http断点续传简单实现（java)

/* . r`[  
**SiteFileFetch.java eP= j.$  
*/ tcOnM w  
package NetFox; 4_Y!elH)  
import java.io.*; &t6Tcy  
import java.net.*; %6i=lyH-  
`~nCbUUee  
=]b9X7}  
public class SiteFileFetch extends Thread { gZ`DT  
`bqz
g  
7$_ :sJ  
SiteInfoBean siteInfoBean = null; //文件信息Bean 7I3:u+  
long[] nStartPos; //开始位置 Jck"Ks  
long[] nEndPos; //结束位置 kl<g;3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ) ,Npv3(  
long nFileLength; //文件长度 ?Aw3lH#:  
boolean bFirst = true; //是否第一次取文件 Qlh?
iA  
boolean bStop = false; //停止标志 $G3@< BIN  
File tmpFile; //文件下载的临时信息 f3n~{a,[  
DataOutputStream output; //输出到文件的输出流 u[EK#%  
_FsB6 G]mc  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） EfKntrom[  
public SiteFileFetch(SiteInfoBean bean) throws IOException j^I!6j=ZX  
{ +-ewE-:|L  
siteInfoBean = bean; z!Hx @){|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8ds}+TtbY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )X%oXc&C|  
if(tmpFile.exists ()) P` ]ps?l  
{ fIkT"?  
bFirst = false; 3EOyq^I%  
read_nPos(); }]GbUC!Zb  
} J6auUm` `  
else 4J}3,+  
{ L[.<o{  
nStartPos = new long[bean.getNSplitter()]; rr )/`Kmv%  
nEndPos = new long[bean.getNSplitter()]; u){S$</  
} ~U%j{8uH  
O
G}KqG!n  
?O7iK<5N  
@_Sp3nWdu  
} ^ZVOql&  
~`[8"YUL  
vJThU$s-  
public void run() ?*+1~m>  
{ 7@a\*|K6  
//获得文件长度 Wr#~GFg  
//分割文件 ?(Bl~?zD  
//实例FileSplitterFetch eJaUmK:  
//启动FileSplitterFetch线程 !Bj^i cR  
//等待子线程返回 y@ .b 4  
try{ d?}hCo=/Xq  
if(bFirst) ]bu9-X&T&  
{ JMePI%#8  
nFileLength = getFileSize(); z Lw(@&  
if(nFileLength == -1) 8!4[#y<  
{ u\3ZI
b  
System.err.println("File Length is not known!"); pN+I]NgQ  
} _yJ|`g]U3  
else if(nFileLength == -2) Ql8^]gbp+  
{ %omu
 
System.err.println("File is not access!"); |D+p$
^L  
} AysL-sqR  
else R8ZD#,;  
{ U!NI_uk  
for(int i=0;i<nStartPos.length;i++) kQ[Jo%YT?E  
{ |Eu*P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &Ea"hd  
} W
L/5 oj  
for(int i=0;i<nEndPos.length-1;i++) R#LGFXUj  
{ i'iO H|s  
nEndPos = nStartPos[i+1]; nF|Oy0  
} 4+I 3+a"  
nEndPos[nEndPos.length-1] = nFileLength; C[0MA ,^  
} ogp{rY  
} xD^wTtT  
pJ6Jx(  
Rdj8*f  
//启动子线程 )r#,ML  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; hpas'H>J  
for(int i=0;i<nStartPos.length;i++) J@gm@ jLc  
{ K4Y'B o4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $E@ouX?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), jJ<;2e~OW  
nStartPos,nEndPos,i); (gDQ\t@3-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *?p ^6vO  
fileSplitterFetch.start(); $r):d  
} Lz?*B$h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bw020@O*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7?,7TR2Ny  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Nuo^+z E  
nEndPos = " + nFileLength); ~W3:xnBEk  
// fileSplitterFetch[nPos.length-1].start(); ;/R kMS  
_hWuAJ9Qy  

