http断点续传简单实现（java)

/* \?5[RR  
**SiteFileFetch.java ,d/CU  
*/ brpN>\  
package NetFox; ]ly)z[is"]  
import java.io.*; rm7*l<v6  
import java.net.*; ijR-?nrR  
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public class SiteFileFetch extends Thread { D9@<#2-  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 'xu7AKpU)  
long[] nStartPos; //开始位置 +ik N) D  
long[] nEndPos; //结束位置 Yp?a=R  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \k$]GK-  
long nFileLength; //文件长度 x r+E  
boolean bFirst = true; //是否第一次取文件 B<|q{D$N/  
boolean bStop = false; //停止标志 9e :d2  
File tmpFile; //文件下载的临时信息 >E2WZHzd2  
DataOutputStream output; //输出到文件的输出流 |?pYJkrYO  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |eVTxeq  
public SiteFileFetch(SiteInfoBean bean) throws IOException /ab K/8ZQ  
{ xr1I8 5kM  
siteInfoBean = bean; $yxIE}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); i >/@]2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); O7L6Htya  
if(tmpFile.exists ()) [3bwbfHhi  
{ <T=o]M$  
bFirst = false; ,_4KyLfBF  
read_nPos(); /fcwz5~  
} .bY1N5=sz  
else _#\5]D~""  
{ Hf E;$  
nStartPos = new long[bean.getNSplitter()]; F0o18k_"  
nEndPos = new long[bean.getNSplitter()]; %CfTqbB  
} GQc%
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} @o-evH;G  
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public void run() rH9|JEz  
{ u>-uRz<)t  
//获得文件长度 ?\ i,JJO  
//分割文件 I[YfF  
//实例FileSplitterFetch ^<H#dkECG  
//启动FileSplitterFetch线程 v+, w{~7RH  
//等待子线程返回 TTjjyZ@  
try{ z8MpE  
if(bFirst) !-Tm
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{ (4/`@;[  
nFileLength = getFileSize(); }N=zn7W  
if(nFileLength == -1) k@X As  
{ sRI=TE]s  
System.err.println("File Length is not known!"); yyYbB]D  
} L``mF(R^  
else if(nFileLength == -2) S&g-  
{ 6(RqR  
System.err.println("File is not access!"); Tlv|To  
} 3_['[}  
else 1F%*k &R  
{ wz2)seZY  
for(int i=0;i<nStartPos.length;i++) ;?[+vf")  
{ ;jfXU_K  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); A
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} o3`gx  
for(int i=0;i<nEndPos.length-1;i++) {hp
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{ KLM^O$=  
nEndPos = nStartPos[i+1]; n@8{FoF  
} v6(l#,  
nEndPos[nEndPos.length-1] = nFileLength; oZ>]8vw  
} &ppZRdq]  
} oA^ ]x>  
l<:)rg^,  
MhXm-<4  
//启动子线程 *v-xC5L1\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; H5rNLfw '  
for(int i=0;i<nStartPos.length;i++) [aVJYr2  
{ z[I/ AORl  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sjbC~Te--  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), q+=@kXs>+  
nStartPos,nEndPos,i); |r!Qhb
.!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e(5Px!B  
fileSplitterFetch.start(); M>l+[U  
} v}t:}M<;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8c'-eT"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2G*#Czr"  
nEndPos = " + nFileLength); oEf^o*5(  
// fileSplitterFetch[nPos.length-1].start(); 7o%|R2mL}  
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//等待子线程结束 <Gt{(is  
//int count = 0; E<[ bgL  
//是否结束while循环 J;9QDrl`  
boolean breakWhile = false; hndRgCo  
23?0'AU  
mAERZ<I  
while(!bStop) 6>^k9cJp  
{ MPw7!G(qj  
write_nPos(); 2n,
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Utility.sleep(500); icbYfgQ  
breakWhile = true; W-B[_  
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for(int i=0;i<nStartPos.length;i++) uw&,pq  
{ +=xRr?F  
if(!fileSplitterFetch.bDownOver) "+Yn;9  
{ =C}<0<"iF  
breakWhile = false; VZ!$'??  
