数据库表生成MyBatis对应的java类

vike681

　　当数据库中表有多个的时候，写数据库表对应的entity类是一个工作量不小的事情，所以能自动化把数据表生成对应的Java类，有一定的意义(Save Time):

/**
* Created by jiangzhiqiang on 16/3/24.
*/
import java.io.File;
import java.io.FileOutputStream;
import java.io.PrintWriter;
import java.sql.*;
import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;
public class TableToBean {
private static final String LINE = "\r\n";
private static final String TAB = "\t";
String rootPath = "/Users/jiangzhiqiang/dev";

private static Map<String, String> map;
static {
map = new HashMap<String, String>();
map.put("VARCHAR", "String");
map.put("INT", "Integer");
map.put("SMALLINT", "Integer");
map.put("FLOAT", "float");
map.put("TIMESTAMP", "Date");
map.put("CHAR", "String");
map.put("DATETIME", "Date");
map.put("DATE", "Date");
map.put("TIMESTAMP_IMPORT", "import java.util.Date");
map.put("DATETIME_IMPORT", "import java.util.Date");
map.put("BIGINT", "Long");
map.put("TINYINT", "Integer");
map.put("DECIMAL", "Double");
}
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 + " limit 1"; //MySql DB
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("public class " + tableName + " {");
sb.append(LINE);
defProperty(md, columnCount, sb);
genSetGet(md, columnCount, sb);
sb.append("}");
buildJavaFile(rootPath + "/" + tableName + ".java", sb.toString());
// linux平台, 不需要把"/"转成"\\"
}
//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);
break;
}
}
}
//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;
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java文件出错：" + e.getMessage());
}
}
public static void main(String[] args) throws SQLException, ClassNotFoundException {
String jdbcString = "jdbc:mysql://m3307i.test.db.dmall.com:3307/dmall_settle";
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection(jdbcString, "devtest", "WDevTest@Dmall");
DatabaseMetaData databaseMetaData = con.getMetaData();
String[] tableType = {"TABLE"};
ResultSet rs = databaseMetaData.getTables(null, null, "%", tableType);
TableToBean d = new TableToBean();
while (rs.next()) {
String tableName = rs.getString(3).toString();
d.tableToBean(con, tableName);
}
}
}

　　Linux和Mac环境下，上面的tableToBean方法需要略做变动，段尾的代码换成：

String endPath = rootPath + (packages.replace(".", "/"));
buildJavaFile(endPath + "/" + tableName + ".java", sb.toString());
　　备注： 此Code摘自互联网，略作修改而成。