http断点续传简单实现（java)

/* =gj]R  
**SiteFileFetch.java ^yX W.s  
*/ \&cVcAg  
package NetFox; 3B_S>0H"$  
import java.io.*; A(C3kISM  
import java.net.*; g` Wr3  
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)S`A+M K]  
public class SiteFileFetch extends Thread { v\<`"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :O{:;X)  
long[] nStartPos; //开始位置 xv)7-jlx  
long[] nEndPos; //结束位置 ~
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 n"Ev25%  
long nFileLength; //文件长度 0 xXAhv-)O  
boolean bFirst = true; //是否第一次取文件 ]\GGC]:\@  
boolean bStop = false; //停止标志 Lrk^<:8;  
File tmpFile; //文件下载的临时信息 Wl*\kQ}U  
DataOutputStream output; //输出到文件的输出流 )Ev [o#y  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &r_:n t  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8>w/Es5  
{ O[N{&\$  
siteInfoBean = bean; 'al-C;Z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); u!F3Rh8D  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gs. K,xma  
if(tmpFile.exists ()) Yu8WmX,[  
{ ZGS=;jM  
bFirst = false; pIh@!C  
read_nPos(); ?1[go+56X  
} 2Aff3]-:Gd  
else |S.-
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{ j\W+wnAgk  
nStartPos = new long[bean.getNSplitter()]; ,CCIg9Pt  
nEndPos = new long[bean.getNSplitter()]; j6Vuj/+}  
} #$8tBo  
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#-@
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} 0z,c6MjM+  
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public void run() t4,6`d?C  
{ }U8H4B~UtY  
//获得文件长度 ysSEgC3  
//分割文件 f}@]dFr  
//实例FileSplitterFetch [jafPi(#g  
//启动FileSplitterFetch线程 YWm:#{n.  
//等待子线程返回 V+E2nJ  
try{ 1tD4I  
if(bFirst) hLBX,r)u  
{ &oAuh?kTq  
nFileLength = getFileSize(); d,$[633It}  
if(nFileLength == -1) [t0gXdU6  
{ @O4m-Oosi  
System.err.println("File Length is not known!"); ^d!-IL_  
} 0C3CqGP  
else if(nFileLength == -2) c.NAUe_3  
{ Ii;~ xc  
System.err.println("File is not access!"); }mX;0qO  
} u
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else :^px1  
{ FCOSgEU  
for(int i=0;i<nStartPos.length;i++) ]x~H"<V  
{ eoow]me  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "&7v.-Yk(  
} uI+h9j$vS  
for(int i=0;i<nEndPos.length-1;i++) #K  ]k  
{ *-gS u  
nEndPos = nStartPos[i+1];  M)Y`u  
} j#o0y
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nEndPos[nEndPos.length-1] = nFileLength;  x@Q}sW92  
} Z~$fTW6g  
} E@t^IGDr  
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0hCJovSG%  
//启动子线程 \O@,v0
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; KeY)%{  
for(int i=0;i<nStartPos.length;i++) YW}1Mf=_  
{ :Bda]]Y=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t[7YMk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *O+YhoR?  
nStartPos,nEndPos,i); NaLec|6<t  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1vi<@i,  
fileSplitterFetch.start(); IL`5RZi1  
} +d]}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8!E$0^)c|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |Q.t]TR'P  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6i,d|  
nEndPos = " + nFileLength); omY%sQ{)  
// fileSplitterFetch[nPos.length-1].start(); F5:4 B]ZF  
n omtP }  
NSj}
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//等待子线程结束 c.,eIiL  
//int count = 0; 61b,+'-  
//是否结束while循环 A'p"FYlCW  
boolean breakWhile = false; |$^,e%bE  
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while(!bStop) 7DXT1+t  
{ p
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write_nPos(); kR9G;IZ8s  
Utility.sleep(500); 0g~WM  
breakWhile = true; ^`Vt<DMT  
{SJ=|L6  
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for(int i=0;i<nStartPos.length;i++) I Yj\t?,0  
{ ey@y?X=  
if(!fileSplitterFetch.bDownOver) _hK7hvM>  
{ n-}.Yc  
breakWhile = false; ,m9Nd "6\  
break; &}wKC:LSP  
} p;U[cGHC  
} `yNNpSdS1  
if(breakWhile) Y)?4
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break; I?Hj,lN  
|C\g3N-  
&X9#{:l=  
//count++; 7f~DD8R  
//if(count>4) 's(0>i  
// siteStop(); +TfMj1Zx  
} 0&$e:O'v  
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System.err.println("文件下载结束！"); Lb{~a_c  
} 9v_gR52vh  
catch(Exception e){e.printStackTrace ();} 7a->"W  
} 8HxB\ !0F?  
