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http断点续传简单实现(java)

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/* ovd^,?ib  
**SiteFileFetch.java ua`6M  
*/ (Qk&g"I  
package NetFox; K85_>C%g  
import java.io.*; cBifZv*l  
import java.net.*; 1C_'H.q<=  
"xvtqi,R  
L1hD}J'$4  
public class SiteFileFetch extends Thread { PwW^y#96  
g7xbyB o7  
%K h2E2Pe  
SiteInfoBean siteInfoBean = null; //文件信息Bean S3u yn78hI  
long[] nStartPos; //开始位置 qyg*n>nt  
long[] nEndPos; //结束位置  yS[z2:!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 iV?` i  
long nFileLength; //文件长度 h/I@_?k+  
boolean bFirst = true; //是否第一次取文件 ^|wT_k\  
boolean bStop = false; //停止标志 IQ3n@  
File tmpFile; //文件下载的临时信息 umQi  
DataOutputStream output; //输出到文件的输出流 n{dP@_>WS  
v9%nau4  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Zc-#;/b3T  
public SiteFileFetch(SiteInfoBean bean) throws IOException )xB$LJM8  
{ 0iYP  
siteInfoBean = bean; Ovv ny$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); m!<X8d[bD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \n#]%X5c  
if(tmpFile.exists ()) X[V?T>jsM  
{ pT4qPta,2  
bFirst = false; ^vpIZjN  
read_nPos(); * [tc  
} ZB828T3  
else Q[M (Wqg  
{ "H>.':c"+3  
nStartPos = new long[bean.getNSplitter()]; Sv7 i! j  
nEndPos = new long[bean.getNSplitter()]; ?VB#GJ0M9  
} u7HvdLql  
'WK;$XQ  
9b1?W?"  
#(6) ^ (  
} Y}ng_c  
eUt=n)*`  
`gt:gx>a  
public void run() UP\C"\  
{ Yp*,Jp1  
//获得文件长度 ,j y<o+!  
//分割文件 ]}kI)34/  
//实例FileSplitterFetch e^ QVn\<c  
//启动FileSplitterFetch线程 wX ,h< \7  
//等待子线程返回 )!e3.C|V1W  
try{  EZ<80G  
if(bFirst) |xh&p(  
{ SB TPTb  
nFileLength = getFileSize(); Vvyj  
if(nFileLength == -1) pTWg m\h  
{ e 8,{|a  
System.err.println("File Length is not known!"); )\wuesAO  
} 7rcA[)<'  
else if(nFileLength == -2) i'HPRY  
{ NPm;  
System.err.println("File is not access!"); 7:>sc]Z  
} IU|kNBo  
else bhD ~ 4Rz  
{ ["a"x>X&  
for(int i=0;i<nStartPos.length;i++) EUy(T1Cl&&  
{ rfs(#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /Pvk),ca  
} w9f _b3  
for(int i=0;i<nEndPos.length-1;i++) Stxp3\jEn  
{ '.(~  
nEndPos = nStartPos[i+1]; *YtB )6j  
} %X>FVlPm  
nEndPos[nEndPos.length-1] = nFileLength; X4wH/q^  
} zBY~lNB  
} +~Tu0?{Z 0  
mu[Op*)  
N}b^fTq  
//启动子线程 {,?ss$L  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r|GY]9  
for(int i=0;i<nStartPos.length;i++) 6)}B"Qd  
{ K]/Od  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !`&\Lx_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?mx\eX{  
nStartPos,nEndPos,i); +;Cr];b3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M0L&~p_F  
fileSplitterFetch.start(); :et#0!  