break; tOVm~C,R  
} BFRSYwPr  
} -v2q:x'G#  
if(breakWhile) Q";eyYdOL  
break; +u)$o  
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'Z9F0l"Nr  
//count++; .OUE'5e p  
//if(count>4) a-hGpYJJG  
// siteStop(); -L3RzX  
} ''YjeX  
2C&%UZim;P  
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System.err.println("文件下载结束！"); &g {_.n,  
} cW%O-  
catch(Exception e){e.printStackTrace ();} h0pr"]sO;$  
} jzw?V9Ijb  
.`RC,R`C  
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//获得文件长度 
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public long getFileSize() 
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{ Z}f_\d'  
int nFileLength = -1; ~(S4/d5  
try{ SW,Po>Y  
URL url = new URL(siteInfoBean.getSSiteURL()); TD9`SSpP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hgltD8,  
httpConnection.setRequestProperty("User-Agent","NetFox"); iB-s*b<`~  
7mBL#T2   
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int responseCode=httpConnection.getResponseCode(); EC/R|\d?Un  
if(responseCode>=400) -/?<@*n  
{ &o.SmkJI  
processErrorCode(responseCode); vL0Ol-Vt  
return -2; //-2 represent access is error xx8na8  
} aQFHB!  
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String sHeader; U @|_5[nl  
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for(int i=1;;i++) H
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{ t"fD"Xpj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K(2s%  
//Utility.log(in.readLine());  j C?  
sHeader=httpConnection.getHeaderFieldKey(i); IF1}}[Ht  
if(sHeader!=null) N%+M+zEJ  
{ <ZEA&:p  
if(sHeader.equals("Content-Length")) |zKcL3*  
{ WTx;,TNG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); a$m?if=  
break; Q{60^vg  
} Z%R^;8!~  
} +l(}5(wc  
else `<q5RuU  
break; yk/XfwQ5  
} @T"385>  
} "?SnA +)  
catch(IOException e){e.printStackTrace ();} ";]m]PRAam  
catch(Exception e){e.printStackTrace ();} @$]h[   
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Utility.log(nFileLength); 9 pn1d.  
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return nFileLength; c/RG1w  
} |a+8-@-Tj  
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//保存下载信息（文件指针位置） cf9y0  
private void write_nPos() $.Ni'U  
{ O9Aooe4W=  
try{ <3KrhhH  
output = new DataOutputStream(new FileOutputStream(tmpFile)); G`jhzG  
output.writeInt(nStartPos.length); trLs4o,  
for(int i=0;i<nStartPos.length;i++) vq}V0- <  
{ 4)_ [)MZ\j  
// output.writeLong(nPos); U N/.T   
output.writeLong(fileSplitterFetch.nStartPos); @p;4g_F  
output.writeLong(fileSplitterFetch.nEndPos); 0U'r ia:$  
} F+GQl  
output.close(); UWHC]V?  
} H UjmJu6f{  
catch(IOException e){e.printStackTrace ();} y3#\mBiw  
catch(Exception e){e.printStackTrace ();} {
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} SDkN  
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//读取保存的下载信息（文件指针位置） 0:*$i(2  
private void read_nPos() L@wnzt  
{ dx^3(#B  
try{ +]#>6/2q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T(6S~;,Z  
int nCount = input.readInt(); jVDNThm+  
nStartPos = new long[nCount]; (<12&=WxE  
nEndPos = new long[nCount]; f]Vz!hM~  
for(int i=0;i<nStartPos.length;i++) GCrN:+E0FJ  
{ B?jF1F!9  
nStartPos = input.readLong(); f5N~K>  
nEndPos = input.readLong(); m+gVGK  
} jV(IS
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input.close(); #xmUND`@  
} Xe5J  
catch(IOException e){e.printStackTrace ();} *)`:Nm~y  
catch(Exception e){e.printStackTrace ();} SV.*Z|"^N  
} G 6][@q  
tQ/U'Ap&  
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private void processErrorCode(int nErrorCode) 4AGc2e'u  
{ Uc4r  
System.err.println("Error Code : " + nErrorCode); E_
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} ~Sh}\&3p  
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* 08LW|:,  
//停止文件下载 !%Ak15o  
public void siteStop() :A[ Gtc(_  
{ k=LY 6  
bStop = true; '!_o`t@  
for(int i=0;i<nStartPos.length;i++) (k[<>$hL*  
fileSplitterFetch.splitterStop(); |Oo WGVc  
6)W9/V-W  
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} y"2c; *7[{  
} zI
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//负责部分文件的抓取 s#4 "f  
**FileSplitterFetch.java @gZ%>qe  
*/ pPIH`I
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package NetFox; 6:e0?R^aD"  
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import java.io.*; I!bG7;=_  
import java.net.*; &=f%(,+  
)&*&ZL0  
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public class FileSplitterFetch extends Thread { }+SnY8A=KZ  
Ngg (<ZN  
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String sURL; //File URL j3$KYf`T}  
long nStartPos; //File Snippet Start Position towQoqv  
long nEndPos; //File Snippet End Position >:Rc%ILym  
int nThreadID; //Thread's ID " I:j a7  
boolean bDownOver = false; //Downing is over wt-)5f'{  
boolean bStop = false; //Stop identical ~V(WD;Mk  
FileAccessI fileAccessI = null; //File Access interface T'w=v-(J  
