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http断点续传简单实现(java)

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/* BN??3F8C  
**SiteFileFetch.java DJ)Q,l*|N9  
*/ o~<ith$A*  
package NetFox; >@?!-Fy5  
import java.io.*; ~jcdnm]  
import java.net.*; M&auA  
fCC^hB]'  
RLl*@SEi"  
public class SiteFileFetch extends Thread { *K}h >b 1  
Egy#_ RT{  
B?A]0S  
SiteInfoBean siteInfoBean = null; //文件信息Bean )b AOA  
long[] nStartPos; //开始位置 xZbiEDU  
long[] nEndPos; //结束位置 @`"U D  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a}(xZ\n^D;  
long nFileLength; //文件长度 cV8Bl="gqe  
boolean bFirst = true; //是否第一次取文件 O^/z7,  
boolean bStop = false; //停止标志 %DOV)Qc2  
File tmpFile; //文件下载的临时信息 rjk{9u1a"  
DataOutputStream output; //输出到文件的输出流 u*n%cXY;J/  
;5S'?fj  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Q8d-yJs&  
public SiteFileFetch(SiteInfoBean bean) throws IOException |.]sL0; 4Z  
{ 3i\<#{  
siteInfoBean = bean; mO#62e4C  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); M/<>'%sj  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Zw@=WW[Q`p  
if(tmpFile.exists ()) 4v[Zhf4JM  
{ z[vHMJ 0  
bFirst = false; @J~hi\&`  
read_nPos(); LR`]C]  
} MKiP3kt8  
else C[X2]zr  
{ M%{,?a0V  
nStartPos = new long[bean.getNSplitter()]; /[V}   
nEndPos = new long[bean.getNSplitter()]; nC6 ;:uM  
} u9c^:Op  
zDK"Y{  
eHX;*~e6)  
<rQ+ErDA  
} 4eD>DW  
QYB66g:  
qS|ns'[  
public void run() UO~Xzx!e  
{ rl/]Ym4j  
//获得文件长度 pc+'/~  
//分割文件 a+!r5689  
//实例FileSplitterFetch LZ'Y3 *  
//启动FileSplitterFetch线程 G!<-9HA5  
//等待子线程返回 X}f u $2  
try{ %p; 'l  
if(bFirst) a8w/#!^34  
{ "A9qC*6[  
nFileLength = getFileSize(); j'IZetT  
if(nFileLength == -1) sa?Ul)L2  
{ g.,_E4L  
System.err.println("File Length is not known!"); q0t}  
} eVRPjVzQ'Q  
else if(nFileLength == -2) 9_Ws8nE  
{ ov$S   
System.err.println("File is not access!"); wk9qyv<  
} ]K0G!TR<  
else j 3t,Cx  
{ _48@o^{  
for(int i=0;i<nStartPos.length;i++) Y[~Dj@Q<  
{ zm~sq_=^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |#i|BVnoE  
} <>71;%e;'  
for(int i=0;i<nEndPos.length-1;i++) +eUWf{(_  
{ i8nzPKF2$3  
nEndPos = nStartPos[i+1]; BbC aIt  
} bCfw,V{sce  
nEndPos[nEndPos.length-1] = nFileLength; T8t_+| ( G  
} 07 E9[U[  
} d_] sV4[  
pP|LSr Y!  
