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http断点续传简单实现(java)

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/* lO $M6l  
**SiteFileFetch.java xN"KSQpu  
*/ <vt^=QA'  
package NetFox; G^mk<pH  
import java.io.*; 'v|2} T*  
import java.net.*; $fKwJFr  
P'9aZd  
o m_&|9B)  
public class SiteFileFetch extends Thread { 4_.k Q"'DH  
J|FyY)_  
&< Gq-IN  
SiteInfoBean siteInfoBean = null; //文件信息Bean T %a]3  
long[] nStartPos; //开始位置 j|G-9E  
long[] nEndPos; //结束位置 oZCi_g 5i  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a3c4#'c|D  
long nFileLength; //文件长度 nnGA_7-t  
boolean bFirst = true; //是否第一次取文件 g[M@  
boolean bStop = false; //停止标志 T4!]^_t^  
File tmpFile; //文件下载的临时信息 NuO>zAu  
DataOutputStream output; //输出到文件的输出流 qfYb\b  
Ee|+uQ981>  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) H+5]3>O-$  
public SiteFileFetch(SiteInfoBean bean) throws IOException aY:(0en]&  
{ k13/yiv  
siteInfoBean = bean; +~fu-%,k  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); M.8!BB7\8e  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); w|nVK9.  
if(tmpFile.exists ()) EhFhL4Xdn  
{ l.)N  
bFirst = false; Ba+OoS  
read_nPos(); iz^wBQ  
} R-Fi`#PG2  
else *>'R R<  
{ ABHZ)OM  
nStartPos = new long[bean.getNSplitter()]; Lv^j l  
nEndPos = new long[bean.getNSplitter()]; x b0+4w|  
} }\0"gM  
*i?qOv /=>  
?*s!&-KI  
_@OYC<  
} yX~[yH+Pn  
m~U{ V9;*  
F>b6fUtR  
public void run() (&*F`\  
{ '9/kDkt!  
//获得文件长度 ^n2w6U0  
//分割文件 R$@.{d&:w  
//实例FileSplitterFetch .4Ny4CMHZ  
//启动FileSplitterFetch线程 o7T|w~F~R  
//等待子线程返回 1 I+5  
try{ :> q?s  
if(bFirst) g^C6"rsnl  
{ (KQt%]  
nFileLength = getFileSize(); OXacI~C  
if(nFileLength == -1) *(scSC>  
{ r#Fu<so,  
System.err.println("File Length is not known!"); qJ/C*Wqic  
} 8Cqs@<r4Od  
else if(nFileLength == -2) "|G,P-5G"  
{ ^]DWrmy  
System.err.println("File is not access!"); @Hf }PBb  
} k`AJ$\=  
else >gSerDH8\  
{ ~+np7  
for(int i=0;i<nStartPos.length;i++) ". 0W8=  
{ H\k5B_3OU  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 72,iRH  
} y%,BDyK  
for(int i=0;i<nEndPos.length-1;i++) :9YQX(l8  
{ -0X> y  
nEndPos = nStartPos[i+1]; )mPlB.  
} 1}uDgz^  
nEndPos[nEndPos.length-1] = nFileLength; z )pV$  
} I7~|!d6  
} =z3jFaZ  
9A_7:V]_  
/)I9+s#q9o  
//启动子线程 vvM)Rb,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6-=_i)kzq  
for(int i=0;i<nStartPos.length;i++) }gW}Vr <  
{ 7asq]Y}<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), XJzXxhk2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ".)_kt[  
nStartPos,nEndPos,i); O$H150,Q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H+;wnI>@  
fileSplitterFetch.start(); YzZF^q^I  
} WNb$2q=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RrHnDO'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); EDo@J2A  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @(cS8%wK  
nEndPos = " + nFileLength); xB(:d'1|  
// fileSplitterFetch[nPos.length-1].start(); x]ti3?w  
6b/b} vl  
':V_V. :  
//等待子线程结束 ]1&9~TL  
//int count = 0; ~{+{pcO}  
//是否结束while循环 h2%:;phH  
boolean breakWhile = false; >.iw8#l  
/=@vG Vp6  
%&Cl@6  
while(!bStop) _o.Z`]  
{ 4iz&"~&1  
write_nPos(); ]K7  64}  
Utility.sleep(500);  /Xz4q!Ul  
breakWhile = true; +*J4q5;E[?  