0W_mCV  
//等待子线程结束 X*)?LxTj  
//int count = 0; '9"%@AFxZ  
//是否结束while循环 {=qEBbM  
boolean breakWhile = false; [bsXF#  
wePI*."]  
fw:7U%MGv  
while(!bStop) |SxMN%M
!  
{ %fBP:5%K  
write_nPos(); 4?v$<=#21*  
Utility.sleep(500); r:73uRk  
breakWhile = true; G LoiH#R  
{wHvE4F2  
2+o!o  
for(int i=0;i<nStartPos.length;i++) ^glX1 )  
{ {N"*olx  
if(!fileSplitterFetch.bDownOver) 7MoR9,(  
{ z>7=k`x`:  
breakWhile = false; }'v{dK  
break; %uj[`  
} .(JE-upJ"  
} hRa\1Jt>a  
if(breakWhile) *^uGvJXF  
break; :Jm!=U%'Z  
3Fgz)*Gu]  
?P%|P  
//count++; %n4@[fG%K  
//if(count>4) +;YE)~R?  
// siteStop(); vUqe.?5  
} 4Q@\h=r  
b'&LBT7  
nT#37v  
System.err.println("文件下载结束！"); &yB%QX{3  
} =,O/,2)  
catch(Exception e){e.printStackTrace ();} )dqR<)  
} 7:z>+AM[r  
' 4,y  
hN[X 1*  
//获得文件长度 *B%y`cj|  
public long getFileSize() zf`5>h|  
{ -Sx0qi'%  
int nFileLength = -1; aXX,Zu^  
try{ 4{Q$!O>  
URL url = new URL(siteInfoBean.getSSiteURL()); 1k$2LQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eU`
;L[  
httpConnection.setRequestProperty("User-Agent","NetFox"); F|6 nwvgq  
";756'>  
0T(O'v}.  
int responseCode=httpConnection.getResponseCode(); E1#H{
)G  
if(responseCode>=400) 0h^uOA; c  
{ N`f!D>b:dn  
processErrorCode(responseCode); Rq"VB.ef&{  
return -2; //-2 represent access is error dJloH)uJZ>  
} 04P.p6  
 c^rC8E  
y:~eU
 
