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http断点续传简单实现(java)

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/* rSgOQ  
**SiteFileFetch.java qjm6\ii:)  
*/ V}Ok>6(~  
package NetFox; U/#X,Bi~  
import java.io.*; wsKOafrV  
import java.net.*; qWdob>u  
o?{-K-'B$  
.5^7Jwh  
public class SiteFileFetch extends Thread { i5*BZv>e  
}R9>1u}6  
n8+_Uww  
SiteInfoBean siteInfoBean = null; //文件信息Bean /;X+<Wj  
long[] nStartPos; //开始位置 gLss2i.r  
long[] nEndPos; //结束位置 <"hq}B  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )KdEl9o  
long nFileLength; //文件长度 .)g7s? K  
boolean bFirst = true; //是否第一次取文件 ?3_^SRW&a  
boolean bStop = false; //停止标志 T5_/*`F  
File tmpFile; //文件下载的临时信息 mgd)wZNV  
DataOutputStream output; //输出到文件的输出流 !'z"V_x~  
_'mK=`>u  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) EXbaijHQG  
public SiteFileFetch(SiteInfoBean bean) throws IOException R:5uZAx  
{ 1F' x$~ZI  
siteInfoBean = bean; q/h , jM  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s~NJy'Y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); HhZ>/5'(  
if(tmpFile.exists ()) :|HCUZ*H(T  
{ ==Ah& ){4^  
bFirst = false; <~bvf A=  
read_nPos(); ;%Zu[G`C  
} jmBsPSGIC  
else ,$+ P  
{ &SW~4{n:  
nStartPos = new long[bean.getNSplitter()]; pwg\b  
nEndPos = new long[bean.getNSplitter()]; hnnVp_<]  
} Jm`{MzqL  
oFi_ op  
D~zk2  
X|'[\v2ld  
} iu iVr$E  
.[:y`PCF  
5v[2R.eT-  
public void run() j,79G^/YG  
{ NX&Z=ObHu}  
//获得文件长度  6hO]eS  
//分割文件 WB.w3w [f  
//实例FileSplitterFetch ce<88dL  
//启动FileSplitterFetch线程 7P bwCRg  
//等待子线程返回 TtWWq5X|  
try{ $/kZKoF{f  
if(bFirst) fyF8RTm{  
{ gl~9|$ivj>  
nFileLength = getFileSize(); SUb:0GUa  
if(nFileLength == -1) ,Ma%"cWVC  
{ -KL5sK  
System.err.println("File Length is not known!"); -PCF Om"  
} T0X+\&W  
else if(nFileLength == -2) Oj>;[O"  
{ LlcH#L$  
System.err.println("File is not access!"); >aAsUL5W  
} ' j\~> a3\  
else blKF78  
{ f+%s.[;A  
for(int i=0;i<nStartPos.length;i++) Ys>Z=Eky  
{ w\1K.j=>|N  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); lNo]]a+_  
} gs(ZJO1 /L  
for(int i=0;i<nEndPos.length-1;i++) Aj*|r  
{ GGU>={D)  
nEndPos = nStartPos[i+1]; f_z]kA +H  
} !PfdY&.)  
nEndPos[nEndPos.length-1] = nFileLength; Y;{(?0 s  
} Y?V.O  
} }BWT21'-Y  
#'5{ ?Cb  
629ogJo8  
//启动子线程 (H;,E-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h,ipQ>  
for(int i=0;i<nStartPos.length;i++) 8'Iei78Ov  
{ &&7&/   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M%bD7naBq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?h:xO\h8  
nStartPos,nEndPos,i); mq+x=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {n{-5Y  
fileSplitterFetch.start(); TR9dpt+T  
} -VvN1G6.x?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r8>Qs RnU%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ub]s>aqy   
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v$Xoxp  
nEndPos = " + nFileLength); p^s:s-"f\  
// fileSplitterFetch[nPos.length-1].start(); g'NR\<6A  
l\37/Z  
32p9(HQ  
//等待子线程结束 ,rX|_4 n*  
//int count = 0; ~Kt2g\BSok  
//是否结束while循环 <q`|,mc  
boolean breakWhile = false; GsoD^mjY  
 V*W H  
4t 0p!IxG  
while(!bStop) M9.FtQhK/  
{ ]VaMulb4  
write_nPos(); Uka(Vr:  
Utility.sleep(500); j/F:j5O*  
breakWhile = true; sn8l3h)  
Q>I7.c-M|  
SM4'3d&mf  
for(int i=0;i<nStartPos.length;i++) CQs,G8 \/  
{ p@eW*tE  
if(!fileSplitterFetch.bDownOver) C,B{7s0-  
{ qG3MyK%O\  
breakWhile = false; <l< y R?  
