http断点续传简单实现（java)

/* &?QKWxN  
**SiteFileFetch.java Pl'lmUR  
*/ E.m2- P;4  
package NetFox; >wqWIw.w>  
import java.io.*; +7
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import java.net.*; ?H_@/?  
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public class SiteFileFetch extends Thread { 4>d]0=x  
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SiteInfoBean siteInfoBean = null; //文件信息Bean sSKD"  
long[] nStartPos; //开始位置 )UU`uzU;u  
long[] nEndPos; //结束位置 B=W#eu <1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]]r;}$  
long nFileLength; //文件长度 j-/$e,xX  
boolean bFirst = true; //是否第一次取文件 uYlyU~M:D  
boolean bStop = false; //停止标志 m=h/A xW  
File tmpFile; //文件下载的临时信息 !sI^Lh,Y  
DataOutputStream output; //输出到文件的输出流 jt6_1^   
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &k*oG:J3  
public SiteFileFetch(SiteInfoBean bean) throws IOException ImB5F'HI$  
{ )g8Kicox5  
siteInfoBean = bean; $HOe){G  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Q$p3cepsK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;8MQ'#  
if(tmpFile.exists ()) )Dhx6xM[a  
{ ~FAk4
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bFirst = false; =YO<.(Lu  
read_nPos(); NoF|j57?u'  
} B)DuikV.D  
else nvQX)Xf  
{ R!"`Po  
nStartPos = new long[bean.getNSplitter()]; I+Yq",{%  
nEndPos = new long[bean.getNSplitter()]; c]k+ Sx&}  
} HI:
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} *=O3kUoL  
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public void run() 4yTgH0(T  
{ R9-mq;u+  
//获得文件长度 p {.6  
//分割文件 fbdpDVmpU  
//实例FileSplitterFetch I4
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//启动FileSplitterFetch线程 H^o_B1  
//等待子线程返回 @>ys,dy  
try{ k&[6Ld0~56  
if(bFirst) W"\`UzOLQ  
{
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nFileLength = getFileSize(); 5sEk rT '  
if(nFileLength == -1) ep5`&g]3  
{ ^(T~Qp  
System.err.println("File Length is not known!"); [q0^Bn}h  
} ,bM):  
else if(nFileLength == -2) <h+UC# .x  
{ ntPX?/  
System.err.println("File is not access!"); N2j^fZd_  
} WCqa[=v)t  
else _ A{F2M  
{ !%(kMN  
for(int i=0;i<nStartPos.length;i++) 9RSviIi$  
{ EcytNYn  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I%Z=O=  
} b!J?>du  
for(int i=0;i<nEndPos.length-1;i++) i&\ >/ 1  
{ inq {" 6  
nEndPos = nStartPos[i+1]; eq"Xwq*  
} vqoK9  
nEndPos[nEndPos.length-1] = nFileLength; 8ZjRMr}  
} `{IL.9M!f  
} ' qT\I8%  
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//启动子线程 |#x
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3H>\hZ  
for(int i=0;i<nStartPos.length;i++) G<rAM+B*g  
{ dqgr98  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &+hk5?c /  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F4V) 0)G  
nStartPos,nEndPos,i); +_*iF5\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M
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fileSplitterFetch.start(); iW9  
} 6h&t%T  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \v{HjqVkC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); QAl4w)F  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6N Ogi  
nEndPos = " + nFileLength); bQN3\mvY  
// fileSplitterFetch[nPos.length-1].start(); )L":I  
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!"E/6z2&(k  
//等待子线程结束 9G7Brs:  
//int count = 0; Bz%wV-  
//是否结束while循环 Wi\k&V
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boolean breakWhile = false; \fvm6$ rZ^  
^rY18?XC+:  
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while(!bStop) ]70ZerQ~L  
{ &VCg`r-{~  
write_nPos(); EKQ>hww8  
Utility.sleep(500); )@tHS-Jf  
breakWhile = true; -~_|ZnuM9  
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for(int i=0;i<nStartPos.length;i++) y La E]  
{ Be\@n xV[  
if(!fileSplitterFetch.bDownOver) Jko=E   
{  Bw+?MdS  
breakWhile = false; :7Uv)@iUk  
break; fceO|mSz_  
} qf@P9M  
} vwa*'C  
if(breakWhile) j`Ek:  
break; ]|K6Z>V  
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//count++; f?16%Rk<  
//if(count>4) (m2_Eh;  
// siteStop(); ?h|DeD!s  
} [yc7F0Aw  
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System.err.println("文件下载结束！"); (KPD`l8.  