} PcC/_+2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $6h*l T<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a460|w6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", icgJ;Q 5  
nEndPos = " + nFileLength); w^q7n  
// fileSplitterFetch[nPos.length-1].start(); 1%~[rnQ  
>&U @f  
G:IP? z]  
//等待子线程结束 #.._c?%4/  
//int count = 0; UDEj[12S  
//是否结束while循环 w0w1PE-V=  
boolean breakWhile = false; 6>`c1 \8f  
'yY>as  
IP3E9z_ L  
while(!bStop) !eI2 r   
{ $q_R?Eay  
write_nPos(); *?t%0){  
Utility.sleep(500); V'DA[{\*  
breakWhile = true; 9Uf j  
9GU]l7C=z  
S`!-Cal`n  
for(int i=0;i<nStartPos.length;i++) (JUZCP/\  
{ upy\gkpnGO  
if(!fileSplitterFetch.bDownOver) x Q4%e[/  
{ :E&g%'1  
breakWhile = false; <S?#@F\"S  
break; -/P\"c  
} 7f{=w, U  
} ~" i0x  
if(breakWhile) U_B(( Z(g  
break; W-efv  
bBc[bc>R  
4_/?:$KO  
//count++; z (?=Iv3  
//if(count>4) 72W s K"  
// siteStop(); P"/G  
} jszK7$]^  
Az;t"  
)wvHGecp*  
System.err.println("文件下载结束!"); iBTYY{-wF  
} sEJC-$   
catch(Exception e){e.printStackTrace ();} 7!WA)@6  
} vw,rF`LjZ  
Jg}K.1Hs  
RTh`ENCKR  
//获得文件长度 ~*A8+@ \R  
public long getFileSize() z`UhB%-?  
{ . mLK`c6  
int nFileLength = -1; 5,-U.B}  
try{ H,nec<Jp  
URL url = new URL(siteInfoBean.getSSiteURL()); y*pUlts<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W\&8au ds  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0j"8@<  
C CBfKp  
I M-L'9  
int responseCode=httpConnection.getResponseCode(); (3J$>Na  
if(responseCode>=400) Szbb_i{_ `  
{ }J">}j]/  
processErrorCode(responseCode); Qham^  
return -2; //-2 represent access is error +t5U.No  
} 26&'X+n&  
&0 >Loja`^  
R}^~^#  
String sHeader; 6f')6X'x  
"#[!/\=?:  
MjlP+; !  
for(int i=1;;i++) Q8!) !r%  
{ $hivlI-7Ko  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4RSHZAJg  
//Utility.log(in.readLine()); b2b^1{@h;v  
sHeader=httpConnection.getHeaderFieldKey(i); e/0<[s*#Q  
if(sHeader!=null) M`rl!Ci#  
{ 91 =OF*w  
if(sHeader.equals("Content-Length")) n2)q}_d  
{ 3s/H2f z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F a'k0/_j  
break; 3;S, 3  
} [0"'T[ok  
} Llr>9(|  
else Vn*tp bz  
break; > ;/l)qk,  
} Zt.'K(]2h  
} Y. ,Kl~  
catch(IOException e){e.printStackTrace ();} xx[9~z=d  
catch(Exception e){e.printStackTrace ();} ZI=%JU(  
"@?? Fw!  
*h}XWBC1q  
Utility.log(nFileLength); $ s9Vrw0Z  
{r@Ty*W} L  
C(00<~JC  
return nFileLength; S30?VG9U0f  
} kS bu]AB  
UrqRx?#  
+=O5YR!{  
//保存下载信息(文件指针位置) 7;KwLT9  
private void write_nPos() zIh ['^3.n  
{ ?OkWe<:4  
try{ c-B cA  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^$b Y,CE  
output.writeInt(nStartPos.length); WZ.@UN,  
for(int i=0;i<nStartPos.length;i++) 1oc3$A  
{ rg^'S1x|  
// output.writeLong(nPos); 8C*c{(4  
output.writeLong(fileSplitterFetch.nStartPos); z^'gx@YD*v  
output.writeLong(fileSplitterFetch.nEndPos); H Z'_r cv  
} 9I&xfvD,  
output.close(); ;7} VBkH  
} eA E`# t  
catch(IOException e){e.printStackTrace ();}  R}O_[  
catch(Exception e){e.printStackTrace ();} ~_/(t'9  
} ibj87K  
e 9;~P}  
hDF@'G8F  
//读取保存的下载信息(文件指针位置) >m$1Xx4#GV  
private void read_nPos() ` @`CG[-9  
{ KV(Q;~8"X  
try{ bbE!qk;hEP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #d6)#:uss  
int nCount = input.readInt(); <0Xf9a8>  
nStartPos = new long[nCount]; k$blEa4  
nEndPos = new long[nCount]; 'uBu6G  
for(int i=0;i<nStartPos.length;i++) 'Gj3:-xqL  
{ YtmrRDQs  
nStartPos = input.readLong(); 8Vr%n2M  
nEndPos = input.readLong(); 2LF/H$] o5  
} ]'&LGA`  
input.close(); {*G9|#[/@  
} Q'=x|K#xj  
catch(IOException e){e.printStackTrace ();} c2l@6<Ww  
catch(Exception e){e.printStackTrace ();} B3 8]~'8  
} "\w 7q  
La`NPY_:>  
-t!~%_WCv  
private void processErrorCode(int nErrorCode) wW>A_{Y  
{ ;U/&I3dzV  
System.err.println("Error Code : " + nErrorCode); "\: `/k3  
} q'T4w!V(V  
|d{PA.@33  
'DP1,7  
//停止文件下载 cr7 }^s  
public void siteStop() _kef 0K6  
{ ]L5@,E4.  
