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http断点续传简单实现(java)

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/* x;L.j7lzA;  
**SiteFileFetch.java  01;  
*/ iD-,C`  
package NetFox; u iEAi  
import java.io.*; oGa8#>  
import java.net.*; w +~,Mv\  
x8q3 Njr  
|r%lJmBB  
public class SiteFileFetch extends Thread { xHo iu$i6  
C. rLog#  
VvJ]*D+e  
SiteInfoBean siteInfoBean = null; //文件信息Bean *4oj' }  
long[] nStartPos; //开始位置 tH\ aHU[  
long[] nEndPos; //结束位置 ;4] sP^+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 k~+(X|!5w  
long nFileLength; //文件长度 }'.k  
boolean bFirst = true; //是否第一次取文件 9;B6<`e/U  
boolean bStop = false; //停止标志 h..D1(M  
File tmpFile; //文件下载的临时信息 r|W 2I,P  
DataOutputStream output; //输出到文件的输出流 5o P 3 1  
:2_8.+:  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) yw3E$~k  
public SiteFileFetch(SiteInfoBean bean) throws IOException }jWZqIqj  
{ S85}&\m&4  
siteInfoBean = bean; Ebk_(Py\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]BiLLDz(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); map#4\  
if(tmpFile.exists ()) ck"lX[d1  
{ WUnmUW[/  
bFirst = false; f#3U,n8:  
read_nPos(); asQXl#4r  
} @ a?^2X^  
else ; M%n=+[O  
{ tF@hH}{;  
nStartPos = new long[bean.getNSplitter()]; 6x$1En  
nEndPos = new long[bean.getNSplitter()]; }q~M$  
} vn0}l6n3s  
*#n?6KqZ  
4gRt^T-?  
RO10$1IW.2  
} u_~*)w+mS@  
(" ,(@nS  
Oi~ ]~+2  
public void run() E)h&<{%  
{ X\dPQwasM  
//获得文件长度 ~c*$w O\  
//分割文件 8ezdU"  
//实例FileSplitterFetch Rl2*oOVz  
//启动FileSplitterFetch线程 W@( EEMhw  
//等待子线程返回 O%KP,q&}Y  
try{ & &\HE7*  
if(bFirst) O=C z*j  
{ |re>YQ!zd  
nFileLength = getFileSize(); RO?%0-6O&  
if(nFileLength == -1) zYW+Goz/C  
{ %Gk?f=e  
System.err.println("File Length is not known!"); (g8<"< N?  
} =ZaTD-%id  
else if(nFileLength == -2) ee0)%hc1t  
{ vg6 ' ^5S7  
System.err.println("File is not access!"); jZX2)#a!  
} hCcAAF*I;5  
else #A RQB2V  
{ V&75n.L  
for(int i=0;i<nStartPos.length;i++) j~)GZV  
{ uR:@7n  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); MI,b`pQ  
} Q{~WWv  
for(int i=0;i<nEndPos.length-1;i++) vA r fsgk  
{ =d{B.BP(  
nEndPos = nStartPos[i+1]; 9 Z 5!3  
} !Xzne_V<  
nEndPos[nEndPos.length-1] = nFileLength; ? !dy  
} DnZkZ;E/  
} s$,gM,|cK  
#J,?oe=<4  
N5SePA\ ,?  
//启动子线程 *C*'J7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jM'kY|<g;  
for(int i=0;i<nStartPos.length;i++) uV@#;c4  
{ R zOs,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S-$N!G~!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :E>" z6H  
nStartPos,nEndPos,i); tlnU2TT_f  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *QIlh""6  
fileSplitterFetch.start(); 5ZXP$.  
