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http断点续传简单实现(java)

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/* dE`a1H%  
**SiteFileFetch.java H2plT  
*/ =FB[<%  
package NetFox; l[_ y|W5  
import java.io.*; m#^ua^JV  
import java.net.*; f<$>?o&y  
5vfzSJ  
!sJ*0  
public class SiteFileFetch extends Thread { ;g:!WXd  
!P_8D*^9  
jgz}  
SiteInfoBean siteInfoBean = null; //文件信息Bean Zs$Qo->F  
long[] nStartPos; //开始位置 x+=Ko  
long[] nEndPos; //结束位置 b!h*I>`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9ozK}Cg4  
long nFileLength; //文件长度 i xf~3Y8  
boolean bFirst = true; //是否第一次取文件 =`1#fQDt  
boolean bStop = false; //停止标志 lVw77bZ  
File tmpFile; //文件下载的临时信息 CXe2G5  
DataOutputStream output; //输出到文件的输出流 C`++r>  
sv g`s,g  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) -F-RWs{yS  
public SiteFileFetch(SiteInfoBean bean) throws IOException TN+iv8sT  
{ Q7~9~  
siteInfoBean = bean; r}9a3 1i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /CE]7m,7~K  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3Y L  
if(tmpFile.exists ()) Hju7gP=y}  
{ us_o{  
bFirst = false; U@6bH@v5  
read_nPos(); Ji#"PE/Pt  
} \h#,qTE  
else {D6E@a  
{ kwcH$w<I  
nStartPos = new long[bean.getNSplitter()]; "\n,vNk  
nEndPos = new long[bean.getNSplitter()]; (F<VcB  
} aT]G&bR?  
n{b(~eL?  
CSA.6uIT  
:nt 7jm,  
} YV6@SXy  
"<e<0::  
E!,+#%O>  
public void run() @AvDV$F  
{ ptCFW_UV  
//获得文件长度 IQ5H`o?[B  
//分割文件 cEP!DUo  
//实例FileSplitterFetch hZ#ydI|  
//启动FileSplitterFetch线程 N`G* h^YQ  
//等待子线程返回 1feZ`P ;  
try{ {hXIP`  
if(bFirst) \e=Iw"yd  
{ tiTJ.uz6  
nFileLength = getFileSize(); R.Plfm06Ue  
if(nFileLength == -1) <3 b|Sk:T  
{  wfecM(  
System.err.println("File Length is not known!"); 7M|!N_ $  
} FR7DuH/f)  
else if(nFileLength == -2) DR d|m<Z  
{  Xf4   
System.err.println("File is not access!"); #dvH0LX?  
} )*b dG'}  
else *Y4[YnkPE  
{ FuWMVT`Y  
for(int i=0;i<nStartPos.length;i++) yU e7o4Zm  
{ ^-*q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l@h|os  
} MM+xm{4l  
for(int i=0;i<nEndPos.length-1;i++) &gDwsW  
{ Ew&pwsQ  
nEndPos = nStartPos[i+1]; *FINNNARB  
} efc<lSUR  
nEndPos[nEndPos.length-1] = nFileLength; P  -O& X  
} W -pN  
} TL29{'4V  
sQ)D.9\~  
8RA]h?$$J  
//启动子线程 ;2NJkn9t  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nB~hmE)  
for(int i=0;i<nStartPos.length;i++) jGeil qPC  
{ a5)<roWQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?yfw3s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \),DW)  
nStartPos,nEndPos,i); CQ4MQ<BJ.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 17\5 NgB  
fileSplitterFetch.start(); xrXfLujn%  
} I 3ZlKI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }!&Vcf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); E8Rk b}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ih&rXQ$  
nEndPos = " + nFileLength); /K@_O\+;Q  
// fileSplitterFetch[nPos.length-1].start(); q& :UP  
8)NQt$lWp  
" h D6Z  
//等待子线程结束 feSj3,<!  
