http断点续传简单实现（java)

/* ?papk4w  
**SiteFileFetch.java <R%TCVwC@  
*/ {qCFd  
package NetFox; `/B+  
import java.io.*; z+zEH9.'  
import java.net.*; J*Cf1 D5!  
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public class SiteFileFetch extends Thread { Q=#FvsF#z3  
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SiteInfoBean siteInfoBean = null; //文件信息Bean WfTl\Dxw  
long[] nStartPos; //开始位置 dqFp"
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long[] nEndPos; //结束位置 .CW,Td3f!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _E/  
long nFileLength; //文件长度 "2 :zWh7|  
boolean bFirst = true; //是否第一次取文件 @
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boolean bStop = false; //停止标志 2a 7"~z~  
File tmpFile; //文件下载的临时信息 /^X)>1)j  
DataOutputStream output; //输出到文件的输出流 -%V~1  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） oc[z dIk  
public SiteFileFetch(SiteInfoBean bean) throws IOException !>GDp>0  
{ jQBn\^w  
siteInfoBean = bean; HLc3KYIk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <$K7f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); f=8{cK0j  
if(tmpFile.exists ()) 4VC8#x1  
{ q_"w,28  
bFirst = false; b"OHXu  
read_nPos(); \}YAQ'T  
} m5,&;~  
else "QBl "<<s  
{ p )WRsJ8  
nStartPos = new long[bean.getNSplitter()]; J90 )v7  
nEndPos = new long[bean.getNSplitter()]; 4sC)hAx&f  
} X[SIk%{D  
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} (io[O?te  
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public void run() ^a1k"|E?f  
{ ,H$%'s1I(  
//获得文件长度 ,&Vir)S  
//分割文件 5FsfJpw  
//实例FileSplitterFetch FiXqypT_(  
//启动FileSplitterFetch线程 F4ylD5Y!  
//等待子线程返回 -av=5hm  
try{ n{M-t@r7  
if(bFirst) )d|s$l$?7  
{ #6pJw?[  
nFileLength = getFileSize(); ,)VAKrSg  
if(nFileLength == -1) {j4&'=C:  
{ G+I->n-s4  
System.err.println("File Length is not known!"); !:}m-iqQ1  
} Deq@T {  
else if(nFileLength == -2) ^)aj,U[  
{ _'n]rQ'  
System.err.println("File is not access!"); 9XUk.Nek  
} b%0@nu4  
else dh%
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{ V`1x!
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for(int i=0;i<nStartPos.length;i++) 6l2Os $  
{ u}rJqZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NH*"AE;  
} 7Rc>LI* '  
for(int i=0;i<nEndPos.length-1;i++) 6:Y2z!MLO  
{ D'^UZZlI^I  
nEndPos = nStartPos[i+1]; #Kx @:I  
} r>sXvzv  
nEndPos[nEndPos.length-1] = nFileLength; /fU-0a8  
} |C0!mU  
} bik lja  
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BaMF5f+  
//启动子线程 >ZU)bnndA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >X=VPh8  
for(int i=0;i<nStartPos.length;i++) /Kd'!lMuz  
{ Y)#,6\=U  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a :cfr*IsK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), YtXd>@7  
nStartPos,nEndPos,i); Oh,Xjel  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #5iwDAw:|r  
fileSplitterFetch.start(); $Yw~v36`t/  
} 8>
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Lg7dJnf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); p1T0FBV L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %MCS_'N J  
nEndPos = " + nFileLength); voJJoy%  
// fileSplitterFetch[nPos.length-1].start(); 7I;0%sVQ{  
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P:5vS:s?  
//等待子线程结束 =F5zU5`i  
//int count = 0; Tr;&bX5]H  
//是否结束while循环 7g%\+%F I  
boolean breakWhile = false; nHU}OGzW  
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while(!bStop) +k0UVZZX?  
