http断点续传简单实现（java)

/* ct,Iu+HJ  
**SiteFileFetch.java %]~XbO  
*/ K2=`.  
package NetFox; o_!=-AWV  
import java.io.*; m-{t%[Y  
import java.net.*; s`:>"1\|  
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public class SiteFileFetch extends Thread { _.Ey_K_1  
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SiteInfoBean siteInfoBean = null; //文件信息Bean zvvF9  
long[] nStartPos; //开始位置 *6Ojv- G|5  
long[] nEndPos; //结束位置 Cfizh@<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象
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long nFileLength; //文件长度
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boolean bFirst = true; //是否第一次取文件 aY/msplC  
boolean bStop = false; //停止标志 {i:5XL   
File tmpFile; //文件下载的临时信息 &}TfJ=gj  
DataOutputStream output; //输出到文件的输出流 k>W5ts2+  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） $jLJ&R=?]  
public SiteFileFetch(SiteInfoBean bean) throws IOException M"q]jeaM  
{ =44hI86  
siteInfoBean = bean; vcsrI8+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2>Uy`B|f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); FQV]/  
if(tmpFile.exists ()) L&C<-BA/  
{ `5y+3v~"  
bFirst = false; /(
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read_nPos(); t>04nN_@,s  
} M?61g(  
else [1I>Bc&o*  
{ (
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nStartPos = new long[bean.getNSplitter()]; QuJ~h}k  
nEndPos = new long[bean.getNSplitter()]; n@3(bl
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} XIv{jzgF  
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} 1P"akc  
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public void run() 'rT@r:6fn  
{ 1QfOD-lv  
//获得文件长度 &4aY5y`8+f  
//分割文件 FTB@70  
//实例FileSplitterFetch hq5=>p  
//启动FileSplitterFetch线程 pq \M;&  
//等待子线程返回 /0w?"2-  
try{ fz)i9D@  
if(bFirst) Bld%d:i  
{ Jk
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nFileLength = getFileSize(); <Pg]V:=g'  
if(nFileLength == -1) \ 2Jr(?U  
{ x]({Po4  
System.err.println("File Length is not known!"); oXCZpS  
} Tum9Xa  
else if(nFileLength == -2) %-zAV*>  
{ 8vN}v3HV&  
System.err.println("File is not access!"); 9*?H/iN@p?  
} T<p,KqH  
else 0ba
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{ aLwd#/!  
for(int i=0;i<nStartPos.length;i++) A+JM* eB  
{ p[Z'Fl  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); nN|zEw]  
} ?W
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for(int i=0;i<nEndPos.length-1;i++) e/;1<5tfj  
{ GJ>vL  
nEndPos = nStartPos[i+1]; X%+FM]  
} /o<tmK_m  
nEndPos[nEndPos.length-1] = nFileLength; +6vm4(3?  
} PB !\r}Q  
} 'o2V}L'nG  
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//启动子线程 4<`x*8` ,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fo"dX4%}  
for(int i=0;i<nStartPos.length;i++) _IAvFJI  
{ S9sFC!s1g  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R5QSf+/T4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "s']@Qv  
nStartPos,nEndPos,i); u8Ul +u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |?c v5l7E  
fileSplitterFetch.start(); &} b'cO  
} !_+LmBd G  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %ZV a{Nc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); kcH?l  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",  (-
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nEndPos = " + nFileLength); NT~L=xsY  
// fileSplitterFetch[nPos.length-1].start(); W\{gBjfE  
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t I9$m[  
//等待子线程结束 AT^?PD_  
//int count = 0; &i`\`6
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//是否结束while循环 e+"rL]  
boolean breakWhile = false; Dk#$PjcRE  
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while(!bStop) cw3JSz9  
{ =,D3e+P'  
write_nPos(); jWb;Xk4  
Utility.sleep(500); 8aw'
