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http断点续传简单实现(java)

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/* 1wW8D>f]K  
**SiteFileFetch.java "e69aAA,  
*/ ]-bA{@tP.  
package NetFox; j_L 'Ztu3  
import java.io.*; ivb&J4?y  
import java.net.*;  fv5'Bl  
-=&r}/&  
hWJ\dwF  
public class SiteFileFetch extends Thread { dFjB &#Tl  
d}EGI  
2Y(P hw2%  
SiteInfoBean siteInfoBean = null; //文件信息Bean 38L8AJqD  
long[] nStartPos; //开始位置 `ihlKFX  
long[] nEndPos; //结束位置 eZ[CqUJ&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ecA:y!N  
long nFileLength; //文件长度 B0?E$8a  
boolean bFirst = true; //是否第一次取文件 2IFri|;-eb  
boolean bStop = false; //停止标志 mEa\0oPGB  
File tmpFile; //文件下载的临时信息 5,:>.LRA  
DataOutputStream output; //输出到文件的输出流 MG*#-<OV.  
]ctUl #j  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) L~"~C(g  
public SiteFileFetch(SiteInfoBean bean) throws IOException S`8 h]vX  
{ -N<s =  
siteInfoBean = bean; x>A(016:C  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )-xx$0mL-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); zy(sekX;  
if(tmpFile.exists ()) H1yl88K  
{ |g;hXr#~  
bFirst = false; &{!FE`ZC_  
read_nPos(); 4`o_r%   
} w,SOvbAxX2  
else u> XCE|D*  
{ EoD;'+d  
nStartPos = new long[bean.getNSplitter()]; ?[hIv6c  
nEndPos = new long[bean.getNSplitter()]; cgNK67"(  
} !X$e;V"HX  
J(ZYoJ  
1\z5[ _  
0UB)FK ,9  
} 8L`J](y  
7;:R\d6iL  
=H%c/Jty  
public void run() sWX iY  
{ _Jx.?8  
//获得文件长度 Y #E/"x%+  
//分割文件 )cJ9YKKy  
//实例FileSplitterFetch (2RZc].M~  
//启动FileSplitterFetch线程 Qh<_/X?  
//等待子线程返回 ?){V7<'?y  
try{ nsIx5UA_n  
if(bFirst) 8iaP(*J  
{ S@* lI2  
nFileLength = getFileSize(); .|^L\L(!  
if(nFileLength == -1) 87l(a,#J  
{ w[}5qAI5*f  
System.err.println("File Length is not known!"); 9dn~nnd'n  
} 2kzm(K  
else if(nFileLength == -2) Clr~:2g\  
{ N9QHX  
System.err.println("File is not access!"); |re)]%A?Fu  
} 0Mpc#:a%1  
else F6J,:  
{ Opx"'HC@G  
for(int i=0;i<nStartPos.length;i++) &o%IKB@  
{ nb::,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *WdnP.'Y  
} n`gW&5,,z  
for(int i=0;i<nEndPos.length-1;i++) VN6h:-&iY  
{ +AkAMZ"Mg  
nEndPos = nStartPos[i+1]; 1(t{)Z<  
} P7np -I*  
nEndPos[nEndPos.length-1] = nFileLength; qp$Td<'Y  
} 8WU_d`DF  
} t)o!OEnE  
TK^9!3  
uU_lC5A|  
//启动子线程 w6FtDl$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4UP#~  
for(int i=0;i<nStartPos.length;i++) 1~rZka[s  
{ K;j}qJvsb  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sg0HYb%_E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &(&5ao)5  
nStartPos,nEndPos,i); >F7v'-*{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rUgTJx&ds  
fileSplitterFetch.start(); kD1[6cJ!=.  
