java 数据库表反向生成相应的java类

ゞ浴缸里的玫瑰 2022-08-26 11:05 190阅读 0赞

java 数据库表反向生成相应的java类,同时完成了字段和表名中包含下划线的情况。

package cn.tongkuan.common;
    
    import java.io.File;
    import java.io.FileOutputStream;
    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.sql.SQLException;
    import java.util.HashMap;
    import java.util.Map;
    import java.util.StringTokenizer;
    
     
    public class TableToJavaBean {
    
    	private static final String LINE = "\r\n";
    	private static final String TAB = "\t";
    	String packages = this.getClass().getPackage().getName().replace("common", "model");;
    	private static Map<String, String> map;
    
    	static {
    		map = new HashMap<String, String>();
    		map.put("VARCHAR", "String");
    		map.put("INTEGER", "Integer");
    		map.put("FLOAT", "float");
    		map.put("TIMESTAMP", "Date");
    		map.put("CHAR", "String");
    		map.put("DATETIME", "Date");
    		map.put("TIMESTAMP_IMPORT", "import java.util.Date");
    		map.put("DATETIME_IMPORT","import java.util.Date");
    	}
    
    	public static String getPojoType(String dataType) {
    		StringTokenizer st = new StringTokenizer(dataType);
    		return map.get(st.nextToken());
    	}
    	
    	public static String getImport(String dataType) {
    		if (map.get(dataType)==null||"".equals(map.get(dataType))) {
    		   return null;	
    		}else{
    		   return map.get(dataType);
    		}
    	}
    
     
    	public void tableToBean(Connection connection, String tableName) throws SQLException {
    		String sql = "select * from " + tableName + " where 1 <> 1";
    		PreparedStatement ps = null;
    		ResultSet rs = null;
    		ps = connection.prepareStatement(sql);
    		rs = ps.executeQuery();
    		ResultSetMetaData md = rs.getMetaData();
    		int columnCount = md.getColumnCount();
    		StringBuffer sb = new StringBuffer();
    		tableName = tableName.substring(0, 1).toUpperCase() + tableName.subSequence(1, tableName.length());
    		tableName = this.dealLine(tableName);
    		sb.append("package " + this.packages + " ;");
    		sb.append(LINE);
    		importPackage(md, columnCount, sb);
    		sb.append(LINE);
    		sb.append(LINE);
    		sb.append("public class " + tableName + " {");
    		sb.append(LINE);
    		defProperty(md, columnCount, sb);
    		genSetGet(md, columnCount, sb);
    		sb.append("}");
    		String paths = System.getProperty("user.dir");
    		String endPath = paths + "\\src\\" + (packages.replace("/", "\\")).replace(".", "\\");
    		buildJavaFile(endPath + "\\" + tableName + ".java", sb.toString());
    	}
    	//属性生成get、 set 方法
    	private void genSetGet(ResultSetMetaData md, int columnCount, StringBuffer sb) throws SQLException {
    		for (int i = 1; i <= columnCount; i++) {
    			sb.append(TAB);
    			String pojoType = getPojoType(md.getColumnTypeName(i));
    			String columnName = dealLine(md, i);
    			String getName = null;
    			String setName = null;
    			if (columnName.length() > 1) {
    				getName = "public " + pojoType + " get" + columnName.substring(0, 1).toUpperCase()
    						+ columnName.substring(1, columnName.length()) + "() {";
    				setName = "public void set" + columnName.substring(0, 1).toUpperCase()
    						+ columnName.substring(1, columnName.length()) + "(" + pojoType + " " + columnName + ") {";
    			} else {
    				getName = "public get" + columnName.toUpperCase() + "() {";
    				setName = "public set" + columnName.toUpperCase() + "(" + pojoType + " " + columnName + ") {";
    			}
    			sb.append(LINE).append(TAB).append(getName);
    			sb.append(LINE).append(TAB).append(TAB);
    			sb.append("return " + columnName + ";");
    			sb.append(LINE).append(TAB).append("}");
    			sb.append(LINE);
    			sb.append(LINE).append(TAB).append(setName);
    			sb.append(LINE).append(TAB).append(TAB);
    			sb.append("this." + columnName + " = " + columnName + ";");
    			sb.append(LINE).append(TAB).append("}");
    			sb.append(LINE);
    
    		}
    	}
    	
    	//导入属性所需包
    	private void importPackage(ResultSetMetaData md, int columnCount, StringBuffer sb) throws SQLException {
    		for (int i = 1; i <= columnCount; i++) {
    			String im=getImport(md.getColumnTypeName(i)+"_IMPORT");
    			if (im!=null) {
    				sb.append(im+ ";");
    				sb.append(LINE);
    			}
    		}
    	}
    	//属性定义
    	private void defProperty(ResultSetMetaData md, int columnCount, StringBuffer sb) throws SQLException {
    		
    		for (int i = 1; i <= columnCount; i++) {
    			sb.append(TAB);
    			String columnName = dealLine(md, i);
    			sb.append("private " + getPojoType(md.getColumnTypeName(i)) + " " + columnName + ";");
    			sb.append(LINE);
    		}
    	}
    
    	private String dealLine(ResultSetMetaData md, int i) throws SQLException {
    		String columnName = md.getColumnName(i);
    		// 处理下划线情况，把下划线后一位的字母变大写；
    		columnName = dealName(columnName);
    		return columnName;
    	}
    
    	private String dealLine(String tableName) {
    		// 处理下划线情况，把下划线后一位的字母变大写；
    		tableName = dealName(tableName);
    		return tableName;
    	}
    	//下划线后一位字母大写
    	private String dealName(String columnName) {
    		if (columnName.contains("_")) {
    			StringBuffer names = new StringBuffer();
    			String arrayName[] = columnName.split("_");
    			names.append(arrayName[0]);
    			for (int i = 1; i < arrayName.length; i++) {
    				String arri=arrayName[i];
    				String tmp=arri.substring(0, 1).toUpperCase()+ arri.substring(1, arri.length());
    				names.append(tmp);
    			}
    			columnName=names.toString();
    		}
    		return columnName;
    	}
    	//生成java文件
    	public void buildJavaFile(String filePath, String fileContent) {
    		try {
    			File file = new File(filePath);
    			FileOutputStream osw = new FileOutputStream(file);
    			PrintWriter pw = new PrintWriter(osw);
    			pw.println(fileContent);
    			pw.close();
    		} catch (Exception e) {
    			System.out.println("生成txt文件出错：" + e.getMessage());
    		}
    	}
    
    	public static void main(String[] args) throws SQLException, ClassNotFoundException {
    		String jdbcString = "jdbc:mysql://192.168.224.1/test";
    		Class.forName("com.mysql.jdbc.Driver");
    		Connection con = DriverManager.getConnection(jdbcString, "root", "root");
    		DatabaseMetaData databaseMetaData = con.getMetaData();
    		String[] tableType = { "TABLE" };
    		ResultSet rs = databaseMetaData.getTables(null, null, "%",tableType);
    		TableToJavaBean d = new TableToJavaBean();
    		while(rs.next()){
    			String tableName=rs.getString(3).toString();
    			d.tableToBean(con,tableName);
    		}
    	}
    }