http断点续传简单实现（java)

/* %^GfS@t  
**SiteFileFetch.java NzOx0WLF  
*/ =BAW[%1b  
package NetFox; ryUQU^v  
import java.io.*; ,,Q O^j]4~  
import java.net.*; 3/e.38m|  
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public class SiteFileFetch extends Thread { CiLg]va
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean q"sed]  
long[] nStartPos; //开始位置 -g Sa_8R  
long[] nEndPos; //结束位置 >kDQkhZ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 dkBIx$t  
long nFileLength; //文件长度 4,gK[ dc  
boolean bFirst = true; //是否第一次取文件 H-*yh!  
boolean bStop = false; //停止标志 [KaAXv .X  
File tmpFile; //文件下载的临时信息 V0.vQ/  
DataOutputStream output; //输出到文件的输出流 rt~d6|6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1 A !bE  
public SiteFileFetch(SiteInfoBean bean) throws IOException JZ*/,|1}EC  
{ @oY~..d`
 
siteInfoBean = bean; m6&~HfwN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %wvdn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); u4F5h PO]  
if(tmpFile.exists ()) lC("y' ::  
{ )j(7]uX`  
bFirst = false; 7#ibN!  
read_nPos(); 5Y'qaIFR  
} (%e.:W${  
else }`QUHIF  
{ #Z`q+@@]A  
nStartPos = new long[bean.getNSplitter()]; %x{kc3PnO  
nEndPos = new long[bean.getNSplitter()]; w/S%YW3*  
} ," Wr"  
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} !&ayYu##{  
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public void run() C]eSizS.  
{ ;R5`"`  
//获得文件长度
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//分割文件 W*4-.*U8a  
//实例FileSplitterFetch +xSHL|:b  
//启动FileSplitterFetch线程 o]` *M|  
//等待子线程返回 uK#4(eY=W  
try{ *1 ]uH e  
if(bFirst) 3yY}04[9<  
{ $L>@Ed<  
nFileLength = getFileSize(); ?(y*nD[a  
if(nFileLength == -1) HU}7zK2  
{ m
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System.err.println("File Length is not known!"); #`iB`|  
} k\YG^I  
else if(nFileLength == -2) 5C*Pd Wpl  
{ ;%5N%
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System.err.println("File is not access!"); u\x}8pn  
} V>%rv'G8  
else Ar|0b}=)>  
{ /y#f3r+*2  
for(int i=0;i<nStartPos.length;i++) bv9]\qC]T<  
{  $s c  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r CHl?J  
} BB$>h}  
for(int i=0;i<nEndPos.length-1;i++) %lx!.G  
{ ZW8vza  
nEndPos = nStartPos[i+1]; v ~?qz5:K~  
} 7qLpZ/  
nEndPos[nEndPos.length-1] = nFileLength; {G0T$,'DR  
} E`0?  
} <8i//HOE  
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n;Q7X>-f8`  
//启动子线程 A5RN5`}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]G=L=D^cK  
for(int i=0;i<nStartPos.length;i++) W$;,CU.v  
{ J+DDh=%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V`d,qn)i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Bz-c$me1  
nStartPos,nEndPos,i); S_4?K)n #  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (sTpmQx,b  
fileSplitterFetch.start(); Y>T-af49  
} $}q23  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4Zddw0|2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q&ptc>{bH6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", T_ <@..C  
nEndPos = " + nFileLength); d-ZJL6-  
// fileSplitterFetch[nPos.length-1].start(); @|m/djN5x  
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//等待子线程结束 $q{!5-e  
//int count = 0; .x.]`b(  
//是否结束while循环 ")5":V~fN  
boolean breakWhile = false; syj0.JD  
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while(!bStop)  6f>{"'  
{ 9Cp-qA%t  
write_nPos(); )5JFfp)#  
Utility.sleep(500); |?xN\O^#}  
breakWhile = true; t%FwXaO#  
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for(int i=0;i<nStartPos.length;i++) "5!oi]@>(  
{ 9c'xHO`  
if(!fileSplitterFetch.bDownOver) E\EsWb  
{ v`x.)S1  
breakWhile = false; 2r4Uh1D~  