String sHeader; ,|6Y\
L  
S>.q5  
UV
z=QEuYb  
for(int i=1;;i++) =sxkrih  
{ J0&zb'1  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Tc9&mKVE%(  
//Utility.log(in.readLine()); ,?Ok[G!cm  
sHeader=httpConnection.getHeaderFieldKey(i); TFNUv<>X  
if(sHeader!=null) j[_t6Z  
{ )uANmThOz  
if(sHeader.equals("Content-Length")) _MGNKA6JI  
{ ;9}w|!/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));  o1 jk=  
break; ,<7"K&  
} <_=JMA5  
} G}182"#4  
else C\y[&egww  
break; 2=jd;2~  
} ~azF+}x90N  
} eH ;Wfs2f  
catch(IOException e){e.printStackTrace ();} o^8*aH)I>Y  
catch(Exception e){e.printStackTrace ();} 4 U3C~J  
Tw2Xe S  
=g/4{IL%  
Utility.log(nFileLength); :8](&B68gE  
@m5O{[euj<  
(}9cD^F0n  
return nFileLength; $$k7_rs  
} r5D jCV"  
<9=zP/Q  
X'YfjbGo  
//保存下载信息（文件指针位置） qsD?dHi7  
private void write_nPos() !>CE(;E>z  
{ V+Y|4Y&  
try{ R 4DM_u  
output = new DataOutputStream(new FileOutputStream(tmpFile)); XPar_8I  
output.writeInt(nStartPos.length); d^ 2u}^kG  
for(int i=0;i<nStartPos.length;i++) sGXp}{E9  
{ f1)HHUB  
// output.writeLong(nPos); W/#KX}4  
output.writeLong(fileSplitterFetch.nStartPos); Kl4isGcr]  
output.writeLong(fileSplitterFetch.nEndPos); 7h(HG?2Y  
} ) ~ l\  
output.close(); VI(RT-S6  
} i6-wf Gs;  
catch(IOException e){e.printStackTrace ();} >L#];|  
catch(Exception e){e.printStackTrace ();} 3
%z  
} b\kN_  
h=uiC&B  
Is4%}J!8  
//读取保存的下载信息（文件指针位置） :Tlf4y:/w  
private void read_nPos() *>EI2HX  
{ 8dV.nO  
try{ l\q*%'Pe  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); s@[C&v  
int nCount = input.readInt(); |Dl*w/n  
nStartPos = new long[nCount]; }@3Ud' Y  
nEndPos = new long[nCount]; w%>aR_G  
for(int i=0;i<nStartPos.length;i++) 5x:Ift *  
{ MDMtOfe|  
nStartPos = input.readLong(); j)g_*\tQ  
nEndPos = input.readLong(); i58ZV`Rk`  
} 5W*7qD
[m  
input.close(); O<}ep)mr  
} }wvwZ`5t  
catch(IOException e){e.printStackTrace ();} hubfK~  
catch(Exception e){e.printStackTrace ();} 9V|E1-")E  
} 1~["{u  
| \ s2  
&p/S>qKu#  
private void processErrorCode(int nErrorCode) :iP>z}h  
{ |pfhrwJp  
System.err.println("Error Code : " + nErrorCode); >t1_5  
} QH@Q\ @,  
fG:PdIJ7_  
Xz;et>UD*B  
//停止文件下载 .OVW4svX  
public void siteStop() lcu("^{3  
{ FQ;4'B^k]  
bStop = true; <dju6k7uz  
for(int i=0;i<nStartPos.length;i++) ;cM8EU^.  
fileSplitterFetch.splitterStop(); !yoSMI-  
<'PR;g^#  
v
7s]  
} XNc"kp? z  
} .8u$z`j  
//负责部分文件的抓取 d$2@,  
**FileSplitterFetch.java [VY8?y  
*/ A)b)ff,  
package NetFox; tIz<+T_  
ig2{lEkF  
dzjBUD  
import java.io.*; :BewH?Ku  
import java.net.*; 2ApDpH`fiJ  
8m#}S\m  
3v8V*48B$  
public class FileSplitterFetch extends Thread { }-R
EBrb-  
Cfv L)f  
.){e7U6b{  
String sURL; //File URL Uq<a22t@  
long nStartPos; //File Snippet Start Position 9@KUqoX  
long nEndPos; //File Snippet End Position {:};(oz)f  
int nThreadID; //Thread's ID k| _$R?  
boolean bDownOver = false; //Downing is over '1>g=Ic0  
boolean bStop = false; //Stop identical =oL8d6nI  
FileAccessI fileAccessI = null; //File Access interface YtwmlIar`  
\Dvl%:8  
/0B07B  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException no~OR Q  
{ `^ieT#(O  
this.sURL = sURL; yj}bY?4I  
this.nStartPos = nStart; Ns+)Y^(5  
this.nEndPos = nEnd; =yk Rki  
nThreadID = id; R-r+=x&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4*p_s8> >  
} 9%p7B~}E  
O:oU`vE  
.u&&H_ UmE  
public void run() KKeb ioW  
{ SY!`a:It  
while(nStartPos < nEndPos && !bStop) 4_6W s$x  
{ RZ#alFL,  
JfZL?D{NM  
C
?GvTc  
try{ ^%K1R;  
URL url = new URL(sURL); ;,F-6RNj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8]cv&d1f  
httpConnection.setRequestProperty("User-Agent","NetFox"); tJ?qcT?  
String sProperty = "bytes="+nStartPos+"-"; `l[6rf_.  
httpConnection.setRequestProperty("RANGE",sProperty); 1S*8v7  
Utility.log(sProperty); w>NZRP_3  
?/`C~e<J  
R`Ys;g/!  
InputStream input = httpConnection.getInputStream(); <;$Sa's,LE  
//logResponseHead(httpConnection); .c=$ bQ>^  
u%+6Mp[E  
jQ.>2-;H9  
byte[] b = new byte[1024]; !u
j!  
int nRead; Lu8%qcC  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) nhVK?  
{ TnvHO_P,  
nStartPos += fileAccessI.write(b,0,nRead); kbIY%\QSO  
//if(nThreadID == 1) JEK%yMj  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F"B<R~  
} Sah<sb=  
}$&T O$LX  
mr{k>Un\  
Utility.log("Thread " + nThreadID + " is over!"); %:'1_@Ot2  
bDownOver = true; @!L@UP0
 