//int count = 0; \V1geSoE  
//是否结束while循环 F+c4v A})  
boolean breakWhile = false; H*gX90{!2  
 3ih3O  
8zOoVO  
while(!bStop) DE$HF*WY  
{ _#jR6g TY  
write_nPos(); BE#s@-zR=p  
Utility.sleep(500); o\#C#NiT  
breakWhile = true; *hk8[  
d,hKy2  
!xIK<H{*  
for(int i=0;i<nStartPos.length;i++) J&B>"s,  
{ &F8N$H  
if(!fileSplitterFetch.bDownOver) bh[`uRC}  
{ K KCzq |  
breakWhile = false; nx2iEXsa  
break; vFz#A/1  
} /OX;3" +1  
} vC# *w,  
if(breakWhile) w~3~:w$  
break; y{ ?wxg9  
JKXb$  
mh4<.6>5  
//count++; eB]R<a60  
//if(count>4) =k{ n! e  
// siteStop(); [}GPo0GY  
} &ody[k?'  
M9t`w-@_w  
::lD7@Wg  
System.err.println("文件下载结束!"); wT taj08D  
} A#&,S4Wi|  
catch(Exception e){e.printStackTrace ();} h&k*i  
} Dh4 EP/=z  
'X$J+s}6&  
68!W~%?pR  
//获得文件长度 &4dh$w]q  
public long getFileSize() kT=KxS{  
{ 1 luRTI8^  
int nFileLength = -1; ?}n\&|+  
try{ 19g-#H!  
URL url = new URL(siteInfoBean.getSSiteURL()); qgk-[zW#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %VSjMZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); odm!}stus  
{SQ#n@Q&$  
d:_3V rRZ  
int responseCode=httpConnection.getResponseCode(); )~Pj 3  
if(responseCode>=400) H2cY},  
{ wH<'*>/  
processErrorCode(responseCode); 8iIz!l%O  
return -2; //-2 represent access is error -(Z%?]+  
} 3jJd)C R  
/Cl=;^)  
Gy3t   
String sHeader; d~>d\K%v  
,WA[HwY-  
H[u[3  
for(int i=1;;i++) WlF}R\N!  
{ m|c5X)}-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Cb1fTl%  
//Utility.log(in.readLine()); l)d(N7HME  
sHeader=httpConnection.getHeaderFieldKey(i); x =7qC#+)  
if(sHeader!=null) W pdn^=dhL  
{ p bT sn  
if(sHeader.equals("Content-Length")) ?kF_C,k/>N  
{ m,qMRcDF  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0&W*U{0F\  
break; x,+2k6Wn!  
} )M: pg%  
} 1c2zFBl.&  
else n{@^ne4 m  
break; _P:}]5-|  
} Jq1^}1P  
} 9[9 ZI1*s  
catch(IOException e){e.printStackTrace ();} mjI $z3  
catch(Exception e){e.printStackTrace ();} U7(t >/  
HXg#iP^tv  
fPj*qi  
Utility.log(nFileLength); 9?6]Z ag  
W,53|9b@  
Wb;x eG  
return nFileLength; k/`WfSM\.  
} [3~mil3rO  
0c,)T1NG>  
~R$Ko(N  
//保存下载信息(文件指针位置) pAY[XN  
private void write_nPos() o=}vK[0u  
{  yf/c  
try{  Bm\OH#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sT;:V  
output.writeInt(nStartPos.length); !ot$Q  
for(int i=0;i<nStartPos.length;i++) >~vZ+YO  
{ H*H=a  
// output.writeLong(nPos); _-mJI+^/  
output.writeLong(fileSplitterFetch.nStartPos); Ed^F_Gg#  
output.writeLong(fileSplitterFetch.nEndPos); -:P`Rln  
} E979qKl  
output.close(); $YPQi.  
