http断点续传简单实现（java)

/* 6 VuMx7W1  
**SiteFileFetch.java RE75TqYW  
*/ [>U =P`  
package NetFox; NYp46;  
import java.io.*; 3n=ftkI  
import java.net.*; .uu[MzMIu  
XSz)$9~hk  
-85W
/%  
public class SiteFileFetch extends Thread { xsdi\ j;n>  
0:4w@"Q  
qFYM2  
SiteInfoBean siteInfoBean = null; //文件信息Bean ju?D=n@i  
long[] nStartPos; //开始位置 G^/8lIj  
long[] nEndPos; //结束位置 Mi&jl_&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 TbA=bkj[4  
long nFileLength; //文件长度 &>%9JXU  
boolean bFirst = true; //是否第一次取文件 R3%&\<a)9  
boolean bStop = false; //停止标志 _V-pr#lP1  
File tmpFile; //文件下载的临时信息 ; )J\k2  
DataOutputStream output; //输出到文件的输出流 nf9NJ_8}4H  
B1Cu?k);.  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） l|&DI]gw  
public SiteFileFetch(SiteInfoBean bean) throws IOException *.F4?i2D  
{ use` y^c  
siteInfoBean = bean; 'Q F@@48  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #Vi:-zyY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Y|96K2BR  
if(tmpFile.exists ()) j?y_ H[Z  
{ L4-v'Z;  
bFirst = false; :LEC[</yvl  
read_nPos(); A
s-xO~+  
} ae|j#!~oi  
else K/ 5U;oC  
{ 1=Nh<FuQ  
nStartPos = new long[bean.getNSplitter()]; ct![eWsuB  
nEndPos = new long[bean.getNSplitter()]; ~zT743  
} l's*HEx
R  
I&G"{Dl94  
~V6wcXd  
2Bg0 M  
} L:E?tR}H  
eT6T@C
](  
_/`H<@B_U  
public void run() q,v)X  
{ 9S]]KEGn4  
//获得文件长度 Cmj+>$')0  
//分割文件 Yb;$z'  
//实例FileSplitterFetch XdxSi"+  
//启动FileSplitterFetch线程 3r-oZ8/n  
//等待子线程返回 $;%k:&\f  
try{ Th>ff)~e  
if(bFirst) 8%Hc%T[RnT  
{ lLi)?  
nFileLength = getFileSize(); K)[DA*W  
if(nFileLength == -1) qaZQ1<e  
{ p]erk  
System.err.println("File Length is not known!"); ] g]^^  
} GjH$!P=.  
else if(nFileLength == -2) Ny2. C?2  
{ pW4$$2S?9  
System.err.println("File is not access!"); {ZIEIXWb2  
} >#~>!cv6D  
else J_rb3  
{ 0S71&I$u]  
for(int i=0;i<nStartPos.length;i++) G24Ov&H  
{ 7/b\N
LeJ'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); FH7h?!|t  
} ee\QK,QV  
for(int i=0;i<nEndPos.length-1;i++) zVyMmw\  
{ -"~XI~a@Wo  
nEndPos = nStartPos[i+1]; {7Q)2NC  
} b:t|9FE%  
nEndPos[nEndPos.length-1] = nFileLength; tqXr6+!Q  
} fobnK~2  
} ^9fY
%98  
%v)O!HC}  
Vc*"Q8aZ~  
//启动子线程 -fCR^`UOS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^e\H V4s  
for(int i=0;i<nStartPos.length;i++) Zb}U 4  
{ g`\5!R1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `b?o%5V2x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), S}/5W  
nStartPos,nEndPos,i); ^bG91"0A  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !@3"vd{^  
fileSplitterFetch.start(); _`.Wib+  
} My<.^~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2D)B%nM[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'B yB1NL  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", It:,8  
nEndPos = " + nFileLength); 1=z6m7@'-  
// fileSplitterFetch[nPos.length-1].start(); 4U>g0  
:Fh#"<A&&  
l
#bE_PD;  
//等待子线程结束 BHNEP |=  
//int count = 0; +*L<"@  
//是否结束while循环 k$3Iv"gbx  
boolean breakWhile = false; Cm%|hk>fQ  
</]a`h
]  
#sM`>KG6T1  
while(!bStop) /?Hq  
{ nAaY5s0D  
write_nPos(); xVN(It7g  
Utility.sleep(500); jG["#5<?  
