http断点续传简单实现（java)

/* )iQ^HZ  
**SiteFileFetch.java )Wr_*>xj  
*/ !Yv_V]u=  
package NetFox; UaF~[toX  
import java.io.*; }`g-eF>p  
import java.net.*; mXOI"B9Sq  
>Vjn]V5y  
!@F {FR  
public class SiteFileFetch extends Thread { dN)8r  
T7.Iqw3p  
@$ Zh^+x!  
SiteInfoBean siteInfoBean = null; //文件信息Bean Z17b=xJw  
long[] nStartPos; //开始位置 BZ1wE1t  
long[] nEndPos; //结束位置 Y~85Z0l  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 nOvR, 6  
long nFileLength; //文件长度 
_ERtL5^  
boolean bFirst = true; //是否第一次取文件 G<n75!  
boolean bStop = false; //停止标志 M|mfkIk0MB  
File tmpFile; //文件下载的临时信息 ]}XDDPbZ}  
DataOutputStream output; //输出到文件的输出流 $Gv@lZ@=  
>kK@tJn  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ZBK0`7#&EH  
public SiteFileFetch(SiteInfoBean bean) throws IOException "TZY)\{L  
{ "!V`_ S;  
siteInfoBean = bean; ]s AuL
!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Z%]K,9K
 
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); G?'^"ae"Z  
if(tmpFile.exists ()) r|u[36NmA  
{ zR?R,k)m  
bFirst = false; _ZK^JS  
read_nPos(); N*}soMPV^.  
} JM|HnyI  
else jJ$B^Y"4  
{ dX cbS<  
nStartPos = new long[bean.getNSplitter()]; QQ.?A(U7  
nEndPos = new long[bean.getNSplitter()]; \+%~7Bi]z  
} J W@6m  
Wvf>5g)?  
KtL?,zi  
E6TeZ%g  
} Ne1Oz}  
0BlEt1e2T  
/)sP,
2/  
public void run() .EL3}6"A  
{ ,s#~00C|  
//获得文件长度 E5n7 <
 
//分割文件 vS>'LX  
//实例FileSplitterFetch >X$JeME3  
//启动FileSplitterFetch线程 Vb`Vp(>AU  
//等待子线程返回 E=ijt3  
try{ J&>@>47  
if(bFirst) 6+IhI?lI=  
{ I]v2-rB&-  
nFileLength = getFileSize(); P);s0Y|@H  
if(nFileLength == -1) DJ,LQj  
{ [g/D<g5O  
System.err.println("File Length is not known!"); z_$c_J  
} g2|Myz)  
else if(nFileLength == -2) _M%S  
{ ~
4{q  
System.err.println("File is not access!"); iAu/t  
} Y7}Tuy dC  
else Z)`)9]*  
{ Kq3c Kp4  
for(int i=0;i<nStartPos.length;i++) \dtiv&x  
{ I/Vw2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); t^~vi'bB  
}  @./h$]6  
for(int i=0;i<nEndPos.length-1;i++) eUA]OF@  
{ >o?v[:u*  
nEndPos = nStartPos[i+1]; "#r)NYq`"|  
} u;_h%z5K  
nEndPos[nEndPos.length-1] = nFileLength; 7EE{*}?0E  
} fZo#
:"{/K  
} .C% 28fH  
)y,^M3$?C  
mQ:{>`  
//启动子线程 q
,,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;|5-{+2U%  
for(int i=0;i<nStartPos.length;i++) $9,&BW_*  
{ p0@^1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GEWjQ;g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), v745FIy<  
nStartPos,nEndPos,i); )@N d3Z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ZZT #V%Q=u  
fileSplitterFetch.start(); ,0W^"f.g{m  
} ^HC6v;K  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6eV#x%z@v'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); p@Y=6Bw  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",
'E_~|C  
nEndPos = " + nFileLength); ':vZ&  
// fileSplitterFetch[nPos.length-1].start(); eO!9;dJ  
1#A$&'&\J;  
CQ!pt@|d  
//等待子线程结束 3PNdc}h&#  
//int count = 0; ' P?h?w^T  
//是否结束while循环 y@3p5o9lv-  
boolean breakWhile = false; t%lat./yT  
H$h#n~W~  
j<p.#jkT  
while(!bStop) l^lb ^"o  
{ M|*YeVs9#  
write_nPos(); pZnp!!G  
Utility.sleep(500); D<SC
`  
breakWhile = true; ;o9h|LRs  
MUrPr  
h@Q^&%w  
for(int i=0;i<nStartPos.length;i++) wh8';LZ>R  
{ S[Du >  
if(!fileSplitterFetch.bDownOver) j7~FR{:j  
{ *jlIV$r_  
breakWhile = false; U] LDi8  
break; 5'} V`?S  
} ^e.-Ji  
} pE5v~~9Ikv  
if(breakWhile) HuevDy4  
break; `L'g<VK;  
d
vB=Zk]m  
 /|0-O''  
//count++; \R#SoOd  
//if(count>4) )'djqpM.  