break; C6qGCzlG`  
} i)(-Ad_  
} HfEl TC:3f  
if(breakWhile) +o]J0Gu  
break; (gUVZeVFP  
= O|}R  
Yv3 P]6c.  
//count++; $ve*j=p  
//if(count>4) ft$!u-`  
// siteStop(); >]x%+@{|  
} hX:yn:P~  
aWY#gI{  
k{ulu  
System.err.println("文件下载结束!"); ]f6,4[  
} [*g'Y;W  
catch(Exception e){e.printStackTrace ();} _e "  
} eC@b-q   
xmejoOF  
v?l*jr1-2  
//获得文件长度 GQYB2{e>  
public long getFileSize() w& )ApfL  
{ i^)JxEPr w  
int nFileLength = -1; 4MoxP  
try{ mOJ-M@ME  
URL url = new URL(siteInfoBean.getSSiteURL()); 4!A(7 s4t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 19i=kdH  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4$+/7I \  
_sQhDi  
or(P?Ro  
int responseCode=httpConnection.getResponseCode(); qmtH0I7)  
if(responseCode>=400) Y?%=6S  
{ u17 9!  
processErrorCode(responseCode); ]+Z,HY@;-  
return -2; //-2 represent access is error >6|Xvtf  
} %?J-0  
:Aj[#4-=   
'`&b1Rc  
String sHeader; G@U}4' V9  
91UC>]}H  
$\L=RU!c}  
for(int i=1;;i++) j07b!j:"\}  
{ Ue=1NnRDkA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ->W rBO  
//Utility.log(in.readLine()); L$?YbQo7  
sHeader=httpConnection.getHeaderFieldKey(i); 0y%s\,PsT  
if(sHeader!=null) S~B{G T\M  
{ b@B\2BT  
if(sHeader.equals("Content-Length")) |AS9^w  
{ OpmPw4?}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); OG^#e+  
break; K<v:RbU|[1  
} T+>W(w i  
} [x0*x~1B  
else w}U'>fj  
break; WL;2&S/{@  
} a[J_H$6H!  
} `82^!7!  
catch(IOException e){e.printStackTrace ();} "YN6o_*]  
catch(Exception e){e.printStackTrace ();} LAuaowE\v  
%Lom#:L'  
o`nJJ:Cxq-  
Utility.log(nFileLength); ]3 76F7  
H<   
:` S\p[5  
return nFileLength; foe)_  
} `~1#X  
*LQt=~  
e09QaY  
//保存下载信息(文件指针位置) "sed{?  
private void write_nPos() Bpv"qU7  
{ gH0Rd WX  
try{ [@0Hmd7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); EE*FvI`  
output.writeInt(nStartPos.length); )H{OqZZYD  
for(int i=0;i<nStartPos.length;i++) ;pG5zRe  
{ *s?C\)x  
// output.writeLong(nPos); yS4nB04`=  
output.writeLong(fileSplitterFetch.nStartPos); `m\ ?gsw7  
output.writeLong(fileSplitterFetch.nEndPos); %V92q0XW  
} x) R4_ 3  
output.close(); 2,p= %  
} IeB^BD+j  
catch(IOException e){e.printStackTrace ();} `eKFs0M.  
catch(Exception e){e.printStackTrace ();} 33NzQb  
} n M `pnR_  
uk3PoB^>  
q5.5%W  
//读取保存的下载信息(文件指针位置) ^geY Ay  
private void read_nPos() 5Z[HlN|-!  