bmP2nD6  
//启动子线程 0wE)1w<C~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; O'.sK pXe  
for(int i=0;i<nStartPos.length;i++) xf|vz|J?y  
{ *]K/8MbiF  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o=)["V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Dkyw3*LCn%  
nStartPos,nEndPos,i); ;N?raz2mEi  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @3v[L<S{  
fileSplitterFetch.start(); -Cc2|~n  
} g3*J3I-O  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Va-.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1e)5D& njS  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -qs R,H  
nEndPos = " + nFileLength); L"[>tY  
// fileSplitterFetch[nPos.length-1].start(); 3uy^o  
0 zn }l6OS  
qe_qag9  
//等待子线程结束 {oVoN>gp  
//int count = 0; Qj3l>O  
//是否结束while循环 =N^j:t  
boolean breakWhile = false; U UYx-x  
f?BApm  
H[J5A2b  
while(!bStop) ., =\/ C<  
{ d>gN3}tT  
write_nPos(); .|c=]_{  
Utility.sleep(500); *-,jIaL;  
breakWhile = true; H$)__V5I,q  
{^A,){uX]  
S4C4_*~Vd  
for(int i=0;i<nStartPos.length;i++) njGZ#{"eC  
{ q]rqFP0C  
if(!fileSplitterFetch.bDownOver) e13' dCG  
{ 78h!D[6  
breakWhile = false; AYHefAF<w  
break; Wagb|B\  
} S]g`Ds<  
} 9Ac4'L  
if(breakWhile) bFB.hkTP  
break; ,7os3~Mk9  
e\95X{_'  
X$(YCb  
//count++; +2JC**)I  
//if(count>4) ]&_z@Z.i  
// siteStop(); e3=-7FU  
} P;V5f8r?  
r}M2t$nv  
VpyqVbx1  
System.err.println("文件下载结束!"); EXizRL-9o  
} %d^ =$Q  
catch(Exception e){e.printStackTrace ();} LA4,o@V`  
} jn._4TQ*}  
d Z P;f^^  
`%$l b:e  
//获得文件长度 u!TMt8+c  
public long getFileSize() ;.I,R NM  
{ lnWs cb3t  
int nFileLength = -1; =y]F cxF  
try{ a"!r]=r  
URL url = new URL(siteInfoBean.getSSiteURL()); s0/y> ok  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q7(I'  
httpConnection.setRequestProperty("User-Agent","NetFox"); XGSgx  
WKB K)=  
I'c rH/z9  
int responseCode=httpConnection.getResponseCode(); H]PEE!C;xC  
if(responseCode>=400) 4O '%$6KR(  
{ fp2uk3Bm[  
processErrorCode(responseCode); WVdF/H  
return -2; //-2 represent access is error [;$9s=:[  
} ;t \C!A6  
KvNw'3Ua  
i'MpS  
String sHeader; H|s,;1#  
5 NN`tv  
+P|Z1a -jB  
for(int i=1;;i++) 7CSd}@71\  
{ u iR[V~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); zw}Wm4OH  
//Utility.log(in.readLine()); G~{#%i  
sHeader=httpConnection.getHeaderFieldKey(i); SGUZ'}  
if(sHeader!=null) Z ItS(o J.  
{ -m_H]<lWZ  
if(sHeader.equals("Content-Length")) i _YJq;(  
{ 2+}hsGnp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); IP+.L]S  
break; *DuP~8  
} (3QG  
} >"<<hjKJ  
else dH~i  
break; [w?v !8l  
} Y~P* !g  
} q4]Qvf>  
catch(IOException e){e.printStackTrace ();} `Oe"s_O#  
catch(Exception e){e.printStackTrace ();} *ulkqpO  
H'x) [2  
}HxC ~J"  
Utility.log(nFileLength); W3]?>sLE*  
6GsB*hW  
kA{eT  
return nFileLength; E=RX^ 3+}  
} gi JjE  
j7 \y1$w  
f!13Ob<8r  
//保存下载信息(文件指针位置) P*3PDa@  
private void write_nPos() * %w8bB  
{ 2'7)D}p  
try{ UY/qI%#L#,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); FV5~sy  
output.writeInt(nStartPos.length); 2i~zAD'  
for(int i=0;i<nStartPos.length;i++) N&]_U%#Q  
