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http断点续传简单实现(java)

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/* &m3lXl  
**SiteFileFetch.java kM 6 Qp  
*/ NbobliC=  
package NetFox; |)&%A%m  
import java.io.*; GyIV Hby  
import java.net.*; #c J@uqR  
7$b1<.WX  
H\ %7%  
public class SiteFileFetch extends Thread { 6863xOv{T  
wY#E?,  
R-:2HRaA  
SiteInfoBean siteInfoBean = null; //文件信息Bean ?[AD=rUC  
long[] nStartPos; //开始位置 0sqFF[i  
long[] nEndPos; //结束位置 >z03{=sAN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]]mJ']l  
long nFileLength; //文件长度 qM`}{ /i  
boolean bFirst = true; //是否第一次取文件 x:;kSh  
boolean bStop = false; //停止标志 Q8NX)R  
File tmpFile; //文件下载的临时信息 e(sk[guvX  
DataOutputStream output; //输出到文件的输出流 bOB \--:]  
}EPY^VIw  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) [GR; ?R5  
public SiteFileFetch(SiteInfoBean bean) throws IOException _w{Qtj~s|  
{ $ `c:&  
siteInfoBean = bean; @F eTz[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "[k3kAm  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #R"*c hLV  
if(tmpFile.exists ()) p?!/+  
{ x Ar\gu  
bFirst = false; 8m MQ[#0:}  
read_nPos(); 3mgD(,(^  
} = &]L00u.  
else H)?z #x  
{ Wri<h:1  
nStartPos = new long[bean.getNSplitter()]; b sX[UF  
nEndPos = new long[bean.getNSplitter()]; pkzaNY/q  
} DrR@n~  
ZH8,K Y"  
?}0,o.  
|N2#ItBbW  
} Za9qjBH   
tYS06P^<  
KHme&yMq  
public void run() ]`K2 N  
{ vgPCQO([  
//获得文件长度 sT)CxOV  
//分割文件 JI}'dU>*U:  
//实例FileSplitterFetch 3$ pX  
//启动FileSplitterFetch线程 NOva'qk  
//等待子线程返回 j_AACq {.  
try{ UVP vOtZj  
if(bFirst) UfGkTwoo=  
{ 29Ki uP  
nFileLength = getFileSize(); XwmL.Gg:]7  
if(nFileLength == -1) [~HN<>L@C  
{ q 1,~  
System.err.println("File Length is not known!"); <YY14p  
} #a6iuO0I  
else if(nFileLength == -2) $mILoy B,  
{ SU0 hma8  
System.err.println("File is not access!"); ! mHO$bQ"  
} CrLrw T  
else 5+'<R8{:,  
{ GJrG~T  
for(int i=0;i<nStartPos.length;i++) C_Dn{  
{ ;+%rw2Z,B  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); r&CiSMS*  
} t0S 1QC+  
for(int i=0;i<nEndPos.length-1;i++) uFE)17E  
{ z_HdISy0  
nEndPos = nStartPos[i+1]; 3w=J'(RU  
} w{KavU5W  
nEndPos[nEndPos.length-1] = nFileLength; Hka2  
} L,\Iasv  
} \hXDO_U  
KoT\pY^7\  
{ FkF  
//启动子线程 ^W ^OfY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Y4-t7UlS;  
for(int i=0;i<nStartPos.length;i++) 'DR!9De  
{ *w&e\i|7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;u JMG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7! Nsm  
nStartPos,nEndPos,i); It(_v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #"!<W0  
fileSplitterFetch.start(); TH;hO).u  
} TOt dUO  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), & 21%zPm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ZVBXx\{s  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", L0,'mS  
nEndPos = " + nFileLength); 2G7Wi!J  
// fileSplitterFetch[nPos.length-1].start(); COlqcq'qAu  
>Tgv11[  
ll^#JpT[S  
//等待子线程结束 <I?Zk80  
//int count = 0; -RwE%  cr  
//是否结束while循环 fC`&g~yK'  
boolean breakWhile = false; c{|p.hd  
dV_G1'  
]^E?;1$f?  
while(!bStop) la!~\wpa  
{ _>+Ld6.T6  
write_nPos(); lxx2H1([  
Utility.sleep(500); RZLq]8pM  
breakWhile = true; 3fj4%P"  
vXs"Dst  
tmq OJ  
for(int i=0;i<nStartPos.length;i++) ?s01@f#  
{ [,Gg^*umS  
if(!fileSplitterFetch.bDownOver) #mdc[.  
