http断点续传简单实现（java)

/* ls@]%pz.1d  
**SiteFileFetch.java W91yj:  
*/ F]3Y,{/V  
package NetFox; _HUbE /  
import java.io.*; d<a|dwAeh  
import java.net.*; ,Z"<-%3  
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public class SiteFileFetch extends Thread { &-ropY  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~gfR1SE  
long[] nStartPos; //开始位置 x z_sejKB  
long[] nEndPos; //结束位置 eQbHf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B?VTIq>  
long nFileLength; //文件长度 5BhR4+1J  
boolean bFirst = true; //是否第一次取文件 FO2e7p^Q  
boolean bStop = false; //停止标志 >pU9}2fpT  
File tmpFile; //文件下载的临时信息 5}#wp4U  
DataOutputStream output; //输出到文件的输出流 5WQl?yMP  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） bKo %Ak,  
public SiteFileFetch(SiteInfoBean bean) throws IOException [*',pG  
{ EA& 3rI>U)  
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _VrY7Mz:r  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); PXb$]HV  
if(tmpFile.exists ()) iEvQ4S6tD  
{ U[C4!k:0  
bFirst = false; Mkz_.;3  
read_nPos(); V_+&Y$msi~  
} II\&)_S.4  
else =c[tHf  
{ Y9+_MxC"  
nStartPos = new long[bean.getNSplitter()]; S0,\{j  
nEndPos = new long[bean.getNSplitter()]; HxG8'G  
} R?xb1yc7_  

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} rJ!cma  
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public void run() tEhg',2t(  
{ ,EB}IG]  
//获得文件长度 z5>I9R^q;  
//分割文件 H71sxek3  
//实例FileSplitterFetch Wc3z7xK1@  
//启动FileSplitterFetch线程 HK@ij,px  
//等待子线程返回 .Bm%  
try{ [xMa^A>p  
if(bFirst) g*Y,.  
{ y?$DDD  
nFileLength = getFileSize(); '0+*  
if(nFileLength == -1) 0t <nH%N}^  
{ $83B10OQ&L  
System.err.println("File Length is not known!"); '/W$9jm  
} 8|a./%gixs  
else if(nFileLength == -2) )[Y B&  
{ mayJwBfU  
System.err.println("File is not access!"); lE:g A,  
} %MHb  
else 2{OR#v~  
{ Kgbm/L0XR*  
for(int i=0;i<nStartPos.length;i++) OviS(}v4@  
{ )kD
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); CKsV
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} -pC8
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for(int i=0;i<nEndPos.length-1;i++) h@:K=ggK  
{ Zj`WRH4  
nEndPos = nStartPos[i+1]; :KLXrr  
} uw)7N(os\`  
nEndPos[nEndPos.length-1] = nFileLength; ym%UuC3^w  
} Ni,nQ;9  
} uDF;_bli)H  
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//启动子线程 fr@F7s5}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9njwAKF?  
for(int i=0;i<nStartPos.length;i++) !gsvF\XDM  
{ H];B?G';C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G-aR%]7$g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), M+/xw8}a  
nStartPos,nEndPos,i); 'Uok<;
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mB?x_6#d9  
fileSplitterFetch.start(); .fA*WQ!lb  
} %oZ:Awx  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J$dwy$n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); D Ez,u^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 25^?|9o7  
nEndPos = " + nFileLength); bF'rK'',  
// fileSplitterFetch[nPos.length-1].start(); p9(y b  
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//等待子线程结束 YGp+[|'  
//int count = 0; tK#R`AQ  
//是否结束while循环 K5""%O+  
boolean breakWhile = false; :{lwz
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while(!bStop) o2 14V\  
{ wX$:NOO  
write_nPos(); /ZLY@&M  
Utility.sleep(500); xO~ElzGm  
breakWhile = true; jlEz]@ i  
()
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for(int i=0;i<nStartPos.length;i++) _73q,3`24  
{ ,"(L2+Yp  
if(!fileSplitterFetch.bDownOver) ]Bw0Qq F#  
{ sDY~jP[Oa  
breakWhile = false; IK~&`n](>  
break; [6/QUD8  
}

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} c8RJOc4X  
if(breakWhile) Q?{%c[s  
break; XYE|=Tr]  
