http断点续传简单实现（java)

/* FC*[*  
**SiteFileFetch.java B?qjkP  
*/ j.kG};f  
package NetFox; y?:.;%!E  
import java.io.*; 2"5v[,$1H  
import java.net.*; C-[1iW'  
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?s _
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public class SiteFileFetch extends Thread { 2m[<]$  

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@A5?3(e  
SiteInfoBean siteInfoBean = null; //文件信息Bean C $JmzrE  
long[] nStartPos; //开始位置 1QJL .  
long[] nEndPos; //结束位置 #,.Hr#3nI  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]fD} ^s3G  
long nFileLength; //文件长度 jSAjcLR  
boolean bFirst = true; //是否第一次取文件 JG,%qFlk  
boolean bStop = false; //停止标志 qv"$Bd:]r  
File tmpFile; //文件下载的临时信息 hzRYec(  
DataOutputStream output; //输出到文件的输出流 nLiY%x`S  
[PM4k0YC8  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4H-'Dr=G  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3&/Ixm:  
{ FE{FGMq  
siteInfoBean = bean; 9M9?%N:ra  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); T5:G$-q
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F3N6{ysK#  
if(tmpFile.exists ()) hG:|9Sol,  
{ AvHCO8h|  
bFirst = false; I9Fr5p-%O  
read_nPos(); 6(e>P)  
} \_U$"/$4VH  
else ->{KVPHe{  
{ #!m.!? O  
nStartPos = new long[bean.getNSplitter()]; XGMiW0j0B  
nEndPos = new long[bean.getNSplitter()]; h65-s  
} D1mfm.9_r^  
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} 8h4'(yGQQW  
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public void run() zkdetrR  
{ s|B3~Q]  
//获得文件长度 :U(A;U1,  
//分割文件 IyPnp&_  
//实例FileSplitterFetch f>Jr|#k  
//启动FileSplitterFetch线程 ~F?u)~QZ#  
//等待子线程返回 BI}Cg{^km  
try{ -FlzEZ  
if(bFirst) {$Gd2gO  
{ O5t[  
nFileLength = getFileSize(); uc"P3,M  
if(nFileLength == -1) M {Q;:  
{ t>B;w14  
System.err.println("File Length is not known!"); A$xF$l  
} '!a'ZjYyi  
else if(nFileLength == -2) RlDn0s  
{ k,F6Tx  
System.err.println("File is not access!"); )Iq<+IJ  
} XNu^`Ha  
else H1(Uw:V8  
{ `%Al>u5  
for(int i=0;i<nStartPos.length;i++) U2~kJ  
{ r_;N
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); m<q
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} w~?~g<q  
for(int i=0;i<nEndPos.length-1;i++) [bNx^VP*  
{ E'.7xDN  
nEndPos = nStartPos[i+1]; JO"<{ngsQ  
} 3fJc 9|  
nEndPos[nEndPos.length-1] = nFileLength; }:*]aL<7_  
} f[^Aw(o  
} SrK<fAkx  
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3%;a)c;D  
//启动子线程 %zw1}|s#z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; j;iAD:nf  
for(int i=0;i<nStartPos.length;i++) &7wd?)s  
{ Jy
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P&e\)Z|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), T+k{W6  
nStartPos,nEndPos,i); e?ly
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w+E,INdi  
fileSplitterFetch.start(); pWsDzb6?%  
} QM#4uI55B  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), E5lBdM>2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )fSOi||C  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6s/&BR  
nEndPos = " + nFileLength); zEyN)  
// fileSplitterFetch[nPos.length-1].start(); 8-%TC\:  
!pdb'*,n  
K]"#C  
//等待子线程结束 P8)=Kbd  
//int count = 0; r_6ZO&  
//是否结束while循环 qd)/9*|Jl  
boolean breakWhile = false; > eIP.,9  
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:GP]P^M;G@  
while(!bStop) R1GEh&U{  
{ 9g"2^^wD  
write_nPos(); iv;Is[<o  
Utility.sleep(500); %H&@^Tt a  
breakWhile = true; TS9|a{j3!  
