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http断点续传简单实现(java)

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/* "#h/sAIs  
**SiteFileFetch.java +F>erdV  
*/ Z@AN0?,`~o  
package NetFox; m;qqjzy  
import java.io.*; WtXf~ :R  
import java.net.*; V@\u<LO0G  
c<{~j~+  
cs[nFfM  
public class SiteFileFetch extends Thread { *q@3yB}  
$8Z4jo  
S7@/d HN  
SiteInfoBean siteInfoBean = null; //文件信息Bean sWi4+PAM0  
long[] nStartPos; //开始位置 Sae*VvT6  
long[] nEndPos; //结束位置 &4*f28 s  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <y#@v  G  
long nFileLength; //文件长度 N37CAbw0  
boolean bFirst = true; //是否第一次取文件 CX ; m8  
boolean bStop = false; //停止标志 H;+98AIy`  
File tmpFile; //文件下载的临时信息 ^,J>=>,1\  
DataOutputStream output; //输出到文件的输出流 29&F_  
1k{H,p7  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ?/(*cA  
public SiteFileFetch(SiteInfoBean bean) throws IOException QoMa+QTuc  
{ 9Fg:   
siteInfoBean = bean; ={jj'X9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5D mSgP:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); biU ?>R  
if(tmpFile.exists ()) M7YbRl  
{ =>O{hT ^F  
bFirst = false; *=Ma5J.  
read_nPos(); & sXMB  
} : z\||f  
else kZfj"+p_S  
{ wBEBj7(y  
nStartPos = new long[bean.getNSplitter()]; FMitIM*]   
nEndPos = new long[bean.getNSplitter()]; .Vs|&c2im  
} t&IWKu#  
>;}(? +|f  
X9rao n  
'"h}l`  
} _<?z-K_;I  
T ^ #1T$  
Pu'lp O  
public void run() xFA`sAucr  
{ !yz3:Yzu  
//获得文件长度 IU"8.(;o  
//分割文件 ly@%1  
//实例FileSplitterFetch x6vkd%fCj  
//启动FileSplitterFetch线程 R?J8#JPXD  
//等待子线程返回 Q v},X~^R  
try{ g9IIC5  
if(bFirst) JtF)jRB0,  
{ 0QEcJ]Qb8  
nFileLength = getFileSize(); i;:}{G<  
if(nFileLength == -1) &7Xsn^opku  
{ ${97G#  
System.err.println("File Length is not known!"); $-(lp0\*  
} _6L'}X$)N  
else if(nFileLength == -2) YI]/gWeu  
{ %2beoH'  
System.err.println("File is not access!"); |{rhks~  
} 9MbF:  
else 4%6@MQ[  
{ 0;w84>M  
for(int i=0;i<nStartPos.length;i++) Hdjp^O!  
{ \JP9lJ3<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); zY].ZS=7  
} .m xc~  
for(int i=0;i<nEndPos.length-1;i++) %PPkT]~\  
{ 2Ic)]6z R  
nEndPos = nStartPos[i+1]; s,M]f,T  
} 8/~@3-9EK  
nEndPos[nEndPos.length-1] = nFileLength; eUD 5 V  
} m`4N1egCt  
} KSU hB  
af/0e}-  
J@rBrKC  
//启动子线程 }t1 q5@QU  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D<[kbt 5^7  
for(int i=0;i<nStartPos.length;i++) eGWwPSIp  
{ "M,Hm!j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =~q$k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `Y, Rk  
nStartPos,nEndPos,i); NYR:dH]N~d  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .{(gku>g(  
fileSplitterFetch.start(); #=Whh 9-d  
} >&T J  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $4]4G=o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xg;F};}5$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;U?323Z  
nEndPos = " + nFileLength); rgEN~e'  
// fileSplitterFetch[nPos.length-1].start(); >B.KI}dE  
uY3?(f#  
nr&9\lG]G  
//等待子线程结束 W^eQ}A+Z  
//int count = 0; a24(9(yh  
//是否结束while循环 +;q` A 1  
boolean breakWhile = false; /KlSI<T@  
p;mV?B?oAQ  
BNixp[Hc  
while(!bStop) ^Jc|d,u;s  
{ OSwum!hzN  
write_nPos(); On,z# A  
Utility.sleep(500); %)e&"mq!|  
breakWhile = true; NkAu<> G _  
LfvRH?<W  
'Xasd3*Py  
for(int i=0;i<nStartPos.length;i++) t ;y@;?~  
{ O44Fj)  
if(!fileSplitterFetch.bDownOver) hKe ms3  
{  3X9  
breakWhile = false; G(1_P1  
break; V}h)e3X  
} ) gxN' z  
} :S+Bu*OyH  
if(breakWhile) 0.B'Bvn=s2  
break; 1W7ClT_cQ  
"_\77cqpTh  
[6nN]U~Y  
//count++; \WZSY||C|_  
//if(count>4) Zy>y7O(,  
// siteStop(); M2A_T.F=H  
} 98CS|NEe  
c3O&sa V!  
