http断点续传简单实现（java)

/* j~;kh_  
**SiteFileFetch.java sgxD5xj}4  
*/ p*ic@n*G  
package NetFox; uKF)'gj  
import java.io.*; xp68-&  
import java.net.*; ~u^MRe|`  
QKVFH:"3  
GB&^<@  
public class SiteFileFetch extends Thread { -RK R.,  

sCrOdJ6|  
EG;y@\]  
SiteInfoBean siteInfoBean = null; //文件信息Bean fC<pCdsg  
long[] nStartPos; //开始位置 Ng 3r`S"_<  
long[] nEndPos; //结束位置 r&0IhE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =Ul{#R z  
long nFileLength; //文件长度 Mv%"aFC  
boolean bFirst = true; //是否第一次取文件 41oXOB  
boolean bStop = false; //停止标志 [19QpK WM  
File tmpFile; //文件下载的临时信息 HCIS4}lQ  
DataOutputStream output; //输出到文件的输出流 gAxf5A_x)  
yR'%UpaE  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Z^_-LX:%  
public SiteFileFetch(SiteInfoBean bean) throws IOException q7k
E+z  
{ ?#]wxH,  
siteInfoBean = bean; kh5VuXpe  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 57~/QEdy  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); c80!Ub@  
if(tmpFile.exists ()) DGrk}   
{ "x~su?KiA  
bFirst = false; [==x4Nb  
read_nPos(); Yk @/+PE  
} -?}Z0e(w
 
else QTLGM-Z  
{ Fofe
Q  
nStartPos = new long[bean.getNSplitter()]; ^X\SwgD2w  
nEndPos = new long[bean.getNSplitter()]; gT0N\oU"  
} '5; /V  
a]4h5kJ';  
<yg!D21Y  
~Kiu" g  
} -)E nr6  
qS?uMms7w  
@0[#XA_>  
public void run() dh0nB  
{ Sece#K2J|  
//获得文件长度 Bp9_\4  
//分割文件 a,`f`;\7N%  
//实例FileSplitterFetch ^=@`U_(,G  
//启动FileSplitterFetch线程 D4
IP$pAD  
//等待子线程返回 ttfCiP$  
try{ S!6 ? b5  
if(bFirst) H7?Sd(U  
{ PW QRy  
nFileLength = getFileSize(); 
0 P2lq  
if(nFileLength == -1) a%XF"
*^v  
{ reI4!,x  
System.err.println("File Length is not known!"); @wPyXl  
} yBkcYHT  
else if(nFileLength == -2) a1 v%G  
{ 5KgAY;|  
System.err.println("File is not access!"); tYUg%2G  
} mbZn[D_zi  
else 5iZx -M  
{ %@MO5#)NI  
for(int i=0;i<nStartPos.length;i++) v7b+  
{ GWW#\0*Bn  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *6/OLAkyF  
} c0f8*O4i  
for(int i=0;i<nEndPos.length-1;i++) Wf{&D>  
{ <pIel   
nEndPos = nStartPos[i+1]; ]QSQr*  
} D $&6 8  
nEndPos[nEndPos.length-1] = nFileLength; GV8`.3DBOF  
} #&,~5  
} 7Sl"q=>  
o7kQ&w  
<V1y^EW0  
//启动子线程 e!N%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Pj^O8  
for(int i=0;i<nStartPos.length;i++) r*f:%epB%  
{ -Ic<.ix  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R/P9=yvg0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nj=nSD  
nStartPos,nEndPos,i); n'9&q]GN|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "sJ@_lp  
fileSplitterFetch.start(); vRMGNz_P7[  
} oD3Q{e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lS |:4U.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |\T!,~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }WnoI2  
nEndPos = " + nFileLength); 6F; |x  
// fileSplitterFetch[nPos.length-1].start(); 51'{Jx8  
=VGRM#+D  
4XN
kto  
//等待子线程结束 GzjC;+W  
//int count = 0; suE#'0K  
//是否结束while循环 ~}g)N  
boolean breakWhile = false; ,+!|~1  
j$Vtd&  
\OVw  
while(!bStop) 4?Qc&e{5  
{ [m6%_3zV  
write_nPos(); ,lQfsntk'  
Utility.sleep(500); u"-."_  
breakWhile = true; qkD9xFp  
\:>eZl?  