} D[NJ{E.{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1@}`dc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a->;K+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @Weim7r  
nEndPos = " + nFileLength); 0^L>J "o  
// fileSplitterFetch[nPos.length-1].start(); 007(k"=oV  
5a PPq~%  
~T{^7"q\  
//等待子线程结束 ~'[0-_]=f  
//int count = 0; m4<5jC`-M  
//是否结束while循环 [f?fA[, [  
boolean breakWhile = false; X(`wj~45VX  
);]9M~$  
`k 5'nnyP  
while(!bStop) J ^y1=PM  
{ IYo{eX~=  
write_nPos(); =u5a'bp0;;  
Utility.sleep(500); 9uNkd2 #  
breakWhile = true; kma)DW  
/5l"rni   
!Rq.L  
for(int i=0;i<nStartPos.length;i++) 1TagQ  
{ <yw6Om:n<  
if(!fileSplitterFetch.bDownOver) xE2sb*  
{ &RzkM4"  
breakWhile = false; =nQgS.D  
break; 'nrX RDb  
} gB;5&;T:  
} #%;QcDXRe  
if(breakWhile) 5 +Ei! E89  
break; eYN =?  
/*zngp @  
)nK-39,G  
//count++; I:ag}L8`  
//if(count>4) r}-si^fo;  
// siteStop(); e#+u8LrN  
} '\ MYC8"  
sUCI+)cM3  
_\d[`7#  
System.err.println("文件下载结束!"); )tq&l>0h  
} _XO3ml\x@  
catch(Exception e){e.printStackTrace ();} Mj guH5Uy  
} JBYmy_Su  
%z0;77[1I  
2~*J<iO&l  
//获得文件长度 C V{kP8#  
public long getFileSize() . paA0j  
{ 1kd\Fq^z$  
int nFileLength = -1; ] WsQ=  
try{ ]~Su  
URL url = new URL(siteInfoBean.getSSiteURL()); Aa.eu=@I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *t)Y@=k3>  
httpConnection.setRequestProperty("User-Agent","NetFox"); p-6Y5$Y  
\-]zXKl2k  
?=bqya"Y  
int responseCode=httpConnection.getResponseCode(); va>u1S<lO  
if(responseCode>=400) 6/%dD DU  
{ kK0.j)(  
processErrorCode(responseCode); Q|DVB  
return -2; //-2 represent access is error e={X{5z0  
} xzZ2?z Wi  
e2~$=f-  
bvxol\7;  
String sHeader; @d+NeS  
,EE,W0/zzM  
YR 5C`o  
for(int i=1;;i++) P1r)n{;  
{ vky@L!&,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); D <16m<b  
//Utility.log(in.readLine()); ,esryFRG  
sHeader=httpConnection.getHeaderFieldKey(i); K4G43P5q`  
if(sHeader!=null) B$ Z%_j&  
{ Qb.Ve7c  
if(sHeader.equals("Content-Length")) QGR}`n2D  
{ ag_RKlM3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); k Y}r^NaQA  
break; W<QMUu  
} q)m0n237P  
} RjcU0$Hi  
else )V6Bzn}9  
break; DV8b<)  
} +2KYtyI  
} Ao0p=@Y  
catch(IOException e){e.printStackTrace ();} ~$WBcqo  
catch(Exception e){e.printStackTrace ();} c\J?J>xz  
!Qqi%  
+nz6+{li\  
Utility.log(nFileLength); 61[ 8I},V  
+.EP_2f9  
Az`c? W%  
return nFileLength; UdiogXZ  
} ,:E*Mw:  
__3s3YG  
NrVE[Z#  
//保存下载信息(文件指针位置) )'+ tb\g  
private void write_nPos() G2 E4  
{ 9W7 ljUg  
try{ Wq+a5[3"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wm'a)B?  
output.writeInt(nStartPos.length); t1Zcr#b>  
for(int i=0;i<nStartPos.length;i++) ~YH'&L.O  
{ 3w>S?"W#  
// output.writeLong(nPos); kL7n`o  
output.writeLong(fileSplitterFetch.nStartPos); #Ns]l<  
output.writeLong(fileSplitterFetch.nEndPos); ]UMt  
} f*:DH4g }B  
output.close(); |h7 d #V>  
} &2P+9j>  
catch(IOException e){e.printStackTrace ();} M3 TsalF  
catch(Exception e){e.printStackTrace ();} xk#q_!(j  
} w|k?2 ?&  
~fht [S?@M  
v>[U*E  
//读取保存的下载信息(文件指针位置) >,9ah"K_x  
private void read_nPos() <27:O,I  
{ - K@mjN  
try{ VqIzDs  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); OxC8xB;`  
int nCount = input.readInt(); 1Mtm?3Pt  
nStartPos = new long[nCount]; q;)+O#CR  
nEndPos = new long[nCount]; 4ZX6=-u^  
for(int i=0;i<nStartPos.length;i++) sU=7)*$  
{ w<P$)~6  
nStartPos = input.readLong(); \{@n >Mh  
nEndPos = input.readLong(); Xa xM$  
} 5fT"`FL?  