%KR2Vlh0  
System.err.println("文件下载结束!"); NHhKEx0Gtu  
} YIHGXi<"n  
catch(Exception e){e.printStackTrace ();} F*y7 4j,  
} I0_>ryA  
Z_Y gV:jc  
_ujhD  
//获得文件长度 yz%o?%@  
public long getFileSize() Yb'%J@T}  
{ v/,,z+%-  
int nFileLength = -1; "[CR5q9Pr  
try{ gc W'  
URL url = new URL(siteInfoBean.getSSiteURL()); YOY2K%o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >{"E~U  
httpConnection.setRequestProperty("User-Agent","NetFox"); = @lM*  
xBE}/F$ 45  
SYgkYR  
int responseCode=httpConnection.getResponseCode(); M4t:)!dji?  
if(responseCode>=400) pwNF\ ={  
{ QPB ^%8  
processErrorCode(responseCode); V:lKF')  
return -2; //-2 represent access is error 2rM/kF >g  
} IG!(q%Gf  
 y`pgJO  
{7EpljH@  
String sHeader; kU{a!ca4  
,/dW*B  
?4_ME3$t  
for(int i=1;;i++) $WsyAUl  
{ 3k:`7E.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1#|qT7  
//Utility.log(in.readLine()); W O'nW  
sHeader=httpConnection.getHeaderFieldKey(i); 'lOpoWDL  
if(sHeader!=null) c']m5q39'  
{ ZU l-&P_X  
if(sHeader.equals("Content-Length")) ye4GHAm,p  
{ iz27yXHZ~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ziv*4  
break; p,3}A( >  
} 352RJC  
} Dp?lgw  
else ,S&p\(r.  
break; 4!-/m7%eF  
} ah#jvp  
} +*wo iSD  
catch(IOException e){e.printStackTrace ();} :bq UA(k  
catch(Exception e){e.printStackTrace ();} HHT8_c'CC#  
U(hIT9  
.cr<.Ov  
Utility.log(nFileLength); {gB9EGY  
K#R|GEwr  
6U1_Wk?   
return nFileLength; 2F/oWt|w?  
} ~eXI}KhBw6  
$?DEO[p.  
:b,An'H  
//保存下载信息(文件指针位置) n/% M9osF  
private void write_nPos() )hD77(c  
{ D_BdvWSxj  
try{ {O4&HW%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); UXOf  
output.writeInt(nStartPos.length); %kuUQ%W1  
for(int i=0;i<nStartPos.length;i++) +)_#j/  
{ jPs{Mr<  
// output.writeLong(nPos); b.cBg.a  
output.writeLong(fileSplitterFetch.nStartPos); 5 axt\  
output.writeLong(fileSplitterFetch.nEndPos); H?;@r1ZAn  
} u0%bv\$m  
output.close(); Wp^ A.  
