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http断点续传简单实现(java)

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/* [9m3@Yd'  
**SiteFileFetch.java g`XngRb|j  
*/ ;tOs A #  
package NetFox; ^_2c\mw_I  
import java.io.*; CMt<oT6.?  
import java.net.*; $O"ss>8Se  
/9`4f"  
"Xq_N4  
public class SiteFileFetch extends Thread { }w0pi  
r&gvP|W%  
c;l!i-  
SiteInfoBean siteInfoBean = null; //文件信息Bean XiUq#84Q  
long[] nStartPos; //开始位置 UP~28%>X  
long[] nEndPos; //结束位置 w#A)B<Y/"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [!'+}  
long nFileLength; //文件长度 6Yu:v  
boolean bFirst = true; //是否第一次取文件 YpZB-9Krf  
boolean bStop = false; //停止标志 1"h"(dA  
File tmpFile; //文件下载的临时信息 Jw)JV~/0  
DataOutputStream output; //输出到文件的输出流 =pH2V^<<#  
DI C*{aBf  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) BU`X_Z1)  
public SiteFileFetch(SiteInfoBean bean) throws IOException E~!$&9\  
{ 7'0Vb !(  
siteInfoBean = bean; M0V<Ay\%O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y|Iq~Qy~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]aX@(3G1s  
if(tmpFile.exists ()) $:9t(X)H  
{ c*bvZC^6  
bFirst = false; _imuyt".+  
read_nPos(); { bj!]j  
} #<{v~sVp&  
else EVmBLH-a  
{ 6^`iuC5  
nStartPos = new long[bean.getNSplitter()];  X\^nV  
nEndPos = new long[bean.getNSplitter()]; 1I Xtu   
} )Z7Vm2a  
X\^V{v^-  
2]!@)fio`  
xS*UY.>  
} HsY5wC  
-3Kh >b)  
6o't3Peh  
public void run() sSM"~_y\  
{ l;-Ml{}|0  
//获得文件长度 t7=D$ua  
//分割文件 2Tp2{"sB>A  
//实例FileSplitterFetch S?~0)EXj(  
//启动FileSplitterFetch线程 gx&es\  
//等待子线程返回 y|`-)fY  
try{ 1J?v\S$ma`  
if(bFirst) 5EYGA\  
{ .9~j%] q  
nFileLength = getFileSize(); fz'qB-F Y  
if(nFileLength == -1) vDjH $ U  
{ 2 bc&sU)X  
System.err.println("File Length is not known!"); & 3#7>oQ  
} I8xdE(o8+  
else if(nFileLength == -2) m2]N%Y  
{ o[Iu9.zJpy  
System.err.println("File is not access!"); f{BF%;  
} n0(Q/  
else f%G\'q]#F  
{ U]PB)  
for(int i=0;i<nStartPos.length;i++) !~#zd]0x;  
{ pH '_k k  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l\<.*6r  
} fO<40!%9cQ  
for(int i=0;i<nEndPos.length-1;i++) gOF^?M11x  
{ p9v:T1 ?  
nEndPos = nStartPos[i+1]; +nYFLe  
} d$!Q6ux;  
nEndPos[nEndPos.length-1] = nFileLength; 0 R6:3fV6R  
} ?sN{U\  
} U1\7Hcs$  
4 m:h&^`N  
Wjb_H (D  
//启动子线程 R)NSJ-A!2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !%>RHh[  
for(int i=0;i<nStartPos.length;i++) h"FI]jK|}  
{ $1f2'_`8~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lQ 8hY$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), g'.OzD  
nStartPos,nEndPos,i); ;1k& }v&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E&U_1D9=L<  
fileSplitterFetch.start(); >kXscbRL7  
} :i.@d?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "O34 E?ql.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \|=6<ZY:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", oe<i\uX8z  
nEndPos = " + nFileLength); u\\t~<8  
// fileSplitterFetch[nPos.length-1].start(); HP# SR';E  
(W}F\P  
WZQ2Mi<&1'  
//等待子线程结束 AtQ.H-8r  
//int count = 0; $*q|}Tvl#  
//是否结束while循环 9q'9i9/3d  
boolean breakWhile = false; " U\RN  
UtQj<18<  
8dE0y P  
while(!bStop) qTJhYxm  
{ (&}[2pb!  