// siteStop(); 6X \g7bg  
} W;vNmg}mn  
tk"+ u_uw  
nuce(R  
System.err.println("文件下载结束！"); Fv$tl)p*  
} gQn%RPMh  
catch(Exception e){e.printStackTrace ();} N''QQBUD  
} yKc-:IBb{u  
w' 7sh5  
c7e,lgG-  
//获得文件长度 @Vm*b@  
public long getFileSize() AFrJzh:V[  
{ 9bM\ (s/  
int nFileLength = -1; 80=0S^gEZ  
try{ j6m;0
3<|  
URL url = new URL(siteInfoBean.getSSiteURL()); K zWo}tT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &`r/+B_W  
httpConnection.setRequestProperty("User-Agent","NetFox"); uz8LF47@:-  
U2 *ORd  
U+Y(:  
int responseCode=httpConnection.getResponseCode();
~aob@(  
if(responseCode>=400) $YSXE :  
{ jeC=s~  
processErrorCode(responseCode); #{cy(&cz  
return -2; //-2 represent access is error @aIgif+v  
} 5'zXCHt  
}Le]qR9Y]  
HlGSt$woX  
String sHeader; +,76|oMsQ%  
or]v]*:~l  
7UfNz60+~  
for(int i=1;;i++) 4>KF`?%4  
{ /(dP)ysc  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |mEWN/@C  
//Utility.log(in.readLine()); ,Bk5(e  
sHeader=httpConnection.getHeaderFieldKey(i); ./YR8#,  
if(sHeader!=null) }HgG<.H>  
{ @>2pY_  
if(sHeader.equals("Content-Length")) cQU/z"?+  
{ EeuYRyK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kKX' Y+  
break; 6nx\|F  
} zHJCXTM  
} s)^/3a  
else aO'#!k*R  
break; )^j_O^T5  
} N^L@MR-  
} 8x{Owj:Q  
catch(IOException e){e.printStackTrace ();} s0SzO,Vi  
catch(Exception e){e.printStackTrace ();} 4#$#x=:  
? #K|l*  
mWp>E`l  
Utility.log(nFileLength); zggnDkC5  
.U1wVIM  
P'W} ]mCD  
return nFileLength; g)X3:=['  
} /fI}QY1  
8Y($ F2  
M(-)\~9T  
//保存下载信息（文件指针位置） Ca2r<|uA  
private void write_nPos() LPvp (1  
{ UC!mp?   
try{ tB_le>rhl  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ai!u+L  
output.writeInt(nStartPos.length); }icCp)b>v  
for(int i=0;i<nStartPos.length;i++) '/d
51  
{ *;<fh,wOk  
// output.writeLong(nPos); KWJVc `  
output.writeLong(fileSplitterFetch.nStartPos); WTSh#L  
output.writeLong(fileSplitterFetch.nEndPos); >xFvfuy
C  
} 1NZ"\9=U  
output.close(); LF dvz0  
} L:i&OCU2k  
catch(IOException e){e.printStackTrace ();} ? wS}'  
catch(Exception e){e.printStackTrace ();} :j\7</uu  
} &jqaW2  
gQnr.  