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//获得文件长度 rX{QgyY&  
public long getFileSize() gh['T,  
{ [`yiD
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int nFileLength = -1; &:nWZ!D  
try{ A|c
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URL url = new URL(siteInfoBean.getSSiteURL()); j}X4#{jgC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hSQP '6  
httpConnection.setRequestProperty("User-Agent","NetFox"); oy;N3  
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d]} 7]  
int responseCode=httpConnection.getResponseCode(); NV^ktln  
if(responseCode>=400) P>0j]?RB  
{ pIqPIuy  
processErrorCode(responseCode); rPZ<  
return -2; //-2 represent access is error D-8%lGS
 
} N`Zm[Sv7  
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9c}LG5  
String sHeader; {Ejv8UdA9  
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for(int i=1;;i++) ;_F iiBk7(  
{ |rq~.cA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Go^W\y  
//Utility.log(in.readLine());  i('z~  
sHeader=httpConnection.getHeaderFieldKey(i); yaa+j8s]  
if(sHeader!=null) |U8;25Y  
{ {t;Q#Ou.  
if(sHeader.equals("Content-Length")) '_4u, \SG  
{ uY5f mM9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *J 7>6N:-  
break; 'i%Azzv  
} Z@RAdwjR`p  
} ePrbG4xv  
else Fu^^Jex  
break;  i/y+kL  
} ^pKC0E[%  
} '4L i  
catch(IOException e){e.printStackTrace ();} F'C]OMBE  
catch(Exception e){e.printStackTrace ();} 6(ju!pE`  
|2 g }i\  
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Utility.log(nFileLength); hh
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 &j2L-)  
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return nFileLength; u8~.6]Ae  
} ]Q6,,/nn  
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//保存下载信息（文件指针位置） E IsA2 f  
private void write_nPos() 4:nmo@K&~  
{ aS'G&(_  
try{ {1#5\t>9yD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1k-^LdDj  
output.writeInt(nStartPos.length); ]\+bx=  
for(int i=0;i<nStartPos.length;i++) [77]0V7  
{ s,]6Lri`\  
// output.writeLong(nPos); CImB,AXS  
output.writeLong(fileSplitterFetch.nStartPos); !r.X.C  
output.writeLong(fileSplitterFetch.nEndPos); \7$m[h{l  
} FOquQr1cF  
output.close(); Mf%/t HK  
} v9x $`  
catch(IOException e){e.printStackTrace ();} QI0ARdS  
catch(Exception e){e.printStackTrace ();} G\*`EM4  
} P-7!\[];te  
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//读取保存的下载信息（文件指针位置） i._d^lR\t  
private void read_nPos() L)y}  
{ U5dJ
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try{ eq(|%]a=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U87VaUr  
int nCount = input.readInt(); No=f&GVg  
nStartPos = new long[nCount]; h'MX{Wm.  
nEndPos = new long[nCount]; t{F6+dp  
for(int i=0;i<nStartPos.length;i++) o!sxfJKl  
{ cK@O)Ko}  
nStartPos = input.readLong(); unSF;S<  
nEndPos = input.readLong(); AH`tkPd  
} >J.a,!  
input.close(); 9oKRu6]D-  
} AJCWp4,  
catch(IOException e){e.printStackTrace ();} h&h]z[r R  
catch(Exception e){e.printStackTrace ();} yoGE#+|7^  
} va~:oA  
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private void processErrorCode(int nErrorCode) o1GWcxu*\  
{ D 67H56[  
System.err.println("Error Code : " + nErrorCode); _q3SR[k+`  
} a9
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//停止文件下载 [MFV:Z  
public void siteStop() ds5<4SLj  
{ Vxo3RwmR  
bStop = true; #uuwzE*M_  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); q^(
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} FRs5 Pb1  
} :L*CL 8m  
//负责部分文件的抓取 ^R>&^"oI  
**FileSplitterFetch.java _.?$~;7  
*/ rf1-E57#  
package NetFox; V9B $_j4  
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import java.io.*; ;2#7"a^  
import java.net.*; B<8Z?:3YS  
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public class FileSplitterFetch extends Thread { {P1W{|  
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String sURL; //File URL \-V  
long nStartPos; //File Snippet Start Position ZLE4XB]  
long nEndPos; //File Snippet End Position dXrv  
int nThreadID; //Thread's ID lYQcQ*-  
boolean bDownOver = false; //Downing is over ME0ivr*=:  
boolean bStop = false; //Stop identical ,h8)5Mj/J  
FileAccessI fileAccessI = null; //File Access interface ?>4^e:  
@105 @9F  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException NBUM* Z  
{ CFRo>G  
this.sURL = sURL; PuUqWW'^  
this.nStartPos = nStart; iCc@N|~  
this.nEndPos = nEnd; L.+5`&  
nThreadID = id; T3'dfeU  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 vERsrg;(  
} g>VkQos5"  
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;I5HMc_a"  
public void run() 3<'SnP3mY  
{ l#]Z?zW
.  
