http断点续传简单实现（java)

/* pF8:?p['z  
**SiteFileFetch.java ) LTV+?  
*/ Qz%q#4Zb  
package NetFox; !r/~D |  
import java.io.*; Fm6]mz%~u#  
import java.net.*; b9 li  
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public class SiteFileFetch extends Thread { X*d!A >s  
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SiteInfoBean siteInfoBean = null; //文件信息Bean DB_oRr[oj  
long[] nStartPos; //开始位置 KbK!4  
long[] nEndPos; //结束位置 tx`^'%GMA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 0]]OE+
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long nFileLength; //文件长度 I69Z'}+qz  
boolean bFirst = true; //是否第一次取文件 p} 
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boolean bStop = false; //停止标志 U
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File tmpFile; //文件下载的临时信息 ;'Z"CbS+  
DataOutputStream output; //输出到文件的输出流 Qm"~XP  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） QyZ'%T5J  
public SiteFileFetch(SiteInfoBean bean) throws IOException &G\C[L  
{ $kMe8F_  
siteInfoBean = bean; +ek6}f
#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }NdLd!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  w+5OI9  
if(tmpFile.exists ()) U-f8D  
{ Y(EF )::  
bFirst = false; VAyAXN~  
read_nPos(); Lk^bzW>f  
} c5O8,sT  
else X9^q-3&60  
{ hg'eSU$J  
nStartPos = new long[bean.getNSplitter()]; Ep')@7^n  
nEndPos = new long[bean.getNSplitter()]; n%~r^C_  
} qxZf!NX5  
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}
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public void run() [kgCB7.V  
{ H&k&mRi  
//获得文件长度 G'nSnw  
//分割文件  0XyPG  
//实例FileSplitterFetch [E2".F3  
//启动FileSplitterFetch线程 Zny9TP  
//等待子线程返回 {%,4P_m  
try{ PtL8Kd0`C  
if(bFirst) .uN(44^+x  
{ uLI;_,/:  
nFileLength = getFileSize(); JZ-64OT  
if(nFileLength == -1) G[OJ<px  
{ qk0cf~gz  
System.err.println("File Length is not known!"); Rx.5;2m  
} h_\W7xt  
else if(nFileLength == -2) Lc-WfzT  
{ &rG]]IO  
System.err.println("File is not access!"); iP$>/[I  
} +9<:z
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else X"HVK+  
{ />>KCmc  
for(int i=0;i<nStartPos.length;i++) RcO.1@2  
{ [?2?7>D8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); eU]I !pI<  
} %)&Tr`  
for(int i=0;i<nEndPos.length-1;i++) x&EMg!  
{ ZHoYnp-~z  
nEndPos = nStartPos[i+1]; ^b=;  
} 2:yXeSeA  
nEndPos[nEndPos.length-1] = nFileLength; %Z*)<[cIE0  
} aouYPxA`  
} Rdj^k^V+a1  
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yaHkWkl =  
//启动子线程 ]{ch
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; N\CHIsVm>  
for(int i=0;i<nStartPos.length;i++) 5fmQ+2AC1  
{ ~1
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~)ysEZl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `\=~ $&vjC  
nStartPos,nEndPos,i); k6\&[BQs  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !rG-[7K  
fileSplitterFetch.start(); : 'pK  
} [V5,1dmkI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /7-FVqDx8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |Fq\%y#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xZQyH  
nEndPos = " + nFileLength); C]na4yE8  
// fileSplitterFetch[nPos.length-1].start(); =">0\#  
b%VZPKA;  
!!~r1)zN  
//等待子线程结束 PevT`\>  
//int count = 0; CXi:?6OG  
//是否结束while循环 P(LiH  
boolean breakWhile = false; ykGA.wo7/P  
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while(!bStop) m*KI'~#$%
 
