http断点续传简单实现（java)

/* jw2hB[WR  
**SiteFileFetch.java p_g8d&]V  
*/ fk5pPm|MiL  
package NetFox; 0[Zs8oRiI  
import java.io.*; "\afIYS I  
import java.net.*; J(,gLl  
}`$({\^w  
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public class SiteFileFetch extends Thread { z*^vdi0  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Q?m= a0g  
long[] nStartPos; //开始位置 ap|V}jC  
long[] nEndPos; //结束位置 [ dVRVm0N  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]CnT4[f!  
long nFileLength; //文件长度 .a]av  
boolean bFirst = true; //是否第一次取文件 J]*?_>"#8  
boolean bStop = false; //停止标志 ]'i}}/}u2  
File tmpFile; //文件下载的临时信息 QN~9O^  
DataOutputStream output; //输出到文件的输出流 -S$Y0FDV  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） pEGHW;  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^zS|O]Tx  
{ ~ln96*)M;  
siteInfoBean = bean; P.t7_v>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >RmL0d#B  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); c$%I^f}'  
if(tmpFile.exists ()) 6k\8ulHw  
{ 7LW%:0  
bFirst = false; $xj>j  
read_nPos(); euh rEjwkH  
} \"=@uqar2  
else K&vqk/JW1  
{ V@ph.)z  
nStartPos = new long[bean.getNSplitter()]; =G/`r!r*0I  
nEndPos = new long[bean.getNSplitter()]; \]t}N  
} n<7R6)j6  
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}  A,|lDsvM  
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public void run() EtvYIfemr  
{ ^pa -2Ao6  
//获得文件长度 Nj4^G ~_  
//分割文件 PHn3f;I  
//实例FileSplitterFetch o{ \r1<D  
//启动FileSplitterFetch线程 AqP7UL  
//等待子线程返回 XbAoW\D(  
try{ <NX6m|DD  
if(bFirst) M$GZK'%  
{ Jp`qE  
nFileLength = getFileSize(); <Okl.Iz>  
if(nFileLength == -1) ji|tc9#6  
{ -u'BK@;
  
System.err.println("File Length is not known!"); V IU4QEW`x  
} )eSD5hOI)  
else if(nFileLength == -2) .3T#:Hl  
{ 1:iT#~n  
System.err.println("File is not access!"); ?`D/#P  
} Y]t)k9|vv  
else V\o&{7!  
{ 0j|JyS:}G  
for(int i=0;i<nStartPos.length;i++) w!^{Q'/,Q  
{ PP)-g0^@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); W[tX%B  
} 5PCKBevV  
for(int i=0;i<nEndPos.length-1;i++) +q3E>K9a  
{ _"%-=^_  
nEndPos = nStartPos[i+1]; `~3y[j]kO  
} rwou[QU  
nEndPos[nEndPos.length-1] = nFileLength; APucA  
} yY42+%P  
} |nj,]pA  
b6UD!tXp  
jPNm $Y1  
//启动子线程 1 9C=' TMS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VM[Vhk[  
for(int i=0;i<nStartPos.length;i++) %CiZ>`5n#  
{ rYMHc@a9(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +gOv5Eno-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [8Zvs=1  
nStartPos,nEndPos,i); f"G?#dW/1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aC2\C=ru_  
fileSplitterFetch.start(); N-Nq*  
} VZArdXTP  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -F|
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S>pbplE  
nEndPos = " + nFileLength); ]RJcY1  
// fileSplitterFetch[nPos.length-1].start(); m0k~8^L@f  
XZFM|=%X  
_7"G&nZ0  
//等待子线程结束 Pb^Mc <j  
//int count = 0; ("L&iu\`@  
//是否结束while循环 &qP&=( $  
boolean breakWhile = false; u;qBW uO  
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while(!bStop) U&\8~h  
{ !h0#es\  
write_nPos(); HsG
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Utility.sleep(500); fc#zhp5bX  
breakWhile = true; .:b|imgiv  
2%Y]M%P  
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for(int i=0;i<nStartPos.length;i++) 5 5_#?vw  
{ }t[?g)"M#-  
if(!fileSplitterFetch.bDownOver) (0T6kD  
{ VY5/C;0^h  
breakWhile = false; KPOr8=Rc  
break; p=65L  
}  !Z'x h +  
} |h; _r&  
if(breakWhile) dt(#|8i%  
break; Rx22W:S=C.  

