http断点续传简单实现（java)

/* +2w<V0V_  
**SiteFileFetch.java -"EPU]q  
*/ vdh[%T,&  
package NetFox; V4&a+MJ@  
import java.io.*; =zTpDL  
import java.net.*; 6rM{r>  
mQ9y{}t=4  
LrT? ]o  
public class SiteFileFetch extends Thread { ZH<qidpR  
7x]q>Y8T  
-jzoGzC3  
SiteInfoBean siteInfoBean = null; //文件信息Bean u2OrH3E4E3  
long[] nStartPos; //开始位置 
26p_fKY  
long[] nEndPos; //结束位置 y@SI)&D  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ehLn+tg  
long nFileLength; //文件长度 < lUpvr  
boolean bFirst = true; //是否第一次取文件 b2H-D!YO^  
boolean bStop = false; //停止标志 X]
D:vuB  
File tmpFile; //文件下载的临时信息 a'g&1N0Rc  
DataOutputStream output; //输出到文件的输出流 @;tM R|p  
:`>tCYy;  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） CzIs_/  
public SiteFileFetch(SiteInfoBean bean) throws IOException Cj=_WWo  
{ o;21|[z  
siteInfoBean = bean; G#~U\QlG-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yg4#,4---b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1\)C;c
,  
if(tmpFile.exists ()) Res4;C  
{ Fkg%_v$  
bFirst = false; `(/xj{"Fr}  
read_nPos(); IBUFXzl  
} h;@>E:4Tg  
else @yj~5Gf(j  
{ nvA7eTO6C  
nStartPos = new long[bean.getNSplitter()]; L F&!od9[  
nEndPos = new long[bean.getNSplitter()]; 2Da0*xn{  
} [dXa
,  
BY9Z}/{j  
DXFDs=u  
r?w>x`  
}
do9~#F  
"Th;YJu  
*\B(-  
public void run() 6ma.FvSIM  
{ `(DHa=s1  
//获得文件长度 mM~&mAa+Z  
//分割文件 JmeE}:5lpj  
//实例FileSplitterFetch U5OFw+J  
//启动FileSplitterFetch线程 #M<YNuE#"  
//等待子线程返回 F'"-aB ~  
try{ i(Zz
E  
if(bFirst) HCx0'|J  
{ ~'|^|*}~Dj  
nFileLength = getFileSize(); ysC
K_  
if(nFileLength == -1) 4l>U13~#  
{ Z|fi$2k0!  
System.err.println("File Length is not known!"); 4TyzD%pOw  
} AAqfp/DC  
else if(nFileLength == -2) B%`|W@v  
{  FLZ9Rg  
System.err.println("File is not access!"); s:cJF  
} ?2R!n"m-d  
else 76]Z~^Y  
{ zl|+YjR  
for(int i=0;i<nStartPos.length;i++) Qn~{TZz  
{ $Ld-lQsL  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2 6 >9$S  
} hL&7D@  
for(int i=0;i<nEndPos.length-1;i++) Vk*XiEfKm>  
{ }{kn/m/  
nEndPos = nStartPos[i+1]; :S}ZF$ $j%  
} /0!.u[t)~  
nEndPos[nEndPos.length-1] = nFileLength; zqURnsJ  
} ';}:*nZ//_  
} 'n^?DPvD  
 w%::
~]  
Spu;  
//启动子线程 l8:!{I?s=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -x:7K\=$SX  
for(int i=0;i<nStartPos.length;i++) e z_c;  
{ KS1udH^Zc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }@/Ox  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {U@"]{3Qx  
nStartPos,nEndPos,i); K4H2
7SH  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SL/'UoYm<  
fileSplitterFetch.start(); _00}O+GLM4  
} 2^"!p;WQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0LYf0^P  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -ik=P]?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", bKsEXS  
nEndPos = " + nFileLength); 4^k8|#c  
// fileSplitterFetch[nPos.length-1].start(); D=Nt0y  
4F6I7lu  
dcTZL$  
//等待子线程结束 &x=_n'  
//int count = 0; XH0o8\.  
//是否结束while循环 _|4QrZ$n(  
boolean breakWhile = false; }'86hnW  
*3OlWnZ?  
