http断点续传简单实现（java)

/* 69 J4p=c,  
**SiteFileFetch.java Of#"nu  
*/ tm.&k6%  
package NetFox; cR/e Zfl  
import java.io.*; Gh}* <X;N  
import java.net.*; hyY^$p+  
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public class SiteFileFetch extends Thread { ZU`HaL$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1[-RIN;U8  
long[] nStartPos; //开始位置 rIX 40,`  
long[] nEndPos; //结束位置 !Pu7%nV.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \==Mgy2J8  
long nFileLength; //文件长度 r;O?`~2'4  
boolean bFirst = true; //是否第一次取文件 M"foP@  
boolean bStop = false; //停止标志 Pr,C)uch  
File tmpFile; //文件下载的临时信息 _MTvNs  
DataOutputStream output; //输出到文件的输出流 q)PSHr=Z  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） D>kkA|>  
public SiteFileFetch(SiteInfoBean bean) throws IOException
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{ tPDB'S:&
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siteInfoBean = bean; X^C $|:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]j.!   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); w$`u_P|@E:  
if(tmpFile.exists ()) }mS Q!"f:  
{ ltHuN;C\  
bFirst = false; n.A*(@noe  
read_nPos(); xOZvQ\%  
} Q;@w\_OR  
else HS|x  
{ :I^4ILQCD  
nStartPos = new long[bean.getNSplitter()]; M#yUdl7d  
nEndPos = new long[bean.getNSplitter()]; <#~n+,  
} R%JEx3)0m  
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} Y5TBWcGU%  
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public void run() s%
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{ V{{UsEVO  
//获得文件长度 WX+@<y}%  
//分割文件 t5QGXj  
//实例FileSplitterFetch FYK}AR<=  
//启动FileSplitterFetch线程 ve4QS P  
//等待子线程返回 *T{KpiuP  
try{ Ds\f?\Em  
if(bFirst) )EG-
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{ xH-} <7  
nFileLength = getFileSize(); 5;9.&f  
if(nFileLength == -1) V.[b${  
{ |h:3BV_  
System.err.println("File Length is not known!"); }Ub "Vb  
} [{J1b  
else if(nFileLength == -2) &jDRRT3  
{ tdC kvVE  
System.err.println("File is not access!"); 1'5!")r  
} * =O@D2g0  
else gKb5W094@  
{ l_x>.'a  
for(int i=0;i<nStartPos.length;i++) h#8{fr)6  
{ hy:K) _   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); bre6SP@  
} U7G|4(  
for(int i=0;i<nEndPos.length-1;i++) !" : arK  
{ 1xwq:vFC.  
nEndPos = nStartPos[i+1]; &J=x[{R  
} S*rcXG6Q^  
nEndPos[nEndPos.length-1] = nFileLength; YGLR%PYv"  
} gOk^("@  
} n6*; ~h5  
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/h@rLJ)o>  
//启动子线程 q{.~=~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %;G!gJeE  
for(int i=0;i<nStartPos.length;i++) 2K'}Vm+  
{ ^[zF IO  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Pq( )2B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {K2F(kz?T  
nStartPos,nEndPos,i); "2@Ys*e  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Vs[!WJ 7  
fileSplitterFetch.start(); POQ1K O  
} LZu_-I  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5TdI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W&^2Fb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", F^');8~L  
nEndPos = " + nFileLength); @yjui  
// fileSplitterFetch[nPos.length-1].start(); #/pZ#ny  
II_MY#0X  
4>@-1nt}  
//等待子线程结束 KL*UU,qU  
//int count = 0; k?=V?JWY
 
//是否结束while循环 &nZ.$UK<  
boolean breakWhile = false; j8p'B-yS  
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while(!bStop) Z8Clm:S  
{ AwL;-|X  
write_nPos(); [h2V9>4:  
Utility.sleep(500); @KYmkxW  
breakWhile = true; e3>k"  
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for(int i=0;i<nStartPos.length;i++) iF]vIg#h  
{ G,i%:my7  
if(!fileSplitterFetch.bDownOver) gM3gc;  
{ Qod2m$>wp}  
breakWhile = false; >Y/1%Hp9  
break; z'X_s.9F  
} :ui1]its4  
}
]# T9v06w  
if(breakWhile) WJL,L[XC  
break; ]t3 NA*mM  
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]j:Ikb}  
//count++; `P4qEsZE>`  
//if(count>4) VVje|T^{Z  
// siteStop(); }fs;yPl,  
} )+9D$m=P;  
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System.err.println("文件下载结束！"); z95V 7E  
} Bf88f<Z  
catch(Exception e){e.printStackTrace ();} Qi7^z;  
} J0|}u1?l  
{1YT a:evl  
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//获得文件长度 @w:sNX
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public long getFileSize() ;h3*MR  
{ &f qmO>M  
int nFileLength = -1; :<IW'  
try{ ikRIL2Y  
URL url = new URL(siteInfoBean.getSSiteURL()); |@-WC.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o6KBJx  