T1M>N  
for(int i=0;i<nStartPos.length;i++) S#l)|c_~  
{ <ELqj2`
c  
if(!fileSplitterFetch.bDownOver) @T)>akEOt  
{ I 8 Ls_$[  
breakWhile = false; v<E_n;@9k  
break; %:Y'+!bX  
} wj9Hh  
} BV eIj }  
if(breakWhile) N[wyi&m4  
break; )]{&  
Rip[  
' eH Fa  
//count++; =z9FjK  
//if(count>4) _SqUPTb"u  
// siteStop(); DHh30b$c  
} .1h1J   
K!;>/3Y2-  
`.YMbj#T  
System.err.println("文件下载结束！"); 2x:aMWh  
} p/Ri|FD6  
catch(Exception e){e.printStackTrace ();} uY:u[  
} =EUi|T4:  
xcC^9BAj  
\g:Bg%43h  
//获得文件长度 AUPTtc`#Y  
public long getFileSize() zN>tSdNkI-  
{ 92g&,Wb  
int nFileLength = -1; PZhpp"  
try{ qWw{c&{Q],  
URL url = new URL(siteInfoBean.getSSiteURL()); ]`\~(*;[W9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qrY]tb^K  
httpConnection.setRequestProperty("User-Agent","NetFox"); @mu=7_$U  
?#VkzT  
+tp@Tb  
int responseCode=httpConnection.getResponseCode(); dwmZ_m.  
if(responseCode>=400) pLsJa?}R  
{ XXC(R  
processErrorCode(responseCode); )X5en=[)O  
return -2; //-2 represent access is error H6i;MQ  
} Q#sLIZ8=  
,Cj` 0v#  
'L ]k\GO  
String sHeader; <jtu/U]78|  
lvIdYf$?  
THz=_
L6  
for(int i=1;;i++) K5:>  
{ 8aa`0X/6  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZqJyuTPv  
//Utility.log(in.readLine()); h|XLL|:  
sHeader=httpConnection.getHeaderFieldKey(i); xJF}6yPm@  
if(sHeader!=null) V.~C.x  
{ ec"+Il  
if(sHeader.equals("Content-Length")) Bey|f/ <  
{ w$[ck=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); KU)~p"0[6]  
break; \,yX3R3}.~  
} rT28q.  
} F;<cG`|Rx  
else <#No t1R  
break; OjBg$f~0F  
} ip2BvN&  
} z*O
Q4_  
catch(IOException e){e.printStackTrace ();} kc}&\y  
catch(Exception e){e.printStackTrace ();} VXIB9 /*i  
0v'FE35~s  
2^T`> ?{X  
Utility.log(nFileLength); tU, >EbwO  
e$=0.GWT  
,5/zTLd   
return nFileLength; zIh`Vw,t0  
} A"R5Fd%6pc  
FvV:$V|  
\KT}T  
//保存下载信息（文件指针位置） [{cMEV&  
private void write_nPos() =U_O;NC  
{ Fun+L@:;  
try{ M3/_E7Qoj  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sU 5/c|&  
output.writeInt(nStartPos.length); Qlgii_?#@  
for(int i=0;i<nStartPos.length;i++) dsD!)$  
{ O'~;|-Z<  
// output.writeLong(nPos); ecG,[1];  
output.writeLong(fileSplitterFetch.nStartPos); |XoW Z,K  
output.writeLong(fileSplitterFetch.nEndPos); kPg| o3H  
} X!ad~bt  
output.close(); !pG_MO  
} k^v P|*eu  
catch(IOException e){e.printStackTrace ();} V [KFZSA  
catch(Exception e){e.printStackTrace ();} '+*{u]\  
} pv9Z-WCix$  
+YK/^;Th  
wJKP=$6n_  
//读取保存的下载信息（文件指针位置） P<{N)H 2r  
private void read_nPos() ^i!6q9<{e  
{ %^ z##7^  
try{ O0Sk?uJ<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^ ;XJG9a0\  
int nCount = input.readInt(); fkmN?CU{1%  
nStartPos = new long[nCount]; sGs_w:Hn  
nEndPos = new long[nCount]; ,z+7rl  
for(int i=0;i<nStartPos.length;i++) fNTe_akp  
{ RNB ha&  
nStartPos = input.readLong(); C!Oz'~l  
nEndPos = input.readLong(); .PJ
CBTe  
} LIZsDTU  
input.close(); XAF*jevr  
} qH1&tW$  
catch(IOException e){e.printStackTrace ();} ~v+A6N:qC  
catch(Exception e){e.printStackTrace ();} NwPC9!*  
} smTPca)7s  
hxQx$  
EvQMt0[?EW  
private void processErrorCode(int nErrorCode) zUCtH*  
{ c^s%t:)K  
System.err.println("Error Code : " + nErrorCode); Wz]ny3K[.  