break; A#<?4&  
} |O+H[;TB6  
} F4z{LhZ  
if(breakWhile) 6ex/TySM  
break; /NFj(+&g+  
(@VMH !3  
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//count++; 0<@KG8@hI;  
//if(count>4) <w9JRpFY  
// siteStop(); EGS)b  
} E_wCN&`[  
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System.err.println("文件下载结束！"); KC6.Fr{  
}
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catch(Exception e){e.printStackTrace ();}  `25yE/  
} 69Ne
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//获得文件长度
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public long getFileSize() 7U"g3a)=  
{ itP,\k7>d  
int nFileLength = -1; =BAr .m+"  
try{ _8J.fT$${  
URL url = new URL(siteInfoBean.getSSiteURL()); sb*G!8j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !;{7-
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httpConnection.setRequestProperty("User-Agent","NetFox"); ]p GL`ge5  
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int responseCode=httpConnection.getResponseCode(); ie95rZp  
if(responseCode>=400) iHf$  
{ &h)yro  
processErrorCode(responseCode); SHgN~Um  
return -2; //-2 represent access is error ..5CC;B  
} +GN(Ug'R  
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String sHeader; 1n8/r}q'H  
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for(int i=1;;i++) xm~`7~nFR  
{ _D&598xx  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |SSSH  
//Utility.log(in.readLine()); : *#-%0  
sHeader=httpConnection.getHeaderFieldKey(i); o5PO=AN  
if(sHeader!=null) 9Q.Yl&A  
{ vn8aFA  
if(sHeader.equals("Content-Length")) my1@41 H  
{ )dw'BNz5hT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *:7rdzn  
break; }R2u@%n{  
} J]'zIOQ  
} ^uc=f2=>,  
else {}n^cq  
break; iWkWR"ysy  
} |YWD8 +  
} C.-,^+t;g  
catch(IOException e){e.printStackTrace ();} [|$h*YK  
catch(Exception e){e.printStackTrace ();} {S)6;|ua'  
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Utility.log(nFileLength); YkSl^j[DHs  
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return nFileLength; nR~@#P\  
} T?
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//保存下载信息（文件指针位置） F/{!tx  
private void write_nPos() T'9'G M  
{ Sz`,X0a  
try{ t3_O H^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ;[DU%f  
output.writeInt(nStartPos.length); zC!t;*8a  
for(int i=0;i<nStartPos.length;i++) `U_)98  
{ 9cF[seE"0  
// output.writeLong(nPos); F)QDJE0  
output.writeLong(fileSplitterFetch.nStartPos); IEi^kJflU  
output.writeLong(fileSplitterFetch.nEndPos); lUZ+YD4  
} .`eN8Dl1  
output.close(); h[Y1?ln&h  
} K\r8g=U  
catch(IOException e){e.printStackTrace ();} bAqA1y3=  
catch(Exception e){e.printStackTrace ();} .L~AL|2_  
} 2%m BK  
2/^3WY1U  
</zEg3F\  
//读取保存的下载信息（文件指针位置） C,r;VyW6BI  
private void read_nPos() <%eG:n,#  
{ 
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try{ (L&d!$,Dv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); [z{1*Xc  
int nCount = input.readInt(); {!L~@r  
nStartPos = new long[nCount]; 9Y9GwL]T  
nEndPos = new long[nCount]; Lqa4Vi  
for(int i=0;i<nStartPos.length;i++) #;yZ  
{ ^yp
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nStartPos = input.readLong();
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nEndPos = input.readLong(); Ti5-6%~&  
} r,p%U!S<hV  
input.close(); ZY+qA  
} ;A*]l'[-  
catch(IOException e){e.printStackTrace ();} oMa6(3T?E  
catch(Exception e){e.printStackTrace ();} XRi8Gpg  
} m:2^=l4  
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private void processErrorCode(int nErrorCode) 7?_CcRe  
{ L="}ErmK  
System.err.println("Error Code : " + nErrorCode); W|mo5qrLS2  
} m-, x<bM?
