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http断点续传简单实现(java)

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/* sXxO{aeev  
**SiteFileFetch.java 4(82dmKO  
*/ z3]U% y(,  
package NetFox; Mk[`HEO  
import java.io.*; YqgW8 EM  
import java.net.*;  4&D="GA  
7krA+/Qr(  
Fev3CV$  
public class SiteFileFetch extends Thread { =Qrz|$_rv  
OB22P%  
?sYjFiE  
SiteInfoBean siteInfoBean = null; //文件信息Bean &v,p_'k  
long[] nStartPos; //开始位置 U@nwSfp:G  
long[] nEndPos; //结束位置 7g9^Jn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ziimz}WHF  
long nFileLength; //文件长度 ".f:R9-  
boolean bFirst = true; //是否第一次取文件 5g5NTm`=<  
boolean bStop = false; //停止标志 Umg81!  
File tmpFile; //文件下载的临时信息 WKsx|a]U  
DataOutputStream output; //输出到文件的输出流 P hu| hx<  
n bk(F D6  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) [[Z>(d$8  
public SiteFileFetch(SiteInfoBean bean) throws IOException TzGm562o%  
{ U.OX*-Cd  
siteInfoBean = bean; +`-a*U94  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /MH@>C _  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z"X*FzFo  
if(tmpFile.exists ()) 8 -A7  
{ VsEAo  
bFirst = false; u(702S4  
read_nPos(); gH3kX<e  
} L0tKIpk  
else B_glyC  
{ "~C#DZwt{  
nStartPos = new long[bean.getNSplitter()]; D5u"4\g< &  
nEndPos = new long[bean.getNSplitter()]; #Ca's'j&f  
} (}1f]$V  
VAGMI+ -  
4tJ4X' U  
_`>7 Q) ,7  
} rJp6d :M  
<|3v@  
/g'-*:a  
public void run() XWpnZFjE  
{ ^1=|(Z/  
//获得文件长度 +Q31K7Gr  
//分割文件 pIiED9  
//实例FileSplitterFetch +z0}{,HX  
//启动FileSplitterFetch线程 : "te-  
//等待子线程返回 "B3:m-'  
try{ f*{;\n (.t  
if(bFirst) Ba|}C(Ws?  
{ i0Q _f!j  
nFileLength = getFileSize(); Eu.qA9,@U  
if(nFileLength == -1) @H0%N53nE  
{ _x 6E_i-(  
System.err.println("File Length is not known!"); q- (N Zno  
} 3Lki7QW`  
else if(nFileLength == -2) LoE(W|nj  
{ ;<@6f@  
System.err.println("File is not access!"); rq["O/2  
} lFGxW 5  
else tkqBCKpDa  
{ OG7v'vmY  
for(int i=0;i<nStartPos.length;i++) w*%$ lhp!  
{ zB" `i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); EZQ+HECpK  
} e.|RC  
for(int i=0;i<nEndPos.length-1;i++) hRIS [#z;U  
{ vx}Z  
nEndPos = nStartPos[i+1]; Ej09RO"pB  
} 5|G3t`$pa  
nEndPos[nEndPos.length-1] = nFileLength; sJK:xk.6!  
} (Zg'pSs)  
} :*:fu n  
&d3'{~:  
I@Z*Nu1L  
//启动子线程 np\2sa`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *M<BPxh0w]  
for(int i=0;i<nStartPos.length;i++) Dh(T) yc  
{ !riMIl1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f\_!N "HW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [j]J_S9jJ  
nStartPos,nEndPos,i); ec4%Wk2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]!G>8Rc  
fileSplitterFetch.start(); <`j[;>O  
} 2vdQ&H4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *a,.E6C*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |4> r"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =#2qX> ?  
