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http断点续传简单实现(java)

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/* 7<:w-  
**SiteFileFetch.java 2RXGY  
*/ et ~gO!1:*  
package NetFox; ta6 WZu  
import java.io.*; z=Vvb  
import java.net.*; w./EJk KI  
c`}X2u]k  
zXf+ieo  
public class SiteFileFetch extends Thread { O}f(h5!k  
@ Q1jH~t  
jh0$:6 `C  
SiteInfoBean siteInfoBean = null; //文件信息Bean +@qk=]3a  
long[] nStartPos; //开始位置 ]D-48o0  
long[] nEndPos; //结束位置 XP;&iZJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 YXg uw7%\  
long nFileLength; //文件长度 M2EN(Y_k0  
boolean bFirst = true; //是否第一次取文件 ?Ru`ma\;  
boolean bStop = false; //停止标志 I2DmM"-|  
File tmpFile; //文件下载的临时信息 aQmL=9  
DataOutputStream output; //输出到文件的输出流 d=KOV;~);  
CGe'z  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) lM1!2d'P  
public SiteFileFetch(SiteInfoBean bean) throws IOException R39R$\  
{ 5)o IPHXw  
siteInfoBean = bean; B:r-')!0$#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "=n8PNV/ c  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); TxCQGzqe  
if(tmpFile.exists ()) eo_T .q  
{ 2M#CJ&  
bFirst = false; Y)*lw  
read_nPos(); ZAH<!@qh  
} O({_x@  
else jgo@~,5R  
{ -9*WQU9R  
nStartPos = new long[bean.getNSplitter()]; l9ihW^  
nEndPos = new long[bean.getNSplitter()]; _Lb& 2 PAG  
} *pD;AU  
`^ _:  
@Kr)$F  
`k| nf9_  
} `s_TY%&_}g  
^Q,/C8qeb  
~+C#c,Nw  
public void run() yrs3`/  
{ X[~CLKH(  
//获得文件长度 g[jZ A[[  
//分割文件 ggTjd"|)  
//实例FileSplitterFetch ncdr/(`  
//启动FileSplitterFetch线程 W7o/  
//等待子线程返回 {|E7N"Qzg  
try{ ,h._iO)I^  
if(bFirst) {LD8ie|x1`  
{ KTEis!w  
nFileLength = getFileSize(); VT7NWT J,  
if(nFileLength == -1) "'#Hh&Us  
{ \-0`%k"&  
System.err.println("File Length is not known!"); rw2|1_AF  
} DS2$w9!  
else if(nFileLength == -2) L>b,}w  
{ "y0 A<-~  
System.err.println("File is not access!"); 9.=#4OH/  
} \IfgL$+  
else (B-9M)  
{ 5w1[KO#K|  
for(int i=0;i<nStartPos.length;i++) ,R =VzP&  
{ ~\G3 l,4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sD3|Qj;  
} xH[yIfHkG@  
for(int i=0;i<nEndPos.length-1;i++) __iyBaX  
{ \^4$}@*]  
nEndPos = nStartPos[i+1]; o?FUVK  
} ( `+Z'Y  
nEndPos[nEndPos.length-1] = nFileLength; xlO2jSSAt  
} SXz([Z{)  
} }aM`Jp-O  
w0Y%}7  
wS0bk<(  
//启动子线程 B-|Zo_7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; UYOn p7R<  
for(int i=0;i<nStartPos.length;i++)  vB*oI~<  
{ 8!6*|!,:?n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), XE*bRTEw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *^Y0}?]qT  
nStartPos,nEndPos,i); 3raA^d3!?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^b %8_?2m  
fileSplitterFetch.start(); gu[dw3L  
}  Vb 9N~v  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RA I&;"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :Qo  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 30E v"  
nEndPos = " + nFileLength); 34Khg  
// fileSplitterFetch[nPos.length-1].start(); +yH~G9u(  
)>5k'1  
u/c3omY"#  
//等待子线程结束 ]Hy PJ  
//int count = 0; ]/Qy1,  
//是否结束while循环 MwqT`;lb  
boolean breakWhile = false; a[g|APZz  
CZRo{2!?U  
Z<<gz[$+p  
while(!bStop) ( v:ek_  
{  ja- ~`  
write_nPos(); b_Jq=Gk`  
Utility.sleep(500); +|YZEC  
breakWhile = true; Q5n : f+  
TF-Ty  
So.P @CCd  
for(int i=0;i<nStartPos.length;i++) mS}x2 &  
{ `j}d=zZ  
if(!fileSplitterFetch.bDownOver) b|o!&9Yyr  
{ TeCpT2!5j  
breakWhile = false; .<^Y E%  
break; /'fDXSdP  
} {WeXURp&nF  
} `lezJ (Xm  
if(breakWhile) 7O{O')o!  