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//count++; gv#\}/->4  
//if(count>4) Y+gY"  
// siteStop(); _T=g?0 q  
} VFHd2Ea(  
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System.err.println("文件下载结束！"); 8`Ya7c>  
} eim+oms  
catch(Exception e){e.printStackTrace ();} my=f}%k=  
} RaZ>.5 D  
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//获得文件长度 {pzj@b 1S  
public long getFileSize() 0c_xPBbB+  
{ I`>U#x*  
int nFileLength = -1; v9$!v^U"D  
try{ rr<E#w  
URL url = new URL(siteInfoBean.getSSiteURL()); &4#Zi.]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sE1cvAw9l  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4ls:BO;k]  
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int responseCode=httpConnection.getResponseCode(); 8~sP{V%  
if(responseCode>=400) )8Va%{j  
{ 9 _d2u#  
processErrorCode(responseCode); }x8!{Y#cF  
return -2; //-2 represent access is error 1+o]+Jz|  
} 3>,}N9P-v  
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String sHeader;
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for(int i=1;;i++) s
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{ 95DEuReKi  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Zed
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//Utility.log(in.readLine()); nK&]8"  
sHeader=httpConnection.getHeaderFieldKey(i); ~j0rORy]  
if(sHeader!=null) 'J|2c;M\x  
{ B.z$0=b  
if(sHeader.equals("Content-Length")) 8v:{BHX  
{ ?RRO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8~=*\ @^  
break; y(A' *G9  
} O&`.R|v  
} @@EI=\  
else gcLz}84  
break; 4s\s
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} yDWIflP0;  
} ]B8 A  
catch(IOException e){e.printStackTrace ();} 0.aXg"  
catch(Exception e){e.printStackTrace ();} ]rcF/uQJ<n  
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Utility.log(nFileLength); MB plhVK8  
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return nFileLength;
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} b@:OlZ~%  
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//保存下载信息（文件指针位置） 5&Oc`5QD  
private void write_nPos() 4aayMS!#  
{ Hl*v
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try{ Cu"Cpt[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .UyE|t4  
output.writeInt(nStartPos.length); HL)!p8UHJ  
for(int i=0;i<nStartPos.length;i++) J3$>~?^1  
{ tDByOml8Ix  
// output.writeLong(nPos); 0
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output.writeLong(fileSplitterFetch.nStartPos); Obdn#Wm=  
output.writeLong(fileSplitterFetch.nEndPos); 3? {AGJ1  
} k.T=&0J_1  
output.close(); LZ*8YNp1'  
} -@TY8#O#-  
catch(IOException e){e.printStackTrace ();} 9tiZIm93]  
catch(Exception e){e.printStackTrace ();} g40Hj Y  
} OATdmHW  
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//读取保存的下载信息（文件指针位置） +z >)'#  
private void read_nPos() ?H{[u rLn  
{ N(/)e  
try{ [m~J6WB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .6?"<zdPU  
int nCount = input.readInt(); igO>)XbsM  
nStartPos = new long[nCount]; MDMd$]CW  
nEndPos = new long[nCount]; Lx"GBEkt7  
for(int i=0;i<nStartPos.length;i++) q*!R4yE;C  
{ 'H1~Zhv  
nStartPos = input.readLong(); `y8pwWo-o  
nEndPos = input.readLong(); _\!]MV  
} \j8vf0c5b  
input.close(); ]TV_p[L0B  
} 'C+cQLig@  
catch(IOException e){e.printStackTrace ();} sEhvx+(  
catch(Exception e){e.printStackTrace ();} Mk!Fy]3  
} hU)t5/h;K  
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private void processErrorCode(int nErrorCode) Y
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{ CEy\1D  
System.err.println("Error Code : " + nErrorCode); f@*69a8  
} sqkWQ`Ur  
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//停止文件下载 Spm 0`  
public void siteStop() 6F\ 6,E  
{ %"RJi?  