3jx%]S^z|  
//读取保存的下载信息（文件指针位置） pKSCC"i&j  
private void read_nPos() u?^V4 +V  
{ `ecseBn3d  
try{ ({uW-%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @v-
^j  
int nCount = input.readInt(); }[p{%:tP  
nStartPos = new long[nCount]; iJs~NLCgVu  
nEndPos = new long[nCount]; {:X'9NEE  
for(int i=0;i<nStartPos.length;i++) vX+oZj   
{ ^FVdA1~/  
nStartPos = input.readLong(); i)i>Ulj*i  
nEndPos = input.readLong(); opcanl9pSW  
} Hm-#Mpw  
input.close(); '/\  
} `+H=3`}
X  
catch(IOException e){e.printStackTrace ();} }lZEdF9GhG  
catch(Exception e){e.printStackTrace ();} GBJLB  
} |XyX%5p*  
QPlU+5Cx  
X4;U4pU#  
private void processErrorCode(int nErrorCode) `4"8@>D  
{ ]S2rqKB  
System.err.println("Error Code : " + nErrorCode); )2f#@0SVL  
} M8},RR@{  
)GP;KUVae  
\/ bd  
//停止文件下载 J Enjc/  
public void siteStop() %cF`x_h[j  
{ ~D52b1f  
bStop = true; P\U<,f  
for(int i=0;i<nStartPos.length;i++) d4Uw+3ikW  
fileSplitterFetch.splitterStop(); OSu&vFKz  
rj4@  
<8r"QJY/  
} !=9x=  
} s
o-5%S  
//负责部分文件的抓取 'Ru(`" 1|  
**FileSplitterFetch.java qCs/sW  
*/ ghQ B  
package NetFox; ?t/qaUXN  
.:S/x{~  
fc#9e9R  
import java.io.*; {lI}a8DP  
import java.net.*; U:7h>Z0W  
+){^HC\7h  
zJDHDr  
public class FileSplitterFetch extends Thread { LU3pCM{  
h&"9v~  
vs@d)$N  
String sURL; //File URL ETDWG_H |  
long nStartPos; //File Snippet Start Position fNNl1Vls  
long nEndPos; //File Snippet End Position 6H#:rM  
int nThreadID; //Thread's ID wE .H:q4&  
boolean bDownOver = false; //Downing is over Ev fvU:z  
boolean bStop = false; //Stop identical HE}0_x.  
FileAccessI fileAccessI = null; //File Access interface mxlh\'b  
Xaz "!  
zIa={tU  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException x'|ty[87  
{ }k-V(  
this.sURL = sURL; axQ>~vWN/  
this.nStartPos = nStart; (KQLh,h7  
this.nEndPos = nEnd; bT:u|/I  
nThreadID = id; >8Oa(9n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @c~Z0+Ji  
} >X~B1D,SV7  
tP'v;$)9F  
yR$_ZXsd  
public void run() \/Y(m4<P
 
{ Nd(,oXa~  
while(nStartPos < nEndPos && !bStop) !HTOE@  
{ O8;/oL4 U  
9o@3$  
i?T-6
{3I  
try{ Q 3WD!Z8y  
URL url = new URL(sURL); +d, ~h_7!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ieyK$q  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^t0!Dbx3SE  
String sProperty = "bytes="+nStartPos+"-"; k1
Y\g'1  
httpConnection.setRequestProperty("RANGE",sProperty); M;A_'h?Z  
Utility.log(sProperty); 9<mMU:  
Wn<?_}sa|z  
l*ltS(?  
InputStream input = httpConnection.getInputStream(); ,TBOEu."4  
//logResponseHead(httpConnection); _c>iux;  
((M,6Q}  
b(K"CL\p  
byte[] b = new byte[1024]; A
mZXUb  
int nRead; !W}sOK7#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &h:4TaD  
{ Bii'^^I;?  
nStartPos += fileAccessI.write(b,0,nRead); !vz'zy)7  
//if(nThreadID == 1) EjP;P}_iK  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6,t6~Uo/  
} m?S;sew@5  
rm-d),Zt  
V]zZb-m=  
Utility.log("Thread " + nThreadID + " is over!"); XYU5.  
