http断点续传简单实现（java)

/* -Rwx`=6tV  
**SiteFileFetch.java ,FwJ0V  
*/ HF<h-gX  
package NetFox; z~th{4#E;  
import java.io.*; e!ql8wbp  
import java.net.*; A[`2Mnj  
!-m 'diE  
& h\!#X0  
public class SiteFileFetch extends Thread { *mz-g7  
!E6QED"  
N<O<wtXIj  
SiteInfoBean siteInfoBean = null; //文件信息Bean iB}*<~`.Eg  
long[] nStartPos; //开始位置 RBLOc$2  
long[] nEndPos; //结束位置 [ut[W9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 X2E=2tXl`7  
long nFileLength; //文件长度 3TRG] 5  
boolean bFirst = true; //是否第一次取文件 0_N.s5~N  
boolean bStop = false; //停止标志 /bF>cpM  
File tmpFile; //文件下载的临时信息 RgVnx]IF  
DataOutputStream output; //输出到文件的输出流 A*{CT>  
+`ug?`_  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） hGcu(kAC,  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9TZ6c  
{ w8bvqTQ  
siteInfoBean = bean; r&_e3#]*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (K('@W%\?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /z)Nz2W  
if(tmpFile.exists ()) Ab8Ke|fA  
{ CY\D.Eow  
bFirst = false; <cFj-Y
s(T  
read_nPos(); M6j~`KSE  
} !xU[BCbfYV  
else lV9  
{ !8YA1 o  
nStartPos = new long[bean.getNSplitter()]; >=86*U~  
nEndPos = new long[bean.getNSplitter()]; +(Jh$b_  
} VNs3.  
;?y~ h$  
#itZ~tol  
}tQ^ch;Q  
} _:%i6c*"  
d(K}v\3!  
Z^J7r&\V  
public void run() \zeuvD  
{ >2ha6A[  
//获得文件长度 2|&SG3e+(I  
//分割文件 MS]Q\g}U  
//实例FileSplitterFetch 6(>,qt,9S  
//启动FileSplitterFetch线程 /CUBs!  
//等待子线程返回 YRCOh:W*  
try{ R7A:K]iJ5  
if(bFirst) HP\5gLVXY  
{ vSY YetL  
nFileLength = getFileSize(); 1--Ka&H  
if(nFileLength == -1) eCiI=HcW;  
{ gfKv$~  
System.err.println("File Length is not known!"); NieNfurG%  
} %LuA:{EVD  
else if(nFileLength == -2) M^lP`=sSv  
{ oPVt qQ  
System.err.println("File is not access!"); r^{Bw1+  
} '>HLE)l  
else  ijDXh y  
{ m ?*h\NaB  
for(int i=0;i<nStartPos.length;i++) ?Iu=os>*  
{ ff]fN:}V  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r[wjE`Z/T  
} !3{;oU%*  
for(int i=0;i<nEndPos.length-1;i++) _M^^0kf  
{ [c XSk  
nEndPos = nStartPos[i+1]; j<k-w  
} [ P,gEYk  
nEndPos[nEndPos.length-1] = nFileLength; y#
= j{  
} FV{XPr%   
} "ji+~%`^[t  
L#%)@  
Cu_-QE  
//启动子线程 n(i/jW~0w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; rM? J40&.  
for(int i=0;i<nStartPos.length;i++) M@Ti$=  
{ v57<b&p26  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F3tIJz>3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Qkw?QV-`k  
nStartPos,nEndPos,i); k9;t3-P  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %j2$ ezud  
fileSplitterFetch.start(); 3#Iq5vT  
} YABi`;R]'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), de;CEm<n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Vt,P.CfdC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", zZP/C   
nEndPos = " + nFileLength); 5#y_EpL"  
// fileSplitterFetch[nPos.length-1].start(); Zy.3yQM9i  
B*9?mcP\  
?6HnN0A)  
//等待子线程结束 >x6)AH.  
//int count = 0; 5tk7H2K^<  
//是否结束while循环 *!j!o%MB  
boolean breakWhile = false; $/$Hi U`.  
6J">@+  
saDu'SmYV  
while(!bStop) ~=I:go  
{ y0p\Gu;3j  
write_nPos(); fWb+08}C  
Utility.sleep(500); ^Pah\p4bj  
breakWhile = true; 2.\"Q  
Y/?z8g'p  
\#I
Kirf?  
for(int i=0;i<nStartPos.length;i++) 3`)ej`  
{ UFC^lv  
if(!fileSplitterFetch.bDownOver) X\>/'fC$  
{ qz.l  
breakWhile = false; 9Q*:II  
break; qe22 kE#  
} bR;.KC3C
 