}eI9me@Aa  
while(!bStop) 
C3N1t  
{ U>00B|<GJ  
write_nPos(); /?0|hi<_$  
Utility.sleep(500); M,yxPHlN  
breakWhile = true; =v!Z8zk=W  
8kr$w$=q  
XiV K4sD8  
for(int i=0;i<nStartPos.length;i++) DZLEx{cm  
{ ?R4u>AHS@  
if(!fileSplitterFetch.bDownOver) ,\1Rf
.  
{ @HnahD  
breakWhile = false; osmCwM4O  
break; '66nqJb*  
} pHye8v4fvi  
} Cs,Cb2[  
if(breakWhile)  _VM}]A  
break; XbeT x  
h,-i\8gq  
#c"05/=A  
//count++; pIug$Ke_%  
//if(count>4) H;@0L}Nu+}  
// siteStop(); *a0#PfS[  
} aIr"!. 4  
Sn 7h$  
1
{RA\CF  
System.err.println("文件下载结束！"); %KN2iNq  
} %Wm)  
catch(Exception e){e.printStackTrace ();} (Rp5g}b  
} #7sxb  
m*h O@M  
~(NFjCUY?  
//获得文件长度 1K)9fMr]  
public long getFileSize() AAuwE&Gg  
{ cVarvueS  
int nFileLength = -1; O3dQno  
try{ /UY'E<wBx  
URL url = new URL(siteInfoBean.getSSiteURL()); BT^=p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V\Y,4&bI  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0S }\ML  
4PR&67|AH_  
09 f;z  
int responseCode=httpConnection.getResponseCode(); 
MSp)Jc  
if(responseCode>=400) F x$W3FIO]  
{ YACx9K H  
processErrorCode(responseCode); blP8"(U  
return -2; //-2 represent access is error NXz/1ut%  
} JDp=w,7LF  
gxeu2HG  
nE0I[T(  
String sHeader; $GQEdVSNo  
- K"L6m|  
.b!HEi<F  
for(int i=1;;i++) ti]8_vP}*  
{ x>Dix1b:.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5p-vSWr!  
//Utility.log(in.readLine()); +# !?+'A  
sHeader=httpConnection.getHeaderFieldKey(i); usu{1&g  
if(sHeader!=null) hY
*^rY'  
{ 6Bd:R}yZP7  
if(sHeader.equals("Content-Length")) 7|[Dr@.S  
{ *_Ih@f H  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ADP3Nic  
break; <]#_&Na  
} z,@R jaX  
} VG$%Vs  
else Tc/<b2\g  
break; ycEp,V;[Z  
} :9q|
<[Y^  
} AT2D+Hi=E  
catch(IOException e){e.printStackTrace ();} xa !/.  
catch(Exception e){e.printStackTrace ();} 1-<?EOYaE  
!wKN
Ye  
jd"YaZOQ  
Utility.log(nFileLength); :;LaV  
>m=
XqtP  
v0;dk(  
return nFileLength; An,TunX  
} .Rb1%1bdc  
N>g6KgX{K  
=BV_?  
//保存下载信息（文件指针位置） s%m?Yh3  
private void write_nPos() M?n}{0E4  
{ mM+^v[=  
try{ .\)e

k[?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S3QX{5t\  
output.writeInt(nStartPos.length); B
HNJH  
for(int i=0;i<nStartPos.length;i++) {n<1uh9~$8  
{ MRK3Cey}%  
// output.writeLong(nPos); OKj\>3  
output.writeLong(fileSplitterFetch.nStartPos); *Ct ^jU7  
output.writeLong(fileSplitterFetch.nEndPos); 6pZ/C<Y|W  
} 6$csFW3R  
output.close(); X&@>M}  
} b=L|GV@$  
catch(IOException e){e.printStackTrace ();} n
^|7ycB'  
catch(Exception e){e.printStackTrace ();} uhwCC  
} [Z1,~(3  
fq)
:'E)  
O31.\ZR2  
//读取保存的下载信息（文件指针位置） )o&}i3~Q  
private void read_nPos() [W dxMU  
{ c.>OpsF  
try{ S6_dmTV*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0nR_I^  
int nCount = input.readInt(); <4;L&3  
nStartPos = new long[nCount]; 78]( ZYJV  
nEndPos = new long[nCount]; '(3|hh)Tl  
for(int i=0;i<nStartPos.length;i++) fnFIw=d  
{ 1=~##/at  
nStartPos = input.readLong(); `YBHBTG'o!  
