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http断点续传简单实现(java)

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/* hnvn&{|  
**SiteFileFetch.java G( nT.\  
*/ Pgr>qcbql  
package NetFox; wQ2'%T|t  
import java.io.*; y 8];MTl  
import java.net.*; 'hVOK(o 0  
:?RooJ~#  
h K@1 s  
public class SiteFileFetch extends Thread { ORv[Gkq_N)  
lR{eO~'~V  
#| A @  
SiteInfoBean siteInfoBean = null; //文件信息Bean Y%^&aacZ  
long[] nStartPos; //开始位置 }Da8S|)H  
long[] nEndPos; //结束位置 !!o 69  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 CYEqH2"3  
long nFileLength; //文件长度 YXg:cXE8e  
boolean bFirst = true; //是否第一次取文件 _:c8YJEG{  
boolean bStop = false; //停止标志 $$A{|4,aI  
File tmpFile; //文件下载的临时信息 y`mEsj  
DataOutputStream output; //输出到文件的输出流 *.Y! ZaK  
|B)e! #  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) L G,XhN  
public SiteFileFetch(SiteInfoBean bean) throws IOException =Q.2:*d.  
{ gEO#-tMjOQ  
siteInfoBean = bean; l#~Sh3@L(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); {u9(qd;;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); fF_1ZKx+#!  
if(tmpFile.exists ()) kkyn>Wxv  
{ NX@TWBn%  
bFirst = false; .m;1V6  
read_nPos(); dB<BEe\$g.  
} ZA1?'  
else , y{o!w  
{ _S,2j_R9  
nStartPos = new long[bean.getNSplitter()]; \&2GLBKpe  
nEndPos = new long[bean.getNSplitter()]; ;#EB0TK  
} cw/g1,p  
(FH4\'t)  
3y r{B Xn  
6DaH+  
} m1]rLeeEt  
?5$\8gZ  
@D9c  
public void run()  42Gr0+Mb  
{ 89`AF1  
//获得文件长度 O *H:CW  
//分割文件 MZ=U} &F  
//实例FileSplitterFetch }UXj|SY  
//启动FileSplitterFetch线程 0Ny0#;P  
//等待子线程返回 yeE_1C .  
try{ H<}<f:  
if(bFirst)  Tx/  
{  Ca@[]-_H  
nFileLength = getFileSize(); -R~;E[ {%  
if(nFileLength == -1)  O7s0M?4  
{ #T#&qo#  
System.err.println("File Length is not known!"); z.e%AcX  
} 1 YMaUyL 1  
else if(nFileLength == -2) &^ =t%A%#  
{ g}ciG!0  
System.err.println("File is not access!"); xfkG&&  
} '[qG ,^f  
else 'bY^=9&|  
{ ;l4rg!r(S  
for(int i=0;i<nStartPos.length;i++) u5V<f;  
{ *vJ1~SRV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?F AsV&y  
} b1nw,(hLY  
for(int i=0;i<nEndPos.length-1;i++) `USR]T_`  
{ 9.zy`}  
nEndPos = nStartPos[i+1]; q{yz]H,  
} &r~~1BnpHm  
nEndPos[nEndPos.length-1] = nFileLength; $d,30hK  
} B(Y{  
} YwoytoXK  
%[lX  H  
r5lp<md  
//启动子线程 DXSZ#^,S[W  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D G7FG--  
for(int i=0;i<nStartPos.length;i++) (z ;=3S  
{ <g>_#fz"K  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y8m|f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C([;JO 11[  
nStartPos,nEndPos,i); *3S,XMS{O  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (G#)[0<fX  
fileSplitterFetch.start(); pSE"] N  
} <~"qz*_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T-fW[][&$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4{CVBowi  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9m!4U2N,s  
nEndPos = " + nFileLength); `9a%}PVQ-  
// fileSplitterFetch[nPos.length-1].start(); [p}J=1S  
=<`9T_S 16  
T*k K-@.i  
//等待子线程结束 Q!GB^ P  