write_nPos(); C4+DZ<pE  
Utility.sleep(500); gN/<g8  
breakWhile = true; C;W@OS-;  
>|taU8^|G}  
JFT$1^n  
for(int i=0;i<nStartPos.length;i++) }c/p;<  
{ wGyVmC  
if(!fileSplitterFetch.bDownOver) __=53]jGE  
{ 3FBLCD3  
breakWhile = false; !se1W5ke#  
break; &'uP?r9c$  
} ;cMQ 0e  
} '1mk;%  
if(breakWhile) )eZK/>L&  
break; u/=hueR<^  
g p:0Y  
o=rR^Z$G   
//count++; OZ&/&?!XE  
//if(count>4) ~$J ;yo~  
// siteStop(); yqN`R\d  
} c p"K?)  
gUklP(T=u  
K(;qd Ir  
System.err.println("文件下载结束!"); pGs?Y81  
} [)"\Aq  
catch(Exception e){e.printStackTrace ();} }0'LKwIR  
} |]7c&`  
-1Q24jrO-  
Xm#W}Y'  
//获得文件长度 Xg dBLb  
public long getFileSize() /4x\}qvU  
{ Q y qOtRk  
int nFileLength = -1; Kd:l8%+  
try{ %o?)`z9-  
URL url = new URL(siteInfoBean.getSSiteURL()); D Q.4b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A5nggg4  
httpConnection.setRequestProperty("User-Agent","NetFox"); u W]gBhO$O  
<K CI@  
.W{CJh  
int responseCode=httpConnection.getResponseCode(); QAkK5,`vV.  
if(responseCode>=400) |=0vgwd"S  
{ 78l);/E{v  
processErrorCode(responseCode); yCQvo(V[F  
return -2; //-2 represent access is error OAXA<  
} IxbQ6  
o GuAF q  
$;^|]/-  
String sHeader; WARiw[  
s#^0[ Rt  
tVG;A&\,6  
for(int i=1;;i++) i-|N6J  
{ 7 yE\,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [* <x)  
//Utility.log(in.readLine()); S~/2Bw!2  
sHeader=httpConnection.getHeaderFieldKey(i); :E9pdx+  
if(sHeader!=null) /EjXyrn2  
{ coXg]bUKo  
if(sHeader.equals("Content-Length")) ?t 'V5$k\  
{ Im6gWDdq@6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v0 C+DKi  
break; |]G%b[  
} <|r|s  
}  }u8(7  
else Ta\F~$M  
break; u8c@q'_  
} Sr \y1nt  
} ;"M6}5dQ4  
catch(IOException e){e.printStackTrace ();} ~vXbh(MX  
catch(Exception e){e.printStackTrace ();} 8dR `T}  
8&JB_%Gb  
y i$+rPF1  
Utility.log(nFileLength); |enLv12Gm  
x,C8):\t`B  
LK}g<!o(  
return nFileLength; 6Z|h>H5 a  
} 3dN`Q:1R9  
p7QZn.,=u  
/?;'y,(Q  
//保存下载信息(文件指针位置) fXMY.X>f  
private void write_nPos() |OeWM  
{ [q|W*[B:@  
try{ C>|.0:[%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); h(=<-p @  
output.writeInt(nStartPos.length); A:m+v{*`4  
for(int i=0;i<nStartPos.length;i++)  qNJc*@s  
{  SCfp5W7~  
// output.writeLong(nPos); !h #ZbErW  
output.writeLong(fileSplitterFetch.nStartPos); %SC Jmn2  
output.writeLong(fileSplitterFetch.nEndPos); kt6)F&;$  
} r R6}  
output.close(); #LR4%}mg  
} !q+ #JW  
catch(IOException e){e.printStackTrace ();} D('.17  
catch(Exception e){e.printStackTrace ();} 7"!`<5o^  
} 7<su8*?  