} af&P;#U  
catch(IOException e){e.printStackTrace ();} O ]t)`+%q  
catch(Exception e){e.printStackTrace ();}  }D!o=Mg^  
} 5m?9O7Pg  
Q5*"t*L!N  
 ">q?(i\  
//读取保存的下载信息(文件指针位置) P&*e\"{  
private void read_nPos() 88l{M[B2  
{ /mK]O7O7  
try{ A $l  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3o#K8EL  
int nCount = input.readInt(); eyos6Qi  
nStartPos = new long[nCount]; 72= 4#  
nEndPos = new long[nCount]; =h/61Bl3  
for(int i=0;i<nStartPos.length;i++) cea e~  
{ 8TYoa:pZ  
nStartPos = input.readLong(); <m%ZDOMa  
nEndPos = input.readLong(); ]G,BSttD  
} ozl>Au  
input.close(); w=[ITQ|W%  
} {&nDm$KTD  
catch(IOException e){e.printStackTrace ();} m(CsO|pz  
catch(Exception e){e.printStackTrace ();} (w Q,($@  
} L8KaK  
.G>~xm0  
t6~~s iQI'  
private void processErrorCode(int nErrorCode) Q!h+1fb  
{  y)3OQ24  
System.err.println("Error Code : " + nErrorCode); b[MKo7  
} B8>@q!G8P  
5oo6d4[  
nQG<OVRClS  
//停止文件下载 yjM!M|  
public void siteStop() ?&POVf>  
{ 22`e7  
bStop = true; e/$M6l$Q*4  
for(int i=0;i<nStartPos.length;i++) ONLhQJCb  
fileSplitterFetch.splitterStop(); YOtzj a]~  
1vCVTuRF  
0SJ(Ln`0K  
} c&"1Z/tR  
} h@Ix9!?+  
//负责部分文件的抓取 jgBJs^JgYG  
**FileSplitterFetch.java wIF)(t-):  
*/ \ (U|&  
package NetFox; hfs QAa  
.GvZv>  
{T3wOi  
import java.io.*; 3(1UI u  
import java.net.*; 4hW:c0  
y.a)M?3  
W2A!BaH%  
public class FileSplitterFetch extends Thread { LWV^'B_X-  
'r} y{`3M  
#y1M1Og  
String sURL; //File URL Jjh=zxR>  
long nStartPos; //File Snippet Start Position $LtCI  
long nEndPos; //File Snippet End Position >n%ckL|rG  
int nThreadID; //Thread's ID Ee=!bv(%70  
boolean bDownOver = false; //Downing is over iGNZC{  
boolean bStop = false; //Stop identical 9<5ii  
FileAccessI fileAccessI = null; //File Access interface h#u k-7  
1(jx.W3  
|2I/r$Q  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @`HW0Y_:  
{ aQV?}  
this.sURL = sURL; 0VIR =Pbp  
this.nStartPos = nStart; vSk1/  
this.nEndPos = nEnd; % xBQX  
nThreadID = id; }1NNXxQ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 f_IsY+@  
} N'?#g`*KW  
K\5/||gi  
ge% tj O  
public void run() -c %'f&P  
{ cZAf?,>u  
while(nStartPos < nEndPos && !bStop) XKvH^Z4h{l  
{ x'V:qv*O  
ePTxuCf>  
>vNE3S_  
try{ 8[oZ>7LMzC  
URL url = new URL(sURL); :PB W=W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m2Wi "X(I_  
httpConnection.setRequestProperty("User-Agent","NetFox"); [\=1|t5n~  
String sProperty = "bytes="+nStartPos+"-"; I%CrsEo  
httpConnection.setRequestProperty("RANGE",sProperty); au/5`  
Utility.log(sProperty); 'Ge8l%p  
SI7r `'7A'  
JY$;m3h  
InputStream input = httpConnection.getInputStream(); yRt7&,}zL  
//logResponseHead(httpConnection); MkM`)g 5  
#X0Y8:vj  
5zH_yZ@+  
byte[] b = new byte[1024]; 3/8<dc  
int nRead; Y5<W"[B!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :%IB34e  
{ ^-(DokdBn  
nStartPos += fileAccessI.write(b,0,nRead); }zrapL"9X  
//if(nThreadID == 1) `|4k>5k  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `Cz_^>]|=  