bStop = true; ]lWqV  
for(int i=0;i<nStartPos.length;i++) yR[6s#F/h  
fileSplitterFetch.splitterStop(); ]4:QqdV  
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} l1KMEGmG  
} hC
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//负责部分文件的抓取 T
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**FileSplitterFetch.java &AiAd6  
*/ ]uXJjS f  
package NetFox; 0B6!$) *-i  
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import java.io.*; GT{4L]C  
import java.net.*; 72HA.!ry  
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public class FileSplitterFetch extends Thread { w[~G^x&  
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String sURL; //File URL ;0DoZ  
long nStartPos; //File Snippet Start Position 9>RkFV  
long nEndPos; //File Snippet End Position $b8[/],  
int nThreadID; //Thread's ID An2>]\L  
boolean bDownOver = false; //Downing is over Kda'N$|`  
boolean bStop = false; //Stop identical mc{z  
FileAccessI fileAccessI = null; //File Access interface !Ko2yn}6l  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )
f?I{  
{ !gh8
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this.sURL = sURL; i_qY=*a?y  
this.nStartPos = nStart; \w9}O2lL  
this.nEndPos = nEnd; WfPb7T  
nThreadID = id; =m.Nm-g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 zJQh~)  
} ;zCUx*{  
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public void run() eORXyh\K  
{ k1&9 bgI  
while(nStartPos < nEndPos && !bStop) `46~j  
{ s$Vl">9#  
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try{ G e;67  
URL url = new URL(sURL); }'[>~&/"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7QO/; zL  
httpConnection.setRequestProperty("User-Agent","NetFox"); G
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String sProperty = "bytes="+nStartPos+"-"; _^ hg7&dF  
httpConnection.setRequestProperty("RANGE",sProperty); *'@Oo  
Utility.log(sProperty); *85N_+Wv!  
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InputStream input = httpConnection.getInputStream(); zt.kNb  
//logResponseHead(httpConnection); vQWmHv\P  
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byte[] b = new byte[1024]; 2z>-H595az  
int nRead; ;"dX]":  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }*fBHzNN  
{ '9\cIni0  
nStartPos += fileAccessI.write(b,0,nRead); sXVl4!=l6  
//if(nThreadID == 1) \Vc[/Qp7Bb  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *g5bdQ:Av~  
} "i&)+dr-  
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Utility.log("Thread " + nThreadID + " is over!"); D e&,^"%  
bDownOver = true; WD5J2EePT  
//nPos = fileAccessI.write (b,0,nRead); zx@!8Z  
} IQ&PPC  
catch(Exception e){e.printStackTrace ();} !y_FbJ8KC  
} bBIh}aDN  
} G'|ql5Zw  
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//打印回应的头信息 r1!1u7dr t  
public void logResponseHead(HttpURLConnection con) ]V"P &
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{ l7`{O/hN  
for(int i=1;;i++) &'6/H/J  
{ HZ3;2k  
String header=con.getHeaderFieldKey(i); S:1[CNL;  
if(header!=null) CPB{eQeDuv  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Es>' N3A z  
Utility.log(header+" : "+con.getHeaderField(header)); 6Bq_<3P_  
else 5CK+\MK  
break; A f'&, 1=q  
} ~5 6&!4  
} )
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public void splitterStop() s;A7:_z#7  
{ a1pp=3Pd?~  
bStop = true; @i ~A7L0/  
} @=kgK[t 9  
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} =lAjQt
 
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/* o~$O$  
**FileAccess.java  Bx45yaT  
*//文件访问(定位，写) A]c
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package NetFox; bM?gAY]mB8  
import java.io.*; 7O1MC 8{  
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public class FileAccessI implements Serializable{ XFWpHe_ L  
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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 tW/k  
RandomAccessFile oSavedFile; EE9w^.3a  
long nPos; *}2L4]  
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public FileAccessI() throws IOException q,Gymh;  
{ puPI^6y%  
this("",0); 97liSd  
} dWz?`B{'  
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public FileAccessI(String sName,long nPos) throws IOException *)K\&h<{  
{ 1L,L/sOwB&  
oSavedFile = new RandomAccessFile(sName,"rw"); R-%6v2;ry  
this.nPos = nPos; $0$sM/%  
oSavedFile.seek(nPos); NP;W=A F  
} 0AHQ(+Ap  
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public synchronized int write(byte[] b,int nStart,int nLen) $udhTI#,  
{ 44KoOY_  
int n = -1; N3"JouP  
try{ t7byOMC  
oSavedFile.write(b,nStart,nLen); "$(+M t^  
n = nLen; a``|sn9  
} ]g-%7g|
 
catch(IOException e) JuO47}i]5  
{ ~,/@]6S&Y  
e.printStackTrace (); ?tYZ/  
} .D@J\<,+l  
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return n; Ki><~!L  
} C8K2F5c5  
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}  GK/Po51  
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/* JP8}+  
**SiteInfoBean.java Et3I(X3  
*/ 2.3_FXSt  
package NetFox; [6a-d>e{  
l!*_[r  
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public class SiteInfoBean { t"$~o:U&)  
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private String sSiteURL; //Site's URL <>6j>w_|  
private String sFilePath; //Saved File's Path u1/>)_U  
private String sFileName; //Saved File's Name b,Wm
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private int nSplitter; //Count of Splited Downloading File =zFROB\  
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public SiteInfoBean() v@$N,g  
{//nSplitter的缺省值为5 9JFN8Gf*)  
//default value of nSplitter is 5 m?kiGC&m  
this("","","",5); AM-bs^  
} -PV1x1|
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) dk&e EDvfd  
{ z>N[veX%  
sSiteURL= sURL;
:7K a4  
sFilePath = sPath; Et3]n$  
sFileName = sName; 
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this.nSplitter = nSpiltter; 0j@mzd2  
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T >8P1p@A,  
} iTHwH{!  