{ o!Zb0/AP)  
breakWhile = false; K+eM   
break; y(#e}z:  
} D*jM1w_`  
} pi(m7Ci"  
if(breakWhile) S jqpec8  
break; 9[4xFE?|  
Wr 4,YQM  
XFl 6M~ c  
//count++; }bxs]?OW>  
//if(count>4) dO'(2J8  
// siteStop(); {: /}NpA$  
} Txu/{ M,  
aE8VZ8tvq  
Dt@SqX:~Ee  
System.err.println("文件下载结束!"); Nn6%9PX_)  
} kiEa<-]  
catch(Exception e){e.printStackTrace ();} w )f#V s  
} :#Wd~~d  
*dQSw)R  
5pX6t  
//获得文件长度 f*Hr^b}`8  
public long getFileSize() z{ dEC %  
{ &C}*w2]0S  
int nFileLength = -1; =_CzH(=f#  
try{ rq{$,/6.  
URL url = new URL(siteInfoBean.getSSiteURL()); - ).C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )0`C@um  
httpConnection.setRequestProperty("User-Agent","NetFox"); 81F9uM0  
vM={V$D&  
yi[x}ffdE  
int responseCode=httpConnection.getResponseCode(); Rq-ZL{LR7  
if(responseCode>=400) -"x$ZnHU  
{ ]Wup/o  
processErrorCode(responseCode); W/N7vAx X  
return -2; //-2 represent access is error z{q`GwW  
} ).O)p9  
KNl$3nX  
UMi~14& ;  
String sHeader; W?& %x(6M  
tQVVhXQ7  
@7 }W=HB  
for(int i=1;;i++) 7V>M]  
{ X w1*(ffk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *~`(RV  
//Utility.log(in.readLine()); h[ ZN+M  
sHeader=httpConnection.getHeaderFieldKey(i); i8p6Xht  
if(sHeader!=null) jXJyc'm7  
{ e-;}366}  
if(sHeader.equals("Content-Length")) JF]JOI6.e  
{ sO Y:e/_F  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); l/D} X  
break; ;uW FHc5@B  
} }p V:M{Nu&  
} /r 5eWR1G  
else +T ?NH9  
break; 'u658Tj  
} Om&Dw |xG8  
} ~DWl s.  
catch(IOException e){e.printStackTrace ();} vO=fP_  
catch(Exception e){e.printStackTrace ();} cQ|NJ_F{1  
4-w{BZuS  
ZCw]m#lS  
Utility.log(nFileLength); e20-h3h+  
$G>.\t  
]:;&1h3'7  
return nFileLength; }H4RR}g  
} 'w/hw'F6  
]9-\~Mwh  
2oW"'43X  
//保存下载信息(文件指针位置) XW9!p.*.U  
private void write_nPos() ,4 rPg]r@  
{ }Jw,>}  
try{ zs;JJk^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )u">it+  
output.writeInt(nStartPos.length); *hrd5na  
for(int i=0;i<nStartPos.length;i++) V&i;\9  
{ sLFl!jX  
// output.writeLong(nPos); Xj*Wu_  
output.writeLong(fileSplitterFetch.nStartPos); hZ3bVi)L\  
output.writeLong(fileSplitterFetch.nEndPos); E`q_bn  
} #$vEGY}1  
output.close(); ,Q B<7a+I  
} G3]4A&h9v~  
catch(IOException e){e.printStackTrace ();} E7hhew  
catch(Exception e){e.printStackTrace ();} rNM;ZPF#  
} ?%86/N>  
w!CNRtM:~  
6zkaOA46V  
//读取保存的下载信息(文件指针位置) B!yr!DWv  
private void read_nPos() 8MBAtVmy  
{ `/g UV  
try{ ^aQ"E9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g}i61(  
int nCount = input.readInt(); Ru XC(qcq  
nStartPos = new long[nCount]; =;k|*Ny  
nEndPos = new long[nCount]; neh(<>  
for(int i=0;i<nStartPos.length;i++) "b[5]Y{ U  
{ l, wp4 Ll  
nStartPos = input.readLong(); 5f/`Q   