} 'Hs*  
if(breakWhile) 4?bvJJuf)  
break; 7-C])9  
=pTTXo  
4TYtgP1  
//count++; j WMTQLE.  
//if(count>4) Wc,`L$Jx  
// siteStop(); :DeJnE  
} Ypxp4B  
=LgMG^@mu  
s%8,'3&  
System.err.println("文件下载结束！"); 8'NT_NPNb  
} fsWIz1K  
catch(Exception e){e.printStackTrace ();} nrX+ '  
} ;]bW  
'&2-{Y [!  
P]OUzI,  
//获得文件长度 LFr$h`_D5  
public long getFileSize() o,S(;6pDJ  
{ %$'fq*8b  
int nFileLength = -1; t*dq*(3"c  
try{ a7=lZZ?  
URL url = new URL(siteInfoBean.getSSiteURL()); rQJ\Y3.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f0R+Mz8{  
httpConnection.setRequestProperty("User-Agent","NetFox"); V-E 77u6{0  
S<-5<Pg  
9}L2$^#,NA  
int responseCode=httpConnection.getResponseCode(); jc\y{I\  
if(responseCode>=400) /5Vv5d/Z4!  
{ X?;iSekI4  
processErrorCode(responseCode); C\OZs%]At  
return -2; //-2 represent access is error %|1s9?h7\  
} id" l"  
M%RH4%NZ0  
&pR 8sySu  
String sHeader; _Vf>>tuW  
#?,"/Btq  
TtH!5{$s  
for(int i=1;;i++) #sk~L21A  
{ 2E`mbT,v&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %NTJih`  
//Utility.log(in.readLine()); kP5G}Bp  
sHeader=httpConnection.getHeaderFieldKey(i); nLC5FA7<  
if(sHeader!=null) c=QN!n:  
{ -@Urq>^v T  
if(sHeader.equals("Content-Length")) Jr= fc*f  
{ [LUqF?K&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =BJe}AV  
break; bTZ.y.sI  
} =+I-9=  
} <M}O&?N 8x  
else g/\
cN(X  
break; 2@
@evQ  
} P2|+7D:  
} uu"hu||0_  
catch(IOException e){e.printStackTrace ();} k@h0 }%  
catch(Exception e){e.printStackTrace ();} P=L@!F+s  
5uOz#hN  
@,-D P41g  
Utility.log(nFileLength); O{Mn\M6  
shP}T[<  
F2
ISg'  
return nFileLength; z#rp8-HUDS  
} OVc)PMp  
2-Wy@\  
euW   
//保存下载信息（文件指针位置） SJlE!MK  
private void write_nPos() +_u~Np  
{ ^4'!B +}F  
try{ ~jmI`X/  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ao[yHcAs  
output.writeInt(nStartPos.length); [tElt4uG  
for(int i=0;i<nStartPos.length;i++) ^]~!:Ej0  
{ x8~*+ j  
// output.writeLong(nPos); k g Rys  
output.writeLong(fileSplitterFetch.nStartPos); OdNcuiLa  
output.writeLong(fileSplitterFetch.nEndPos); Zm7,O8  
} KmM:V2@A$  
output.close(); NV@$\<  
} m6]6!_  
catch(IOException e){e.printStackTrace ();} JNJ6HyCU  
catch(Exception e){e.printStackTrace ();} '5~l{3Lw  
} b`,Sd.2=('  
' I!/I  
4HX;9HPHE<  
//读取保存的下载信息（文件指针位置） UI%4d3   
private void read_nPos() !(viXV5  
{ zMBGpqdP  
try{ UO!} 0'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); e$JC
ak=  
int nCount = input.readInt(); t}?-ao  
nStartPos = new long[nCount]; bR~5 :A^  
nEndPos = new long[nCount];  Zy8tI#  
for(int i=0;i<nStartPos.length;i++) 5zkj;?s  
{ ]VE3u_kR  
nStartPos = input.readLong(); o~q.j_Sa  
nEndPos = input.readLong(); s.n:;8RibP  
} qDz[=6BF  
input.close(); x;-D}#  
} }UQ,B  
catch(IOException e){e.printStackTrace ();} !c-MC|  
catch(Exception e){e.printStackTrace ();} j]]5&u/l  
} n2Mpo\2  
pG"hZB3)  
7Cbr'!E\_V  
private void processErrorCode(int nErrorCode) :i@ $s/  
{ $b2~H+u(  
System.err.println("Error Code : " + nErrorCode); T!HAE#xC  
} 5,V*aP  
"r3h+(5  
Y6d~hLC  
//停止文件下载 v\qyDZVV  
public void siteStop() fX6pW%Q'6  
{ &^uaoB0  
bStop = true; Ro<x#Uo  
for(int i=0;i<nStartPos.length;i++) [McqwU/Q  
fileSplitterFetch.splitterStop(); a"T+CA  
LP'q$iB!  
^N 4Y*NtV7  
} g)D@4RM  
} x K\i&A  
//负责部分文件的抓取 : yq2 XE%r  
**FileSplitterFetch.java  6E:H  
*/ /C5py&#-I  
package NetFox; 8Gy*BpmJn  
;l `Ufx  
sG[qlzR=8  
import java.io.*; J$sp6g>K  
import java.net.*; s{V&vRr  
8Q{9AoQ3'  
w'VuC82SZ  
public class FileSplitterFetch extends Thread { U5@B7v
1  
\u(Gj]B#"  
E}a.qM'  
String sURL; //File URL OYn5k6  
long nStartPos; //File Snippet Start Position RL/7>YQ  
long nEndPos; //File Snippet End Position ua &uR7  
int nThreadID; //Thread's ID FeQo,a

