http断点续传简单实现（java)

/* bjPI:j*XU  
**SiteFileFetch.java !40{1U&@a`  
*/ 3nd02:GF  
package NetFox; {"y{V  
import java.io.*; f'Wc_L)  
import java.net.*; \%&QIe;:k  
$rs7D}VNc  
z1f~:AdL  
public class SiteFileFetch extends Thread { 9NaC7D$,  
|k)h' ?  
v;el= D  
SiteInfoBean siteInfoBean = null; //文件信息Bean ")ow,r^"  
long[] nStartPos; //开始位置 x*i5g`jx  
long[] nEndPos; //结束位置 Y1{6lhxgE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8l>/ZZ.NXi  
long nFileLength; //文件长度 #g4X`AHB  
boolean bFirst = true; //是否第一次取文件 ma~WJ0LM\  
boolean bStop = false; //停止标志 dSsMa3X[n  
File tmpFile; //文件下载的临时信息 g-oHu8  
DataOutputStream output; //输出到文件的输出流 Vj0`*nC)/  
qOZe\<.V<  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -:pLlN-f  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5LhFD  
{ PQ@(p%
 
siteInfoBean = bean; U;OJ.a9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8iK>bp  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `iv,aQ '  
if(tmpFile.exists ()) ],>Z'W  
{ oQ8W0`bZa  
bFirst = false; RFDwL~-p  
read_nPos(); ~8`r.1aUO  
} Rla1,{1  
else b,D+1'  
{
h:"<x$F  
nStartPos = new long[bean.getNSplitter()]; 5Tb93Q@c  
nEndPos = new long[bean.getNSplitter()]; B Gh%3"q  
} #`);UAf  
"1&C\}.7  
1A< O Z>  
`DC)U1  
} (Pin9^`ALc  
rh${pHl  
d;:+Xd`  
public void run() 0#G&8*FMN  
{ ~${.sD\  
//获得文件长度 &0K H00l  
//分割文件 a)Qx43mOS  
//实例FileSplitterFetch ;wp)E nF  
//启动FileSplitterFetch线程 @/`b:sv&*  
//等待子线程返回 d.% Vm&3  
try{ #";(&|7  
if(bFirst) cDxjD5E  
{ :I+%v  
nFileLength = getFileSize(); G7M:LcX  
if(nFileLength == -1) IM}#k$vM:  
{ .?[2,4F;  
System.err.println("File Length is not known!"); hR[Qdu6r  
} kJlRdt2  
else if(nFileLength == -2) ]. IUQ*4t  
{ C*/d%eHD  
System.err.println("File is not access!"); H^B/ '#mO  
} ,N<xyx.  
else Pp@P]  
{ +g/y)]AP  
for(int i=0;i<nStartPos.length;i++) `Q,moz  
{ 55zimv&DV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |TkMrj0  
} #QXB2x<*  
for(int i=0;i<nEndPos.length-1;i++) g&\A1H  
{ <lB^>Hfu  
nEndPos = nStartPos[i+1]; v5;c}n  
} wX<)Fj'  
nEndPos[nEndPos.length-1] = nFileLength; QApil  
} w6qx  
} ql2>C.k3L  
k,0JW=Vh>|  
wg<DV!GZ  
//启动子线程 ]Yp;8#:1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; H8mmmt6g  
for(int i=0;i<nStartPos.length;i++) z$QYl*F1  
{ ,~hvF
TJI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y7u"a)T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >IJH#>i  
nStartPos,nEndPos,i); ("}
TW-r~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V[(zRGa{  
fileSplitterFetch.start(); ';^VdR]fk  
} 7Fh%jRHZ`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xeIt7b?#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X<OwB-N  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^}a..@|%W  
nEndPos = " + nFileLength); (ye1t96  
// fileSplitterFetch[nPos.length-1].start(); Y#=0C*FS  
sPyq.oG  
& VJ+X|Z  
//等待子线程结束 7s4G|N[wR\  
//int count = 0;
?R(fxx  
//是否结束while循环 *_}ft-*w  
boolean breakWhile = false; U,gg@!1GJo  
nVoL7ew+  
z{wJQZ9"  
while(!bStop) i/6(~v  
{ _s[ohMlh  
write_nPos(); \'xF\V  
Utility.sleep(500); @!=q.