nEndPos = input.readLong(); l2d{ 73h  
} l0] EX>"E  
input.close(); 4 :=]<sc,  
} wzaV;ac4K  
catch(IOException e){e.printStackTrace ();} ,Q,^3*HX9}  
catch(Exception e){e.printStackTrace ();} Q?T]MUY(L  
} VpUAeWb  
&zhAh1m  
8fb'yjIC  
private void processErrorCode(int nErrorCode) >7r!~+B"9'  
{ ,[Fb[#Qqb  
System.err.println("Error Code : " + nErrorCode); O f#:  
} u>$t'  
X 8|EHb<  
%SI'BJ  
//停止文件下载 `6YN3XS  
public void siteStop() K^$=dLp  
{ ':W[A  
bStop = true; HDKbF/  
for(int i=0;i<nStartPos.length;i++) P4?glh q#  
fileSplitterFetch.splitterStop(); ddo#P%sH'  
7rA;3?p)  
8Y3I0S  
} y]im Z4{/  
} +RXoi2"-q@  
//负责部分文件的抓取 Wm|lSisY  
**FileSplitterFetch.java /bEAK-  
*/ "j-CZ\]U|  
package NetFox; r/sNrB1U"y  
1cGmg1U;  
:LTN!jj  
import java.io.*; nm+s{  
import java.net.*; 9cgU T@a  
ca}2TT&t  
l@\FWWQ  
public class FileSplitterFetch extends Thread { Tr|JYLwF  
*kVV+H<X|b  
b\ PgVBf9  
String sURL; //File URL KgG4*<  
long nStartPos; //File Snippet Start Position 8_tQa^.n\  
long nEndPos; //File Snippet End Position ':}\4j&{E  
int nThreadID; //Thread's ID 2Hdu:"j  
boolean bDownOver = false; //Downing is over ]d`VT)~vje  
boolean bStop = false; //Stop identical !+njS  
FileAccessI fileAccessI = null; //File Access interface DJ%PWlK5  
|'.  
uocGbi:V';  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException kl,3IKHa  
{ s7EinI{^  
this.sURL = sURL; L(o15  
this.nStartPos = nStart; e*!kZAf  
this.nEndPos = nEnd; V,9cl,z+  
nThreadID = id; 3[&Cg  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4sM.C9W  
} h1{3njdr  
~v83pu1!2s  
]HdCt3X  
public void run() qa6,z.mQ  
{ Jl<2>@  
while(nStartPos < nEndPos && !bStop) 5coZ|O&f8  
{ rH>)oThA#  
875od  
zT[!o j7  
try{ smLQS+UE  
URL url = new URL(sURL); *j-aXN/$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &0f,~ /%Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); `-&K~^-cH  
String sProperty = "bytes="+nStartPos+"-"; Df#l8YK#  
httpConnection.setRequestProperty("RANGE",sProperty); I0a<%;JJW  
Utility.log(sProperty); &OBkevg  
Jo}eeJ;k  
vFsLY  
InputStream input = httpConnection.getInputStream(); ??T#QQ  
//logResponseHead(httpConnection); ETLD$=iS  
o Rzi>rr  
Fx+*S3==%e  
byte[] b = new byte[1024]; Ev P{p  
int nRead; i?~3*#IpD  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i  LAscb  
{ TPY}C  
nStartPos += fileAccessI.write(b,0,nRead); E"@wek.-  
//if(nThreadID == 1) tl].r|yl  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;>YzEo  
} BB'OCN  
frQ{iUx  
H.2QKws^F  
Utility.log("Thread " + nThreadID + " is over!"); gNhQD*+>{  
bDownOver = true; *#Wdc O `-  
//nPos = fileAccessI.write (b,0,nRead); @A 5?3(e  
} T^v}mWCZ  
catch(Exception e){e.printStackTrace ();} >*n0n!vF  
} 1QJL .  