break; ?lN8~Ze  
5qkuK F  
/8t+d.r;/  
//count++; l )*,18n  
//if(count>4) cievC,3*  
// siteStop(); CN~NyJL H  
} PFy;qk  
65#:2,s  
?VP!1O=J  
System.err.println("文件下载结束!"); / &D$kxz  
} \R\@t] >Y  
catch(Exception e){e.printStackTrace ();} L2.`1Aag  
} .`>l.gmi&  
Ij}F<ZgZG  
(e3Gs+;  
//获得文件长度 TTZxkK  
public long getFileSize() F*JvpI[7n  
{ (2bZ]  
int nFileLength = -1; !aw#',r8m  
try{ N^( lUba  
URL url = new URL(siteInfoBean.getSSiteURL()); l()MYuLNV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2, "q_d'V  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,,gLrV k  
vF6*c  
J2< QAX  
int responseCode=httpConnection.getResponseCode(); [ 7Lxt  
if(responseCode>=400) @U3foL2\  
{ k;_KKvQ  
processErrorCode(responseCode); EH*ym#Y  
return -2; //-2 represent access is error zB6u-4^wT  
} ~/jxB)t  
v;]I^Kq  
BT#=Xh  
String sHeader; 4[,B;7  
}#HTO:r  
+}1hU :qW  
for(int i=1;;i++) AOlt,MNpQ  
{ Z\=04[  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j H.Ju|nO  
//Utility.log(in.readLine()); jXY;V3l  
sHeader=httpConnection.getHeaderFieldKey(i); SAG` ^t  
if(sHeader!=null) K+@eH#Cv,(  
{ ]8m_*I!  
if(sHeader.equals("Content-Length")) YP#AB]2\}  
{ O(D5A?tv!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mk%"G=w  
break; S`@6c$y k  
} Ur([L&  
} k'ZUBTRq!  
else 3_\{[_W  
break; 2@3.xG  
} $TA6S+  
} gJ3OK!/  
catch(IOException e){e.printStackTrace ();} jxnQG A  
catch(Exception e){e.printStackTrace ();} En,)}yI  
~i }+P71  
}xf='lE  
Utility.log(nFileLength); nRXSW&V"m  
kUg+I_j6*  
UGmuX:@y76  
return nFileLength; :qAc= IC%  
} =l8!VJa  
833 %H`jQc  
uojh%@.4  
//保存下载信息(文件指针位置) ! nCjA\$  
private void write_nPos() 7O+Ij9+{n  
{ v dH+>l  
try{ jKj=#O  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sArje(5Eo  
output.writeInt(nStartPos.length); (lN;xT`=  
for(int i=0;i<nStartPos.length;i++) p<HTJ0  
{ C,{F0-D  
// output.writeLong(nPos); xA&  
output.writeLong(fileSplitterFetch.nStartPos); Cgz&@@j,]  
output.writeLong(fileSplitterFetch.nEndPos); Z\|u9DO  
} h eE'S/  
output.close(); WjY{rM,K  
} vr{'FMc  
catch(IOException e){e.printStackTrace ();} 5>ADw3z'  
catch(Exception e){e.printStackTrace ();} 0Oc}rRH(C  
} >lraYMc<rZ  
vQK n=  
*U;4t/(  
//读取保存的下载信息(文件指针位置) X`fhln9N  
private void read_nPos() 5@ bc(H  
{ c{mKra  
try{ >P\h,1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A,m4WO_q3  
int nCount = input.readInt(); DHm[8 Qp  
nStartPos = new long[nCount]; ~JwpNJs  
nEndPos = new long[nCount]; Mhe |eD#)  
for(int i=0;i<nStartPos.length;i++) (!ZQ  
{ Ig1lol:;  
nStartPos = input.readLong(); <H5n>3#pH  
nEndPos = input.readLong(); aFRTNu/r  
} 9Qzjqq:"Li  
input.close(); y Y>-MoF/t  
} 1 [Sv  
catch(IOException e){e.printStackTrace ();} YVB% kKv{  
catch(Exception e){e.printStackTrace ();} (px*R~}  
} Sc&)~h}YF  
1z~k1usRK  
/7k.r}6\R  
private void processErrorCode(int nErrorCode) r]k*7PK  
{ Kajkw>z  
System.err.println("Error Code : " + nErrorCode); y)3~]h\a  
} 4? m/*VV  
5Noe/6  
^oQekga\l  
//停止文件下载 Dq/3E-y5  
public void siteStop() 8W~lU~-  
{ O9t=lrYV!  