4b  
breakWhile = true; yTm/P!1S  
]o$aGrZ  
%c<e`P;  
for(int i=0;i<nStartPos.length;i++) ^RAst1q7  
{ <'>c`80@\*  
if(!fileSplitterFetch.bDownOver) v,I4ozDx  
{ 1Mn=m w  
breakWhile = false; DI{VJ&n66  
break; i+ ]3J/J  
} *39Y1+=)$$  
} 3
+%a  
if(breakWhile) x"9`w42\r  
break; tBd-?+~7  
i%_W{;e  
pZ,=iqr  
//count++; Hz) Xn\x  
//if(count>4) J: vq)G\F  
// siteStop(); (u-K^xC  
} w[YiH $  
0ft81RK  
]$oo1ssZ1  
System.err.println("文件下载结束！"); 3k(A&]~v  
} 3q:U0&F  
catch(Exception e){e.printStackTrace ();} *'H0%GM  
} &b'IYoe  
R}_B\#Q  
 Sg  
//获得文件长度 rE$0a-d2B  
public long getFileSize() RL4J{4
K  
{ {e~#6.$:  
int nFileLength = -1; $REz{xgA=  
try{ i/E"E7  
URL url = new URL(siteInfoBean.getSSiteURL()); Y)H~*-vGu  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &OQ37(<_  
httpConnection.setRequestProperty("User-Agent","NetFox"); _JNSl2  
s;e%*4  
td JA?  
int responseCode=httpConnection.getResponseCode(); `k2YH?  
if(responseCode>=400) f8E,.$>  
{ "A\h+q-  
processErrorCode(responseCode); @( p
9}  
return -2; //-2 represent access is error K~Nx;{{d  
} L|ZxB7xk  
C$WUg<kcK'  
*lyy|3z  
String sHeader; e0;0X7  
Vl'Gi44)3"  
xs,,)jF(u  
for(int i=1;;i++) g]&7c:/  
{ IJ\4S  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); iOY: a  
//Utility.log(in.readLine()); o|`[X'  
sHeader=httpConnection.getHeaderFieldKey(i); $0 ]xeD0X  
if(sHeader!=null) ;$,b w5  
{ L7\V^f%yCm  
if(sHeader.equals("Content-Length")) F3nYMf  
{ RK)1@Tz7!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3fGL(5|_  
break; M`V<`  
} M/?eDW/  
} t
E'^O< K  
else R*0]*\C z  
break; jRiXN%  
} p{|!LcSU$2  
} ]QC9y:3  
catch(IOException e){e.printStackTrace ();} .>#X*u  
catch(Exception e){e.printStackTrace ();} >PuQ{T I  
%\"<lyD
 
MHj RPh  
Utility.log(nFileLength); FD'yT8]"  
@cB7tY*Ski  
HTz5LAe~b7  
return nFileLength; hk+8s\%-  
} H#Hhi<2  
wxJu=#!M  
[[$dPa9  
//保存下载信息（文件指针位置） ,>!%KYD/f  
private void write_nPos() .jUM'; l  
{ fHK.q({Qc  
try{ 9U>OeTh(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2OVN9_D%  
output.writeInt(nStartPos.length); ]
*?lgwE  
for(int i=0;i<nStartPos.length;i++) @yM
$Et5  
{ w**~k]In  
// output.writeLong(nPos); CY~ S{w  
output.writeLong(fileSplitterFetch.nStartPos); 60TM!\  
output.writeLong(fileSplitterFetch.nEndPos); R1$s1@3I|  
} s Poh\n  
output.close(); \&_pI2X  
} kx?f,^-  
catch(IOException e){e.printStackTrace ();} BItH0r7  
catch(Exception e){e.printStackTrace ();} 7Q^p|;~a  
} iD*21c<kd  
40%fOu,u`  
p$=Z0p4%LL  
//读取保存的下载信息（文件指针位置） NX4G;+6  
private void read_nPos() fUMjLA|*I<  
{ !\VzX  
try{ e@Mg9VwDc  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); w_h{6Kc<  
int nCount = input.readInt(); B"YN+S
o  
nStartPos = new long[nCount]; 5^D094J|^  
nEndPos = new long[nCount]; "1$
X5?%  
for(int i=0;i<nStartPos.length;i++) h0R.c|g[  
{ D V\7KKJE  
nStartPos = input.readLong(); $Qz<:?D  
nEndPos = input.readLong(); 7Kf  
} {]bmecz  
input.close(); N5c*#lHI  
} L;lu)|b"  
catch(IOException e){e.printStackTrace ();} E{0e5.{  
