http断点续传简单实现（java)

/* x3+oAb@o/  
**SiteFileFetch.java 9p* gU[  
*/ &C<yfRDu  
package NetFox; )j l8!O7  
import java.io.*; SMr13%KN/  
import java.net.*; Jb_1LZ)]  
`O?T.p)  
@&F@I3`{  
public class SiteFileFetch extends Thread { {=2DqkTD  
G.VuKsP]  
f_^1J  
SiteInfoBean siteInfoBean = null; //文件信息Bean BimjQ;jtI  
long[] nStartPos; //开始位置 ]va>ex$d  
long[] nEndPos; //结束位置 7R.Q Ql  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 WS8+7O'1\  
long nFileLength; //文件长度 6DIZ@oi  
boolean bFirst = true; //是否第一次取文件 3chPY4~A  
boolean bStop = false; //停止标志 [jdFA<Is  
File tmpFile; //文件下载的临时信息 INs!Ame2  
DataOutputStream output; //输出到文件的输出流 ^jB8Q  
RrZM&lXY  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） lf<S_2i  
public SiteFileFetch(SiteInfoBean bean) throws IOException *.-.iY.a]  
{ 1F8 W9b^D  
siteInfoBean = bean; f"u*D,/sS  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <:>SGSE9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &GTI  
if(tmpFile.exists ()) 3f Xv4R;!:  
{ \`V$ 'B{.  
bFirst = false; '7Nr8D4L  
read_nPos(); Cb t{H}I3  
} ]M>9ULQ  
else N]EcEM#  
{ d6{Gt"  
nStartPos = new long[bean.getNSplitter()]; f*{ YFg?*&  
nEndPos = new long[bean.getNSplitter()]; sxKf&p;  
} ?^mi3VM  
`nXVE+E@  
kv,%(en]  
hVT~~n`Rj  
} )5j;KI%t  
V3;.{0k  
]?1Y e8>Y<  
public void run() SnlyUP~P  
{ Pz#7h*;cw.  
//获得文件长度 qSqI7ptA\  
//分割文件 keW~ NM  
//实例FileSplitterFetch PP~rn fE  
//启动FileSplitterFetch线程 0_P}z3(M  
//等待子线程返回 an
w}w!@U  
try{ #PDf,^
 
if(bFirst) HjqB^|z  
{ &c(WE RW?-  
nFileLength = getFileSize(); $mm
up|;(  
if(nFileLength == -1) >h2%[j=  
{ uJHu>M}~  
System.err.println("File Length is not known!"); v[@c*wo  
} 87)zCq  
else if(nFileLength == -2) /){
KOCBl;  
{ ,oxcq?7#4  
System.err.println("File is not access!"); iqQUtE]E_  
} GuZ( &G6*  
else 5ercD  
{ !MDNE*_
 
for(int i=0;i<nStartPos.length;i++) )D'^3)FF  
{ u<q :$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); H.<a`mm8  
} e~ aqaY~}  
for(int i=0;i<nEndPos.length-1;i++) [3l*F  
{ CM)Q&:  
nEndPos = nStartPos[i+1]; g*)K/Z0pJ$  
} u~ ~R9.
 
nEndPos[nEndPos.length-1] = nFileLength; M/?KV9Xk2  
} 9odJr]  
} RCTQhTy=  
v%k9M{  
N"/-0(9[  
//启动子线程 8zLY6@
  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !Fw?H3X!"q  
for(int i=0;i<nStartPos.length;i++) KfBTL!0#  
{ _rV5E  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F/m^?{==~*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -LDCBc"  
nStartPos,nEndPos,i); *#%9Rp2|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PkE5|d*,  
fileSplitterFetch.start(); SvN9aD1  
} {U 'd}Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4Wy<?O2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A7!g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #po5_dE\*  
nEndPos = " + nFileLength); nzjkX4KV  
// fileSplitterFetch[nPos.length-1].start(); Wk:hFHs3  
E_F5(xSA  
}R3=fbe,\  
//等待子线程结束 +$xeoxU>;  
//int count = 0; D'Z|}(d&  
//是否结束while循环 lnovykR  
boolean breakWhile = false; ;U1UFqZ`  
6{[pou&  
Am8x74?  
while(!bStop) I$Qs;- (  
{ 5qg2Zc~  
write_nPos(); +jg9$e"  
Utility.sleep(500); ;fw1
 