dNQSbp  
vy@Lu cB  
for(int i=0;i<nStartPos.length;i++) pD#"8h  
{ doc  
if(!fileSplitterFetch.bDownOver) aHC;p=RQ\A  
{ ?X'* p<`  
breakWhile = false; ?i~/gjp  
break; (@ E#O$'  
} "Cc"y* P  
} S7a6ntei  
if(breakWhile) C):d9OI?  
break; zb/Xfu.)?6  
@WHd(ka!  
@S7=6RKa[  
//count++; H040-Q;S'  
//if(count>4) =BS'oBn^6  
// siteStop(); XQOprIJ U  
} F?} *ovy  
udGGDH  
f hG2  
System.err.println("文件下载结束!"); }qv-lO  
} XyphQ}\u  
catch(Exception e){e.printStackTrace ();} C[nr>   
} ? SP7vQ/  
-^H5z+"^  
~{YgM/c|dt  
//获得文件长度 :WIf$P?X  
public long getFileSize() WWcm(q =  
{ Noxz kpMF  
int nFileLength = -1; ?0NSjK5ma  
try{ Ro]IE|Fv  
URL url = new URL(siteInfoBean.getSSiteURL()); 9'q/&uH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <88}+j  
httpConnection.setRequestProperty("User-Agent","NetFox"); hZWK5KwT  
|u;BAb  
/ JeqoM"x  
int responseCode=httpConnection.getResponseCode();  hu(K!>{  
if(responseCode>=400) `_U0>Bfg;  
{ FRt/{(jro  
processErrorCode(responseCode); Zk#i9[g9*  
return -2; //-2 represent access is error m]d6@"Z.  
} ^Cn]+0G#C8  
Kw0V4UF  
0~b6wuFl  
String sHeader; e K1m(E.=  
pE/3-0;}N  
MD4 j~q\ g  
for(int i=1;;i++) 1IQOl  
{ +Z&&H'xD  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); z %3"d0  
//Utility.log(in.readLine()); Jf<yTAm  
sHeader=httpConnection.getHeaderFieldKey(i); q>(u>z!  
if(sHeader!=null) 7Y|>xx=v  
{ $a*Q).^  
if(sHeader.equals("Content-Length")) c9TAV,/fF*  
{ bNjaCK<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); fC GDL6E  
break; ?VZXJO{^  
} qb> r\bc  
} T 0v@mXBQ  
else $;i$k2n:  
break; 60%~+oHi~  
} T:%wX9W  
} PnIvk]"Ab  
catch(IOException e){e.printStackTrace ();} FP9<E93br  
catch(Exception e){e.printStackTrace ();} g~hk-nXL.  
d<GG (  
q\t>D _lU  
Utility.log(nFileLength); *DC Nu{6  
FR,#s^kF  
sx<+ *Trl  
return nFileLength; <<On*#80w  
} 0S:!Gv +  
|z|)r"*\4  
\v3> Eo[  
//保存下载信息(文件指针位置) |@L &yg,x  
private void write_nPos() *_/eAi/WG  
{ G'?f!fz;  
try{ 7cmr *y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5f&{!N  
output.writeInt(nStartPos.length); , HI%Xn  
for(int i=0;i<nStartPos.length;i++) VWA-?%r  
{ [^d6cMEOlc  
// output.writeLong(nPos); ok%a|Zz+]  
output.writeLong(fileSplitterFetch.nStartPos); z?uQlm*We  
output.writeLong(fileSplitterFetch.nEndPos); aRO_,n9  
} -~O;tJF2  
output.close(); 9g&)6,<  
} tct 5*.|  
catch(IOException e){e.printStackTrace ();} =PKt09b^  
catch(Exception e){e.printStackTrace ();} ssX6kgq_(  