} Z ,4G'[d  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %z1y3I|`[t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); wP:ab  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /DLgE7iU%  
nEndPos = " + nFileLength); EhJpJb[Z  
// fileSplitterFetch[nPos.length-1].start(); BhFyEY(  
h|m>JDxn  
V% -wZL/  
//等待子线程结束 Ib V 7}  
//int count = 0; SA3!a.*c  
//是否结束while循环 !.\-l2f  
boolean breakWhile = false; .zDm{_'  
Vm6 0aXm_  
]CL t Km  
while(!bStop) xi3  
{ )Pj8{.t4  
write_nPos(); iH&BhbRu_  
Utility.sleep(500); P[q`{TdV  
breakWhile = true; L`"B;a&  
d9bc>5%-F  
EGD&/%aC  
for(int i=0;i<nStartPos.length;i++) U_\3preF  
{ qC|$0  
if(!fileSplitterFetch.bDownOver) *(c><N  
{ P`ZYm  
breakWhile = false; zI$24L9*  
break;  v7Q=  
} y&F0IJ|`@M  
} s01W_P.@R  
if(breakWhile) e3YdHp  
break; s"jNS1B  
)cF1?2  
'5V#sq;Z  
//count++; =A yDVWpE  
//if(count>4) Z#Q)a;RA  
// siteStop(); >wPMJ> 2  
} iD/r8_}  
Adyv>T9  
$d[ -feU  
System.err.println("文件下载结束!"); Gd= l{~  
} >%PPp.R  
catch(Exception e){e.printStackTrace ();} ?:8wDV  
} OI0tgkG  
LEM^8G]O  
kVG]zt2  
//获得文件长度 _mi(:s(  
public long getFileSize() >mWu+Nn:  
{ ohy?l  
int nFileLength = -1; Vv]81y15Q;  
try{ }'o[6#_*X  
URL url = new URL(siteInfoBean.getSSiteURL()); #c2InwZV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZJ|@^^GcL  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xy;!Q`h(  
[u=DAk?8  
m{ya%F  
int responseCode=httpConnection.getResponseCode(); fUJ\W"qya  
if(responseCode>=400) $1(FN+ M b  
{ t G{?  
processErrorCode(responseCode); I{V1Le4?  
return -2; //-2 represent access is error 1.5lJ:[G  
} qL\*rYe<  
cuw3}4m%  
&dC #nw  
String sHeader; s\-^vj3  
"eH~/6A  
^edg@fp  
for(int i=1;;i++) iN}BMd.U  
{ l5jW`cl1  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); T21SuM  
//Utility.log(in.readLine()); rCmxv7" a}  
sHeader=httpConnection.getHeaderFieldKey(i); BBg&ZIYEh  
if(sHeader!=null) ;[_w&"[6a  
{ 9t$%Tc#Z  
if(sHeader.equals("Content-Length")) I)-u)P?2x  
{ <IF\;,.c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >%"Q]p  
break; mndUQN_Gb  
} Oc]&1>M  
} \E'Nk$V3  
else aE_)iE|  
break;  MRB>(}  
} lRn6Zh  
} Xcq 9*!%o  
catch(IOException e){e.printStackTrace ();} [xXml On!  
catch(Exception e){e.printStackTrace ();} mX8A XWIa  
"~h.u  
t;DZ^Z"{  
Utility.log(nFileLength); 7eh|5e$@  
ifu "e_^  
n\2VrUQ)M  
return nFileLength; tPS.r.0#^  
} YkcX#>,  
Sa&~\!0t  
O=1uF  
//保存下载信息(文件指针位置) }lgqRg)F9[  
private void write_nPos() b'$j* N  
{ JlsRP  
try{ A a2*f[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %J `;  
output.writeInt(nStartPos.length); 4/{Io &|  
for(int i=0;i<nStartPos.length;i++) j$*]'s&_hZ  
{ 'JEZ;9}  
// output.writeLong(nPos); +q]  
output.writeLong(fileSplitterFetch.nStartPos); VI%879Z\e  
output.writeLong(fileSplitterFetch.nEndPos); >GiM?*cC  
} z[Kxy1,  
output.close(); x5m .MQ J  
} ?lb1K'(  
catch(IOException e){e.printStackTrace ();} Jkt L|u:k  
catch(Exception e){e.printStackTrace ();} I}Z[F,}*J  
} z9$x9u  
,{c9Lv%@J  
1h\:Lj  
//读取保存的下载信息(文件指针位置) RR:m <9l  
private void read_nPos() }H{{@RU  
{ M[_~7~4  
try{ 9AJ!7J#v"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K0]'v>AWr  
int nCount = input.readInt(); 4j!MjlG$  
nStartPos = new long[nCount]; dUn8Xqj1  
nEndPos = new long[nCount]; `QR2!W70o3  
for(int i=0;i<nStartPos.length;i++) 8Es]WR5 ^  
{ BzA(yCu$:  
nStartPos = input.readLong(); >qx~m>2|8]  
nEndPos = input.readLong(); w\_NrsO!x  
} .c"UlOZ&w^  
input.close(); UL[4sv6\9  
} |Xd[%W)  
catch(IOException e){e.printStackTrace ();}  ~u8}s4  
catch(Exception e){e.printStackTrace ();} $X9Ban]  
} @DkPJla&  
CBSJY&:K  
mo#4jtCE  
private void processErrorCode(int nErrorCode) ;FZ\PxN  
{ Sct-,K%i  
System.err.println("Error Code : " + nErrorCode); ru(Xeojv#  
} c ~YD|l  
{<~XwJ.  