{ $S U<KNMZ  
try{ 64SRW8AH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); zS `>65}e  
int nCount = input.readInt(); >(W\Eh{J  
nStartPos = new long[nCount]; *7C l1o  
nEndPos = new long[nCount]; bK|nxL  
for(int i=0;i<nStartPos.length;i++) ;JX2ebx  
{ P?zL`czWd  
nStartPos = input.readLong(); hYVy65Ea  
nEndPos = input.readLong(); >| hqt8lY  
} Agwl2AM5k  
input.close(); Rc}#4pM8  
} 3# idXc  
catch(IOException e){e.printStackTrace ();} G$jw#a[L  
catch(Exception e){e.printStackTrace ();} gh% Q9Ni-  
} T8Ye+eP}  
@Z89cTO  
o3.b='HAm  
private void processErrorCode(int nErrorCode) BUXlHh%<R  
{ Xliw(B'\a4  
System.err.println("Error Code : " + nErrorCode); 2`V(w[zTr  
} 1Ch0O__2L  
6t4{aa!L|9  
aK8X,1g%)  
//停止文件下载 I}\`l+  
public void siteStop() lht :%Ts$  
{ `91?^T;\F  
bStop = true; l(~NpT{=V  
for(int i=0;i<nStartPos.length;i++) C{YTHN n  
fileSplitterFetch.splitterStop(); :(i=> ~O  
XZxzw*Y1J  
cB2~W%H  
} ^F-AZP /5F  
} Pa/2])w  
//负责部分文件的抓取 Zrq\:KxX  
**FileSplitterFetch.java nDXy$f8  
*/ Suk;##I  
package NetFox; |q 0iX2W  
a'7RzN ,]  
rM20Y(|  
import java.io.*; h[gKyxZ/t  
import java.net.*; / 16 r_l  
9iGp0_J  
)>!y7/3  
public class FileSplitterFetch extends Thread { yXro6u?rC  
r?WOum  
8VMD304  
String sURL; //File URL e_llW(*l8^  
long nStartPos; //File Snippet Start Position #G("Oh  
long nEndPos; //File Snippet End Position $3(E0\#O  
int nThreadID; //Thread's ID y9 K'(/  
boolean bDownOver = false; //Downing is over /+f3jy:d  
boolean bStop = false; //Stop identical .;37 e  
FileAccessI fileAccessI = null; //File Access interface 3_Mynop  
\5F {MBx !  
U.J/ "}5`T  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8[u$CTl7a  
{ SOvo%L@  
this.sURL = sURL; UeaHH]U  
this.nStartPos = nStart; _%<q ZT  
this.nEndPos = nEnd; j8?rMD~  
nThreadID = id; Ki%RSW(_`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 OZno 3Hn  
} Edl .R}&1  
zC!Pb{IaH  
\C`2z]V%  
public void run() t,qz%J&a  
{ CPu~^ik  
while(nStartPos < nEndPos && !bStop) `YK#m4gc  
{ 0|~3\e/QV  
Oyy E0  
?I 7hbqQd  
try{ fUB+9G(Bx  
URL url = new URL(sURL); Kk/cI6`W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \`YV)"y" ~  
httpConnection.setRequestProperty("User-Agent","NetFox"); fCi1JH;  
String sProperty = "bytes="+nStartPos+"-"; 0vcFX)]yW  
httpConnection.setRequestProperty("RANGE",sProperty); Wp//SV  
Utility.log(sProperty); \PK}4<x}  
U_5\ FM  
E1>zKENN;  
InputStream input = httpConnection.getInputStream(); &=l aZxe  
//logResponseHead(httpConnection); UvVq#<-  
f/g-b]0  
'];=1loD  
byte[] b = new byte[1024]; Q}]RB$ZS  
int nRead; kSO:xS0 _N  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?^ `EI}g  
{ Med0O~T%  
nStartPos += fileAccessI.write(b,0,nRead); ?yAjxoE~?  