  
boolean bDownOver = false; //Downing is over _bg Zl  
boolean bStop = false; //Stop identical j
VN=_Y}\  
FileAccessI fileAccessI = null; //File Access interface GC3d7  
Fm6]mz%~u#  
`w8cV?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException x!pd50-  
{ )1R[X!KQ7  
this.sURL = sURL; ImH9 F\  
this.nStartPos = nStart; 
0Q8iX)  
this.nEndPos = nEnd; A )CsF  
nThreadID = id; ,1lW`Krx  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '&K' 0qG  
} !W0JT#0
 
7.g,&s%q  
X}
C8!LA  
public void run() .*>C[^  
{ Z?3B1o9  
while(nStartPos < nEndPos && !bStop) m(kv:5<>  
{ R\#5;W^  
H1KXAy`&  
R[fQ$` M  
try{ K V?+9qa,  
URL url = new URL(sURL); @Gw]cm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O&~ @ior  
httpConnection.setRequestProperty("User-Agent","NetFox"); nmE H/a  
String sProperty = "bytes="+nStartPos+"-"; QQS"K g  
httpConnection.setRequestProperty("RANGE",sProperty); ^8-,S[az  
Utility.log(sProperty); f;l}Z|dok6  
{)!ua7GF0H  
9L4;#cy  
InputStream input = httpConnection.getInputStream(); U~@;2\ o  
//logResponseHead(httpConnection); >c
5  
^gpd '*b
 