} @)Hbgkdi  
E}b> 7L&w  
W3{<e"  
//读取保存的下载信息(文件指针位置) YNgR1 :l  
private void read_nPos() 9CK\tx&  
{ OwiWnS<  
try{ gvc' $9%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @@{_[ir  
int nCount = input.readInt(); ^,Y~M_=  
nStartPos = new long[nCount]; ^W[B[Y<k  
nEndPos = new long[nCount]; ghobu}wuF  
for(int i=0;i<nStartPos.length;i++) |6(qg5"  
{ llaZP(pJ  
nStartPos = input.readLong(); Av v  
nEndPos = input.readLong(); =Mu'+,dT  
} ~0[G/A$]  
input.close(); 4&]To@>  
} )>/j&>%  
catch(IOException e){e.printStackTrace ();} ^tg6JB;s  
catch(Exception e){e.printStackTrace ();} !: EW21m  
} Qk~0a?#y5  
]IHD:!Z-=  
+NLQYuN  
private void processErrorCode(int nErrorCode) fJn3"D'  
{ 7\0|`{|R@  
System.err.println("Error Code : " + nErrorCode); \p3nd!OIG  
} PD}SPOA`U3  
+1+A3  
=2g[tsY  
//停止文件下载 =Qj+Ug'  
public void siteStop() Qor{1_h)+9  
{ Yn$>QS 4  
bStop = true; SD|4ybK>d  
for(int i=0;i<nStartPos.length;i++) 8!&ds~?  
fileSplitterFetch.splitterStop(); =Y]'5cn{  
,Og[[0g  
VO @ 4A6  
} 3<jAp#bE  
} 1fO2)$Y  
//负责部分文件的抓取 fUp|3bBE  
**FileSplitterFetch.java }/7.+yD  
*/ q1H~ |1  
package NetFox; e"*BHvy F  
]Qd{ '}+  
dl:-k  r8  
import java.io.*; UIQQ \,3  
import java.net.*; ~ W@X-  
:]yg  
p7s@%scp  
public class FileSplitterFetch extends Thread { tzPC/?  
h(_P9E[g  
\WcB9  
String sURL; //File URL [ne" T  
long nStartPos; //File Snippet Start Position 4b]_ #7Qm  
long nEndPos; //File Snippet End Position Yhe+u\vGs\  
int nThreadID; //Thread's ID "2%>M  
boolean bDownOver = false; //Downing is over sA3UeTf  
boolean bStop = false; //Stop identical k'g$2  
FileAccessI fileAccessI = null; //File Access interface p<q].^M  
c& 3#-DNI  
<8f(eP\*F  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException u %'y_C3  
{  U7E  
this.sURL = sURL; o_sQQF  
this.nStartPos = nStart; .?B{GnB>  
this.nEndPos = nEnd; l^ARW E  
nThreadID = id; wEE2a56L-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6p#g0t  
} EA6t36|TX  
+GYS26  
]Dh1~k.Kp  
public void run() 8-ZUS|7B  
{ <.}Ua(  
while(nStartPos < nEndPos && !bStop) wDMjk2 YN  
{ Ssw&'B|o  
#\LZ;&T'N  
Nl { 7  
try{ U~wjR"='  
URL url = new URL(sURL); JIMWMk;ot  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o*-9J2V=J  
httpConnection.setRequestProperty("User-Agent","NetFox"); C-Ig_Nc  
String sProperty = "bytes="+nStartPos+"-";   La9r  
httpConnection.setRequestProperty("RANGE",sProperty); eHUg-\dy  
Utility.log(sProperty); G,=F<TnI'  
Hng!'  