nEndPos = " + nFileLength); ^}/ E~Sg7\  
// fileSplitterFetch[nPos.length-1].start(); W$Q)aA7  
,9tbu!Pvq  
%_R|@cyD  
//等待子线程结束 ^Xy$is3  
//int count = 0; ,x"yZ  
//是否结束while循环 dwbY"t[9  
boolean breakWhile = false; #C;zS9(]B  
P,;b'-5C  
pebx#}]p-  
while(!bStop) -C-OG}XjI  
{ 9#T%bB "J  
write_nPos(); ddq 1NW  
Utility.sleep(500); 1;:t~Y  
breakWhile = true; @23R joK  
P[I*%  
d?&!y]RS#  
for(int i=0;i<nStartPos.length;i++) "K+N f  
{ vgA!?P3  
if(!fileSplitterFetch.bDownOver) fZV8 o$V  
{ +V);'"L  
breakWhile = false; U]!.~ji3  
break; RJ}yf|d-C  
} fJ&<iD)6  
} [zTYiNa  
if(breakWhile) RTgA[O4J  
break; Ns|V7|n]  
u->@|tEq  
OT}Yr9h4  
//count++; O`[iz/7m  
//if(count>4) yEpN,A  
// siteStop(); $mI:Im`s  
} 5}MlZp  
ELrZ8&5G  
"gbnLKs  
System.err.println("文件下载结束!"); q?Ku}eID3  
} UC+7-y,  
catch(Exception e){e.printStackTrace ();} le^_6| ek  
} > 0Twr  
BsK|:MM]  
aFr!PQp4{  
//获得文件长度 k99gjL`  
public long getFileSize() 6a%:zgkOpu  
{ -_EY$ ?4  
int nFileLength = -1; )`s;~_ZZ  
try{ >^H'ZYzw  
URL url = new URL(siteInfoBean.getSSiteURL()); Cwsoz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ck3QrfM  
httpConnection.setRequestProperty("User-Agent","NetFox"); =|gJb|?w  
3Zaq#uA  
])QO%  
int responseCode=httpConnection.getResponseCode(); jV4hxuc$  
if(responseCode>=400) ~X~xE]1o|U  
{ l~fh_IV1  
processErrorCode(responseCode); xgtJl}L  
return -2; //-2 represent access is error B%eDBu ")  
} ^Cc8F3os=  
YHO;IQ5  
M$&WM{Pr^  
String sHeader; Q3BLL` W~  
zM_DE  
x5fgF;  
for(int i=1;;i++) rb *C-NutE  
{ J}) $  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wuIsO;}/9  
//Utility.log(in.readLine()); c_ qcb7<~.  
sHeader=httpConnection.getHeaderFieldKey(i); - - i&"  
if(sHeader!=null) \'; t*  
{ ;# R3k  
if(sHeader.equals("Content-Length")) nIV.9#~&  
{ ;w+:8<mM}a  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5Cc6 , ]  
break; Dm|gSv8d,  
} g{A3W) [ b  
} <ELziE~>V  
else BcZEa^^~os  
break; %z-dM` i  
} f[JI/H>  
} d s|8lz,  
catch(IOException e){e.printStackTrace ();} ?jNF6z*M6  
catch(Exception e){e.printStackTrace ();} qeQC&U y;  
Kf05<J!  
&*(n<5 wt  
Utility.log(nFileLength); 2I]]WBW#:  
rV8(ia  
#$rf-E5g-K  
return nFileLength; 00`bL  
} gro7*<  
ilDJwZg#  
:SQDqG   
//保存下载信息(文件指针位置) < 72s7*Rv  
private void write_nPos() Yl)eh(\&J  
{ |u^)RB  
try{ 0(Y%,q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wUru1_zjO  
output.writeInt(nStartPos.length); Ud>`@2  
for(int i=0;i<nStartPos.length;i++) !sg%6H?}  
{ $xRo<,OV+  
// output.writeLong(nPos); zQL!(2  
output.writeLong(fileSplitterFetch.nStartPos); UfK4eZx*`  
output.writeLong(fileSplitterFetch.nEndPos); &Q'\WA'  
} lQh E]m>+  
output.close(); CDQJ bvx  
} I;Al? &uw  