} x392uS$#  
catch(IOException e){e.printStackTrace ();} jWX^h^n7K  
catch(Exception e){e.printStackTrace ();} :8CYTEc  
} D$vP&7pOr4  
\U\k$ (  
7Gs0DwV  
//读取保存的下载信息(文件指针位置) ;/- X;!a>  
private void read_nPos() KD*q|?Z  
{ q_gsYb  
try{ ,<cF<9h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &# w~S~  
int nCount = input.readInt(); 1^HUu"Kt  
nStartPos = new long[nCount]; Zi4Ektj2  
nEndPos = new long[nCount]; !vQDPLBL  
for(int i=0;i<nStartPos.length;i++) n#fc=L1U  
{ &58TX[#  
nStartPos = input.readLong(); QN'v]z  
nEndPos = input.readLong(); %CaUC'  
} I~f8+DE)  
input.close(); D_(K{? KU  
} 1}#RUqFrvS  
catch(IOException e){e.printStackTrace ();} km[ PbC  
catch(Exception e){e.printStackTrace ();} 28jm*Cl8  
} GO|EeM!iB  
Q =!f,  
2TZ+R7B?  
private void processErrorCode(int nErrorCode) -y1t;yU.L  
{ `JrvD  
System.err.println("Error Code : " + nErrorCode); MV,;l94?%=  
} noLb  
!P"=57d}"l  
v."0igMO  
//停止文件下载 KJ]ejb$  
public void siteStop() s(3iGuT  
{ /EXub U73  
bStop = true; {W5D)  
for(int i=0;i<nStartPos.length;i++) l*0`{R  
fileSplitterFetch.splitterStop(); TXDb5ZCzM  
j1hx{P'  
%x5zs ]4^  
} [ ]LiL;A&  
} j}dev pO  
//负责部分文件的抓取 VJ'bS9/T  
**FileSplitterFetch.java <e%~K4KH  
*/ H5 'Le{  
package NetFox; Dn9AOi!  
/[|ODfY  
=nTNL.SX  
import java.io.*; rcyq+wY #  
import java.net.*; u}L;/1,B  
&8^1:CcE  
GSh~j-C'  
public class FileSplitterFetch extends Thread { i)[8dv  
G._E9  
Dqu][~oQ  
String sURL; //File URL LmA IvEr  
long nStartPos; //File Snippet Start Position 1X45~  
long nEndPos; //File Snippet End Position SA'c}gP  
int nThreadID; //Thread's ID oO 8opS7F  
boolean bDownOver = false; //Downing is over )b_ GKA `  
boolean bStop = false; //Stop identical ::Nhs/B/  
FileAccessI fileAccessI = null; //File Access interface 7Hm/ g  
"k%B;!We)  
9"TPAywd  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #ivN-WKCl  
{ `=B0NC.3  
this.sURL = sURL; j& x=?jX  
this.nStartPos = nStart; ;&9A Yh.  
this.nEndPos = nEnd; *z{.9z`  
nThreadID = id; ?7:?OX  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8pQ:B/3=  
} VSJ08Ngi   
V,W":&!x  
B,]:<1l~  
public void run() ,7{}}l  
{ B2uLfi$q  
while(nStartPos < nEndPos && !bStop) '+Gy)@c  
{ #P''+$5,  
|k-IY]6  
1hT!~'  
try{ *P mk1h2  
URL url = new URL(sURL); Q:+cLl&;hB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OlV'#D   
httpConnection.setRequestProperty("User-Agent","NetFox"); !UV/p"CfX  
String sProperty = "bytes="+nStartPos+"-"; )&$Zt(  
httpConnection.setRequestProperty("RANGE",sProperty); " ~X;u8m  
Utility.log(sProperty); 1~x=bphS  
JnT1-=t.  
@}^eyS$|!  
InputStream input = httpConnection.getInputStream(); T P5?%SlJ  
//logResponseHead(httpConnection); )Fo1[:_B '  
3X,SCG  
=?, dX  
byte[] b = new byte[1024]; tUp'cG  
int nRead; ]DaC??%w  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y8fahQ#  
{ Js7D>GWP!  
