http断点续传简单实现（java)

/* mdmvT~`  
**SiteFileFetch.java BJB^m|b)  
*/ 57zSu3v4Y  
package NetFox; v~V5`%  
import java.io.*; E^lvbLh'  
import java.net.*; W<$Z=(_v  
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public class SiteFileFetch extends Thread { iZNts%Y]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean X;B\Kj`n  
long[] nStartPos; //开始位置 sCis4gX.]  
long[] nEndPos; //结束位置 %Bn?n{/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \h DdU+  
long nFileLength; //文件长度 #Jn_c0  
boolean bFirst = true; //是否第一次取文件 *-q"3D`  
boolean bStop = false; //停止标志 xA1hfe.9  
File tmpFile; //文件下载的临时信息 ,TPISs  
DataOutputStream output; //输出到文件的输出流 L%K\C  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） , GY h9  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]2'na?q9  
{ #u"k~La  
siteInfoBean = bean; f3{MvAy[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); vj\dA2!~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); YZ7|K<   
if(tmpFile.exists ()) zG9Y!
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{ AvSM^  
bFirst = false; Zh*u(rO  
read_nPos(); ?)[EO(D  
} !Mim@!5M  
else [y)`k@  
{ T[4<R 5}  
nStartPos = new long[bean.getNSplitter()]; {]_r W/  
nEndPos = new long[bean.getNSplitter()]; '+vA\(K  
} UkHY[M7;  
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} C,NxE5?h  
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public void run() OY5OJ*  
{ }kK[S|XVO  
//获得文件长度 f0<%&2ym  
//分割文件 <~!Hx+j   
//实例FileSplitterFetch bi&*9K0  
//启动FileSplitterFetch线程 s^|.Zr;,>  
//等待子线程返回 3=$q  
try{ b0A1hb[|  
if(bFirst) ]f: v,a  
{ J}@z_^|"mJ  
nFileLength = getFileSize(); ~$f;U  
if(nFileLength == -1) jfx8EbQ  
{ =w5O&(  
System.err.println("File Length is not known!"); M$d%p6Cv  
} NeBsv= [-  
else if(nFileLength == -2) OXi@c;F  
{ drd/jH&  
System.err.println("File is not access!"); 4)4+M  
} ^1x*lLf  
else UMp/
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{ 7Wa?$6d  
for(int i=0;i<nStartPos.length;i++) HCJ>X;(`f?  
{ iQ6epg1wB  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); G,<T/f .{$  
} z%7SrUj2  
for(int i=0;i<nEndPos.length-1;i++)  ^eGNgE  
{ [kzd(u  
nEndPos = nStartPos[i+1]; 9cx =
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} sv(f;ib  
nEndPos[nEndPos.length-1] = nFileLength;
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} JwRF(1_sM  
} ?D)<,  
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//启动子线程 %Lrd6i_j  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; N+)?$[  
for(int i=0;i<nStartPos.length;i++) ,j ',x\  
{ <{:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <0.$'M~E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bo=ZM9  
nStartPos,nEndPos,i); e{9jn>\,a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A[dvEb;r  
fileSplitterFetch.start(); H{
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} lhYn5d)DV  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !epgTN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #Hh^3N  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", asgF1?r  
nEndPos = " + nFileLength); tPyyZ#,  
// fileSplitterFetch[nPos.length-1].start(); zT* .jv  
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//等待子线程结束 x/
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//int count = 0; ;C/bJEgdd  
//是否结束while循环 PS" .R
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boolean breakWhile = false; ]43bere  
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while(!bStop) l n}}5Q  
{ tAFti+Qb  
write_nPos(); 5NXt$k5  
Utility.sleep(500); {,j6\Cj4  
breakWhile = true; j#6|V]l  
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for(int i=0;i<nStartPos.length;i++) kao}(?x%  
{ Y/8K;U|  
if(!fileSplitterFetch.bDownOver) r\9TMg`C  
{ I5);jgb  
breakWhile = false; &yz&LNn'  
break; q1hMmMi  
} pY^9l3y^  
} <<|H=![  
if(breakWhile) 7TX,T|>9  
break; #S+Z$DQD  
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//count++; 9-bG<`v\E  
//if(count>4) .Nx W=79t  
// siteStop(); mf|pNiQ,  
} r<L#q)]  
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System.err.println("文件下载结束！"); JK~ m(oQ  
} ~j@UlP  
catch(Exception e){e.printStackTrace ();} bn 4 &O  
} Hr
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//获得文件长度 KLt%[$CTi  
public long getFileSize() "g
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{ {%']w  
int nFileLength = -1; VZA3IbK}  
try{ ]~a_d)  
URL url = new URL(siteInfoBean.getSSiteURL()); ?Nl"sVCo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eZO9GMO  
httpConnection.setRequestProperty("User-Agent","NetFox"); cvAtwQ'  
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int responseCode=httpConnection.getResponseCode(); e.6Dl_  
if(responseCode>=400) (@ea|Fd#4  
{ J/4y|8T/y  
processErrorCode(responseCode); c%YDt`  
return -2; //-2 represent access is error It 2UfW  
} VvgN3e[  
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String sHeader; 8g5V,3_6  
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for(int i=1;;i++) T~Yg5J  
{ y-`I) w%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); C"T,MH  
//Utility.log(in.readLine()); rqvU8T7A  
sHeader=httpConnection.getHeaderFieldKey(i); .g-3e"@  
if(sHeader!=null) cy:;)E>/  
{ owMuT^x?  
