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http断点续传简单实现(java)

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/* >HX)MwAP  
**SiteFileFetch.java T(gg>_'jh  
*/ fQ1 0O(`g,  
package NetFox; 9ClF<5?M  
import java.io.*; ,$ mLL  
import java.net.*; I^@.Aw t  
mQL8QW[c  
s6IP;}  
public class SiteFileFetch extends Thread { 5)8 .  
0NrTJ R`  
&<@%{h@=  
SiteInfoBean siteInfoBean = null; //文件信息Bean smbUu/  
long[] nStartPos; //开始位置 k0knPDbHv  
long[] nEndPos; //结束位置 (qbc;gBy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 UC(9Dz  
long nFileLength; //文件长度 Stt* 1gT  
boolean bFirst = true; //是否第一次取文件 MorW\7-}  
boolean bStop = false; //停止标志 IX?@~'  
File tmpFile; //文件下载的临时信息 egbb1+tY  
DataOutputStream output; //输出到文件的输出流 OFQ{9  
\wFhTJY  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) C-&#r."L  
public SiteFileFetch(SiteInfoBean bean) throws IOException K]9tc)  
{ rCkYfTYI  
siteInfoBean = bean; }.OxJ=M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h>.9RX &  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p#z;cjfSt  
if(tmpFile.exists ()) \DaLHC~  
{ bYK]G+Ww  
bFirst = false; hg{ &Y(J!U  
read_nPos(); M{G$Pk8[  
} uFWvtL?;_  
else lR, G;  
{ YyG~#6aCh  
nStartPos = new long[bean.getNSplitter()]; A=W5W5l(>  
nEndPos = new long[bean.getNSplitter()]; Na-q%ru  
} Up'."w_zE  
XQ4dohGCP  
SK}HXG{?  
2=Jmi?k  
} 7f[8ED[4  
9Y\F53p&j  
aam1tm#Q  
public void run() JTjzT2`A.  
{ 8.PXTOhVL  
//获得文件长度 Z5yt]-WN&  
//分割文件 T4l-sJ'|  
//实例FileSplitterFetch k-io$  
//启动FileSplitterFetch线程 yB|]LYh  
//等待子线程返回 BSjbnnW}"  
try{ 8Er[M  
if(bFirst) 7G?Ia%u  
{ F>TYVxQ  
nFileLength = getFileSize(); $+iu\MuX  
if(nFileLength == -1) zz[g{[SN  
{ gW/QFZjY  
System.err.println("File Length is not known!"); 2Qw )-EB  
} #wGQv  
else if(nFileLength == -2) \l>q Y(gu  
{ %}\ vW  
System.err.println("File is not access!"); ]<Z&=0i#9  
} -aC!0O y`  
else t7sUtmq  
{ DS.39NY  
for(int i=0;i<nStartPos.length;i++) #*[,woNk  
{ 2lX[hFa5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); vI4%d,  
} 9UB??049z  
for(int i=0;i<nEndPos.length-1;i++) 2&suo!ig  
{ {_": / A  
nEndPos = nStartPos[i+1]; <XU8a:w'T  
} h5<T.vV  
nEndPos[nEndPos.length-1] = nFileLength; h 3eGq:!9  
} Xqc'R5C w  
} 0c%@e2(N  
aB/{ %%o  
WNCM|VUl  
//启动子线程 3we.*\2$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jq7vOr-_g  
for(int i=0;i<nStartPos.length;i++) (N&k}CO]W  
{ ^)(G(=-Rf  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u Eu6f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), n$nne6|O  
nStartPos,nEndPos,i); TJeou# =/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H9.oVF^~  
fileSplitterFetch.start(); S(@*3]!q  
} _G_ &Me0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kyp U&F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); fQ2!sV  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", GZxglU,3T  
nEndPos = " + nFileLength); ;a#}fX  
// fileSplitterFetch[nPos.length-1].start(); Sn_z  
wjN`EF5$}&  