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public String getSSiteURL() [1rQ'FBB^1  
{ =muQ7l:(  
return sSiteURL; "'CvB0>  
} z>PVv)X  
=\6)B{#T  
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public void setSSiteURL(String value) e)uC  
{ Dck/Ea  
sSiteURL = value; aEN`
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} %O`@}Tg  
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public String getSFilePath() IWE([<i}i[  
{ mI8EeMa{  
return sFilePath; `Na()r$T  
} "VZ1LVI  
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public void setSFilePath(String value) ;g0s1nz  
{ rMwa6ZO'm;  
sFilePath = value; jf3Zy:*K  
} t2,II\Kl  
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public String getSFileName() ]ogifnwv  
{ $5pCfW8>  
return sFileName; ZO/e!yju  
} r(r(&NU  
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public void setSFileName(String value) eB~\~@  
{  u 8o!  
sFileName = value; JwMRquQv  
} @V:K]M 5  
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public int getNSplitter() VgbNZ{qk@  
{ ^t'mW;C$4  
return nSplitter; eJoM4v  
} p-$C*0{  
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public void setNSplitter(int nCount) o"JHB  
{ +,spC`M6h  
nSplitter = nCount; /<-PW9X?  
} #czInXTTx  
} "-f]d~P>  
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/* Ubu&$4a  
**Utility.java s:_hsmc"  
*/ W|2^yO,dX  
package NetFox; ]KuM's  
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public class Utility { jnqp" Ult>  
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public Utility() %R$)bGT  
{ 5
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} }#1.$a  
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//线程睡眠 8 o}5QOW  
public static void sleep(int nSecond) "22./vWV|i  
{ mRx `G(u:v  
try{ v.W!  
Thread.sleep(nSecond); ,P<I<QYu  
} ?`TJ0("z"  
catch(Exception e) Mh`^-*c?  
{ #N`'hPD}  
e.printStackTrace (); I0Do%  
} Q3>qT84  
} '\{ OQH  
U>t:*SNC*  
//日志 oRd{?I&NY  
public static void log(String sMsg) J.rS@Z`~7  
{ !&OdbRHM  
System.err.println(sMsg); *?Eu{J){7%  
} >> cW0I/`  
f
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public static void log(int sMsg) V.3#O^S  
{ _3 [E$Lg  
System.err.println(sMsg); I&|8 qx#  
} UP-2{zb |?  
} gS(JgN  
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o,k#ft<  
/* 5M\0t\uEn  
**TestMethod.java IO#)r[JZ  
*/ 36'J9h\  
package NetFox; (a!E3y5,  
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public class TestMethod { w32F?78]  
0D:uM$ i]  
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public TestMethod() F4(;O7j9  
{ ///xx/weblogic60b2_win.exe gu3)HCZ  
try{ yq3"VFh3d  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &\?{%xj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #O^zA`D   
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ql7opl,  
fileFetch.start(); M-Nn \h$,  
} k'$7RjCu  
catch(Exception e){e.printStackTrace ();} "~C\Z} ;  
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} zh !/24p9  
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public static void main(String[] args) P)TeF1~T  
{ 'H1"z!]  
new TestMethod(); 7.5\LTM>9e  
} [u3^R]  
} +&AU&2As  
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