breakWhile = true; H[2W(q6  
@id!F<+%oD  
H;{IOBo  
for(int i=0;i<nStartPos.length;i++) IN7Cpg~9%  
{ G3dA`3  
if(!fileSplitterFetch.bDownOver) QERj`/
g  
{ |'qvq/#^  
breakWhile = false; /(8"9Sfm  
break; ~CuJ$(9Y  
} R
4vf  
} Te2C<c  
if(breakWhile) (tvfF0~  
break; (lg~}Jwq  
N$N7aE$  
%E2V$l0  
//count++; g&I
|@$\  
//if(count>4) ; ,n}>iTE  
// siteStop(); _E2
W%N  
} L@"&s#~=3  
{uN-bl?o  
s"5wnp6pW  
System.err.println("文件下载结束！"); <f#pS[A  
} z1nKj\AM2  
catch(Exception e){e.printStackTrace ();} "7J38Ej\  
} ZRj/lQ2D  
moRo>bvN~  
?7uK:'8  
//获得文件长度 x%W%  
public long getFileSize() *i>hFNLdOM  
{ NA=m<n#  
int nFileLength = -1; 4*'ZabDD  
try{ i}5M'~F  
URL url = new URL(siteInfoBean.getSSiteURL()); apjoIO-<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q zp!)i  
httpConnection.setRequestProperty("User-Agent","NetFox"); RQ;w$I\  
$Y M(NC  
9Ed=`c  
int responseCode=httpConnection.getResponseCode(); -ImVXy]?  
if(responseCode>=400) YI>9C 76L  
{ f4Ob4ah!(  
processErrorCode(responseCode); XtqhK"f%  
return -2; //-2 represent access is error ,\T7{=ZG\!  
} A1n4R  
{F;"m&3Lt  
{r%T_BfY  
String sHeader; '^`iF,rg  
wZVLpF+7  
XT?wCb41R  
for(int i=1;;i++) OXnTD!m>{  
{ P9W?sPnC5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5zOC zm  
//Utility.log(in.readLine()); 3_8W5J3I  
sHeader=httpConnection.getHeaderFieldKey(i); Qb|@DMq%  
if(sHeader!=null) \k{d'R#~(  
{ Mm;[f'{M)  
if(sHeader.equals("Content-Length")) $18?Q+?3  
{ \5}*;O@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _2hZGC%&E  
break; !j%uwje\  
} U/-k'6=M  
} />wE[`  
else gC(@]%  
break; L;WFHIE  
} 0BH-kr  
} 3$S~!fh  
catch(IOException e){e.printStackTrace ();} ZW4$Ks2]Y  
catch(Exception e){e.printStackTrace ();} h>F"GR?U_(  
v 6s]X*l?  
Rg^ps  
Utility.log(nFileLength); !%[fi[p  
hj}PL  
OF2W UcQ  
return nFileLength; ^*w}+tB  
} "T*1C=  
sX-@ >%l  
3m$ck$  
//保存下载信息（文件指针位置） axOEL:-|Bu  
private void write_nPos() ?aI.Z+#  
{ M:dH>  
try{ f!H/X%F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H%>^_:h  
output.writeInt(nStartPos.length); Lrmhr3 w5  
for(int i=0;i<nStartPos.length;i++) > `mV^QD  
{ %=$Knc_!T^  
// output.writeLong(nPos); >.I9S{7  
output.writeLong(fileSplitterFetch.nStartPos); uAV7T/'  
output.writeLong(fileSplitterFetch.nEndPos); +,cd$,18  
} ra2{8 x  
output.close(); wbvOf X  
} ksTK'7*  
catch(IOException e){e.printStackTrace ();} 4)8e0L*[B?  