u>JqFw1  
//等待子线程结束 6RR4L^(m  
//int count = 0; 4`?sE*P@`  
//是否结束while循环 ~)WfJ  
boolean breakWhile = false; =d:R/Z%,  
 O6M}W_  
=U)n`#6_j2  
while(!bStop) IwZZewb-a  
{ > #Grf)@"6  
write_nPos(); azz#@f1  
Utility.sleep(500); D}=/w+  
breakWhile = true;  |JirBz  
DQL06`pX/  
AAeQ-nbP  
for(int i=0;i<nStartPos.length;i++) Dx p>  
{ }rFsU\]:q  
if(!fileSplitterFetch.bDownOver) w0q?\qEX  
{ KZ367&>b7  
breakWhile = false; I{i:B  
break; yfRUTG  
} (cPeee%Q  
} :)^# xE(  
if(breakWhile) &>+I7Ts]  
break; 6qz!M  
+An![1N,  
O2V6UX@&<w  
//count++; EF*oPn0|  
//if(count>4) w>/pQ6=OFR  
// siteStop(); Ww a41z  
} t?3{s\z8+  
muqfSF  
]4LT#  
System.err.println("文件下载结束!"); Yc. ~qmG/z  
} \N'hbT=  
catch(Exception e){e.printStackTrace ();} R{2GQB  
} "-~D! {rS  
5~<a>>  
%l9WZ*yZ`2  
//获得文件长度 X r  
public long getFileSize() Z L6~Eut  
{ 5JXzfc9rL  
int nFileLength = -1; u"Hd55"&  
try{ / y":/" h  
URL url = new URL(siteInfoBean.getSSiteURL()); ]$XBd{\D{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T_YMM'`  
httpConnection.setRequestProperty("User-Agent","NetFox"); '6d D^0dZ  
xv(xweV+d  
q;Ar&VrlNq  
int responseCode=httpConnection.getResponseCode(); '.}6]l  
if(responseCode>=400) yNb#Ia  
{ utFcFd X  
processErrorCode(responseCode); {Q#Fen ;y|  
return -2; //-2 represent access is error iuH8g  
} 32)&;  
\$$b",2 h  
F$sF 'cw  
String sHeader; Nd]%ati?  
Qzs\|KS  
vV&AG1_Mv  
for(int i=1;;i++) h[[/p {z  
{ R~x;X3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); x]mye  
//Utility.log(in.readLine()); -x3tx7%  
sHeader=httpConnection.getHeaderFieldKey(i); "p6:ekw  
if(sHeader!=null) #qiGOpTF.  
{ RT_Pd\(qD  
if(sHeader.equals("Content-Length")) tnKpn-LPA  
{ 0Tn|Q9R  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,h5-rw'  
break; ]C!Y~  
} 8g2-8pa{  
} i\DHIzGp[  
else ]y)R C-N  
break; ]<o.aMdV  
} 7zJh;f/  
} ^V0{Ew /x  
catch(IOException e){e.printStackTrace ();} c5mhl;+'  
catch(Exception e){e.printStackTrace ();} ;'WzfJ!q  
-Uhl9 =  
q!9v}R3(  
Utility.log(nFileLength); U d=gdsL  
3 DO$^JJ.  
4 L~;>]7  
return nFileLength; M#8Ao4 T  
} X~Rk ,d3  
!=q:> }g  
BF1O|Q|d6  
//保存下载信息(文件指针位置) |<+|Du1  
private void write_nPos() #G4~]Qml  
{ -XDP-Trk  
try{ u`H@Q&(^wa  
output = new DataOutputStream(new FileOutputStream(tmpFile)); bTy' 5"  
output.writeInt(nStartPos.length); 3Mh,NQB  
for(int i=0;i<nStartPos.length;i++) /PB3^d>Q2  
{ D=I5[t0c4  
// output.writeLong(nPos); gQ@Pw4bA  
output.writeLong(fileSplitterFetch.nStartPos); 65`'Upu  
output.writeLong(fileSplitterFetch.nEndPos); .KwuhmR  
} ZjI/zqBm  
output.close(); f)s_e  
} {p lmFV  
catch(IOException e){e.printStackTrace ();} e2=,n6N]c  
catch(Exception e){e.printStackTrace ();} -R8!"~o  
} pg& ]F  
w or'=byh\  
fE7a]R EK  
//读取保存的下载信息(文件指针位置) v BeU  
private void read_nPos() R82Zr@_  
{ *O}'2Ht6\  
try{ M]/wei"X  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .V)2Tz  
int nCount = input.readInt(); ??e#E[bI  
nStartPos = new long[nCount]; OTtanJ?  