p`1d'n[  
//停止文件下载 %8$JL=c  
public void siteStop() )gR14a  
{ uA!T@>vl  
bStop = true; 5vbnO]8  
for(int i=0;i<nStartPos.length;i++) I2j;9Qcz  
fileSplitterFetch.splitterStop(); '[Oi_gE.  
=]xNpX)  
 2WE   
} PBn(k>=+  
} V.Xz n  
//负责部分文件的抓取 8)"KPr63M  
**FileSplitterFetch.java ,l; &Tb=k  
*/ J-?\,N1R7  
package NetFox; dhK$ XG  
bHS2;K~  
)r?i^D&4  
import java.io.*; tsfOPth$*  
import java.net.*; {k?Y :  
).oqlA!  
a' #-%!]  
public class FileSplitterFetch extends Thread { (m04Z2#  
 N%r}0  
c_ygwO3.Q  
String sURL; //File URL n#J$=@  
long nStartPos; //File Snippet Start Position Vg \-^$  
long nEndPos; //File Snippet End Position ` V^#Sb  
int nThreadID; //Thread's ID "mPa >`?  
boolean bDownOver = false; //Downing is over RX2= iO"  
boolean bStop = false; //Stop identical 3sp*.dk  
FileAccessI fileAccessI = null; //File Access interface w,}}mC)\*  
$d8A_CUU  
)&dhE^ O  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [0&Lvx  
{ C4 Wdt  
this.sURL = sURL; r]HLO'<]  
this.nStartPos = nStart; y'@l,MN{  
this.nEndPos = nEnd; mu{%%b7|^  
nThreadID = id; ^ w&TTo(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @{CpC  
} t91CxZQ^s  
&PgdCijGq;  
--^D)n  
public void run() 4tuEC-oh  
{ .9^;? Ts  
while(nStartPos < nEndPos && !bStop) @tj0Ir v  
{ jQ^Ib]"K  
@nT8[v  
6wu/6DO   
try{ !k s<VJh  
URL url = new URL(sURL); <=7)t.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O,OGq0c  
httpConnection.setRequestProperty("User-Agent","NetFox");  +;!w;t  
String sProperty = "bytes="+nStartPos+"-"; =OHDp7GXO>  
httpConnection.setRequestProperty("RANGE",sProperty); %@xYg{  
Utility.log(sProperty); F Q k;  
n9J>yud|  
>{??/fBd-  
InputStream input = httpConnection.getInputStream(); zp9 ?Ia  
//logResponseHead(httpConnection); EV(/@kN2  
7>~iS@7GV  
b,`\"'1  
byte[] b = new byte[1024]; 4dok/ +Ec  
int nRead; MnS"M[y3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _0f[.vN  
{ Z*QRdB%,  
nStartPos += fileAccessI.write(b,0,nRead);  y]+A7|  
//if(nThreadID == 1) &%bX&;ECzf  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d{trO;%#f  
} <qy+@t  
$_ i41f[  
lz*2wGI9  
Utility.log("Thread " + nThreadID + " is over!"); 8xv\Zj+  
bDownOver = true; ~k%\ LZ3s  
//nPos = fileAccessI.write (b,0,nRead); \mDm *UuG  
} V& nN/CF  
catch(Exception e){e.printStackTrace ();} 4HHf3j!5  
} l^"G\ZVI  
} S-H3UND"  
h P1|l  
*o#`lH  
//打印回应的头信息 19vD(KC<  
public void logResponseHead(HttpURLConnection con) Zk[#B UA  
{ :h3JDQe:.  