catch(Exception e){e.printStackTrace ();} P&Uj?et"  
} )x~/
qHt  
m2P&DdN[  
$f%om)  
//读取保存的下载信息（文件指针位置）
@1xIph<z  
private void read_nPos() z{&z  
{ qzEv!?)a  
try{ 56
MY@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); YrYmPSb=  
int nCount = input.readInt(); tfD7!N{  
nStartPos = new long[nCount]; x6^Y&,y9kU  
nEndPos = new long[nCount]; 4oL
.Bt  
for(int i=0;i<nStartPos.length;i++) OL%}C*Zq  
{ +z:>Nl  
nStartPos = input.readLong(); /4N?v. jf  
nEndPos = input.readLong(); ioEjbqD<  
} ?^2nrh,n+  
input.close(); q!W=U8`  
} hC9EL= A  
catch(IOException e){e.printStackTrace ();} 97qf3^gGd  
catch(Exception e){e.printStackTrace ();} BMqr YW  
} 7t1as.  
/]U;7)  
(G/(w%#7_  
private void processErrorCode(int nErrorCode) R>]7l!3^1  
{ |sY  
System.err.println("Error Code : " + nErrorCode); )0DgFA6k_  
} q#SEtyJL  
T "hjL  
wph8ln"C-  
//停止文件下载 ;mRZ_^V;  
public void siteStop() B"zB=Aw  
{ Xk/iyp/  
bStop = true; ~y?Nn8+&f  
for(int i=0;i<nStartPos.length;i++) $VB dd~f  
fileSplitterFetch.splitterStop(); dwQ1~  
)2#&l  
"LJV}L  
} SF9NS*mr  
} q"6$#o{~U  
//负责部分文件的抓取 IUDH"~f  
**FileSplitterFetch.java ~Uey'Xz  
*/  wlsx|  
package NetFox; ;^u,[d  
3%Eu$|B  
:U *8S\$  
import java.io.*; n#}~/\P6  
import java.net.*; k14<E/  
F" M  
4w#2m>.  
public class FileSplitterFetch extends Thread { Srz8sm;  
N{~P}Sw  
wGw~ F:z  
String sURL; //File URL }+bo?~2E&  
long nStartPos; //File Snippet Start Position tW94\3)1  
long nEndPos; //File Snippet End Position O9E:QN<U`*  
int nThreadID; //Thread's ID LokH4A17U  
boolean bDownOver = false; //Downing is over TOF V`7q;3  
boolean bStop = false; //Stop identical RwYFBc  
FileAccessI fileAccessI = null; //File Access interface ?{jey_]M  
S3i p?9  
#oFyi @U  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException YM6 J:89  
{ 4c95G^dZ  
this.sURL = sURL; UCK;?]  
this.nStartPos = nStart; 0[M2LF!m  
this.nEndPos = nEnd; =[&+R9
s  
nThreadID = id; 6)*B%$?x  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _ E-\aS{  
} _)~1'tCs}h  
qp/1tC`  
]uMZvAjb  
public void run() Yh!=mW!OY  
{ Shn=Q  
while(nStartPos < nEndPos && !bStop) B :S8{  
{ de)4)EzUP  
c;Tp_e@  
Wh)  
try{ U\B9Ab  
URL url = new URL(sURL); 6wj o:I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u$C\#y7  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]1XtV<  
String sProperty = "bytes="+nStartPos+"-"; B@NBN&Fr  
httpConnection.setRequestProperty("RANGE",sProperty); }( CYok  
Utility.log(sProperty); HfgTc h  
1#%H!GKvTU  
ot[ZFF\  
InputStream input = httpConnection.getInputStream(); AIY 1sSK  
//logResponseHead(httpConnection); |JF,n~n  
*4NY"EwjN  
gzn:]Y^  
byte[] b = new byte[1024]; :r ~iFP*  
int nRead; J(@" 7RX  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) jf`w8*R  
{ =}kISh  
nStartPos += fileAccessI.write(b,0,nRead); mXyN{`q=  
//if(nThreadID == 1) 4w=v /WDo  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fM7B<eB  
} ?jUgDwc(w  
/3Gq&[R{  
ZOcpF1y  
Utility.log("Thread " + nThreadID + " is over!"); M2p|&Z%  
bDownOver = true; 8<mloM-4  
//nPos = fileAccessI.write (b,0,nRead); YY:{/0?  