while(nStartPos < nEndPos && !bStop) |_!xA/_U'T  
{ /+02BP  
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try{ |}'}TYX0:  
URL url = new URL(sURL); 0o`0Td
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '3%!Gi!g  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z{u*vUC&  
String sProperty = "bytes="+nStartPos+"-"; pX6OhwkTK  
httpConnection.setRequestProperty("RANGE",sProperty); i1|-  
Utility.log(sProperty); )0qXZgs  
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InputStream input = httpConnection.getInputStream(); D/@:wY  
//logResponseHead(httpConnection); MEq ()}7P  
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byte[] b = new byte[1024]; X
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int nRead; 8.]dThaq  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B6$s*SXNp  
{ 9Z7o?S";  
nStartPos += fileAccessI.write(b,0,nRead); %DzS~5$G  
//if(nThreadID == 1) i"sVk8+o!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3#0nus|=S  
} G8akMd]2  
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a/`fJY6rR  
Utility.log("Thread " + nThreadID + " is over!"); +,c;Dff  
bDownOver = true; 7m@pdq5Ub  
//nPos = fileAccessI.write (b,0,nRead); ZNG.W0{p  
} .+{nfmc,c  
catch(Exception e){e.printStackTrace ();} Qzb8*;4?FF  
} UmInAH4  
} stoBjDS  
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uR@\/6!@  
//打印回应的头信息 9OXrz}8C  
public void logResponseHead(HttpURLConnection con) #r:J,D6*   
{ 1cOp"!  
for(int i=1;;i++) _RY<-B   
{ *C's7O{O  
String header=con.getHeaderFieldKey(i); B'atwgI0  
if(header!=null) H\^5>ccU>V  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q0DoR@  
Utility.log(header+" : "+con.getHeaderField(header)); tlq
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else @oYTJd(v{  
break; 6t/})Xv  
} |~v($c  
} ~g>15b
3  
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public void splitterStop() -^\k+4
;  
{ +apIp(E+  
bStop = true; sOU_j4M{  
} .yg"!X  
otX#}} +  
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} D1#E&4   
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[J-r*t"!  
/* kDO6:sjR7  
**FileAccess.java ~]c^v'k  
*//文件访问(定位，写) :qgdn,Me  
package NetFox; G9Azd^3  
import java.io.*; ,<pql!B-  
VJHHC.Kz  
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public class FileAccessI implements Serializable{ De:w(Rm  
},[S9I`p  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \mWXr*;  
RandomAccessFile oSavedFile; G.B^C)guu  
long nPos; Yn1U@!  
[.dNX  
)-9|3`  
public FileAccessI() throws IOException j] M)i:n  
{ TSHp.ABf  
this("",0); rYm<U!k  
} ?ADk`ts~,}  
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public FileAccessI(String sName,long nPos) throws IOException }1;Ie0l=_e  
{
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oSavedFile = new RandomAccessFile(sName,"rw"); 5:n&G[Md  
this.nPos = nPos; *p.ELI1IC  
oSavedFile.seek(nPos); >]C;sP  
} )2rI/=R  
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public synchronized int write(byte[] b,int nStart,int nLen) mO> [kb"V'  
{ A=h`Z^8\B  
int n = -1; 9h*$P:S;1v  
try{ QfwGf,0p  
oSavedFile.write(b,nStart,nLen); E8NIH!dI  
n = nLen; 9iS3.LCfX  
} |S>nfL{TQe  
catch(IOException e) o/=K:
5  
{ *jA%.F  
e.printStackTrace (); _}JygOew  
} ;y5cs;s
  
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return n; Z$WT ~V  
} wQ[2yq  
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} BAt2m-  
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/* vv%Di.V  
**SiteInfoBean.java G9VzVx#T#  
*/ \19XDqf8  
package NetFox; h)A+5^
:^  
Jw {:1  
?0_i{BvN  
public class SiteInfoBean { sBSBDjk[  
P<2yCovn`  
1N#TL"lMS  
private String sSiteURL; //Site's URL 5l)p5Bb48c  
private String sFilePath; //Saved File's Path q{ctHsQ(9  
private String sFileName; //Saved File's Name
4r5,kOFWb  
private int nSplitter; //Count of Splited Downloading File mX|AptND  
\ 2".Kb@=  
2d1'!B zDA  
public SiteInfoBean() n\cP17dr  
{//nSplitter的缺省值为5 1U"Y'y2  
//default value of nSplitter is 5 rx^pGVyg  
this("","","",5); *O 0*  
} pl"|NZz 7;  
3:=XU9p)x  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9sT?"(=  
{ Nw|Lrn*h!  