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#(JNn'
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for(int i=0;i<nStartPos.length;i++) QY?~ZwYB  
{ g^{@'}$  
if(!fileSplitterFetch.bDownOver) (HE9V]  
{ f;gw"onx8F  
breakWhile = false; Ww%=1M]e-  
break; dCk3;XU  
} DLMM/WJg@  
} 8UyMVY  
if(breakWhile) Y M\ K%rk  
break; "4+WZR]  
#32"=MfQn  
@u]rWVy;\[  
//count++; R:k5QD9/&p  
//if(count>4) E5xzy/ZQ  
// siteStop(); 1Y@Aixx  
} NzOo0tz:  
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A?%H=>v$  
System.err.println("文件下载结束！"); bc)~k:  
} G]i/nB  
catch(Exception e){e.printStackTrace ();} Hx*;jpy(2  
} ZUR6n>r  
*HO}~A%Lx  
^,8)iV0j_  
//获得文件长度 X+S9{X#Cm  
public long getFileSize() U`d5vEhT  
{ "C19b:4H  
int nFileLength = -1; An"</;HU  
try{ R0vIbFwj  
URL url = new URL(siteInfoBean.getSSiteURL()); Vz)`nmO}5\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m~u5kbHOi=  
httpConnection.setRequestProperty("User-Agent","NetFox"); WIf0z#JMJm  
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s
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int responseCode=httpConnection.getResponseCode(); h`k"A7M  
if(responseCode>=400) H{k
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{ CS-uNG6  
processErrorCode(responseCode); 3]UUG  
return -2; //-2 represent access is error
}'/`2!lY  
} %S nd\  
{
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String sHeader; G *;a^]-  
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for(int i=1;;i++) @8^
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{ yA(K=?sq  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [E JQ>?D  
//Utility.log(in.readLine()); ^__Dd)(  
sHeader=httpConnection.getHeaderFieldKey(i); \y)  
if(sHeader!=null) ``e$AS  
{ @u%_1  
if(sHeader.equals("Content-Length")) Kt|1&Gk  
{ ANSFdc  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); H& Ca
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break; mPP`xL?T  
} FR!? #!  
} #ap9Yoyk\  
else ,|plWIl~  
break; $3uKw!z  
} i?e`:}T  
} %\r!7@Q  
catch(IOException e){e.printStackTrace ();} J8)#PY[i4  
catch(Exception e){e.printStackTrace ();} H0SQ"?  
o b|BXF  
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Utility.log(nFileLength); '@CR\5 @  
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return nFileLength; Ox'/`Mppw  
} 9n5<]Q(  
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//保存下载信息（文件指针位置） Y.U[wL>  
private void write_nPos() 0`A~HH}  
{ @%
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try{ |7pR)KH3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,b;{emX h  
output.writeInt(nStartPos.length); UNi`P9D]3  
for(int i=0;i<nStartPos.length;i++) AT)a :i  
{ 7ei|XfR  
// output.writeLong(nPos); /?1nHBYPM  
output.writeLong(fileSplitterFetch.nStartPos); U Gpu\TB  
output.writeLong(fileSplitterFetch.nEndPos); n[,w f9  
} >ap1"n9k  
output.close(); dG71*)<)t  
} !\;FNu8_.  
catch(IOException e){e.printStackTrace ();} \7 NpT}dj  
catch(Exception e){e.printStackTrace ();} I1>N4R-j  
} ?k|H3;\  
l-$uHHyu*  
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//读取保存的下载信息（文件指针位置） i^!ez5z  
private void read_nPos() d{de6 `  
{ ~w;]c_{.b  
try{ AkT<2H|4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); D\YE^8/  
int nCount = input.readInt(); >xn}N6Rj2~  
nStartPos = new long[nCount]; awUx=%ERtA  
nEndPos = new long[nCount]; #vqo -y7@  
for(int i=0;i<nStartPos.length;i++) 9A7@ 5F  
{ wB{;bB{  
nStartPos = input.readLong(); *cg( ?yg  
nEndPos = input.readLong(); 3u\;j; Td!  
} GzTq5uU&  
input.close(); ]}6w#)]"  
} =?(~aV  
catch(IOException e){e.printStackTrace ();} ^Mk%z9 ?  
catch(Exception e){e.printStackTrace ();} W Qc>  
} '2-oh  
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*I?Eb-!t  
private void processErrorCode(int nErrorCode) M8b4NF_&  
{ ;|cTHGxbE  
System.err.println("Error Code : " + nErrorCode); |uH%6&\  
} "uPy,<l  
*+b6B_u]  
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//停止文件下载 *$M'`
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public void siteStop() .~gl19#:
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{ STA4 p6  
bStop = true; w_iamqe,  
for(int i=0;i<nStartPos.length;i++) ^R$'eG 4L?  
