http断点续传简单实现（java)

/* dRDnJc3  
**SiteFileFetch.java o}!PQ#`M  
*/ cu6Opq9  
package NetFox; DrQ`]]jj7  
import java.io.*; /E>e"tvss  
import java.net.*; [!z,lY>  
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public class SiteFileFetch extends Thread { P%zK;#8V  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 1"g<0 W  
long[] nStartPos; //开始位置 >V~E]P%@  
long[] nEndPos; //结束位置 Lv%x81]K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 26nx`w?j(  
long nFileLength; //文件长度 $C\BcKlmv  
boolean bFirst = true; //是否第一次取文件 :%.D78&  
boolean bStop = false; //停止标志 ?8$Q-1=  
File tmpFile; //文件下载的临时信息 MJvp6n  
DataOutputStream output; //输出到文件的输出流 Vc2`b3"Br  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） nwWJ7M,A  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3u;oQ5<(v  
{ =}*0-\QG  
siteInfoBean = bean; <qSC#[xu  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Dj+f
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3Y &d=  
if(tmpFile.exists ()) 1qch]1 ^G  
{ 0mnw{fE8_  
bFirst = false; ]! dTG  
read_nPos(); / +\9S  
} w@b)g  
else (?c-iKGc  
{ OH88n69  
nStartPos = new long[bean.getNSplitter()]; ~V-XEQA  
nEndPos = new long[bean.getNSplitter()]; +H.`MZ=  
} FtZ?C@1/  
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} q@&6#B  
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public void run() g*Ph
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{ '7/)Ot(  
//获得文件长度 B6"0OIDY"  
//分割文件 _+,TT['57s  
//实例FileSplitterFetch `gJ(0#ac  
//启动FileSplitterFetch线程
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//等待子线程返回 ?`#Khff?  
try{ y*? Jui Q  
if(bFirst) nEfK53i_  
{ <[v[ci  
nFileLength = getFileSize(); q<J~~'  
if(nFileLength == -1) Nl/dX-I  
{ ]yu:i-SfP  
System.err.println("File Length is not known!"); \lY_~*J  
} 4JE
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else if(nFileLength == -2) pJ=#zsE0  
{ ;*N5Y}?j'  
System.err.println("File is not access!"); ),)lzN%!  
} <GJbmRc|  
else m[$_7a5  
{ #ABCDi={zA  
for(int i=0;i<nStartPos.length;i++) 2/f}S?@   
{ ; KA~Z5x;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *#2h/
Q.  
} j+!v}*I![  
for(int i=0;i<nEndPos.length-1;i++) omFz@  
{ @7u0v  
nEndPos = nStartPos[i+1]; [m -bV$-d  
} \GBuWY3B  
nEndPos[nEndPos.length-1] = nFileLength; [RL9>n8f  
} S@Y39  
} 83m3OD_y  
~>G^=0LT  
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//启动子线程 +_`7G^U?%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vIvIfE  
for(int i=0;i<nStartPos.length;i++) Y@v>FlqI{  
{ YQ}o?Q$z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H+#FSdy#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), t7pFW^&  
nStartPos,nEndPos,i); C^){.UGmJ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /}$+uBgJm  
fileSplitterFetch.start(); hb-%_c"kq  
} gIfh3D=yX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uO**E-`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); DH=hH&[e(d  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", FwK]$4*  
nEndPos = " + nFileLength); [ )F<V!  
// fileSplitterFetch[nPos.length-1].start(); N#]ypl  
f^e)O$N9]  
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//等待子线程结束 7=uj2.J6  
//int count = 0; JT?h1v<H]  
//是否结束while循环 zCA2X !7F  
boolean breakWhile = false; [Pp'Ye~K@c  
J4'eI[73  
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while(!bStop) yauvXosX  
{ [UR-I0 s!/  
write_nPos(); @iiT
<
 
Utility.sleep(500); /1 dT+>  
breakWhile = true; ^ 9sjj  
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for(int i=0;i<nStartPos.length;i++) ^q&x7Kv%  
{ K"6vXv4QO  
if(!fileSplitterFetch.bDownOver) iscz}E,Y  
{ `V1]k_h  
breakWhile = false; sA~]$A;DM!  
break; Sdo-nt  
} Ef\-VKh  
} mDWG7Asp  
if(breakWhile) i%/+5gq  
break; x;S @bY  
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//count++; &m3lXl  
//if(count>4) kM6 Qp  
// siteStop(); ?< />Z)
  
} 3Vwh|1?  