nEndPos = new long[nCount]; ]JCB^)tM  
for(int i=0;i<nStartPos.length;i++) c7TWAG_+  
{ 5P t}  
nStartPos = input.readLong(); 9{^B Tc  
nEndPos = input.readLong(); :7PSZc:xE  
} XL&eJ  
input.close(); a ~iEps  
} 'N5r2JL[w  
catch(IOException e){e.printStackTrace ();} t=pkYq5t8  
catch(Exception e){e.printStackTrace ();} [m+O0VK$  
} d(B;vL@R2V  
]!Aze^7;  
~JmxW;|_x)  
private void processErrorCode(int nErrorCode) \g6 # MNW  
{ O@(.ei*HJ!  
System.err.println("Error Code : " + nErrorCode); }${ZI  
} &=yqWW?  
eiSO7cGy  
d8q$&(]<  
//停止文件下载 \,IDLXqp  
public void siteStop() HgBEV  
{ yI)fu^  
bStop = true; @j8L{FGnN  
for(int i=0;i<nStartPos.length;i++) &7kSLat+9{  
fileSplitterFetch.splitterStop(); sbiDnRf  
rJ~(Xu>,s  
Fe2 -;o  
} d?qO`- ~$  
} r-"`Abev  
//负责部分文件的抓取 )Jjw}}$}Y  
**FileSplitterFetch.java pS)X\Xyw  
*/ )mZy>45  
package NetFox; 3z. >b  
:V1ZeNw  
l0bT_?LhK  
import java.io.*; cXE y>U|/  
import java.net.*; (L  
DmpJzH j|  
] 8cX#N,M  
public class FileSplitterFetch extends Thread { g$+O<a@n  
c94PWPU  
cFNtY~(b  
String sURL; //File URL NU\t3JaR  
long nStartPos; //File Snippet Start Position (8X8<>w~  
long nEndPos; //File Snippet End Position  KNyD}1  
int nThreadID; //Thread's ID S5 oHe4#89  
boolean bDownOver = false; //Downing is over |;1:$E"  
boolean bStop = false; //Stop identical op{(mn  
FileAccessI fileAccessI = null; //File Access interface 0QSi\: 1f  
{1&,6kJF&9  
a}]@o"  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &aht K}u  
{ lukRFN>c"  
this.sURL = sURL; ~,4Znuin  
this.nStartPos = nStart; =]k_Oq-1h  
this.nEndPos = nEnd; Rl!WH%;c[X  
nThreadID = id; x,*t/nzR  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .4)P=*  
} 2"K~:Tm#w  
!g:G{b  
O6 J<Lqgh  
public void run() (c7{dYV  
{ 8l,hP.  
while(nStartPos < nEndPos && !bStop) [GT1,(}. Z  
{ p2?+[d  
zi 14]FWo  
uUB%I 8  
try{ 8[p6C Jl)  
URL url = new URL(sURL); !8M'ms>s=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'WgwLE_  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,>%r|YSJ)  
String sProperty = "bytes="+nStartPos+"-"; *iN]#)3>  
httpConnection.setRequestProperty("RANGE",sProperty); t/BiZo|zl  
Utility.log(sProperty); I:7,CV  
 -~aEqj#?  