} k-N` h  
`;vJ\$-<  
u>W:SM  
//停止文件下载 />q?H)6  
public void siteStop() 1so9w89  
{ ;+-Dg3  
bStop = true; sF+Bu'9
A  
for(int i=0;i<nStartPos.length;i++) 5h6c W  
fileSplitterFetch.splitterStop(); y-i6StJ  
eW>Y*l%B  
>wOqV!0<  
} e qzmEg  
} OX!<{9o  
//负责部分文件的抓取 =2rkaBFC  
**FileSplitterFetch.java 1?}5.*j<  
*/ u|}p3-z|Y  
package NetFox; 0M_~@E*&  
aH!2zC\:T  
1o*eu&@  
import java.io.*; ZIo%(IT!c  
import java.net.*; c&AJFED]<  
?1kXV n$  
xYUC|c1Q9  
public class FileSplitterFetch extends Thread { XzF-g*e  
k9Xv@v  
F&= X/  
String sURL; //File URL K.T.?ug;:  
long nStartPos; //File Snippet Start Position GjD^\d/  
long nEndPos; //File Snippet End Position !:<(p  
int nThreadID; //Thread's ID #Z)8
,N  
boolean bDownOver = false; //Downing is over lk?@ =U~  
boolean bStop = false; //Stop identical 7)U08"  
FileAccessI fileAccessI = null; //File Access interface 'W2B**}  
?7]UbtW[  
/ 80Q  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;Or]x?-  
{ q{:]D(   
this.sURL = sURL; pDloew  
this.nStartPos = nStart; ,6iXlch  
this.nEndPos = nEnd; Je1'0h9d  
nThreadID = id; Q?uHdmY*X  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C@#KZ`c)  
} N!#0O.6  
R$Or&:E ^  
K#>@T<  
public void run() \J0fr'(S  
{ E[8R )xC@  
while(nStartPos < nEndPos && !bStop) 2#hfBJg@  
{ LI`H,2Km  
[')C]YQb=  
,N`cH\  
try{ Y;dQLZCC  
URL url = new URL(sURL); eF%>5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cFF'ygJ/  
httpConnection.setRequestProperty("User-Agent","NetFox"); BV@xE  
String sProperty = "bytes="+nStartPos+"-"; )] C"r_  
httpConnection.setRequestProperty("RANGE",sProperty); io1hUZ  
Utility.log(sProperty); AwQ7Oz|(  
}S_#*N)i  
zY^QZceq"  
InputStream input = httpConnection.getInputStream(); X]T&kdQ6q  
//logResponseHead(httpConnection); (- QvlpZ  
31> $;"  
\lBY4j+;  
byte[] b = new byte[1024]; dPmtU{E<M  
int nRead; e_v_y$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )@,zG(t5;  
{ }JlrWJRi  
nStartPos += fileAccessI.write(b,0,nRead); L$ki>._i\  
//if(nThreadID == 1) d09qZj>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q]7}"B&  
} L55VS:'  
pX LXkF?  
