http断点续传简单实现（java)

/* ~-<MoCm!  
**SiteFileFetch.java h@E7wp1'~  
*/ ]1FLG*sB  
package NetFox; lJ]]FuA-Q  
import java.io.*; zYrJHn#vB  
import java.net.*; nY7gST  
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public class SiteFileFetch extends Thread { X%)~i[_DV  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 35Fxzj $  
long[] nStartPos; //开始位置 O6
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long[] nEndPos; //结束位置 HKr}"`I.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 iciKjXJ:  
long nFileLength; //文件长度 #i.,+Q  
boolean bFirst = true; //是否第一次取文件 ZNne
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boolean bStop = false; //停止标志 #}Yrxf  
File tmpFile; //文件下载的临时信息 DuN
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DataOutputStream output; //输出到文件的输出流 c<,LE@V  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8\"Gs z  
public SiteFileFetch(SiteInfoBean bean) throws IOException }zks@7kf  
{ t7l{^d_L  
siteInfoBean = bean; 5F+G8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); T60pw  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n\)1Bz  
if(tmpFile.exists ()) 7nNNc[d*=  
{ CIz0Gjtx6m  
bFirst = false; pU9.#O  
read_nPos(); 5RvE ),  
} 1 _Oc1RM   
else JOpH Z?  
{ T>]T=  
nStartPos = new long[bean.getNSplitter()]; &e6UEG  
nEndPos = new long[bean.getNSplitter()]; r<vy6  
} 3
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} 5VP0Xa ~  
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public void run() /q+;!E
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{ F@k}p-e~  
//获得文件长度 9Q^cE\j  
//分割文件 qC{JsX`~  
//实例FileSplitterFetch |ZE^'e*k  
//启动FileSplitterFetch线程 t"Ci1"U  
//等待子线程返回 En1LGi4#  
try{ u -P !2vT  
if(bFirst) RYA@{.O  
{ !b7"K|  
nFileLength = getFileSize(); }dop]{RG  
if(nFileLength == -1) EwX&Cj".  
{ I-Z|FKh_C  
System.err.println("File Length is not known!"); vue^bn  
} * eC[74Kng  
else if(nFileLength == -2) );':aXj  
{ +^lB"OcOX@  
System.err.println("File is not access!"); ?WHf%Ie2(  
} #H w(w  
else iX6>u4~(  
{ Vn4wk>b}$2  
for(int i=0;i<nStartPos.length;i++) :u./"[G  
{ GE(~d'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3PGAUQR#"q  
} _<LL@IX  
for(int i=0;i<nEndPos.length-1;i++) @U18Dj[  
{ MNWI%*0LO  
nEndPos = nStartPos[i+1]; Fu_I0z  
} VK]U*V1  
nEndPos[nEndPos.length-1] = nFileLength; UL-_z++G  
} sa4w.9O1GS  
} J6n>{iE  
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//启动子线程 Mn(iAsg  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Z.Yq)\it  
for(int i=0;i<nStartPos.length;i++) z,G_&5|f%  
{ hp)^s7H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Cl`i|cF\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _yv#v_Z  
nStartPos,nEndPos,i); c%C6d97q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >i,_qe?V:w  
fileSplitterFetch.start(); 1*9.K'
 
} &K\80wGK  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :${tts2g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #G77q$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", UMR?q0J  
nEndPos = " + nFileLength); vUJ;D  
// fileSplitterFetch[nPos.length-1].start(); 8Rwk o6x  
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//等待子线程结束
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//int count = 0; X n$ZA-  
//是否结束while循环 R,G*]/r`  
boolean breakWhile = false; :R,M Y"(  
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while(!bStop) b/'c h  
{ Mg.%&vH\  
write_nPos(); X+aQ 7^"s  
Utility.sleep(500); = 'NV3by  
breakWhile = true; hr}f5Z)^v  
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for(int i=0;i<nStartPos.length;i++) & "&s,  
{ G n]qh(N>  
if(!fileSplitterFetch.bDownOver) &bW,N  
{ <ToBVGX  
breakWhile = false; Lj3o-@\*j  
break; h6 {vbYj  
} Nv7-6C6<  
} }+9?)f{?@  
if(breakWhile) KOS0Du  
break; H\Ra*EO~j  
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N s+g9+<A  
//count++; g0t