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{\Eqo4A5}  
//count++; bI,gNVN=  
//if(count>4) B9RB/vHH  
// siteStop(); -&u2C}4s  
} OXs-gC{b  
7aJLC!  
!kl9X-IiI  
System.err.println("文件下载结束！"); I'h6!N"  
} Fx.hti  
catch(Exception e){e.printStackTrace ();} pk*cch#  
} ]iyJ>fC  
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=W6AUN/%p  
//获得文件长度 vPn(~d_  
public long getFileSize() tf?u ;n  
{ X/_e#H0  
int nFileLength = -1; yE(>R(^  
try{ a+TlZE>8  
URL url = new URL(siteInfoBean.getSSiteURL()); q89#Ftkt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ztNm,1pnQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); `43`*=  
 Sxrbhnx  
4,!S?:7  
int responseCode=httpConnection.getResponseCode(); )pS1yYLj  
if(responseCode>=400) 4|ryt4B  
{ =#AeOqs( q  
processErrorCode(responseCode); cvR|qHNX  
return -2; //-2 represent access is error P| o_/BS  
} G
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String sHeader; pv.
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for(int i=1;;i++) V=pg9KR!T  
{ %C_RBd  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6OJ`R.DM`  
//Utility.log(in.readLine()); xr uQ=Q  
sHeader=httpConnection.getHeaderFieldKey(i); tK3.HvD  
if(sHeader!=null) D6trqB  
{ {%(_Z`vI  
if(sHeader.equals("Content-Length")) M+X>!Os  
{ `c^ _5:euX  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); P#/k5]g  
break; ]o<'T.x  
} :*aBiX"  
} FqOV/B /z2  
else OAu?F}O  
break; _7(>0GY  
} aHosu=NK  
} TbqED\5@9w  
catch(IOException e){e.printStackTrace ();} bDa(@QJ-  
catch(Exception e){e.printStackTrace ();} #{
)=%5=c  
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Utility.log(nFileLength); 8Yr_$5R  
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return nFileLength; ?lJm}0>  
} - Dm/7Sxd`  
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S3V3<4CB  
//保存下载信息（文件指针位置） w /$4 Rv+S  
private void write_nPos() p/|]])2  
{ uFDJRQJ<  
try{ %oasIiO  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'u }|~u
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output.writeInt(nStartPos.length); SomA`y+ERn  
for(int i=0;i<nStartPos.length;i++) F V8K_xj  
{ M),i4a?2  
// output.writeLong(nPos); \IL/?J 5d  
output.writeLong(fileSplitterFetch.nStartPos); a"^0;a  
output.writeLong(fileSplitterFetch.nEndPos); */iD68r|-  
} ^EGe%Fq*x]  
output.close(); P9~7GFas|  
} =W(mZ#*vdY  
catch(IOException e){e.printStackTrace ();} bce>DLF  
catch(Exception e){e.printStackTrace ();} $;1#gq%  
} %./vh=5)  
H]V@Q~?e  
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//读取保存的下载信息（文件指针位置） ?{W@TY@S  
private void read_nPos() H#IJ&w|  
{ xc.(-g[  
try{ .CI {g2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0xbx2jlkY  
int nCount = input.readInt(); L~_3BX  
nStartPos = new long[nCount]; gP
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nEndPos = new long[nCount]; %xtTh]s  
for(int i=0;i<nStartPos.length;i++) a?bSMt}  
{ 9AL
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nStartPos = input.readLong(); $2Y'[Dto\  
nEndPos = input.readLong(); ^z#'o  
} 413,O~^  
input.close(); V!#+Ti/w4  
} )UA$."~O  
catch(IOException e){e.printStackTrace ();} :<ye:P1s  
catch(Exception e){e.printStackTrace ();} %|L+~=  
} m6J7)Wp  
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private void processErrorCode(int nErrorCode) 5z8CUDt 0  
{ n?vw|'(}  
System.err.println("Error Code : " + nErrorCode); '_& Xemz  
} q<mDs$^K  
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~1xln?Q  
//停止文件下载 Wk$ 7<gkr  
public void siteStop() !Z978Aub3&  
{ >e y.7YG  
bStop = true; tu}AJ  
for(int i=0;i<nStartPos.length;i++) uMl.}t2uYu  
fileSplitterFetch.splitterStop(); gBQK  
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} =h,6/cs  
} +]^6&MqO  
//负责部分文件的抓取 Pt~mpRlH
 
**FileSplitterFetch.java R7: >'*F  
*/ f/t1@d!  
package NetFox; 2P9gS[Ub  
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import java.io.*; c,a+u  
import java.net.*; l:v:f@M&
 