breakWhile = true; ky 8ep  
ml@2wGyf  
tNsPB6Z  
for(int i=0;i<nStartPos.length;i++) ,D\GGRw  
{ nA|.t  
if(!fileSplitterFetch.bDownOver) S[tE&[$(p  
{ nf1#tlIJd  
breakWhile = false; IchCACK  
break; hlu:=<B  
} Xi?b]Z  
} 22kpl)vbU  
if(breakWhile) 2,lqsd:xM  
break; "#v=IJy&r  
vHAg-Avc  
7iHK_\tn  
//count++; 2L AYDaS  
//if(count>4) V`adWXu  
// siteStop(); h8\  T  
} th6+
2&B6  
QDpEb=|S  
iv phlw  
System.err.println("文件下载结束！"); n~g)I&  
} ]zO/A4  
catch(Exception e){e.printStackTrace ();} yNm:[bOER  
} Z5c~^jL$-  
/h v4x9  
k3+e;[My+  
//获得文件长度 >7!6nF3x,  
public long getFileSize() tb:L\A^:  
{ %Pksv}  
int nFileLength = -1; l5+gsEux]  
try{ bs9aE<j  
URL url = new URL(siteInfoBean.getSSiteURL()); C^QtSha
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o!:8nXw  
httpConnection.setRequestProperty("User-Agent","NetFox"); >
5R<;#8  
J$~<V IX  
9]t[J_YM  
int responseCode=httpConnection.getResponseCode(); "cTncL  
if(responseCode>=400) [-&L8Un  
{  )1g"?]  
processErrorCode(responseCode); #fj/~[Ajv  
return -2; //-2 represent access is error LqdY Qd51  
} j)t+jcMUI  
& cNy  
jCTAKaq  
String sHeader; +0),xu   
;['[?wk  
0&ByEN99  
for(int i=1;;i++) @!&}}"<  
{ *9)SmSs  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); b3wM;jv  
//Utility.log(in.readLine()); {JV@"t-X3"  
sHeader=httpConnection.getHeaderFieldKey(i); "EU{8b  
if(sHeader!=null) G/%iu;7ZCb  
{ .I}:m%zv  
if(sHeader.equals("Content-Length")) JbB}y'c4}=  
{ 'qdPw%d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2,aPr:]  
break; ++L?+^h  
} c!8=lrT.  
} 3~e8bcb  
else .To;"D;j,  
break; H3{GmV8  
} lnE+Au'  
} ]|_\x
O(  
catch(IOException e){e.printStackTrace ();} < j$#9QQ1  
catch(Exception e){e.printStackTrace ();} Tz2-Bp]h  
(M =Y&M'f  
m]*Bx%-1c  
Utility.log(nFileLength); vK$"# F~  
*5<Sr q'  
1 nvTce  
return nFileLength; '8Phxx|  
} |*RYq2y  
@\&m+;6  
iYnEwAoN;  
//保存下载信息（文件指针位置） LQnkcV  
private void write_nPos() 10#oG{9  
{ +.y .Mp  
try{ \D>$aLO*?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); '03->7V  
output.writeInt(nStartPos.length); %p&k5:4<"#  
for(int i=0;i<nStartPos.length;i++) Av0y?oGH  
{ ~j#~\Ir  
// output.writeLong(nPos); V|)>{Xdn  
output.writeLong(fileSplitterFetch.nStartPos); VL9-NfeqR  
output.writeLong(fileSplitterFetch.nEndPos); Y^%T}yTtq  
} bVmAtm[  
output.close(); ~.%K/=wK@  
} `V[!@b:  
catch(IOException e){e.printStackTrace ();} iut`7  
catch(Exception e){e.printStackTrace ();} 5>J=YLq  
} U|G|l
|Bl  
c:83LZ  
vd`}/~o  
//读取保存的下载信息（文件指针位置） @H!$[m3  
private void read_nPos() g<*BLF  
{ )XQ`M?**M  
try{ ?muzU.h"z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); B= keBO](@  
int nCount = input.readInt(); q_ =b<.;  
nStartPos = new long[nCount]; e6=]m#O9  
nEndPos = new long[nCount];  ]*O/+  
for(int i=0;i<nStartPos.length;i++) ]CU]pK?nq  
{ >r &;3:"  
nStartPos = input.readLong();
9;yn}\N `  
nEndPos = input.readLong(); 74<!&t  
} PNW \*;j  
input.close(); 7^}Ll@  
} /S:F)MO9  
catch(IOException e){e.printStackTrace ();} yBLK$@9  
catch(Exception e){e.printStackTrace ();} 7=@jARW&  
} )pw&c_x  
*%Qn{x  
s08u @  
private void processErrorCode(int nErrorCode) rzp +:  
{ ,mPnQ?  
System.err.println("Error Code : " + nErrorCode); *M7E#bQ5B  
} 1GEK:g2B  
R];Oxe  


