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云代码 - java代码库

Mybaits根据数据库生成实体类——GenerateJavaFileUtils

2018-05-07 作者： 起湾道辉哥举报

[java]代码库

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import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
 
public class GenerateJavaFileUtils {
 
    private String tablename = "";
    private String[] colnames;
    private String[] colTypes;
    private int[] colSizes; // 列名大小
    private int[] colScale; // 列名小数精度
    private boolean importUtil = false;
    private boolean importSql = false;
    private boolean importMath = false;
 
    /**
     * @param args
     */
    public void tableToEntity(String tName) {
        tablename = tName;
        // 数据连Connection获取,自己想办法就行.
        Connection conn = getConnection();
        String strsql = "SELECT * FROM " + tablename;// +" WHERE ROWNUM=1"
        // 读一行记录;
        try {
            System.out.println(strsql);
            PreparedStatement pstmt = conn.prepareStatement(strsql);
            pstmt.executeQuery();
            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];
            colScale = new int[size];
            for (int i = 0; i < rsmd.getColumnCount(); i++) {
                rsmd.getCatalogName(i + 1);
                colnames[i] = rsmd.getColumnName(i + 1).toLowerCase();
                colTypes[i] = rsmd.getColumnTypeName(i + 1).toLowerCase();
                colScale[i] = rsmd.getScale(i + 1);
                System.out.println(rsmd.getCatalogName(i + 1));
                if ("datetime".equals(colTypes[i])) {
                    importUtil = true;
                }
                if ("image".equals(colTypes[i]) || "text".equals(colTypes[i])) {
                    importSql = true;
                }
                if (colScale[i] > 0) {
                    importMath = true;
                }
                colSizes[i] = rsmd.getPrecision(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 {
            releaseConnection(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();
        sb.append("\r\nimport java.io.Serializable;\r\n");
        if (importUtil) {
            sb.append("import java.util.Date;\r\n");
        }
        if (importSql) {
            sb.append("import java.sql.*;\r\n\r\n");
        }
        if (importMath) {
            sb.append("import java.math.*;\r\n\r\n");
        }
        // 表注释
        processColnames(sb);
        sb.append("public class " + initcap(tablename) + " implements Serializable {\r\n");
        processAllAttrs(sb);
        processAllMethod(sb);
        sb.append("}\r\n");
        System.out.println(sb.toString());
        return sb.toString();
 
    }
 
    /**
     * 处理列名,把空格下划线'_'去掉,同时把下划线后的首字母大写 要是整个列在3个字符及以内,则去掉'_'后,不把"_"后首字母大写.
     * 同时把数据库列名,列类型写到注释中以便查看,
     *
     * @param sb
     */
    private void processColnames(StringBuffer sb) {
        sb.append("\r\n/** " + tablename + "\r\n");
        String colsiz = "";
        for (int i = 0; i < colnames.length; i++) {
            colsiz = colSizes[i] <= 0 ? ""
                    : (colScale[i] <= 0 ? "(" + colSizes[i] + ")" : "(" + colSizes[i] + "," + colScale[i] + ")");
            sb.append("\t" + colnames[i].toUpperCase() + " " + colTypes[i].toUpperCase() + colsiz + "\r\n");
            char[] ch = colnames[i].toCharArray();
            char c = 'a';
            if (ch.length > 3) {
                for (int j = 0; j < ch.length; j++) {
                    c = ch[j];
                    if (c == '_') {
                        if (ch[j + 1] >= 'a' && ch[j + 1] <= 'z') {
                            ch[j + 1] = (char) (ch[j + 1] - 32);
                        }
                    }
                }
            }
            String str = new String(ch);
            colnames[i] = str.replaceAll("_", "");
        }
        sb.append("*/\r\n");
    }
 
    /**
     * 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]) + "("
                    + oracleSqlType2JavaType(colTypes[i], colScale[i], colSizes[i]) + " " + colnames[i] + "){\r\n");
            sb.append("\t\tthis." + colnames[i] + "=" + colnames[i] + ";\r\n");
            sb.append("\t}\r\n");
 
            sb.append("\tpublic " + oracleSqlType2JavaType(colTypes[i], colScale[i], colSizes[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) {
        sb.append("\tprivate static final long serialVersionUID = 1L;\r\n");
        for (int i = 0; i < colnames.length; i++) {
            sb.append("\tprivate " + oracleSqlType2JavaType(colTypes[i], colScale[i], colSizes[i]) + " " + colnames[i]
                    + ";\r\n");
        }
        sb.append("\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);
    }
 
    /**
     * Oracle
     *
     * @param sqlType
     * @param scale
     * @return
     */
    private String oracleSqlType2JavaType(String sqlType, int scale, int size) {
        if (sqlType.equals("int")) {
            return "Integer";
        } else if (sqlType.equals("bigint")) {
            return "Long";
        } else if (sqlType.equals("float") || sqlType.equals("float precision"))
            return "Float";
        else if (sqlType.equals("double") || sqlType.equals("double precision")) {
            return "Double";
        } else if (sqlType.equals("number") || sqlType.equals("decimal") || sqlType.equals("numeric")
                || sqlType.equals("real")) {
            return scale == 0 ? (size < 10 ? "Integer" : "Long") : "Double";
        } else if (sqlType.equals("varchar") || sqlType.equals("varchar2") || sqlType.equals("char")
                || sqlType.equals("nvarchar") || sqlType.equals("nchar")) {
            return "String";
        } else if (sqlType.equals("datetime") || sqlType.equals("date") || sqlType.equals("timestamp")) {
            return "Date";
        }
        return null;
    }
 
    /**
     * 自动获取jcbc链接
     */
    protected static Connection getConnection() {
        Connection localConnection = null;
        try {
            Class.forName("com.mysql.jdbc.Driver");
            localConnection = DriverManager.getConnection("jdbc:mysql://192.168.1.110:3306/jymh", "root", "root123");
            localConnection.setAutoCommit(false);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return localConnection;
    }
 
    /**
     * 释放jdbc链接
     *
     * @param conn
     */
    protected static void releaseConnection(Connection conn) {
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            conn = null;
        }
    }
 
    /**
     * @param args
     */
    public static void main(String[] args) {
        GenerateJavaFileUtils t = new GenerateJavaFileUtils();
        t.tableToEntity("local_order_code");
    }
}


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