nStartPos += fileAccessI.write(b,0,nRead); NSPa3NE  
//if(nThreadID == 1) b[MdA|C%j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hR]AUH  
} 8O)!{gB  
)= ,Lfj8x  
\AT]$`8@_  
Utility.log("Thread " + nThreadID + " is over!"); fy(i<L Z  
bDownOver = true; nOd'$q  
//nPos = fileAccessI.write (b,0,nRead); DsY$  
} _cW (R,i  
catch(Exception e){e.printStackTrace ();} 6.!3g(w   
} H(1( H0Kj"  
} t[.wx.y&0  
G}lP'9/  
Ofyz,% |Q  
//打印回应的头信息 %Ny`d49&  
public void logResponseHead(HttpURLConnection con) #xopJaY  
{ ?B&@  
for(int i=1;;i++) l9 |x7GB  
{ l/JE}Eg(  
String header=con.getHeaderFieldKey(i); <KFE.\*Z4  
if(header!=null) 9J$8=UuxWG  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^lP_{ c  
Utility.log(header+" : "+con.getHeaderField(header)); ?QnVWu2K  
else SnhB$DG  
break; B f_oIc  
} ;bZIj` D(  
} /cy'% .!  
SQZUkKfb  
-%U 15W;  
public void splitterStop() % 1+\N  
{ iE|qU_2Y  
bStop = true; [;Q8xvVZ'  
} 8"#Ix1#  
b$24${*'  
sp0j2<$a  
} &tULSp@J  
}Ot I8;>  
G$5N8k[2  
/* O>E2G]K]\  
**FileAccess.java $hkMJ),T~  
*//文件访问(定位,写) fDn|o"  
package NetFox; o*_O1P  
import java.io.*; CZ/bO#~  
S[b)`Wi D  
9\/T #EP  
public class FileAccessI implements Serializable{ @[qGoai  
Q/%(&4>'y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 EzDj,!!<w  
RandomAccessFile oSavedFile; `J>76WN  
long nPos; {ZS-]|Kx  
&?@gUk74"  
6;lJs,I1w{  
public FileAccessI() throws IOException +G!N@O  
{ $>3/6(bW  
this("",0); #nE%.k|R~  
} z|Hc=AU8y  
FA.h?yfr  
; )Vro  
public FileAccessI(String sName,long nPos) throws IOException %0PdN@I  
{ CWVCYm@!kz  
oSavedFile = new RandomAccessFile(sName,"rw"); _u`NIpXSP  
this.nPos = nPos; s_=/p5\  
oSavedFile.seek(nPos); ~=Y <B/  
} ICD(#m  
hSZ0 }/  
:%dIX}F  
public synchronized int write(byte[] b,int nStart,int nLen) >b |TaQ  
{ UC,43 z  
int n = -1; -}lcMZY  
try{ /`3^?zlu"  
oSavedFile.write(b,nStart,nLen); )p-B@5bb  
n = nLen; r@xMb,!H  
} o b  
catch(IOException e) v5|X=B>&>  
{ kF9T 9  
e.printStackTrace (); ,KlTitJl\+  
} |5wuYG  
g& y R-  
c3gy{:lb  
return n; <By R!Y  
} zfE;)K^"  
aW8Bx\q  
?-g=Rfpag  
} OQ$77]XtvL  
Jlw oSe:S  
{d\erG(  
/* 1n! Jfs U  
**SiteInfoBean.java APT'2 -I_  
*/ T/ CI?sn  
package NetFox; s D] W/  
rsP3?.E  
|H.(?!nTb  
public class SiteInfoBean { q|,I\H5}  
rO% |PRP  
?Uzs^rsb  
private String sSiteURL; //Site's URL "h/{YjUS  
private String sFilePath; //Saved File's Path  J9oGw P  
private String sFileName; //Saved File's Name f[n#Eu}   
private int nSplitter; //Count of Splited Downloading File Y8I$J BO  
WV5gH*uUa  
ex8mA6g  
public SiteInfoBean() P5ii3a?R  
{//nSplitter的缺省值为5 X6mY#T'fQ  
//default value of nSplitter is 5 |X9YVZC  
this("","","",5); K1Tq7/N  
} Eb`U^*A  
A6'G%of  