catch(IOException e){e.printStackTrace ();} \yih 1Om>~  
catch(Exception e){e.printStackTrace ();} U9<_6Bsd  
} _-@ZOhw&  
*C4~}4WT\  
%'{V%IXQ  
//读取保存的下载信息(文件指针位置) -!XrwQyk  
private void read_nPos() "2ZIoa!^  
{ 5*JV )[  
try{ {[Uti^)m%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %:" RzHN  
int nCount = input.readInt(); Jq# [uX  
nStartPos = new long[nCount]; hf_R\C(c  
nEndPos = new long[nCount]; |f"-|6  
for(int i=0;i<nStartPos.length;i++) q$MHCq;  
{ |9+bSH9  
nStartPos = input.readLong(); _n< LVd E  
nEndPos = input.readLong(); >lA7*nn  
} -`-ACWeNV  
input.close(); jv*Dg (  
} pZu?V"R  
catch(IOException e){e.printStackTrace ();} =RQ )$ %  
catch(Exception e){e.printStackTrace ();} IM[54_I  
} AU0$A403  
Q8 -3RgAw  
ZvUp#8x(3  
private void processErrorCode(int nErrorCode) 2#'rk'X,K  
{ | d~B]65t  
System.err.println("Error Code : " + nErrorCode); V)2"l"Kt  
} +7Sf8tg\  
&\&'L|0F  
3sS=?q  
//停止文件下载 NV&;e[z  
public void siteStop() 0FG5_t"",\  
{ hbV E; 9  
bStop = true; |)^clkuGX  
for(int i=0;i<nStartPos.length;i++) !$D&6M|C8l  
fileSplitterFetch.splitterStop(); w|&,I4["  
:0B |<~lX  
40 A&#u9o  
} UE"7   
} HvAE,0N  
//负责部分文件的抓取 j?=VtVP  
**FileSplitterFetch.java H9sZR>(^  
*/ $ b4*/vMr  
package NetFox; d?JAUbqy  
+VwV5iy[`  
l<$rqz3D  
import java.io.*; D`V6&_. p  
import java.net.*; +z+ F-  
et@">D%;]  
'^hsH1  
public class FileSplitterFetch extends Thread { :]EP@.(  
=\M)6"}y}  
E yd$fcRK  
String sURL; //File URL @o`sf-8x  
long nStartPos; //File Snippet Start Position +IvNyj|  
long nEndPos; //File Snippet End Position &xgZF Sq  
int nThreadID; //Thread's ID 5xhM0 (  
boolean bDownOver = false; //Downing is over [C~fBf5  
boolean bStop = false; //Stop identical FU[*8^Z  
FileAccessI fileAccessI = null; //File Access interface a-fv[oB  
Og +)J9#  
>Q&CgGpW$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException E\ tL   
{ [9LxhPi  
this.sURL = sURL; 8IeI0f"l)  
this.nStartPos = nStart; '[%jjUU  
this.nEndPos = nEnd; ?qy*s3 j'M  
nThreadID = id; J l\'V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3]N q@t  
} N5yJ'i~,M  
>A<Df  
=`JW1dM  
public void run() cbfD B^_  
{ z23#G>I&  
while(nStartPos < nEndPos && !bStop) 46ILs1T6  
{ l/[pEUYU  
V5~fMsse  
)u<eO FI+  
try{ su}&".e^  
URL url = new URL(sURL); Z A[)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 00"CC  
httpConnection.setRequestProperty("User-Agent","NetFox"); /\d(c/,4  
String sProperty = "bytes="+nStartPos+"-"; rjXnDh]MC  
httpConnection.setRequestProperty("RANGE",sProperty); *u}'}jC1X  
Utility.log(sProperty); 3\1#eK'TK.  
fSbS(a  
'(tj[&aL  
InputStream input = httpConnection.getInputStream(); @`6}`k  
//logResponseHead(httpConnection); X6'H`E[  
jKS!'?  