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breakWhile = true; <De29'},y  
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for(int i=0;i<nStartPos.length;i++) *Z7W'-  
{ thk33ss:  
if(!fileSplitterFetch.bDownOver) CtbmX)vE  
{ a;p3M
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breakWhile = false; LC5NB{b\%>  
break; $CaF"5}?Ke  
} 6MfjB@  
} ;4nz'9+  
if(breakWhile) EthnI7Y  
break; clz6;P  
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//count++; +{ QyB  
//if(count>4) umXa  
// siteStop(); g/+P]c6/  
} 8UB-(~  
sL;qC\S  
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System.err.println("文件下载结束！"); Bb];qYuCO  
} .bbl-a/ 3  
catch(Exception e){e.printStackTrace ();} BH0@WG7F  
} \AOVdnM:  
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//获得文件长度 m#+0uZm(  
public long getFileSize() <`EZ^S L;  
{ %&bO+$H3  
int nFileLength = -1; F9q<MTh  
try{ &1:xY.Zs_  
URL url = new URL(siteInfoBean.getSSiteURL()); u"-q"0
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *]
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httpConnection.setRequestProperty("User-Agent","NetFox"); X)d7y  
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int responseCode=httpConnection.getResponseCode(); H kDT14 `&  
if(responseCode>=400) >\hu1C|W  
{ W:{1R&$l  
processErrorCode(responseCode); = >)S\Dfi  
return -2; //-2 represent access is error ;4of7d  
} kS[xwbE  
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String sHeader; C|c'V-f  
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for(int i=1;;i++) D0,U2d  
{ &eq>>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); v\ggFrG]  
//Utility.log(in.readLine()); m4(
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sHeader=httpConnection.getHeaderFieldKey(i); '7Dg+a^x7  
if(sHeader!=null) +DS_'Tmr  
{ epi{Ayb  
if(sHeader.equals("Content-Length")) msS5"Qr  
{ A?8f 6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); WE\912j  
break; D`3m%O(?  
} {:c*-+?  
} P6*IR|  
else yhQv $D,^f  
break; b|t` )BF  
} t{tcy$bw  
} 9mkt.>$  
catch(IOException e){e.printStackTrace ();} po+>83/!oq  
catch(Exception e){e.printStackTrace ();} HjKj.f
V  
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Utility.log(nFileLength); 'mj0+c$  
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return nFileLength; hZ!N8nWwNR  
} >5)E\4r-  
]+Yd#<j(u  
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//保存下载信息（文件指针位置） hZ-No  
private void write_nPos() UOH2I+@V  
{ r-'(_t~FT  
try{ Iq.*2aff+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0V ,R|Ln  
output.writeInt(nStartPos.length); /\_`Pkd3m  
for(int i=0;i<nStartPos.length;i++) -:
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{ N~g@  
// output.writeLong(nPos); t8 g^W K  
output.writeLong(fileSplitterFetch.nStartPos); hv te)  
output.writeLong(fileSplitterFetch.nEndPos); ,%e.nj9  
} s QfP8}U  
output.close(); .T?9-`I9  
} *A.E?9pL\  
catch(IOException e){e.printStackTrace ();} HcwqVU  
catch(Exception e){e.printStackTrace ();} TO.?h!  
}
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//读取保存的下载信息（文件指针位置） eAS~>|N#x  
private void read_nPos() ECqcK~h#E  
{ Y!* \=h6h  
try{ J2 {?P cs  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A~&Tp  
int nCount = input.readInt(); "jly[M}C  
nStartPos = new long[nCount]; 5$0@f`sj  
nEndPos = new long[nCount]; H2`aw3  
for(int i=0;i<nStartPos.length;i++) xM}lX(V!w  
{ vs;T}'O  
nStartPos = input.readLong(); (D F{l?4x-  
nEndPos = input.readLong(); Fp..Sjh 6  
} `sOCJ|rc5  
input.close(); !q;EC`i#  
} %YLdie6c  
catch(IOException e){e.printStackTrace ();} J4!Om&\@  
catch(Exception e){e.printStackTrace ();} E]V:@/(M'  
} &S9Sl  
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private void processErrorCode(int nErrorCode) j+NOT`&  
{ ((F[]<?  
