http断点续传简单实现（java)

/* VYkOJAEBg  
**SiteFileFetch.java /ZZo`   
*/ >|!F.W  
package NetFox; E#r6e+e1Q%  
import java.io.*; _)Q)tOW  
import java.net.*; ed4:r/Dpo  
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public class SiteFileFetch extends Thread { QIF|pZ+^  
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SiteInfoBean siteInfoBean = null; //文件信息Bean |
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long[] nStartPos; //开始位置 rOw""mE  
long[] nEndPos; //结束位置 !HL7a]PB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (;P)oB"`C  
long nFileLength; //文件长度 0G1?  
boolean bFirst = true; //是否第一次取文件 .MMFN}1O  
boolean bStop = false; //停止标志 Hv(0<k6oH  
File tmpFile; //文件下载的临时信息 jDIO,XuF  
DataOutputStream output; //输出到文件的输出流 |Y"q. n77  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） FGu:8`c9  
public SiteFileFetch(SiteInfoBean bean) throws IOException VdQ}G!d  
{ +4f>njARIb  
siteInfoBean = bean; Bvzl* &?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); q$e2x=?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); EcrM`E#kaZ  
if(tmpFile.exists ())
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{ 6ND,4'6  
bFirst = false; Zalgg/.  
read_nPos(); -}1S6dzr  
} 5Tluxt71  
else XP *pYN  
{ S*Scf~Qp  
nStartPos = new long[bean.getNSplitter()]; T[B@7$Dp*  
nEndPos = new long[bean.getNSplitter()]; 4%~$A`7  
} &Eg>[gAIlp  
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} zg2A$Fd[j  
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public void run() P!:Y<p{=>  
{ TAlpy$  
//获得文件长度 &K2[>5 mG  
//分割文件 F.ryeOJ  
//实例FileSplitterFetch B;Ab`UX#t  
//启动FileSplitterFetch线程 5WgdgDb@L  
//等待子线程返回 pbKDtqSnz  
try{ Teu4;  
if(bFirst) |[(4h  
{ pL8
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nFileLength = getFileSize(); E.Xfb"]  
if(nFileLength == -1) a h>k=t8(  
{ QgO@oV*S  
System.err.println("File Length is not known!"); {^>m3  
} JYOyz+wNd  
else if(nFileLength == -2) j':Ybr>BR  
{ )Xg,;^  
System.err.println("File is not access!"); H>_ FCV8  
} A>(m}P  
else n c:^)G  
{ &N GYV  
for(int i=0;i<nStartPos.length;i++) sh[Yu  
{ 7g}4gX's  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); FYR%>Em  
} %50}oD@  
for(int i=0;i<nEndPos.length-1;i++) P}N%**>`  
{ a{^[<  
nEndPos = nStartPos[i+1]; HiCNs;t  
} o{pQDI {R  
nEndPos[nEndPos.length-1] = nFileLength; 96T.xT>&  
} >w+WG0Z K  
} ]S<eO6z  
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//启动子线程 \NKf$"x}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; '
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for(int i=0;i<nStartPos.length;i++) j0^~="p%C  
{ n(l!T 7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |4aV~n[>#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~V[pu  
nStartPos,nEndPos,i); %sP C3L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )+RTA y[k  
fileSplitterFetch.start(); 1O*5>dkX;%  
} $wH{snX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;0O3b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); q]YPDdR#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8hba3L_Z  
nEndPos = " + nFileLength); 4]A2Jl E  
// fileSplitterFetch[nPos.length-1].start(); |8PUmax
 
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//等待子线程结束 z:-a7_  
//int count = 0; W_
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//是否结束while循环 vt<r_&+ pJ  
boolean breakWhile = false; W,5A|Q~  
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5:/ zbt\C  
while(!bStop) I!&|L0Qq  
{ )9MmL-7K  
write_nPos(); T^g2N`w2  
Utility.sleep(500); I-oI,c%+  
breakWhile = true; >(S4h}^
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for(int i=0;i<nStartPos.length;i++) 2s>dlz  
{ f9u^/QVS&  
if(!fileSplitterFetch.bDownOver) /:d03N\9k  
{ _fha9`  
breakWhile = false; ewg&DBbN"  
break; .^j#gE&B  
} >Lp^QP1gU  
} 2ikY
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if(breakWhile) -hj@^Auf  
break; #Mw|h^Wm  
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//count++; |E-/b6G  
//if(count>4) Vd~{SS2>  
// siteStop(); Hq[d!qc  
} )kR~|Yn<-  
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System.err.println("文件下载结束！"); JUXIE y^  
} Q*}#?g  
catch(Exception e){e.printStackTrace ();} P1)f-:;  
} EKoAIC*?p  
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//获得文件长度 l|z 'Lwwm5  
public long getFileSize() %5V!Fdb  
{ ['ol
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int nFileLength = -1; Wm$(b2t  
try{ N|K,{ p^li  