#G#gc`S-,  
=\lw.59  
//读取保存的下载信息(文件指针位置) # Wi?I =,  
private void read_nPos() ~61b^L}$  
{ d.? }>jl  
try{ #@oB2%&X?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); VpJKH\)Rt(  
int nCount = input.readInt(); b? o  
nStartPos = new long[nCount]; 3Y Mqp~4  
nEndPos = new long[nCount]; Ba[,9l[  
for(int i=0;i<nStartPos.length;i++) Qs\a&Q=0H  
{ U)G.Bst  
nStartPos = input.readLong(); e*Wk;D&  
nEndPos = input.readLong(); x*H#?.E  
} V;eaQ  
input.close(); Il [~  
} !JXiTI!  
catch(IOException e){e.printStackTrace ();} 1 !_p  
catch(Exception e){e.printStackTrace ();} 1r=cCM  
} ;qaPK2 a8  
:(]fC~G~  
P!]uJ8bi  
private void processErrorCode(int nErrorCode)  ,]EhDW6  
{ Mz&/.A  
System.err.println("Error Code : " + nErrorCode); l:'#pZ4T  
} 0!,uo\`  
/ <)Vd  
KRL.TLgq)  
//停止文件下载 X&WP.n)  
public void siteStop() Z5Lmg  
{ fHd[8{;P:  
bStop = true; %rrA]\C'  
for(int i=0;i<nStartPos.length;i++) HF0G=U}i  
fileSplitterFetch.splitterStop(); l Xa/5QKC  
wF`Y ,@  
|RL#BKC`  
} t.8r~2(?  
} V22z-$cb  
//负责部分文件的抓取 QdgJNT<=H,  
**FileSplitterFetch.java ;mEn@@{  
*/ 4|K\pCw  
package NetFox; <yipy[D  
F ,472H  
>OaD7  
import java.io.*; d@ K-ZMq  
import java.net.*; 4 -.W~C'Q  
WGz)-IB!PE  
zjA]Tr  
public class FileSplitterFetch extends Thread { ]qqgEZ1!Y  
ir<e^a  
"`ftcJUd  
String sURL; //File URL {A/^;X{N^  
long nStartPos; //File Snippet Start Position 8;?4rrS  
long nEndPos; //File Snippet End Position =sk[I0W  
int nThreadID; //Thread's ID ~1+6gG  
boolean bDownOver = false; //Downing is over :\|A.# U  
boolean bStop = false; //Stop identical GqHW.s5  
FileAccessI fileAccessI = null; //File Access interface =dPokLXn  
Kkp dcc  
k7iko{5D  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException |^l_F1+w  
{ -  ]wT  
this.sURL = sURL;  p?f\/  
this.nStartPos = nStart; bVzi^R"  
this.nEndPos = nEnd; }O*`I(  
nThreadID = id; dJgLS^1E  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;~<To9O  
} KFbB}oId  
b;b,t0wS  
ZxNTuGOB:  
public void run() 5;}W=x^$a  
{ Uuy$F  
while(nStartPos < nEndPos && !bStop) 0S4BV%7F  
{ ?Ujg.xo\  
gl+d0<R zw  
ZjmQ  
try{ /-p!|T}w  
URL url = new URL(sURL); K#+?oFo:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 14 & KE3`  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^i%S}VK  
String sProperty = "bytes="+nStartPos+"-"; (|BY<Ac3  
httpConnection.setRequestProperty("RANGE",sProperty); Ip'tB4Mq  
Utility.log(sProperty); ]i#p2?BR  
bq ED5;d'#  
nx'c=gp  
InputStream input = httpConnection.getInputStream(); KZjh<sjX|  
//logResponseHead(httpConnection); ~bZ =]i  
0 cycnOd  
m}'_Poc  
byte[] b = new byte[1024]; g$s;;V/8e  
int nRead; ZHK>0>;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O#U maNj/  
{ ."+lij=56  
nStartPos += fileAccessI.write(b,0,nRead); 8)0]cX  
//if(nThreadID == 1) 0:v !'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n.+'9Fj  
} LH4A!a]  
!uGfS' Vl  
Q7uJ9Y{X  
Utility.log("Thread " + nThreadID + " is over!"); S[K5ofV  
bDownOver = true; p{L;)WTI  
//nPos = fileAccessI.write (b,0,nRead); 1*8;)#%&  
} cp@Fj"  
catch(Exception e){e.printStackTrace ();} 2Xl+}M.:Y  
} j+h+Y|4J  
} `xzKRId0  
B4b'0p  
|H t5a.  