//int count = 0; hrU.QF8  
//是否结束while循环 Yi7`iC  
boolean breakWhile = false; b'M g  
d";+8S  
cFGP3Q4{  
while(!bStop) !uO|1b  
{ vq(@B  
write_nPos(); "4`h -Y  
Utility.sleep(500); c#u-E6  
breakWhile = true; KSh<_`j  
ll[U-v{  
KDRIy@[e  
for(int i=0;i<nStartPos.length;i++) a3R#Bg(  
{ u;!CQ w/  
if(!fileSplitterFetch.bDownOver) 7k+UCi u>  
{ 9y.C])(2  
breakWhile = false; C<qJnB:B 9  
break; h(GgkTj4+  
} +s1+;VUs3  
} /Lu wPM  
if(breakWhile) jTSw0\}  
break; *ubLuC+b  
lG%oqxJ+ L  
o \b8lwA,  
//count++; CN\s,. ]  
//if(count>4) 1ReO.Dd`R  
// siteStop(); 9WtTUk  
} OR1XQij  
mOGcv_L  
:!g|0CF_  
System.err.println("文件下载结束!"); ^4B6IF*  
} yK"U:X  
catch(Exception e){e.printStackTrace ();} i @+Cr7K,  
} FT`y3 ~  
Ug3PZ7lK  
-Zocu<Rs  
//获得文件长度 ;#` Z(A}  
public long getFileSize() f 7d)  
{ y'2K7\>E  
int nFileLength = -1; >,uof?  
try{ Xw9,O8}C7  
URL url = new URL(siteInfoBean.getSSiteURL()); e)!X9><J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A ;Z%-x  
httpConnection.setRequestProperty("User-Agent","NetFox"); q Z`@Ro  
V)!Oss;i  
_V-@95fK  
int responseCode=httpConnection.getResponseCode(); RL.%o?<&?  
if(responseCode>=400) +Nc|cj  
{ ?P{C=Td2z  
processErrorCode(responseCode); N5%~~JRO  
return -2; //-2 represent access is error EJdq"6S  
} 3"I 1'+  
Tk.MtIs)V}  
Q}\,7l  
String sHeader; 2ZIf@C{P.  
G dL\  
m]7Y )&3  
for(int i=1;;i++) cCyg&% zsT  
{ w V2 7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6tzZ j:y q  
//Utility.log(in.readLine()); Ujq)h:`  
sHeader=httpConnection.getHeaderFieldKey(i); FE/&<g0,:  
if(sHeader!=null) MSRIG-  
{ -Ah\a0z  
if(sHeader.equals("Content-Length")) 3w!oJB  
{ wpx,~`&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )z7. S"U  
break; GlQ=M ) E  
} (t<i? >p  
} g>OGh o  
else V %Y.N4H  
break; Lm,io\z  
} f=} u;^  
} ;u}MG3Y8  
catch(IOException e){e.printStackTrace ();} cpu+"/\  
catch(Exception e){e.printStackTrace ();} >4LX!^V"  
!Q#u i[0q  
P,I3E?! j  
Utility.log(nFileLength); u`E_Q8  
Q`r1pO  
+n2x@ 0op  
return nFileLength; ;E* ^AW  
} zx#d _SVi  
<XCH{Te1  
47$JN}qI0  
//保存下载信息(文件指针位置) >s[}f6*2@  
private void write_nPos() Z#7HuAF{]  
{ +1h^9 Y'  
try{ >a_K:O|AJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1;ZEuO  
output.writeInt(nStartPos.length); ?em)om  
for(int i=0;i<nStartPos.length;i++) nez5z:7F  
{ g.F{yX]  
// output.writeLong(nPos); F^A1'J  
output.writeLong(fileSplitterFetch.nStartPos); +/x|P-  
output.writeLong(fileSplitterFetch.nEndPos); ; h/Y9uYn  
} _IT,>#ba  
output.close(); 2R<1  ^  
} 6D0uLh  
catch(IOException e){e.printStackTrace ();} ',juZ[]_ {  
catch(Exception e){e.printStackTrace ();} g&_0)(a\  
} Sq(=Bn6E  
~5p `Kg*  
[}P|OCW  
//读取保存的下载信息(文件指针位置) "UVV/&`o  
private void read_nPos() t@4X(i0  
{ 1DZGb)OU  
try{ u"C`S<c  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); TN/I(pkt1B  
int nCount = input.readInt(); L d#  
nStartPos = new long[nCount]; 9&rn3hmP  
nEndPos = new long[nCount]; b-~`A;pr  
for(int i=0;i<nStartPos.length;i++) Szwa2IdI.  
