http断点续传简单实现（java)

/* w=@Dv  
**SiteFileFetch.java Vz[C=_m  
*/ U<-D(J
  
package NetFox; CH/rp4NeSy  
import java.io.*; ^W@5TkkBQq  
import java.net.*; 8$|=P!7EO  
)CyS#j#=  
F&Hrk|a  
public class SiteFileFetch extends Thread { F<w/PMb  
RT5T1K08I  
MY/}-*|  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3N:D6
w-R  
long[] nStartPos; //开始位置 ::F|8  
long[] nEndPos; //结束位置 Np)lI
GE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :i7;w%
B  
long nFileLength; //文件长度 =qIyqbXz  
boolean bFirst = true; //是否第一次取文件 )_NO4`ejs/  
boolean bStop = false; //停止标志 Q7A MRrN  
File tmpFile; //文件下载的临时信息 Vq2$'lY  
DataOutputStream output; //输出到文件的输出流 ;=UsAB]  
WjjB<YKzF  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {_dvx*M  
public SiteFileFetch(SiteInfoBean bean) throws IOException %K QQ,{ b  
{ d5l UGRg  
siteInfoBean = bean; 4`R(?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RrgGEx  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .[ mRM  
if(tmpFile.exists ()) *9i{,I@  
{ |WUG}G")*x  
bFirst = false; s9d_GhT%-  
read_nPos(); 4Xv*wB1  
} uwBiW  
else IIqUZJ  
{ &"q=5e2  
nStartPos = new long[bean.getNSplitter()]; Q5_o/wk  
nEndPos = new long[bean.getNSplitter()]; o`RKXfCq  
} o? $.fhD   
fxIf|9Qi`  
{zFMmPid  
snikn&  
} 7[wieYj{  
yCX?!E;La  
,v&(YOd  
public void run() 4Z,!zFS$`  
{ _-Fs#f8  
//获得文件长度  f V(J|  
//分割文件 x3krbUlx  
//实例FileSplitterFetch cs'{5!i]  
//启动FileSplitterFetch线程 wa3}SB  
//等待子线程返回 OUXR  
try{  rXU\  
if(bFirst) +t;7tQDVB  
{ Xs?o{]Fe  
nFileLength = getFileSize(); "wHFN>5B  
if(nFileLength == -1) ~3 bPIg7D  
{ E+JqWR5  
System.err.println("File Length is not known!"); :/Qq@]O>  
} ]$_NyAoBb  
else if(nFileLength == -2) kSh( u  
{ '`<w#z}AF  
System.err.println("File is not access!"); !v0LBe4  
} >dG[G>  
else N
.{D$"  
{ 6MkP |vr6  
for(int i=0;i<nStartPos.length;i++) ;w[0t}dPl  
{
OydwE  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #C3.Jef  
} -D$8  
for(int i=0;i<nEndPos.length-1;i++) m9Hit8f@Q  
{ i7>tU=  
nEndPos = nStartPos[i+1]; r0gJpttDl  
} ?K\axf>F  
nEndPos[nEndPos.length-1] = nFileLength;
@y&bw9\  
} t<viX's  
} VU d\QR-  
W#sU`T   
"FKOaQ%IH  
//启动子线程 #N cK X  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b>N8F^}~O  
for(int i=0;i<nStartPos.length;i++) uRr o?m<  
{ z]9MM 2+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |H+Wed|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), k)Qtfj}uij  