} BUR*n;V`  
=ruao'A  
9C \Fq-  
//打印回应的头信息 iIogx8[  
public void logResponseHead(HttpURLConnection con) _y3Xb`0a  
{ Lk$B{2^n  
for(int i=1;;i++) wT\49DT"7  
{ j+(I"h3  
String header=con.getHeaderFieldKey(i); _~ &iq1  
if(header!=null) <9%R\_@$H  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); g[t [/TV   
Utility.log(header+" : "+con.getHeaderField(header)); * H9 8Du  
else W];dD$Oqg  
break; m_l[MG\  
} A4ygW:  
} P2*<GjV`S/  
"T"h)L<  
<o= 8 FO  
public void splitterStop() veRm2 LSP  
{ h-D }'R  
bStop = true; +U.I( 83F  
} 7!$^r$t   
-tNUMi'  
F3N6{ysK#  
} d:{O\   
e!r-+.i(  
VQ{fne<  
/* +'@Dz9:>  
**FileAccess.java ^BL"wk  
*//文件访问(定位,写) 2>H24F  
package NetFox; 5BJmA2L  
import java.io.*; e,5C8Q`Z  
/OJ`c`>Q:  
+H2-ZXr  
public class FileAccessI implements Serializable{ 3Le{\}-$.  
w'3iY,_ufC  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -S+zmo8  
RandomAccessFile oSavedFile; {u9}bx'<  
long nPos; D1mfm.9_r^  
2T TdH)  
fg{n(TE"8  
public FileAccessI() throws IOException Rx|;=-8zg  
{ jZ3fKyp#   
this("",0); 0P(!j_2m  
} 1>&]R=  
O,A{3DAe0  
~3S~\0&|  
public FileAccessI(String sName,long nPos) throws IOException -B\HI*u  
{ zkdetrR  
oSavedFile = new RandomAccessFile(sName,"rw");  :#~j:C|  
this.nPos = nPos; + +#5  
oSavedFile.seek(nPos); {GcO3G#FZ  
} ,i@:5X/t  
aoa)BNs  
1&o|TT/  
public synchronized int write(byte[] b,int nStart,int nLen) a+PzI x2  
{ hDq`Z$_+KX  
int n = -1; =iD 3Yt  
try{ 13=.H5  
oSavedFile.write(b,nStart,nLen); ^w06<m  
n = nLen; :<#nTh_@\'  
} B !=F2  
catch(IOException e) uc"P3,M  
{ XEZF{lP  
e.printStackTrace (); .@Dxp]/B}  
} 0k(a VkZ I  
Iy3GE[  
Bn g@-#`/  
return n; ")HFYqP>9  
} {T Ug. %u  
f8.gT49I  
qXjxNrK  
} Q'mM3pq4r  
!o[7wKrXb  
=6|&Jt  
/* VgC2+APg  
**SiteInfoBean.java p`#R<K  
*/ M|(Q0 _8  
package NetFox; td3D=Y  
VEw"  
VD]zz ^  
public class SiteInfoBean { )M//l1  
h@]XBv  
Bv%GJ*>>  
private String sSiteURL; //Site's URL l/ ;  
private String sFilePath; //Saved File's Path "4,?uPi  
private String sFileName; //Saved File's Name ">j j  
private int nSplitter; //Count of Splited Downloading File {Wu$YWE*sx  
SrK<fAkx  
y e? 'Ze  
public SiteInfoBean() c>~*/%+  
{//nSplitter的缺省值为5 ,V:SN~P66+  
//default value of nSplitter is 5 ^J8lBLqe  
this("","","",5); ~Ti'FhN  
} bl(RyA gA  
-701j'q{  
GU8sO@S5#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  !V g`  
{ 4J([6<  
sSiteURL= sURL; pDCeQ6?  