//打印回应的头信息 #zl1#TC{(  
public void logResponseHead(HttpURLConnection con) 0 SSdp<  
{ b11I$b #  
for(int i=1;;i++) K[y")ooE<j  
{ R@K\   
String header=con.getHeaderFieldKey(i); D<J'\mo  
if(header!=null) 8lV:-"+5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t.ulG *  
Utility.log(header+" : "+con.getHeaderField(header)); M>i(p%  
else NTt4sWP!I  
break; i pn-HUrE@  
} DDr\Kv)k(  
} VwI  
#p(c{L!  
t,9+G<)>H  
public void splitterStop() 2V@5:tf  
{ *5PQ>d G  
bStop = true; =v<w29P(g  
} YcA. Bn|as  
%k#+nad  
b23A&1X  
} */e$S[5  
"0!h- bQN  
yF)J7a:U  
/*  zjUQ]  
**FileAccess.java 9Rk(q4.OP  
*//文件访问(定位,写) >.qFhO\1so  
package NetFox; iLnW5yy  
import java.io.*; i?/Q7D<P  
Ln# o:"E  
pX_  
public class FileAccessI implements Serializable{ &`qYe)1Eo  
TAUl{??,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Bb=r?;zjO  
RandomAccessFile oSavedFile; lf`ULY4{  
long nPos; t5E$u(&+'B  
vt5w(}v(  
wG)e8,#  
public FileAccessI() throws IOException a Y)vi$;]  
{ %d+Fq=<  
this("",0); ^dpM2$J  
} w<B S  
'aEK{#en  
TIJH} Ri  
public FileAccessI(String sName,long nPos) throws IOException 1e[?}q]*  
{ x~5,v5R^]  
oSavedFile = new RandomAccessFile(sName,"rw"); qA '^b~  
this.nPos = nPos; V<9L-7X 8  
oSavedFile.seek(nPos); p-"C^=l  
} Qp<*o r@  
"9xJ},:-  
+~V_^-JG&  
public synchronized int write(byte[] b,int nStart,int nLen) ]izHn;+  
{ ) r.Wge  
int n = -1; m^oG9&";  
try{ Ze%S<xT!O  
oSavedFile.write(b,nStart,nLen); K ar!  
n = nLen; p1'q{E+o*  
} vT#R>0@mi  
catch(IOException e) q%G[tXw  
{ B5 /8LEWw  
e.printStackTrace (); "1gIR^S%9  
} Y!j/,FU  
^!B]V>L-  
diNSF-wi,,  
return n; gN}$$vS  
} p|gVIsg[-e  
C1{Q 4(K%  
"S#$:92  
} [,U l  
\Yj_U'2"i  
<p<6!tdO  
/* #om Gj&  
**SiteInfoBean.java M%:\ry4:  
*/ y" H5>  
package NetFox; K_+M?ap_  
iY`[dsT  
#q:j~4)h  
public class SiteInfoBean { +On2R&m  
imADjBR]  
1CJ1-]S(3  
private String sSiteURL; //Site's URL Lf9s'o}.R  
private String sFilePath; //Saved File's Path z2V ->UK)  
private String sFileName; //Saved File's Name NCg("n,jx  
private int nSplitter; //Count of Splited Downloading File 2XyyU}.$  
Bj{J&{  
z>+CMH5L)  
public SiteInfoBean() F lVG,Z  
{//nSplitter的缺省值为5 M5*Ln-qt(a  
//default value of nSplitter is 5 lFuW8G,-f@  
this("","","",5); w)<.v+u.Y  
} )r"R  
15_"U+O(/  
@B0fRG y  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @8\0@[]  
{ v3[ZPc;;  
sSiteURL= sURL; W ~MNst?  