httpConnection.setRequestProperty("User-Agent","NetFox"); jIc;jjAF  
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int responseCode=httpConnection.getResponseCode(); 9e :E% 2  
if(responseCode>=400) C127he  
{ l7J_s
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processErrorCode(responseCode); T[q-$8U  
return -2; //-2 represent access is error I}v'n{5(  
} )SUN+YV^  
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String sHeader; W\<#`0tUt  
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for(int i=1;;i++) #-HN[U?Gs  
{ =\%>O7c,8Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); qryt1~Dq  
//Utility.log(in.readLine()); 3Ob"r`  
sHeader=httpConnection.getHeaderFieldKey(i); -;`W"&`ss  
if(sHeader!=null) 4+k:j=x  
{ '7*=m^pc  
if(sHeader.equals("Content-Length")) $=m17GD  
{ RLHe;-*b]I  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M*S5&x
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break; fp![Pbms.  
} dju&Ku  
} >;3c;nf  
else >6DY3\  
break; hy)RV=X  
} xf]4!zE  
} VD#^Xy4% r  
catch(IOException e){e.printStackTrace ();} !d0@^JbM"  
catch(Exception e){e.printStackTrace ();} l*m|b""].u  
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Utility.log(nFileLength); S~Hj. d4/  
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return nFileLength; : }IS=A  
} .CpF
0  
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//保存下载信息（文件指针位置） oV!9B-<  
private void write_nPos() 5~"=Fm<uD  
{ ]Ojt3)fB  
try{ sk3;;<H  
output = new DataOutputStream(new FileOutputStream(tmpFile)); GQZUC\cB  
output.writeInt(nStartPos.length); J;kbY9e  
for(int i=0;i<nStartPos.length;i++) j5)qF1W,  
{ 7=AKQ7BB>b  
// output.writeLong(nPos); 5#F+-9r  
output.writeLong(fileSplitterFetch.nStartPos); `c
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output.writeLong(fileSplitterFetch.nEndPos); ha),N<'  
} >PJ-Z~O'   
output.close(); 5k(#kyP  
} fIcv}Y  
catch(IOException e){e.printStackTrace ();} E0pQRGPA  
catch(Exception e){e.printStackTrace ();} 5y'Yosy:  
} l&A`  
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//读取保存的下载信息（文件指针位置） f\^QV  
private void read_nPos() E{ ,O}  
{ 7@"
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try{ z} \9/`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <FK><aA_i*  
int nCount = input.readInt(); W%W. +f  
nStartPos = new long[nCount]; QaO`:wJj  
nEndPos = new long[nCount]; ^>p [b  
for(int i=0;i<nStartPos.length;i++) ]xG4T>S  
{ YBO53S]=  
nStartPos = input.readLong(); MnI $%  
nEndPos = input.readLong(); L' pZ  
} eBV{B70k  
input.close(); 7| T:TbY>  
} i=a LC*@  
catch(IOException e){e.printStackTrace ();} @6!JW(,]\  
catch(Exception e){e.printStackTrace ();} `+o.w#cl  
} =KZ4:d5  
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private void processErrorCode(int nErrorCode) N [
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{ \}=b/FL=U  
System.err.println("Error Code : " + nErrorCode); Chup %F  
} |@HdTGD  
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//停止文件下载 +*DX(v"BH  
public void siteStop() >cNXB7]E>  
{ -DnK)u\@  
bStop = true; {ybuHC  
for(int i=0;i<nStartPos.length;i++) q':wSu u  
fileSplitterFetch.splitterStop(); d
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} w0!,1 Ry  
} 9%qMZP0]  
//负责部分文件的抓取 Mg$9'a"[\
 
**FileSplitterFetch.java uLM_KZ  
*/ Fzs'@*  
package NetFox; Fc~w`~tv  
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import java.io.*; /8>/"Z2S  
import java.net.*; 0Y2^}u@5  
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public class FileSplitterFetch extends Thread { e;5Lv9?C8  
)''wu\7A)'  
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String sURL; //File URL )1
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long nStartPos; //File Snippet Start Position J#DcT@  
long nEndPos; //File Snippet End Position HJR<d&l;p  
int nThreadID; //Thread's ID zYdtQ
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boolean bDownOver = false; //Downing is over bl?%:qb.V  
boolean bStop = false; //Stop identical )
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FileAccessI fileAccessI = null; //File Access interface )<F\IM  
}Xi#x*-D  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException t`,IW{  
{ ZD%_PgiT  
this.sURL = sURL; q'U5QyuC  
this.nStartPos = nStart; mN 6`8 [  
this.nEndPos = nEnd; it@}dZ  
nThreadID = id; Y0\\(0j64  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &R*5;/ !  