{ mUnn k`v  
nStartPos = input.readLong(); yKDg ~zsh  
nEndPos = input.readLong(); 2Q1* Xq{  
} Zh3]bg5  
input.close(); 3bE^[V8/  
} }c&Zv#iO6  
catch(IOException e){e.printStackTrace ();} $5il]D`  
catch(Exception e){e.printStackTrace ();} }"q1B  
} eYsO%y\I  
W{ Nhh3  
'-W p|A  
private void processErrorCode(int nErrorCode) Y;-"Z  
{ zg8m(=k'  
System.err.println("Error Code : " + nErrorCode); IXd&$h]Lq  
} ~jF5%Gu  
|$bZO`^  
|6_<4lmTxF  
//停止文件下载 pjbKMx  
public void siteStop() K")-P9I6-f  
{ Jc{zi^)(EN  
bStop = true; 8)R )h/E>  
for(int i=0;i<nStartPos.length;i++) b3Y9  
fileSplitterFetch.splitterStop(); z%mM#X  
xA&G91|s  
:hxfd b-  
} f$(w>B7..  
} .>CqZN,^  
//负责部分文件的抓取 {&K#~[)  
**FileSplitterFetch.java p(f)u]1`  
*/ 3y 0`G8P'h  
package NetFox; mnu7Y([2>  
E37`g}ZS  
9D8el}uHf  
import java.io.*; nSd?P'PFg  
import java.net.*; X)~JX}-L  
I:mJWe  
F_V~UX1D  
public class FileSplitterFetch extends Thread { /xf %Rp4}  
3ck;~Ncj<  
?bN8h)>QQ8  
String sURL; //File URL 173/A=]  
long nStartPos; //File Snippet Start Position m[Zz(tL  
long nEndPos; //File Snippet End Position +yCIA\i#t6  
int nThreadID; //Thread's ID M=0I 3o}J  
boolean bDownOver = false; //Downing is over TioI$?l>W(  
boolean bStop = false; //Stop identical N'2u`br4KP  
FileAccessI fileAccessI = null; //File Access interface fa<83<.D  
[!bTko>rSB  
<niHJ*  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException '%K,A-7W  
{ L & PhABZ  
this.sURL = sURL; LuQ=i`eXx  
this.nStartPos = nStart; /!7m@P|&D  
this.nEndPos = nEnd; B;7L:  
nThreadID = id; #C !8a  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #kma)_X  
} m"+9[d_u  
xx9qi^  
tLV9b %i(  
public void run() yt_?4Hc"  
{ o{zo-:>Jp  
while(nStartPos < nEndPos && !bStop) {I(Euk>lR  
{ K6|*-Wo.  
'lIT7MK  
7CwG(c/5  
try{ M[TgNWl/[  
URL url = new URL(sURL); 7b'XQ/rs  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `n5|4yaG~  
httpConnection.setRequestProperty("User-Agent","NetFox"); "p$`CUtI  
String sProperty = "bytes="+nStartPos+"-"; ] J:^$]  
httpConnection.setRequestProperty("RANGE",sProperty); hnG'L*HooE  
Utility.log(sProperty); Z;??j+`Eo  
:LcR<>LZ  
i~l0XjQbs  
InputStream input = httpConnection.getInputStream(); $?;aW^E  
//logResponseHead(httpConnection); ze,HN Fg@>  
,|T   
s(wbsRVP8  
byte[] b = new byte[1024]; t ;y>q  
int nRead; . 6Bz48*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) S ._9  
{ c9f~^}jNb  
nStartPos += fileAccessI.write(b,0,nRead); $&lS7}  
//if(nThreadID == 1) h'kgL~+$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #^Sd r-   
} :ykQ[d`:|  
+s_@964  
r 97 VX>  
Utility.log("Thread " + nThreadID + " is over!"); O]lWaiR`  
bDownOver = true; Q[8L='E  
//nPos = fileAccessI.write (b,0,nRead); n*bbmG1  
} KvktC|~?  
catch(Exception e){e.printStackTrace ();} M}M.  