} oe<@mz/  
catch(Exception e){e.printStackTrace ();} X(#8EY}X  
} yVKl%GO  
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*L Y6hph"  
//获得文件长度 OOABn*  
public long getFileSize() Fs=)*6}&  
{ <{YzmN\Z  
int nFileLength = -1; Ty7`&  
try{ FKhgUnw  
URL url = new URL(siteInfoBean.getSSiteURL()); @FF{lK?[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ofI,[z3  
httpConnection.setRequestProperty("User-Agent","NetFox"); sint":1FC  
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int responseCode=httpConnection.getResponseCode(); 3Tw9Uc\vT  
if(responseCode>=400) cT&lkS  
{ O69TU[Vn  
processErrorCode(responseCode); ~*^o[~x]\  
return -2; //-2 represent access is error 0xvSi9  
} %uiCC>cC  
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String sHeader; MJH>rsTQ  
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for(int i=1;;i++) -QBM^L  
{ ;K4uu<e\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6o(.zk`d  
//Utility.log(in.readLine()); /t2H%#v{  
sHeader=httpConnection.getHeaderFieldKey(i); *Utx0Me  
if(sHeader!=null) 2FO<Z %Y  
{  (wxi!  
if(sHeader.equals("Content-Length")) n!Y}D:6c6  
{ xbHI4A"Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); X%B$*y5  
break; e5;YY  
} +br' 2Pn  
} JP^
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else $GhL-sqm  
break; 1>2 /1>  
} S&'s/jB  
} KilN`?EJ  
catch(IOException e){e.printStackTrace ();} Znh;#%n|  
catch(Exception e){e.printStackTrace ();} Y9st3  
9U )9u["DH  
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Utility.log(nFileLength); )!G
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return nFileLength; \.P#QVuQ  
} :w4N*lV-  
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//保存下载信息（文件指针位置） *o(bB!q"c  
private void write_nPos() g1l:k1\Ht  
{ G$CSZrP.  
try{ \-[ >bsg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); lKqFuLHwF  
output.writeInt(nStartPos.length); 4&:|h 1  
for(int i=0;i<nStartPos.length;i++) =n@\m<  
{ W,!7_nl"u  
// output.writeLong(nPos); i!(5y>I_  
output.writeLong(fileSplitterFetch.nStartPos); x~D8XN{  
output.writeLong(fileSplitterFetch.nEndPos); 2<'ol65/c  
} :eevc7  
output.close(); R4DfqX  
} NMrf I0tbG  
catch(IOException e){e.printStackTrace ();} "st+2#{  
catch(Exception e){e.printStackTrace ();} txX>zR*)  
} Z\n^m^Z =  
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//读取保存的下载信息（文件指针位置） 4gmlK,a  
private void read_nPos() g2u\gR5  
{ yKm6 8n^  
try{ I58$N+#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); IfI:|w}:"r  
int nCount = input.readInt(); 8&qtF.i-6  
nStartPos = new long[nCount]; *
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nEndPos = new long[nCount]; x7jFYC  
for(int i=0;i<nStartPos.length;i++) %ca`v;].  
{ 6J$I8b#/  
nStartPos = input.readLong();
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nEndPos = input.readLong(); P/q] u  
} g$/7km{TP  
input.close(); pRjrMS  
} wMCgLh\wi  
catch(IOException e){e.printStackTrace ();} ;W\?lGOs{  
catch(Exception e){e.printStackTrace ();} 6UqDpL7^U  
} 13Q87i5B  
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=
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private void processErrorCode(int nErrorCode) G}}Lp
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{ sEL0h4  
System.err.println("Error Code : " + nErrorCode); |fgh ryI,  
} #hXvGon
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//停止文件下载 :j/sTO=  
public void siteStop() (>lH=&%zj  
{ OcC|7s",  
bStop = true; u6MU @?  