bStop = true; rV` #[d  
for(int i=0;i<nStartPos.length;i++) J,'M4O\S  
fileSplitterFetch.splitterStop(); 'j#*6xD  
A8muQuj]~~  
p|U?86 t  
} fK>L!=Q  
} 9+Np4i@  
//负责部分文件的抓取 Cio 1E-4  
**FileSplitterFetch.java @LF,O}[2J  
*/ f,U.7E  
package NetFox; ;17E(tl  
_>&X\`D   
P) Jgs  
import java.io.*; ` Fa~  
import java.net.*; kMIcK4.MH  
8V'~UzK  
)}Hpi<5N  
public class FileSplitterFetch extends Thread { Vh|*p&  
^UP`%egR  
*7uH-u"5d  
String sURL; //File URL ZF!h<h&,  
long nStartPos; //File Snippet Start Position @a! #G  
long nEndPos; //File Snippet End Position Dj"F\j 1  
int nThreadID; //Thread's ID Wf+cDpK  
boolean bDownOver = false; //Downing is over $0W|26;  
boolean bStop = false; //Stop identical g2+2%6m0  
FileAccessI fileAccessI = null; //File Access interface h79}qU  
yb<fpM  
y8]B:_iU9  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p*XANGA  
{ ROH|PKb7  
this.sURL = sURL; !z\h| wU+  
this.nStartPos = nStart; 8SMxw~9$  
this.nEndPos = nEnd; <$D`Z-6  
nThreadID = id; ?qb}?&1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /2&c$9=1  
} ;YaQB#GK%  
\[;0 KV_  
g_;\iqxL  
public void run() )*u8/U  
{  on4HKeO  
while(nStartPos < nEndPos && !bStop) _P!m%34|  
{ 3/P1!:g9  
=}~hWL  
Na<pwC  
try{ ]=\].% >  
URL url = new URL(sURL); z}.e]|b^H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1y:-N6  
httpConnection.setRequestProperty("User-Agent","NetFox"); Fn wJ+GTu  
String sProperty = "bytes="+nStartPos+"-"; -M\<nx  
httpConnection.setRequestProperty("RANGE",sProperty); l5~os>  
Utility.log(sProperty); ko!)s  
!hm]fh_j  
T~-ycVc  
InputStream input = httpConnection.getInputStream(); irZ])a  
//logResponseHead(httpConnection); ,>:U2%  
%:i7s-0w  
Jx:Y-$  
byte[] b = new byte[1024]; Xu{1".\  
int nRead; t^&Cxh  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) HVRZ[Y<^  
{ 7 W5@TWM  
nStartPos += fileAccessI.write(b,0,nRead); td$E/h=3  
//if(nThreadID == 1) X;$+,&M"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z'Hw  
} yNPVOp*  
e1yt9@k,  
0S"mVZ*P  
Utility.log("Thread " + nThreadID + " is over!"); hDDn,uzpd  
bDownOver = true; dRYqr}!%n  
//nPos = fileAccessI.write (b,0,nRead); 3<Lx&p~%T  
} ~g91Pr   
catch(Exception e){e.printStackTrace ();} /PVk{3  
} PI {bmZ  
} 8]c2r%J  
gb1V~  
}J}-//[A  
//打印回应的头信息 cVv=*81\  
public void logResponseHead(HttpURLConnection con) X0HZH?V+  
{ )$2QZ qX  
for(int i=1;;i++) hPkp;a #  
{ G[PtkPSJ  
String header=con.getHeaderFieldKey(i); #~]zhHI  
if(header!=null) [jQp~&nY  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); x8 2cT21b  
Utility.log(header+" : "+con.getHeaderField(header)); 7sCG^&Y  
else qz_7%c]K[  
break; LE Nq_@$  
} [>I<#_^~  
} /8'NG6"H`  
tAd%#:K  
Wu/]MBM  
public void splitterStop() 5Pc;5 o0C  
{ Qp5VP@t  
bStop = true; ^LnTOdAE  
} 5{WE~8$  
KfEx"94  
/KaZH R.  