6Z}))*3 9  
InputStream input = httpConnection.getInputStream(); ~PvzUT-^  
//logResponseHead(httpConnection); ]b$,.t5  
.B n2;nO  
EqU[mqeF  
byte[] b = new byte[1024]; $1 \!Oe[i  
int nRead; .F|WQ7Mu  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Hx0,kOh)  
{ R63d `W  
nStartPos += fileAccessI.write(b,0,nRead); Mo=-P2)>lt  
//if(nThreadID == 1) a5S/ O;ry  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B{KD  ]  
} fYPU'"hzG  
2|o$eq3t  
vw 2@}#\:  
Utility.log("Thread " + nThreadID + " is over!"); 6%y: hLT  
bDownOver = true; by[(9+/z$  
//nPos = fileAccessI.write (b,0,nRead); k/Ro74f=  
} wd0ACF  
catch(Exception e){e.printStackTrace ();} WSwmX3rn  
} Vjd =F.V+  
} '.<"jZ  
m$: a|'mS  
~q>ilnL"h  
//打印回应的头信息 ?P]md9$(+e  
public void logResponseHead(HttpURLConnection con) 1mM52q.R4  
{ |B.d7@{mM  
for(int i=1;;i++) q|2C>{8  
{ ,DZLEsFM  
String header=con.getHeaderFieldKey(i); bGa":|}F  
if(header!=null) E6)mBAE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); V lNzm  
Utility.log(header+" : "+con.getHeaderField(header)); u^p[zepW\  
else 03;(v%  
break; /LzNr0>2  
} b)@x@3"O  
} I@+<[n2  
S5!2%-;<k  
%>z}P&Yz  
public void splitterStop() gf>5xf{M  
{ ;zG|llX  
bStop = true; R6Lr]H  
} "j>0A Hem  
\H(,'w7H  
+[DVD  
} gk` .8o  
ugP R)tDfM  
?A>-_B  
/* *k$&Hcr$  
**FileAccess.java U7=Z.*/62  
*//文件访问(定位,写) _Pal)re]U  
package NetFox; y_#wR/E)u{  
import java.io.*; = ByW`  
56dl;Z)  
\O~P !`  
public class FileAccessI implements Serializable{ Q4*cL5j  
G_]mNh  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p(>'4#|qy  
RandomAccessFile oSavedFile; ^j7pF.j  
long nPos; {BU,kjv1g  
D bJ(N h  
35T7g65;  
public FileAccessI() throws IOException EK^2 2vi$  
{ us+adS.l&  
this("",0); X}Fv*  
} V ZGhF!To  
q?\D9aT9  
HC+R :Dz  
public FileAccessI(String sName,long nPos) throws IOException 10 ^=1@U  
{ / [M~##%:  
oSavedFile = new RandomAccessFile(sName,"rw"); Rz]bCiD3 B  
this.nPos = nPos; -9EbU7>!  
oSavedFile.seek(nPos); *<1m 2t>.  
} UHWun I S  
d8po`J#nb  
ZW"J]"A  
public synchronized int write(byte[] b,int nStart,int nLen) NKws;/u  
{ ImVe 71mh  
int n = -1; ^;d;b<  
try{ /_8V+@im  
oSavedFile.write(b,nStart,nLen); G39t'^ZK*#  
n = nLen; v\vn}/>*d  
} 8iRQPV-"_  
catch(IOException e) fkM4u<R^  
{ Tj:F Qnx  
e.printStackTrace (); vvCGzOv  
} JAK*HA  
" B1' K8  
[cq>QMW  
return n; W2^R$"U  
} "cx" d:  
m" Gr pE3  
Y/gCtSF  
} 2S3F]fG0  
B!0[LlF+  
zFI bCv8  
/* (WC<XKf  
**SiteInfoBean.java M-_)CR  
*/ M=%p$\x  
package NetFox; 6._):[_2  
1mqFnVkf&+  
b,wO^07-3^  
public class SiteInfoBean { [B Al  
u CXd% CzE  
:>=,sLfJ  
private String sSiteURL; //Site's URL gTT-7  
private String sFilePath; //Saved File's Path 53A=O gk8S  
private String sFileName; //Saved File's Name (,>`\\  
private int nSplitter; //Count of Splited Downloading File bc-"If Z&  
_" n4SXhq  
|Cm}%sgR\0  
public SiteInfoBean() 4p]Y`];U  