nEndPos = input.readLong(); `#j;\  
} PBwKRD[I  
input.close(); nQfSQMg  
} ytfr'sr/  
catch(IOException e){e.printStackTrace ();} M=EV^Tw-=  
catch(Exception e){e.printStackTrace ();} Of<Vr.m{R  
} A2`Xh#o  
rC,ZRFF  
#
g1,U7vv8  
private void processErrorCode(int nErrorCode) ),-MrL8c%  
{ _M
- PF$  
System.err.println("Error Code : " + nErrorCode); i*+N[#yp  
} C}:_&^DQ  
i[vOpg]J  
Dd)L~`k{)  
//停止文件下载 o4aFgal1  
public void siteStop() O tR  
{ T{F 'Y%  
bStop = true; T@r%~z  
for(int i=0;i<nStartPos.length;i++) 5j5}c`:  
fileSplitterFetch.splitterStop(); Y}r UVn  
KM-7w66V  
/86PqKU(P  
} h]o{> |d9  
} i| *r/  
//负责部分文件的抓取 -TNb=2en(  
**FileSplitterFetch.java !Bhs8eGr3  
*/ |W|RX3D  
package NetFox; ,mt=)Ac  
[R/'hH5  
{9nH#yv  
import java.io.*; su~J:~q  
import java.net.*; v-B&"XGy:  
4ZT0~37(  
C4eQ.ep  
public class FileSplitterFetch extends Thread { 7x(z  
-Vjrh/@  
Tpp?(lT7r  
String sURL; //File URL L:UPS&)  
long nStartPos; //File Snippet Start Position Pbakw81!~  
long nEndPos; //File Snippet End Position K5\;'.9M  
int nThreadID; //Thread's ID /)XN^Jwa;m  
boolean bDownOver = false; //Downing is over n%ZOR1u)k#  
boolean bStop = false; //Stop identical wD $sKd  
FileAccessI fileAccessI = null; //File Access interface %9T|"\  
vu_ u\2d  
IoHYY:[-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -W1Apd%>  
{ ()(/9t  
this.sURL = sURL; VCvFCyAz  
this.nStartPos = nStart; #]s&[O43  
this.nEndPos = nEnd; jd}-&DN  
nThreadID = id; XchVsA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 SbD B[O%  
} Z$Vd8U;  
[d6
TwKv  
*orP{p-U  
public void run() W7q!F  
{ ""_%u'7t5I  
while(nStartPos < nEndPos && !bStop) Z WhV"]w&  
{ l9F]Lw  
T^ RYN  
rL6Y4u0e%  
try{ MtBoX*"  
URL url = new URL(sURL); RJ$x{$r[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U^9#uK6GM  
httpConnection.setRequestProperty("User-Agent","NetFox"); - ]U2G:  
String sProperty = "bytes="+nStartPos+"-"; xn2f!\%p  
httpConnection.setRequestProperty("RANGE",sProperty); l1
"*  
Utility.log(sProperty); [?VkwFD0  
q,.@<sW
 
Y|F~w~Cb  
InputStream input = httpConnection.getInputStream(); t ;bU#THM  
//logResponseHead(httpConnection); f^@DuI  
kD_616  
)t$o0!  
byte[] b = new byte[1024]; k'-5&Q  
int nRead; lQf38u||  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~_|ZUb  
{ crr#tad.  
nStartPos += fileAccessI.write(b,0,nRead); .=/TT|eMS  
//if(nThreadID == 1) >VB*Xt\C&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ew|e66Tw$  
} -zH` 9>J5|  
Ydh+iLjhx  
h0zv@,u  
Utility.log("Thread " + nThreadID + " is over!"); &&`-A6`p  
bDownOver = true; unAu8k^  
//nPos = fileAccessI.write (b,0,nRead); 0GMov]W?i  
} vQ1#Zgy  
catch(Exception e){e.printStackTrace ();} > ZKHjw  
} V})b.\"F  
} `fq#W#Pu  
'\/|K  
YG#.L}X@C  
//打印回应的头信息 Pfl8x  
public void logResponseHead(HttpURLConnection con) ?m:,hI  
{ 75*q^ui  
for(int i=1;;i++) # 4;(^`?  