} yn$1n
t4  
catch(Exception e){e.printStackTrace ();} iE HWD.u  
} (]T[n={Y  
} gd]S;<Jh  
ybqmPT'|_  
=0
]K(p,  
//打印回应的头信息 y6tqemz  
public void logResponseHead(HttpURLConnection con) L.yM"  
{ UPr& `kaJ  
for(int i=1;;i++) d~rA`!s7`  
{ &9)/"  
String header=con.getHeaderFieldKey(i); 036m\7+Qj  
if(header!=null) 5,s@K>9l;  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (lS[a  
Utility.log(header+" : "+con.getHeaderField(header)); ZD'mwj+K  
else `h'l"3l  
break; )^ZC'[93  
} Hv/5)  
} >6jal?4u-  
V^R,j1*  
" "m-5PGYo  
public void splitterStop() 9 @ <  
{ 9aLd!PuTN  
bStop = true; gC(S(osF  
} 4'dN7E1*f  
_s#]WyU1g  
)Sb-e(sl  
} <mlN\BcX;  
l
+>Y
  
!;h&@LXG(  
/* 2 G2+oS ?  
**FileAccess.java \A011R&  
*//文件访问(定位，写) B }euIQB  
package NetFox; F nXm;k,9*  
import java.io.*; |8~)3P k  
k(^TXUK\o  
Y:O|6%00Y  
public class FileAccessI implements Serializable{ %a WRXW@c  
K mH))LIv  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9xz@2b@  
RandomAccessFile oSavedFile; *cCx]C.~  
long nPos; j3;W-c`5  
&U?4e'N)T  
b way+lh  
public FileAccessI() throws IOException @@U  
{ >AX_"Q~  
this("",0); ZCj1Cz]"l<  
} SyI~iW#Y1  
Qt{){u
E  
iTq&h=
(n  
public FileAccessI(String sName,long nPos) throws IOException tt2 S.j  
{ oF>`>  
oSavedFile = new RandomAccessFile(sName,"rw"); Z81;Y=(  
this.nPos = nPos; 9/e>%1.  
oSavedFile.seek(nPos);  c`\/]  
} ]tT=jN&(  
4]tg!ks  
og35Vs0  
public synchronized int write(byte[] b,int nStart,int nLen) =|aZNHqH  
{ `<d.I%}
 
int n = -1; n@ba>m4{  
try{ G!sfp}qW  
oSavedFile.write(b,nStart,nLen); ,LxZbo!  
n = nLen; 9uWg4U  
} n/(}|xYU  
catch(IOException e) ]58~b%s  
{ Cy uRj[;B  
e.printStackTrace (); aY?VP?BL  
} %n9ukc~$p  
"GZ}+K*GG  
1c#\CO1l  
return n; KCbJ^Rln  
} S-o
)d  
P HOngn  
{ "Cu)AFy  
}
Hy\q{  
`.O$RwC&7B  
FWW@t1)  
/* /iM1   
**SiteInfoBean.java G\MeJSt*  
*/ K;"oK  
package NetFox;  0LL65[  
V6[jhdb  
%La7);SeY  
public class SiteInfoBean { 7glf?oE  
^`lrKk  
pXlqE,  
private String sSiteURL; //Site's URL TA/hj>rV  
private String sFilePath; //Saved File's Path b3[[ Ah-  
private String sFileName; //Saved File's Name [Z2[Iy  
private int nSplitter; //Count of Splited Downloading File n:wAxU  
1)h<
)  
@]#[TbNo  
public SiteInfoBean() 'D`lVUB  
{//nSplitter的缺省值为5 qGV(p}$O  
//default value of nSplitter is 5 B,_K mHItd  
this("","","",5); ]5QXiF8`  
} AEnkx!o  
KG(FA  
VT4>6u}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) E"p _!!1  
{ H/M]YUs/3  
sSiteURL= sURL; tlD^"eq4:  
sFilePath = sPath; k"gm;,`  
sFileName = sName; ~ L%,9  
this.nSplitter = nSpiltter; /v<Gt%3X  
(n.IK/:  
iOhX\@&  
} Q`'cxx  
\F`>zY2$%  
F7jkl4  
public String getSSiteURL() =J)-#|eZG  
{ f?=0Wzb  
return sSiteURL; m%})H"5  
} /~WBqcl  
!9HWx_,|Z  
oXht$Q  
public void setSSiteURL(String value) ~Azj 
Y8  
{ 9v;[T%%  
sSiteURL = value; cy!P!t,@  
} &L?]w=*  
eP:\\; ;  
l$j~p=S$F  
public String getSFilePath() X6Z/xb@  
{ q{  
return sFilePath; > O?<?  