} qw"`NubX  
} :5h&f  
l'-iIbKX  
ogjm6;  
//打印回应的头信息 (x?A#o>%  
public void logResponseHead(HttpURLConnection con) \JN<"/  
{ ,bJZs-P0  
for(int i=1;;i++) e&]XiV'  
{ "t4~xs`~X  
String header=con.getHeaderFieldKey(i); QLIm+)T  
if(header!=null) s u![ST(  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  dsJ}C|N  
Utility.log(header+" : "+con.getHeaderField(header)); $WTu7lVV[1  
else #2x\d  
break; b6);bX>e  
} 8(uxz84ce  
} n;O 3.2  
DB%=/ \U  
3(vI{[yhT  
public void splitterStop() 4*m\Zoq>  
{ E})PNf;  
bStop = true; C{Aeud #5  
} y>Nlj%XH  
. KRh59yg  
D~2,0K  
} ?]$.3azO  
Ct #hl8b:  
#T !YFMh;  
/* |{ *ce<ip5  
**FileAccess.java }$g5:k!  
*//文件访问(定位,写) ?^,GaZ^V  
package NetFox; T[ky7\  
import java.io.*; /mqEc9sq,  
SU H^]4>  
8!:4m"Y  
public class FileAccessI implements Serializable{ nLo:\I(  
mN ~;MR;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C5;"mo-  
RandomAccessFile oSavedFile; 7xWX:2l*?  
long nPos; #4~Ivj  
bumS>:  
!m]76=@  
public FileAccessI() throws IOException >I!dJH/gj  
{ e2/[`k=7-  
this("",0); pMs%`j#T  
} :/ "q NPJ  
,uDB ]  
l^"gpO${K  
public FileAccessI(String sName,long nPos) throws IOException Kd^ ._  
{ 9J l9\y9  
oSavedFile = new RandomAccessFile(sName,"rw"); PJkEBdM.  
this.nPos = nPos; o7hjx hmC  
oSavedFile.seek(nPos); ))306*X\  
} o.y4&bC14;  
^H&6'A`  
]9b*!n<z  
public synchronized int write(byte[] b,int nStart,int nLen) H( cY=d,  
{ #?8'Z/1 )  
int n = -1; [.3M>,)+-  
try{ 7!L"ef62o  
oSavedFile.write(b,nStart,nLen); NV*t  
n = nLen; ,4EE9 ?J  
} 5TzMv3;in2  
catch(IOException e) kO/dZ%vj  
{ ob-be2EysH  
e.printStackTrace (); `?`\!uP"  
} ?vM{9!M  
Hyc19|  
W)j/[  
return n; ;QW)tv.y  
} 3%k@,Vvt  
FnL~8otPF'  
|A0kbC.  
} 3osAWSCEL  
okr'=iDg  
5b|_?Em7  
/* //| 9J(B]  
**SiteInfoBean.java >&Bg F*mm  
*/ P+oCcYp  
package NetFox; ]Nsb V  
X8?|5$Ey  
4sROMk=l  
public class SiteInfoBean { [+ 1([#  
)mp0k%  
W\FKA vS  
private String sSiteURL; //Site's URL WS2TOAya)  
private String sFilePath; //Saved File's Path YwHnDVV+  
private String sFileName; //Saved File's Name q$U;\Mg)  
private int nSplitter; //Count of Splited Downloading File oX!s u  
-OVJ]  
}7Pd\tG]  
public SiteInfoBean() >Li ~Og@  
{//nSplitter的缺省值为5 rZGA9duy  
//default value of nSplitter is 5 =cqaA^HQL  
this("","","",5); ZLo3 0*  
} sveFxI  
tA'i-D&  
Q/0;r{@Tq}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ezHj?@  
{ N b(se*Y#  
sSiteURL= sURL; )lH?XpfTjm  
sFilePath = sPath; `(Ei-$ >U&  
sFileName = sName; 6n;ewl}  
this.nSplitter = nSpiltter;  @(Q4  
&X +@,!  