//if(nThreadID == 1) yo#fJ`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {_X&{dZLX  
} D<xDj#Z~1  
G":u::hR  
d7v_>  
Utility.log("Thread " + nThreadID + " is over!"); \Gy+y`   
bDownOver = true; 8#15*'Y  
//nPos = fileAccessI.write (b,0,nRead); VY "i>Ae  
} 79>_aD9  
catch(Exception e){e.printStackTrace ();} CM+/.y T  
} W.  p'T}2  
} tCr? !Y~  
jUy$aGX  
]f3R;d  
//打印回应的头信息 KJ8Qi+cZ  
public void logResponseHead(HttpURLConnection con) r<-@.$lf  
{ :tBZu%N/N  
for(int i=1;;i++) d ]Mjr2h  
{ _~uYNvmg  
String header=con.getHeaderFieldKey(i); oCuKmK8  
if(header!=null) G1/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); aT PmW]w6  
Utility.log(header+" : "+con.getHeaderField(header)); }G 1hB#j  
else XN~r d,MZ%  
break; 5w@Q %'o`I  
} 1fU~&?&-u  
} };]f 3  
4GqE%n+ta~  
W> rx:O+  
public void splitterStop() }B2qtb3  
{ |BA<> WE  
bStop = true; >y iE}  
} kB ;!EuL  
of?0 y-LT%  
X1Y+ao1)  
} $Z4IPs  
W&Kjh|[1QZ  
1TL~I-G&n  
/* N1u2=puJY  
**FileAccess.java 3(>NS?lX  
*//文件访问(定位,写) 'A9U[|  
package NetFox; y7Y g$)sL  
import java.io.*; '@eH)wh@m)  
3dC ;B@  
kIYV%O   
public class FileAccessI implements Serializable{ &p:GB_  
nAW`G'V#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]LZ,>v  
RandomAccessFile oSavedFile; I xE }v%&  
long nPos; iU a `<  
Ems0"e  
2~2j?\AEd.  
public FileAccessI() throws IOException FK.Qj P:  
{ *p7_rY  
this("",0); \x+"1  
} ajALca4  
{AMoE +U  
M]M(E) *5  
public FileAccessI(String sName,long nPos) throws IOException wT-@v,$  
{ rgXD>yu(  
oSavedFile = new RandomAccessFile(sName,"rw"); ^Ts8nOGMh  
this.nPos = nPos; J9yB'yE8  
oSavedFile.seek(nPos); ?u_O(eg  
} #Vh$u%q3  
~F=,)GE  
odC}RdN  
public synchronized int write(byte[] b,int nStart,int nLen) +a((,wAN2  
{ #gY|T|  
int n = -1;  0@dN$e  
try{ 6i_dL|c  
oSavedFile.write(b,nStart,nLen); ;B@-RfP  
n = nLen; T&~7*j(|e  
} xl;0&/7e  
catch(IOException e) c %.vI  
{ \h 1T/_4  
e.printStackTrace (); MyJG2C#R  
} 6pY<,7t0  
Y'v;!11#  
y]TNjLpo$  
return n; 7H5t!yk|9  
} <.B^\X$  
Ug,23  
zV"oB9\9O  
} j9/Ev]im|F  
B[nkE+s  
om}jQJ]KH  
/* N(BCe\FV  
**SiteInfoBean.java `<^1Ik[g  
*/ 3WQ"3^G  
package NetFox; 2rJeON  
bjYaJtn  
Vm <9/UG<  
public class SiteInfoBean { uw`fC%-xh  
26<Wg7/,  
W;@9x1jK X  
private String sSiteURL; //Site's URL ,=Fn6'  
private String sFilePath; //Saved File's Path ?sm@lDZ\  
private String sFileName; //Saved File's Name S2*ER  
private int nSplitter; //Count of Splited Downloading File auT'ATW7i  
|=W=H6h*  
s;4r)9Uvx  
public SiteInfoBean() VPqMbr"L[  
{//nSplitter的缺省值为5 zS+_6s  
//default value of nSplitter is 5 R x.]m0  
this("","","",5); {f<\`  
} K JX@?1"  
J,=: ] t  
bD;c>5t  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) OlF5~VAbfb  
{ K?:wX(JYT  
sSiteURL= sURL; F_&bE@k  
sFilePath = sPath; 0[T>UEI?  