fileSplitterFetch.splitterStop(); h !(>7/Gi  
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} Y3ZK%OyPR  
} ib0g3p-Lc  
//负责部分文件的抓取 ^ 2u/n  
**FileSplitterFetch.java swc@34ei\  
*/ S2VVv$r_6  
package NetFox; ARfRsPxr  
mty1p'^KQ  
d=]U_+  
import java.io.*; SgE/!+{  
import java.net.*; 1
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=qvZpB7ZZ  
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public class FileSplitterFetch extends Thread { br,+45:  
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s-VSH  
String sURL; //File URL ?4)v`*  
long nStartPos; //File Snippet Start Position ev>oC~>s  
long nEndPos; //File Snippet End Position R.1Xst &i  
int nThreadID; //Thread's ID 0D)`2W  
boolean bDownOver = false; //Downing is over c/u_KJFF-n  
boolean bStop = false; //Stop identical LN!W(n(  
FileAccessI fileAccessI = null; //File Access interface 8kW/DcLE  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g*]E>SQ=  
{ En9R>A;`  
this.sURL = sURL; +CTmcbyOi  
this.nStartPos = nStart; <Ns &b.\h6  
this.nEndPos = nEnd; "~p+0Xws9  
nThreadID = id; nJVp.*S  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Xi~9&ed#$i  
} )45_]tk>  
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public void run() A'"-m)1P  
{ !z=pP$81  
while(nStartPos < nEndPos && !bStop) Ob(leL>ow  
{ qiNliJ>40E  
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try{ [b5(XIGUN}  
URL url = new URL(sURL); gEKO128  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]M4NpUM  
httpConnection.setRequestProperty("User-Agent","NetFox"); <7gMl  
String sProperty = "bytes="+nStartPos+"-"; YhgUCF#  
httpConnection.setRequestProperty("RANGE",sProperty); XZ:1!;  
Utility.log(sProperty); !s-/0ugZ  
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InputStream input = httpConnection.getInputStream(); B/Ba
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//logResponseHead(httpConnection); b|E/LKa  
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byte[] b = new byte[1024]; ~N[|bPRmhE  
int nRead; !3KPwI,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) KF$%q((  
{ +{xG<Wkltz  
nStartPos += fileAccessI.write(b,0,nRead); 1b`G2?%  
//if(nThreadID == 1)
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X RRJ)}P  
}
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Utility.log("Thread " + nThreadID + " is over!"); U$$3'n  
bDownOver = true; 4(iS-8{J  
//nPos = fileAccessI.write (b,0,nRead); AJWLEc4XK  
} QX/]gX  
catch(Exception e){e.printStackTrace ();} B'/Icg.T  
} v|To+P6b  
} ^8\Y`Z0%  
A[RN-R,  
a^*B5G1(&  
//打印回应的头信息 165WO}(;/  
public void logResponseHead(HttpURLConnection con) ZE ^u.>5  
{ \#_@qHAG  
for(int i=1;;i++) Znq(R8BMW  
{ V*kznm  
String header=con.getHeaderFieldKey(i); ! fX9*0L  
if(header!=null) Z c<]^QR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); AYYRxhv_,  
Utility.log(header+" : "+con.getHeaderField(header)); V!}L<cN  
else 1+FYjh!2t  
break; >T(M0Tkt  
} 1S^'C2/b  
} x:vrK#8D>  
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public void splitterStop() 78^Y;2 P]W  
{ pV_}Or_  
bStop = true; 0ZFB4GL  
} 7ia"
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} cy9N:MR(c  
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/* 8R BDJ  
**FileAccess.java ]C+eJ0"A  
*//文件访问(定位，写) _y|[Z;  
package NetFox; iczs8gj*  
import java.io.*; x ru(Le}E  
%~ ;nlDw  
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public class FileAccessI implements Serializable{ f*UBigk  
Mi_[9ku>%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `9]P/J^  
RandomAccessFile oSavedFile; J: L-15  
long nPos; WvIK=fdZ$  
bbM4A! N  
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public FileAccessI() throws IOException sTJJE3TBI  
{ YAX #O\,  
this("",0); Qu!OV]Cc  
} axHxqhO7zp  
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public FileAccessI(String sName,long nPos) throws IOException @2QJm
 
{ i%#th'C!P  
oSavedFile = new RandomAccessFile(sName,"rw"); -t;?P2  
this.nPos = nPos; Rc;1Sm9\  
oSavedFile.seek(nPos); 8/Lu'rI  
} Xcs8zT  
:d, >d  
X%RQB$  
public synchronized int write(byte[] b,int nStart,int nLen) PEMxoe<+  
{ |p'_k(z}  
int n = -1; h[vAU 9f)  
try{ ke{DFqh  
oSavedFile.write(b,nStart,nLen); $Vd?K@W[h  
n = nLen; qb#V)  
} _SU,f>  
catch(IOException e) lr)G:I#|  
{ $IZ*|>(  
e.printStackTrace (); s0x@ u  
} qpH j4  
/&y,vkZTT  
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return n; Pcdi  
} 8^&fZL',  
! hOOpZf7  
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} H620vlC}V  