URL url = new URL(siteInfoBean.getSSiteURL()); Q1J./C}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eWzD'3h^  
httpConnection.setRequestProperty("User-Agent","NetFox"); H7n5k,  
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int responseCode=httpConnection.getResponseCode(); /1 lIV_Z  
if(responseCode>=400) s `fIeP  
{ u,e'5,`N  
processErrorCode(responseCode); P3V=DOG"  
return -2; //-2 represent access is error BV,P;T0"D  
} Cv862kP  
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String sHeader; BoZ])Y6=  
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for(int i=1;;i++) ?;@xAj  
{ x4|>HY<p?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h1@|UxaE#  
//Utility.log(in.readLine()); }[XzM/t  
sHeader=httpConnection.getHeaderFieldKey(i); k<RJSK8  
if(sHeader!=null) .WM0x{t/  
{ w^MU$ubx  
if(sHeader.equals("Content-Length")) }MAQhXI^O|  
{ y>wrm:b-O  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); B5h-JON]-  
break; ^(y=DJ7  
} ks|[`FH  
} BqC, -gC  
else S6CM/  
break; =S/$h}Vi  
} maQE Bi,  
} }YJ(|z""  
catch(IOException e){e.printStackTrace ();} 3"=%[  
catch(Exception e){e.printStackTrace ();} 0jCYOl  
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Utility.log(nFileLength); YfL|FsCh  
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return nFileLength; Fgq"d7`9@  
}
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//保存下载信息（文件指针位置） 1];rW`Bw  
private void write_nPos() N"MK 0k  
{ cAq>|^f0a  
try{ hNBv|&D#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <![tn#_  
output.writeInt(nStartPos.length); u4TU"r("A  
for(int i=0;i<nStartPos.length;i++) oT2h'gu")  
{ KtzoL#CT  
// output.writeLong(nPos); -5,QrMM<  
output.writeLong(fileSplitterFetch.nStartPos); @w&VI6  
output.writeLong(fileSplitterFetch.nEndPos); p48M7OV  
} 0STtwfTr:  
output.close(); XH4!|wz  
} `&$"oW{HW  
catch(IOException e){e.printStackTrace ();} )1ia;6}  
catch(Exception e){e.printStackTrace ();} JwWW w1  
} *0]E4]ZO  
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//读取保存的下载信息（文件指针位置） S|!)_RL  
private void read_nPos() a@`15O:  
{ |_L\^T|6  
try{ !xm
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); WccTR aq  
int nCount = input.readInt(); `<&RZB2  
nStartPos = new long[nCount]; cPA-EH  
nEndPos = new long[nCount]; Pk/{~!+ $  
for(int i=0;i<nStartPos.length;i++) *A C){M  
{ dr0<K[S_  
nStartPos = input.readLong(); <>/0;J1<  
nEndPos = input.readLong(); PD$XLZ  
} z=1 J{]  
input.close(); 'qcLK>E  
} nEu,1  
catch(IOException e){e.printStackTrace ();} h|OqM:J
;  
catch(Exception e){e.printStackTrace ();} -1).'aJ^  
} N*z_rZE  
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private void processErrorCode(int nErrorCode) q<(yNqMKP  
{ [uCW8:e  
System.err.println("Error Code : " + nErrorCode); =H&{*Ja  
} 8 tMfh  
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^FNvVbK|`  
//停止文件下载 5&a4c"fU  
public void siteStop() i zJa`K  
{ mh`~1aEr  
bStop = true; Eukj2a  
for(int i=0;i<nStartPos.length;i++) )RA$E`!b  
fileSplitterFetch.splitterStop(); ]la8MaZ<  
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} $g&,$7}O_  
} Ut:>'TwG  
//负责部分文件的抓取 lc1?V
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**FileSplitterFetch.java l/9V59Fv9  
*/ ,'[L6=#  
package NetFox; |uo<<-\jTO  
)]x/MC:9r  

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import java.io.*; sYnf #'  
import java.net.*; XnC`JO+7M  
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public class FileSplitterFetch extends Thread { ?K,xx
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String sURL; //File URL `s HrC  
long nStartPos; //File Snippet Start Position ZuZe8&  
long nEndPos; //File Snippet End Position yZ?|u57  
int nThreadID; //Thread's ID [1{#a
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boolean bDownOver = false; //Downing is over MX!t/&X(n  
boolean bStop = false; //Stop identical 1_JtD|Jy  
FileAccessI fileAccessI = null; //File Access interface df@IC@`pB  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1haH2F^q3  
{ XBQ]A89G  
this.sURL = sURL; lx9tUTaus/  
this.nStartPos = nStart; <aps)v
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this.nEndPos = nEnd; o&45y&  
nThreadID = id; =#)Zm?[;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +~~FfIzf#  
} HPl'u'.Hg  
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public void run() s5{N+O)~S  
{ Fw,'a  
while(nStartPos < nEndPos && !bStop) g/H:`J
  
{ <vS J<WY  
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try{ ,>(/}=Z.  
