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http断点续传简单实现(java)

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/* x;s0j"`Jb  
**SiteFileFetch.java M@et6aud;K  
*/ L%"LlS g  
package NetFox; C[sh,  
import java.io.*; 6gL-OJNo  
import java.net.*; iUi>y.}"P  
|{>ER,<-  
&@FhR#pUQ  
public class SiteFileFetch extends Thread { }<a^</s  
SmwQET<H  
h^UKT`9vt  
SiteInfoBean siteInfoBean = null; //文件信息Bean #W>QY Tp  
long[] nStartPos; //开始位置 cVnJ^*Z  
long[] nEndPos; //结束位置 /]^#b  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8^/I>0EZ  
long nFileLength; //文件长度 sgUud_r)4  
boolean bFirst = true; //是否第一次取文件 *ISZlR\#  
boolean bStop = false; //停止标志 !]yO^Ob.E  
File tmpFile; //文件下载的临时信息 KngTc(^_D  
DataOutputStream output; //输出到文件的输出流 zAzP,1$?  
mHc>"^R  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) )kXhtjOl|  
public SiteFileFetch(SiteInfoBean bean) throws IOException dt@P>rel  
{ 2Os1C}m  
siteInfoBean = bean; >Gml4vGK  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %QmxA 7fW  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Zdc63fllM  
if(tmpFile.exists ()) W,5Hx1z R  
{ W !w,f;  
bFirst = false; XRx+Dddt;  
read_nPos(); EOj"V'!  
} b?X.U}62_  
else l e4?jQQ@L  
{ Fb`a~c~s  
nStartPos = new long[bean.getNSplitter()]; <7SpEVQ  
nEndPos = new long[bean.getNSplitter()]; t_^X$pL  
} sUJ%x#u}Fk  
)SF}2?7e  
b//B8^Eong  
x+8_4>,>Y7  
} afBE{  
2Y\ d<.M  
{9Y+.46S  
public void run() D"(L5jR8m@  
{ g[RI.&?  
//获得文件长度 4fk8*{Y  
//分割文件 ULrr=5&8  
//实例FileSplitterFetch !* Ti}oIo&  
//启动FileSplitterFetch线程 jp8@vdRg  
//等待子线程返回 -i0(2*<  
try{ `nM/l @  
if(bFirst) o8/ ;;*  
{ 4;n6I)&.(  
nFileLength = getFileSize(); #} ~qqJ G2  
if(nFileLength == -1) -}O1dEn.  
{ L37Y+C//  
System.err.println("File Length is not known!"); {vUN+We  
} ('wY9kvL&  
else if(nFileLength == -2) &qp r*17T  
{ 1tTg P+  
System.err.println("File is not access!"); g VQjL+_W  
} Nkxm m/Z  
else `ps)0!L L`  
{ u H/w\v_I  
for(int i=0;i<nStartPos.length;i++) kpL@P oQ/r  
{ FuI73  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \%PaceH  
} 1XM^8 .;  
for(int i=0;i<nEndPos.length-1;i++) ku$$ 1xq  
{ S}APQ  
nEndPos = nStartPos[i+1]; JD@J[YY5R  
} Tc8 un.  
nEndPos[nEndPos.length-1] = nFileLength;  N\:. M  
} eP*lI<NQ1  
} { eCC$&"  
m'P1BLk  
J)P$2#  
//启动子线程 /VmR<C?h  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; R\o<7g-|  
for(int i=0;i<nStartPos.length;i++) yFDv6yJ.  
{ 2gO2jJlv  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IDnC<MO>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >:D j\"o  
nStartPos,nEndPos,i); 'cY` w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o-}R?>  
fileSplitterFetch.start(); :ba5iMa  
} 2M# r]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 311LC cRp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :Ad &$e g+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", t#q<n:WeYU  
nEndPos = " + nFileLength); pZ/>[TP(%F  
// fileSplitterFetch[nPos.length-1].start(); !rqF}d  
/~x "wo  
EEGy!bff  
//等待子线程结束 f B9;_z  
//int count = 0; KII *az  
//是否结束while循环 R|wGU)KEc'  
boolean breakWhile = false; _.L4e^N&UO  
<n]x#0p  
3p0LN'q]A  
while(!bStop) %Gt .m  
{ PRz/inru-  
write_nPos(); _YcA+3ZL  
Utility.sleep(500); v\p;SwI   
breakWhile = true; \&H nKhI  
M5xCC!  