} b,R'T+4[  
w
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public void run() ~+egu89'TU  
{ jYX9;C;J  
while(nStartPos < nEndPos && !bStop) ~!F4JRf  
{ 5I1J)K;  
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try{  ,nR8l  
URL url = new URL(sURL);
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |u r~s$8y-  
httpConnection.setRequestProperty("User-Agent","NetFox"); YB~t|m65  
String sProperty = "bytes="+nStartPos+"-"; j(C UYm  
httpConnection.setRequestProperty("RANGE",sProperty); ~<- ci  
Utility.log(sProperty); V?59.TJ  
t} i97;  
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InputStream input = httpConnection.getInputStream(); H#6^-6;/  
//logResponseHead(httpConnection); .Pes{uHg  
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byte[] b = new byte[1024]; |QOJ9~hxD  
int nRead; E 'JC  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qmeml_(W  
{ ,Kf8T9z`  
nStartPos += fileAccessI.write(b,0,nRead); -wQ^oOJ  
//if(nThreadID == 1)  7EP|X.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]esLAo  
} `]P5,  
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Utility.log("Thread " + nThreadID + " is over!"); #2R%H.*t  
bDownOver = true; w<e;rKr  
//nPos = fileAccessI.write (b,0,nRead); =l4\4td9p  
} iEVA[xy=D  
catch(Exception e){e.printStackTrace ();} | 58!A]  
} AY'?Xt  
} ,&&M|,NQ&s  
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//打印回应的头信息 eSX[J6  
public void logResponseHead(HttpURLConnection con) !x$:8R  
{ `XSc >  
for(int i=1;;i++) Lp`<L-s  
{ xGEmrE<;  
String header=con.getHeaderFieldKey(i); ^]qV8
 
if(header!=null) 2\63&C^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 3zTE4pHzu+  
Utility.log(header+" : "+con.getHeaderField(header)); fj-pNl6Gf  
else 2"+x(Ax  
break; P%@rH@^Y  
} :{b6M/  
} RmWfV  
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public void splitterStop() 6~F#F)C'  
{ c Z6p^  
bStop = true; |\%F(d330  
} 3> \fP#oQ  
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} =Etwa  
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/* Vv]$\`d
#  
**FileAccess.java Q5y q"/=[a  
*//文件访问(定位，写) ";_K x={  
package NetFox; PG6L]o^  
import java.io.*; 7mn,{2  
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public class FileAccessI implements Serializable{ UOu
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 R] Disljq  
RandomAccessFile oSavedFile; "VDk1YX_&l  
long nPos; G&@-R{i  
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public FileAccessI() throws IOException Ep<!zO|  
{ QP$nDK<  
this("",0); s`#ntset0  
} 4\1wyN /}M  
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public FileAccessI(String sName,long nPos) throws IOException (L y%{ Y  
{ i<#h]o C}  
oSavedFile = new RandomAccessFile(sName,"rw"); 
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this.nPos = nPos; G}P)vfcH  
oSavedFile.seek(nPos); MOP]\ypn  
} $v:gBlj%"  
}O.LPQ0  
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public synchronized int write(byte[] b,int nStart,int nLen) :'d76pM-  
{ emv;m/&8  
int n = -1; (|<h^] y3  
try{ Bw3F7W~l  
oSavedFile.write(b,nStart,nLen); p;qRm} 0}  
n = nLen; h-r6PY=i  
} Nt zq"ces)  
catch(IOException e) QT1:>k  
{ l5=u3r9WYC  
e.printStackTrace (); GB<R7J  
} zP:~O  
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return n; k;;nE o~6
 
} WYwzo V-  
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} rWoe ?g  
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/B,B4JI)/  
/* ?CH?kP  
**SiteInfoBean.java j`2B}@2  
*/ MV0<^/p|  
package NetFox; 4ef*9|^x#  
a
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#0P!xZ'|{  
public class SiteInfoBean { ;JOD!|  
"H5&3sF2  
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private String sSiteURL; //Site's URL |x d@M-ln  
private String sFilePath; //Saved File's Path j:HH#U  