{ ?30pNF|  
write_nPos();
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Utility.sleep(500); D z[,;  
breakWhile = true; Ylgr]?Db*  
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for(int i=0;i<nStartPos.length;i++) qca=a}  
{ Pu'NSNT  
if(!fileSplitterFetch.bDownOver) K@{R?j/+  
{ sLSH`Xy?5  
breakWhile = false; d ]#`?}  
break; [<>%I#7ulG  
}  @l&{ j  
} #vAqqAS`,  
if(breakWhile) V?-2FK]  
break; M'T[L%AP  
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//count++; V >~\~H2Y  
//if(count>4) ^S)t;t@x  
// siteStop(); 7ZUS  
} ~NO7@muw  
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Ri*mu*r\}  
System.err.println("文件下载结束！"); =Ew77  
} n;QFy5HB8  
catch(Exception e){e.printStackTrace ();} _:Jma  
} [fs.D /  
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//获得文件长度 >LB*5  
public long getFileSize() z$Qy<_l  
{ 1DN  
int nFileLength = -1; jLw|F-v-l<  
try{ -U;=]o1  
URL url = new URL(siteInfoBean.getSSiteURL()); c_aj-`BKp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -a'D~EGB^  
httpConnection.setRequestProperty("User-Agent","NetFox");  "Id1H  
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}  
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int responseCode=httpConnection.getResponseCode(); t Q.%f:|  
if(responseCode>=400) HHOqJb{8S  
{ AXv-%k};  
processErrorCode(responseCode); e488}h6#m  
return -2; //-2 represent access is error K 28s<i`  
} (-@I'CFd  
K
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String sHeader; v|@EuN14<  
jY ;Hdb''  
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for(int i=1;;i++) S8C}C
#  
{ E/gfX   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n8FIxl&u  
//Utility.log(in.readLine()); j{/5i`5m  
sHeader=httpConnection.getHeaderFieldKey(i); V}FH5z |  
if(sHeader!=null) 4{0vdpo3F  
{ Fu[GQ6{f  
if(sHeader.equals("Content-Length")) *zdUCX  
{ n-1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); P!{J28dj  
break; |\)Y,~;P  
} u]]mbER*t#  
} u_b6u@r7  
else n;>
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break; FS*J8)  
} shiw;.vR{B  
} %H3iX^}*  
catch(IOException e){e.printStackTrace ();} UgOhx-8  
catch(Exception e){e.printStackTrace ();} []?*}o5&>T  
/74)c~.W  
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Utility.log(nFileLength); ]}.|b6\  
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return nFileLength; Q,};O$h  
} 4Vd[cRh2  
gyU=v{].  
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//保存下载信息（文件指针位置） }}Gki
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private void write_nPos() '"h}l`  
{ .s|5AC[  
try{ q77Iq0VR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Pu'lp O  
output.writeInt(nStartPos.length); 6H0aHCM  
for(int i=0;i<nStartPos.length;i++) V8Z@y&ny  
{ ZbH_h]1$D  
// output.writeLong(nPos); j_b/66JyN  
output.writeLong(fileSplitterFetch.nStartPos); iaQFVROu  
output.writeLong(fileSplitterFetch.nEndPos); Z5`V\$  
} PH?<)Wj9i  
output.close(); ('.I)n  
} 8[a N5M]  
catch(IOException e){e.printStackTrace ();} ~h%H;wC&  
catch(Exception e){e.printStackTrace ();} E_{P^7Z|Jg  
} g O8~$Aj  
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//读取保存的下载信息（文件指针位置） rY$wC%  
private void read_nPos() MYVb !  
{ OK z5;#S=  
try{ WY26Iq@C  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); SzG?m]  
int nCount = input.readInt(); 46H@z=5  
nStartPos = new long[nCount]; [lzH%0 V  
nEndPos = new long[nCount]; }T53y6J#  
for(int i=0;i<nStartPos.length;i++) <d{>[R)  
{ ZR8y9mx2"  
nStartPos = input.readLong(); V-"#Kf9  
nEndPos = input.readLong(); !.O;S
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} %PPkT]~\  
input.close(); <irr.O  
} s,M]f,T  
catch(IOException e){e.printStackTrace ();} 8/~@3-9EK  
catch(Exception e){e.printStackTrace ();} ?}C8_I|4~  
} GxE`z6%[  
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private void processErrorCode(int nErrorCode) +KIBbXF7  
{ _
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System.err.println("Error Code : " + nErrorCode); -@~4:o  
} ,<TJh[TzC6  
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n+s=u$%qn  
//停止文件下载 f^Q)lIv  
public void siteStop() Q{~;4+ZD  
{ "DRiJ.|APs  
bStop = true; B.);Ju  
for(int i=0;i<nStartPos.length;i++) }x_:v!G  
fileSplitterFetch.splitterStop(); 1b@]^Ue  
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~  
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} FQ/z,it_i  
} i{r[zA]$  
//负责部分文件的抓取 Z,>owoP4  
**FileSplitterFetch.java (T.j3@Ko  
*/ eXkpU7w;  
package NetFox; &-Q_%eM^  
 &7eN EA  
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import java.io.*; =$_kkVQ$  
import java.net.*; p;mV?B?oAQ  
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public class FileSplitterFetch extends Thread { OSwum!hzN  
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String sURL; //File URL 2l~qzT-  
long nStartPos; //File Snippet Start Position 8w~X4A,  
long nEndPos; //File Snippet End Position 31p7oRzr  
int nThreadID; //Thread's ID g c<Y?a-  
boolean bDownOver = false; //Downing is over "rpP  
boolean bStop = false; //Stop identical 3RI%OCGF  
FileAccessI fileAccessI = null; //File Access interface 1WI^RlWd(  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %htwq]rZd  
{ /K<>OyR?  