2W4qBaG$=  
for(int i=0;i<nStartPos.length;i++) @)Ofi j  
{ jBegh9KHq  
if(!fileSplitterFetch.bDownOver) fk_o@ G!0  
{ sQMFpIrr  
breakWhile = false; DGzw8|/(  
break; ,3@#F/c3i~  
} In`mtn q  
} FJasS8  
if(breakWhile) *Z|y'<s  
break; y@\V +  
Yo[;W vu  
qWmQ-|Py  
//count++; "~D]E7Q3y  
//if(count>4) I1PuHf Qs  
// siteStop(); xQUu|gtL4  
} !Q#{o^{Y~  
m=YU2!Mb  
K_dOq68_  
System.err.println("文件下载结束!"); DZi!aJ  
} o865 (<p  
catch(Exception e){e.printStackTrace ();} 5}`_x+$%(`  
} _-EyT  
3YVi" k?2  
-|E!e.^7:  
//获得文件长度 ;VWAf;U;B  
public long getFileSize() $sEy%-  
{ Uw 47LP  
int nFileLength = -1; St e=&^  
try{ ih7/}   
URL url = new URL(siteInfoBean.getSSiteURL()); 9(@\&>)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XGl+S  
httpConnection.setRequestProperty("User-Agent","NetFox"); mvq&Pj 1}L  
`QXErw  
:s4p/*f  
int responseCode=httpConnection.getResponseCode(); b,C aWg  
if(responseCode>=400) 7D<#(CE{  
{ ]MxC_V+P`  
processErrorCode(responseCode); {7)st W  
return -2; //-2 represent access is error Z,=7Tu bR#  
} Y'ow  
B[KJR?>  
aoXb22]{  
String sHeader; mya_4I m  
;Rv!k&Df  
/kfgx{jZ  
for(int i=1;;i++) ['T:ea6B  
{ C+TI]{t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); P'`r  
//Utility.log(in.readLine()); )a-Du$kd  
sHeader=httpConnection.getHeaderFieldKey(i); "sG=wjcw^  
if(sHeader!=null) ariLG [:X  
{ nJo`B4'U  
if(sHeader.equals("Content-Length")) .C--gQpIv  
{ (;q;E\Ej q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); zzyHoZJP  
break; ({q?d[q[  
} 6q{HU]N+  
} Bro9YP4<  
else B&@?*^.  
break; R00eisd  
} )BwjZMJ.N  
} ?O8ViB?2  
catch(IOException e){e.printStackTrace ();} Z-l=\ekJ  
catch(Exception e){e.printStackTrace ();} PS[+~>%  
mFi&YpH u3  
%T~ig[GstX  
Utility.log(nFileLength); 6Aku1h  
tQjLOv+?=  
@~%r5pz6  
return nFileLength; =F@W gn,  
} (JM5`XwM  
GSRVe/ [  
!7kG!)40  
//保存下载信息(文件指针位置) O)jWZOVp >  
private void write_nPos() ,]d,-)KX8  
{ gntxNp[9T  
try{ 3d e_V|%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /bi}'H+#  
output.writeInt(nStartPos.length); sIxTG y.  