~x824xW  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `TA
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{ +|^rz#X  
this.sURL = sURL; uYV#'%  
this.nStartPos = nStart; S]k<Ixvf  
this.nEndPos = nEnd;  M7hff4c  
nThreadID = id; qF>}"m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :c c#e&BO  
}  ~UXW  
[7$.)}Q-  
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public void run() e5MX5 T^  
{ 1
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while(nStartPos < nEndPos && !bStop) D(yRI  
{ P
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try{ j:rGFd  
URL url = new URL(sURL); fAYm3+.l3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `ez_ {  
httpConnection.setRequestProperty("User-Agent","NetFox"); F $B_;G  
String sProperty = "bytes="+nStartPos+"-"; 5v8_ji#l[  
httpConnection.setRequestProperty("RANGE",sProperty); h%pgdix  
Utility.log(sProperty); @99@do|C  
jeC3}BL}  
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InputStream input = httpConnection.getInputStream(); c_wvuKa  
//logResponseHead(httpConnection); AtU%S9  
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byte[] b = new byte[1024]; ;+C2P@M  
int nRead; $r+_Y/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) x# MMrV&M  
{ 0])D)%B k  
nStartPos += fileAccessI.write(b,0,nRead); c[VVCN8dA  
//if(nThreadID == 1) %
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )<YfLDgTs  
} e7tp4M9!%  
O?,Grn%'.  
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Utility.log("Thread " + nThreadID + " is over!"); Ql>bsr}  
bDownOver = true; iepolO=  
//nPos = fileAccessI.write (b,0,nRead); k4T`{s}e  
} f[1 s4Dp3-  
catch(Exception e){e.printStackTrace ();} cPunMHD  
} !U::kr=t  
} QrBb!.r  
>E
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&6="r}  
//打印回应的头信息 <cm(QNdcC  
public void logResponseHead(HttpURLConnection con) ICdfak  
{ iy!SqC  
for(int i=1;;i++) O,.c gX   
{ fM/~k>wl  
String header=con.getHeaderFieldKey(i); Dc@OrQu  
if(header!=null) 5]f6YlJZ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); L`3;9rO  
Utility.log(header+" : "+con.getHeaderField(header)); <S ae:m4  
else _w}l,   
break; N=T 0Td  
}
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} h-.xx4D  
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public void splitterStop() Llf#g#T  
{ "%I<yUP]U  
bStop = true; >\?RYy,s$  
} lxsn(- j  
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} 8AVtUU  
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/* k3+LP7|*  
**FileAccess.java :y.~IQN  
*//文件访问(定位，写) )TfX}  
package NetFox; Lm8uN?  
import java.io.*; [a_'pAH  
sTS/]"l  
6Vgxfic  
public class FileAccessI implements Serializable{ ^ItL_4  
dOT7;@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;I9g;}  
RandomAccessFile oSavedFile; f"z;'  
long nPos; WES$B7y  
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public FileAccessI() throws IOException [
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{ ]f~!Qk!I7r  
this("",0); gNJdP!(t  
} ]JR2Av  
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[sNvCE$\]  
public FileAccessI(String sName,long nPos) throws IOException K&VMhMVb  
{ Tb:6IC7="  
oSavedFile = new RandomAccessFile(sName,"rw"); I~GHx5Dk  
this.nPos = nPos; LAFxeo  
oSavedFile.seek(nPos); &+0?Xip{Z  
} p9 G{Q  
ix hF,F
 
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public synchronized int write(byte[] b,int nStart,int nLen) )Ma/]eZ^I  
{ mp)+wZAN&  
int n = -1; D*>#]0X  
try{ F`La_]f?b\  
oSavedFile.write(b,nStart,nLen); $V!25jQ  
n = nLen; F9"Xu-g  
}  7p- RPC  
catch(IOException e) S5kD|kJ  
{ .D;6 r4S  
e.printStackTrace (); |/ji
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} )HcLpoEi  
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return n;
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} @?jtB  
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} Yw yMCd  
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/* vN:!{)~z  
**SiteInfoBean.java sjOv!|]A  
*/ FUf.3@}  
package NetFox; ^ir)z@P?V  
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public class SiteInfoBean { _%er,Ed  
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private String sSiteURL; //Site's URL tJ7F.}\;C  
private String sFilePath; //Saved File's Path r \[|'hA  
private String sFileName; //Saved File's Name ;l1.jQh  
private int nSplitter; //Count of Splited Downloading File 1szObhN-l  
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in5e *  
public SiteInfoBean() [Y~~C J  
{//nSplitter的缺省值为5 yZ[=Y  
//default value of nSplitter is 5 0b/@QgJ  
this("","","",5); & Zn`2%  
} SQhVdYU1'  
* nFzfV  
q7<d|s
 
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xticC>  
{ t|V<K^  
sSiteURL= sURL; j!y9E~Zz  
sFilePath = sPath; mE5{)<N:C  
sFileName = sName; ;c>"gW8  
this.nSplitter = nSpiltter; -EE'xh-zD  
E#_2t)20  
M^Y[Y@U
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} kz1#"8Zd!  
