpConnection.setRequestProperty("User-Agent","NetFox"); [+$o`0q;N?  
String sProperty = "bytes="+nStartPos+"-"; ~{O@tt)F  
httpConnection.setRequestProperty("RANGE",sProperty); <wt9K2,  
Utility.log(sProperty); W>7o ec  
.hXdXY  
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InputStream input = httpConnection.getInputStream(); ze%)fZI0f  
//logResponseHead(httpConnection); HV6'0_R0  
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byte[] b = new byte[1024]; u
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int nRead; 80ms7 B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) d~J4&w  
{ wms8z  
nStartPos += fileAccessI.write(b,0,nRead); u>-!5=D8  
//if(nThreadID == 1) 'xp&)gL  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q|}Pc>ae  
} Aa/lKiiz  
lN^} qg><  
!=c&U.B  
Utility.log("Thread " + nThreadID + " is over!"); {utIaMb]&v  
bDownOver = true; BK:S:  
//nPos = fileAccessI.write (b,0,nRead); _-I0f##.  
} 3F0:v,+;  
catch(Exception e){e.printStackTrace ();} \TBY)_[ {  
} "&/&v  
} I806I@ix  
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//打印回应的头信息 pYs"Y;%  
public void logResponseHead(HttpURLConnection con) L$+ap~ld  
{ SW%d'1ya  
for(int i=1;;i++) 9WuKW***  
{ vb.`rj6  
String header=con.getHeaderFieldKey(i); _,4f z(  
if(header!=null) =2eG j'}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `cr.C|RT:  
Utility.log(header+" : "+con.getHeaderField(header)); S)*eAON9  
else ^CwzAB  
break; o5FBqt  
} obE_`u l#  
} 93d ht  
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public void splitterStop() n300kp
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{ nNFZ77lg  
bStop = true; tXTa>Q  
} )LwB  
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} JtU/%s  
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/* bg)yliX  
**FileAccess.java 9c1n  
*//文件访问(定位，写) DPNUm<>  
package NetFox; XoaBX2  
import java.io.*; f&Bu_r  
!f\y3p*j  
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public class FileAccessI implements Serializable{ {=><@]N  
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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 *r+i=i8{  
RandomAccessFile oSavedFile; zKWcDbj  
long nPos; |T9p#) ec2  
}IGr%C(3%  
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public FileAccessI() throws IOException x=bAR%i~  
{ dOe|uQXyD  
this("",0); tsZrn  
} $IQ !g  
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public FileAccessI(String sName,long nPos) throws IOException #]|9aVrr  
{ ge[+/$(1  
oSavedFile = new RandomAccessFile(sName,"rw"); S3Tww
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this.nPos = nPos; AtA}OY]D/  
oSavedFile.seek(nPos); CBTa9|57  
} q7wd96G:  
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public synchronized int write(byte[] b,int nStart,int nLen) VWG#v#o  
{ %9=^#e+pE  
int n = -1; Au"[2cG  
try{ ;#!`cgAh  
oSavedFile.write(b,nStart,nLen); lFD$Mc  
n = nLen; ~'HwNzDQc  
} Ajhrsa\~a  
catch(IOException e) gBq,So  
{ 8lt P)K4  
e.printStackTrace (); gRKmfJ*u  
} +MeEy{;  
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return n; G;MgrA#\  
} <vA^%D<\~  
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} l9q ygh  
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v.,C"^W  
/* {JzX`Z30l  
**SiteInfoBean.java 8Hs>+Udl  
*/ yU*j{>%RsK  
package NetFox; lyx p:  
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public class SiteInfoBean { !w98[BE7  
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private String sSiteURL; //Site's URL r 06}@7  
private String sFilePath; //Saved File's Path X1i6CEa<  
private String sFileName; //Saved File's Name :*6tbUp  
private int nSplitter; //Count of Splited Downloading File NwuME/C7#  
~c`@uGw  