bDownOver = true; OZ`cE5"i  
//nPos = fileAccessI.write (b,0,nRead); E%w^q9C  
} XoN~d  
catch(Exception e){e.printStackTrace ();} ZU 3Psj  
} &8IBf8  
} ^J^,@Hf_  
Sca"LaW1  
7Kw'Y8  
//打印回应的头信息 4[lFurH  
public void logResponseHead(HttpURLConnection con) !2t7s96  
{ ~,lt^@a  
for(int i=1;;i++) ')jItje|  
{ '
|H+5#  
String header=con.getHeaderFieldKey(i); h&4s%:_4  
if(header!=null) fe\lSGmf  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :9&c%~7B9  
Utility.log(header+" : "+con.getHeaderField(header)); *fN+wiPD  
else # ~<]z  
break; 93*csO?Db  
} p%I)&- 8  
} N[Z`tk?-  
&d6@SQ  
eo+<@83  
public void splitterStop() f-~Y  
{ ~[CFs'`(2  
bStop = true; ;L-=z]IR,  
} 7|}4UXr7y  
P@N+jS`Vf  
 /
 
} <+QdBp'd;
 
GDLw_usV  
xvl$,\iqE  
/* v,")XPY  
**FileAccess.java ~b_DFj  
*//文件访问(定位，写) UytMnJ88  
package NetFox; :FAPH8]  
import java.io.*; ,z&S;
f.f  
<rzP  
qvn.uujYS  
public class FileAccessI implements Serializable{ xQ
sxc  
;!<}oZp{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 DI\=udN  
RandomAccessFile oSavedFile; 5dj" UxH  
long nPos; ]\*^G@HA2  
3d}v?q78  
 7)2K6<q  
public FileAccessI() throws IOException F`g(vD>  
{ H07\z1?.K  
this("",0); #eW T-m  
} `n&
:\Ib  
*OLqr/
yb  
1Q@]b_"Xh  
public FileAccessI(String sName,long nPos) throws IOException .UPh  
{ `7/(sX.  
oSavedFile = new RandomAccessFile(sName,"rw"); /1OCK=  
this.nPos = nPos; c~<;}ve^z  
oSavedFile.seek(nPos); J&8KIOz14Z  
} -,8LL@_  
+a5F:3$  
O`Tz^Q/D  
public synchronized int write(byte[] b,int nStart,int nLen) a=2.Y?  
{ Vk{
;g  
int n = -1; \_Bj"K  
try{ P j   
oSavedFile.write(b,nStart,nLen); C|ZPnm>f30  
n = nLen; G)amng/  
}  sS-dHa  
catch(IOException e) "BQnP9  
{ nCYkUDnZ  
e.printStackTrace ();
Ty g>Xv  
} <YvXyIs  
E+]}KX:  
zud_BOq{f  
return n; Im;%.J  
} X%yG{\6:  
:[CV_ME.;  
}$_@yt<{W@  
} 8?Zhh.  
a7g;8t-&  
$INB_/RE  
/* 9n
R\7!_  
**SiteInfoBean.java <- \|>r Q  
*/ ;wwc;wQ'  
package NetFox; c!IZLaVAr9  
A-!e$yz>  
GRcPzneiz  
public class SiteInfoBean { >pF*unC;  
zj7ta[<tr  
~nA k-toJ  
private String sSiteURL; //Site's URL x3y
+=aj  
private String sFilePath; //Saved File's Path Tz1^"tx9  
private String sFileName; //Saved File's Name i(4<MB1a  
private int nSplitter; //Count of Splited Downloading File @j\:K<sk  
:+\0.\K0!  
wtS*-;W  
public SiteInfoBean() ,ua1sTgQ  
{//nSplitter的缺省值为5 B0Df7jr%`>  
//default value of nSplitter is 5 LdZVXp^  
this("","","",5); )ce 6~  
} 0he3[m}Nr  
u''Ce`N  
#*g=F4>t  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _ $a3lR  
{ H$%MIBz>$  
sSiteURL= sURL; ^MpMqm1?8;  
sFilePath = sPath; R,3cJ Y_%  
sFileName = sName; 1GY
Z1iA  
this.nSplitter = nSpiltter; Yc7YNC.  