QPX`l0V  
byte[] b = new byte[1024]; 3EI]bmi~  
int nRead; S.1( 3j*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7H4L-J3  
{ P:qz2Hw  
nStartPos += fileAccessI.write(b,0,nRead); nX)f'[ 7  
//if(nThreadID == 1) g@Ld"5$^2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &Bm&i.r  
} 02(h={  
7 I@";d8~  
qIz}$%!A  
Utility.log("Thread " + nThreadID + " is over!"); mf$Sa58  
bDownOver = true; g &*mozs  
//nPos = fileAccessI.write (b,0,nRead); f\ 'T_  
} i@XB&;*c\  
catch(Exception e){e.printStackTrace ();} &~'S)Nun  
} i*'Z3Z)  
} ;?zF6zvQ  
\X5 3|Y;=  
VtWT{y5Ec  
//打印回应的头信息 _W}(!TKO  
public void logResponseHead(HttpURLConnection con) TU%bOAKF\  
{ "T7>)fbu  
for(int i=1;;i++) zSKKr?{  
{ GB =bG%Tb  
String header=con.getHeaderFieldKey(i); bJwc1AJgH  
if(header!=null) [ZD[a6(94  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); hXc}r6<B  
Utility.log(header+" : "+con.getHeaderField(header)); AX;c}0g  
else '$?du~L-  
break; 'AWp6L@  
} F5U|9<  
} sBU_Ft  
Wxn#Rk#>  
JCD?qeTg  
public void splitterStop() or!!s 5[d  
{ e}e6r3faz  
bStop = true; p31oL{D  
} WFem#hq   
7E\g &R.  
8ljuc5,J  
} uFo/s&6K  
kM;o0wi  
l sr?b  
/* +(&|uq^  
**FileAccess.java XhN{S]Wn  
*//文件访问(定位,写) </=3g>9Z  
package NetFox; 5{X*a  
import java.io.*; `7\H41%\pp  
A? r^V2+j  
eF5;[v  
public class FileAccessI implements Serializable{ ^BiP LQ  
n]iyFZ`9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %J!NL0x_  
RandomAccessFile oSavedFile; +{e`]t>_  
long nPos; G\ex^&M  
,56;4)cv  
c0ZaFJ  
public FileAccessI() throws IOException N&m_e)E5c  
{ 5gshKmt_  
this("",0); V&iS~V0.  
} wDKELQ(y H  
{OP~8e"  
'yr{^Pek  
public FileAccessI(String sName,long nPos) throws IOException ~b6GrY"vB  
{ ? |VysJ  
oSavedFile = new RandomAccessFile(sName,"rw"); TF2KZL#A|  
this.nPos = nPos; pV=@sz,G  
oSavedFile.seek(nPos); 0>FE%  
} Y{+3}drJE  
*)D1!R<\,R  
:j,}{)5=  
public synchronized int write(byte[] b,int nStart,int nLen) $DE&J4K  
{ CmHyAw(  
int n = -1; `{o$F ::(  
try{ RG}}Oh="v  
oSavedFile.write(b,nStart,nLen); ,H{={aln  
n = nLen; 4.w"(v9V  
} MUwxgAG`G  
catch(IOException e) J|5Ay1eF-  
{ dB7ZT0L\  
e.printStackTrace (); F 7LiG9H6`  
} t^U^Tr  
SiTeB)/  
M1{(OY(G  
return n; s[X B#)H4  
} $>r5>6  
oY.\)eJ~>  
iRt*A6`m+  
} vaB!R 0  
iRve)   
taDQ65  
/* " " %#cDR  
**SiteInfoBean.java LGVlc@0'  
*/ |,sM ST%  
package NetFox; $^h?:L:1n  
B}\BeFt'  
t9` Ed>a  
public class SiteInfoBean { Ct!S Tk[2  
>lLo4M 3  
A ~&+F>Z  
private String sSiteURL; //Site's URL X"<|Z]w  
private String sFilePath; //Saved File's Path @GeHWv  
private String sFileName; //Saved File's Name Ep ">v>"  
private int nSplitter; //Count of Splited Downloading File bV6V02RF  
2 Y+:,ud\  
ri=+(NKo-  
public SiteInfoBean() doLNz4W  
{//nSplitter的缺省值为5 wW5Yw i  
//default value of nSplitter is 5 i/$SN-5}1  
this("","","",5); ,YB1 y)x  