for(int i=0;i<nStartPos.length;i++) MvaX>n!o  
fileSplitterFetch.splitterStop(); >m%7dU  
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} cXYE!(  
} GR 1%(,  
//负责部分文件的抓取 Cyo:Da A  
**FileSplitterFetch.java Y'+KU/H  
*/ x>T+k8[n  
package NetFox; i]qxF&1  
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import java.io.*; .}(X19R  
import java.net.*; 3hA5"G+7  
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public class FileSplitterFetch extends Thread { n+2>jY  
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String sURL; //File URL Kt/:caD  
long nStartPos; //File Snippet Start Position RfT)dS+rAh  
long nEndPos; //File Snippet End Position y,qn9  
int nThreadID; //Thread's ID LIyb+rH#yg  
boolean bDownOver = false; //Downing is over wk1/&  
boolean bStop = false; //Stop identical W
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FileAccessI fileAccessI = null; //File Access interface zp``e;gY  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^U,Dx  
{ gplrJaH@  
this.sURL = sURL; Ev3,p`zS._  
this.nStartPos = nStart; 7m:TY>{  
this.nEndPos = nEnd; nXjSf  
nThreadID = id; }n"gX>e~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BhiOV_}Hn  
} :" JEC'  
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public void run() j^h:*rw  
{ {*<%6?  
while(nStartPos < nEndPos && !bStop) 82o|(pw  
{ sNMF(TY  
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try{ ,8!'jE[d  
URL url = new URL(sURL); 
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `-?`H>+OG  
httpConnection.setRequestProperty("User-Agent","NetFox"); '#Do( U'  
String sProperty = "bytes="+nStartPos+"-"; J\J3'u  
httpConnection.setRequestProperty("RANGE",sProperty); P=s3&NDD  
Utility.log(sProperty); 4`Jf_C  
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InputStream input = httpConnection.getInputStream(); E;q+u[$  
//logResponseHead(httpConnection); >T{TE"XyO|  
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byte[] b = new byte[1024]; DV)NY!  
int nRead; 8~BLTZ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |A+,M"F?  
{ J-5kvQi8  
nStartPos += fileAccessI.write(b,0,nRead); e-VGJ
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//if(nThreadID == 1) 7=&+0@R#/d  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;*=7>"o'`  
} %CUwD  
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Utility.log("Thread " + nThreadID + " is over!"); DUg[L
 
bDownOver = true; 9`KFJx6D  
//nPos = fileAccessI.write (b,0,nRead); b S'dXP  
} $0+&xJVn  
catch(Exception e){e.printStackTrace ();} }U%T6~_wR  
} c}H}fyu%n  
} QC6QqcOX  
]!s@FKC{;  
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//打印回应的头信息 z<J2e^j  
public void logResponseHead(HttpURLConnection con) [lu+"V,<LJ  
{ X}ihYM3y/  
for(int i=1;;i++) U_Q;WPJ  
{ cxx8I  
String header=con.getHeaderFieldKey(i); '+c@U~d*7  
if(header!=null) lAo4)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y3-f68*(  
Utility.log(header+" : "+con.getHeaderField(header)); aEun *V^,  
else . K_Jg$3  
break; 1{1mL-I;  
} 9Sl5jn  
} bkrl>Im<n  
. +,{|){c  
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public void splitterStop() +6^hp-G7  
{ 6 B7F  
bStop = true; mXyg\5  
} q%,y66pFr  
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} C^:{y  
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/* v] m`rV8S[  
**FileAccess.java EiyHZ  
*//文件访问(定位，写) <q&i"[^M  
package NetFox; %_~1(Glz  
import java.io.*; {!!8 *ix  
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public class FileAccessI implements Serializable{ VZ7E#z+nM#  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3T[zieX  
RandomAccessFile oSavedFile; czB),vooz  
long nPos; b'vIX< g  
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public FileAccessI() throws IOException /J(~NGT  
{ ;1>V7+/  
this("",0); ZmJ<FF4  
} OM`Ws5W}f  
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public FileAccessI(String sName,long nPos) throws IOException Cm0K-~ U  
{ FV/lBWiQQ  
oSavedFile = new RandomAccessFile(sName,"rw"); _<l)4A3rS  
this.nPos = nPos; o WAy[  
oSavedFile.seek(nPos); FtDF
}  
} 3FMYs&0r4  
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public synchronized int write(byte[] b,int nStart,int nLen) E 0@u|  
{ ]Y$jc  
int n = -1; m';4`Y5-  
try{ AtqsrYj  
oSavedFile.write(b,nStart,nLen); :4LWm<P  
n = nLen; l7Wdbx5x0  
} M<SVH_  
catch(IOException e) =NWzsRl,  
{ tJm1Q#||  
e.printStackTrace (); ):n'B` f}z  