for(int i=1;;i++) L!G3u/  
{ xle29:?l  
String header=con.getHeaderFieldKey(i); {HU48v"W  
if(header!=null) 9e5UTJ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); b2Hpuej  
Utility.log(header+" : "+con.getHeaderField(header)); 5 9vGLN!L  
else pi{ahuI#_o  
break; o (zg_!P  
} 8HOmWQS  
} ]5\vYk  
Pla EI p  
pDLo`F}A  
public void splitterStop() t]ZSo-  
{ 7ou^wt+%  
bStop = true; $3ILVT  
} `jHGNi  
3C2 >   
qrkT7f  
} 8\9EDgT  
;GAYcVB  
K0\WN"ua;  
/* rBf?kDt6l  
**FileAccess.java )3AT=b  
*//文件访问(定位,写) hA8 zXk/'8  
package NetFox; !iw 'tHhR  
import java.io.*; Q  [{vU  
7E95"B&w  
bv/b<N@4?$  
public class FileAccessI implements Serializable{ 1GdD  
W<Lrfo&=Y]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '}u31V"SS  
RandomAccessFile oSavedFile; g&>Hy!v,  
long nPos; (=j!P*  
!UTJ) &  
l 5FQ!>IM  
public FileAccessI() throws IOException 6{'6_4;Fv(  
{ tOw 0(-:iq  
this("",0); M lFvDy  
}  D;]%  
`?x$J 6p  
)^TQedF  
public FileAccessI(String sName,long nPos) throws IOException 9f\8oJQ  
{ kP$g l|  
oSavedFile = new RandomAccessFile(sName,"rw"); YkX=n{^  
this.nPos = nPos; d]E vC>  
oSavedFile.seek(nPos); w>u Z$/  
} b U NYTF{  
D OeKW  
fXe-U='  
public synchronized int write(byte[] b,int nStart,int nLen) ^A`(  
{ {M/c!  
int n = -1; k 5D'RD  
try{ 9#ft;c  
oSavedFile.write(b,nStart,nLen); pm\X*t}L  
n = nLen; {R;M`EU>  
} s.'\&B[  
catch(IOException e) x[UO1% _o-  
{ I})t  
e.printStackTrace (); K/`RZ!  
} GDp p`'\  
YS~t d+*  
Aw;vg/#~md  
return n; ?bAFYF0!I  
} :-La $I>  
&pjV4m|j<  
Z4ioXl  
} mndl~/  
@BUqQ9q:  
*`Xx_   
/* vN:[  
**SiteInfoBean.java +wozjjc  
*/ ?i2Wst  
package NetFox; 4UjE*Aq  
3]n@c?lw  
n~u3  
public class SiteInfoBean { m\M+pjz  
Uy5!H1u  
+\GZ(!~  
private String sSiteURL; //Site's URL ,,%:vK+V  
private String sFilePath; //Saved File's Path 2 BX GVo  
private String sFileName; //Saved File's Name c[_^bs>k  
private int nSplitter; //Count of Splited Downloading File `(/saq*  
8sIA;r%S  
<3=qLm  
public SiteInfoBean() kN |5 J  
{//nSplitter的缺省值为5 5}bZs` C  
//default value of nSplitter is 5 nVn|$ "r  
this("","","",5); =yX&p:-&  
} V!77YFen %  
F4E3c4 81  
yISQYvSN  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |W*@}D  
{ L3GC[$S  
sSiteURL= sURL; hr4ye`c j  
sFilePath = sPath; b>= Wq  
sFileName = sName; {XD/8m(hN|  
this.nSplitter = nSpiltter; ct}%Mdg  
KU|BT .o8  
dG-or  
} yvd `nV  
!3I(4?G,  
/8>0; bX+  
public String getSSiteURL() poQdI?ed,  
{ YYE8/\+B.  