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//if(count>4) ?`piie9V  
// siteStop(); YpDJ(61+  
} z6iKIw $  
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System.err.println("文件下载结束！"); $V(]z`b&  
} I "AjYv4R  
catch(Exception e){e.printStackTrace ();} ^m w]u"5\  
} x,,y}_YX  
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//获得文件长度 ma~#E$i&  
public long getFileSize() iYStl  
{ F3}MM dX  
int nFileLength = -1; {h?pvH_>  
try{ &J6
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URL url = new URL(siteInfoBean.getSSiteURL()); N&NBn(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }`B .(3n  
httpConnection.setRequestProperty("User-Agent","NetFox"); _]`7et\=  
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int responseCode=httpConnection.getResponseCode(); ]nhh|q9r{  
if(responseCode>=400) #{8IFA  
{ @f-X/q]P  
processErrorCode(responseCode); ST*h{:u&A  
return -2; //-2 represent access is error N-M.O:p  
} hpAdoy[  
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String sHeader; xol%\$|  
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for(int i=1;;i++) 1Z# $X`  
{ vA/SrX.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >!=@TK(~  
//Utility.log(in.readLine()); d05xn7%!{  
sHeader=httpConnection.getHeaderFieldKey(i); .11l(M  
if(sHeader!=null) 1>J.kQR^  
{ M~taZt4  
if(sHeader.equals("Content-Length")) N(&{~*YE  
{ 4X
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !=dz^f.{  
break; u
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} l_^OdQ9D  
} ,X?/FAcb
 
else *-T.xo  
break; (;l
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} RQ,#TbAe  
} l00i2w  
catch(IOException e){e.printStackTrace ();} cc[(w #K  
catch(Exception e){e.printStackTrace ();} #fuUAbU0X  
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Utility.log(nFileLength); 3V
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return nFileLength; P@7>R7
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} QQl.5'PP  
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//保存下载信息（文件指针位置） v)5;~.+%  
private void write_nPos() 6 4_}"fU  
{ Fw<"]*iu  
try{ #1<m\z7l  
output = new DataOutputStream(new FileOutputStream(tmpFile)); C]L)nCOBX  
output.writeInt(nStartPos.length); 51k}LH  
for(int i=0;i<nStartPos.length;i++) W:r[o%B  
{ <o(;~  
// output.writeLong(nPos); C>Ik ;  
output.writeLong(fileSplitterFetch.nStartPos); (!}N&!t  
output.writeLong(fileSplitterFetch.nEndPos); 6Og@tho  
} 8+'}`  
output.close(); T)! }Wvv  
} <XeDJ8 '  
catch(IOException e){e.printStackTrace ();} k1B ](@xt  
catch(Exception e){e.printStackTrace ();} ~fXNj-'RW  
} uKJ:)oyaCP  
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//读取保存的下载信息（文件指针位置） F
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private void read_nPos() ?@"@9na  
{ i2qN 0?n  
try{ V;SfW2`)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +Br<;sW  
int nCount = input.readInt(); C @Ts\);^  
nStartPos = new long[nCount]; %KyZ15_(-L  
nEndPos = new long[nCount]; M^kaik  
for(int i=0;i<nStartPos.length;i++) db )2>  
{ ZX_QnSNZ?  
nStartPos = input.readLong(); :|j[{;asY  
nEndPos = input.readLong(); 3!P^?[p3  
} kepuh%KY[  
input.close(); +Y?Tri  
}  4!!|P  
catch(IOException e){e.printStackTrace ();} uz3cho'  
catch(Exception e){e.printStackTrace ();} 0AnL]`"t.3  
} Z!v,;MW  
#]Vw$X_S  
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private void processErrorCode(int nErrorCode) ~A0AB `7  
{ Q 8]X  
System.err.println("Error Code : " + nErrorCode); Zr}>>aIJ]k  
} tY_=[6?Zu  
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//停止文件下载 L91(|gQP  
public void siteStop() W8<QgpV*  
{ }cz
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bStop = true; 0hS&4nW  
for(int i=0;i<nStartPos.length;i++) ZRhk2DA#FF  
fileSplitterFetch.splitterStop(); 4W>DW`{  
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} Kj0)/Fjl+  
} }%KQrlbHJl  
//负责部分文件的抓取 &tOo[U?  