S+*g  
Utility.log("Thread " + nThreadID + " is over!"); ZKp9k6  
bDownOver = true; T5gL  
//nPos = fileAccessI.write (b,0,nRead); #P)(/>nF  
} u P&<  
catch(Exception e){e.printStackTrace ();} Mr6q7  
} D%%@+3a  
} D]StDOmM  
"
t!_bma  
"eb+
O  
//打印回应的头信息 XKQ\Ts2<k  
public void logResponseHead(HttpURLConnection con) P'<D0   
{ 31)eDs  
for(int i=1;;i++) _
>=QZ`!r  
{ 'U/X<LCl  
String header=con.getHeaderFieldKey(i); 'irHpN6n  
if(header!=null) X7Z=@d(
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); id:6O+\  
Utility.log(header+" : "+con.getHeaderField(header)); iR39lOr  
else \>N"{T  
break; yZyB.wT  
} oH>G3n|U^  
} _p^&]eQ+k#  
agUdPl$e\  
.jK,6't^  
public void splitterStop() %SKJ#b  
{  57`*5X  
bStop = true; YU6D;  
} 9J4gDw4<  
55K(]%t  
l1uv]t <  
} $_orxu0W  
7S.E,\Tws  
';iLk[  
/* o)r%4YOL  
**FileAccess.java <R.Ipyt.  
*//文件访问(定位，写) 2}xvM"k=k  
package NetFox; G+V?c1Me  
import java.io.*; :211T&B%A_  
5JggU  
GX,)~Syw*  
public class FileAccessI implements Serializable{ v~`'!N8  
{O"N2W  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 oF {
u  
RandomAccessFile oSavedFile; -(1GmU5v(  
long nPos; D9/PVd&#  
OkfnxknZ|  
qku}cWD9/_  
public FileAccessI() throws IOException t^5xq8w8  
{ yDmx)^En  
this("",0); \l71Q/y6u`  
} H*R4AE0  
XZH\HK)K-]  
6)j/"9oY  
public FileAccessI(String sName,long nPos) throws IOException .z}*!   
{ Uxb>)36I  
oSavedFile = new RandomAccessFile(sName,"rw"); W0;
MGBfb  
this.nPos = nPos; (_Ky'.  
oSavedFile.seek(nPos); m>&
:)K}m  
} * G0I2  
$-p#4^dg  
kpLx?zW--q  
public synchronized int write(byte[] b,int nStart,int nLen) TJ+,G4z  
{ >^TcO  
int n = -1; {}DoRpq=  
try{ :{'%I#k2  
oSavedFile.write(b,nStart,nLen); .X;DI<K  
n = nLen; Qoom[@$  
} 6u[ B}%l  
catch(IOException e) 07#e{   
{ ds "N*\.  
e.printStackTrace (); 9D,/SZ-v  
} rJw Ws  
U])$#/ v  
vHM,_I{  
return n; s~n@|m9k  
} ^udl&>  
3u@=]0ZN  
0$:jZ/._  
} z 8y.@<6  
y41,T&ja  
5Zy%Nam'gN  
/* W+`T:Mgh  
**SiteInfoBean.java $c1x
h.  
*/ =.\PG[  
package NetFox; ?*dt JL  
ck\TTNA  
`g^bQx  
public class SiteInfoBean { -APbN(Vi  
:O/QgGZN$  
R}T\<6Y  
private String sSiteURL; //Site's URL X6G2$|  
private String sFilePath; //Saved File's Path }[b3$WZ  
private String sFileName; //Saved File's Name D0VbD" y  
private int nSplitter; //Count of Splited Downloading File 6`V~cVu  
d$#DXLA\P  
YF68Ax]  
public SiteInfoBean() Ac8t>;=&  
{//nSplitter的缺省值为5 vNSeNS@jxC  
//default value of nSplitter is 5 Ee097A?1vj  
this("","","",5); gH:+$F
A  
} $q 9dkt  
$b`~KMO  
4H_Q
Q6  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e=sV>z>  
{ Yc2dq e>  
sSiteURL= sURL; 0}q
nq"  
sFilePath = sPath; Jm[_X  
sFileName = sName; +V9<ug6T  
this.nSplitter = nSpiltter; PS'SIX  
1g>>{ y  
++Fv )KY@  
} /y[zOT6  
"/0Vvy_|  
L7PMam  
public String getSSiteURL() W_RN@O  
{ ,lb >  
return sSiteURL; ^2\-zX!bt  
} ,?(U4pzX  
V|j{#;  
.M([
n-  
public void setSSiteURL(String value) 9^1li2zk{  
{ 5nS}h76mZ  
sSiteURL = value; s7"5NU-  
} Y_,Tm  
d]+2rt}]hL  
z6uHe{|  
public String getSFilePath() *yqke<o9)  
{ Wo7`gf_(  
return sFilePath; 5Mz6/&`  
} vEC#W43l  
.Zm de*b  
*^i"q\n5(  
public void setSFilePath(String value) 1HBWOV7z.?  