} KR>o 2  
7~VDk5Z6  
m5cRHo<9Y  
Utility.log("Thread " + nThreadID + " is over!"); n"nfEA3{`  
bDownOver = true; "FLiSz%ME  
//nPos = fileAccessI.write (b,0,nRead); K/8TwB?I  
} 4 Z&KR<2Z  
catch(Exception e){e.printStackTrace ();} seZb;0  
} ^_uCSA'X  
} E*QLw* H  
;+lsNf  
VBK|*Tl  
//打印回应的头信息 yER  
public void logResponseHead(HttpURLConnection con) U=[isi+7  
{ xn1, o MY=  
for(int i=1;;i++) {X-a6OQj  
{ d/\ajQ1::  
String header=con.getHeaderFieldKey(i); !'>,37()  
if(header!=null) +(h{ 3Y|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5e&;f  
Utility.log(header+" : "+con.getHeaderField(header)); %.;;itB  
else =|H.r9-PK6  
break; }w{E<C(M  
} x}#N?d  
} 2g;Id.i>  
i>(TPj|  
/b410NP5  
public void splitterStop() 1+qP7 3a^  
{ uz;eY D  
bStop = true; l6.&<0pLT  
} ?3<Y/Vg%c  
Fp>nu_-"  
LXf|n  
} 40 zO4  
mcxD#+H 3  
)QI#szv6  
/* 7nZ3u _~  
**FileAccess.java Nwk^r75lq  
*//文件访问(定位,写) \Npvm49  
package NetFox; ow#8oUf=  
import java.io.*; ]N:Wt2  
E|W7IgS  
i\=I` Yn+  
public class FileAccessI implements Serializable{ D0h6j0r 5  
C{,Vk/D-0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 T75N0/teS  
RandomAccessFile oSavedFile; 4K,S5^`Gx  
long nPos; m,ur{B8 :  
o 80x@ &A:  
T NF  
public FileAccessI() throws IOException \ZBz]rh*  
{ \xmDkWzE  
this("",0); _AH_<Z(  
} <|hrmwk|  
R0-Y2v  
zO0K*s.yK  
public FileAccessI(String sName,long nPos) throws IOException kkXe=f%  
{ {d> 6*b  
oSavedFile = new RandomAccessFile(sName,"rw"); o Va[  
this.nPos = nPos; bl\;*.s'  
oSavedFile.seek(nPos); t;_1/ mt  
} (*\y  
LdnTdh?  
@@=,bO  
public synchronized int write(byte[] b,int nStart,int nLen) TW=N+ye^1(  
{ {,= hIXo>  
int n = -1; %Lq}5zB  
try{ ypx`!2Q$  
oSavedFile.write(b,nStart,nLen); A>\3FeU>UC  
n = nLen; (R(NEN  
} Bk5ft4v-  
catch(IOException e) i*mI-l  
{ }sp?@C,Z  
e.printStackTrace (); AnpO?+\HF  
} ,_K:DSiB  
Uh'W d_?  
/Z]hX*QR  
return n; Fzz9BEw(i  
} & d* bQv$  
xM/WS':V  
P1<McQ  
} c)c_Qv  
z2q!_ ~  
U@:l~ xJ  
/* <"av /`;  
**SiteInfoBean.java @.pr}S/  
*/ 4I2#L+W  
package NetFox; r>G||/Z  
Zt 1nH  
H7f  Xg  
public class SiteInfoBean { wV,=hMTd&\  
qJw\<7m  
!. :b}t  
private String sSiteURL; //Site's URL ]-l4  
private String sFilePath; //Saved File's Path 2~h Q   
private String sFileName; //Saved File's Name s:I 8~Cc  
private int nSplitter; //Count of Splited Downloading File JC}T*h>Ee  
y8]vl;88yY  
CS0q#?  
public SiteInfoBean() 5'_:>0}  
{//nSplitter的缺省值为5 kqGydGh*"  
//default value of nSplitter is 5 0UQ DB5u  
this("","","",5); m`jGBSlw_  
} l I2UpfkBP  
l>)+HoD  
%m$t'?  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ad4-aWH  
{ |WW'qg]Uu  
sSiteURL= sURL; OOYdrv,  
sFilePath = sPath; Vc+~yh.)  
sFileName = sName; ,,-j5Y  
this.nSplitter = nSpiltter; M->#WGl\B  
f|2QI ~R  
~O 4@b/!4  
} 3w! NTvp  
z'0 =3  
S(:|S(  
public String getSSiteURL() Az/P;C=  
{ k0xm-  
return sSiteURL; <<H'Z  
} 9xL` i-7]  
Htep3Ol3  
1h`#H:  
public void setSSiteURL(String value) fmFs  
{ .L ^F4  
sSiteURL = value; Z*'_/Grv?  