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System.err.println("文件下载结束！"); }k0_5S  
} J,hCvm  
catch(Exception e){e.printStackTrace ();} mw!F{pw  
} '91/md5  
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#spCtZE  
//获得文件长度 | Iib|HQ)  
public long getFileSize() ^~dWU>  
{ ]d]]'Hk  
int nFileLength = -1; dM5-;  
try{ Q8NX)R  
URL url = new URL(siteInfoBean.getSSiteURL()); e(sk[guvX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bOB\--:]  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7/H)Az@i45  
uH]OEz\H'  
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int responseCode=httpConnection.getResponseCode(); !VJoM,b8  
if(responseCode>=400) pRqx`5 }  
{ ixFi{_  
processErrorCode(responseCode); .8R@2c`}Cs  
return -2; //-2 represent access is error m*pJBZxd  
} w(/S?d  
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String sHeader; YVU7wW,1  
3Ul*QN{6  
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for(int i=1;;i++) 3<!7>]A  
{ n]9$:aLZ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]'}L 1r  
//Utility.log(in.readLine()); )UR7i8]!0  
sHeader=httpConnection.getHeaderFieldKey(i); QY/w  
if(sHeader!=null) E.TAbD&5(  
{ ,2q-D&)\Z  
if(sHeader.equals("Content-Length")) }pYqWTG  
{ tc! #wd+u  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); uYN`:b8  
break; l;Wj]  
} 'NmRR]Q9  
} ~a:  
else Oz95  
break; NOva'qk  
} /7kC<  
} p'%s=TGwv  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} ]/Pn EU[  
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Utility.log(nFileLength); siI;"?  
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return nFileLength; *pq\MiD/  
} QV!up^Zso  
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//保存下载信息（文件指针位置） r;{.%s7  
private void write_nPos() RP"kC4~1  
{ aOp\91  
try{ wT@og|M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); d-qUtgqV86  
output.writeInt(nStartPos.length); b9krOe*j  
for(int i=0;i<nStartPos.length;i++) S'" Df5  
{ 6Oq7#3]  
// output.writeLong(nPos); UN
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output.writeLong(fileSplitterFetch.nStartPos); CTb%(<r  
output.writeLong(fileSplitterFetch.nEndPos); (zk"~Ud  
} oU8q o-J1H  
output.close(); @]j1:PN-  
} A"]YM'.  
catch(IOException e){e.printStackTrace ();} rp$'L7lrX  
catch(Exception e){e.printStackTrace ();} V`- 9m$  
} !g[Zfo2r"  
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//读取保存的下载信息（文件指针位置） *w&e\i|7  
private void read_nPos() x:Y1P:  
{ 4dlGxat  
try{ Hs8>anVo[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &
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int nCount = input.readInt(); V!
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nStartPos = new long[nCount]; TOt dUO  
nEndPos = new long[nCount]; & 21%zPm  
for(int i=0;i<nStartPos.length;i++) e+WNk 2  
{ }#fbbtd  
nStartPos = input.readLong(); ]M=&+c>H~  
nEndPos = input.readLong(); aN?zmkPpov  
} /: "1Z]@  
input.close(); a(nlTMfu  
} dd;~K&_Q/i  
catch(IOException e){e.printStackTrace ();} W1~0_;  
catch(Exception e){e.printStackTrace ();} zCZf%ATq  
} :Ye !w$r  
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e ,(mR+a8  
private void processErrorCode(int nErrorCode) **%37  
{ kVgTGC"L=  
System.err.println("Error Code : " + nErrorCode); "jZ-,P=  
} 3fj4%P"  
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//停止文件下载 ?s01@f#  
public void siteStop() [,Gg^*umS  
{ (QEG4&9  
bStop = true; +7Gwg  
for(int i=0;i<nStartPos.length;i++) @ Y+oiB~Y  
fileSplitterFetch.splitterStop(); -w2/w@&  
J1k>07}
|  
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} D*jM1w_`  
} pi(m7Ci"  
//负责部分文件的抓取 Sjqpec8  
**FileSplitterFetch.java 9[4xFE?|  
*/ Wr 4,YQM  
package NetFox; XFl6M~ c  
>MZ/|`[M  
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import java.io.*; <'u'#E@"sl  
import java.net.*; X'ag)|5ot  
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public class FileSplitterFetch extends Thread { IGl9g_18  
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String sURL; //File URL BmT!aue  
long nStartPos; //File Snippet Start Position i!Ba]n   
long nEndPos; //File Snippet End Position Gc?a+T  
int nThreadID; //Thread's ID _BufO7`.  