sOVaQ&+y  
} jZ.+b j >  
+ ZGOv,l  
NE3G!qxL  
public String getSSiteURL() +.[#C5  
{ gy~M]u{  
return sSiteURL; q;Qpd]H  
} ]Jv Z:'g}  
.L6t3/^  
7.akp  
public void setSSiteURL(String value) )M^;6S  
{ GTJ\APrH  
sSiteURL = value; C, jPr )6)  
} R)G'ILneV  
9Q].cDe[  
YQe @C  
public String getSFilePath() LOe!qt\&  
{ ,CwhpW\Y  
return sFilePath; ;2%3~L8?V  
} [y>Q3UqN  
/rJvw   
9.PY49|  
public void setSFilePath(String value) ;41s&~eR  
{ mQ' ]0DS  
sFilePath = value; rPr#V1}1a  
} rA{h/T"  
_czLKbcF  
KasOh"W.P  
public String getSFileName() +Y 3_)  
{ h'T\gF E%  
return sFileName; UDuKG\_J<y  
} WDgp(Av!  
,gD30Pylz  
mX,#|qLf  
public void setSFileName(String value) } vcr71u  
{ ZOS{F_2.  
sFileName = value; 1&wZJP=  
} t41\nTZr  
ki}Uw#  
G|Q}.v  
public int getNSplitter() 8>O'_6Joj  
{ TvM{ QGN  
return nSplitter; VwtGHF'  
} c.jnPVf:  
_FAwW<S4B  
T /[)U  
public void setNSplitter(int nCount) B(b[Dbb  
{ {jlm]<:&Z  
nSplitter = nCount; ?;uzx7@F  
} .[K{;^>  
} 9HP)@66  
EKwS~G.b!  
X(E f=:  
/* )Q7;)iPY#  
**Utility.java {"4t`dM  
*/ gxt2Mq;q~}  
package NetFox; SHz& o[u  
eb.`Q+Gb  
MV=.(Zs  
public class Utility { 5dYIL`  
7 yF#G9,  
EEaKT`/d  
public Utility() /R@(yT=t  
{ <|.S~HLTQ  
@LwhQ  
2evM|Dj  
} ^{Syg;F=  
XXe7w3x{  
//线程睡眠 ( B50~it  
public static void sleep(int nSecond) !?Ow"i-lp  
{ _k6N(c2Nd  
try{ 4 Ag+  
Thread.sleep(nSecond); U.>n]/&  
} ,9W0fm \t  
catch(Exception e) QHtpCNTVb  
{ -pX/Tt6  
e.printStackTrace (); 5zEl`h  
} eaF5S'k 4$  
} V @d:n  
P[gk9{sv  
//日志 QC ]z--wu  
public static void log(String sMsg) w8> T ~Mv  
{ 7d'@Z2%J0  
System.err.println(sMsg); hM>xe8yE  
} vuw1ycy)  
)xTp7YnZ;  
bh+R9~  
public static void log(int sMsg) }8x[  
{ A$1pMG~as  
System.err.println(sMsg); Y]P $|JW):  
} y>wr $  
} D8Ni=.ALL  
I`5MAvP  
+{Q\B}3cj1  
/* i<%(Z[9Lk  
**TestMethod.java .dM 0  
*/ /a9+R)Al  
package NetFox; \a|gzC1G  
2.; OHQTE  
.l#Pmd!  
public class TestMethod { _KD(V2W  
ijoR(R^r  
+8 6\&y)  
public TestMethod() .:<c[EJ b  
{ ///xx/weblogic60b2_win.exe dcXtT3,kpX  
try{ i37W^9 R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !pDS*{)E  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *sL'6"#Cre  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +.>O%pNj  
fileFetch.start(); z!RA=]3h  
} Z39^nGO  
catch(Exception e){e.printStackTrace ();} >1joCG~  
3zh'5qQ  
Q[~O`Lz  
} p&ow\A O  
P#Eqe O  
'n>|jw)  
public static void main(String[] args) %f:'A%'Qb  
{ g:f0K2)\r:  
new TestMethod(); q:?g?v  
} 0imz }Z]  
} uy`U1>  
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