if(sHeader.equals("Content-Length")) Rx. rj~  
{ I>m;G `  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); KHJ=$5r)
 
break; ^~I @ spR4  
} 1XnBK$`  
} lgG8!Ja  
else *Pb.f  
break; >1XL;)IL>  
}
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} UIw?;:Y  
catch(IOException e){e.printStackTrace ();} gLCz]D.'  
catch(Exception e){e.printStackTrace ();} *7vue"I*Z  
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Utility.log(nFileLength); fle0c^=  
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return nFileLength; vadM1c*z  
} Gt.*_E  
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//保存下载信息（文件指针位置） )9pBu B  
private void write_nPos() `hF;$  
{ 7+]F^ 6  
try{ '?L%F{g/9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); F0:
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output.writeInt(nStartPos.length); 4O Zy&,  
for(int i=0;i<nStartPos.length;i++) xfUhSt  
{ ks^|>  
// output.writeLong(nPos); IgiqFV{  
output.writeLong(fileSplitterFetch.nStartPos); bfc.rZ  
output.writeLong(fileSplitterFetch.nEndPos); fsb=8>}63}  
} $UmE  
output.close(); 1(F
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} v7$9QVze  
catch(IOException e){e.printStackTrace ();} IHfSkFz`j  
catch(Exception e){e.printStackTrace ();} ][N) 2_^M  
} f8F1~q  
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.i
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//读取保存的下载信息（文件指针位置） H!^C
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private void read_nPos() ;op'V6iG  
{ V?WMj $l<  
try{ 6A@Lj*:2m  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); v @_?iC"`  
int nCount = input.readInt(); up7x)w:  
nStartPos = new long[nCount]; z+2u-jG  
nEndPos = new long[nCount]; oYGUjI  
for(int i=0;i<nStartPos.length;i++) +"G(  
{ kt5YgW  
nStartPos = input.readLong(); |<7i|J  
nEndPos = input.readLong(); .k|-Ks|d|  
} iPJ9Gh7  
input.close(); @YbZ8Uc  
} 0I649
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catch(IOException e){e.printStackTrace ();} %!W6<ioW  
catch(Exception e){e.printStackTrace ();} 5D>BV*"  
} %G^(T%q| m  
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private void processErrorCode(int nErrorCode) (h%|;9tF  
{ =`ywd]\7  
System.err.println("Error Code : " + nErrorCode); s:G[Em1  
} U0ns3LirP  
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//停止文件下载 =54Vs8.  