bStop = true; N@Xg5huO  
for(int i=0;i<nStartPos.length;i++) DeOXM=&z  
fileSplitterFetch.splitterStop(); '8 )Wd"[  
9?uqQ  
:O9P(X*  
} koOyZ>  
} jrm0@K+<IA  
//负责部分文件的抓取 H<`^w)?  
**FileSplitterFetch.java 2X|CuL{]  
*/ m_Mwg  
package NetFox; Z0e-W:&;kF  
O6yP qG*j  
$d'CBsu|<  
import java.io.*; {]&R8?%  
import java.net.*; JAc@S20v\  
.Qd}.EG  
1^aykrnQ>  
public class FileSplitterFetch extends Thread { ;"1/#CY773  
^DBD63 N"  
L~*u4  
String sURL; //File URL 9[z'/ U.Bn  
long nStartPos; //File Snippet Start Position /@&(P#h  
long nEndPos; //File Snippet End Position `$J'UXtGc  
int nThreadID; //Thread's ID /^w"' '  
boolean bDownOver = false; //Downing is over a*Rz<08  
boolean bStop = false; //Stop identical Ns'FH(:  
FileAccessI fileAccessI = null; //File Access interface l <:`~\#  
z>6.[Z(T  
c  Qld$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException u\`/Nhn  
{ ~6p5H}'H1  
this.sURL = sURL; 6 |QTS|!  
this.nStartPos = nStart; /sy-;JDnsu  
this.nEndPos = nEnd; csYy7uzi  
nThreadID = id; r+o_t2_b*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 X*0k>j  
} wi>DZkR  
Y|mW.  
1{^CfamF  
public void run() [!W5}=^H  
{ y'^F,WTM  
while(nStartPos < nEndPos && !bStop) neF8V"-u&  
{ LyIKP$t  
-:MmSeG7gO  
$u:<x  
try{ $nj\\,(g  
URL url = new URL(sURL); V]Sgx00;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >wA+[81[  
httpConnection.setRequestProperty("User-Agent","NetFox"); vruD U#  
String sProperty = "bytes="+nStartPos+"-"; 5`"iq "5Cf  
httpConnection.setRequestProperty("RANGE",sProperty); Qe_+r(3)k  
Utility.log(sProperty); 2zhn`m  
^[#=L4  
L/~D<V  
InputStream input = httpConnection.getInputStream(); mIvnz{_d  
//logResponseHead(httpConnection); mxgqS=`  
jDkm:X}:  
{t&*>ma6)  
byte[] b = new byte[1024]; d [r-k 2  
int nRead; J<rlz5':  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :i.t)ES  
{  m;c3Z-  
nStartPos += fileAccessI.write(b,0,nRead); 6Z Xu,ks}  
//if(nThreadID == 1) x.ba|:5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hqL+_| DW  
} 8yn4}`Nc@  
/N>} 4Ay  
{#N%Bq}  
Utility.log("Thread " + nThreadID + " is over!"); E30Ln_^o  
bDownOver = true; 0*/kGvw`i  
//nPos = fileAccessI.write (b,0,nRead); $%Z3;:<Uf-  
} 8&%Cy'TIz4  
catch(Exception e){e.printStackTrace ();} JRXRi*@  
} Apmw6cc  
} K U $`!h  
/HZv  
E4=qh1d  
//打印回应的头信息 n&$/Q$d&  
public void logResponseHead(HttpURLConnection con) Bhe{L?}0  
{ _B3zRO  
for(int i=1;;i++) FNC[59   
{ 1eHe~p ,  
String header=con.getHeaderFieldKey(i); i3P9sdTD  
if(header!=null) Hs$'0:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~q 7;8<U  
Utility.log(header+" : "+con.getHeaderField(header)); q4/909x=  
else UA0F):  
break; a fx'  
} 4@h;5   
} uaaf9SL?  