this.sURL = sURL; iS`ok  
this.nStartPos = nStart; 6s$h _$[X  
this.nEndPos = nEnd; ?~oc4J*>(  
nThreadID = id; d[p?B-7%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 I"D}amuv  
} CxrsP.  
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public void run() 8>|<m'e^\r  
{ $|I hO  
while(nStartPos < nEndPos && !bStop) nHQWO   
{ !#PA#Q|cO  
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try{ 43*;"w=  
URL url = new URL(sURL); UW{C`^?=B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -+:t%A?  
httpConnection.setRequestProperty("User-Agent","NetFox"); cEK#5   
String sProperty = "bytes="+nStartPos+"-"; USKC,&6&}  
httpConnection.setRequestProperty("RANGE",sProperty); v|nt(-JX  
Utility.log(sProperty); <=%G%V_s  
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tYx>?~   
InputStream input = httpConnection.getInputStream(); )Dyyb1\)  
//logResponseHead(httpConnection); UryHte  
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byte[] b = new byte[1024]; 4XS
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int nRead; eRg;)[#0>$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >j&k:  
{ Mz;KXP  
nStartPos += fileAccessI.write(b,0,nRead); *~d<]U5h  
//if(nThreadID == 1) m>!aI?g  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b:$q5  
} UGP&&A#T-  
it->)?"(6  
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Utility.log("Thread " + nThreadID + " is over!"); ozl>Au  
bDownOver = true; K"Gea`I  
//nPos = fileAccessI.write (b,0,nRead); a#&\65D  
} $v=(`
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catch(Exception e){e.printStackTrace ();} Gy
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} <,JO  
} u`pw'3hY
 
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//打印回应的头信息 G~/*!?&z  
public void logResponseHead(HttpURLConnection con) 1{G@'#(  
{  k.\4<}  
for(int i=1;;i++) R4S))EHg  
{ UK.=Y9  
String header=con.getHeaderFieldKey(i); M[L@ej  
if(header!=null) X&A2:A 6\+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); F`.W 9H3
 
Utility.log(header+" : "+con.getHeaderField(header)); h@Ix9!?+  
else =27ZY Z  
break; AA}+37@2I  
} vhN6_XD  
} .GvZv>  
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public void splitterStop() PrF('PH7i  
{ 3lg
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bStop = true; x6Q_+!mnk  
} \psO$TxF=  
fF.+{-.  
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} R[H#av  
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/* 6.vwK3\>~  
**FileAccess.java 4r9AUmJqw  
*//文件访问(定位，写) 8cj}9}k  
package NetFox; ngzQVaB9  
import java.io.*; |2I/r$Q  
MF+F8h>/  
@ZtvpL}e  
public class FileAccessI implements Serializable{ TrBtTqH)  
X&!($*/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 DOq"=R+  
RandomAccessFile oSavedFile; MgHO WoF  
long nPos; y~wN:  
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public FileAccessI() throws IOException hjp,v)#  
{ -c%'f&P  
this("",0); cZAf?,>u  
} v=-T3 n  
+KIFLuL  
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public FileAccessI(String sName,long nPos) throws IOException Nk?/vMaw  
{ ]F"@+_E  
oSavedFile = new RandomAccessFile(sName,"rw"); {Vf].l:kn  
this.nPos = nPos; HyIyrUrYW  
oSavedFile.seek(nPos); `Nv7c{M^  
} KnUVR!H|  

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public synchronized int write(byte[] b,int nStart,int nLen) 4K >z?jd  
{ qG#ZYcVec  
int n = -1; \sS0@gnDI  
try{ (_fovV=  
oSavedFile.write(b,nStart,nLen); aQ0pYk~(  
n = nLen; ?qb
q\t  
} l^rQo_alk  
catch(IOException e) D~ 7W  
{ FMC]KXSd  
e.printStackTrace (); {G{>Qa|  
} |zOwC9-6  
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return n; n{"a0O  
} U
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} @Z Dd(xB&  
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4 Z&KR<2Z  
/* seZb;0  
**SiteInfoBean.java ^_uCSA'X  
*/ E*QLw*H  
package NetFox; iXqRX';F'}  
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ym2"D?P (  
public class SiteInfoBean {
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private String sSiteURL; //Site's URL mnU8i=v0A  
private String sFilePath; //Saved File's Path p+${_w>pl{  
private String sFileName; //Saved File's Name euET)Ccq  
private int nSplitter; //Count of Splited Downloading File b T** y?2  
cpphnGj5  
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public SiteInfoBean() V2$M`|E  
{//nSplitter的缺省值为5 '|G8yojz  
//default value of nSplitter is 5 [x -<O:r=P  
this("","","",5); {N@Pk[!  