{ E*+]Iq1u  
write_nPos(); "!D,9AkZS  
Utility.sleep(500); 9*r l7  
breakWhile = true; Jl$ X3wE  
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for(int i=0;i<nStartPos.length;i++) 5<7sVd.  
{ i3$pqNe  
if(!fileSplitterFetch.bDownOver) x3nUKQtk:8  
{ @U =~c9  
breakWhile = false; YH{n   
break; sAF="uB  
} F$O$Y[  
} 7D
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if(breakWhile) q$}gQ9'z'  
break; lKS 2OOYC`  
>.hDt9@4  
]qEg5:yY  
//count++; !H6X%hlk  
//if(count>4) k#8E9/t@  
// siteStop(); hF5(1s}e$  
} QEF$Jx  
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}8`>n4  
System.err.println("文件下载结束！"); =L{-Hu/j  
} LeNSjxB  
catch(Exception e){e.printStackTrace ();} 7~L_>7;  
} SES-a Mi3  
IL"N_ux~w~  
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//获得文件长度 JX#0<U|L  
public long getFileSize() q&LCMnv"P  
{ Xv 7no
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int nFileLength = -1; 
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try{ Iq 0ew  
URL url = new URL(siteInfoBean.getSSiteURL()); ENFM``dV#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $|AasT5w  
httpConnection.setRequestProperty("User-Agent","NetFox"); r5NH*\Q  
@eq.&{&  
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int responseCode=httpConnection.getResponseCode(); 9xFI%UOb#  
if(responseCode>=400) XcL%0%`  
{ 8U!$()^?  
processErrorCode(responseCode); Q2* ~9QkU  
return -2; //-2 represent access is error #WAX&<m  
} Mu6DTp~k  
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String sHeader; B|'}HBkP  
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for(int i=1;;i++) , Yl
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{ > iYdr/^a  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); E5Sn mxd  
//Utility.log(in.readLine());  "+Sq}WR  
sHeader=httpConnection.getHeaderFieldKey(i); (/X]9  
if(sHeader!=null) zU_dk'&,  
{ dEW= V"W  
if(sHeader.equals("Content-Length")) j-ob7(v)*]  
{ ]ZNFrpq  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); WuTkYiF  
break; -"?~By}<C  
} </aQ  
} Z$zX%w  
else g1(5QWb  
break; {CNJlr@z  
} 6?[SlPPE1  
} A;o({9VH`Z  
catch(IOException e){e.printStackTrace ();} KL$>j/qT  
catch(Exception e){e.printStackTrace ();} )g}G{9M^  
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Utility.log(nFileLength); 9}Ge@a<j  
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return nFileLength; NytodVZ'3  
} #&1gVkvp  
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,+I]\ZeO  
//保存下载信息（文件指针位置） M^>l>?#rl  
private void write_nPos() t*H|*L#YR  
{ WWo"De@  
try{ zQ<;3+*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7AWq3i{  
output.writeInt(nStartPos.length); 69apTx  
for(int i=0;i<nStartPos.length;i++) gsl_aW!  
{ R0LWuE%eD  
// output.writeLong(nPos); 6a_U[-a9;  
output.writeLong(fileSplitterFetch.nStartPos); DbX7?Jr  
output.writeLong(fileSplitterFetch.nEndPos); pZ3sp!  
} ~*<`PDO?  
output.close(); LsaX HI/?b  
} zmL VFGnS  
catch(IOException e){e.printStackTrace ();} \sfc!5G  
catch(Exception e){e.printStackTrace ();} qywl G  
} GIn%yB'  
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//读取保存的下载信息（文件指针位置） dUl"w`3  
private void read_nPos() c h((u(G
 
{ ,2+d+Zuh  
try{ >]C/ Q6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ! Vlx  
int nCount = input.readInt(); b{{ H@LTW  
nStartPos = new long[nCount]; !H{>c@i  
nEndPos = new long[nCount]; ;Bj&9DZd  
for(int i=0;i<nStartPos.length;i++) 8{ =ha  
{ `h'=F(v(}  
nStartPos = input.readLong(); E)f9`][  
nEndPos = input.readLong(); (E&M[hH+  
} \i@R5v=zL  
input.close(); WVKAA.  
} !.q9:|oc  
catch(IOException e){e.printStackTrace ();} M_.Jmh<&&  
catch(Exception e){e.printStackTrace ();} ^cSfkBh  
} R5((
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private void processErrorCode(int nErrorCode) U1pE2o-  
{ CSq|R-@<U  
System.err.println("Error Code : " + nErrorCode);
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} V45adDiZ  
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//停止文件下载 %"fO^KA.h]  
public void siteStop() o$Nhx_F  
{ &GJVFr~z  
bStop = true; zwJ&K;"y(  
for(int i=0;i<nStartPos.length;i++) >~Tn%u<  
fileSplitterFetch.splitterStop(); #\n*Qg4p  
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} 4;CI<&S  
} 3W_7xLA  
//负责部分文件的抓取 `XK\', }F  
**FileSplitterFetch.java TNA7(<"fV|  
*/ Pmd[2/][  
package NetFox; Q1x&Zm1v  
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import java.io.*; GN! R<9  
import java.net.*; :DNI\TmhJ  
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public class FileSplitterFetch extends Thread { DwGM+)!  
#G F.M,O/h  
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String sURL; //File URL bo\Ah/.  
long nStartPos; //File Snippet Start Position Qg(;>ops  
long nEndPos; //File Snippet End Position gH'hA'  
int nThreadID; //Thread's ID ([>__c/Nd  
boolean bDownOver = false; //Downing is over
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boolean bStop = false; //Stop identical EC[]L'IL  
FileAccessI fileAccessI = null; //File Access interface 2z;3NUL$n  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C5I7\9F)  
{ l9a81NF{s  
this.sURL = sURL; Sqb>aj  
this.nStartPos = nStart; W$NFk(  
this.nEndPos = nEnd; eUB!sR%  
nThreadID = id; n(eo_.W2|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 xi "3NF%=  
} ;)CN=J!  
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.9B@w+=6  
public void run() <Y?Z&rNb  
{
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while(nStartPos < nEndPos && !bStop) g*YA~J@  
{ ^#Q-?O  
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try{ O]=jI  
URL url = new URL(sURL); qQ3Q4R\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AJ*17w  
httpConnection.setRequestProperty("User-Agent","NetFox"); +39uKOrZ  
String sProperty = "bytes="+nStartPos+"-"; rmkBp_i{|  
httpConnection.setRequestProperty("RANGE",sProperty); 8Z\q)

