自动生成Java实体类

JDBC读取数据库元数据,生成JAVA实体类

package com.qinya.util;

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;

public class GenEntityTool {
    private String tablename = "petDiary";

    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() {
        Connection conn = DBSession.getConnection(); // 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 {
            DBSession.closeConnection(conn);
        }
    }

    /**
    * 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();
    }
}

评论

2 楼 影非弦 2013-05-20  

多谢分享，今天老师刚被布置的任务让实现自动生成java实体类代码，然后回来就找到您分享的这个，太感谢了，我自己肯定想不出来这么健壮的代码，写的很好，很有逻辑，这正是我所需要学习的，嘿嘿

1 楼 kukulxd 2011-10-11