public void siteStop() Ty(yh(oYF`  
{ ($,iAb  
bStop = true; RbyF#[}  
for(int i=0;i<nStartPos.length;i++) Udg& eEF  
fileSplitterFetch.splitterStop(); CiHn;-b;  

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} 6qY\7R2+  
} s-
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//负责部分文件的抓取 8dYk3sk  
**FileSplitterFetch.java T;xHIg4
 
*/ W'm!f  
package NetFox; QGu
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import java.io.*; 3/yt*cr  
import java.net.*; (bM)Nd  
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public class FileSplitterFetch extends Thread { ,7WK<0  
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String sURL; //File URL JsHxQ0Tw  
long nStartPos; //File Snippet Start Position 
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long nEndPos; //File Snippet End Position V7Vbl?*n  
int nThreadID; //Thread's ID A?^A
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boolean bDownOver = false; //Downing is over )ylv(qgV  
boolean bStop = false; //Stop identical ;Hz`0V  
FileAccessI fileAccessI = null; //File Access interface
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException d"QM;9  
{ j=!(F`/  
this.sURL = sURL; Z{8exy
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this.nStartPos = nStart; $X{B* WF  
this.nEndPos = nEnd; OtrXYiKB   
nThreadID = id; |*/uN~[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ({ :yw  
} EN5G:hD  
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public void run() P'FPe55F  
{ Y`E{E|J  
while(nStartPos < nEndPos && !bStop) >llwNT  
{ S|O%h}AH;  
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try{ v '"1/% L  
URL url = new URL(sURL); sM);gI14  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =0jmm(:Jh  
httpConnection.setRequestProperty("User-Agent","NetFox"); u(TgWp5WF  
String sProperty = "bytes="+nStartPos+"-"; ^=heen<S%  
httpConnection.setRequestProperty("RANGE",sProperty); YFC0KU  
Utility.log(sProperty); 5Xq.=/eX  
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InputStream input = httpConnection.getInputStream(); S>vVjq?~l(  
//logResponseHead(httpConnection); [E..VesrM  
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byte[] b = new byte[1024]; jN5} 2 p*  
int nRead; :"y7Weh  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) m;$F@JJ  
{ K
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nStartPos += fileAccessI.write(b,0,nRead); (<g;-pZH%  
//if(nThreadID == 1)
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f"Vm'0r  
} ?*MV ^IY  
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Utility.log("Thread " + nThreadID + " is over!"); tSh}0N)  
bDownOver = true; qKI4p3&E  
//nPos = fileAccessI.write (b,0,nRead); ,*O{jc`(  
} hBYh90]  
catch(Exception e){e.printStackTrace ();} X&;]  
} }fa%JN %E  
} L3hxe]mr  
#u]_7/(</`  
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//打印回应的头信息 .k!k-QO5La  
public void logResponseHead(HttpURLConnection con) n
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{ V+"*A  
for(int i=1;;i++) A$9_aqbj  
{ ;29XvhS8  
String header=con.getHeaderFieldKey(i); $M8>SLd  
if(header!=null) U K]{]-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); uN?O*h/(  
Utility.log(header+" : "+con.getHeaderField(header)); q[,R%6&'  
else zdpLAr  
break; l2KxZteXY0  
} >-./kI "  
} /w0v5X7  
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public void splitterStop() +ouy]b0`t  
{ /{#_Um0.  
bStop = true; 7`'fUhB!  
} *"9)a6T t+  
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} (k2J{6]  
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/* gm%bxr@X~  
**FileAccess.java k`J..f9  
*//文件访问(定位，写) KA*l6`(  
package NetFox; Gv2./<{#  
import java.io.*; "ih>T^|  
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)V =K#MCK  
public class FileAccessI implements Serializable{ r7BH{>-  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 )GT?Wd  
RandomAccessFile oSavedFile; r1H['{$  
long nPos; ;g)Fhdy!  
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public FileAccessI() throws IOException c+K=pp@  
{ k2,oyUT=S  
this("",0); $6x:aG*F  
} qYiK bzy  
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public FileAccessI(String sName,long nPos) throws IOException rZCAj  
{ tVh4v#@+  
oSavedFile = new RandomAccessFile(sName,"rw"); 6!D  
this.nPos = nPos; #yRA.;  
oSavedFile.seek(nPos); JhXN8Bq33  
} NF.6(PG|  
,(kXF:  
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public synchronized int write(byte[] b,int nStart,int nLen) }Z$G=;3#  
{ NX #d}M^V  
int n = -1; {gHscj;SM  
try{ ]f @LhC1x  
oSavedFile.write(b,nStart,nLen); nZ+5@( *  
n = nLen; yl+)I  
} 1?$!y  
catch(IOException e) `Ta(P30  
{ 7,VWvmWJex  
e.printStackTrace (); NcMq
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} 8GRrf2  
v?=VZ~`O(  
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return n; wgP3&4cSUc  
} &>B>+}'
 
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} { RX|  
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/* Zd/~ *ZA  
**SiteInfoBean.java NGZ>:  
*/ !PTbR4s  
package NetFox; :=7;P)  
A;HKR4p;8  
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public class SiteInfoBean { 4J|t}  
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private String sSiteURL; //Site's URL )@|Fh@|  
private String sFilePath; //Saved File's Path CP#MNNvgrw  
private String sFileName; //Saved File's Name d"a7{~l  
private int nSplitter; //Count of Splited Downloading File zszx@`/3  
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public SiteInfoBean() <:t\P.  