input.close(); gB)Cmw*  
} .,9e~6}  
catch(IOException e){e.printStackTrace ();} :f/T $fa*  
catch(Exception e){e.printStackTrace ();} "C/X#y   
} ,O'#7Dj  
nn?h;KzB  
XzD+#+By  
private void processErrorCode(int nErrorCode) l} =@9A@  
{ b)(rlX  
System.err.println("Error Code : " + nErrorCode); L|*0 A=6  
} Gpb<,v_3  
F*, e,s  
k0(_0o  
//停止文件下载 |lG7/\A  
public void siteStop() e a3f`z  
{ SmUj8?6"  
bStop = true; ;]PP +h  
for(int i=0;i<nStartPos.length;i++) ^Mmsja5K  
fileSplitterFetch.splitterStop(); Oj,v88=  
51Q m2,P1^  
gy*c$[NS$  
} %jErLg  
} 8JFvz(SK>  
//负责部分文件的抓取 4/?@ %  
**FileSplitterFetch.java ec sQshR  
*/ Re<@ .d  
package NetFox; |6O7_U#q  
m5_  
<C<z#M'`  
import java.io.*; ~#];&WE  
import java.net.*; B~h3naSe  
_g2"D[I%  
*mjPNp'3{m  
public class FileSplitterFetch extends Thread { N!~5S`  
W' Y?X]xr  
}Sr=|j  
String sURL; //File URL AeR*79x  
long nStartPos; //File Snippet Start Position bn#'o(Lp  
long nEndPos; //File Snippet End Position p&$O}AX|  
int nThreadID; //Thread's ID fW z=bJ"V  
boolean bDownOver = false; //Downing is over eq6>C7.$  
boolean bStop = false; //Stop identical VxAG= E  
FileAccessI fileAccessI = null; //File Access interface V]5MIiNl  
oiTSpd-  
h3rVa6cxM  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException QF4)@ r{2x  
{ 9q]n &5  
this.sURL = sURL; ?P%-p  
this.nStartPos = nStart; % 4Gt^:J"  
this.nEndPos = nEnd; d^+0=_[PmK  
nThreadID = id; Mpx98xcO  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Kn*LwWne  
} 5kik+  
 &Sdf0"  
[C`LKA$t  
public void run() <]f{X<ef  
{ cw/E?0MWb  
while(nStartPos < nEndPos && !bStop) +'0V6 \y  
{ O)8$aAJ)V  
&[7z:`+Y##  
AaLbJYuKd  
try{ rcAPp  
URL url = new URL(sURL); ;Xl {m`E+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FI"KJk'  
httpConnection.setRequestProperty("User-Agent","NetFox"); M3VTzwuf^S  
String sProperty = "bytes="+nStartPos+"-"; `>Ms7G9S~e  
httpConnection.setRequestProperty("RANGE",sProperty); -x VZm8y  
Utility.log(sProperty); W P9PX  
hYbaVE  
nt_FqUJ  
InputStream input = httpConnection.getInputStream(); W+I""I*mV  
//logResponseHead(httpConnection); bk|?>yd  
!<vy!pXg  
/d*[za'0  
byte[] b = new byte[1024]; p5aqlYb6r  
int nRead; $U4[a:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &>xz  
{ ]YrgkC35  
nStartPos += fileAccessI.write(b,0,nRead); 9T_fq56Oh6  
//if(nThreadID == 1) rtdEIk  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  Pm"nwm  
}  OK(xG3T  
~X(2F#{<{  
L0;XzZ S  
Utility.log("Thread " + nThreadID + " is over!"); ~5o2jTNy`p  
bDownOver = true; F<4>g+Ag  
//nPos = fileAccessI.write (b,0,nRead); D]twid~OS  
} K]&i9`>N   
catch(Exception e){e.printStackTrace ();} }Ud'j'QMy  
} Ce/D[%  
} /V }Z,'+  
FA{'Ki`  
meYGIP:n  
//打印回应的头信息 v, !`A!{D  
public void logResponseHead(HttpURLConnection con) *G8Z[ht%r  
{ Zg9VkL6Z6  
for(int i=1;;i++) 5fy{!  