System.err.println("Error Code : " + nErrorCode); 1?sR1du,  
} hK*:pf  
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//停止文件下载 Lw<?e;  
public void siteStop() w
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{ %4
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bStop = true; <<!XWV*m  
for(int i=0;i<nStartPos.length;i++) pJ-/"Q|:i  
fileSplitterFetch.splitterStop(); z(L
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} }6b=2Z}  
} ;*ebq'D([  
//负责部分文件的抓取 U,S&"`a  
**FileSplitterFetch.java :{?8rA5  
*/ cN_e0;*Ua  
package NetFox; \xJTsdd  
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import java.io.*; fl>*>)6pm  
import java.net.*; 2 >G"A  
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public class FileSplitterFetch extends Thread { ?XO$9J  
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String sURL; //File URL :[P>e ox  
long nStartPos; //File Snippet Start Position {` Bgxejf  
long nEndPos; //File Snippet End Position ZOvMA]Rf  
int nThreadID; //Thread's ID ^;4nHH7z-,  
boolean bDownOver = false; //Downing is over Ex^|[iV  
boolean bStop = false; //Stop identical Yoi4R{9c  
FileAccessI fileAccessI = null; //File Access interface 6n37R#(  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException e 5U<nf  
{ ;=.VKW%U  
this.sURL = sURL; E&r*[;$  
this.nStartPos = nStart; e#]=-^  
this.nEndPos = nEnd; ](c[D9I!8  
nThreadID = id; SOQm>\U'i  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8 St`,Tq)  
} +Z[(s!  
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public void run() P[-2^1P
"  
{ 5\/h3i"I  
while(nStartPos < nEndPos && !bStop) Ym6zNb8 bQ  
{ uV?[eiezD0  
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try{ E8#r<=(m  
URL url = new URL(sURL);
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (:W=8G,p  
httpConnection.setRequestProperty("User-Agent","NetFox"); -N+'+  
String sProperty = "bytes="+nStartPos+"-"; w.exLC  
httpConnection.setRequestProperty("RANGE",sProperty); v{9< ATi  
Utility.log(sProperty); C(7
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InputStream input = httpConnection.getInputStream(); Q)x`'[3"7W  
//logResponseHead(httpConnection); ^pA|ubZ  
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byte[] b = new byte[1024]; i_T8Bfd:  
int nRead; J@'}lG  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )P>Cxzs  
{ oyV@BHJO@  
nStartPos += fileAccessI.write(b,0,nRead); m5Gt8Z 6a  
//if(nThreadID == 1) #UGm/4C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RkP g&R;i  
} 7KU/ 1l9$9  
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Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; 1MV\Jm  
//nPos = fileAccessI.write (b,0,nRead); ilL] pU
-  
} 1
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catch(Exception e){e.printStackTrace ();} @A6P[r  
} X&EcQ  
} o(5Xj$Z  
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//打印回应的头信息 $'!r/jV  
public void logResponseHead(HttpURLConnection con) Z'iXuI49  
{ Bgs3sM9  
for(int i=1;;i++) }I_/>58  
{ `ZL~k  
String header=con.getHeaderFieldKey(i); ;\yY*  
if(header!=null) > E
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); Wi]Mp7b  
Utility.log(header+" : "+con.getHeaderField(header)); ]0<T,m Z  
else sLh9=Kh`  
break; BhC.#u/   
} 6u^MfOc  
} rxtp?|v9  
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public void splitterStop() <wV?B9j  
{ ]F kLtq  
bStop = true; dX
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} \5.36Se  
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} 7A@GNA  
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/* o#Q0J17i?  
**FileAccess.java >]uV  
*//文件访问(定位，写) |~vo  
package NetFox; 1?s]nU  
import java.io.*; 6FuZMasr*  
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public class FileAccessI implements Serializable{ "{-jZdq'  
*{|{T_H:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 mk#xbvvG  
RandomAccessFile oSavedFile; W]cJP  
long nPos; lrg3n[y-l  
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public FileAccessI() throws IOException o>lk+Q#L @  
{ pj?wQ'  
this("",0); wRu+:<o^.  
} R5=2EwrGP  
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public FileAccessI(String sName,long nPos) throws IOException 5*QNE!  