qNrLM!Rj  
byte[] b = new byte[1024]; Fl{~#]  
int nRead; 7M5HvG#w%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a\Gd;C ^`  
{ ?:l:fS0:{  
nStartPos += fileAccessI.write(b,0,nRead); 5INw#1~  
//if(nThreadID == 1) 2bw.mp&v1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;'Z"CbS+  
} -4F}I3I  
xcQ^y}JN  
D(dV{^} 9  
Utility.log("Thread " + nThreadID + " is over!"); oY,{9H37b  
bDownOver = true; >qO
l1]uF  
//nPos = fileAccessI.write (b,0,nRead); f><V;D#  
} v@s"*E/PF7  
catch(Exception e){e.printStackTrace ();} Z.unCf3Q  
} Jcs /i  
} vQnhb%  
E piF$n  
k*F9&-rtN  
//打印回应的头信息 iS"6)#a72  
public void logResponseHead(HttpURLConnection con) I|c?*~7*  
{ 0QrRG$<4X  
for(int i=1;;i++) R3)ccom  
{ hjk]?MC  
String header=con.getHeaderFieldKey(i); ,kYX|8SO  
if(header!=null) bu\(KR$s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); EqI
s&){  
Utility.log(header+" : "+con.getHeaderField(header)); O~x{p,s U  
else ;<E?NBV^  
break; ]rg-=Y k  
} pI>GusXg  
} n: {f\  
<4/q5
*&  
|q\i, }  
public void splitterStop() F*Yx1vj  
{ s+G(N$0U  
bStop = true; dpt P(H  
} ZGC
p[2$  
\RFA?PuY  
/;21?o  
} &f?JtpB  
EKsOj&ZiJ  
HAs/f#zAk6  
/* 1L\r:mx3  
**FileAccess.java |N 2r?b/g  
*//文件访问(定位，写) q$}J/w(,  
package NetFox; ~=oCou`XF  
import java.io.*; Ip8:~Fl]  
@j%@Z  
$~ d6KFT  
public class FileAccessI implements Serializable{ wXBd"]G)C  
CR#-!_=4  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $,I@c"m{  
RandomAccessFile oSavedFile; n>SK2`  
long nPos; k{ZQM  
Jk{v(W#  
b#t5Dve  
public FileAccessI() throws IOException 0 EA3>$;  
{ U56g|V  
this("",0); la$%%@0/  
} ^hT2ed +  
XZ(<Mo\v  
20J-VN:  
public FileAccessI(String sName,long nPos) throws IOException ']OT7)_
 
{ { W5 _KX  
oSavedFile = new RandomAccessFile(sName,"rw"); RgM=g8}M  
this.nPos = nPos; ^ ~Tn[w W_  
oSavedFile.seek(nPos); Sb)}  
} =~)rT8+)  
"#f5jH  
9c{ ~$zJW  
public synchronized int write(byte[] b,int nStart,int nLen) uX1{K%^<TW  
{ %y)hYLOJ  
int n = -1; qpa}6JVQ+j  
try{ 2G3Hi;q18  
oSavedFile.write(b,nStart,nLen); {)Wa"|+  
n = nLen; Un5 AStG  
} }ZiJHj'<  
catch(IOException e) C!^;%VQ}d  
{ cVmF'g  
e.printStackTrace (); 8N<mV^|}  
} e?]HNy  
-Wre4^,v  
T[cJ
  