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/* NB~*sP-l&  
**SiteInfoBean.java p{('KE)  
*/ Br_3qJNVP  
package NetFox; U"jUMOMZ;  
<m|FccvQ  
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public class SiteInfoBean { krnvFZRTQ  
h8Dtq5t4  
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private String sSiteURL; //Site's URL Gl3 `e&7  
private String sFilePath; //Saved File's Path ee__3>H"/  
private String sFileName; //Saved File's Name rd f85%%7  
private int nSplitter; //Count of Splited Downloading File ?j},O=JFn  

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*<#]&2I  
public SiteInfoBean() %'K+$  
{//nSplitter的缺省值为5 .)oQM:F(h  
//default value of nSplitter is 5 uC <|T  
this("","","",5); &q"uy:Rd  
} 7KYF16A4  
uWM4O@Qn)d  
g[uE@Gaj&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) x<)!$cg  
{ hfP(N_""S  
sSiteURL= sURL; VH$\ a~|  
sFilePath = sPath; `UzCq06rJ1  
sFileName = sName; M[&.kH  
this.nSplitter = nSpiltter; HzFt
 

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j[Hg]  
} DVeF(Y3&  
@Reh?]# v  
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public String getSSiteURL() j
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{ =qVAvo'  
return sSiteURL; KJ05Zx~uma  
} Rwi5+;N  
<#J<QYF&2  
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public void setSSiteURL(String value) MXu+I,y*  
{ E(L^hZMc  
sSiteURL = value; $$)<(MP3  
} .WPuQZ!  
)Uoe~\  
/Wta$!X{-  
public String getSFilePath() oGU.U9~!  
{ o 2$<>1^  
return sFilePath; d<^6hF  
} 8?]%Qi  
=-#iXP@  
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public void setSFilePath(String value) 1&x0+~G  
{ x Ps&CyI  
sFilePath = value; ! a8h  
} Av[|.~g  
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GO&RR}  
public String getSFileName() xf3/<x!B  
{ jDkc~Wwa  
return sFileName; vzgudxG'z  
} pQ6t]DJ4  
x,@O:e  
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public void setSFileName(String value) 4$#ia F  
{ M KE[Yb?  
sFileName = value; DNTRLIKa  
} ,YuWz$aF{  
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public int getNSplitter() 'e
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{ @a{v>)  
return nSplitter; S@rsQ@PA  
} IcNIuv  
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!&:.Uh  
public void setNSplitter(int nCount) A'P}mrY  
{ j^R~ Lt4  
nSplitter = nCount; W(3~F2  
} e?'k[ES^  
} .LVOaxT  
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F$pd]F!#  
/* & m";D  
**Utility.java -O
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*/
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package NetFox; 5;uX"zG  
^[,1+WS%  
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public class Utility { 1=cfk#  
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public Utility() OA5md9P;d  
{ T;vPR,]rz  
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} MyS7AL   
'c\TMb.  
//线程睡眠 b|C,b"$N0  
public static void sleep(int nSecond) "7u"d4h-:(  
{ H@bm
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try{ 7'
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Thread.sleep(nSecond); C{Xk/Er5<  
} *d*;M>  
catch(Exception e) |"(3]f\  
{ zAdVJ58H  
e.printStackTrace (); ? Gu_UW  
} _O71r}4  
} '/)_{Ly  
+,w|
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//日志 Hr.JZ>~<  
public static void log(String sMsg) eEb1R}@  
{ F1]PYx$X  
System.err.println(sMsg); pz
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} J##X5'a3*  
'S-"*:$,u  
%b'VEd7  
public static void log(int sMsg) 74N\G1  
{ rnrx%
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System.err.println(sMsg); `e69kBAm  
} MrjB[3Td  
} %^BOYvPx  
i: uA&9  
[==Z1Q;=  
/* ]3cf}Au  
**TestMethod.java 0a-:x4  
*/ u~Cqdr5 \l  
package NetFox; I&@@v\$*  
\.-y LS.  
FbT&w4Um=  
public class TestMethod { ].+G-<.:  
~Am %%$  
[ESQD5&  
public TestMethod() "f$A0RL  
{ ///xx/weblogic60b2_win.exe OnPLz"-  
try{ ue2nfp  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); u,k8i:JY  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2\W<EWJ@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -5*;J&.  
fileFetch.start(); ^x#RUv  
} KTREOOu .t  
catch(Exception e){e.printStackTrace ();} S~9kp?kR$  
w3hL.Z,kV  
|
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} B_G7
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\) ONy9  
public static void main(String[] args) ?UZyu4O%  
{ GM92yi!8  
new TestMethod(); +:8YMM#9V  
} eEFT(e5.>3  
} Z ' 96d  
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