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Utility.log(sProperty); H6 x  
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InputStream input = httpConnection.getInputStream(); u]Vt>Ywu  
//logResponseHead(httpConnection); b=
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byte[] b = new byte[1024]; 95@u|#n  
int nRead; ZOV,yuD{8{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) SQf[1}$ .  
{ # 2^H{7  
nStartPos += fileAccessI.write(b,0,nRead); @~ke=w6&pe  
//if(nThreadID == 1) o;Z"I&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }?mSMqnB  
} nN<,rN{:  
p )JR5z  
#!O)-dyF  
Utility.log("Thread " + nThreadID + " is over!"); QlMLWi  
bDownOver = true; >@ 8'C"F  
//nPos = fileAccessI.write (b,0,nRead); COHBjufmR  
} V||b%Cb1g  
catch(Exception e){e.printStackTrace ();} +0%r@hTv&>  
} q9ra  
} RDDA^U7y#  
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//打印回应的头信息 :B5*?x  
public void logResponseHead(HttpURLConnection con) p#P<V%  
{ #b428-  
for(int i=1;;i++) ^\B4]'+^j  
{ }W 5ks-L6  
String header=con.getHeaderFieldKey(i); 6}R*7iMs  
if(header!=null) Jb*QlsGd  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); aeN #<M&$<  
Utility.log(header+" : "+con.getHeaderField(header)); |^5"-3Q  
else C=&n1/  
break; hq{{XQ  
} $6UU58>n  
} &UnhYG{A  
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public void splitterStop() Am@Ta "2  
{ ?'f  
bStop = true; 2C:u)}R7D  
} , 2#Q>  
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!?ZR_=Y%  
} >i  
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/* Ek `bPQ5  
**FileAccess.java !\{2s!l~  
*//文件访问(定位，写) 0!YVRit\N  
package NetFox; bl>W
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import java.io.*; TE
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public class FileAccessI implements Serializable{ "Ua-7Q&A  
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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 Peph..8Z  
RandomAccessFile oSavedFile; y>t:flD*  
long nPos; &uE )Vr4R  
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public FileAccessI() throws IOException u{=h%d
/  
{ +Eb-|dM  
this("",0); 3xW:"  
} T'7>4MT(  
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public FileAccessI(String sName,long nPos) throws IOException vjGJRk|XED  
{ -eK0 +beQ  
oSavedFile = new RandomAccessFile(sName,"rw"); w{T$3F`@9  
this.nPos = nPos; "2C}Pr,p8  
oSavedFile.seek(nPos); [g@qZ5I.  
} N e{=KdzT  
.{ILeG  
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public synchronized int write(byte[] b,int nStart,int nLen) J&h59dm-  
{ :kI[Pf!z  
int n = -1; X4:84  
try{ jbe:"Stw  
oSavedFile.write(b,nStart,nLen); PO'K?hVS^w  
n = nLen; lGp:rw`
 