**FileSplitterFetch.java GVT 6cR  
*/ X}[1Y3~y  
package NetFox; " lD -*e4  
n l5+#e*\  
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import java.io.*; %Vo'\|  
import java.net.*; eGMw:H  
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public class FileSplitterFetch extends Thread { #mH28UT  
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String sURL; //File URL y1`%3\  
long nStartPos; //File Snippet Start Position 6~ET@"0uK  
long nEndPos; //File Snippet End Position 0Cc3NNdz  
int nThreadID; //Thread's ID [?z;'O}y  
boolean bDownOver = false; //Downing is over Va[&~lA)  
boolean bStop = false; //Stop identical #W:.Fsq  
FileAccessI fileAccessI = null; //File Access interface qRT5|\l  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 65B&>`H~  
{ hQ3@CfW  
this.sURL = sURL; 4gZR!J  
this.nStartPos = nStart; b?k,_;\  
this.nEndPos = nEnd; ruhC:rg:/  
nThreadID = id; :Nz TEK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 aeMj4|{\  
} FkMM>X  
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public void run() p7},ymQ|YQ  
{ 9'X"a  
while(nStartPos < nEndPos && !bStop) "dG*HKrr  
{ ml~)7J  
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try{ `34+~;;Jh  
URL url = new URL(sURL); UeUOGf ,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j;Z hI y  
httpConnection.setRequestProperty("User-Agent","NetFox"); "97sH_ ,  
String sProperty = "bytes="+nStartPos+"-"; MO]zf3f!  
httpConnection.setRequestProperty("RANGE",sProperty); 9aID&b+  
Utility.log(sProperty); !ggHLZRlz  
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InputStream input = httpConnection.getInputStream(); 0l(G7Ju  
//logResponseHead(httpConnection); *{fZA;<R  
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byte[] b = new byte[1024]; V2Z
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int nRead; 'mU\X!- 4<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
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{ ZU:c[`  
nStartPos += fileAccessI.write(b,0,nRead); q|.0Ja  
//if(nThreadID == 1) Dhft[mvo  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B)DtJf  
} 17rg!'+   
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Utility.log("Thread " + nThreadID + " is over!"); .v) A|{:2  
bDownOver = true; $a')i<m^g  
//nPos = fileAccessI.write (b,0,nRead); mqQ//$Y   
} B3u:D"
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catch(Exception e){e.printStackTrace ();} BBoVn^Z*R  
} Xt
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} :JxuaM8  
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( Qk*B  
//打印回应的头信息 -A8CW9|mk  
public void logResponseHead(HttpURLConnection con) }8'bXG+  
{ jW|M)[KJN  
for(int i=1;;i++) BfvvJh_  
{ orF8%  
String header=con.getHeaderFieldKey(i); xirZ.wjW  
if(header!=null) v3/G.B@=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); H+5N+AKb@  
Utility.log(header+" : "+con.getHeaderField(header)); l;JB;0<s"  
else "CQ:<$|$  
break; [{-;cpM\  
} K30{Fcb< h  
} r/ LgmVRn  
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public void splitterStop() \H?r[]*c%  
{ "Kn%|\YL@4  
bStop = true; [1`&\C_E  
} 4q^'MZm1  
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} I_h&35^t  
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/* 7NfA)$  
**FileAccess.java *p%=u>?&  
*//文件访问(定位，写) [lAZ)6E~=  
package NetFox; 4}HY= 0Um  
import java.io.*; >uDE<MUC  
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public class FileAccessI implements Serializable{ -6>T0-  
7%^/Jm  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^5*9BwH`  
RandomAccessFile oSavedFile; h.h\)>DM@  
long nPos; ^b`aO$  
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public FileAccessI() throws IOException Ut^ {4_EC  
{ V> @+&q  
this("",0);  HO =\  
} 0=KyupwXC  
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public FileAccessI(String sName,long nPos) throws IOException r5\|%5=J  
{ 5"9!kZ(<  
oSavedFile = new RandomAccessFile(sName,"rw"); [E|%  
this.nPos = nPos; iwnFCZVS  
oSavedFile.seek(nPos); rXu^]CK *G  
} &,~Oi(SX5  
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public synchronized int write(byte[] b,int nStart,int nLen) 4brKAqg.  