nStartPos,nEndPos,i); 680o)hh4m>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :Zz '1C  
fileSplitterFetch.start(); N*&1GT#9  
} xK\
d4"  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e@OX_t_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); iW /}#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^]-6u:J!  
nEndPos = " + nFileLength); Q)[C?obd v  
// fileSplitterFetch[nPos.length-1].start(); {,~3.5u   
6f*CvW  
igR";OQk  
//等待子线程结束 w)Qp?k d  
//int count = 0; j^2wb+`  
//是否结束while循环 /
RC7"QzL  
boolean breakWhile = false; >&5DsV.B  
q#=(e:aCb  
5N&?KA-  
while(!bStop) J~UuS+Ufv  
{ s}% M4  
write_nPos(); P}7'm M  
Utility.sleep(500); W1=H8O  
breakWhile = true; p"ZG%Ow5Q]  
P(z++A&  
1HZO9cXJ  
for(int i=0;i<nStartPos.length;i++) n#OB%@]<V  
{ s+?zL~t  
if(!fileSplitterFetch.bDownOver) ?m?::R
H  
{ r|Tcfk]%  
breakWhile = false; ={wcfhUl+  
break; 8eHyL  
} uGEfIy 2  
} }d}Ke_Q0  
if(breakWhile) exUu7&*:  
break; xjj6WED  
?oHpFlj  
u($!z^h  
//count++; R',rsGd`6j  
//if(count>4) d,n 'n  
// siteStop(); &@Be2!%'9K  
} Y\?"WGL)p  
sI^Xb@'09$  
K}MK<2vU  
System.err.println("文件下载结束！"); <;Zmjeb+#  
} (rm?jDm   
catch(Exception e){e.printStackTrace ();} I75DUJqy]  
} &AbNWtCV+G  
-0x #  
\Et3|Iv  
//获得文件长度 oHn Ky[1  
public long getFileSize() =.]4;z  
{ SmSH2m-  
int nFileLength = -1; e [mm  
try{ 6.nCV0xA  
URL url = new URL(siteInfoBean.getSSiteURL()); FSW_<%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <+vw@M  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;P%1j|7  
_C[q4?  
~<F8ug#  
int responseCode=httpConnection.getResponseCode(); 9H`XeQ.  
if(responseCode>=400) |_aa&v~  
{ GH:jH]u!V  
processErrorCode(responseCode); {go;C}  
return -2; //-2 represent access is error '^~{@~ ;%L  
} 65$+{s  
nwRc%C``UK  
MJ [m  
String sHeader; "Nbq#w\  
41?HY{&2  
/zVOK4BqN+  
for(int i=1;;i++) 
Oso#+  
{ *@=/qkaJaI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~^fZx5  
//Utility.log(in.readLine()); l$pm_%@2]  
sHeader=httpConnection.getHeaderFieldKey(i); G[I"8iS,  
if(sHeader!=null) JL}_72gs  
{ co|aC!7  
if(sHeader.equals("Content-Length")) Y;^l%ePuW  
{ ZyPVy  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .Una+Z  
break; ARwD~Tr  
} HjD8u`qQ  
} hxd`OG<gF  
else 94.DHZqh  
break; a:IC)]j$_  
} EF}\brD1  
} r8rgY42  
catch(IOException e){e.printStackTrace ();} J({Xg?  
catch(Exception e){e.printStackTrace ();} vJc-6EO
 