return n; "`a,/h'  
} )$*B  
vP%:\u:{  
#9qX:*>h  
} f&$$*a  
-7Kstc-  
P4E_<v[  
/* l)EtK&er(}  
**SiteInfoBean.java 4>Nig.#   
*/ : 'pK  
package NetFox; ]/[@.   
/}CAd  
*ck'vV'@  
public class SiteInfoBean { XuU>.T$]c  
.n?i'8  
D@@"w+  
private String sSiteURL; //Site's URL J10&iCr{r*  
private String sFilePath; //Saved File's Path ~BnmAv$m[  
private String sFileName; //Saved File's Name W3R43>$  
private int nSplitter; //Count of Splited Downloading File nwDGzC~y<  
$)=`Iai  
AD6 b  
public SiteInfoBean() &oFgZ.  
{//nSplitter的缺省值为5 !D/W6Ic@  
//default value of nSplitter is 5 9'ky2 ]w  
this("","","",5); _skE\7&>X  
} 7Q&S [])  
f67pvyy -  
%PK(Z*>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J DOs.w  
{ 4#ifm#  
sSiteURL= sURL; eX0[C0#  
sFilePath = sPath; <LX-},?P  
sFileName = sName; d%p{l)Hd  
this.nSplitter = nSpiltter; Y"m}=\4{  
$:v
S_#  
98UI]? 4  
} +NOq>kH@  
4:kDBV;v  
}5B\:*yW  
public String getSSiteURL() koj*3@\p/  
{ gf/<sH2}  
return sSiteURL; @?t+O'&  
} K>-01AGHL  
8N`Rf;BM  
(!Fu5m=<8  
public void setSSiteURL(String value) ~P*{%=a  
{ Ve40H6Ox  
sSiteURL = value; ]2iEi`"[  
} SxX  
;g<y{o"Q3p  
OgCNqW d-  
public String getSFilePath() bhfC2@  
{ '\"5qB  
return sFilePath; 81)i>]  
} @U =~c9  
gaE8\JSr  
=}SLQdT  
public void setSFilePath(String value) J@ 8OU  
{ g}*p(Tp9:  
sFilePath = value; )k4&S{=  
} ~!/agLwY  
uME_/S uO  
Z07n>|WF-  
public String getSFileName() LvL2[xh%&  
{ (:}}p}u  
return sFileName; X0LC:0+  
} Yv"B-oy  
NK%Ok  
,lb}&uZo  
public void setSFileName(String value) ]Z[0xs  
{ !H6X%hlk  
sFileName = value; bj?=\u  
} )X8N|W>vh  
|jcIn[)=  
V&lx0Dy  
public int getNSplitter()
mRC   
{ V2'5doo  
return nSplitter; hXD/
  
} 6E_YUk?KW  
<s'0<e!./t  
65rf=*kz:  
public void setNSplitter(int nCount) Mh@
n>+IR  
{ LeNSjxB  
nSplitter = nCount; s Dsq:z  
} 7{NH;U t  
} C879eeJ  
@r\{iSg&g.  
Nema>T]  
/* G"Hj$  
**Utility.java :_o^oi7G  
*/ oZ
i{v]4  
package NetFox; ##OCfCW  
Qp>Z&LvC5  
D|'[[=  
public class Utility { ,z>w^_  
BUyKiMW49  
mR8tW"Z2  
public Utility() yI%q3lB}^  
{ /.sho\a  
&{ZUY3  
4Wa*Pcj  
} y'O<*~C(X  
1r3} V7  
//线程睡眠 v
XG?8Q  
public static void sleep(int nSecond) Xu|2@?l9  
{ *dsI>4%m  
try{ XaMsIyhI  
Thread.sleep(nSecond); SUjo%3R  
} !mUO/6Q hq  
catch(Exception e) 4AKPS&k;  
{ <@Y`RqV+  
e.printStackTrace (); eAG)+b  
} f5/s+H!  
} as[! 9tB]
 
p+b$jKWQ  
//日志 Hk=HO|&<XB  
public static void log(String sMsg) r4
b-.>w  
{ S7~HBgS<  
System.err.println(sMsg); g~76c.u-  
} j@{dsS:6  
.-Dc%ap
]  
al7D3J  
public static void log(int sMsg) $ k_6  
{ @\W-=YKLg  
System.err.println(sMsg); NnaO!QW%  
} bc>&Qj2Z7c  
} xT!<x({  
QH?sx k2  
QuC_sFP10  
/* _7dp(R  
**TestMethod.java ,,lR\!>8  
*/ 5gb:,+  
package NetFox; uJ0Wb$%  
}^^c/w_  
pX1Us+%  
public class TestMethod { S27s Rxfr  
zU_dk'&,  
 {@k , e  
public TestMethod() > }kZXeR|  
{ ///xx/weblogic60b2_win.exe 3jHg9M23[^  
try{ .bj:tmz  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); dqO]2d  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =r3g:j/>q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =y`-:j\  
fileFetch.start(); 6;;2e> e  
} l+X
\>,  
catch(Exception e){e.printStackTrace ();} d ,.=9
  
]EG8+K6  
A8Km8"  
} 4vCUVo r  
XWq"_$&LF  
d1'= \PYr  
public static void main(String[] args) 5hTScnL%  
{ `7[!bCl  
new TestMethod(); $9:  @M.  
} ^)C#  
} 7z
Ifsb  
点击下载更多相关资料