//nPos = fileAccessI.write (b,0,nRead); t7C!}'g&'  
} |:7EJkKZ  
catch(Exception e){e.printStackTrace ();} FT*yso:X/  
} 6SW|H"!!  
} ND9n1WZ&x  
u):%5F/  
WryW3];0OR  
//打印回应的头信息 )*^OPVt  
public void logResponseHead(HttpURLConnection con) >j(I[_g  
{ Q>SPV8s  
for(int i=1;;i++) O" X!S_R  
{ c"f-$^<  
String header=con.getHeaderFieldKey(i); 7(A G]  
if(header!=null) I&'S2=s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); M\Uc;:) H  
Utility.log(header+" : "+con.getHeaderField(header)); 2HvTM8  
else +H)!uLvaB  
break; V',m $   
} ^td!g1"<  
} jt'Y(u]2  
8^P2GG'+-  
&;NNUT>Q  
public void splitterStop() Q^1#xBd  
{ eu}:Wg2  
bStop = true; vjs|!O=oH  
} gNEzl
x8A  
H649J)v+m  
yO$r'9?,*  
} VuO)  
&|'Kut?8  
.swgXiRvs  
/* J#Ne:Aj_  
**FileAccess.java C$2o o@   
*//文件访问(定位，写) }OX>(  
package NetFox; _Ssv:xc,  
import java.io.*; %b-;Rn  
tvj'{W  
>PTu*6Z  
public class FileAccessI implements Serializable{  eo<~1w  
WoClT
b>F  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -Iruua7b  
RandomAccessFile oSavedFile; 8CnvvMf  
long nPos; 5JU(@}Db  
X*>o9J45V  
\DcC1W  
public FileAccessI() throws IOException ys.!S.k+  
{ :nbW.B3GV  
this("",0); $E4O^0%/p  
} X('Q;^`  
`3
>)BV<P  
L!+[]tB  
public FileAccessI(String sName,long nPos) throws IOException )K\k6HC.  
{ 6&OonYsP  
oSavedFile = new RandomAccessFile(sName,"rw"); uc"[qT(X  
this.nPos = nPos; My6]k?;}(  
oSavedFile.seek(nPos); J<5vs3[9  
} vUIK4uR.  
tI!R5q;k  
bb O;AiHD  
public synchronized int write(byte[] b,int nStart,int nLen) soQv?4  
{ !Lg}q!*%>V  
int n = -1; w=P<4bdT  
try{ {6=H/g=:i  
oSavedFile.write(b,nStart,nLen); MeK\eZ\  
n = nLen; y?R <g^A  
} fbx;-He!  
catch(IOException e) -fSKJo#}|  
{ i/O,`2  
e.printStackTrace (); &' Nk2{  
} $CQwBsYb=  
EbwZZSds1  
(PT?h>|St  
return n; g6a3MJV`  
} c J"]yG)=  
d,Dg"Z  
Z#cU#)`y1  
} um0}`Xq^  
q2j}64o_S  
B'BbTI,  
/* }&C!^v o  
**SiteInfoBean.java HU'`kimWb  
*/ [%)B%h`XGf  
package NetFox; KbuGf$Bv  
gx>mKSzy  
7q{v9xKy  
public class SiteInfoBean { BI]ut|Qw  
~cg+BAfu  
W*/s4 N  
private String sSiteURL; //Site's URL n`I jG  
private String sFilePath; //Saved File's Path nO.+&kA  
private String sFileName; //Saved File's Name ;~1/eF  
private int nSplitter; //Count of Splited Downloading File @Ozf}}#  
M:Y!k<p  
YT 03>!B  
public SiteInfoBean() '`goy%Wd  
{//nSplitter的缺省值为5 CK`3   
//default value of nSplitter is 5 }yC,
uEV  
this("","","",5); ,w58n%)H  
} kV(DnZ#jq  
kq.R(z+  
. =foXN  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9q,JqB  
{ |Nd.'|g,  
sSiteURL= sURL; JU%yqXO  
sFilePath = sPath; W-ND<=:Up  
sFileName = sName; MPEBinE?  
this.nSplitter = nSpiltter; Nxs%~wZ  
ThQEQ6y  
Ynh4oWUp  
} {^19.F  
@XG`D>%k  