{ bEB9J- Q  
sFilePath = value; +O!4~k^  
} (o518fmR  
+6Ye'IOG  
9"cyZO  
public String getSFileName() a Juv{  
{ @Zw[LIQ*  
return sFileName; mu$rG3M  
} (7w95xI  
K:54`UJ  
v(~EO(n.  
public void setSFileName(String value) rp,Us#>6  
{ NuR3]Ja\0  
sFileName = value; tOxTiaa=  
} 04#<qd&ob@  
CG]/.  
7=a=@D[  
public int getNSplitter() 4azqH;i  
{ lQ!(lPh  
return nSplitter; ~ugH2jiB  
} Y lhKP;  
=k##*%  
{Lugdf'  
public void setNSplitter(int nCount) u-@;Q<v$  
{ k|3hs('y|  
nSplitter = nCount; cQrXrij;!  
} l0=VE#rFl  
} NfND@m{/  
', P_a,\  
x\aCZ  
/* =+w/t9I[  
**Utility.java &/8B(0<  
*/ qflOi8  
package NetFox; 1^tM%2rP'  
OXS.CFZM  
7[:?VXQ  
public class Utility { l
._g[qa  
=4 NKXP~C  
$J=`fx  
public Utility() {=6CL'_  
{ Qq3>Xv <  
fU|4^p)  
-FQc_k?VF  
} iHeu<3O  
:;KQ]<  
//线程睡眠 wQ?Z y;/S  
public static void sleep(int nSecond) }fL ]}&  
{ H $mZ?  
try{ ufo\p=pGG  
Thread.sleep(nSecond); &Xi]0\M)  
} lm|s
%  
catch(Exception e) m'WGK`WIm  
{ BFZ\\rN`  
e.printStackTrace (); ?I"FmJ;
 
} ^+x,211f  
} ]-jaIvM  
5?*Iaw  
//日志 4@=[rZb9  
public static void log(String sMsg) P5__[aTD  
{ 00pe4^U  
System.err.println(sMsg); x\8gb
#8  
} zQoJ8i>  
8=u88?Bh  
\ESNfL5  
public static void log(int sMsg) 5MK.>3fE  
{ )}@Z*.HZL  
System.err.println(sMsg); +>Pq]{Uf1j  
} j-zWckT{  
} 'j;i4ie>*x  
?dmwz4k0  
y\R-=Am".  
/* #rQT)n  
**TestMethod.java \jr-^n]  
*/ r{wf;5d(  
package NetFox; Ymm*p,`  
_ygdv\^Tet  
.J?RaH{i  
public class TestMethod { ik5"9b-\<  
I5E+=.T*ar  
et<@3wyd]  
public TestMethod() ]F #0
to  
{ ///xx/weblogic60b2_win.exe f{U,kCv  
try{ |nY+Nen7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); j-v/;7s/B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Sg1,9[pb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); m}t`43}QE  
fileFetch.start(); rE
oOv  
} 0yxwsBLy  
catch(Exception e){e.printStackTrace ();} @B9#Hrc  
w:2yFC  
]W7&ZpF  
} Si68_]:^  
n/^QPR$>.  
}[OEtd{  
public static void main(String[] args) H>wXQ5?W;  
{ D0yH2[j+  
new TestMethod(); o<rbC < U  
} S"/gZfxer  
} `+(4t4@ew  
点击下载更多相关资料