 
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//停止文件下载 /U9"wvg  
public void siteStop() f]CXu3w(J  
{ h:|qC`}  
bStop = true; wmLs/:~  
for(int i=0;i<nStartPos.length;i++) VI86KJu  
fileSplitterFetch.splitterStop(); +mn[5Y}:  

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} NBGH_6DROw  
} e\L8oOk#r  
//负责部分文件的抓取 YOO+R{4(  
**FileSplitterFetch.java ?e 4/p  
*/ 5\nAeP  
package NetFox; \4fQMG  
.Q2V}D85  
3!]rmZ-W  
import java.io.*; > ~O.@|  
import java.net.*; Gd85kY@w7  
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public class FileSplitterFetch extends Thread { |+9&rAg  
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String sURL; //File URL OneY_<*a<  
long nStartPos; //File Snippet Start Position SmO~,2=  
long nEndPos; //File Snippet End Position K
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int nThreadID; //Thread's ID WpvhTX  
boolean bDownOver = false; //Downing is over 3JR+O<3D  
boolean bStop = false; //Stop identical S f# R0SA  
FileAccessI fileAccessI = null; //File Access interface 9->if/r,o  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Mo|2}nf  
{ (E1~H0^  
this.sURL = sURL; $I?"lky  
this.nStartPos = nStart; dR]m8mdqc1  
this.nEndPos = nEnd; pQB."[n  
nThreadID = id; h<QY5=SF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 V0mn4sfs  
} ]`WJOx4  
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public void run() 5z)~\;[ -  
{ }Q+|W=2t  
while(nStartPos < nEndPos && !bStop) N;%6:I./  
{ f$QNg0v  
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try{ om>KU$g  
URL url = new URL(sURL); Ow,b^|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *oix6  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]Hv[IodJ  
String sProperty = "bytes="+nStartPos+"-"; #/37V2E  
httpConnection.setRequestProperty("RANGE",sProperty);
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Utility.log(sProperty); F!K>Kz  
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InputStream input = httpConnection.getInputStream(); Vxt+]5X  
//logResponseHead(httpConnection); BZ^}J!Q'*  
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byte[] b = new byte[1024]; 4
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int nRead; tZo} ;|~'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u ^RxD^=L  
{ BY*8ri^u  
nStartPos += fileAccessI.write(b,0,nRead); #g!.T g'  
//if(nThreadID == 1) 2 yz _  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _q^E,P  
} hi[pVk~B)  
5!9zI+S|=`  
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Utility.log("Thread " + nThreadID + " is over!"); ],].zlN  
bDownOver = true; EoDA]6?Lj  
//nPos = fileAccessI.write (b,0,nRead); %&bY]w  
} ,hmL/K0"(5  
catch(Exception e){e.printStackTrace ();} &)<)^.@3G^  
} sDV Q#}a  
} Cgc\ ah  
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7 X4LJf  
//打印回应的头信息 2:ylv<\$  
public void logResponseHead(HttpURLConnection con) \73ch  
{ 32 =z)]FZ  
for(int i=1;;i++)  9gZ$
 
{ `r_/Wt{g  
String header=con.getHeaderFieldKey(i); |EN
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if(header!=null) Xn ;AZu^'R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >(RkZ}z  
Utility.log(header+" : "+con.getHeaderField(header)); jc9y<{~x/  
else +ck}l2&#  
break; .N(p=9  
} bZV
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} Y<8vw d  
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public void splitterStop() :M5l*sIO2  
{ {(}By/_  
bStop = true; Y <qm{e  
} 5kXYeP3:  
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} Af{"pzY  
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/* v.5+7,4  
**FileAccess.java )dSi/  
*//文件访问(定位，写) 4X|zmr:A  
package NetFox; SX-iAS[<  
import java.io.*; ~PNub E  
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public class FileAccessI implements Serializable{ RpYERAgT  
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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 )\^-2[;  
RandomAccessFile oSavedFile; $,'*f?d  
long nPos; \uMLY<]P  
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public FileAccessI() throws IOException t&DEb_"De  
{ Ti&z1_u  
this("",0); Z EO WO  
} iG?[<1~  
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public FileAccessI(String sName,long nPos) throws IOException tklH@'q  
{ ^zgo#J5O  
oSavedFile = new RandomAccessFile(sName,"rw"); /H+a0`/  
this.nPos = nPos; 7v_8_K  
oSavedFile.seek(nPos); M& CqSd  
} 4ss4kp_>  
n{SJ_S#a.a  
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public synchronized int write(byte[] b,int nStart,int nLen) 5E_YEBO/  
{ 2dgd~   
int n = -1; =E{`^IT'R  
try{ k-""_WJ~^  
oSavedFile.write(b,nStart,nLen); 7j)8Djzp|  
n = nLen; W`*r>`krVJ  
} /5AJ.r  
catch(IOException e) r!{Up7uL  
{ FU<Jp3<%  
e.printStackTrace (); 7vj2 `+r.  