catch(Exception e){e.printStackTrace ();} Mz.C`Z>o  
} #{*5rKiL  
v
w 6$v  
yAAV,?:o[  
private void processErrorCode(int nErrorCode) 3[j,d]\|  
{ jzJQ/ZFS  
System.err.println("Error Code : " + nErrorCode);  svx7  
} AyWdJ<OU  
eR4ib-nS  
JH| D  
//停止文件下载 No"i6R+  
public void siteStop() e^em^1H( %  
{ el U%Z9  
bStop = true; ?N<,;~  
for(int i=0;i<nStartPos.length;i++) O|S,="h"}  
fileSplitterFetch.splitterStop(); ,,H;2xYf  
_CPj]m{  
ber
&!9  
} 118l
b]  
} pV(k6h  
//负责部分文件的抓取 1d~d1Rd  
**FileSplitterFetch.java ]isq}Qv~  
*/ s>:gL,%c  
package NetFox; e/cHH34  
V@]SKbK}wN  
[ :)
F-  
import java.io.*; 8!0fT}  
import java.net.*; Zr1"'+-  
sBYDo{01  
YO-B|f  
public class FileSplitterFetch extends Thread { H#7=s{u  
qSlo)aP  
VH4wsEH]  
String sURL; //File URL t #Kucde  
long nStartPos; //File Snippet Start Position $3B%4#s  
long nEndPos; //File Snippet End Position g%tUkM  
int nThreadID; //Thread's ID `*[\b9>  
boolean bDownOver = false; //Downing is over t{yj`Vg  
boolean bStop = false; //Stop identical 1X2|jj  
FileAccessI fileAccessI = null; //File Access interface gaQ E'qp>  
G6
2;p#  
~"0{<mMcX  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException x&^Xgi?  
{ \9@}0}%`  
this.sURL = sURL; 1) K<x  
this.nStartPos = nStart; [u;(4sa}  
this.nEndPos = nEnd; sxA]o|  
nThreadID = id; <{8x-zbR+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pY-!NoES  
} 9od c :  
WMnSkO  
dl[%C6  
public void run() u$[&'D6  
{ 0LXu!iix  
while(nStartPos < nEndPos && !bStop) s0]ZE\`H>  
{ ?]bx]Y;
 
;hODzfNkS  
k>Fw2!mA^  
try{ WV'u}-v^  
URL url = new URL(sURL); f+ZOE?"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *;McX  
httpConnection.setRequestProperty("User-Agent","NetFox"); g]JRAM  
String sProperty = "bytes="+nStartPos+"-"; ^wc:qll  
httpConnection.setRequestProperty("RANGE",sProperty); shL_{}  
Utility.log(sProperty); ~8UMw
pl-  
@YRy)+  
`n-/~7  
InputStream input = httpConnection.getInputStream(); d&L  
//logResponseHead(httpConnection); =w;-4  
J @~g>  
uPbdzUk$  
byte[] b = new byte[1024]; cUP1Uolvn  
int nRead; y${`W94  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Mv/ SU">F  
{ : O@(Sv  
nStartPos += fileAccessI.write(b,0,nRead); rN7JJHV  
//if(nThreadID == 1) "M+I$*]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =O"l/\c^  
} tS\Db'C7  
qhG2j;  
_a9oHg  
Utility.log("Thread " + nThreadID + " is over!"); vol (%wB  
bDownOver = true; jj;TS%  
//nPos = fileAccessI.write (b,0,nRead); As5
l36  
} 0FH.=   
catch(Exception e){e.printStackTrace ();} %Jd!x{a`>A  
} gBWr)R  
} /qwY/^  
<Piq?&VX[  
E}F-*go  
//打印回应的头信息 6vTnm4  
public void logResponseHead(HttpURLConnection con) *kZH~]  
{ k^ fW/  
for(int i=1;;i++) ~*\ *8U@7  
{ X{i>Q_8>  
String header=con.getHeaderFieldKey(i); |{-?OOKj  
if(header!=null) -OmpUv-O"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !B#lZjW#  
Utility.log(header+" : "+con.getHeaderField(header)); @c"s6h&  
else C2zKt/)A  
break; d:vc)]M>f{  
} 90Sras>F  
} Uc,

..  