for(int i=0;i<nStartPos.length;i++) ;LMJd@  
{ pim!.=vN/U  
// output.writeLong(nPos); #H :7@  
output.writeLong(fileSplitterFetch.nStartPos); hy`?E6=9+  
output.writeLong(fileSplitterFetch.nEndPos); gy_>`16K  
} /\hzb/  
output.close(); HbxL:~:}J  
} m8o(J\]  
catch(IOException e){e.printStackTrace ();} ]]*7\ :cb  
catch(Exception e){e.printStackTrace ();} *#C+iAF|)'  
} lk( }-  
v~^{{O  
$GTU$4u  
//读取保存的下载信息(文件指针位置) 1#ft#-g}  
private void read_nPos() @9lUSk^9  
{ eb=D/  
try{ #':fkIYe'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7BJzM lJ1Y  
int nCount = input.readInt(); QC9eUYe  
nStartPos = new long[nCount]; o<|P9#(U"  
nEndPos = new long[nCount]; }3OKC2K~  
for(int i=0;i<nStartPos.length;i++) W;,C_   
{ 6Q${U7%7  
nStartPos = input.readLong(); y$_eCmq  
nEndPos = input.readLong(); "\3B^ e,  
} egq67S  
input.close(); E/%9jDTQ  
} u)~C;f)  
catch(IOException e){e.printStackTrace ();} zc;|fHW~O  
catch(Exception e){e.printStackTrace ();} E<Q f!2s$  
} RH&~+5  
i*@< y/&'  
iT%} $Lu~  
private void processErrorCode(int nErrorCode) G{6;>8h  
{ K5xX)oV  
System.err.println("Error Code : " + nErrorCode); ~1>.A(,=z  
} :R~MO&  
k@z,Iq8  
!lj| cT9  
//停止文件下载 PEW=@xj2y  
public void siteStop() 'LE =6{#  
{ jW  3c"  
bStop = true; LILQ\I<<'  
for(int i=0;i<nStartPos.length;i++) 3GUZ;jdn  
fileSplitterFetch.splitterStop(); 3U7 *>H  
C,v(:ZE$J7  
vy\RcP  
} &M.66O@  
} D F*:_B )  
//负责部分文件的抓取 ,f[>L|?e  
**FileSplitterFetch.java OHhsP}/  
*/ +Zaj,oEE  
package NetFox; T Kg aV;92  
rV T{90,  
,uSQNre\j  
import java.io.*; -@0GcUE:r  
import java.net.*; *U P@9D  
EV*IoE$W]=  
_N{RVeO  
public class FileSplitterFetch extends Thread { @n{JM7ctJ  
u[DfzH  
N-e @j4WU  
String sURL; //File URL IX>d`O61*g  
long nStartPos; //File Snippet Start Position \uaJ @{Vug  
long nEndPos; //File Snippet End Position <gQIq{B?  
int nThreadID; //Thread's ID Ir qZi1  
boolean bDownOver = false; //Downing is over O vk_\On  
boolean bStop = false; //Stop identical GJoS #s  
FileAccessI fileAccessI = null; //File Access interface Z2'Bk2 L  
0 g?z&?  
d~JKH&x<  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException jAm3HI   
{ +PcmJ  
this.sURL = sURL; PqiB\~o@Z  
this.nStartPos = nStart; T^Ze3L]  
this.nEndPos = nEnd; 9Ru8~R/\  
nThreadID = id; nv~%#|v_W  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8[E!E)4M  
} r}mbXvn  
=9fajRFTt  
&i$ldR  
public void run() f]\CD<g3|E  
{ R' !  
while(nStartPos < nEndPos && !bStop) /XzH?n/{R  
{ ,Q HU_jt  
IHcD*zQ  
9 mmCp&~Z  
try{ B#.L  
URL url = new URL(sURL); b"#WxgaF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y}#J4i0b*  
httpConnection.setRequestProperty("User-Agent","NetFox"); QT>`^/]d  
String sProperty = "bytes="+nStartPos+"-"; U8LtG/  
httpConnection.setRequestProperty("RANGE",sProperty); G"Sd@%W(  
Utility.log(sProperty); er!DYv  
:[hgxJu+  
+/)#( j@  
InputStream input = httpConnection.getInputStream(); S|]X'f  
//logResponseHead(httpConnection); b-{=s +:  
?C&z]f3(:  
K0 }p i +=  
byte[] b = new byte[1024]; JU^lyi!  
int nRead; ]Zyur`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) w[I E  
{ RIY,K*f.  
nStartPos += fileAccessI.write(b,0,nRead); T`;%TO*Y  
//if(nThreadID == 1) 8(~K~q[Cr  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %\H|B0  
} `m!j$,c.  