?_%u)S*g  
ya.n'X14  
public void splitterStop() xz8G}Ku  
{ FIS "Z(  
bStop = true; l[oe*aYN7  
} Lc|{aN  
P 6.!3%y  
TcJ$[  
} &qKig kLd  
RU|X*3";T  
i'=2Y9S}  
/* ,5{$+  
**FileAccess.java 'C^;OjAg  
*//文件访问(定位,写) p?JQ[K7i  
package NetFox; Z/g]o#  
import java.io.*; >?I/;R.-  
5$%XvM  
/P:EWUf'  
public class FileAccessI implements Serializable{ ^s-25 6iI  
JhP\u3 QE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 h&`y$Jj  
RandomAccessFile oSavedFile; e>AXXUEf  
long nPos; |@wyC0k!  
@^&7$#jq%  
mlB~V3M'G  
public FileAccessI() throws IOException YG`? o  
{ kAo.C Nj7  
this("",0); o_$&XNC_  
} ($8t%jVWJJ  
{[W(a<%bXm  
+rc SL8C  
public FileAccessI(String sName,long nPos) throws IOException y`S o&:1  
{ m*Cu-6&qd  
oSavedFile = new RandomAccessFile(sName,"rw"); QIK 9  
this.nPos = nPos; `N'V#)Pi  
oSavedFile.seek(nPos); ,[l`zp  
} p0VUh!  
#K|9^4jt  
50$W0L$  
public synchronized int write(byte[] b,int nStart,int nLen) )/>A6A:  
{ ~*-qX$gr  
int n = -1; `5l01nOxJ  
try{ T$mbk3P  
oSavedFile.write(b,nStart,nLen); n_23EcSy  
n = nLen; 8:dQ._#v  
} q.W>4 k  
catch(IOException e) p$XKlg&  
{ a <wL#Id  
e.printStackTrace (); {v,)G)obWw  
} -c+]Wm"\  
*yez:qnx  
5k$vlC#[H  
return n; v* ~3Z1  
} suVmg-d  
FFvCi@oT  
*x(Jq?5O7X  
} >2lwWXA  
+>tUz D  
Fr [7  
/* ;gB`YNL  
**SiteInfoBean.java yWb4Ify  
*/ rQr!R$t/[  
package NetFox; (MLhaux-  
bRsTBp;R`I  
tj5giQ3DG)  
public class SiteInfoBean { z7T0u.4Ss  
?9xu{B>6  
y{=>$C[  
private String sSiteURL; //Site's URL ZA820A>2!  
