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作者:php-note.com  发布于:2018-06-19 16:30  分类:Java  编辑

utils/GenEntityMysql.java

package utils;

import java.io.File;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.text.SimpleDateFormat;
import java.util.Date;

public class GenEntityMysql {
    private static final GenEntityMysql INSTANCE = new GenEntityMysql();

    private String tableName;            // 表名
    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 needUtil = false;   // 是否需要导入包java.util.*
    private boolean needSql = false;    // 是否需要导入包java.sql.*
    private static final SimpleDateFormat SDF = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    private static final String SQL = "SELECT * FROM "; // 数据库操作

    // TODO 需要修改的地方
    private static final String URL = "jdbc:mysql://127.0.0.1:3306/yxyk-golo";
    private static final String NAME = "root";
    private static final String PASS = "123456";
    private static final String DRIVER = "com.mysql.jdbc.Driver";
    private String packagePath = "com.yxyk.golo.entity";     // 实体包名
    private String packageOutPath = "main/java/com/yxyk/golo/entity";    // 实体生成(src目录)路径
    private String authorName = "php-note.com";             // 作者名字

    /**
     * 类的构造方法
     */
    private GenEntityMysql() {
    }

    /**
     * 生成class的所有内容
     */
    private String parse() {
        StringBuffer sb = new StringBuffer();
        sb.append("package " + packagePath + ";\r\n");
        sb.append("\r\n");
        
        // 判断是否导入工具包
        if (needUtil) {
            sb.append("import java.util.Date;\r\n");
        }
        if (needSql) {
            sb.append("import java.sql.*;\r\n");
        }
        
        // 注释部分
        sb.append("\r\n/**\r\n");
        sb.append(" * 表名: " + tableName + "\r\n");
        sb.append(" * \r\n");
        sb.append(" * @author " + authorName + "\r\n");
        sb.append(" * @since " + SDF.format(new Date()) + "\r\n");
        sb.append(" */ \r\n");
        
        // 实体部分
        sb.append("public class " + getTransStr(tableName, true) + " {\r\n");
        processAllAttrs(sb); // 属性
        processAllMethod(sb); // get set方法
        sb.append("}");
        
        return sb.toString();
    }

    /**
     * 生成所有成员变量
     */
    private void processAllAttrs(StringBuffer sb) {
        for (int i = 0; i < colNames.length; i++) {
            sb.append("    private " + sqlType2JavaType(colTypes[i]) + " " + getTransStr(colNames[i], false) + ";\r\n");
        }
    }

    /**
     * 生成所有get/set方法
     */
    private void processAllMethod(StringBuffer sb) {
        for (int i = 0; i < colNames.length; i++) {
            sb.append("\r\n    public void set" + getTransStr(colNames[i], true) + "(" + sqlType2JavaType(colTypes[i]) + " "
                    + getTransStr(colNames[i], false) + ") {\r\n");
            sb.append("        this." + getTransStr(colNames[i], false) + " = " + getTransStr(colNames[i], false) + ";\r\n");
            sb.append("    }\r\n\r\n");
            sb.append("    public " + sqlType2JavaType(colTypes[i]) + " get" + getTransStr(colNames[i], true) + "() {\r\n");
            sb.append("        return " + getTransStr(colNames[i], false) + ";\r\n");
            sb.append("    }\r\n");
        }
    }

    /**
     * 将传入字符串的首字母转成大写
     */
    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);
    }

    /**
     * 将mysql中表名和字段名转换成驼峰形式
     */
    private String getTransStr(String before, boolean firstChar2Upper) {
        // 不带"_"的字符串,则直接首字母大写后返回
        if (!before.contains("_"))
            return firstChar2Upper ? initCap(before) : before;
        String[] strs = before.split("_");
        StringBuffer after = null;
        if (firstChar2Upper) {
            after = new StringBuffer(initCap(strs[0]));
        } else {
             after = new StringBuffer(strs[0]);
        }
        for (int i=1; i<strs.length; i++)
            after.append(initCap(strs[i]));
        return after.toString();
    }

    /**
     * 查找sql字段类型所对应的Java类型
     */
    private String sqlType2JavaType(String sqlType) {
        if (sqlType.equalsIgnoreCase("bit")) {
            return "boolean";
        } else if (sqlType.equalsIgnoreCase("tinyint")) {
            return "byte";
        } else if (sqlType.equalsIgnoreCase("smallint")) {
            return "short";
        } else if (sqlType.equalsIgnoreCase("int") || sqlType.equalsIgnoreCase("INTEGER")) {
            return "Integer";
        } 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") || sqlType.equalsIgnoreCase("money")
                || sqlType.equalsIgnoreCase("smallmoney")) {
            return "double";
        } else if (sqlType.equalsIgnoreCase("varchar") || sqlType.equalsIgnoreCase("char")
                || sqlType.equalsIgnoreCase("nvarchar") || sqlType.equalsIgnoreCase("nchar")
                || sqlType.equalsIgnoreCase("text")) {
            return "String";
        } else if (sqlType.equalsIgnoreCase("datetime")||sqlType.equalsIgnoreCase("timestamp")) {
            return "Date";
        } else if (sqlType.equalsIgnoreCase("image")) {
            return "Blod";
        }
        return null;
    }

    /**
     * 生成方法
     */
    private void generate() throws Exception {
        // 与数据库的连接
        Connection con;
        PreparedStatement pStemt = null;
        Class.forName(DRIVER);
        con = DriverManager.getConnection(URL, NAME, PASS);
        System.out.println("connect database success...");
        
        // 获取数据库的元数据
        DatabaseMetaData db = con.getMetaData();
        
        // 从元数据中获取到所有的表名
        ResultSet rs = db.getTables(null, null, null, new String[] { "TABLE" });
        String tableSql;
        PrintWriter pw = null;
        while (rs.next()) {
            tableName = rs.getString(3);
            tableSql = SQL + tableName;
            pStemt = con.prepareStatement(tableSql);
            ResultSetMetaData rsmd = pStemt.getMetaData();
            int size = rsmd.getColumnCount();
            colNames = new String[size];
            colTypes = new String[size];
            colSizes = new int[size];
            
            // 获取所需的信息
            for (int i = 0; i < size; i++) {
                colNames[i] = rsmd.getColumnName(i + 1);
                colTypes[i] = rsmd.getColumnTypeName(i + 1);
                if (colTypes[i].equalsIgnoreCase("datetime")) {
                    needUtil = true;
                }
                if (colTypes[i].equalsIgnoreCase("image") || colTypes[i].equalsIgnoreCase("text")) {
                    needSql = true;
                }
                colSizes[i] = rsmd.getColumnDisplaySize(i + 1);
            }
            
            // 解析生成class的所有内容
            String content = parse();
            
            // 输出生成文件
            File directory = new File("");
            String outputPath = directory.getAbsolutePath() + "/src/" + packageOutPath
                    + "/" + getTransStr(tableName, true) + ".java";
            FileWriter fw = new FileWriter(outputPath);
            pw = new PrintWriter(fw);
            pw.println(content);
            pw.flush();
            System.out.println("create class >>>>> " + tableName);
        }
        if (pw != null)
            pw.close();
    }

    /**
     * 执行方法
     */
    public static void main(String[] args) {
        try {
            INSTANCE.generate();
            System.out.println("generate classes success!");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}