{ uN=f( -"  
String header=con.getHeaderFieldKey(i); aMJJ|iiU  
if(header!=null) vDIsawbHD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); QIfP%,LT  
Utility.log(header+" : "+con.getHeaderField(header)); 88VI _<  
else /*(&Dmt>  
break; D67z6jep(  
} Md&K#)9,(  
} r72zWpF!Ss  
b%].D(qBy  
7ufTmz#j<  
public void splitterStop() `S A1V),~  
{ P2F8[o!<  
bStop = true; _:>t$* _  
} (6i4N2  
40O@a:q*  
q2U?EP{8~  
} 32Wa{LG;2  
a4 mRu|x  
LK<ZF=z]Z  
/* ^O& y ;5  
**FileAccess.java MaLH2?je^n  
*//文件访问(定位,写) 'Hsd7Dpi}  
package NetFox; n5y0$S/ D  
import java.io.*; 11%Zx3  
}:S}jo7  
t$b5,"G1  
public class FileAccessI implements Serializable{ I#'yy7J  
DiskGq@T  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 c`/kx  
RandomAccessFile oSavedFile; Mp(;PbVD  
long nPos; ';m;K (g  
l=L(pS3 ~  
S{Zf}8?6$  
public FileAccessI() throws IOException iI3,q-LA  
{ Z`#XB2,  
this("",0); <B'PB"R3y  
} +U iJWO  
n(.L=VuXn  
\ 0Ba?  
public FileAccessI(String sName,long nPos) throws IOException [<sN "  
{ fNV-_^,R9  
oSavedFile = new RandomAccessFile(sName,"rw"); *;l[|  
this.nPos = nPos; 7=s7dYlu  
oSavedFile.seek(nPos); kG5Uc8 3#G  
} "-\8Y>E  
owwWm1@  
5lyHg{iqD  
public synchronized int write(byte[] b,int nStart,int nLen) %~M#3Ywa  
{ ] G^9PZ-  
int n = -1; l5D4 ?`|  
try{ GcG$>&,  
oSavedFile.write(b,nStart,nLen); xEv?2n@A  
n = nLen; `NNP}O2  
} =}0$|@pl  
catch(IOException e) Gz4LjMQ &  
{ 7eW6$$ju,N  
e.printStackTrace (); C}ASVywc,1  
} Qjd]BX;  
^V7)V)Z;0  
|pBvy1e4)  
return n; t^2$ent  
} :(4q\~  
!r9rTS]  
?X Rl\V  
} !}sF#  
R+2~%|{d  
],{M``]q  
/* U;*O7K=P  
**SiteInfoBean.java ce*?crOV  
*/ Kw2]J)TO  
package NetFox; `6BQ6)7  
Wz#ZkNO  
g`~;"%u7cn  
public class SiteInfoBean { 2wa'WEx  
Io t c>!  
D&pp <  
private String sSiteURL; //Site's URL ..w$p-1  
private String sFilePath; //Saved File's Path " t?44[  
private String sFileName; //Saved File's Name Hz=s)6$ey  
private int nSplitter; //Count of Splited Downloading File *?VB/yO=0  
~6+Um_A_L  
w ~^{V4V  
public SiteInfoBean() or bz`IQc  
{//nSplitter的缺省值为5 JSx[V<7m  
//default value of nSplitter is 5 7PwH&rI  
this("","","",5); Ocz21gl-?`  
} )|#ExyRO  
cQsSJBZ[v5  
]:m4~0^#-(  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MP.ye|i4Q  
{ Kjpsz];  
sSiteURL= sURL; l TVz'ys  
sFilePath = sPath; FC  
sFileName = sName; N34bB>_  
this.nSplitter = nSpiltter; d[*NDMO  
:&LV^ A  
"ZA`Lp;%w  
} _ q AT%.  
