JDBC reads database metadata and generates Java entity classes

JDBC reads database metadata and generates a Java entity class <br/> package COM. nffish. util; </P> <p> Import Java. io. filewriter; <br/> Import Java. io. ioexception; <br/> Import Java. io. printwriter; <br/> Import Java. SQL. connection; <br/> Import Java. SQL. preparedstatement; <br/> Import Java. SQL. resultsetmetadata; <br/> Import Java. SQL. sqlexception; </P> <p> Import COM. nffish. common. dbsession; </P> <p> public class genentitytool {<br/> private string tablename = "petdiary"; </P> <p> private string [] colnames; // array of column names </P> <p> private string [] coltypes; // array of column name types </P> <p> private int [] colsizes; // array of column name size </P> <p> private Boolean f_util = false; // whether to import the Java package. util. * </P> <p> private Boolean f_ SQL = false; // whether to import the Java package. SQL. * </P> <p> Public genentitytool () {<br/> connection conn = dbsession. getconnection (); // obtain the database connection <br/> string strsql = "select * from" + tablename; <br/> try {<br/> preparedstatement pstmt = Conn. preparestatement (strsql); <br/> resultsetmetadata rsmd = pstmt. getmetadata (); <br/> int size = rsmd. getcolumncount (); // total number of columns <br/> colnames = new string [size]; <br/> coltypes = new string [size]; <br/> colsizes = new int [size]; <br/> for (INT I = 0; I <rsmd. getcolumncount (); I ++) {<br/> colnames [I] = rsmd. getcolumnname (I + 1); <br/> coltypes [I] = rsmd. getcolumntypename (I + 1); <br/> If (coltypes [I]. equalsignorecase ("datetime") {<br/> f_util = true; <br/>}< br/> If (coltypes [I]. equalsignorecase ("image") <br/> | coltypes [I]. repeated signorecase ("text") {<br/> f_ SQL = true; <br/>}< br/> colsizes [I] = rsmd. getcolumndisplaysize (I + 1); <br/>}< br/> string content = parse (colnames, coltypes, colsizes ); <br/> try {<br/> filewriter fw = new filewriter (initcap (tablename) + ". java "); <br/> printwriter PW = new printwriter (FW); <br/> PW. println (content); <br/> PW. flush (); <br/> PW. close (); <br/>}catch (ioexception e) {<br/> E. printstacktrace (); <br/>}< br/>} catch (sqlexception e) {<br/> E. printstacktrace (); <br/>}finally {<br/> dbsession. closeconnection (conn); <br/>}</P> <p>/** <br/> * parse (generate entity-class subject code) <br/> */<br/> private string parse (string [] colnames, string [] coltypes, int [] colsizes) {<br/> stringbuffer sb = new stringbuffer (); <br/> If (f_util) {<br/> Sb. append ("Import Java. util. date;/R/N "); <br/>}< br/> If (f_ SQL) {<br/> Sb. append ("Import Java. SQL. *;/R/n/R/N "); <br/>}< br/> Sb. append ("public class" + initcap (tablename) + "{/R/N"); <br/> processallattrs (SB); <br/> processallmethod (SB ); <br/> Sb. append ("}/R/N"); <br/> system. out. println (sb. tostring (); <br/> return sb. tostring (); </P> <p >}</P> <p>/** <br/> * generate all methods <br/> * @ Param sb <br/> */<br/> private void processallmethod (stringbuffer SB) {<br/> for (INT I = 0; I <colnames. length; I ++) {<br/> Sb. append ("/tpublic void set" + initcap (colnames [I]) + "(" <br/> + sqltype2javatype (coltypes [I]) + "" + colnames [I] <br/> + ") {/R/N"); <br/> Sb. append ("/T/tThis. "+ colnames [I] +" = "+ colnames [I] +";/R/N "); <br/> Sb. append ("/t}/R/N"); </P> <p> Sb. append ("/tpublic" + sqltype2javatype (coltypes [I]) + "get" <br/> + initcap (colnames [I]) + "() {/R/N "); <br/> Sb. append ("/T/treturn" + colnames [I] + ";/R/N"); <br/> Sb. append ("/t}/R/N "); <br/>}</P> <p>/** <br/> * parse output attributes <br/> * @ return <br/> */<br/> private void processallattrs (stringbuffer SB) {<br/> for (INT I = 0; I <colnames. length; I ++) {<br/> Sb. append ("/tprivate" + sqltype2javatype (coltypes [I]) + "<br/> + colnames [I] +";/R/N "); </P> <p >}< br/>}</P> <p>/** <br/> * change the first letter of the input string to uppercase. <br/> * <br/> * @ Param STR <br/> * @ return <br/> */<br/> private string initcap (string Str) {<br/> char [] CH = Str. tochararray (); <br/> If (CH [0]> = 'A' & Ch [0] <= 'Z ') {<br/> CH [0] = (char) (CH [0]-32); <br/>}< br/> return new string (CH ); <br/>}</P> <p> private string sqltype2javatype (string sqltype) {<br/> If (sqltype. equalsignorecase ("bit") {<br/> return "bool"; <br/>}else if (sqltype. equalsignorecase ("tinyint") {<br/> return "Byte"; <br/>} else if (sqltype. inclusignorecase ("smallint") {<br/> return "short"; <br/>} else if (sqltype. equalsignorecase ("int") {<br/> return "int"; <br/>}else if (sqltype. equalsignorecase ("bigint") {<br/> return "long"; <br/>} else if (sqltype. equalsignorecase ("float") {<br/> return "float"; <br/>} else if (sqltype. equalsignorecase ("decimal") <br/> | sqltype. equalsignorecase ("numeric") <br/> | sqltype. repeated signorecase ("real") {<br/> return "double"; <br/>}else if (sqltype. equalsignorecase ("money") <br/> | sqltype. repeated signorecase ("smallmoney") {<br/> return "double"; <br/>} else if (sqltype. equalsignorecase ("varchar") <br/> | sqltype. equalsignorecase ("char") <br/> | sqltype. equalsignorecase ("nvarchar") <br/> | sqltype. equalsignorecase ("nchar") {<br/> return "string"; <br/>} else if (sqltype. equalsignorecase ("datetime") {<br/> return "date"; <br/>}</P> <p> else if (sqltype. repeated signorecase ("image") {<br/> return "blob"; <br/>}else if (sqltype. repeated signorecase ("text") {<br/> return "clob"; <br/>}< br/> return NULL; <br/>}</P> <p> Public static void main (string [] ARGs) {<br/> New genentitytool (); <br/>}< br/>