{ +J  <<me4  
// output.writeLong(nPos); 4C`p`AQqpQ  
output.writeLong(fileSplitterFetch.nStartPos); DNGj81'c  
output.writeLong(fileSplitterFetch.nEndPos); x?n13C  
} +W^$my)<  
output.close(); 7qEc9S@  
} df7 xpV  
catch(IOException e){e.printStackTrace ();} oWV^o8& GH  
catch(Exception e){e.printStackTrace ();} ;[!W*8.c  
} ?.6fVSa  
o>@9[F,h+  
Ht&%`\9s  
//读取保存的下载信息(文件指针位置) _7N^<'B  
private void read_nPos() gbjql+Mx+  
{ N5Ih+8zT  
try{ (i>bGmiN  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); lj"72   
int nCount = input.readInt(); ' qN"!\  
nStartPos = new long[nCount]; v<V9Z <ub  
nEndPos = new long[nCount]; C$7dmGjZ  
for(int i=0;i<nStartPos.length;i++) LseS8F/q  
{ ]C5/-J,F  
nStartPos = input.readLong(); 2M*84oh8P  
nEndPos = input.readLong(); 7"s8G 7  
} [Q:mLc  
input.close(); vl:V?-sY  
} k_](u91  
catch(IOException e){e.printStackTrace ();} C~8;2/F7  
catch(Exception e){e.printStackTrace ();} f<Xi/ (  
} Ue!~|:  
#Y<(7  
TRku(w1f  
private void processErrorCode(int nErrorCode) N\W4LO6  
{ 4<q'QU#l<  
System.err.println("Error Code : " + nErrorCode); gYW  
} TUM7(-,9  
ZGC*BP/  
3#~w#Q0%  
//停止文件下载 +JPHQx'W  
public void siteStop() f~v@;/HL  
{ nW!pOTJq21  
bStop = true; &ngG_y8}&  
for(int i=0;i<nStartPos.length;i++) (VB-5&b  
fileSplitterFetch.splitterStop(); NG\^>.8  
">!<OB  
o 76QQ+hP  
} OE5JA8/H  
} [hXnw'Im/  
//负责部分文件的抓取 F8>J(7On  
**FileSplitterFetch.java K&UTs$_cI  
*/ $pfN0/`(  
package NetFox; Z{rD4S @^  
,Ep41v;T%`  
LRKl3"M  
import java.io.*; v)-:0 f  
import java.net.*; y4`uU1=  
)~=g}&  
N^xk.O_TO  
public class FileSplitterFetch extends Thread { AlhPT (  
} DQ KfS  
P= nu&$;  
String sURL; //File URL ^^{7`X u  
long nStartPos; //File Snippet Start Position * $v`5rP  
long nEndPos; //File Snippet End Position CK#SD|~:  
int nThreadID; //Thread's ID l t{yo\  
boolean bDownOver = false; //Downing is over e2vL UlL8  
boolean bStop = false; //Stop identical @V71%D8{  
FileAccessI fileAccessI = null; //File Access interface #/2W RN1L  
XS`=8FQ  
6}^6+@LG  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException uH=^ILN.  
{ ;SVAar4r  
this.sURL = sURL; !1fAW! 8  
this.nStartPos = nStart; }8)iFP&"  
this.nEndPos = nEnd; sq1v._^s  
nThreadID = id; >%Nqgn$V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 khS >  
} ^K`Vqo  
KdU&q+C^  
@zAav>  
public void run() 6qq{JbK  
{ :?J0e4.]  
while(nStartPos < nEndPos && !bStop) 8 rA'd  
{ {aVL3QU  
oC >l|?h,  
pjrzoMF  
try{ 4j VFzO%.  
URL url = new URL(sURL); PYJ8\XZ1_N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5`O af\S  
httpConnection.setRequestProperty("User-Agent","NetFox"); v]e6CZwo  
String sProperty = "bytes="+nStartPos+"-"; >TB Rp,;r  
httpConnection.setRequestProperty("RANGE",sProperty); m8C scC Z}  
Utility.log(sProperty); Mi2l BEu,  
uZkh.0yB  
o}VW%G"  
InputStream input = httpConnection.getInputStream(); IPEJ7 n49  
//logResponseHead(httpConnection); O\ph!?L  
Hsvu&>[`S  
XR.Sm<A[  
byte[] b = new byte[1024]; 02 6|u|R  
int nRead; J'4V_Kjg-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Az4a|.  