Urhh)i  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =5EG}@  
{ Ga-AhP  
sSiteURL= sURL; "Hmo`EB0  
sFilePath = sPath; /xjHzva^ w  
sFileName = sName; J{=by]-rD,  
this.nSplitter = nSpiltter; --0z"`@{  
,UQ4`Mh^L  
} XCHoB  
} ;m}lmq,  
da3]#%i0  
$4`RJ{ZJw]  
public String getSSiteURL() _pQ9q&i4  
{ guv)[:cd;  
return sSiteURL; [3s,U4a  
} rMqWXGl`(  
" *xQN "F  
;JpU4W2/  
public void setSSiteURL(String value) wobTT1!|  
{ 9rX[z :  
sSiteURL = value; z3b8  
} od |w)?16  
&yzC\XdA  
x~xaE*r  
public String getSFilePath() t#kR@t+6$\  
{ ?Zu=UVb  
return sFilePath; u0h {bu  
} VAc-RaA  
g% :Q86u  
GmN} +(  
public void setSFilePath(String value) FqiC zP4  
{ w}<BO> z  
sFilePath = value; 7t\W{y  
} h\KQ{-Bl  
]%(hZZ  
:|oH11 y  
public String getSFileName() 3|RfX  
{ )Y@  
return sFileName; ^;GJ7y&,d  
} ecA[  
FsZF>vaV  
^r^c MksB*  
public void setSFileName(String value) `9eE139V='  
{ \1f$]oS  
sFileName = value; .l5y !?  
}  %"j<`  
aYe,5dK>  
pL>Q'{7s3  
public int getNSplitter() ,;C92XY  
{ Ul OoMGg  
return nSplitter; +L*2 6ar6  
} l%lkDh!$"  
0 8vA;6zt  
W,YzD&f=uS  
public void setNSplitter(int nCount) {<&I4V@+  
{ g ZhE\  
nSplitter = nCount; noa?p&Y1m  
} [g/Hf(&  
} !1!;}uzt  
\uQB%yMoz  
A[v]^pv'  
/* t/HMJ  
**Utility.java Uf{cUY,j_  
*/ QvK/31*QG  
package NetFox; V{;Mh u`+  
+Tde#T&[  
BBnbXhxZ  
public class Utility { * 4G J<  
qX`?4"4  
JAen= %2b  
public Utility() ?Jm/v%0O  
{ ]q7\  
or\ 2)  
$I~=t{;"XV  
} Lp20{R  
_Qs )~  
//线程睡眠 /s uz>o\  
public static void sleep(int nSecond) e-H:;m5R  
{ 25*/]i u  
try{ J`;G9'n2  
Thread.sleep(nSecond); ,ju1:`  
} 8$-Wz:X&  
catch(Exception e) MOP %vS   
{ P~iu|j  
e.printStackTrace (); PX52a[wNDH  
} "EF: +gi#"  
} A1Mr  
wx BQ#OE  
//日志 ^o,Hu#  
public static void log(String sMsg) eI; %/6#  
{  gvYa&N  
System.err.println(sMsg); `,Q uO  
} dgE|*1/0  
.l"_f  
c'&3[aa  
public static void log(int sMsg) :}FMauHh  
{ $jo}?Y+  
System.err.println(sMsg); N \[Cuh8Fe  
} Pe!uk4}w  
} CT3wd?)z`  
.RH}/D  
x "]%q^x  
/* 6cVaO@/(  
**TestMethod.java e(x1w&8dB  
*/ /cexd_l|f  
package NetFox; 6GMQgTY^  
CspY+%3$  
V /$qD  
public class TestMethod { .@JXV $Z  
_ mhP:O  
jL^zS XQB  
public TestMethod() G9:[W"P  
{ ///xx/weblogic60b2_win.exe prb;q~  
try{ 20d[\P(.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f8+($Ys  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); L{N9h1]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); KR%p*Nh+C  
fileFetch.start(); HviL4iO  
} >&RpfE[  
catch(Exception e){e.printStackTrace ();} \gki!!HQ  
Nj*J~&6G  
U: ~O^  
} Xgn^)+V:  
5@P2Z]Q  
\;I%>yOIu  
public static void main(String[] args) >e($T!}Z  
{ :g}WN  
new TestMethod(); Ui@Q&%b  
} ,E$^i~OO  
} X_Is#&6;  
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