} bSlF=jT[S  
)u&|_&g{}J  
n+9=1Oo"  
/* ?=msH=N<l  
**FileAccess.java DCO\c9  
*//文件访问(定位,写) 4"(Bu/24  
package NetFox; [85spub&}  
import java.io.*; \.{$11P#  
x8B}ZIbT9  
cl3K<'D  
public class FileAccessI implements Serializable{ a5^] 20Fa  
< NY^M!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _.Nbt(mz  
RandomAccessFile oSavedFile; s\(k<Ks  
long nPos; 1-uxC^u?|#  
?=7 cF  
|Zpfq63W  
public FileAccessI() throws IOException ^)S;xb9  
{ UgSB>V<?  
this("",0); {<p?2E  
} ZQsJL\x[UK  
{]!mrAjD  
8 >EWKI9  
public FileAccessI(String sName,long nPos) throws IOException M)+H{5bt  
{ 8 ^2oWC#U(  
oSavedFile = new RandomAccessFile(sName,"rw"); gfd"v  
this.nPos = nPos; rU:`*b<  
oSavedFile.seek(nPos); D/xbF`  
} dq6m>;`  
%N6A+5H  
%lhEM}Sm  
public synchronized int write(byte[] b,int nStart,int nLen) CyFrb`%  
{ jD]~ AwRJ  
int n = -1; ZY={8T@  
try{ #U4F0BdA  
oSavedFile.write(b,nStart,nLen); iN\4gQ!  
n = nLen; Yui3+}Ms  
} 85$m[+md  
catch(IOException e) L.2^`mZs  
{ S(l O(gY  
e.printStackTrace (); tjGn|+|k  
} %6,SKg p  
(O?.)jEW(.  
faX#**r  
return n; yCR?UH;  
} \)N9aV  
3?9IJ5p  
J.b9F:&}  
} )h4 f\0  
M61xPq8y5  
wLH>:yKUU  
/* &*,#5.  
**SiteInfoBean.java  .-c4wm}  
*/ Y@vTaE^w3  
package NetFox; W=><)miQ@  
!8d{q)JZ  
- t'jNR'  
public class SiteInfoBean { L:j<c5  
^z IW+:  
h$>-.-  
private String sSiteURL; //Site's URL uAJx.>$b  
private String sFilePath; //Saved File's Path T|eu  
private String sFileName; //Saved File's Name 3g,`.I_  
private int nSplitter; //Count of Splited Downloading File +>{2*\cZ5}  
m@2QnA[ 4  
V)HG(k  
public SiteInfoBean() =JEv,ZGT3  
{//nSplitter的缺省值为5 /<=u\e'rE  
//default value of nSplitter is 5 %KhI>O<  
this("","","",5); Ys!82M$g  
} ^e_hLX\SW  
x7&B$.>3  
wr/"yQA]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qZtzO2Mt  
{ !mJ"gg  
sSiteURL= sURL; v!6  c0a  
sFilePath = sPath; P6-s0]-g  
sFileName = sName; DS(}<HK{  
this.nSplitter = nSpiltter; qFCOUl  
N1}sHyVq7  
u<tbbKM  
} yy^q2P  
'4+ ur`  
{9&;Q|D z  
public String getSSiteURL() !Y0Vid  
{ @]%IK(|  
return sSiteURL; /tx]5`#@7]  
} TOB-aAO  
I(L,8n5  
J s@hLP `  
public void setSSiteURL(String value) \O3m9,a   
{ A5I)^B<(  
sSiteURL = value; rxvx  
} MDZ640-Y  
KK/tu+"  
2>xF){`  
public String getSFilePath() kzQ+j8.,U  
{ X; \+<LE  
return sFilePath; &ZlVWK~v  
} =vCY?I$P  
45@ I*`  
SuJ aL-;  
public void setSFilePath(String value) u^ +7hkk  
{ C\Wmq [  
sFilePath = value; }_M~2L?i  
} ~?Qe?hB  
9iIhte.  