} dGTsc/$  
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return n; FNId;  
} K'I#W lg  
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} uA#;G/$  
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k.15CA`  
/* #yvGK:F  
**SiteInfoBean.java eQvg7aO;  
*/ _n\GNUA  
package NetFox; 5QO9Q]I#_\  
~.lPEA %%  
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public class SiteInfoBean { Q.c\/&  
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@!d{bQd,  
private String sSiteURL; //Site's URL *G9V'9  
private String sFilePath; //Saved File's Path efE.&]  
private String sFileName; //Saved File's Name 9k[9P;"F:  
private int nSplitter; //Count of Splited Downloading File 8q
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public SiteInfoBean() `x%>8/  
{//nSplitter的缺省值为5 "Os_vlapHo  
//default value of nSplitter is 5 p
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this("","","",5); Xm2z}X(%  
} S?BG_J6A7  
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1 I",L&S1  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {P#|zp4C{  
{ U\!X,a*ts{  
sSiteURL= sURL; CQDkFQq-dq  
sFilePath = sPath; 1hNq8*|  
sFileName = sName; *bpD`s @  
this.nSplitter = nSpiltter; 6/dI6C!  
=rX>1  
IRqy%@)  
} 9490o:s  
)TM4R)r%)9  
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public String getSSiteURL() zT?D<XW>1  
{ DrK{}uM  
return sSiteURL; y Fq&8 x<X  
} =[jXe  
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public void setSSiteURL(String value) I4?5K@a  
{ ! #2{hQRu  
sSiteURL = value; ayF\nk4b  
} t}/( b/VD  
2P{Gxz<#  
[Cv/{f3]u{  
public String getSFilePath() I?G:p+  
{ YQA,f#  
return sFilePath; Q#[9|A9  
} W-lN>]5}m  
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public void setSFilePath(String value) c6]D-YNFG  
{ hpL;bM'  
sFilePath = value; ZLAy- 9^Y  
} R@k&SlL'`  
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public String getSFileName() i@M[>~  
{ Al
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return sFileName; %z4Nl$\  
} c=.(!qdH  
l0A&9g*l2  
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public void setSFileName(String value) p0<\G  
{ <B8!.|19  
sFileName = value; 0b(N^$js'  
} fkNbS  
e'D&
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public int getNSplitter() bhlG,NTP  
{ vTw>JNVI  
return nSplitter; GYUn6P  
} p,i[W.dy.'  
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public void setNSplitter(int nCount) "o}+Ciul  
{
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nSplitter = nCount; Aj+F |l  
} 
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}  t[ C/  
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/* 3HY9\'t6  
**Utility.java O55 xS+3^k  
*/ !5uGd`^I  
package NetFox; cJ @Wt>YI  
t"/q]G5  
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public class Utility { #';:2Nyq  
K?$^@
N  
**G9H  
public Utility() {8,J@9NU  
{ Y#$%iF  
B%+T2=&$7  
+@iA;
2&  
} ]^K4i)\  
>%8KK|V{  
//线程睡眠 )+t0:GwP`:  
public static void sleep(int nSecond) H-fX(9  
{ _Qi&J.U>  
try{ *>qp:;,DKP  
Thread.sleep(nSecond); H@8sNV/u  
} gn".u!9j  
catch(Exception e) L"Olwwmk  
{ 8k1Dj1@0z  
e.printStackTrace (); mk+B9?;cF-  
} 2{G:=U  
} b |p)9&^r  
s 15oN  
//日志 o.\F.C$  
public static void log(String sMsg) N `F~n%N  
{  LsS  
System.err.println(sMsg); R2]Z kg  
} k%QpegN  
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public static void log(int sMsg)
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{ h/hmlnOQl  
System.err.println(sMsg); [>5-$YOT  
} d;9FB[MmOJ  
} ls:w8&`*  
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/* o:P}Wg/NK  
**TestMethod.java .rqhi  
*/ @>>~CZ`l  
package NetFox; bsA-2*Q+  
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public class TestMethod { } .y 1;.  
9b"=9y,  
9=h'9Wo  
public TestMethod() ^)*-Bo)I  
{ ///xx/weblogic60b2_win.exe  ^J)mH[  
try{ =\wxsL  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >!bJslWA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \k!{uRy'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !SdSE^lz`  
fileFetch.start(); E+g@M8D  
} E3gh?6  
catch(Exception e){e.printStackTrace ();} NmJWU:W_@  
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} WE.{p>  
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public static void main(String[] args) H0`]V6+<f  
{ -0{r>,&Mm  
new TestMethod(); #S*/bao#  
} |\IN.W[EL  
} 2:7zG"$  
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