k=4N.*#`y  
CkdP#}f  
Utility.log("Thread " + nThreadID + " is over!"); ^7 &5 z&o  
bDownOver = true; PGLplXb#[S  
//nPos = fileAccessI.write (b,0,nRead); ~s]iy9i  
} RHO(?8"_  
catch(Exception e){e.printStackTrace ();} 2E)wpgUc?e  
} s0k`p<q  
} n1VaLD  
CB/D4j;  
9Bw|(J  
//打印回应的头信息 5 ({t4dm  
public void logResponseHead(HttpURLConnection con) .MJofE;Jn  
{ ^wc"&;=c|  
for(int i=1;;i++) (<}&DE  
{ /q5v"iX]T  
String header=con.getHeaderFieldKey(i); 37|&?||  
if(header!=null) ak |WW]R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); z2QP)150  
Utility.log(header+" : "+con.getHeaderField(header)); g'V>_u#(  
else -1U D0(  
break; D-4f >  
} 7zSLAHW  
} NT+?  #0I  
Z^IPZF  
#>mr[   
public void splitterStop() Qg[/%$x.  
{ ;[ u%_  
bStop = true; obNqsyc77R  
} p|&Yku=  
2L} SJUk*  
g#t[LI9(F[  
} }7 c[Q($K  
 \V*xWS  
 .5y+fL  
/* 1r]Io gI  
**FileAccess.java gm[z[~X@  
*//文件访问(定位,写) {yB&xj[z  
package NetFox; aM:nOt" S1  
import java.io.*; $l|qk  z  
"vyNxZE  
aW`Lec{.  
public class FileAccessI implements Serializable{ c;n *AK  
'-"/ =j&d[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 j"'(sW-  
RandomAccessFile oSavedFile; m|:_]/*qE  
long nPos; !=:$lzS^  
/x[jQM\  
7|[mz> "d  
public FileAccessI() throws IOException @>)r}b  
{ yX0dbW~@y  
this("",0); ,H19`;Q  
} Wu_kx2h  
9)gC6 IiW  
LG1r]2  
public FileAccessI(String sName,long nPos) throws IOException )Hk3A$6(  
{ %^>ju;i^O  
oSavedFile = new RandomAccessFile(sName,"rw"); !Y\D?rKZ  
this.nPos = nPos; <RG|Dx[:=  
oSavedFile.seek(nPos); DFd%9*N  
} NF0%}II&xK  
o)2W`i&  
 )8UWhl=  
public synchronized int write(byte[] b,int nStart,int nLen) AbYqf%~7`l  
{ ZObhF#Y9  
int n = -1; t{WzKy  
try{ O2BDL1o  
oSavedFile.write(b,nStart,nLen); naw0$kXTA  
n = nLen; fI~Xmw+}}  
} Ts ^"xlK  
catch(IOException e) P}TI q#  
{ mHBnC&-/  
e.printStackTrace (); T<w5vqFDu  
} qASqscO  
uec!RKE  
 uJ5Eka  
return n; m:WyuU<  
} , eZ1uBI?  
Qi LEL  
%d(^d  
} .%Ta]!0  
X~<("  
w`il=ZAC  
/* e*;c(3>(  
**SiteInfoBean.java ulkJR-""&  
*/ /U"CO8Da  
package NetFox; eL\;Nf+Zp  
>ey\jDr#O  
43Qtj$F  
public class SiteInfoBean { 7qg{v9|,  
]jaQ[g$F  
P3nb2.  