private String sFilePath; //Saved File's Path |5MbAqjzC  
private String sFileName; //Saved File's Name `^6 ,kI-c  
private int nSplitter; //Count of Splited Downloading File ~ap2m  
<Ef[c@3  
h-QLV[^  
public SiteInfoBean() :Li/=>R^  
{//nSplitter的缺省值为5 {vVTv SC  
//default value of nSplitter is 5 : ]II-$/8  
this("","","",5); NX,-;v  
} qLK?%?.N<  
Jp~zX lu  
X.V[0$.;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) L:R<e#kgS  
{ \#Up|u:  
sSiteURL= sURL; DL8x":;  
sFilePath = sPath; @S3f:s0~D  
sFileName = sName; caq} &A]C  
this.nSplitter = nSpiltter; `JURQ:l)3^  
Nneo{j  
;rHO&(h-  
} DBgMC"_   
^jSsa  
bF-"tm  
public String getSSiteURL() VaLs`q&3>  
{ E6A /SVp  
return sSiteURL; ;[ 'a  
} MesRa(  
,o#kRWRG  
|i7a@'0)  
public void setSSiteURL(String value) iiC!|`k"  
{ D4u% 6R|F  
sSiteURL = value; A :e;k{J  
} h~} .G{"  
l#qv 5f  
^@6q  
public String getSFilePath() PK2~fJB  
{ QP(BZJC  
return sFilePath; l67Jl"v  
} diT=x52  
cgT  
s0"e'  
public void setSFilePath(String value) u{e-G&]^;  
{ \>Zvev!s  
sFilePath = value; @N.jB#nEb  
} >U!*y4  
5M_Wj*a}7  
l=m(mf?QBg  
public String getSFileName() lB;FUck9  
{ &^.57]  
return sFileName; z\!K<d"Xv  
} X[3}?,aqL  
Ip *g'  
wdas1  
public void setSFileName(String value) 3HC  
{ CA s>AXbs  
sFileName = value; ; H0{CkH  
} ko\):DN  
5Av=3[kh"%  
:k=mzO<&  
public int getNSplitter() @{HrJ/4%:&  
{ aUopNmN  
return nSplitter; vqdX^m^PY  
} AC- )BM';  
]0j9>s2|Z  
Z;DCI-Wg  
public void setNSplitter(int nCount) dJk9@u  
{ ,!QV>=  
nSplitter = nCount; ;0%OB*lcgE  
}  iThSt72  
} 83Ou9E!W  
zGo|JF  
K\?]$dK5  
/* Bi%x`4Lf  
**Utility.java 1NLg _UBOK  
*/ `ldz`yu6++  
package NetFox; Me3dpF  
2DDsWJ;  
a[!%L d  
public class Utility { 7(a2L&k^  
S ZU \i*  
0y#Ih {L  
public Utility() tT%/r,  
{ o^p  
M[]A2'fS  
5"KlRuv%  
} 2umv|]n+l|  
#1nJ(-D+  
//线程睡眠 6p;m\  
public static void sleep(int nSecond) ] ZoPQUS?  
{ t#E}NR  
try{ eVh - _  
Thread.sleep(nSecond); Sus;(3EX  
} bZwnaM4"F  
catch(Exception e) ~l E _L1-c  
{ b{7E;KyY,  
e.printStackTrace (); IVxWxM*N<  
} V|D] M{O  
} 7Ke&0eAw  
Jf;?XP]z  
//日志 ){;02^tX  
public static void log(String sMsg) }?8uH/+ZA  
{ Fj p.T;  
System.err.println(sMsg); JCniN";r[  
} 9WG{p[  
vIGw6BJI  
(8a#\Y[b  
public static void log(int sMsg) pbXi9|bI  
{ aptY6lGv-|  
System.err.println(sMsg); tOl e>]  
} u{H?4|'(  
} !  NV#U  
kSncZ0K{  
j Ch=@<9  
/* Q4]4@96Aj  
**TestMethod.java kLSrj\6I[  
*/ ?)4?V\$  
package NetFox; y(jg#7)  
^ZRYRA  
cQN sL  
public class TestMethod { ]2SI!Ai7  
/B3R1kNf|  
^C)n$L>C0  
public TestMethod() '-$XX%TOAc  
{ ///xx/weblogic60b2_win.exe g=@_Z"  
try{ >pL2*O^{9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YPDf Y<?v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); v6(E3)J7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 256LHY|6  
fileFetch.start(); ~l[r a  
} uq3{h B#  
catch(Exception e){e.printStackTrace ();} mB'3N;~  
jdA ]2]  
sy* y\5yJ  
} \K2*Q&>  
o89( h!  
z9/G4^qF  
public static void main(String[] args) qQ[b VD\*  
{ 3Hi+Z}8  
new TestMethod(); ] ,etZ%z&  
} C)-^<  
} \*vHB`.,ey  
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