} {~51h}>b#  
catch(IOException e) L''VBY"?  
{ -eV*I>G  
e.printStackTrace ();
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} y~]D402Cx  
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return n; 3
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} X$ul=iBs  
@ ^F{  
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} KQ9w>!N[  
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/* rusM]Z  
**SiteInfoBean.java E%E`\mFD  
*/ "&D0Sd@[?  
package NetFox; LC=M{\  
 K%%Ow  
3`SH-"{j%  
public class SiteInfoBean { %jj-\Gz!  
)ZLj2H<  
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private String sSiteURL; //Site's URL '.pGkXyQ  
private String sFilePath; //Saved File's Path ]5*H/8Ke7  
private String sFileName; //Saved File's Name -ys/I,}<  
private int nSplitter; //Count of Splited Downloading File #gWok'ZcR  
rLD1Cpeb,w  
@~$=96^  
public SiteInfoBean() KMb
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{//nSplitter的缺省值为5 ^|h_[>  
//default value of nSplitter is 5 2.);OFk+  
this("","","",5); 7?k3jDK  
} W=S^t_F  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j3w~2q"r  
{ ~IO'"h'w  
sSiteURL= sURL; U%1M?vT/  
sFilePath = sPath; $ta"Ug.z  
sFileName = sName; Z[z" v  
this.nSplitter = nSpiltter; kd&~_=Q  
v%`k*n':  
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} m>[G-~0?kI  
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public String getSSiteURL()
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{ p|0SA=?k"  
return sSiteURL; >3p8o@:  
} *hFJI9G  
.{;RJ:O  
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public void setSSiteURL(String value) P%[{
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{ VWXyN  
sSiteURL = value; gQhYM7NP{5  
} c2GTN"  
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public String getSFilePath() S>HfyZ&Pc  
{ -I
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return sFilePath;  W>x.*K  
} Zn|lL0b{q  
{}
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ed/ "OgA  
public void setSFilePath(String value) =y?Aeqq\fl  
{ p*zTuB~e<  
sFilePath = value; @1k-h;`,  
} tnb'\}Vn  
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p  
public String getSFileName() - t4F  
{ \dB z-H'@  
return sFileName; ij_5=4aZ
-  
} !YM:?%B  
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public void setSFileName(String value) |U~\;m@  
{ &u2m6 r>W  
sFileName = value; r5lPO*?Df  
} Fkqw#s(T  
Aba%QQQ  
z+_d*\  
public int getNSplitter() [w FK!?  
{ _lH:%E*  
return nSplitter; @%MGLR{pH  
} ~WmA55  
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public void setNSplitter(int nCount) T%PUV \LV  
{ HXB& 6  
nSplitter = nCount; O+DYh=m*p  
} T!&VT;   
}
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/* A(C0/|#V  
**Utility.java L1SZutWD?  
*/ )5diX + k  
package NetFox; IS{>(XT{  
*MCkezW7{  
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public class Utility { -?)z@L
c  
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public Utility() ; jJ%<  
{ F'@[b   
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} DnB :~&Dw  
\VAS<?3  
//线程睡眠 2;SiH]HNS  
public static void sleep(int nSecond) 8(:O5#  
{ z_$F)*PL  
try{ .k5&C/jv  
Thread.sleep(nSecond); S]c&T`jx  
} ~
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catch(Exception e) ukee.:{  
{ -zm-|6[Wi  
e.printStackTrace (); #.@D}7y5  
} kbx4I?  
} al]-*=v7}  
Cj6$W
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//日志 thh0
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public static void log(String sMsg) AHP;N6Y6  
{ n--s[Kdo8  
System.err.println(sMsg); {k<mN Y  
} ?ieC>cr  
bqZ5GKUo  
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public static void log(int sMsg) D'_w *  
{ 7}fT7tsN  
System.err.println(sMsg); K3J,f2Cn$  
} ? C6tYd  
} E^Z?X2Z  
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 }}d,xI  
/* W
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**TestMethod.java { =IAS}  
*/ E*UE?4FSw|  
package NetFox; ]6?6 k4@  
@t#Ju1Y  
jH2_Ekgc;_  
public class TestMethod { '!XVz$C  
oMb@)7
 
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public TestMethod() Uj)`(}r  
{ ///xx/weblogic60b2_win.exe zhC5%R &n/  
try{ SGLU7*sfd  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,D{D QJ(B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3ZL<6`YF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8]% e[  
fileFetch.start(); J@(69&  
} lD1m<AC  
catch(Exception e){e.printStackTrace ();} <L<d_  
zHQSx7Ow 5  
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} /baSAoh/e
 
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~:"//%M3l  
public static void main(String[] args) KyRcZ"  
{ /qPhptV  
new TestMethod(); ^qNr<Ye  
} YyD0g9{  
} GNI:k{H@"?  
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