-23w2Qt  
>T3-  
Utility.log(nFileLength); :L@?2),  
l=)x
o@6  
n QZwC  
return nFileLength; ,I(d6  
} /quc}"__  
gANuBWh8T  
Rmt~,cW!\  
//保存下载信息（文件指针位置） ][h%UrV  
private void write_nPos() ]]9R mh=  
{ <~'"<HwtK  
try{ vB|hZTW  
output = new DataOutputStream(new FileOutputStream(tmpFile)); aPfO$b:  
output.writeInt(nStartPos.length); suiS&$-E  
for(int i=0;i<nStartPos.length;i++) A,hJIe  
{ sF?TmBQ*  
// output.writeLong(nPos); udUyh%n  
output.writeLong(fileSplitterFetch.nStartPos); pVw}g@<M  
output.writeLong(fileSplitterFetch.nEndPos); )SRefW.v  
} QP8Ei
~  
output.close(); ujq=F  
} 9gEw
h<  
catch(IOException e){e.printStackTrace ();} ?;+1)>{  
catch(Exception e){e.printStackTrace ();} )E@.!Ut4o  
} "ZoRZ'i  
z] PS
pUd  
}mq6]ZrK  
//读取保存的下载信息（文件指针位置） dIa+K?INX  
private void read_nPos() xU>WEm2  
{ RD'Q :W  
try{ ex9g?*Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #9}D4i.`}  
int nCount = input.readInt(); (%e.:W${  
nStartPos = new long[nCount]; pW@Pt 3u  
nEndPos = new long[nCount]; wb5baY9  
for(int i=0;i<nStartPos.length;i++) tip+q d  
{ ,+vy,<e&  
nStartPos = input.readLong(); R_ ,UMt  
nEndPos = input.readLong(); 2U\u4NO{  
} K'Tm_"[u  
input.close(); ," Wr"  
} Z/;(fL  
catch(IOException e){e.printStackTrace ();} >WQMqQ^t@  
catch(Exception e){e.printStackTrace ();} NI}yVV  
} st3l2Q  
wh\}d4gN  
Ng>5?F^v  
private void processErrorCode(int nErrorCode) YY((V@|K  
{ 7BjJhs  
System.err.println("Error Code : " + nErrorCode); (Hz^)5(~  
} ZaDyg"Tw+  
# 448-8x  
C]eSizS.  
//停止文件下载 4Lh!8g=/  
public void siteStop() [.8BTj1%  
{ %C'?@,7C  
bStop = true; YpZ+n*&+  
for(int i=0;i<nStartPos.length;i++) W5lR0)~#*  
fileSplitterFetch.splitterStop(); H*QIB_  
zyc"]IzOU  
c~$)UND^  
} o]` *M|  
} djQH1^(IU  
//负责部分文件的抓取 4(~L#}:r!  
**FileSplitterFetch.java 8'.Hyy@;  
*/ ?'#` nx(!  
package NetFox; 7he,?T)vD  
V!ZC(  
Lh"<XYY  
import java.io.*; D>@I+4{p  
import java.net.*; be{H$9'
 