YW,tCtI0_  
public String getSFileName() Cx@);4arj  
{ n`?aC|P2s  
return sFileName; 1y@i}<9F  
} 8sWJcmVo  
17%,7P9pg  
]3],r?-tJ  
public void setSFileName(String value) p?%y82E  
{  lHY+}v0  
sFileName = value; v!-/&}W)1  
} M>xK+q?O  
K*vt;L  
D(@S+r_ota  
public int getNSplitter() O'p9u@kc  
{ T"}5}6rSG  
return nSplitter; y{B=-\O]  
} O-0x8O^B  
93 )sk/j  
T?CdZc.  
public void setNSplitter(int nCount) 4<w.8rR:A  
{ }#RakV4  
nSplitter = nCount; `t>l:<@%  
} X6w6%fzOH>  
} \$~|ZwV{  
Fc)@,/R"v  
R6<X%*&%  
/* Z!a =dnwHz  
**Utility.java $lfn(b,  
*/ hn7# L  
package NetFox; !3c\NbU  
 L^/5ux  
u OmtyX  
public class Utility { [: n'k  
>;aWz%-  
oz\!V*CtK  
public Utility() c)6m$5]  
{ ]`!>6/[  
pGP7nw_g  
8rAg \H3E  
} :DK {Vg6  
[r\Du|R-*  
//线程睡眠 ^&9zw\x;z  
public static void sleep(int nSecond) + B,}Qr  
{ L81ZbNU?$  
try{ <6%?OJhp  
Thread.sleep(nSecond); b i',j0B  
} wQ:)KjhHH  
catch(Exception e) y;m|  
{ 5zK4Fraf  
e.printStackTrace (); ANAVn@ [  
} Ljm[?*H#  
} nSDMOyj+  
o)M}!MT  
//日志 $8)+XmsCr  
public static void log(String sMsg) <`8n^m*  
{ H5/6TX72N  
System.err.println(sMsg); kUb>^- -K  
} B-RjMxX4>  
2lZ Q)   
j7Yu>cr  
public static void log(int sMsg) hE:9{;Gf  
{ &~cBNw|  
System.err.println(sMsg); ^ox=HNV  
} rET\n(AJ  
} >.Pnkx*  
~gJwW+  
etQCzYIhn  
/* do hA0  
**TestMethod.java EgEa1l!NSQ  
*/ ?d\N(s9F  
package NetFox; B B{$&Oh  
d"1]4.c  
mX"oW_EK  
public class TestMethod { +uF>2b6'  
n1ZbRV  
df8k7D;~e  
public TestMethod() ^ 'MT0j  
{ ///xx/weblogic60b2_win.exe etDk35!h~,  
try{ 1/B>XkCJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @,j*wnR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /obfw^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); G6Axs1a  
fileFetch.start(); 4d4ZT?V[  
} *}qWj_RT  
catch(Exception e){e.printStackTrace ();} sPpH*,(  
-a}Dp~j  
5+0gR &|j  
} Lz}OwKl  
0@0w+&*"@  
4&lv6`G `  
public static void main(String[] args) D(op)]8  
{ GRIti9GD  
new TestMethod(); [T4J{y64Y  
} )2KF}{  
} S&5&];Ag  
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