} .YvIVQ  
5655)u.N8  
VhLfSN>W  
public void setSFilePath(String value) q]pHD})O  
{ @|"K"j#  
sFilePath = value; n+&8Uk  
} P(I%9  
Ws2?sn#x  
ji4bz#/B0  
public String getSFileName() lY@2$q9BT  
{ `5oXf  
return sFileName; 2i#Ekon  
} ?o6#i3k#'  
eB9&HD:  
O>vCi&  
public void setSFileName(String value) Hp ;$fQ  
{ ucz~y!4L{  
sFileName = value; vJi<PQ6  
} A =Z$H2  
ztHx) !  
}BT0dKx  
public int getNSplitter() 0/|Ax-dK  
{ !PeSnO  
return nSplitter; tj*0Y-F~  
} TYR \K  
Tr}XG  
ep},~tPZn  
public void setNSplitter(int nCount) V8WSJ=-&  
{ Z*b l J5YC  
nSplitter = nCount; B>cT<B  
} l+&DBw[  
} Zw{?^6;cS  
#/H2p`5  
~;]zEq-hG  
/* TUwX4X6m  
**Utility.java N8kNi4$mp=  
*/ V'dw=W17V  
package NetFox; m##!sF^k~J  
9* 3;v;F  
-~JYfj@  
public class Utility { cVMRS
p  
HrZX~JnTmf  
:|ahu  
public Utility() 6XCFL-o-  
{ Ja&S
_'P[  
&M3KJ I0L  
GB}=  
} dP_bFUzg  
,gG RCp  
//线程睡眠 W?wt$'  
public static void sleep(int nSecond) 8_Uhh
5[  
{ m:0[as=  
try{ hP.Km%C)0n  
Thread.sleep(nSecond); g2==`f!i  
} t\YM Hq<Y  
catch(Exception e) +hispU3ia  
{ P{n*X  
e.printStackTrace ();  W{Z7=  
} W?kJ+1"(  
} m`$Q/SyvG  
)/Eu=+d  
//日志 q=`n3+N_H~  
public static void log(String sMsg) &\cS{35  
{ /joY? T  
System.err.println(sMsg); nnT#S  
} +%klS `_  
,g0t&jITo  
="vg/@.>i  
public static void log(int sMsg) ]=i('|YG  
{ D{y7[#$h$  
System.err.println(sMsg); H=~7g3  
} *[b>]GXd49  
} 88S:E7 $  
Y}2Sr-@u  
gE^pOn  
/* ]s)Y">6  
**TestMethod.java Wuk8&P3  
*/ 0m> 8  
package NetFox; ]i0=3H2  
w8UUeF  
t18j2P>`  
public class TestMethod { EVaHb;  
K*,,j\Q.  
LCj3{>{/=  
public TestMethod() /5L\:eX%  
{ ///xx/weblogic60b2_win.exe ?mK&Slh.  
try{ 3pW4Ul@e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); H-u SdT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); d2gYBqag  
SiteFileFetch fileFetch = new SiteFileFetch(bean); rMjb,2*rC7  
fileFetch.start(); kF,ME5%  
} /)K;XtcN  
catch(Exception e){e.printStackTrace ();} j%bC9UkE3  
|7A}LA  
Rcw[`q3/  
} T!41[vm(  
Ck%if  
BB69U  
public static void main(String[] args) -
}!miV  
{ OX]P;#4tU  
new TestMethod(); BaIuOZ@,  
} s]kzXzRC?  
} c[ 0`8s!  
点击下载更多相关资料