3n1;G8Nf  
]Svt`0|}  
public class FileSplitterFetch extends Thread { 1N^[.=  
z8~NZ;A  
#`iB`|  
String sURL; //File URL +p_CN*10H  
long nStartPos; //File Snippet Start Position I^]2K0+x x  
long nEndPos; //File Snippet End Position yw[g!W  
int nThreadID; //Thread's ID NP#w+Qw  
boolean bDownOver = false; //Downing is over /k6MzFoid  
boolean bStop = false; //Stop identical *{@Nq=fE  
FileAccessI fileAccessI = null; //File Access interface P*Uwg&Qz)  
OwUhdiG  
5\sd3<:+  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +L|?~p`
V  
{ /y#f3r+*2  
this.sURL = sURL; [f-?ymmT  
this.nStartPos = nStart; mpEK (p  
this.nEndPos = nEnd; Sh~dwxp*"
 
nThreadID = id; }6}l7x  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 r CHl?J  
} JEwa
&  
-M~:lK]n  
OU(8V^.  
public void run() s1$nvTzBr  
{ u+e{Mim  
while(nStartPos < nEndPos && !bStop) Uq,^Wy  
{ v ~?qz5:K~  
>,Ci?[pf  

nQtWvT  
try{ uR4z&y  
URL url = new URL(sURL); &yTqZ*Yuk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p* (JjH  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9y8&9<#  
String sProperty = "bytes="+nStartPos+"-"; S6M}WR^,  
httpConnection.setRequestProperty("RANGE",sProperty); +nhLIO{{L  
Utility.log(sProperty); Mj?`j_X  
4qbBc1,7y  
E *6Cw l  
InputStream input = httpConnection.getInputStream(); R)(T^V`{  
//logResponseHead(httpConnection); :WS@=sZN  
B=T'5&  
=/+-<px  
byte[] b = new byte[1024]; j'<<4.(  
int nRead; gHEu/8E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f:,DWw`B  
{ )0W{]2  
nStartPos += fileAccessI.write(b,0,nRead); l0w]`EE  
//if(nThreadID == 1) L>NL:68yN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |A9F\A->4  
} x8\?}UnB  
5iw<>9X*  
fLD,5SN  
Utility.log("Thread " + nThreadID + " is over!"); ~i{(<.he  
bDownOver = true;  c(E{6g?  
//nPos = fileAccessI.write (b,0,nRead); v2\FA(BPn  
} )Y0!~# `  
catch(Exception e){e.printStackTrace ();} f=Gg9bnm3  
} &|ex`nwc0  
} y0.'?6k  
9C9oUtS  
,vawzq[oSy  
//打印回应的头信息 0[# 3;a  
public void logResponseHead(HttpURLConnection con) a=1@*ID  
{ NC`aP0S  
for(int i=1;;i++) nFe<w  
{ q=m'^ ,gPS  
String header=con.getHeaderFieldKey(i); aQcleTb  
if(header!=null) $am$EU?s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Xp% v.M  
Utility.log(header+" : "+con.getHeaderField(header)); wqs?828x  
else Hqx-~hQO  
break; mzKiO_g}  
} hJ? O],4J  
} 
9(7-{,c  
_p/UsJ  
aEWWP]  
public void splitterStop() 1Z2HUzqh.  
{ t+G#{n  
bStop = true; A#<?4&  
} V>LwqS~`  
.},'~NM]  
yNo0ubY  
} *W1dG#Np}  
~?Pw& K2  
6OIte-c  
/* eA?RK.e  
**FileAccess.java fu ,}1Mq#  
*//文件访问(定位，写) qkY:3O
zw  
package NetFox; :#ik. D  
import java.io.*; nEy&>z  
,HV(l+k {|  
RJ&RTo  
public class FileAccessI implements Serializable{ xn(kKB.  
At>DjKx]O  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vWv"  
RandomAccessFile oSavedFile; T2W eE@o  
long nPos; g2ixx+`?|:  
,Vm < rK  
hH3RP{'=  
public FileAccessI() throws IOException {9pZ)tB  
{ L}b.ulkMD  
this("",0); UHkMn  
} ! E5HN :#  
Vwf$JdK%&l  
3M7/?TMw{6  
public FileAccessI(String sName,long nPos) throws IOException H@>
` F  
{ P>D)7V9Hh  
oSavedFile = new RandomAccessFile(sName,"rw"); mdDOvm:&  
this.nPos = nPos; Sy_G,+$\  
oSavedFile.seek(nPos);  'KL0@l  
} v$v-2y'%  
-f^tE,
-  
6l x>>J!H  
public synchronized int write(byte[] b,int nStart,int nLen) eJ-xsH*8  
{ p)-^;=<B3  
int n = -1; ,^< R{{{-A  
try{ ED( Sg  
oSavedFile.write(b,nStart,nLen); 4l'fCZhA}  
n = nLen; +GN(Ug'R  
} ]Q1yNtN  
catch(IOException e) _6hQ %hv8  
{ ;`{H!w[D  
e.printStackTrace (); 'GWN~5  
} |aS.a&vwR  
b. '-?Nn  
P3=G1=47U  
return n; MJO-q $)c  
} ksUcx4;a@F  
-d/ =5yxL  
JFmC\  
} yx[/|nZDC4  

7xlkZF  
Mb}QD~=M  
/* 8kIks
y  
**SiteInfoBean.java 1R%.p7@5QU  
*/ ML 9' |  
package NetFox; )2o?#8J  
O8r|8]
o  

pah'>dAL  
public class SiteInfoBean { t!l&iVWs  
 |>^JRx  
SKN`2hD  
private String sSiteURL; //Site's URL /36:ms A  
private String sFilePath; //Saved File's Path G~a ZJ,  
private String sFileName; //Saved File's Name {}przrU^c  
private int nSplitter; //Count of Splited Downloading File &Z@o Q
 