boolean bDownOver = false; //Downing is over K(4_a``05  
boolean bStop = false; //Stop identical 5BIY<B+i  
FileAccessI fileAccessI = null; //File Access interface L(-4w+  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6ujWNf  
{ m67V_s,7B  
this.sURL = sURL; 10&8-p1/mc  
this.nStartPos = nStart; [^iN}Lz  
this.nEndPos = nEnd; hrk r'3lv  
nThreadID = id; wYea\^co  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  mh%VrAq  
} z{q`GwW  

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public void run() *. t^MP  
{ W?&%x(6M  
while(nStartPos < nEndPos && !bStop) tQVVhXQ7  
{ ^iA9%zp  
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try{ *~`(RV  
URL url = new URL(sURL); h[ ZN+M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i8p6Xht  
httpConnection.setRequestProperty("User-Agent","NetFox"); jXJyc'm7  
String sProperty = "bytes="+nStartPos+"-"; 6BlXLQ,8q  
httpConnection.setRequestProperty("RANGE",sProperty); JF]JOI6.e  
Utility.log(sProperty); sOY:e/_F  
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InputStream input = httpConnection.getInputStream(); btB%[]  
//logResponseHead(httpConnection); \U0Q<ot/7  
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byte[] b = new byte[1024]; 'u658Tj  
int nRead; Om&Dw|xG8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /Oono6j  
{ Ri'n  
nStartPos += fileAccessI.write(b,0,nRead); ]~-r}`]  
//if(nThreadID == 1) @EAbF>>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P>T"cv  
} NK+o1  
KvSG;  
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Utility.log("Thread " + nThreadID + " is over!"); K3C<{#r  
bDownOver = true; 1C.VnzRnJ  
//nPos = fileAccessI.write (b,0,nRead); :UdF  
} }Z>)DN=+  
catch(Exception e){e.printStackTrace ();} `oJ [u:b  
} K
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} pAEx#ck  
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*Ex|9FCt$  
//打印回应的头信息 1YA% -~  
public void logResponseHead(HttpURLConnection con) ;S{(]K7i  
{ '-6~tWC~7  
for(int i=1;;i++) U*:!W=XN  
{ iLT}oKF2N;  
String header=con.getHeaderFieldKey(i); 9mgIUjz  
if(header!=null) ^Cmyx
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); $>gFf}#C  
Utility.log(header+" : "+con.getHeaderField(header)); E^PB)D(.  
else eyaNs{TV  
break; oU|c
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} |qLh5Ty  
} =41xkAMnk  
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public void splitterStop() !k%#R4*>  
{ q4q6c")zp  
bStop = true; VQI3G  
} K,]=6Rj  
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)[ ,A_3E  
} g0 [w-?f  
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/*
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**FileAccess.java wBzC5T%,  
*//文件访问(定位，写) 67TwPvh  
package NetFox; >/\'zi]L  
import java.io.*; Si,6o!0k  
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public class FileAccessI implements Serializable{ h![#;>(  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 P2!C|SLK  
RandomAccessFile oSavedFile; zX~MC?,W1  
long nPos; l,:F  
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public FileAccessI() throws IOException )+M0Y_r  
{ hSMH,^Io$  
this("",0); [Q =Nn  
} "3hMq1NQ`g  
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public FileAccessI(String sName,long nPos) throws IOException }Lv;

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{ 2tLJU Z1  
oSavedFile = new RandomAccessFile(sName,"rw"); eQ"E  
this.nPos = nPos; h~26WLf.  
oSavedFile.seek(nPos); N7_"H>O$0U  
} S$3JMFA  
:KN-F86i  
7.T?#;'3  
public synchronized int write(byte[] b,int nStart,int nLen) 1cGmg1U;  
{ :LTN!jj  
int n = -1; KG@8RtHsQ  
try{ 8f7>?BUS,  
oSavedFile.write(b,nStart,nLen); G j1_!.T  
n = nLen; ;
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} C7vxw-o|&p  
catch(IOException e) !c-*O<Y  
{ Zov~B-Of:  
e.printStackTrace (); ,47qw0=C  
} &R siVBA  
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return n; 2Hdu:"j  
} ]d`VT)~vje  
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} e%6QTg5#  
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/* 6Iw\c  
**SiteInfoBean.java
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*/  9akH  
package NetFox; |M_UQQAB|  
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public class SiteInfoBean { KF/-wZ"1s  
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private String sSiteURL; //Site's URL >{Tm##@,k  
private String sFilePath; //Saved File's Path )jC%a6G!  
private String sFileName; //Saved File's Name 0g\(+Qg^  
private int nSplitter; //Count of Splited Downloading File [r-p]"R  
1sCR4L:+  
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public SiteInfoBean() -![|}p
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{//nSplitter的缺省值为5 +*^H#|!  