return sSiteURL; Cb{A:\>Q{  
} +an^e'  
]oeuIRyQ  
u-QO>3oY6  
public void setSSiteURL(String value) )?B~64N,+  
{ b-BM"~N'  
sSiteURL = value; _+\:OB[Y  
} f(6UL31  
Xqg.kX  
:'y{dbKp"  
public String getSFilePath() vS$oT]-hKE  
{ 97Zk P=Cq  
return sFilePath; 3WCqKXJ7  
} m0|Ae@g~3  
g=xv+e  
,2,SG/BB  
public void setSFilePath(String value) qE0FgqRB  
{ #d Z/UM(u  
sFilePath = value; \5Vp6^  
} T9z4W]T  
my ;  
_{e&@ d  
public String getSFileName() =a)iVXSB]  
{ crd|2bjp+  
return sFileName; w%3Fg~Up  
} ~V2ajM1Z&O  
/M^V 2=  
L\b]k,Ksf  
public void setSFileName(String value) -BA"3 S  
{ 731h ~x!u  
sFileName = value; b/sOfQ  
} XogvtK*  
"xvtqi,R  
x.b; +p}=  
public int getNSplitter() H>?:U]  
{ Opv1B2  
return nSplitter; \6 \hnP  
} ;Z ]<S_#-  
e0f":Vct  
rH9uGm-*  
public void setNSplitter(int nCount) w]};0v&\~s  
{ #)GW}U]X  
nSplitter = nCount; ^^G-kg  
} })@tA<+  
} 2)wAFO6u  
&/s~? Iq  
aS,a_b]  
/* i?F[||O"$  
**Utility.java u4:\UC'  
*/ br0u@G  
package NetFox; /61by$E  
~|&="K4,:  
f hQy36i@  
public class Utility { FZiZg;  
* [tc  
(cvh3',  
public Utility() pd d|n2q  
{ %=V"CJ$|  
[UMLx  
On=u#DxQ  
} -b cG[W3  
<eY %sFq,  
//线程睡眠 <B!'3C(P  
public static void sleep(int nSecond) Z<;U:aH?}  
{ `dDa}b  
try{ )s7bJjT0=X  
Thread.sleep(nSecond); *zq.C  
} q xfLfgu^  
catch(Exception e) & g:%*>7P  
{ ]}kI)34/  
e.printStackTrace (); X~lZOVmS  
} czI{qi5N  
} S?L#N  
+0J@y1  
//日志 6 mCq/$  
public static void log(String sMsg) X8Xn\E  
{ MM#i t=u  
System.err.println(sMsg); ,9mgYp2  
} Sk\n;mL:  
p%F8'2)}  
#$FrFU;ZR  
public static void log(int sMsg) Pp+~Cir  
{ FEF"\O|Q  
System.err.println(sMsg); 9JPEj-3`g  
} gE\b 982  
} zsDocR   
(YwalfG {C  
oV9z(!X/  
/* w$j{Hp6m  
**TestMethod.java D+sQPymI  
*/ l&L,7BX  
package NetFox; o'Wz*oY))\  
yHNuU)Ft  
8Atq,GcG  
public class TestMethod { := <0=JE#  
jY/ARBC}H  
^gOww6$<  
public TestMethod() ,[isib3  
{ ///xx/weblogic60b2_win.exe YLOwQj'  
try{ s\gp5MT  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); S/4r\6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); uvnI>gv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); cJDd0(tD!  
fileFetch.start(); ~~nqU pK?v  
} NvJV</l6 A  
catch(Exception e){e.printStackTrace ();} I{ ryD -!  
1u~ MXGF  
f+x ;:  
} ~$<UE}qp  
yK1ie  
>2b`\Q*<  
public static void main(String[] args) PD6_)PXn  
{ j*400  
new TestMethod(); M;jcUX_{  
} gEwd &J  
} sw;|'N$:<  
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