sFilePath = sPath; <>KQ8:  
sFileName = sName; +mG"m hF  
this.nSplitter = nSpiltter; T=w0T-[f  
j 7);N  
W/RB|TMT  
} GF@` ~im  
ug}u>vQ>  
IHW s<U  
public String getSSiteURL() [6K[P3UZx  
{ 4NRj>y  
return sSiteURL; E @r &K  
} Lwtp,.)pR  
I5j|\ /Ht  
R{H8@JLD  
public void setSSiteURL(String value) "$5cKbJ  
{ QX?moW6UW  
sSiteURL = value; r+Sv(KS4i^  
} X r o5~G  
Rex 86!TO  
Bs3&y Eq(  
public String getSFilePath() on hLhrZ  
{ mb_6f:Qh3  
return sFilePath; DIYR8l}x  
} 9Pvv6WyKy  
[#aJ- Uu  
\Dr( /n  
public void setSFilePath(String value) ,W 'P8C  
{ ;<o?JM  
sFilePath = value; @@3 NSKA  
} $2]>{g  
BQ,749^S  
 f^}n#  
public String getSFileName() 4<<eqxI$|  
{ Wf?[GO  
return sFileName; ?W dY{;&  
} :V6t5I'_  
?;w`hA3ei  
\u6.*w5TI  
public void setSFileName(String value) q(46v`u  
{ D @wIbU  
sFileName = value; %Ze7d&  
} WOgkv(5KN  
Nj?Q{ztS  
E i2M~/  
public int getNSplitter() Q4Wz5n1yp7  
{ mxH63$R  
return nSplitter; ) C\/(  
} )`<&~>qp  
`p)U6J  
25 U+L  
public void setNSplitter(int nCount) =^zGn+@z  
{ Fv(FRZ)  
nSplitter = nCount; b5~p:f-&4B  
} i u0'[  
} I(3YXv VN  
Bs '=YK$  
kTzO4s?  
/* [@pumH>  
**Utility.java `S3)uV]I  
*/ QX a2qxTc  
package NetFox; zk@s#_3ct  
x!7!)]h  
mWP&N#vwh  
public class Utility { 6c>:h)?  
<RbsQ^U  
Q"!GdKM  
public Utility() ',D%,N}J  
{ pL*aU=FjQ  
Wj)v,v2&  
RP 6<#tq,  
} )2^r 0(x  
j:8Pcx  
//线程睡眠 k8+U0J_{'  
public static void sleep(int nSecond) C%%gCPI^y  
{ sA+K?_  
try{ +~1FKLu  
Thread.sleep(nSecond); A58P$#)?  
} IW}Wt{'m  
catch(Exception e) @eESKg(,  
{ jW^]N$>  
e.printStackTrace (); . Y!dO@$:  
} 39 pA:3iTd  
} Q7zpu/5?  
#<V5sgq S  
//日志 =|fB":vk  
public static void log(String sMsg) 6B b+f"  
{ roi,?B_8  
System.err.println(sMsg); 7 > _vH]  
} }QCn>LXE  
Jh4pY#aF  
Gy6x.GX  
public static void log(int sMsg) YoK )fh$  
{ 9B>P Qbs  
System.err.println(sMsg); }Q^*Zq9-  
} "2tKh!?Q  
} pI_:3D xe  
XKOPW/  
,CBE&g  
/* J{5p4bkb  
**TestMethod.java }dU!PZ9N)  
*/ SY}"4=M?l  
package NetFox; $ \!OO)  
$&jVEMia  
<|E*aR|M  
public class TestMethod { VTX6_&Hc1g  
bq8h?Q  
QM~~b=P,\  
public TestMethod() _$8:\[J  
{ ///xx/weblogic60b2_win.exe z 63y8  
try{ ra@CouR^c{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @'Pay)P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `0+-:sXZ6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tu ;Pm4q7  
fileFetch.start(); <a+ @4d;  
} B <G,{k  
catch(Exception e){e.printStackTrace ();} p%#'`*<a_  
}P\6}cK  
3".#nN  
} D mky!Cp  
l&Y'5k_R  
rodqa  
public static void main(String[] args) P*ZMbAf.  
{ =L?2[a$2;  
new TestMethod(); ^oE#;aS  
} u2[L^]|  
} d+ [2Sm(7  
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