+sbacMfq  
public String getSSiteURL()  [;LPeO  
{ >dC(~j{  
return sSiteURL; b%~3+c  
} R\Ynn^w  
?yM/j7Xn  
2'^OtM,  
public void setSSiteURL(String value) H2_>Av{m  
{ Zz*mf+  
sSiteURL = value; [6
gHi.`p'  
} %Ja{IWz9L  
]A<u eM  
AQNx%  
public String getSFilePath() fD}]Mi:V  
{ <.%8j\j(  
return sFilePath; z^HlDwsbm  
} 8RT0&[  

0}C}\1  
ps;o[gB@5  
public void setSFilePath(String value) Eq.zCD8A  
{ wm`"yNbD  
sFilePath = value; %
>:)
4A  
} :<7>-+pa  
V^5k>`A  
A)a+LW'=u  
public String getSFileName() 4Jy,IKPp  
{ j<-o{6r  
return sFileName; "N:]d*A\  
} "=TTsxyM6P  
$mg h.3z0  
m3!MHe~t  
public void setSFileName(String value) 8uD%]k=#!  
{ <^
c0bY1  
sFileName = value; nk,Mo5
iqV  
} T`<k4
ur  
`e;Sjf<  
ZTz(NS EK  
public int getNSplitter() x3F L/^S  
{ #K*q(ei,7h  
return nSplitter; ]x{H  
} _^sSI<&m  
^ J@i7FOb  
!Kqj&y5  
public void setNSplitter(int nCount) E1Aa2  
{ NP`ll0s  
nSplitter = nCount; ?B:wV?-`  
} eOO*gM=  
} MP&4}De  
 X_S]8Aa  
F7u%oLjr  
/* (=B7_jrl  
**Utility.java ^ /eSby  
*/ |2` $g  
package NetFox; sWzXl~JbF  
;8Q?`=a  
SL5DWZ  
public class Utility { }nERQq&A  
XzFqQ-H  
@?AE75E{  
public Utility() *jSc&{s~  
{ T $]L 5  
>a~FSZf  
\V\ET  
} TbM*?\7  
`.Q3s?1F  
//线程睡眠 0#GwhB  
public static void sleep(int nSecond) 3/<^R}w\  
{ J-?(sjIX  
try{ j'b4Sbs-f  
Thread.sleep(nSecond); 4KB?g7_*  
} *njB fH'
 
catch(Exception e) bv"({:x  
{ Bm>(m{sX>  
e.printStackTrace (); iEO2Bil]  
} EB<tX`Wp  
} #yxYL0CcA:  
hpKc_|un  
//日志 :WTvP$R  
public static void log(String sMsg) S$:S*6M@"  
{ iJ#oI@s  
System.err.println(sMsg); QZP;k!"w  
} 9:5NX3"p  
td$Jx}'A  
Z4sjH1W  
public static void log(int sMsg) TyXOd,%zl  
{ IUG.q8  
System.err.println(sMsg); Efd[ZJxS6  
} `G{t<7[[;  
} HYa!$P3}[  
AU\!5+RDB  
ZWW}r~d{  
/* v)pWx0l=  
**TestMethod.java W]]2Uo.  
*/ t$%}*@x7  
package NetFox; GUZi }a|=  
?E+XD'~  
;!Bkk9r"H  
public class TestMethod { 5mBk[{  
CBHWMetJ*  
cne[-E  
public TestMethod() sTYl' Ieg  
{ ///xx/weblogic60b2_win.exe 1 SZa\ ][@  
try{ 5n#&Hjb*F0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); D4T+Gk"n  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |,f6c Omf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); B}T72!a  
fileFetch.start(); l/M+JT~R  
} g}h0J%s
 
catch(Exception e){e.printStackTrace ();} I[C.iILL  
J(L$pIM  
p 1fnuN |,  
} 3P>@ :  
Dn!V)T  
Fm{y.URo  
public static void main(String[] args) |
mX8fRh  
{ C*<LVW{P  
new TestMethod(); |a3b2x,  
} --D`YmB  
} _"TG:RP  
点击下载更多相关资料