elG;jB  
//停止文件下载 UEak^Mm;=2  
public void siteStop() 4Ij-Ilg)%  
{ i?Ss:v^  
bStop = true; ,wwZI`>-  
for(int i=0;i<nStartPos.length;i++) > Oh?%%6  
fileSplitterFetch.splitterStop(); P)dL?vkK  
x*oWa,  
=O|c-k,f@  
} wV?,Z!\Z  
} 3M5#4n\v$  
//负责部分文件的抓取 }U@m*dEG  
**FileSplitterFetch.java 9>/wUQs!]  
*/
iE0ab,OF  
package NetFox; \3Oij^l0  
@|yeqy_:  
2?Ye*-  
import java.io.*; VcK}2<8:+~  
import java.net.*; ^4%Zvl  
-ZW0k@5g  
9Pd*z>s  
public class FileSplitterFetch extends Thread { 0;
,IKXK6X  
s?WCnT  
n{*e 9Aw  
String sURL; //File URL nZR!*$}A  
long nStartPos; //File Snippet Start Position V+?]S  
long nEndPos; //File Snippet End Position GC8}X;((Y  
int nThreadID; //Thread's ID y( r1I[W'  
boolean bDownOver = false; //Downing is over r%Rs0)$yj  
boolean bStop = false; //Stop identical 6VD1cb\lF  
FileAccessI fileAccessI = null; //File Access interface ryO$6L  
S
)He$B$pp  
n$m"]inX  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~Lfcg*  
{ Ct$82J  
this.sURL = sURL; -6Tk<W  
this.nStartPos = nStart; @|bP+8oU  
this.nEndPos = nEnd; g|PC$p-z+  
nThreadID = id; 0f ER*.F  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 F{k+7Ftc  
} Dj-s5pAW  
[%HIbw J  
,]R8(bD)  
public void run() 3E} An%  
{ O`FqD{@V  
while(nStartPos < nEndPos && !bStop) I
 5ag6l  
{ _i}wK?n  
L{gE'jCC  
,xJrXPW  
try{ rl:KJ\*D  
URL url = new URL(sURL); b syq*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G,&%VQ3P>  
httpConnection.setRequestProperty("User-Agent","NetFox"); iNcZ)m/  
String sProperty = "bytes="+nStartPos+"-"; 5IVks
g  
httpConnection.setRequestProperty("RANGE",sProperty); :lcea6iO  
Utility.log(sProperty); 9T2xU3UyY  
?y},,  
(k-YI{D3  
InputStream input = httpConnection.getInputStream(); jm>3bd  
//logResponseHead(httpConnection); Hr;h4J  
&UAe!{E0  
lp&!lb`  
byte[] b = new byte[1024]; jyW[m,#(go  
int nRead; 1S%k  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "u}9@}*  
{ -237Lx$/  
nStartPos += fileAccessI.write(b,0,nRead); $%2_{m_K:p  
//if(nThreadID == 1) h~HB0^|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  ~QG?k  
} fF?6j  
+R$?2  
pLoy  
Utility.log("Thread " + nThreadID + " is over!"); ed~R>F>  
bDownOver = true; V7CoZnz  
//nPos = fileAccessI.write (b,0,nRead); T`L}[?w  
} 744=3v  
catch(Exception e){e.printStackTrace ();} w-
FnE}"l  
} ySX/=T:<;  
} XSD%
t8<LO  
_'iDF  
HFh /$VM  
//打印回应的头信息 l)}t,!M6  
public void logResponseHead(HttpURLConnection con) e9@(/+
 