{ NkL>ru!b9  
nStartPos += fileAccessI.write(b,0,nRead); D?6ah=:&R  
//if(nThreadID == 1) J4>k9~q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]] Jg%}o  
} _{f7e^;  
GK\`8xWE  
J6W"t  
Utility.log("Thread " + nThreadID + " is over!"); +VdC g_  
bDownOver = true; @-H D9h  
//nPos = fileAccessI.write (b,0,nRead); _ tO:,%dL  
} `8<h aU  
catch(Exception e){e.printStackTrace ();} Kta7xtu  
} 4M{]YZMw8  
} fkW TO"f-  
@l^BW*BCo  
6O# xV:Uc<  
//打印回应的头信息 qGH\3g-  
public void logResponseHead(HttpURLConnection con) HI*j6H?\  
{ $ ";NS6 1  
for(int i=1;;i++) G@I/Dy  
{  :bBMy\(u  
String header=con.getHeaderFieldKey(i); KQv97#n1  
if(header!=null) Ub9p&=]h  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `zBQ:_3J_  
Utility.log(header+" : "+con.getHeaderField(header)); BkcA_a:W  
else |*[#Iii'  
break; ds|L'7  
} P K9BowlW  
} Ki{]5Rz  
'H.,S_v1x  
PS3%V_2  
public void splitterStop() ?84B0K2N s  
{ )AoF-&,w  
bStop = true; t $yt8#Tk  
} ?PSVVU q,Z  
jZLD^@AP  
1Z| {3W  
} gW(7jFl  
nD/; Gq  
(TQhO$,  
/* C#Y_La  
**FileAccess.java u~VvGLFf5,  
*//文件访问(定位,写) c"x-_Uk  
package NetFox; 8 DE%ot  
import java.io.*; 3El5g0'G  
B9(e"cMm  
_8eN^oc%  
public class FileAccessI implements Serializable{ ZclZD{%8J  
BiI}JEp4o  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0CFON2I  
RandomAccessFile oSavedFile; syR +;  
long nPos;  #:st>V_h  
Y,;$RV@g  
#k*P/I~  
public FileAccessI() throws IOException xY,W[?3CY  
{ x;L.j7lzA;  
this("",0); 'hn=X7  
} /ig'p53jL  
1j":j%9M  
+kN/-UsB  
public FileAccessI(String sName,long nPos) throws IOException QYj8c]8f  
{ w +~,Mv\  
oSavedFile = new RandomAccessFile(sName,"rw"); x8q3 Njr  
this.nPos = nPos; |r%lJmBB  
oSavedFile.seek(nPos); xHo iu$i6  
} $b=4_UroS  
s`E^1jC  
u^NZsuak  
public synchronized int write(byte[] b,int nStart,int nLen) dOfEEqPI  
{ &Y/Myh[P  
int n = -1; Fo86WP}  
try{ vx&r  
oSavedFile.write(b,nStart,nLen); @& vtY._  
n = nLen; 2^.qKY@g@  
} ZN]LJ4|xu  
catch(IOException e) Am&PH(}L  
{ e6JT|>9A7  
e.printStackTrace (); n 0*a.  
} f+o%N  
Pk 6l*+"r<  
B[Gl}(E  
return n; lmjoSINy  
} @ 4%a  
3+` <2TP  
"spAYk\  
} _Boe"   
Sy?O(BMo  
L dyTB@  
/* B}y`E <  
**SiteInfoBean.java (ev(~Wc  
*/ > lg-j-pV  
package NetFox; O?I~XM'S  
">V.nao  
TtZ '~cGR  
public class SiteInfoBean { bw\a\/Dw  
(&y~\t] H  
)n&@`>vm  
private String sSiteURL; //Site's URL Spt]<~  
private String sFilePath; //Saved File's Path =5QP'Qt{O  
private String sFileName; //Saved File's Name 6JYVC>i  
private int nSplitter; //Count of Splited Downloading File w?LDaSz\t  
l0%qj(4`6&  
N-g=_86C"  
public SiteInfoBean() [LHx9(,NM  
{//nSplitter的缺省值为5 A^9RGz4=  
//default value of nSplitter is 5 %1Pn;bUU!  