{ 9=p/'d8  
String header=con.getHeaderFieldKey(i); 0z`-fQfK  
if(header!=null) V-w{~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y]:Ch (Q  
Utility.log(header+" : "+con.getHeaderField(header)); |&AZ95v   
else 9"b =W@  
break; 9{XV=a v  
} 6w4}4i  
} [F}_Ime  
[IPXU9&Q  
2#`9OLu8X  
public void splitterStop() cxn*!TwDs  
{ !9vq"J~hz"  
bStop = true; C=<PYkt,L  
} W&;,7T8@  
H.*aVb$  
,w$:=;i  
} 2rG$.cGN"  
X.J$ 5b  
I
|vfxf  
/* &W$s-qf".  
**FileAccess.java d3tr9B  
*//文件访问(定位，写) T1g3`7C3  
package NetFox; lkaWwjv_D  
import java.io.*; cX4I+Mf  
)6:1`&6  
yp"h$  
public class FileAccessI implements Serializable{ 7~m[:Eg6[s  
v)%0`%nSR  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %>!$eCX  
RandomAccessFile oSavedFile; R 9b0D>Lxt  
long nPos; u E<1PgW  
,<!v!~Iy  
Vl%UT@D|  
public FileAccessI() throws IOException (u-eL#@  
{ ]lZg }7h  
this("",0); l3HfaCP6:  
} eR>|1s%^  
V&Q_iE  
fOt?2Bh  
public FileAccessI(String sName,long nPos) throws IOException Ln"D .gpq  
{ vMeB2r<  
oSavedFile = new RandomAccessFile(sName,"rw"); ZFNg+H
/k  
this.nPos = nPos; u{%dm5  
oSavedFile.seek(nPos); BY`vs+]XY  
} B*AB@  
o3(:R0  
JXF0}T)C  
public synchronized int write(byte[] b,int nStart,int nLen) Tga%-xr+  
{ %ZM"c  
int n = -1; 1}ws@hU  
try{ -xL^UcG0  
oSavedFile.write(b,nStart,nLen); |wGmu&fY  
n = nLen; EClx+tz;`  
} \x
<i6&.  
catch(IOException e) T*jQzcm~?  
{ 6}>CP
i#  
e.printStackTrace (); )8*}-z  
} \"1%>O*  
@cu#rWiG  
\/F*JPhy  
return n; eNu]K,rT  
} c)4L3W-x=  
^"] ]rZ)  
yyM`J7]J  
} DLD5>  
$nr=4'yZ  
vC!B}~RG  
/* ^5rB/y,  
**SiteInfoBean.java _t?#
 
*/ ~'w]%rh!  
package NetFox; fxknfgbg  
UT_kw}1o  
,ut7`_Fy  
public class SiteInfoBean { kc/"  
: 22)` ;0  
QzVoU |  
private String sSiteURL; //Site's URL YT'olk  
private String sFilePath; //Saved File's Path U<I
]_]  
private String sFileName; //Saved File's Name _f"KB=A_x  
private int nSplitter; //Count of Splited Downloading File ?.^n,[2  
i'p6#  
z>z9xG'  
public SiteInfoBean() :pvB}RYD  
{//nSplitter的缺省值为5 @|D#lBm  
//default value of nSplitter is 5 {JQCfs  
this("","","",5); D-LQQ{!D5  
} ag6[Nk  
H @5dj}  
$V,ZH* g  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) m,V"S(A  
{ Q%x-BZb~  
sSiteURL= sURL; HsKq/Oyk  
sFilePath = sPath; "xAIK  
sFileName = sName; \hI|I!sDWy  
this.nSplitter = nSpiltter; 6G7+&g`  
F+)g!NQZ  
PFjh]/=  
} =HjC.h  
13fyg7^JP  
/Xl(>^|&  
public String getSSiteURL() LjCUkbzQF  
{ 7ygz52  
return sSiteURL;
^~^=$fz  
} h?p!uQ  
Cs2kbG_  
lf#5X)V  
public void setSSiteURL(String value) kQD~v+u{`  
{ z&y
VU<;  
sSiteURL = value; ('Ha$O72  
} *#83U?  