{ R8sck)k'}  
for(int i=1;;i++) ^"6f\  
{ ~ l )t|'6  
String header=con.getHeaderFieldKey(i); 4 eh=f!(+  
if(header!=null) r#h {$i
W  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >[K?fJ$+  
Utility.log(header+" : "+con.getHeaderField(header)); MQ
w9X  
else 
u^Sv#K X  
break; -q2MrJ*  
} $ad&#q7  
} =y;@?=T  
19y 0$e_V  
OXtBJYe  
public void splitterStop() B3b,F
#  
{ OD4W}Y.  
bStop = true; jb@\i@-  
} Qilj/x68  
zeOb Aw1O  
(&Q)EBdm  
} H1UL.g%d=  
Z`xyb>$  
gduxA/aT  
/* |HgfV@Han  
**FileAccess.java uB+9dQ  
*//文件访问(定位，写) QT}iaeC1i  
package NetFox; &-F"+v,+  
import java.io.*; kk
fCAM  
RjtC:H&XZ  
YRa4W.&Yn  
public class FileAccessI implements Serializable{ Uz>Yn&{y6  
Z[;#|$J  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *PcVSEP/0  
RandomAccessFile oSavedFile; @,6ST0xT (  
long nPos; &wGg6$  
rt;gC[3\  
b+$o4l/x  
public FileAccessI() throws IOException Ec.)!Hu  
{ +FBi5h  
this("",0); M)=|<h"F  
} ]L]T>~X`  
|>JmS  
24|<<Xn  
public FileAccessI(String sName,long nPos) throws IOException 3;D?|E]1  
{ a(Sv,@/  
oSavedFile = new RandomAccessFile(sName,"rw"); d<Dn9,G  
this.nPos = nPos; Lw*1 .~  
oSavedFile.seek(nPos); '}zT1F* p=  
} *^6k[3VY  
nOuN|q=C  
2mOfsn d@  
public synchronized int write(byte[] b,int nStart,int nLen) cUM_ncYOP  
{ ] zIfC>@R  
int n = -1; yy))Z0E5  
try{ =#'+"+lQ }  
oSavedFile.write(b,nStart,nLen); Ns
~g+C9  
n = nLen; G;9|%yvd8  
} % &+|==-  
catch(IOException e) e5qvyUJM  
{ {jUvKB_x  
e.printStackTrace (); Ps|QW  
} "o<D;lO  
yUj;4vd  
o3= .T+B  
return n; '}fel5YV  
} 5Q;dnC  
JchA=n  
AG=9b  
} 69OET_AS>  
XWf7"]%SX  
@2|G|C/]O}  
/* W9+h0A-  
**SiteInfoBean.java y8D 8Y8B  
*/ >+f'!*%7He  
package NetFox; F]P
ul|.l  
lk~dgky@  
q"l>`KCG`  
public class SiteInfoBean { HMQ'b(a'  
{'&8`d  
_32/WQF6  
private String sSiteURL; //Site's URL LNbx3W oC  
private String sFilePath; //Saved File's Path +}\29@{
W  
private String sFileName; //Saved File's Name i63?"  
private int nSplitter; //Count of Splited Downloading File vnF g%M!  
i!y\WaCp  
d^_itC;-,  
public SiteInfoBean() f0g6g!&gf  
{//nSplitter的缺省值为5 =X<)5IS3  
//default value of nSplitter is 5 Hq79/wKj  
this("","","",5); QZ:v  
} ;7)OSGR
 