#MglHQO+  
InputStream input = httpConnection.getInputStream(); U-eI\Lu  
//logResponseHead(httpConnection); 3?@?-q2g  
0Qp[\ia  
Fom>'g*  
byte[] b = new byte[1024]; Z["BgEJ  
int nRead; I(n }<)eF  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p-,Iio+  
{ S.W^7Ap  
nStartPos += fileAccessI.write(b,0,nRead); mL$f[  
//if(nThreadID == 1) v77fQ0w3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S7CV w,2  
} ' l|R5   
+bUW!$G  
ljVIE/iq  
Utility.log("Thread " + nThreadID + " is over!"); =e{.yggE  
bDownOver = true; nkRK +~>  
//nPos = fileAccessI.write (b,0,nRead); E?cZ bn*>`  
} L<=)@7  
catch(Exception e){e.printStackTrace ();} (UGol[f<  
} 'B`#:tX^N  
} c" +zgP  
#]y5z i  
Tm_8<$ 7  
//打印回应的头信息 =JW[pRI5a  
public void logResponseHead(HttpURLConnection con) f?^S bp  
{ f`?0WJ(M  
for(int i=1;;i++) #uKWuGz]  
{ H2U:@.o2&  
String header=con.getHeaderFieldKey(i); M&f#wQ  
if(header!=null) RLHYw@-j@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ybE[B}pOeZ  
Utility.log(header+" : "+con.getHeaderField(header)); W$'0Dc  
else 8+>\3j  
break; Bc<n2 C0  
} TF\sP8>V  
} 5kn+ >{jh`  
|1Hc&  
0% +'  
public void splitterStop() 8_a3'o%5  
{ !y. $J<  
bStop = true; \ I:.<2i  
} {cR=N~_EO  
+c) TDH  
C ) ?uE'  
} Kt6>L5:94  
c`jDW S  
PS@*qTin  
/* Ri @`a  
**FileAccess.java 1 i3k  
*//文件访问(定位,写) NR3`M?Hjf  
package NetFox; =9$mbn r  
import java.io.*; 'zxoRc-b@N  
"Pj}E=!k  
J +q|$K6  
public class FileAccessI implements Serializable{ YeyGN  
mmP U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 L/i(KF{  
RandomAccessFile oSavedFile; ARWZ; GX  
long nPos;  D:JS)+]  
9i%9   
wf9z"B  
public FileAccessI() throws IOException +EkW>$  
{ ?WHy0x20  
this("",0); _a5(s2wq+  
} `R+,1"5=  
e&1 \'Zq?>  
Mu2`ODe]  
public FileAccessI(String sName,long nPos) throws IOException OCK>%o$[  
{ pM2a(\K,k^  
oSavedFile = new RandomAccessFile(sName,"rw"); m@\ZHbq  
this.nPos = nPos; re`t ]gzb  
oSavedFile.seek(nPos); <3Gqv9Y&  
} :=fvZAWD  
iM5vrz`n  
9Cvn6{  
public synchronized int write(byte[] b,int nStart,int nLen) ;LMWNy4  
{ c1%rV`)]  
int n = -1; _|zBUrN  
try{ 62\&RRB i  
oSavedFile.write(b,nStart,nLen); XYfv(y  
n = nLen; KDTDJ8  
} q3S+Y9L  
catch(IOException e) ST;t, D:  
{ &&7r+.Y  
e.printStackTrace (); Oy_c  
} f*fE};  
&HDP!SLS  
[BDGR B7d"  
return n; &tE.6^F  
} /k6fLn2;  
6+` tn  
Yc;ec9~  
} n7l%gA*  
RiR:69xwR*  
e;ty!)]  
/* >EP(~G3u  
**SiteInfoBean.java 4["&O=:d  
*/ s| -FH X  
package NetFox; ( u`W!{1\  
HOZRYIQB  
! '0S0a8  
public class SiteInfoBean { 8)wt$b  
s9j7Psd  
PDP[5q r  
private String sSiteURL; //Site's URL "A[ b rG  
private String sFilePath; //Saved File's Path |d}MxS`^  
private String sFileName; //Saved File's Name UtJa3ya  
private int nSplitter; //Count of Splited Downloading File `78V%\  
.C bGDZ  
1-VT}J(  
public SiteInfoBean() NlF}{   
{//nSplitter的缺省值为5 'q{733o  
//default value of nSplitter is 5 Vrp[r *V@E  
this("","","",5); 'C>U=cE7  
} ]R IVc3?;$  
xf,5R9g/  
W?XizTW  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1*Ar{:+ua  
{ `G$1n#&  
sSiteURL= sURL; .}`hCt08  
sFilePath = sPath; ig_2={Q@  
sFileName = sName; :i*JnlvZ  
this.nSplitter = nSpiltter; )=^w3y  
`<fh+*  
9uYyfb: ,z  
} HeA{3s  
OB^Tq~i  
\a|L/9%  
public String getSSiteURL() ~<9{#uM  
{ RBGX_v?  
return sSiteURL; v:|( 8Y  
} )qU7`0'8  
(@sp/:`6  
R,_d1^|*w  
public void setSSiteURL(String value) >e&:`2%.  