this("","","",5); hb_J. Q  
} ?k7z 5ow  
?9)-?tZ^Q  
wh~g{(Xvq  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .7"]/9oB  
{ |z`kFil%  
sSiteURL= sURL; Eoo[)V#x{  
sFilePath = sPath; v|r=}`k=  
sFileName = sName; viP.G/(\]  
this.nSplitter = nSpiltter; t"]+}]O  
hCcAAF*I;5  
#A RQB2V  
} |*w}bT(PfR  
`?H yDny  
uR:@7n  
public String getSSiteURL() @},25"x)  
{ p[zKc2TPk  
return sSiteURL; ?k*%r;e>  
}  3~mi  
9 Z 5!3  
!Xzne_V<  
public void setSSiteURL(String value) JQt Bt2  
{ tf5h/:  
sSiteURL = value; s$,gM,|cK  
} #J,?oe=<4  
N5SePA\ ,?  
*C*'J7  
public String getSFilePath() yX'f"*  
{ uV@#;c4  
return sFilePath; R zOs,  
} /7)l22<  
L/U^1=Wi*O  
\:To>A32  
public void setSFilePath(String value) dV( "g],  
{ $z>L $,c>  
sFilePath = value; 2 ;z~xR  
} E W {vF|  
zP8a=Iv  
nSM8o<)H  
public String getSFileName() %rmn+L),;  
{ \.`;p  
return sFileName; Pr%Y!|  
} K9*vWoP'  
^4\h Z  
c8^M::NI  
public void setSFileName(String value) $@[`v0y*  
{ w4m)lQM  
sFileName = value; <h*r  
} xDU{I0M  
4NY}=e5  
sr=~U q{g  
public int getNSplitter() gNsas:iGM  
{ /mM#nS  
return nSplitter; o<Esh;;*nm  
} -Dx_:k|k  
\x,q(npHi  
{c;][>l  
public void setNSplitter(int nCount) r? w^#V  
{ N '8u}WO  
nSplitter = nCount; Y M <8>d  
} vH^6O:V  
} 'K L" i  
nI63Ns  
(&W&1KT  
/* UcHe"mn  
**Utility.java Cm~Pn "K_]  
*/ g p2S   
package NetFox; 2+2Gl7" s  
bI_6';hq!  
v `a:Lj  
public class Utility { sUCI+)cM3  
cIL I%W1  
T ke3X\|  
public Utility() ~6)A/]6  
{ Mx3MNX /  
7O=N78M  
bp>-{Nv  
} &^v5 x"  
pn:) Rq0  
//线程睡眠 X{ZcJ8K  
public static void sleep(int nSecond) Z8X=Md8=  
{ ;V=Y#|o  
try{ bc?\lD$ $  
Thread.sleep(nSecond); {Tps3{|wt  
} pdz_qj!Z  
catch(Exception e) d3m!34ml  
{ '@ $L}C#OI  
e.printStackTrace (); o*[n[\cR  
} kK0.j)(  
} Q|DVB  
e={X{5z0  
//日志 xzZ2?z Wi  
public static void log(String sMsg) T uk:: .jD  
{ H8'q Y  
System.err.println(sMsg); B#+0jdF;  
} o#D;H[' A  
Mx7  
va`/Dp)M  
public static void log(int sMsg) M/O Y "eL  
{ m#i5}uHHg  
System.err.println(sMsg); 8NE+G.:G  
} >{v,H Oxl  
} wX!q dII)  
Z~?1xJ&  
]#7{ x  
/* QGR}`n2D  
**TestMethod.java 0Z m^6T  
*/ gXNlnh%?S  
package NetFox; \W,,@ -  
bPlqS+ai_  
@PaOQ@  
public class TestMethod { T4M"s;::1  
,w9:)B7  
j$<sq  
public TestMethod() Z7="on4  
{ ///xx/weblogic60b2_win.exe \Nvu[P  
try{ cbton<r~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?ufX3yia  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); eTeZ^G  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ef Moi'v  
fileFetch.start(); l\HLlwYO  
} Q{:5gh  
catch(Exception e){e.printStackTrace ();} c*k%r2'  
]T?Py)  
8JFns-5  
} <Lt%[dn  
yx@%x?B  
E .'v,GYe  
public static void main(String[] args) At0ahy+  
{ _s1pif  
new TestMethod(); Jp d|<\Ml  
} e #5LBSP  
} 'o!{YLJ fM  
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