AV9:O{  
P)4x  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 89ZDOji?O  
{ i"KL;t[1  
sSiteURL= sURL; AwA1&mh  
sFilePath = sPath; )m)h/_  
sFileName = sName; JJ)y2
 
this.nSplitter = nSpiltter; K"G(?<>~4c  
f};!m=b  
#<D@3ScC  
} US"2O!u  
rg"TJ"Q-  
J~fuW?a]r  
public String getSSiteURL() EGr|BLl  
{ -.^=Z!=M  
return sSiteURL; :R{x]sv  
} u;QH8LK  
4$qNcMdz  
[Aa[&RX+9  
public void setSSiteURL(String value) )|MIWgfWN  
{ ;}n|,g>  
sSiteURL = value;
'[ @F%  
} Cbazwq  
eR(\s_`  
sf<Q#ieTxY  
public String getSFilePath() / O|Td'Z  
{ k q/t]%(  
return sFilePath; 6zELe.tq  
} AfuXu@UZ_/  
nmTm(?yE  
Q|6Ls$'$  
public void setSFilePath(String value) =I %g;YK  
{ z0=Rp0_W  
sFilePath = value; YLD-SS[/>  
} 6yy|V~5  
<=#lRZW[z  
)R8%wk?2  
public String getSFileName() A!Knp=Gw  
{ O-y6!u$6&  
return sFileName; ?r^ hmu"a  
} hg$qbeUl  
ecM4]U  
"``W6W-(  
public void setSFileName(String value) ^uKnP>*l
 
{ Fc34Y0_A  
sFileName = value; ppPG+[cz  
} pjaiAe!k  
:<'i-Ur8  
A73V6"  
public int getNSplitter() ~| 4U@  
{ tn(?nQN3  
return nSplitter; a!TBk=P  
} GhSL%y  
{QIS411  
YlZYS'_  
public void setNSplitter(int nCount) u=_b
M2;~Z  
{ Z%,\+tRe  
nSplitter = nCount; [q0_7  
} Wq=ZU\Y  
} 4*@G&v?n  
+1E?He:iQ  
X|lElN  
/* jsZiARTZRl  
**Utility.java c,3'wnui  
*/ Ba"^K d`  
package NetFox; XvfcPI6  
lp37irI:  
^g}gT-l%  
public class Utility { SdjUhR+o  
P3,Z5|)  
D[>XwL  
public Utility() w /Bn2bD  
{ 60U{ e}Mkb  
(R;) 9I\  
X\c1q4oB[  
} ?9wFV
/  
ZTgAZ5_cz  
//线程睡眠 -@gJqoo>  
public static void sleep(int nSecond) !_
^{udB}  
{ h=iA
;B^>  
try{ +[X.-,yW  
Thread.sleep(nSecond); $~w@0Yl  
} xy-$v   
catch(Exception e) +7lRP)1R  
{ A
/Fs?m{7U  
e.printStackTrace (); [i<$ZP
  
} #um1?V  
} ]sm0E@1  
`/gEKrhL-  
//日志 r+V(1<`2X  
public static void log(String sMsg) X,iuz/Q  
{ VAF:Z  
System.err.println(sMsg); mhJOR'2  
} f/IRO33  
WW8YB"  
"x=@,*Bk  
public static void log(int sMsg) a\[fC=]r:  
{ =A6u=  
System.err.println(sMsg); ,,C~j`F  
} ]Nd'%M  
} "PDSqYA  
sGDrMAQt  
UtGd/\:  
/* &]"_pc/>m  
**TestMethod.java ]~g|SqPA@  
*/ b$`4Nn|  
package NetFox; )8N)Z~h  
$Zu4tuXA  
CDTk  
public class TestMethod { IpaJ<~ p  
U0|j^.)  
D^R! |K/  
public TestMethod() pg}DC0a  
{ ///xx/weblogic60b2_win.exe EJ &ZZg  
try{ >*Qk~kv<%  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); tB(X`A.|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); eQ)ioY  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E/ed0'|m  
fileFetch.start(); WG[0$j  
} FUTyx"   
catch(Exception e){e.printStackTrace ();}  V\7u  
)*L?PT  
MgK(gL/&[  
} B& f~.UH  
zKAyfn.A  
=B{$U~}  
public static void main(String[] args) 5A=xFj{  
{ B8#f^}8  
new TestMethod(); 7_'k`J@_  
} ^MWW,`  
} LM`tNZ1Fc!  
点击下载更多相关资料