sFilePath = sPath; KX7 >^Bt&k  
sFileName = sName; @w!PaP  
this.nSplitter = nSpiltter; hJ#xB6  
D^3vr2  
e?ly H  
} FA3~|Zg  
EJ:%}HhA  
nl,uuc*;  
public String getSSiteURL() s)Cjc.Qs  
{ e?=^;v%r  
return sSiteURL; K$_0 `>[  
} aC.~&MxFC  
9dUravC7  
t#pS{.I  
public void setSSiteURL(String value) :| 8M`18lZ  
{ {"QNJq#:  
sSiteURL = value; Um-[~-  
} 7 uKY24  
`o8/(`a  
spPNr  
public String getSFilePath() oVfLnI ;  
{ &,CiM0  
return sFilePath; hL;(C) (  
} o,8TDg  
Q_X.rUL0w  
&_|#.  
public void setSFilePath(String value) "#oHYz3D  
{ zZ323pq  
sFilePath = value; YCM]VDx4u1  
} #c?j\Y9nz  
+sUFv)!4  
* 8_wYYH  
public String getSFileName() bNNr]h8y-  
{ fs%.}^kn  
return sFileName; doy`C)xI  
} g($DdKc|g  
}$Tl ?BRpU  
W_8wed:b  
public void setSFileName(String value) {|:;]T"y  
{ 'd$P`Vw:  
sFileName = value; PFne+T!2F  
} 5BKt1%Pg  
iJ3e1w$  
c+$*$|t=v`  
public int getNSplitter() C$D -Pt"+  
{ ?9\EN|O^  
return nSplitter; tL)t"  i  
} lqZ5?BD1  
m?fy^>1  
ZR?yDgL  
public void setNSplitter(int nCount) [^e%@TV>d  
{ ft KTnK.  
nSplitter = nCount; $m1z-i;/  
} j4`0hnqI  
} D9 |n)f  
MET' (m  
;n=.>s*XL'  
/* ` a/%W4  
**Utility.java giIWGa.a+  
*/ ]d0tE?9  
package NetFox; Sf7\;^  
a\E:sPM'>  
| >27 B  
public class Utility { 2Yn <2U/^R  
ve/<=IR Zo  
tlqiXh<  
public Utility() /1Q(b  
{ \6<=$vD  
M .JoHH  
sy"^?th}b  
} u\{ g(li-I  
=L:4i\4  
//线程睡眠 _Khc3Jo  
public static void sleep(int nSecond) Z9 9>5\k  
{ D.Q=]jOs  
try{ M#VE]J  
Thread.sleep(nSecond); /ZPyN<@  
} `~Zs0  
catch(Exception e) U`d5vEhT  
{ 27"%"P.1  
e.printStackTrace (); "C SC  
} B$!)YD;  
} V'T ,4  
O 8u j`G 9  
//日志 -}=%/|\FG  
public static void log(String sMsg) ,:H\E|XeBw  
{ FUOI3  
System.err.println(sMsg); cmg ^J  
} %$ Z7x\_  
T' &I{L33Y  
 @zz1hU  
public static void log(int sMsg) I`LuRl w  
{ $!(pF  
System.err.println(sMsg); Jjv=u   
} M|qteo  
} H {k^S\K  
* %M3PTY\  
O0No'LVu  
/* xp72>*_9&  
**TestMethod.java kg3EY<4i  
*/ ); dT_  
package NetFox; be-~\@  
yo )%J  
R_7 d@FQ1  
public class TestMethod { vIwCJN1C  
:1^R9yWA4  
<U >>ZSi  
public TestMethod() ?)X,0P'  
{ ///xx/weblogic60b2_win.exe )'%$V%9  
try{ [4C:r!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [uls8 "^/j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); u1PaHgi$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &c%g  
fileFetch.start(); g(J&m< I  
} ,@3$X=),E  
catch(Exception e){e.printStackTrace ();} rJ{O(n]j  
,JN8f]a^"g  
yi%-7[*]=  
} RYl>  
cwWodPNm  
lh D,\3/O  
public static void main(String[] args) 9Fm"ei  
{ e9[|!/./5  
new TestMethod(); 5qoSEI-m  
} +H #U~p$  
} F>[,zN  
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