{ w yi n  
oSavedFile = new RandomAccessFile(sName,"rw"); _(=[d  
this.nPos = nPos; w_o|k&~,  
oSavedFile.seek(nPos); M_@%*y\o  
} --*Jv"/0  
t,|`#
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public synchronized int write(byte[] b,int nStart,int nLen)
]A)`I  
{ kGbtZ} W  
int n = -1; d%tF~|#A%  
try{ K^0cL%dB  
oSavedFile.write(b,nStart,nLen); KICy! "af  
n = nLen; wWV`k  
} oGz-lO{lt  
catch(IOException e) b?Dhhf  
{ =?fxPT[1K  
e.printStackTrace (); r9[{0y!4  
} (
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return n; FJ]BB4 K  
} 6^ UQ{P1;  
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} U1zcJl^  
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/* `uL^!-  
**SiteInfoBean.java ~Y=v@] 2/  
*/ ];cJIa  
package NetFox; + ;u<tA  
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public class SiteInfoBean { daamP$h9  
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private String sSiteURL; //Site's URL C4vmgl&  
private String sFilePath; //Saved File's Path 3|1ug92  
private String sFileName; //Saved File's Name *fs'%"w-  
private int nSplitter; //Count of Splited Downloading File dUAZDoLi  
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public SiteInfoBean() 7RW5U'B  
{//nSplitter的缺省值为5 Ww8<f$  
//default value of nSplitter is 5 %mLQ'$  
this("","","",5); bvVEV  
} dg#w/}}m  
3/+r*lv>X  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ')]K&  
{ NCm>iEeY  
sSiteURL= sURL; xw2dEvjgp%  
sFilePath = sPath; jhs('n,  
sFileName = sName; N>8pA)  
this.nSplitter = nSpiltter; Z4+S4cqnh  
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} VRr_s:CWK  
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public String getSSiteURL() \^=Wp'5R  
{ or2BG&W  
return sSiteURL; X~ca8!Dq  
} 6|#+  
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public void setSSiteURL(String value) k[6%+  
{ i-6,r[<  
sSiteURL = value; P<&-8QA  
} i7@qfe$fR  
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public String getSFilePath() 8^/V2;~^,>  
{ V4c$V]7  
return sFilePath; cRt[{HE  
} )"Ef* /+  
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public void setSFilePath(String value) <Uz~V;  
{ *Ru@F:  
sFilePath = value; IP)?dnwG  
} ^;on  
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public String getSFileName() 9wR-0E )  
{ vkFfHzR$  
return sFileName; Ww(($e!  
} @|yRo8|  
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public void setSFileName(String value) .QwwGm  
{ g~zz[F 8U  
sFileName = value; z&a%_ ]Q*  
} !rmXeN]-r  
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public int getNSplitter() \\<waU''  
{ `jl 1Q,~2r  
return nSplitter; irqNnnMGEa  
} cQ:Y@f 9  
d
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public void setNSplitter(int nCount) -c%K_2`  
{ )9(Mt_  
nSplitter = nCount; v=-8} S  
} |
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} -Oj}PGj$e\  
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Z^Y_+)
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/* +4[L_  
**Utility.java #2N']VP  
*/ 2&L2G'  
package NetFox; ~g&Fe
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public class Utility { aSu6SU  
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public Utility() cmw2EHTT<  
{ VBHDI{HzRv  
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} `RRC8]l  
#LP38wE  
//线程睡眠 KY1(yni&8[  
public static void sleep(int nSecond) D%tcYI(  
{ aT v  
try{ XynDo^+ru  
Thread.sleep(nSecond); {9yv3[f3  
} @-uV6X8|  
catch(Exception e) )3
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{ XiP xg[;  
e.printStackTrace (); ]h]|PdN  
} fSe$
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} /}%$fB  
-\Y"MwIED  
//日志 DK!QGATh  
public static void log(String sMsg) j3<|
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{ (}$pf6s  
System.err.println(sMsg); 
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} 2`D1cX  
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public static void log(int sMsg) RyI(6TZl  
{ Gp0B^^H$  
System.err.println(sMsg); zQ;jaS3hf  
} AKKp-I5  
} jm|x=s3}h  
--(e(tvf  
jgc
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/* \v7->Sy8  
**TestMethod.java 6qCRM*V  
*/ .@#GNZe  
package NetFox; %Tc P[<  
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f  
;7Hse^Oc  
public class TestMethod { d0@&2hO  
=}bDT2Nb  
jRk"#:  
public TestMethod() m :6.  
{ ///xx/weblogic60b2_win.exe J(k\Pz*  
try{ Ts+S>$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); l%$~X0%DM  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +[ +4h}?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3M5+!H  
fileFetch.start(); YQ\c0XG  
} DEdJH4  
catch(Exception e){e.printStackTrace ();} J}$St|1y  
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} 15o<'4|=Lm  
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public static void main(String[] args) *bi!iz5F  
{ *.4VO+^  
new TestMethod(); &, =Z  
} COV8=E~  
} MF7q*f  
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