JDBC读取数据库元数据,生成JAVA实体类

来源：互联网发布：mac dts 编辑：程序博客网时间：2024/05/11 05:45
package com.nrjh;import java.io.FileWriter;import java.io.IOException;import java.io.PrintWriter;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSetMetaData;import java.sql.SQLException;//import com.nffish.common.DBSession;import com.nrjh.commonality.dao.CommonDAO;public class GenEntityTool {    private String tablename = "T_SC_USERS";    private String[] colnames; // 列名数组    private String[] colTypes; // 列名类型数组    private int[] colSizes; // 列名大小数组    private boolean f_util = false; // 是否需要导入包java.util.*    private boolean f_sql = false; // 是否需要导入包java.sql.*    public GenEntityTool() {    CommonDAO commonDAO = new CommonDAO();        Connection conn = commonDAO.getConn(); // 得到数据库连接        String strsql = "select * from " + tablename;        try {            PreparedStatement pstmt = conn.prepareStatement(strsql);            ResultSetMetaData rsmd = pstmt.getMetaData();            int size = rsmd.getColumnCount(); // 共有多少列            colnames = new String[size];            colTypes = new String[size];            colSizes = new int[size];            for (int i = 0; i < rsmd.getColumnCount(); i++) {                colnames[i] = rsmd.getColumnName(i + 1);                colTypes[i] = rsmd.getColumnTypeName(i + 1);                if (colTypes[i].equalsIgnoreCase("datetime")) {                    f_util = true;                }                if (colTypes[i].equalsIgnoreCase("image")                        || colTypes[i].equalsIgnoreCase("text")) {                    f_sql = true;                }                colSizes[i] = rsmd.getColumnDisplaySize(i + 1);            }            String content = parse(colnames, colTypes, colSizes);            try {                FileWriter fw = new FileWriter(initcap(tablename) + ".java");                PrintWriter pw = new PrintWriter(fw);                pw.println(content);                pw.flush();                pw.close();            } catch (IOException e) {                e.printStackTrace();            }        } catch (SQLException e) {            e.printStackTrace();        } finally {//        conn.destroy();        }    }    /**    * 解析处理(生成实体类主体代码)    */    private String parse(String[] colNames, String[] colTypes, int[] colSizes) {        StringBuffer sb = new StringBuffer();        if (f_util) {            sb.append("import java.util.Date;\r\n");        }        if (f_sql) {            sb.append("import java.sql.*;\r\n\r\n\r\n");        }        sb.append("public class " + initcap(tablename) + " {\r\n");        processAllAttrs(sb);        processAllMethod(sb);        sb.append("}\r\n");        System.out.println(sb.toString());        return sb.toString();    }    /**    * 生成所有的方法    *     * @param sb    */    private void processAllMethod(StringBuffer sb) {        for (int i = 0; i < colnames.length; i++) {            sb.append("\tpublic void set" + initcap(colnames[i]) + "("                    + sqlType2JavaType(colTypes[i]) + " " + colnames[i]                    + "){\r\n");            sb.append("\t\tthis." + colnames[i] + "=" + colnames[i] + ";\r\n");            sb.append("\t}\r\n");            sb.append("\tpublic " + sqlType2JavaType(colTypes[i]) + " get"                    + initcap(colnames[i]) + "(){\r\n");            sb.append("\t\treturn " + colnames[i] + ";\r\n");            sb.append("\t}\r\n");        }    }    /**    * 解析输出属性    *     * @return    */    private void processAllAttrs(StringBuffer sb) {        for (int i = 0; i < colnames.length; i++) {            sb.append("\tprivate " + sqlType2JavaType(colTypes[i]) + " "                    + colnames[i] + ";\r\n");        }    }    /**    * 把输入字符串的首字母改成大写    *     * @param str    * @return    */    private String initcap(String str) {        char[] ch = str.toCharArray();        if (ch[0] >= 'a' && ch[0] <= 'z') {            ch[0] = (char) (ch[0] - 32);        }        return new String(ch);    }    private String sqlType2JavaType(String sqlType) {        if (sqlType.equalsIgnoreCase("bit")) {            return "bool";        } else if (sqlType.equalsIgnoreCase("tinyint")) {            return "byte";        } else if (sqlType.equalsIgnoreCase("smallint")) {            return "short";        } else if (sqlType.equalsIgnoreCase("int")) {            return "int";        } else if (sqlType.equalsIgnoreCase("bigint")) {            return "long";        } else if (sqlType.equalsIgnoreCase("float")) {            return "float";        } else if (sqlType.equalsIgnoreCase("decimal")                || sqlType.equalsIgnoreCase("numeric")                || sqlType.equalsIgnoreCase("real")) {            return "double";        } else if (sqlType.equalsIgnoreCase("money")                || sqlType.equalsIgnoreCase("smallmoney")) {            return "double";        } else if (sqlType.equalsIgnoreCase("varchar")                || sqlType.equalsIgnoreCase("char")                || sqlType.equalsIgnoreCase("nvarchar")                || sqlType.equalsIgnoreCase("nchar")) {            return "String";        } else if (sqlType.equalsIgnoreCase("datetime")) {            return "Date";        }        else if (sqlType.equalsIgnoreCase("image")) {            return "Blob";        } else if (sqlType.equalsIgnoreCase("text")) {            return "Clob";        }        return null;    }    public static void main(String[] args) {        new GenEntityTool();    }}
转自:http://blog.csdn.net/v1v1wang/article/details/5672296
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