} |^Kjz{  
5[R?iSGL1  
l$M +.GB<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gtYRV*^q  
{ "8/dD]=f^a  
sSiteURL= sURL; m~>@BCn;  
sFilePath = sPath; [W;[v<E;  
sFileName = sName; ^y Vl"/  
this.nSplitter = nSpiltter; 1;&T^Gdj  
nk/vGa4  
D=&K&6rr  
} ?,XC =}  
9@y3IiZ"}  
2w4MJ,Uw  
public String getSSiteURL() ri+U0[e3  
{ vr4S9`,  
return sSiteURL; Ue7 6py9  
} [:B*6FXMN~  
<|H ?gfM  
m UgRm]  
public void setSSiteURL(String value) XTo8,'UaP  
{ E {>`MNj  
sSiteURL = value; jBRPR R0  
} 1X&B:_  
vGN3 YcH  
;J=:IEk  
public String getSFilePath() aR)?a;}H  
{ 7>,rvW:]  
return sFilePath; XeU<^ [  
} fA^SD"xf  
)`Ed_F}k  
p+<}Y DMb  
public void setSFilePath(String value) K\^&+7&zVg  
{ t.U{Bu P  
sFilePath = value; Pz`hX$  
} \]8i}E1  
/^ 4"Qv\@/  
VQ<5%+  
public String getSFileName() ?D=8{!R3  
{ gp/YjUH7k8  
return sFileName; n(R_#,Hs  
} sFElD ]|  
m&Sp1=*Ejy  
@q)E=G1<o0  
public void setSFileName(String value) JIV8q HC  
{ XKSX#cia  
sFileName = value; q%S8\bt  
} !<r8~A3!(  
eP= j.$  
tcOnM w  
public int getNSplitter() v}P!HczmMP  
{ &t6Tcy  
return nSplitter; N-QCfDao  
} `~nCbUUee  
=]b9X7}  
gZ`DT  
public void setNSplitter(int nCount) `bqzg  
{ 7$_ :sJ  
nSplitter = nCount; 7I3:u+  
} Jck"Ks  
} kl<g;3  
) ,Npv3(  
?Aw3lH#:  
/* Qlh?iA  
**Utility.java $G3@< BIN  
*/ ^PQM;"  
package NetFox; os**hFPk;1  
O`(U/?   
o#}mkE87  
public class Utility { \ V?I+Gc  
}Vl^EAR  
V6*?$o  
public Utility() 1b[NgOXY=  
{ c F=P!2 @  
SQ<f  
KN, 4@4  
} jY+Do:#/wO  
4J8Dh;a`  
//线程睡眠 5/(sjMB  
public static void sleep(int nSecond) a_%>CD${t  
{ Q>%E`h  
try{ o9+Q{|r  
Thread.sleep(nSecond); WZK :.y  
} }`]]b+_b>@  
catch(Exception e) #Fzb8Yo  
{ (9'be\  
e.printStackTrace (); QgZJ`G--  
} vJThU$s-  
} vZk9gGjk  
`^e*T'UPl  
//日志 C P&o%Uc*  
public static void log(String sMsg) )_Iz>)  
{ {aIZFe}B  
System.err.println(sMsg); 3'^S3W%  
} ?i%nMlcc  
b9#m m  
JV%nH! Fs  
public static void log(int sMsg) }.t^D|  
{ ^O \q3HA_4  
System.err.println(sMsg); :D4];d>1  
} 8]]@S"ZM,\  
} 5Pqt_ZWy  
' &N20w  
cNeiD@t3V&  
/* KBj@V6Q  
**TestMethod.java y#e ?iE@  
*/ !ew6 n I  
package NetFox; 2Pz5f  
D6:DrA:  
kQ[Jo%YT?E  
public class TestMethod { 2-7Z(7G{ F  
&Ea"hd  
WL/5 oj  
public TestMethod() R#LGFXUj  
{ ///xx/weblogic60b2_win.exe g-|Kyhr?=  
try{ 4 +I 3+a"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =h7[E./U1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |?yE^$a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oN ;-M-(  
fileFetch.start(); pU@YiwP"]x  
} L6x B`E9  
catch(Exception e){e.printStackTrace ();} AoU_;B\b%  
q#m!/wod  
:mn(0 R~  
} pJocI_v9  
->3uOF!q  
RUqO!s~#rY  
public static void main(String[] args) KG-y)qXu  
{ ph+M3q(z  
new TestMethod();  h,~tXj  
} $$\V 2%v  
} ;Rs.rl>;t/  
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