RbnVL$c  
N>`Aw^ _@&  
public SiteInfoBean() +Kc
  
{//nSplitter的缺省值为5 vh%B[brUJ  
//default value of nSplitter is 5 nR~@#P\  
this("","","",5); T?
0eVvM  
} BDDlQci38  
O0v}43J[  
F/{!tx  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) b8t7u  
{ Sz`,X0a  
sSiteURL= sURL; RtS+<^2a;  
sFilePath = sPath; ? OM!+O  
sFileName = sName; 1CZgb  
this.nSplitter = nSpiltter; <'oQ \eB  
Wn2NMXK  
^^$s%{ep"  
} hn@08t G  
U7F!Z( 9  
B9z?mt'|r)  
public String getSSiteURL() JH9J5%sp  
{ LH% F8  
return sSiteURL; vvMT}-!  
} CAhXQ7w'Z  
r l%  
7JH6A'&  
public void setSSiteURL(String value) wwZ,;\  
{ $s:aW^k  
sSiteURL = value; \M^bD4';>  
} Qw*|qGvy^  
C&%_a~  
f$$/H>MJ  
public String getSFilePath() "KpGlY?^  
{ H7n>Vx:L-  
return sFilePath; 0{D'n@veP  
} va@Lz&sAE%  
k4J+J.|  
!F$6-0%  
public void setSFilePath(String value) oG\Vxg*  
{ SqpaFWr  
sFilePath = value; 
=:pJ  
} 8nV+e~-w  
bY:x8fl  
XRi8Gpg  
public String getSFileName() Q197mN+0  
{ 73;GW4,  
return sFileName; CD~.z7,LC  
} 7?_CcRe  
L="}ErmK  
$U~]=.n  
public void setSFileName(String value) )Aqtew+A&  
{ h2R::/2.  
sFileName = value; 7{*>agQh  
} gM:".Ee  
(\x]YMLH  
wIt}dc  
public int getNSplitter() Fx.=#bVX7  
{ #_p\Ie*rd  
return nSplitter; sO@Tf\d  
} UaeXY+O  
NBGH_6DROw  
e\L8oOk#r  
public void setNSplitter(int nCount) z Iu'[U  
{ )SGq[B6@I  
nSplitter = nCount;
x%B/  
} rx|pOz,:  
} 4kx N<]  
9yP;@y*d  
'H;*W|:-]  
/* evmeqQG=  
**Utility.java Avb\{)s+  
*/ '`Hr}  
package NetFox; x.$FNt(9  
<LiPEo.R  
#ABZ&Z  
public class Utility { tR$NRMZ.  
P&Vv/D  
j8sH|{H!Nq  
public Utility() 8":Q)9;%  
{ O=7CMbS3  
|sE'XT4ag  
WpvhTX  
} 3JR+O<3D  
S f# R0SA  
//线程睡眠 9->if/r,o  
public static void sleep(int nSecond) t?FBG4  
{ R:qW;n%AF  
try{ H Pz+Dm  
Thread.sleep(nSecond); (E1~H0^  
} |FRg\#kf%  
catch(Exception e) [nq@mc~<  
{ v]UwJz3<  
e.printStackTrace (); /)O"l@ }U  
} ~k5W@`"W  
} a%0EiU  
QMm%@zH  
//日志 [$UI8tV  
public static void log(String sMsg) t]G:L}AOl  
{ X:{!n({r=  
System.err.println(sMsg); @H8EWTZ  
} seJ^s@H5l  
{'H(g[k  
:ShT|n7  
public static void log(int sMsg) jPkn[W# 6  
{ aN3;`~{9  
System.err.println(sMsg); 
e\/w'  
} J'r^/  
} GQ ;;bcj&  
jebx40TA3  
lyhiFkO iH  
/* "m>81-0  
**TestMethod.java Vxt+]5X  
*/ BZ^}J!Q'*  
package NetFox; oXgcc*j  
)+Pus~w  
BMf@M  
public class TestMethod { N'=gep0
V@  
fc>L K7M  
7G],T++N  
public TestMethod() klhtKp_p  
{ ///xx/weblogic60b2_win.exe 2Tppcj v  
try{ [2cD:JL  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \fe]c :  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); q5S9C%b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); dAj$1Ke  
fileFetch.start(); ]]yO1x$Kk  
} I%Z  
catch(Exception e){e.printStackTrace ();} 3Zh)]^  
&)<)^.@3G^  
sDV Q#}a  
} V(*
(F7+  
cB&:z)i4  
zbPqYhJzA  
public static void main(String[] args) RD&PDXT4  
{ Z3!`J&  
new TestMethod(); apxph2yvS  
} u]@['7  
} wz8yD8M  
点击下载更多相关资料