t>LSP$  
<C;TGA  
public void splitterStop() Y`$\o  
{ Unq~lt%2  
bStop = true; g] ]6)nT  
} %qE"A6j  
&Qj1uf92.  
3m4 sh~  
} snu?+*6  
Ay^P#\VZ  
"Y5 :{Kj  
/* JV4fL~  
**FileAccess.java i|,}y`C#  
*//文件访问(定位，写) U7g,@/Qx  
package NetFox; L:?Ew9Lf  
import java.io.*; eTw9c }[  
S9nn^vsK  
y0?HZ Xq  
public class FileAccessI implements Serializable{ 0"TPY(n  
iPG:w+G  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *wd=&Z^19  
RandomAccessFile oSavedFile; +R;LHRS%  
long nPos; [ybK  
umAO&S.+M  
j` * bz-  
public FileAccessI() throws IOException R-,L"Vv  
{ f w)tWJVD  
this("",0); 9jx>&MnWs  
} 3fZoF`<a  
pEN`6*  
U,fPG/9  
public FileAccessI(String sName,long nPos) throws IOException pzQc UG  
{ H,GnF  
oSavedFile = new RandomAccessFile(sName,"rw"); aM#xy6:XG  
this.nPos = nPos; mF4OLG3L0  
oSavedFile.seek(nPos); <pKOFN%
m  
} b KDD29  
cG@Wo8+  
ux6)K= ]  
public synchronized int write(byte[] b,int nStart,int nLen) RF -c`C  
{ z^4+Un  
int n = -1; 1~2+w]-kU  
try{ $rbr&TJ  
oSavedFile.write(b,nStart,nLen);  z.2UZ%:  
n = nLen; 4@mJEi{  
} )Wt&*WMFXl  
catch(IOException e) u%1JdEWZd  
{ yiH;fK+x  
e.printStackTrace (); ;yjw(OAI*  
} 4&e<Sc64  
M\JAB ;A  
Y-+Kf5_[  
return n; b`DPlQHj  
} $ER$|9)KD  
a?Y>hvI  
If'N0^'W  
} WHLTJ]OB  
e~,+rM  
V;)+v#4{  
/* ]ERAt^$0  
**SiteInfoBean.java pRsIi_~&  
*/ tF<&R&=  
package NetFox; ~rXLb:  
mT|r:Yr:  
?LvU7  
public class SiteInfoBean { jSdC1,wR  
AxO.adQE%  
m?4HVv  
private String sSiteURL; //Site's URL 'b>3:&  
private String sFilePath; //Saved File's Path X%;4G^%ZI  
private String sFileName; //Saved File's Name vYo~36  
private int nSplitter; //Count of Splited Downloading File w=ufJRj  
0dD.xuor  
S~|\bnE  
public SiteInfoBean() q 4Ok$~"I  
{//nSplitter的缺省值为5 <5h}\5#<j  
//default value of nSplitter is 5 c@j3L23B  
this("","","",5); !# xi^I  
} /P/0\3TCi  
{8%KO1xB  
0/%RrE  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "N}MhcdS  
{ Gsm.a  
sSiteURL= sURL; 6]HMhv  
sFilePath = sPath; "0z4mQ}>N  
sFileName = sName; XN3'k[  
this.nSplitter = nSpiltter; <0Gk:NB,  
-xyY6bxL  
ybIqn0&[  
} iUqD>OV  
Fd%JF#
Hk  
rTST_$"_6  
public String getSSiteURL() %h
z5)  
{ Y%(8'Ch  
return sSiteURL; Q5 o0!w  
} usi3z9P>n  
#nj;F'O](  
mMCd  
public void setSSiteURL(String value) ScT{Tb]9bt  
{ PHH,vO[eO  