//default value of nSplitter is 5 }-fl$j?9E  
this("","","",5); 'n|5ZhXPB  
}
6^Sa;  
 XlJZhc  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) - YV>j  
{ .mAjfP*  
sSiteURL= sURL; }&e5$lB  
sFilePath = sPath; y==CTY@  
sFileName = sName; $SE^S  
this.nSplitter = nSpiltter; 1.X@;  
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} xm@_IL&P  
O~QB!<Q+  
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public String getSSiteURL() g1o8._f.  
{ 3,=6@U  
return sSiteURL; $g7<Y*t[  
} !a<ng&H^U  
H.2QKws^F  
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public void setSSiteURL(String value) '{`$#@a.  
{ Wm3X[?V  
sSiteURL = value; R$Q.sE  
} p$>l7?h  
@o6L6Y0Naa  
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public String getSFilePath() A9JdU&  
{ }T$p)"  
return sFilePath; f {"?%Ku#  
} 0LKRN|@  
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public void setSFilePath(String value) "Pf~iwfw  
{ PuO&wI]:  
sFilePath = value; hL5|69E  
} L:
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IMfqiH)  
)/EO&F  
public String getSFileName() 'ah[(F<*@e  
{ \G3rX9xG  
return sFileName; X|8c>_}  
} m9A
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Bw{I;rW{2  
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public void setSFileName(String value) 9M9?%N:ra  
{ ]cN1c}  
sFileName = value; ~=
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} F3N6{ysK#  
d:{O\   
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public int getNSplitter() AvHCO8h|  
{ @gtQQxf"  
return nSplitter; pBPl6%C.X-  
} !3v1bGk  
2"S}bfrX  
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public void setNSplitter(int nCount) N&V`K0FU  
{ g>9kXP+  
nSplitter = nCount; d'I"jZ  
} w'3iY,_ufC  
} -S+zmo8  
{u9}bx'<  
M:6"H%h,W  
/* I0RvnMw  
**Utility.java KK%M~Y+tU'  
*/ TBrPf-Xr  
package NetFox; Fr$5RAyg  
jZ3fKyp#
 
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public class Utility { 1>&]R=  
O,A{3DAe0  
~3S~\0&|  
public Utility() 4 N7^?  
{ eNu7~3k}  
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} .y,0[i V N  
~| 6[j<ziL  
//线程睡眠 lUiL\~Gq  
public static void sleep(int nSecond) D#/Bx[  
{ [ps*uva  
try{ @oad,=R&  
Thread.sleep(nSecond); 0nD/;\OU  
} tlt*fH$.  
catch(Exception e) o7LuKRl   
{ o\)F}j&b#=  
e.printStackTrace (); 9 5RBO4w%w  
} f0aKlhEC  
} bD8Gwi=iiu  
P_#bow  
//日志 l?^4!&Nm  
public static void log(String sMsg) @k/NY*+  
{ g SAt@2*U2  
System.err.println(sMsg); AZ}Xj>=  
} Bng@-#`/  
yEj^=pw  
`I5wV/%ib  
public static void log(int sMsg) [,KXze_m  
{ (DP &B%Sf  
System.err.println(sMsg); \K<QmK  
} a+T.^koY  
} K>l~SDcZ3  
78H'ax9m  
yqiq,=OvP  
/* qc~iQSI  
**TestMethod.java U2~kJ  
*/ *``JamnSO  
package NetFox; Q({ r@*g  
m<q
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public class TestMethod { y%bF&  
h.s+)fl\  
S+^E.  
public TestMethod() (41|'eB\\  
{ ///xx/weblogic60b2_win.exe ^UhBH@ti  
try{ JO"<{ngsQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); DXK}-4"\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Wh2tNyS  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v+=BCyT  
fileFetch.start(); x*&|0n.D  
} Ziu]'#  
catch(Exception e){e.printStackTrace ();} nSAdCJ;4  
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} A4<Uu~  
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public static void main(String[] args) ;H.^i|_/  
{ -701j'q{  
new TestMethod(); GU8sO@S5#  
} !V g`  
} @Sbe^x  
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