private String sSiteURL; //Site's URL q&/Yg,p\  
private String sFilePath; //Saved File's Path NNE<L;u  
private String sFileName; //Saved File's Name V %YiAr>  
private int nSplitter; //Count of Splited Downloading File I S#FiH  
zOqn<Y@  
!>e5z|1   
public SiteInfoBean() }c`fW&  
{//nSplitter的缺省值为5 X(\fN[;  
//default value of nSplitter is 5 weE/TW\e  
this("","","",5); UF<uU-C"  
} fe_yqIdk  
$n+w$CI)  
;ml)l~~YU  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) LK, bO|  
{ Pp`*]Ib  
sSiteURL= sURL; bVL9vNK  
sFilePath = sPath; 3plzHz,x  
sFileName = sName; 'C ~ y5j  
this.nSplitter = nSpiltter; 8-_QFgY  
_&j}<K$- (  
_`_%Y(Xat  
} w - Pk7I  
'eJ+JM<0%  
b D[!/'4eJ  
public String getSSiteURL() M5*{  
{ I{lT>go  
return sSiteURL; ,>:;#2+og  
} #L{OV)a<  
3'c0#h@VD  
N\#MwLm  
public void setSSiteURL(String value)  k7>|q"0C  
{ kRTwaNDOD  
sSiteURL = value; -x'z XvWZ  
} 839IRM@'5  
qZh1`\G  
;IVDr:  
public String getSFilePath() 8ZKo_I\  
{ ~d%Pnw|  
return sFilePath; FFH_d <q  
} NDs!a  
niqN{  
`xywho%/Y  
public void setSFilePath(String value) gOr%!QaF  
{ `S2[5i  
sFilePath = value; 8g:;)u4$P  
} BVr0Gk  
Gu'rUo3Do  
Pj4/xX  
public String getSFileName() h~p>re  
{ o4%y>d)  
return sFileName; )EL!D%<A  
} >layJt  
+> WM[o^I  
AwTJJ0>  
public void setSFileName(String value) "v`   
{ Z7_ zMM  
sFileName = value; )E,\H@A  
} y-j\zK  
rc/nFl 6#  
8:#rA*Y  
public int getNSplitter() Pp| *J^U 4  
{ ;Wl+ zw  
return nSplitter; *_KFW@bC:  
} CWNx4)ZGw  
8S<@"v  
B?)@u|0  
public void setNSplitter(int nCount) raCi 8  
{ m^#rB`0;L  
nSplitter = nCount; d ,Y#H0`  
} &CIVL#];e  
} un=2}@ '  
+q)5dYRzV  
n#:N;T;\a  
/* K\$J4~EtG  
**Utility.java a9T@$:  
*/ Ma\Gb+>  
package NetFox; e+j)~RBnu3  
\N4 y<  
U R%4@   
public class Utility { '2laTl]`  
GN0`rEh  
A5H3%o(6k  
public Utility() #fL8Kq  
{ \igmv]G%  
G <uyin>  
GQl$yZaK{  
} +8#_59;x  
y8 KX<2s1  
//线程睡眠 XO9M_*Va  
public static void sleep(int nSecond) S_T1y  
{ ]a! xUg!S  
try{ 1|?05<8  
Thread.sleep(nSecond); ! /NG.Wf  
} J%jB?2 1:o  
catch(Exception e) c= x,ijY "  
{ :T._ba3|  
e.printStackTrace (); v\,N5  
} ,i0b)=!o  
} gi-Yqco  
=r.mlc``W  
//日志 }->.k/vc  
public static void log(String sMsg) #_|sgS?1  
{ K3' niGT  
System.err.println(sMsg); rC7``#5  
} 2<][%> '  
F! X}(N?t  
+E;2d-x*p  
public static void log(int sMsg) sU"}-de  
{ h@@nR(<i  
System.err.println(sMsg); eXkujjSw"  
} (__yh^h:m  
} 7;tJK^J`  
#CnHf  
nD0}wiL{  
/* I0'[!kBF|  
**TestMethod.java T /mI[*1xI  
*/ iajX~kv  
package NetFox; L3p`  
78Aa|AJU  
UDc$"a}ds{  
public class TestMethod { /\w)>0  
R'dSbn  
'r@:Cz3e*I  
public TestMethod() qU,c~C=Qf  
{ ///xx/weblogic60b2_win.exe eVR5Xar  
try{ v$)q($}p  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Yyfq  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); g!`3{ /4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); AWjm~D-?  
fileFetch.start(); oM)h#8bq  
} bO;(bE m@  
catch(Exception e){e.printStackTrace ();} ~=wC wA|1  
qTB$`f'|$  
HJC(\\~  
} =rd|0K"(r  
4#(ZNP  
9~0^PzTA  
public static void main(String[] args) ;ml 3  
{ `T2$4>!  
new TestMethod(); #$1og=  
} kip`Myw+  
} W{5:'9,  
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