{//nSplitter的缺省值为5 )F2tV ]k\  
//default value of nSplitter is 5 ~i#xjD5  
this("","","",5); A0sW 9P6F  
} j!n> d  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <4bo7XH  
{ jM<Ihmh|  
sSiteURL= sURL; n\DT0E]  
sFilePath = sPath; oob0^}^  
sFileName = sName; ,"R_ve  
this.nSplitter = nSpiltter; NistW+{<  
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} Qt39H@c|z~  
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public String getSSiteURL() +:Zi(SuS]  
{ l'f!za0  
return sSiteURL; py4_hj\v  
} E:OeU_\  
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public void setSSiteURL(String value) 4(ZV\}j1  
{ =MLL-a1  
sSiteURL = value; [!
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} :UciFIa  
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public String getSFilePath() H:Le^WS  
{ \OH:xW~  
return sFilePath; !IU*Ayg  
} 4(IP  
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public void setSFilePath(String value) $sJfxh r  
{ n\Nl2u& m  
sFilePath = value; u9(AT>HxT  
} WRM}gWv*  
{}e IpK,+  
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public String getSFileName() h^,a 1'  
{ v_h{_b8  
return sFileName; j=4>In?x  
} ;zODp+4@Q  
,//=yW  
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public void setSFileName(String value) [8#l~ |U  
{ &9tsk#bA.g  
sFileName = value; sqRuqUj+  
} 9b6h!(  
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public int getNSplitter() Hy'&x?F6  
{
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return nSplitter; -`&;3 7  
} M`'2 a  
+>j_[O5Y  
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public void setNSplitter(int nCount) V-0Y~T  
{ ;{RQ+ZX'[  
nSplitter = nCount; K~R{q+  
} 6yqp<D0SP)  
} $-73}[UA 4  
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/* ^gImb`<6-  
**Utility.java IT|CfQ [D  
*/ L\I/2aiE  
package NetFox; mMH0 o  
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public class Utility { m{|n.b  
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public Utility() 1|--Xnv  
{ wvD|c%   
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} L 'y+^L|X  
= 4L.  
//线程睡眠 q=U=Y n  
public static void sleep(int nSecond) 2cL<`  
{ A7se#"w  
try{ %|Vq"MW,I  
Thread.sleep(nSecond); XQ>m8K?\d  
} +}]xuYzo
 
catch(Exception e) -VL3em|0  
{ ja2LXM  
e.printStackTrace (); }tN"C 3)@  
} y$rp1||lH  
} c{[WOrA~#  
uP.3(n[&  
//日志 t V</x0#  
public static void log(String sMsg) NeH^g0Q2,g  
{ v2NzPzzyb  
System.err.println(sMsg); L,$9)`j  
} ;IyQqP#,<  
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public static void log(int sMsg) 'a}pWkLB  
{ :v#3;('7  
System.err.println(sMsg); YRFM1?*  
} 74_ji!  
} B4%W,F:@  
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/* bTJ7RqL  
**TestMethod.java #H|]F86(  
*/ K=V)"v5o3  
package NetFox; /}Max@.`  
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public class TestMethod { 3LG)s:p$/  
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public TestMethod() QM=X<?m/,=  
{ ///xx/weblogic60b2_win.exe IsI\T8yfc  
try{ tq{ aa  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |X>:"?4t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 278 6tZF,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @AJt/wPk  
fileFetch.start(); >
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} K:mb$YJ&  
catch(Exception e){e.printStackTrace ();} g94NU X  
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} f -bVcWI  
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public static void main(String[] args) Xr-eDUEi  
{ KdUmet
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new TestMethod(); Y>r9"X|&H  
} k z<We/  
} vO 3fAB  
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