URL url = new URL(sURL); r|!w,>.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9MfBsp}c  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5!
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String sProperty = "bytes="+nStartPos+"-"; {m1=#*  
httpConnection.setRequestProperty("RANGE",sProperty); p.{9OrH(4  
Utility.log(sProperty); r&F(VF0 6  
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InputStream input = httpConnection.getInputStream(); eu!B ,  
//logResponseHead(httpConnection); Fkgnc{NI  
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byte[] b = new byte[1024]; WjfUbKg0  
int nRead; r![RRa^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j2GO ZKy  
{ J:6wFmU  
nStartPos += fileAccessI.write(b,0,nRead); bb<qnB  
//if(nThreadID == 1) _86pbr9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,S"a ,}8  
} PF$K> d  
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Utility.log("Thread " + nThreadID + " is over!"); qRXQL"Pe_l  
bDownOver = true; l :sZ  
//nPos = fileAccessI.write (b,0,nRead); Z}#,E;  
} Q-<,+[/  
catch(Exception e){e.printStackTrace ();} s)_Xj
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} V}?d ,.m`{  
} )$18a  
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//打印回应的头信息 8?ig/HSt2  
public void logResponseHead(HttpURLConnection con) C@!C='b,  
{ z}I4m  
for(int i=1;;i++) e[txJ*SuO  
{ x!6&)T?!n  
String header=con.getHeaderFieldKey(i); U@#YKv  
if(header!=null) =4RXNWkud  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); x13t@b  
Utility.log(header+" : "+con.getHeaderField(header)); kpc3l[.A  
else
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break; ?6h65GO{  
} WzM9{c  
} C$MaJHkiF  
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public void splitterStop() ?m&?BsW$)  
{ /S}0u}jID?  
bStop = true; wps`2`z  
} EL_rh TWw  
i <KWFF#  
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} sT|$@$bN  
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/* {d`e9^Z:  
**FileAccess.java S+c)  
*//文件访问(定位，写) ~udi=J|  
package NetFox; b"U{@  
import java.io.*; ')pXQ  
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public class FileAccessI implements Serializable{ yKJKQ9  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |eD$eZ=m  
RandomAccessFile oSavedFile; j=U [V&T  
long nPos; Q;p?.GI?-  
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public FileAccessI() throws IOException IooAXwOF  
{  3*@ sp  
this("",0); r^3QDoy  
} %'2DEt??  