{ dJD8c2G  
int n = -1; ?Q%X,!~\:  
try{ 0T7""^'&  
oSavedFile.write(b,nStart,nLen); gCY%@?YyN  
n = nLen; Z |CL:)h  
} -mK;f$X  
catch(IOException e) EG[Rda  
{ |.Y}2>{  
e.printStackTrace (); "_ i:  
} .a`(?pPr,  
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return n; f& >[$zh  
} 8!(09gW'>  
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} ?B~S4:9  
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/* =;?afUj  
**SiteInfoBean.java fC$(l@O?  
*/ ijR,%
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package NetFox; 7awh__@  
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public class SiteInfoBean { ;HbAk`\1A  
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private String sSiteURL; //Site's URL TO~Z6NA0  
private String sFilePath; //Saved File's Path >")<pUQ  
private String sFileName; //Saved File's Name Tweku}D7  
private int nSplitter; //Count of Splited Downloading File w5uOkz #  
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public SiteInfoBean() eQqx0+-0c  
{//nSplitter的缺省值为5
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//default value of nSplitter is 5 $(8CU$gi=  
this("","","",5); I=G-(L/&  
} (!B1}5"  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) yTb#V"e
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{ J
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sSiteURL= sURL; c Y(2}Ay  
sFilePath = sPath; 5b5Hc Inu
 
sFileName = sName; R *uwp'@  
this.nSplitter = nSpiltter; 7)#8p@Q  
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=  
} $\A=J  
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public String getSSiteURL() n3Q Rn^  
{ }5qpiS"V9  
return sSiteURL; $zUHka  
} Yg kd1uI.  
l" P3lKS  
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public void setSSiteURL(String value) O4.`N?Xq  
{ vle`#c.  
sSiteURL = value; r#X6jU  
} MGU%"7i'}  
.L#U^H|  
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public String getSFilePath() 0c6Ea>S[  
{ 8.m9 =+)8  
return sFilePath; ]w;!x7bU(  
} e"O c  
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public void setSFilePath(String value) ]oIP;J:&  
{ 1HS43!  
sFilePath = value; @&xWd{8'  
} [ qx[ 0  
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public String getSFileName() :'0.  
{ DP5}q"l  
return sFileName; la}Xo0nq0+  
} Yw_^]:~  
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public void setSFileName(String value)
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{ !}pvrBS  
sFileName = value; ews{0  
} A$o7<Hx  
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public int getNSplitter() KqhE=2,  
{ i_<GSUTTr/  
return nSplitter; /=IBK`  
} &~{0@/
 
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1 ` ={**  
public void setNSplitter(int nCount) VteMsL/H  
{ YM.Q?p4g  
nSplitter = nCount; DICS6VG}  
} 5|_El/G  
} 3K{G=WE$  
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/* fZka$ 4  
**Utility.java vMv? fE"  
*/ f)#rBAkt  
package NetFox; w)7s]Ld  
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public class Utility { "l[ c/q[  
+b_o2''  
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public Utility() wT@{=s,  
{ }>$3B5}  
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} !}I+)@~
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={[9kR i  
//线程睡眠 bSgdVP-  
public static void sleep(int nSecond) $*q^7ME  
{ S\<nCkE^  
try{ !>,XK!)  
Thread.sleep(nSecond); N4rDe]JnPR  
} 7;r Jr&.)  
catch(Exception e) X]+z:!  
{ "rU 2g  
e.printStackTrace (); #,B+&SK{  
} k.<OO  
} 8d1r#sILI  
, G9{:  
//日志 >eM>Y@8=  
public static void log(String sMsg) N.F
//n  
{ B x-"<^<  
System.err.println(sMsg); W!B\VB  
} w 21g&  
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public static void log(int sMsg) vugGMP;D(  
{ 4RL0@)0F  
System.err.println(sMsg); |] cFsB#G  
} D*}_

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} iTcq=  
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/* |f{(MMlj  
**TestMethod.java ,%d?gi"&  
*/ 2#)z%K6T  
package NetFox; lcfX(~/m^  
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public class TestMethod { Ng|c13A=  
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public TestMethod() )SzgMbF6  
{ ///xx/weblogic60b2_win.exe a?1Ml>R6P  
try{ 'bn$"A"{o  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); m<I>NYfE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <_3OiU=w  
SiteFileFetch fileFetch = new SiteFileFetch(bean); lQKq{WLFx.  
fileFetch.start(); WY$c^av<  
} vocWV/  
catch(Exception e){e.printStackTrace ();} i{biQ|,.sL  
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} )QAS7w#k  
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public static void main(String[] args) -jk-ve  
{ =`E{QCW  
new TestMethod(); Ft<B[bQ  
} :rSCoi>K  
} ~%!"!Z4  
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