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public String getSSiteURL() 'l=>H#}<B  
{ FZO&r60$E  
return sSiteURL; ;HH%OfQq  
} (9oo8&GG  
p"c6d'qe  
qHp2;  
public void setSSiteURL(String value) ]{q=9DczG(  
{ LSA6*Q51  
sSiteURL = value; Q(cLi:)X2  
} FZn1$_Svr  
>Oj$Dn=  
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public String getSFilePath() xs\<!  
{ -3i(N.)<;  
return sFilePath; 1U#W=Fg'  
} !L8q]]'XM  
dqJ 8lU?  
1;1;-4k7I  
public void setSFilePath(String value) 8b.k*,r>  
{ #^r-D[/m  
sFilePath = value; wM4{\  f\  
} <W!nlh  
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public String getSFileName() 3vcyes-U  
{ .:f ao'  
return sFileName; ;l_b.z0^6  
} .`m|Uf#" _  
?g{[U0)  
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public void setSFileName(String value) y>x"/jzF#  
{ =WUL%MfW  
sFileName = value; V\x'w*FP  
} s|H7;.3gp  
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public int getNSplitter() G-2~$ u  
{ [n
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return nSplitter; lY"l6.c  
} w-ald?`  
%;ED}X  
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public void setNSplitter(int nCount) -rI7ihr*  
{ s=-?kcoJ2d  
nSplitter = nCount; y>0 @.  
} gh*k\0  
} L`K)mCr  
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_g/d/{-{Q  
/* fqbeO9x  
**Utility.java }v2p]D5n.  
*/ eA(\#+)X `  
package NetFox; 9&=%shOc+x  
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,"`3N2!Y}  
public class Utility { r9u'+$vmF  
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(*\&xRY|C  
public Utility() hz;SDaBA  
{ A\rY~$Vr  
*!y04'p`<  
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} *vRHF1)L  
lshSRir  
//线程睡眠 v"(6rZsa  
public static void sleep(int nSecond) D[@-`F  
{ *8a[M{-
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try{ y@*4*4
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Thread.sleep(nSecond); A@lM=   
} (AZneK :*  
catch(Exception e) W%ix|R^2]  
{ HI D6h!  
e.printStackTrace (); YK8l#8K  
} b_{+OqI  
} M_E$w$l2<  
@]X!#&2>  
//日志 D&mPYxXL  
public static void log(String sMsg) `{"V(YMEV  
{ [*)2Ou  
System.err.println(sMsg); #oEtLb@O  
} ZUB]qzmK  
502(CO>  
Z%.Ld2Q{  
public static void log(int sMsg) 78xiT  
{ %iIr %P?  
System.err.println(sMsg); X%*BiI  
} 9} C(M?d  
} J^` pE^S  
Gv)*[7  
E]a,2{&8<  
/* "0G)S'  
**TestMethod.java Sb?v5  
*/ O&.gc p!  
package NetFox; PB8U+  
0""%@X]m  
;2BPEo>z9  
public class TestMethod { 65&+Fv  
P1TTaYu  
{2g?+8L$Z  
public TestMethod() q}JP;p(#  
{ ///xx/weblogic60b2_win.exe Gqar5  
try{ |9CPT%A#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =x^IBLHN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); R<h:>.M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %I)*5M6  
fileFetch.start(); S
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} ]Ah<kq2sk  
catch(Exception e){e.printStackTrace ();} SV2\vby}C  
"\afIYS I  
k lr1"q7  
} { zalB" i  
A:sP%c;  
1G,'  
public static void main(String[] args) 4NFvX4  
{ c&L|e$C]  
new TestMethod(); ;x{J45^  
} .ddf'$6h  
} .YS48 c  
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