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public SiteInfoBean() ."PR Z,  
{//nSplitter的缺省值为5 ;vF8V`f  
//default value of nSplitter is 5 ~|pVz/s|G  
this("","","",5); }O@S;[v S  
} wr8n*Du  
%dS7u$Rnh  
(ZjIwA9>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) JQE^ bcr  
{ .7Ys@;>B  
sSiteURL= sURL; @=b0>^\m  
sFilePath = sPath; As1Er[>  
sFileName = sName; #* 
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this.nSplitter = nSpiltter; )AqM?FE4R  

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3.Qf^p  
} <h U ZD;  
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7J,W#Ql)5  
public String getSSiteURL() }!& w<wR  
{ /^#k/z  
return sSiteURL; E[t\LTt*n  
} CjOaw$s  
B8|=P&L7N  
o]}b#U8S  
public void setSSiteURL(String value) M`KrB5a+6  
{ ()(@Qcc  
sSiteURL = value; C1|e1  
} _1dG!!L_  
fmA&1u/xMs  
,^,Vq]$3  
public String getSFilePath() ^;NM'Z  
{ 1
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return sFilePath; ;MCv  
} dj?.Hc7od  
u-pE ;|  
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public void setSFilePath(String value) C\.?3  
{ ?;|$R   
sFilePath = value; s:R>uGYOd  
} :I F&W=?9  
Nb#E+\q  
t\{q,4  
public String getSFileName() A!<R?  
{ *AGC[w}/  
return sFileName; /zuU  
} '7wI 2D  
L,waQk / @  
^gH.5L0]gH  
public void setSFileName(String value) 7u!R 'D  
{ (bH"x  
sFileName = value; 2j4VW0:  
} X||oiqbY  
{;Mcor3  
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public int getNSplitter() 88pz<$  
{ /Rx%}~x/m  
return nSplitter; cpFw]w%]  
} kdQ=%  
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public void setNSplitter(int nCount) {^"c>'R  
{ }N2T/U  
nSplitter = nCount; nrwb6wj  
} X LA  
} *u 3K8"XZ  
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/* a%;$l_wVT:  
**Utility.java u~1[nH:  
*/ g}$]K!F  
package NetFox; WsJ3zZc  
#R305  

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public class Utility { *FK!^
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Z?XE~6aP>  
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public Utility() $62ospR^Y  
{ V`S6cmwdc\  
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l K}('7\  
} L;fhJ~r  
O#Xq0o  
//线程睡眠 S<88>|&n]  
public static void sleep(int nSecond) /ta-jOcRH&  
{ FFR_1Vf  
try{ K$#(\-M  
Thread.sleep(nSecond); 1xL2f&bG  
} RQ9fA1YP  
catch(Exception e) JT[|l-\zo  
{ '<>pz<c  
e.printStackTrace (); ,U]
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} PM7*@~.  
} HR\yJt  
< I8hy$+6  
//日志 {/XzIOO;b  
public static void log(String sMsg) p!|Wp  
{ >Ah [uM  
System.err.println(sMsg); Eae]s8ek9  
} ysGK5kFz  
asj^K|.z  
-?2ThvT  
public static void log(int sMsg) ~-A5h(  
{ #&1mc_`/  
System.err.println(sMsg); ,D+pGxbr   
} g>/,},jv[x  
} /XS}<!)%  
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jNaK]  
/*
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**TestMethod.java db@i*Bf  
*/ h.sH:]Z  
package NetFox; Pqo"~&Y|~  
c:>&Bg&,6T  
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public class TestMethod { _j}|R(s*+V  
vtCt6M  
vbmi_[,U  
public TestMethod() 9p+DAs{i  
{ ///xx/weblogic60b2_win.exe CbS- Rz:  
try{ D;.-e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); n0>#?ek12  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9y>dDNM\<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); GBHv| GO  
fileFetch.start(); b5No>U) /  
} ;} Ty b  
catch(Exception e){e.printStackTrace ();} Z8z.Xn  
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} ;&s`g   
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public static void main(String[] args) "n}J
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{ )ra_`Qdcf  
new TestMethod(); Q
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} rt_%_f>qd  
} 4~P{H/]  
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