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public class FileSplitterFetch extends Thread { {2<A\nW  
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String sURL; //File URL f`w$KVZ1!w  
long nStartPos; //File Snippet Start Position EgO=7?(pW  
long nEndPos; //File Snippet End Position Hn"xn79nc  
int nThreadID; //Thread's ID b0 ))->&2  
boolean bDownOver = false; //Downing is over ))"J  
boolean bStop = false; //Stop identical s[h& Uv"G  
FileAccessI fileAccessI = null; //File Access interface 23XSQHVx  
d#yb($HAJ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 44T>Yp09  
{ 8x$BbK  
this.sURL = sURL; \ FW{&X9a  
this.nStartPos = nStart; 0{bGVLp  
this.nEndPos = nEnd; s)B
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nThreadID = id; '`g#Zo  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 xBH`=e<  
} =ML6"jr  
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public void run() 4naL2 Y!  
{ (
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while(nStartPos < nEndPos && !bStop) B
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{ z(]14250  
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try{ 
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URL url = new URL(sURL); TCAtb('D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =Q985)Y&  
httpConnection.setRequestProperty("User-Agent","NetFox"); U X)k;h  
String sProperty = "bytes="+nStartPos+"-"; %_xRS  
httpConnection.setRequestProperty("RANGE",sProperty); n(^{s5 Rr  
Utility.log(sProperty); :G$f)NMK  
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InputStream input = httpConnection.getInputStream();
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//logResponseHead(httpConnection); KKm&~^c  
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byte[] b = new byte[1024]; m89-rR:Kc  
int nRead; P/;sZo  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :
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{ [<m1xr4"k  
nStartPos += fileAccessI.write(b,0,nRead); 7{HJjH!zx  
//if(nThreadID == 1) y
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q]WjW'Ry\  
} g{K*EL<  
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Utility.log("Thread " + nThreadID + " is over!"); J#DYZ>}Y  
bDownOver = true; Zcq'u jU  
//nPos = fileAccessI.write (b,0,nRead); 7PG&G5  
} 
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catch(Exception e){e.printStackTrace ();} b4`t, D  
} Ara D_D  
} le%&r  
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//打印回应的头信息 ~"eos~AuW  
public void logResponseHead(HttpURLConnection con) ZMO7o 1"  
{ G+Ft2/+\  
for(int i=1;;i++) A:$Qt%c  
{ 5Ug.J{d  
String header=con.getHeaderFieldKey(i); 5~&9/ALk5  
if(header!=null) X yi[z tN  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); JvFd2@  
Utility.log(header+" : "+con.getHeaderField(header)); LQT^1|nq  
else X
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break; @~pIyy\_  
} >Micc   
} QkbXm[K.Z  
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public void splitterStop() 0k"n;:KM8  
{ ?@"F\Bv<h  
bStop = true; jd<`W  
} !1 :%!7  
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} Db"jzMW.  
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/* IC&>PwXb  
**FileAccess.java (>O'^W\3p  
*//文件访问(定位，写) P|,@En 1!  
package NetFox; 'Fi\Qk'D@  
import java.io.*; jWHv9XtW  
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public class FileAccessI implements Serializable{ f' |JLhs  
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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 lYz{#UX}  
RandomAccessFile oSavedFile; m2wGg/F5  
long nPos; _P6e%O8C#  
3[mVPV  
W&E?#=*X  
public FileAccessI() throws IOException bCWSh~  
{ -'SpSy'_  
this("",0); OV<'v%_&  
} qffVF|7  
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public FileAccessI(String sName,long nPos) throws IOException "+SnHpNx  
{ [D/q  
oSavedFile = new RandomAccessFile(sName,"rw"); `M0m`Up  
this.nPos = nPos; ?` ?HqR0  
oSavedFile.seek(nPos); H@
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} |~)!8N.{  
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public synchronized int write(byte[] b,int nStart,int nLen) ]w7wwU^^*U  
{ R@ksYC3 F  
int n = -1; l/WQqT  
try{ u7Z-kZ
  