31cZ
6[  
`#4q7v~>oe  
public String getSFilePath() VUC_|=?dL  
{ /sr.MT
 
return sFilePath; yVWt%o/  
} cCs@[D#O1  
d)GR]^=r  
5E^P2Mlc  
public void setSFilePath(String value) (dwb{+HW  
{ RQU-]qQ8BM  
sFilePath = value; E+cx8(   
} 8>`8p0I$+  
Oj '^Ww m  
$B`ETI9g-N  
public String getSFileName() b9VI(s>  
{ ;?C`Jagx  
return sFileName; |lN=q44I  
} L@.Trso  
)JY#8,{w  
d2fiPI7lg  
public void setSFileName(String value) ;@qQ^!g2  
{ iUq_vQ@}}  
sFileName = value; @H}{?-XyA  
} 5Gm8U"UR  
NIHcX6Nw  
U/ax`_  
public int getNSplitter() pnUL+UYeM  
{  PZj}]d `  
return nSplitter; ']N\y6=fn9  
} 0E9 lv"3o  
,/Q`gRBh"  
hqa6aYY x  
public void setNSplitter(int nCount) <5zr|BTF]F  
{ Zt}b}Bz  
nSplitter = nCount; P|ftEF  
} &FG0v<f5Pv  
} 9Y?``QBN  
5%+epzy  
E {UhM q7  
/* .  LeS-  
**Utility.java 2 ,krVb?<  
*/ ?*6Q;.f<  
package NetFox; ni6zo~+W]  
}(oWXwFb&W  
xeKm} MN]S  
public class Utility { \H 5t-w=  
8%p+:6kP5  
),H1z`c&I  
public Utility() E
:;MI{;7  
{ 5=V29  
SNf~%B?`L  
yq!peFu  
} Y=,9M  
Gn4XVzB`O  
//线程睡眠 b>]UNf"-  
public static void sleep(int nSecond) tMXNi
\Bj  
{ ?;A\>sP  
try{ GK1P7Qy?V  
Thread.sleep(nSecond); =i6k[rg  
} OS1f}<  
catch(Exception e) _-2;!L#/  
{ j+e s  
e.printStackTrace (); NTSIClm}U
 
} ExF6y#Y G<  
} h@J3+u<  
nELY(z  
//日志 BU|)lU5)z  
public static void log(String sMsg) UG4I@@=  
{ IFW7MF9V  
System.err.println(sMsg); '<'5BeU  
} b5?kgY  
ru|*xNXKgC  
h-
x~:$Z,  
public static void log(int sMsg) x4,[5N"}YK  
{ \+&)9 !K  
System.err.println(sMsg); Pa"Kk9!o36  
} Yp\Y]pym  
} ?1r<`o3l\  
j%}9tM6[  
M"-.D;sa1  
/* f1XM_  
**TestMethod.java )u0/s'  
*/ 4UND;I&  
package NetFox; [;UI8Stw  
GNSh`Tm=#  
2`A[<S  
public class TestMethod { RL H!f1cta  
\jZ)r>US"  
F+L%Ho;@P  
public TestMethod() o_5[}d  
{ ///xx/weblogic60b2_win.exe CWJ
N{  
try{ dp4vybJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); GL,[32~C  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :B\$7+$v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); N^AlhR^  
fileFetch.start(); TX7dwmt)N  
} HVzkS|^F  
catch(Exception e){e.printStackTrace ();} /82E[P"}6R  
:Ys ;)W+R  
ux,eY  
} JB=L{P J  
43<i3O  
|?hsMN  
public static void main(String[] args) 4n1 g@A=y  
{ t;u)_C,bmP  
new TestMethod(); N8=-=]0G  
} aOQT-C[ O  
} keStK8  
点击下载更多相关资料