} /b410NP5  
1+qP7 3a^  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) l6.&<0pLT  
{ ?3<Y/Vg%c  
sSiteURL= sURL; Fp>nu_-"  
sFilePath = sPath; s$ ?;C  
sFileName = sName; [ZS.6{vr  
this.nSplitter = nSpiltter; x::d}PP7  
,?w
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} f0*_& rP  
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public String getSSiteURL() =D)ADZ\<r  
{ r"dR}S.Uf  
return sSiteURL; *TPWLR ^  
} Y /l~R7  
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9rT"_d#  
public void setSSiteURL(String value) A|yU'k  
{ \!IEZ  
sSiteURL = value; P[jh^!<j  
} lz_ r  
c-4z8T#M^  
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public String getSFilePath() 6I
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{ 3=%G{L16-  
return sFilePath; '30JJ0  
} w^}*<q\  
7yOBxb   
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public void setSFilePath(String value) +R"n_6N  
{ (t,mtdD#1  
sFilePath = value; :0Fc E,1  
} ;

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18]Q4s8E  
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public String getSFileName() HstL'{&,-m  
{ ..=lM:13|  
return sFileName; 'h[7AZ&)#  
} Mo4c8wp&SM  
@2TfW]6  
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public void setSFileName(String value) x!u6LDq0  
{ )M8@|~~  
sFileName = value; zo@,>'m  
} gBZNO! a,d  
;Hb"SB  
=>7czw:S1  
public int getNSplitter() /Z]hX*QR  
{ Fzz9BEw(i  
return nSplitter; & d* bQv$  
}
UU '9  
::@JL  

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public void setNSplitter(int nCount) ajX] ui  
{ rw?wlBEG%  
nSplitter = nCount; 8yM8O #S  
} ?F~0\T,7  
} jH<,dG:{  
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/* KVoM\ttP  
**Utility.java AOx8OiqE:  
*/ 'Y]<1M>.g  
package NetFox; n,{  
${`q
!  
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public class Utility { .:tR*Kst`7  
"WH &BhQYD  
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public Utility() [5Zi\'~UH)  
{  nWUau:%  
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} #q8/=,3EG  
_,w*Rv5=  
//线程睡眠 FPEab69  
public static void sleep(int nSecond) /K_*Drk>  
{ OOYdrv,  
try{ 6L2Wv5C  
Thread.sleep(nSecond); @9\E  
} EdZNmL3cB  
catch(Exception e) xFyBF[c  
{ eGo$F2C6E  
e.printStackTrace (); 4ZB]n,pfT  
} NU[Wj uLG  
} >uE<-klv  
eYPIZ{S7h  
//日志 '@"A{mrE  
public static void log(String sMsg) vb`:  
{ qnO/4\qq  
System.err.println(sMsg); jjg&C9w T  
} $C8s  
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public static void log(int sMsg) .G|U#%"6x  
{ o^u}(wZ{  
System.err.println(sMsg); vQ[ TcV  
} E%$[*jZ  
} ictOCF  
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(
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/* ^L'<%_#.  
**TestMethod.java u#0EZ2>#  
*/ j0S[JpoF  
package NetFox; 7QaZ|\c  
A$TFa:O|  
Q|Nw @7$`  
public class TestMethod { :{?Pq8jP  
Ljk0K3Q6>  
Dj w#{WR  
public TestMethod() W;8}`k  
{ ///xx/weblogic60b2_win.exe s_6Iz^]I  
try{ H#QPcp@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); QtOT'<2t]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); P}-S[[b73s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {tnhP^C3>  
fileFetch.start(); t0)hdX  
} bbWW|PtWwP  
catch(Exception e){e.printStackTrace ();} W}
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1["IT.,f.  
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} ZMch2 U8  
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public static void main(String[] args) KPa&P:R3  
{ T2 V(P>E  
new TestMethod(); /fxv^C82yv  
} -yY]0  
} ?gS~9jgcd  
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