} z0T6a15f!P  
qnO/4\qq  
5'EoB^`8N~  
public String getSFilePath() #:Ukv?  
{ {3 >`k.w  
return sFilePath; ,fj~BkW{  
} T? ,Q=.  
3) XS^WG  
ca%XA|_J  
public void setSFilePath(String value) EDg; s-T=  
{ ,|w,  
sFilePath = value; Wr,pm#gl6  
} Qk&6Z%  
fg GTm:   
)XYCr<s2"  
public String getSFileName() /1r {z1pv\  
{ l Ng)k1  
return sFileName; iF1zLI<A  
} H)K.2Q  
oB+@05m8  
]Y f8  
public void setSFileName(String value) pH0MVu(W  
{ I2?g'tz  
sFileName = value; Dj w#{WR  
} 2F:X:f  
z{qn|#}  
Hlj3z3  
public int getNSplitter() M2nZ,I=l  
{ 'A/ f>W  
return nSplitter; x^ sTGd  
} lsVg'k/Z!  
~%sNPKjA  
] .c$(.  
public void setNSplitter(int nCount) qwo{34  
{ ^0 /!:*?  
nSplitter = nCount; kqLpt  
} 'he&h4fm  
} x!UGLL]_M  
?)4c!3#  
Q>\9/DjUp  
/* /-g%IeF  
**Utility.java ;AT~?o`n  
*/ t s=+k/Z  
package NetFox; K ?V' ?s  
3 FLht L  
2O`s'&.h  
public class Utility { ;zi4W1  
Gdlx0i  
ae] hCWK  
public Utility() J(`(PYo\i  
{ aMyf|l.  
~-NlTx  
d C6t+  
} o [nr)  
qox@_  
//线程睡眠 {-s7_\|p(  
public static void sleep(int nSecond) MG$Df$R  
{ #:nds,   
try{ =UF mN"  
Thread.sleep(nSecond); RaB%N$.9s  
} n^rzl6dy  
catch(Exception e) $p.0[A(N  
{ Fh^Ax3P(  
e.printStackTrace (); q7zHT=@$  
} P L*kjrLu7  
} vrXNa8,L  
d~O)mJ J  
//日志 m[&pR2T  
public static void log(String sMsg) 9 icy&'  
{ :4S~}}N  
System.err.println(sMsg); 5~xv"S(E}  
} 4+a u6ABy  
/Y*6mQ:  
U\;mM\2rE  
public static void log(int sMsg) }I#,o!)Vd  
{  Tv~Ys#  
System.err.println(sMsg); XNB4KjT  
} CGCSfoS9f  
} I)f54AX  
gK- $y9]~+  
YnX6U 1/^  
/* I#](mRJ6  
**TestMethod.java |?<r  
*/ |dk9/xdX  
package NetFox; = k>ygD_  
2(NN QU@Uz  
O`='8'6zW\  
public class TestMethod {  c|~f[  
YN5p@b=FX  
__,}/|K2  
public TestMethod() @m ?&7{y#?  
{ ///xx/weblogic60b2_win.exe O:te;lQ K  
try{ #Pq.^ ^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `Z~\&r=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); JJE0q5[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *qL"&h5W  
fileFetch.start(); w_^g-P[o-  
} Ck^jgB.7  
catch(Exception e){e.printStackTrace ();} e{`DvfY21  
v/}h y$7  
C-L["O0[  
} M9dUo7  
|%7OI#t^  
)\0LxsZ  
public static void main(String[] args) tU(vt0~b  
{ N+0`Jm  
new TestMethod(); <!.Qn Y  
} 5SmgE2}  
} 1N\-Ku  
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