private String sFileName; //Saved File's Name A$7Eo`Of  
private int nSplitter; //Count of Splited Downloading File 7<EJo$-j  
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public SiteInfoBean() ,^.S0;D,Z  
{//nSplitter的缺省值为5 s8t f@H4r  
//default value of nSplitter is 5 5R,la\!bQ  
this("","","",5); $42Au2Jg  
} E7rX1YdR  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) H9%l?r5  
{ [urH a  
sSiteURL= sURL; =LXvlt'Q34  
sFilePath = sPath; `]K,'i{R  
sFileName = sName; 4dW3'"R"L  
this.nSplitter = nSpiltter; yDd=& T   
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} HG3.~ 6X  
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public String getSSiteURL() X!T|07#c  
{ TkA9tF
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return sSiteURL; \4OK!6LkI  
} 7 ,$axvLw  
R `;o!B}[  
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public void setSSiteURL(String value) Dp!;7e s|  
{ _kh>Z  
sSiteURL = value; BiA>QQ  
} Ru)(dvk
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e@[9C(5E"  
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public String getSFilePath() \C|;F  
{ w3<Z?lj:  
return sFilePath; EtGH\?d~]  
} ?Rlgv5P!  
2[.5oz`  
R @"`~#$$  
public void setSFilePath(String value) >[K0=nA  
{ 9#u}^t  
sFilePath = value; {U(Bfe^a,  
} w]n4KR4  
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public String getSFileName() y0;,dv]  
{
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return sFileName; (%i!%{!]  
} l#Yx
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public void setSFileName(String value) bpGzTU  
{ CP +4k.)*O  
sFileName = value; Wt(Kd5k0'2  
} ?;Un#6b  
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public int getNSplitter() .Nc_n5D
6  
{ -=}b;Kf-  
return nSplitter; rWJ*e Y  
} \kxh#{$z?  
TNx_Rc}  
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public void setNSplitter(int nCount) g+.0c=G(  
{ T\jAk+$Jo  
nSplitter = nCount; mIRAS"Q!m  
} C}9Kx }q  
} &uPDZ#C-  
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/* Hv3W{
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**Utility.java (e(Rr4  
*/ )R~a;?T_c0  
package NetFox; 1f<RyAE?5  
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O5O.><RP  
public class Utility {
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4X*Q6rW  
Uh*@BmDA  
public Utility() N^lAG"Jao[  
{ F,zG;_  
7g5@vYS+  
4HW;  
} 0#<WOns1   
#J\s%60pt  
//线程睡眠 Jns/v6  
public static void sleep(int nSecond) ~ibF M5m  
{ nz[ m3]  
try{ :Z[(A"dA  
Thread.sleep(nSecond); hl**zF  
} OMvT;Vgg  
catch(Exception e) A0OB$OK  
{ 0TmZ*?3!4  
e.printStackTrace (); O~atNrHD  
} *.o"ZVl  
} 5*Btb#:  
G~(&3  
//日志 JDKLKHOMZ  
public static void log(String sMsg) 7/ t:YBR  
{ fQO ""qh  
System.err.println(sMsg); /~tP7<7A  
} :WO{xg  
*t]v}ZV*  
!U
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public static void log(int sMsg) >O3IfS(l  
{ z-I|h~ii  
System.err.println(sMsg); &y\igX1  
} M|H2kvl  
} Y0}4WWV  
8 ip^]  
Fo(y7$33*  
/* /S[?{QA  
**TestMethod.java 14-]esSa  
*/ TA|s@T{  
package NetFox; ; [FLT:$  
ly=a>}F_  
#N$9u"8C  
public class TestMethod { zIm-X,~I$  
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2  
public TestMethod() Wj tft%  
{ ///xx/weblogic60b2_win.exe %{"dP%|w4}  
try{ }
jiK3?e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^7^2D2[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TL'0T,Jo  
SiteFileFetch fileFetch = new SiteFileFetch(bean); OJ>iq@>  
fileFetch.start(); a%*_2#  
} (0}j]p'w  
catch(Exception e){e.printStackTrace ();} SiR\a!,C  
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} 4DM*^=9E  

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^)<w*iqBD  
public static void main(String[] args) gyFr"9';c  
{ aj v}JV&:  
new TestMethod(); Wc\+x1:8  
} Eu4 &-i  
} ,J&9kYz  
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