sSiteURL= sURL; z,]fR  
sFilePath = sPath; possM'vC  
sFileName = sName; \sRRLDj%  
this.nSplitter = nSpiltter; eY&UFe  
K7_)!=DcX  
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} ;j/ur\37  
I=3q#^}[  
1W/= =+%I  
public String getSSiteURL() Xr
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{ F48`1+  
return sSiteURL; 0kCUz  
} FAQ:0L$G  
sO(Kpo9jq  
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public void setSSiteURL(String value) ::M/s#-@  
{ YJ75dXc&&  
sSiteURL = value; -rH3rKtf~  
} C]r$  
aa".d[*1  
xH'H! 8  
public String getSFilePath() -Xd/-,zPY  
{ 4Y)3<=kDG  
return sFilePath; ipb
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} 5`z{A  
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public void setSFilePath(String value) x]
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{ L g%cVSz/C  
sFilePath = value; wCI.jGSBW  
} }_gq vgI>p  
y'zEaL&SI@  
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public String getSFileName() G
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{ }
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return sFileName; jf
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} zJx<]=]  
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s!+?)bB  
public void setSFileName(String value) >?tcL*  
{ 3~ZtAgih%  
sFileName = value;  vG  
} ;N/c5+  
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^#Wf  
public int getNSplitter() @FbzKHd
V/  
{ 
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return nSplitter; [S<DdTY9hZ  
} \dfq&oyU\  
->j9(76"  
,3Wa~\/Q  
public void setNSplitter(int nCount) !IGVN:E  
{ q,*IR*B:a  
nSplitter = nCount; De^is^{  
} H?aB8=)  
} 4bJ3uIP#  
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/* .<j8>1  
**Utility.java A2+t`[w  
*/ 95H`-A  
package NetFox; r[?rwc^  
", |wG7N K  
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public class Utility { 5Pr<%}[S^  
Z6 aT%7}}  
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public Utility() v:vA=R2  
{ %V+,#  
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} gF%ad=xm  
L@2H>Lh35  
//线程睡眠 $GPA6  
public static void sleep(int nSecond) ):\pD]e  
{ 7"QcvV@p  
try{ qQom=x  
Thread.sleep(nSecond); p,4z;.s$  
} 2dq{n.cgs  
catch(Exception e) Ti'O 2k  
{ ;wN.RPE_^  
e.printStackTrace (); 5q)Eed  
} Y

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} RSnK`N\9jb  
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//日志 *in_Zt3  
public static void log(String sMsg) +fwq9I>L  
{ $@U`zy
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System.err.println(sMsg); :J<S-d=  
} -meKaQv  
J

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public static void log(int sMsg) QHQj6]
 
{ ooD/QZUE  
System.err.println(sMsg); d6L(Q(:s  
} dE^'URBiA  
} U{R*WB b  
9S<W~# zz  
>a0;|;hp  
/* fkI<RgM  
**TestMethod.java w"sRK  
*/ I|PiZ1]2Y  
package NetFox; 7 yi>G  
{66vdAu&h<  
:._O.O  
public class TestMethod { vw!i)JO8M  
Wm\f:|U5`  
s+CWyW@  
public TestMethod() oZ=e/\[K  
{ ///xx/weblogic60b2_win.exe xCQ<G{;C  
try{ 7f(UbO@BD  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5
6v<!L5%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l p? h~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *$s)p>  
fileFetch.start(); JLeV@NO  
} `^6}Dn  
catch(Exception e){e.printStackTrace ();} ``NjNd  
C :e 'wmA  
c"QI`;D_c  
} zxj!ihs<  
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5i#B?+Y  
public static void main(String[] args) w S;(u[W  
{ ?,Hk]Rl3  
new TestMethod(); PC3wzJ\\S  
} |M0TG  
} wF&\@H  
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