fl-J:`zyyZ  
C5~~$7k0  
} HPphTu}`  
|^Io
x0A  
O=jLZ2os  
public String getSSiteURL() zM0}(5$m  
{ PK+sGV  
return sSiteURL; ${T/b(NM  
} @;egnXxF<  
6*Z7JiQ0  
.lcp5D[(  
public void setSSiteURL(String value) 2F2Hl  
{ DZqPCMz)^  
sSiteURL = value; QoYEWXT|g  
} pA!-sp
gX  
cKVFykwM  
e\6H.9=  
public String getSFilePath() fOi Rstci  
{ ]?}>D?5  
return sFilePath; |.)LZP,  
} ]^ R':YE  
<@Q27oEuA  
E+\?ptw  
public void setSFilePath(String value) <q7o"NI6FZ  
{ f\2IKpF2  
sFilePath = value;
]o'o v
 
} &GLDoLk6[  
k-ZO/yPo  
\WiCI:  
public String getSFileName() T1C_L?L  
{ -m^-p  
return sFileName; ) ^En  
} rD}g9?ut  
p)SW(pS  
rn-bfzoDS  
public void setSFileName(String value) NO~G4PUM0C  
{ p4P=
T@:  
sFileName = value; > 'R{,1# U  
} 7n5gXiI"  
"}3sL#|z  
PSJj$bt;<+  
public int getNSplitter() ]he~KO[j<  
{ KkUK" Vc  
return nSplitter; *J4!+GD  
} KtaoOe  
af|h4.A  
L-Q8iFW'  
public void setNSplitter(int nCount) #zP-,2!r  
{ @V 'HX  
nSplitter = nCount; %V=%ARP|  
} BvP\c_  
} <6(0ZO%,C!  
Ts.2\-+3  
q|ce7HnK  
/*
20}HTV{v  
**Utility.java >*EZZ\eU!  
*/ j/aJDE(+  
package NetFox; kEh\@x[  
JL,Y9G*]s  
wXUR9H|0(  
public class Utility { o<5`uV!f  
~R;/u")@e  
)1 -<v);  
public Utility() wNUT0+  
{ _WNbuk0  
bpc1>?  
B :%Vq2`  
} 43k'96[2d  
SA'
g`  
//线程睡眠 i@9 qp?eb  
public static void sleep(int nSecond) WD%(RC"Q  
{ &-*l{"7p+%  
try{ P6_Hz!vE  
Thread.sleep(nSecond); V< F&\  
} I3>8B  
catch(Exception e) brTNwRze  
{ H|aFs.SEQ  
e.printStackTrace (); K#k/t"r  
} -. *E<%  
} }a
Oqoi7w  
8Ay7I  
//日志 8(Az/@=n  
public static void log(String sMsg) ~g!!#ad  
{ p l^;'|=M  
System.err.println(sMsg); ,6]ID1o:y  
} uzxwJs'fz  
= 9Yfo,F  
y CHOg  
public static void log(int sMsg) VKPEoy8H  
{ i1x4$}  
System.err.println(sMsg); pT=^
o  
} [.>=>KJ_  
} !BVCuuM>w  
'TYO-'aC  

-n7@r  
/* s O#cJAfuu  
**TestMethod.java bqH [-mu6  
*/ z9 0JZA  
package NetFox; P DY :?/  
<6;M\:Y*T  
pmP~1=3  
public class TestMethod { `]65&hWZL  
~j[?3E4L}  
G$a@}9V  
public TestMethod() n#}@|"J  
{ ///xx/weblogic60b2_win.exe fK:4jl-r  
try{ _xAru9=n^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); vFL$wr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); te[uAJ1 N  
SiteFileFetch fileFetch = new SiteFileFetch(bean); O^\:J2I(  
fileFetch.start(); <N<0?GQ  
} W!HjO;  
catch(Exception e){e.printStackTrace ();} (ORbhjl  
Mo@{1K/9  
hYyIC:PXR  
} K3vZ42n  
[GbrKq(  
/ xv5we~  
public static void main(String[] args) #8XmOJ"W3k  
{ 1$DcE>  
new TestMethod(); (P?|Bk[  
} \X\< +KU  
} a)W|gx6Y  
点击下载更多相关资料