{ -?a<qa?$  
sSiteURL = value; GWP dv  
} p>*i$  
P?ep]  
Re= WfG  
public String getSFilePath() q4 k@l  
{ P0GeZ02]  
return sFilePath; ,FQK;BU!lh  
} NAr1[{^E,  
d&(_|xq#  
n$)_9:Z-j  
public void setSFilePath(String value) Mz=!w]qDH  
{ HOi C  
sFilePath = value; A74920X`W  
} ,|T7hTn=  
-yx/7B5@  
nU z7|y  
public String getSFileName() NgZUnh3{  
{ !<\Br  
return sFileName; v"Jgw;3  
} 5OP`c<  
}_OM$nzj  
fI|[Z+"  
public void setSFileName(String value) x"4%(xBu  
{ d/,E2i{I7  
sFileName = value; 8cxai8  
} NAFsFngqH  
8cWZ"v  
k|E]YvnfG  
public int getNSplitter() @gfDp<  
{ RW7(r/C  
return nSplitter; 7C,T&g 1:  
} IB5BO7J  
;N=G=X|}  
n!ok?=(kQ  
public void setNSplitter(int nCount) !K0JV|-?t  
{ cma*Dc  
nSplitter = nCount; -$a>f4]  
} 0@=MOGQb  
} H AB#pd9  
$#NQ <3  
sd0r'jb  
/* 6[dur'x  
**Utility.java @,H9zrjVFZ  
*/ u5E]t9~Pq  
package NetFox; Rm>^tu -  
j|(Z#3J  
&Ral+J  
public class Utility { w!3>N"em  
/2uQCw&x-  
+Ov2`O8?  
public Utility() pa]"iZz  
{ ~oD8Rnf  
m:CTPzAt  
y=sGe!^  
} 9s$U%F6}  
& eZfQ27$  
//线程睡眠 1cJsj  
public static void sleep(int nSecond) o|8`>!hF  
{ t}p@:'  
try{ HK=[U9 o?  
Thread.sleep(nSecond); NX6nQ  
} x5si70BKC/  
catch(Exception e) tbDoP Y  
{ E+xuWdp.*  
e.printStackTrace (); pw020}`  
} i^"+5Eq[D  
} U9d:@9Y  
}ZOFYu0f  
//日志 @ GDX7TPV  
public static void log(String sMsg) QB{rVI>mI!  
{ }xb=<  
System.err.println(sMsg); d5j_6X  
} h#}YKWL  
arZ@3]X%a  
,TC;{ $O5  
public static void log(int sMsg) x8#ODuH  
{ SAv<&  
System.err.println(sMsg); +Ezgn/bS&  
} =P77"Dd  
} TYgQJW?  
j ) vlM+  
u:gtOjk2  
/* e]>ori 8  
**TestMethod.java h5zVGr  
*/ t!;/Z6\Pb  
package NetFox; y }2F9=  
 -7]Xjb5  
)9nElb2  
public class TestMethod { YE+$H%Jl!  
# '|'r+  
9ptFG]lZ  
public TestMethod() L;t)c  
{ ///xx/weblogic60b2_win.exe sKaE-sbJY  
try{ #VbVs l  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); T3&`<%,f  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /\d$/~BFi  
SiteFileFetch fileFetch = new SiteFileFetch(bean); UHO_Z  
fileFetch.start(); ] gb=  
} xyHejE}  
catch(Exception e){e.printStackTrace ();} ;&;W T  
T~8  .9g  
t2{~bzq1X  
} /uqu32;o  
i, nD5 @#  
]rBM5~  
public static void main(String[] args) VDEv>u4  
{ } /^C|iS7  
new TestMethod();  q" @  
} `cB_.&  
} 748CD{KxW  
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