} Dv4H^  
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return n; N9u {)u  
} 4E$d"D5]>p  
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} K?yMy,9%Yw  
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/* V@\u<LO0G  
**SiteInfoBean.java c<{~j~+  
*/ cs[n
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package NetFox; *q@3yB}  
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public class SiteInfoBean { R_vK^Da  
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private String sSiteURL; //Site's URL vtc%MG1  
private String sFilePath; //Saved File's Path Ga pM~~  
private String sFileName; //Saved File's Name /!60oV4p0  
private int nSplitter; //Count of Splited Downloading File Q@*9|6-  
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public SiteInfoBean() a%QgL&_5  
{//nSplitter的缺省值为5 lXD=uRCI  
//default value of nSplitter is 5 .sb0|3&  
this("","","",5); M[e^Z}w.V  
} b27t-p8  
+;bZ(_ohG  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'CRjd~L  
{ []?*}o5&>T  
sSiteURL= sURL; G\(*z4@Gz  
sFilePath = sPath; dki3(  
sFileName = sName; V|<'o<h8  
this.nSplitter = nSpiltter; lQ4$d{m`  
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} $- Y8@bw  
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public String getSSiteURL() \vuWypo  
{ .s|5AC[  
return sSiteURL; q77Iq0VR  
} Pu'lp O  
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public void setSSiteURL(String value) ZbH_h]1$D  
{ ('.I)n  
sSiteURL = value; 51ILR9 Bc_  
} (.b!kfC  
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public String getSFilePath() rY$wC%  
{
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return sFilePath; V2g"5nYT  
} \\Z?v,XsS  
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public void setSFilePath(String value) &0{&4,  
{ BT f  
sFilePath = value; |Vp ?  
} `*]r+J2  
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public String getSFileName() YDgG2hT/2  
{ 2Ic)]6z R  
return sFileName; CYM>4C~>JW  
} e'fo^XQn[  
6 I43a1[s  
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public void setSFileName(String value) R0F&!y!B  
{ *~.'lE%[U  
sFileName = value; ~x J#NC+  
} Xod/GYG  
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public int getNSplitter() s1X?]A  
{ ^xr &E  
return nSplitter; m,F4N$  
} 59V8cO+qH  
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public void setNSplitter(int nCount) hl8oE5MU  
{ >&T J  
nSplitter = nCount; semTAoqH  
} %xC}#RDf  
} 6f+@@=Xc  
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hl,x|.f}4Y  
/* `J;g~#/k  
**Utility.java 1TgD;qX  
*/ |w>d]eA5  
package NetFox; '1Ex{

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public class Utility { G}nj 71=H  
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public Utility() gj }Vnv1[  
{ xk^`4;  
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} Z/OERO   
V\AF%=6}  
//线程睡眠 Z0M|Bv9_  
public static void sleep(int nSecond) fyq%-Tj  
{ .RbPO#(  
try{ O81'i2MJ9  
Thread.sleep(nSecond); "~"=e  
} <V|\yH9  
catch(Exception e) 9zpOp-K6  
{ f2ck=3  
e.printStackTrace (); m-Se-aF  
} bc2S?u{  
} 6dRvx;d  
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//日志 - P4X@s_;  
public static void log(String sMsg) 5&]a8p{  
{ ?VyiR40-Cx  
System.err.println(sMsg); T5_rPz  
} _t6.9CXl  
mzf^`/NO  
P+rDln{  
public static void log(int sMsg) PE6ZzxR|U<  
{ BD mF+  
System.err.println(sMsg); P[H 4Yp  
} 4u1au1c  
} BD M
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/* Z_Y gV:jc  
**TestMethod.java _ujhD  
*/ hh-sm8  
package NetFox; 9Wdx"g52_D  
r$,Xv+}  
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public class TestMethod { mD,fxm{G  
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public TestMethod() L(HAAqRn
J  
{ ///xx/weblogic60b2_win.exe 5$*=;ls>J  
try{ ~vMJ?P@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); zSBR_N51  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2rM/kF >g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); IG!(q%Gf  
fileFetch.start(); y`pgJO  
} {7EpljH@  
catch(Exception e){e.printStackTrace ();} w%%*3[--X  
J #;|P-pt  
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} w|-m*v .  
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12}!oS~_  
public static void main(String[] args) j!IkU}*c  
{ &HqBlRo  
new TestMethod(); |zy` ]p9  
} z:A_  
} :VX2&*  
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