{//nSplitter的缺省值为5 %{Gqhb=u\  
//default value of nSplitter is 5 5"+* c@L  
this("","","",5); a%kj)ah  
} !jm a --  
s*;~CH-[  
UOyP6ej  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) U4g ZW]F  
{ `#hy'S:e  
sSiteURL= sURL; 2mRso.Ah  
sFilePath = sPath; XB?!V|bno  
sFileName = sName; KE_Ze\ P  
this.nSplitter = nSpiltter; pR $c<p  
\hz)oC   
U1Oq"Ij~  
} |kn}iA@72p  
Z(s} #-  
.s+e hZ  
public String getSSiteURL()  Cfi5r|S  
{ u[% #/  
return sSiteURL; j2z$kw%  
} wBf bpoE7  
Tb[GZ,/%;  
*m7e>]-  
public void setSSiteURL(String value) A /MOY@%G  
{ tU(6%zvR  
sSiteURL = value; @U}UCG7+  
} ny}?+&K  
\l`;]cA  
WrV|<%EQh  
public String getSFilePath() )S]c'}^  
{ XH/|jE.9^|  
return sFilePath; tC;D4i  
} |D\ ukml  
,?}TSJKC  
4 P.ry|2  
public void setSFilePath(String value) Sdn] f4  
{ ."2V:;;  
sFilePath = value; .]" o-(gB  
} )}EwEM  
`hbM 2cM  
N7[~Y2i  
public String getSFileName() &CS=*)>$  
{ \"Np'$4eu  
return sFileName; P?I"y,_ p  
} XjV7Ew^7  
- na]P3 s  
Tb}b*d3  
public void setSFileName(String value) ALG +  
{ }"szL=s  
sFileName = value; ,HkJ.6KF  
} i}Y:o}  
_C##U;e!  
, vR4x:W  
public int getNSplitter() }\9qN!ol  
{ Q5Wb)  
return nSplitter; ]UNmhF!W>u  
} 2Bx\nLf/ K  
Q<M>+U;t  
Dd*C?6  
public void setNSplitter(int nCount) x[_+U4-/  
{ Ft07>E$/Q^  
nSplitter = nCount; 0g1uM:;  
} ] `lTkh  
} O)hNHIF  
iM\W"OUl[  
RW3&]l=  
/* s}5;)>3~@  
**Utility.java 0s(G*D2%6  
*/ 8garRB{  
package NetFox; ~;MRQE  
lwV#j}G  
f>Ge Em~  
public class Utility { bk V_ ^8  
^JH 4: h  
rx%lL  
public Utility() AH;h#dT  
{ PJ);d>tz  
V ] Z{0  
gI[x OK#  
} q$\KE4v"  
7r:!HmRl  
//线程睡眠 Zb@PwH4  
public static void sleep(int nSecond) Mq-;sPsFP  
{ -cMqq$  
try{ R@;kY S  
Thread.sleep(nSecond); %/4ChKf!VR  
} 0PZpE "$X  
catch(Exception e) At"@`1n_u'  
{ b8Y-!] F  
e.printStackTrace (); }e1f kjWk  
} h]I ^%7  
} $~_TE\F1  
X'O3)Yg  
//日志 Wq]^1g_  
public static void log(String sMsg) M4`qi3I  
{ -_B*~M/vV`  
System.err.println(sMsg); &kh-2#E  
} 3~Ah8,  
[V =O$X_  
p?ICZg:  
public static void log(int sMsg) xse8fGs  
{ 8^kw  
System.err.println(sMsg); dtJ?J<m}  
} {"-uaH>,  
} 3b~k)t4R  
X"*pt5B6`  
$)6y:t"  
/* I_\j05  
**TestMethod.java ih~ R?W  
*/ !?,rcgi  
package NetFox; 2Lm.;l4YO  
ca5Ir<mL  
NU O9,  
public class TestMethod { /alJN`g  
i ,ga2{GnM  
Ub3^Js!b%  
public TestMethod() I vO#tI  
{ ///xx/weblogic60b2_win.exe <8~bb- U$  
try{ M/T ll]\|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )ui]vS:>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); eqV;4dhm  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Y$ ZZ0m  
fileFetch.start(); 4~4D1  
} bs/Vn'CE  
catch(Exception e){e.printStackTrace ();} (/JiOg^cw  
uS;N&6;:  
M $ CnaH  
} F@UbUm2o  
jhg0H2C8  
wX[g\,?}'  
public static void main(String[] args) IBZ_xU\2  
{ ,:;ZzHzR0  
new TestMethod(); ?`8jn$W^  
} f<?v.5($  
} E0G"B' x  
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