sSiteURL = value; N6*FlG-  
} 5+(Cp3
  
Tj6Czq=*%T  
ZF<$6"4N  
public String getSFilePath() tq*6]q8c>  
{ UdpuQzV<4`  
return sFilePath; T*(mi{[T  
} ;j<#VS-]  
q[. p(6:  
 -f<}lhmQ  
public void setSFilePath(String value) =C7<I   
{ "837b/>/  
sFilePath = value; scE#&OWF%  
} ? a/\5`gnN  
[BEQ ~A_I  
^i@0P}K<  
public String getSFileName() eK\i={va  
{ uj)f
ah?Wg  
return sFileName; x-q_sZ^8  
} +7y#c20  
5ne&6  
?MSV3uODb  
public void setSFileName(String value) ' Yy+^iCus  
{ 9!dG Xq  
sFileName = value; bq}`jP~#  
} 'XOWSx;Y  
"_+8z_  
E$v!Z;A  
public int getNSplitter() d-H03F@N  
{ >YcaFnY  
return nSplitter; ahN8IV=+Gm  
} X'/'r
.b6  
4S* X=1  
8 9maN  
public void setNSplitter(int nCount) ]r\!Z <<(  
{ 3/,}&SX  
nSplitter = nCount; yQN^F+.  
} 'sa>G  
} T#&X7!4  
Bf3 QB]9  
nIfp0U*  
/* n8z++T&  
**Utility.java S>s+ nqcP  
*/ 79+i4(H  
package NetFox; fY|[YPGO^  
sH%Ts@Pl  
MG^YT%f  
public class Utility { 8\+DSA  
E<@N4%K_Q  
]\/"-Y#4Q  
public Utility() xO4""/
n  
{ xiqeKoAD  
"z-tL  
MieO1l  
} m;ju@5X  
-U|Z9sia  
//线程睡眠 bicbCC6kC  
public static void sleep(int nSecond) i*T -9IP  
{ bR?xz-g%<3  
try{ ~G.MaSm  
Thread.sleep(nSecond); #9{2aRCJ  
} yqP=6   
catch(Exception e) O.{
  
{ CXTtN9N9  
e.printStackTrace (); $h5QLN   
} t~":'le`zr  
} ``>z8t[ks  
Z tc\4  
//日志 Z1]4:  
public static void log(String sMsg) uXb}oUC  
{ ^4et; F%  
System.err.println(sMsg); q(v|@l|)yO  
} v<mSd2B*  
d?V/V'T[  
wn\R|'Rdz  
public static void log(int sMsg) E H|L1g  
{ Q /t_%vb  
System.err.println(sMsg); #+$PD`j  
} Q`Rn,kCVy  
} "6v_<t`q"  
,R=$qi|  
_9?v?mL5;  
/* }'Ph^ %ox  
**TestMethod.java K>n@8<7  
*/ bH!_0+$P  
package NetFox; >;%LW} %  
!>/J]/4>  
xc7Rrh]}  
public class TestMethod { s+E4AG1r  
PH'n`
D
#  
a%?v/Ku  
public TestMethod() kYR^  
{ ///xx/weblogic60b2_win.exe Xe(]4Ux  
try{ c{qTVi5e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -#R63f&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O'QnfpQ*9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }g:'K  
fileFetch.start(); Mhc5<~?  
} 'ITZz n*  
catch(Exception e){e.printStackTrace ();} 5xU}}[|~-  
_Ih"*~ r/&  
Q5_,`r`  
} HrT@Df  
Pon0(:#1  
12Fnv/[n'K  
public static void main(String[] args) ^==Tv+T9U  
{ 77j"zr7v  
new TestMethod(); Y@qugQM>  
} 7Q,<h8N\5  
} n8D'fvY  
点击下载更多相关资料