sFileName = sName; v5N2$Sqp*  
this.nSplitter = nSpiltter; jwd{CN%  
&9F(uk=X  
T^~9'KDd  
} {IpIQ-@l  
e=%6\&q  
`[zd  
public String getSSiteURL() ]~A<Q{  
{ ?Ok@1  
return sSiteURL; 2?bE2^6  
} +|=5zWI /  
7yK1Q_XY>  
wu2C!gyBo  
public void setSSiteURL(String value) `Ufv,_n  
{ Vdz(\-}ao  
sSiteURL = value; #RA3 T[A  
} qTl/bFD  
U\\nSU  
?dcR!-3  
public String getSFilePath() q"Z!}^{  
{ U DC>iHt  
return sFilePath; mC}!;`$8p  
} >7^+ag~&  
r!7e:p JLO  
/NDuAjp[@  
public void setSFilePath(String value) [Ifhh2  
{ 8xEOR!\!`k  
sFilePath = value; ;y{VdT  
} :9Vd=M6,  
6b8@6;&LI  
0piBK=tE/  
public String getSFileName() X) TUKt  
{ KZxA\,Y'5  
return sFileName; _,i+gI[  
} yw( E}   
k v}<u  
KtFxG6a  
public void setSFileName(String value)  !&Z,ev  
{ U5z}i^8a  
sFileName = value; {)vue0 vP  
} Q$(0Nx<  
n*oa J<o%  
A' \jaB  
public int getNSplitter() <XHS@|  
{ "n3i (sZ  
return nSplitter; ;5.o;|w?!  
} aumXidb S  
;|Z;YK@20  
Q&9%XF uM  
public void setNSplitter(int nCount) >Lo!8Hen  
{ dWI.t1`i  
nSplitter = nCount; OZ$"P<X_"  
} ]%y~cq  
} D-8>?`n\  
BI\+ NGrB  
5w#*JK   
/* '%m0@5|hCD  
**Utility.java 7(<49bb.V  
*/ =!#iC?I  
package NetFox; 4#qjRmt  
,ZYj8^gF  
#89h}mp'  
public class Utility { Bn"r;pqWiT  
[wM<J$=2  
m7XJe[O  
public Utility() a#0G mK  
{ /Jc?;@{  
|m%M$^sZ}  
QS~;C&1Hl  
} ')9%eBaeK  
@x@w<e%  
//线程睡眠 ItTIU  
public static void sleep(int nSecond) J L9d&7-  
{ lbES9o5  
try{ O^ ]I>A#d  
Thread.sleep(nSecond); 8dw]i1t<  
} TgaDzF,j{A  
catch(Exception e) / -=(51}E  
{ jz[|rwAp  
e.printStackTrace (); lK^Q#td:`  
} (jD..qMs#  
} a.5s5g)8  
T2wn!N?r  
//日志  afEp4(X~  
public static void log(String sMsg) W7a s =+;X  
{ -?b@6U  
System.err.println(sMsg); >EMgP1  
} 1q!JpC^  
f=}Mr8W'  
eh'mSf^=p  
public static void log(int sMsg) /S;o2\  
{ DJE/u qE  
System.err.println(sMsg); wS2iyrIB  
} >:]fN61#  
} xQ7n$.?y@  
,h2q 37  
We]X+>BlO  
/* ~MY (6P  
**TestMethod.java B-[SUmHr  
*/ ;f-|rC_"  
package NetFox;  W4CI=94  
$/C<^}A  
71tMX[x  
public class TestMethod { ]tZ5XS  
h6x+.}}  
81_3{OrE<  
public TestMethod() D,eJR(5I  
{ ///xx/weblogic60b2_win.exe Snt=Hil`  
try{ H/V%D O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); uz4mHyS6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .Qh8I+Q%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); dITnPb)i  
fileFetch.start(); G 7)D+],{Y  
} v%< _Mh  
catch(Exception e){e.printStackTrace ();} fC3IxlG  
s/[i>`g/9  
0iX qAa  
} =X X_C nn  
V8Q#%#)FHe  
Kc udWW]  
public static void main(String[] args) 8{+~3@T  
{ @sKAsn  
new TestMethod(); 16N8h]l  
} `Ik}Xw  
} 73~Mq7~8  
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