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#
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public FileAccessI(String sName,long nPos) throws IOException <5qXC.{Cyp  
{ 0@w8,x  
oSavedFile = new RandomAccessFile(sName,"rw"); :r0?[#r?N,  
this.nPos = nPos; m.ib#Y)y  
oSavedFile.seek(nPos); y%.^| G  
} an+`>}]F  
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public synchronized int write(byte[] b,int nStart,int nLen) HCP'V  
{ ~Yrtz  
int n = -1; }Dk*Hs^E  
try{ Ns.b8Y  
oSavedFile.write(b,nStart,nLen); S{cy|QD  
n = nLen; c(@V t&gE  
} fVCpG~&t  
catch(IOException e) w_-v!s2  
{ }S{#DgZ@X  
e.printStackTrace (); RhVQV
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} fp^!?u  
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return n; Y.M^tH:  
} xA|72!zk0P  
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} YGVj$\  
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/* 96fzSZS,  
**SiteInfoBean.java LfD70r\  
*/ YXCfP
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package NetFox; 9I0}:J;7  
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public class SiteInfoBean { qsnZ?hXPp  
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private String sSiteURL; //Site's URL B4k~~;|  
private String sFilePath; //Saved File's Path `9;:mR $  
private String sFileName; //Saved File's Name ^6=y4t=%F  
private int nSplitter; //Count of Splited Downloading File Y*
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public SiteInfoBean() {"<D$*K~  
{//nSplitter的缺省值为5 vu^ '+ky  
//default value of nSplitter is 5 @dimZsi1  
this("","","",5); . IBy'  
} Ii"h:GY;\  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'UGkL;  
{ _hgu:  
sSiteURL= sURL; sqkk4w1#C  
sFilePath = sPath; uveby:dh  
sFileName = sName; {[V<mT2/  
this.nSplitter = nSpiltter; /]~Oa#SQ:  
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} G]Fp},  
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public String getSSiteURL() @ i$jyc  
{ ;eYm+e^?.  
return sSiteURL; ~>:uMXyV2t  
} (=n{LMa  
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public void setSSiteURL(String value) 'l,ym~R  
{ B5'-v%YO+  
sSiteURL = value; v8Ga@*  
} F91'5D,u0  
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public String getSFilePath() `w@8i[2J  
{ &)4#0L4  
return sFilePath; E! '|FJ  
} X 4\  
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public void setSFilePath(String value) .W[ 9G\  
{ hV,)u3  
sFilePath = value; %fY\vd2  
} Y.9s-g  
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public String getSFileName() oWg"f*  
{ V/C":!;  
return sFileName; E1)7gio  
} ygiZ~v4P/  
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public void setSFileName(String value) 6_`9 4+  
{ QDO.
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sFileName = value; 9F[k;Uw  
} ^Ec);Z  
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public int getNSplitter() `ceetr=  
{ D?yiK=:08`  
return nSplitter; X=QaTV  
} q~QB?+ x&  
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public void setNSplitter(int nCount) %ZT@&  
{ 3iKBVN  
nSplitter = nCount; v(5zSo  
} ^! ?wh  
} ma__LWKM,  
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/* N@Fof(T&  
**Utility.java OAGI|`E$/-  
*/ C!a
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package NetFox; *^|.bBG  
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public class Utility { {<f |h)r  
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public Utility() [nL{n bli  
{ u">KE6um  
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} s/' ]* n  
v[P $c$Xi  
//线程睡眠 P
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public static void sleep(int nSecond) {,kA'Px)  
{ )#|I(Gz ^  
try{ NR </Jm*  
Thread.sleep(nSecond);  D`Tx,^E  
} ~yrEB:w`_  
catch(Exception e) yL ?dC"c  
{ xA?(n!{P  
e.printStackTrace (); /j}"4_.8  
} >ZX&2 {
 
} 2h:*lV^  
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//日志 >)V1aLu=  
public static void log(String sMsg) YfB8  
{ QC/%|M0 {  
System.err.println(sMsg); >St]MS
 
} \piHdVD  
,\2w+L5TD  
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public static void log(int sMsg) Zt3Y<3o  
{ }iOFB&)w  
System.err.println(sMsg); 3rRN~$  
} +;@p'af!9  
} f9ziSD#  
P LHiQ:  
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/* h_xHQf&#  
**TestMethod.java xna4W|-  
*/ yu^n;gWH  
package NetFox; "2J$~2{N  
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public class TestMethod { 3Gr:.V9=  
*=b#>//  
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public TestMethod() Qj:`[#3?2  
{ ///xx/weblogic60b2_win.exe 5Xe1a'n5]  
try{ .|Ee,Un  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Y2Z<A(W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N,oN3mFF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); O4l]Q  
fileFetch.start(); "q<}#]u  
} UoD@ix&0  
catch(Exception e){e.printStackTrace ();} b~5Q|3P9  
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}
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public static void main(String[] args) ZJZKCdT@  
{ 06r-@iY.]  
new TestMethod(); Zo12F**{  
} @+iO0?f  
} v +$3Z5  
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