~f( #S*Ic  
s>[Oe|`  
public String getSSiteURL() =h|7bYLy  
{  )\kNufP  
return sSiteURL; t~.^92]s|  
} ad9u;uS  
s@Loax6@B  
+UX} "m~W  
public void setSSiteURL(String value) ?}S!8;d  
{ 6WoFf  
sSiteURL = value; wUfPnAD.'  
} E^m)&.+'M  
/<dl"PWkJv  
C;#gy-  
public String getSFilePath() P7REE_<1  
{ }=.C~f]A  
return sFilePath; ca,c+5  
} c{39,oF  
) q/brCq  
xK4E+^ b  
public void setSFilePath(String value) |CK/-UG}  
{ k^K%."INn  
sFilePath = value; B B^81{A  
} SRU#Y8Xv|  
1v<uA9A%[  
W .Al\!Gi  
public String getSFileName() V8b^{}nxt  
{ 1^[]#N-Bu  
return sFileName; R;uP^  
} Q8]S6,pt  
~q}]/0-m  
pW>.3pj  
public void setSFileName(String value) :5jor Vu  
{ 23opaX5V=  
sFileName = value; @V@<j)3P  
} 9WHarv2@  
]eX(K5 A  
7t78=wpLc  
public int getNSplitter() !\5)!B  
{ 'b+ Tio  
return nSplitter; `8TL*.9  
} E~8J<g E  
z5sKV7&\[n  
-qLNs_ _k  
public void setNSplitter(int nCount) %6Y}0>gY  
{ @[n%q.|VB  
nSplitter = nCount; EJJ&`,q  
} B*^QTJ  
} L:jv%;DM  
F$9+WS`c  
2%MS$Fto  
/* +!G)N~o  
**Utility.java MW=rX>tE  
*/ tMo=q7ig  
package NetFox; APU~y5vG (  
k_Lv\'Ok  
HD z"i  
public class Utility { 9'KOc5@l^  
=S\pI  
:z$+leNH\  
public Utility() 8P&z@E{y  
{ Qr?(2t#  
0.1?hb|p5T  
9D yy&$s  
} q@Zeu\T,*#  
nzU0=w}V  
//线程睡眠 9FF  
public static void sleep(int nSecond) ^a#W|-:  
{ 4hn' b[  
try{ RVpo,;:  
Thread.sleep(nSecond); C4|79UG>s  
} j"&Oa&SH  
catch(Exception e) ,ZnL38GW  
{ lnV!Xuf  
e.printStackTrace (); cQ0+kX<  
} cWI7];/d;  
} 5)gC<  
a JQ_V  
//日志 2}5@: cwR+  
public static void log(String sMsg) YCyh+%Q(  
{ mH'om SCz  
System.err.println(sMsg); (]5gYi  
} s]xn&rd_  
`>0(N.'T  
|Lc.XxBkc  
public static void log(int sMsg) 5g2:o^  
{ l585L3i  
System.err.println(sMsg); 0rc'SEl  
} jfZ)  
} _~!c%_  
@rr\Jf""z  
hr g'Z5n  
/* ;]2d%Qt  
**TestMethod.java x0xQFlGk  
*/ IN"6 =2:  
package NetFox; |(9l_e|  
J z-RMX=  
&3P"l.j  
public class TestMethod { c2yZvi  
Angt=q  
-V||1@ |  
public TestMethod() s6I/%R3  
{ ///xx/weblogic60b2_win.exe ) =|8%IrB  
try{ =8 DS~J{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Oq 95zo  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); DF"*[]^[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); So#>x5dL  
fileFetch.start(); z>spRl,dr  
} Kq:vTz&<  
catch(Exception e){e.printStackTrace ();} '8|joj>G=  
U2(mWQ[mO  
\%.&$z3wz  
} *(nu0  
Bo/i =/7%  
8ya|eJ]/L  
public static void main(String[] args) qnw8#!%I  
{ (z%OK[  
new TestMethod(); Qs_]U  
} |PLWF[+t8  
} "T6s;'k  
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