oSavedFile.write(b,nStart,nLen); ^FO&GM2a  
n = nLen; Er@'X0n  
} b;kgP`%%  
catch(IOException e)
?@n, 9!  
{ =3K}]3f  
e.printStackTrace (); ScN'|Ia.-  
} &lnr?y^  
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return n; rQE:rVKVh  
} B=vBJC)  
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}  ,2yIKPWk  
](%EQ[  
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/* P_(QG 6  
**SiteInfoBean.java },r9f MJ  
*/ _x+)Tv  
package NetFox; ;ZOu-
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'YFy6rds  
public class SiteInfoBean { +!"GYPUXy  
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private String sSiteURL; //Site's URL 0Y|"Bo9
k  
private String sFilePath; //Saved File's Path tfz"9PV80  
private String sFileName; //Saved File's Name mz-sazgV  
private int nSplitter; //Count of Splited Downloading File _
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$"
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public SiteInfoBean() 5t
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{//nSplitter的缺省值为5 msf%i!  
//default value of nSplitter is 5 t%S2D  
this("","","",5); 7XM:4whw  
} ;W~H|M  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2!
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{ 1n3XB+*  
sSiteURL= sURL; ?^} z  
sFilePath = sPath; ^*g= 65!1  
sFileName = sName; @zs.M-F  
this.nSplitter = nSpiltter; IjaFNZZC!  
|BA&ixHe~C  
5MX7V4ist  
} 3*8m!gq7s  
\&XtPQ  
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public String getSSiteURL() _keI0ML-#  
{ 8x~'fzf;Sq  
return sSiteURL; .]XBJc  
} 0bz':M#k &  
>~}}*yp  
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public void setSSiteURL(String value) SJ7-lben3  
{ +,q#'wSQG  
sSiteURL = value; ~rfUqM]I   
} ]broU%#"  
F2)\%HR  
|U:VkiKt  
public String getSFilePath() { POfT m}  
{ Tebu?bj  
return sFilePath; `ElJL{Rn  
} ,DIr&5>p2  
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public void setSFilePath(String value) +*`>7m<^  
{ M+l~^E0Wj  
sFilePath = value; P[K42mm  
} -IE=?23Do?  
"2_nN]%u-  
%|(Cb!ySX  
public String getSFileName() =38
c}(  
{ p!/ *(TT  
return sFileName; .
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} Nm{J=`  
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:"Gd;~p.  
public void setSFileName(String value) Sp-M:,H3H  
{ Yu+;vjbK-  
sFileName = value; [M#I Nm}  
} *|B5,Ey  
gR76g4|=;  
u OB`A-K  
public int getNSplitter() W<\*5oB%H  
{ X,`^z,M%I  
return nSplitter; mV;)V8'  
} gg?O0W{  
LZ4Z]!V  

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public void setNSplitter(int nCount) vSv:!5*  
{ f>[!Zi*  
nSplitter = nCount; '>Uip+'  
} 0?w
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}  K)P].htw  
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W61nJ7@  
/* zwgO|Qg;  
**Utility.java -(VX+XHW  
*/ yP"D~u  
package NetFox; 1Gp|_8  
5e >qBw8t  
1#V&'A  
public class Utility { oV;I8;#\J  
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public Utility() '/GZ/$a_l  
{ 0czEA  
BDcA_=^R&  
+i(;@
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} +kM*BCPYE  
OE(!^"5?[  
//线程睡眠 8z`Ne(h;  
public static void sleep(int nSecond) df8aM<&m3  
{ vq8&IL  
try{ X8~gLdv8  
Thread.sleep(nSecond); I,7n-G_'  
} oL
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catch(Exception e) FQBAt0  
{ ~+&Z4CYb  
e.printStackTrace (); n_S)9C'=  
} pP*`b<|  
} %0lJ(hm  
yL"pzD`[H  
//日志 9V?:!%J  
public static void log(String sMsg) JU!vVA_  
{ r!)jxIL\  
System.err.println(sMsg); V~4yS4  
} *GC9o/  
.ZVo0  
sSsRn*LN-:  
public static void log(int sMsg) E-b3#\^:  
{ &-(p~[|  
System.err.println(sMsg); 9UcSQ"D  
} #TD0)C/  
} Pi'[d7o  
Sz0CP1WB  
(I ~r~5^  
/* u= ydX  
**TestMethod.java Wu U_RE  
*/ ='vkd=`Si  
package NetFox; P7y.:%DGD0  
,H:{twc   
9Fh1rZD<  
public class TestMethod { |YK4V(5x  
!--A"  
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public TestMethod() "dFuQB  
{ ///xx/weblogic60b2_win.exe ]7 2wv#-  
try{ a{! 8T  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); RrRE$g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )"H r3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }NF7"tOL  
fileFetch.start(); $
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} Pskg68W  
catch(Exception e){e.printStackTrace ();} H<C+rAIb  
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'/Ag3R  
} ~/1
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Fa9gr/.F,@  
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public static void main(String[] args) {+x;J4  
{ tjt#2i8/  
new TestMethod(); {aYCrk1  
} /+{1;}AT  
} O>Ao#_*hOb  
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