本文共 7463 字，大约阅读时间需要 24 分钟。
2007年05月29日 16:44:00步骤：通过DataBaseMetaData一次获取想要的各个表和相关的列信息。
再分析各个列的类型，生成文件。
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非常简单，只需要读一次数据库，同样的原理可以来实现DAO层。
配合几个利用元数据和反射来处理DTO和DAO,即可实现简单的ORM.
正在实验中...
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import java.io.File;import java.io.FileWriter;import java.io.IOException;import java.sql.Connection;import java.sql.DatabaseMetaData;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import java.util.Date;import java.util.HashMap;import java.util.Iterator;import java.util.List;import java.util.Set;import java.util.Map.Entry; /** * @author KimmKing */public class test {private static final String T = "/t";
private static final String CRLF = "/r/n";
static String driverName = "sun.jdbc.odbc.JdbcOdbcDriver";
static String url = "jdbc:odbc:qsoft";
static String user = "sa";
static String password = "q11";
static HashMap map = new HashMap();
static HashMap type = new HashMap();
static { type.put("4", "int"); type.put("12", "String"); type.put("93", "Date"); type.put("-1", "String"); }static String path = "d://DTO";
public static void main(String[] args) {
// testODBC();findTableAndColumn();
Set set = map.entrySet(); for (Iterator iter = set.iterator(); iter.hasNext();) { Entry element = (Entry) iter.next(); TableBean table = (TableBean) element.getValue(); createDto(table); } }private static void createDto(TableBean table) {
StringBuffer sb = new StringBuffer();
StringBuffer tostring = new StringBuffer();sb.append("package com.qsoft.dto;");
sb.append(CRLF); sb.append(CRLF);sb.append("/**");
sb.append(CRLF); sb.append(" * @author KimmKing"); sb.append(CRLF); sb.append(" * create time:" + new Date().toLocaleString()); sb.append(CRLF); sb.append("*/"); sb.append(CRLF); sb.append(CRLF);sb.append("import java.util.Date;");
sb.append(CRLF); sb.append(CRLF);String tablename = table.getName();
String classname = convertT2C(tablename); List list = table.getColumns();// tostring.append(classname);
// tostring.append("["); sb.append("public class " + classname + " implements IDto {"); sb.append(CRLF);for (Iterator iter = list.iterator(); iter.hasNext();) {
ColumnBean column = (ColumnBean) iter.next();String columnname = column.getName().toLowerCase();
String stype = type.get(column.getType() + "").toString();
sb.append(T); sb.append("private " + stype + " " + columnname + ";"); sb.append(T); sb.append("//Length:"); sb.append(column.getLength()); sb.append(CRLF);sb.append(CRLF);
// getter
sb.append(T); sb.append("public " + stype + " " + getGetter(columnname) + "() {"); sb.append(CRLF);sb.append(T);
sb.append(T); sb.append("return " + columnname + ";"); sb.append(CRLF);sb.append(T);
sb.append("}"); sb.append(CRLF);sb.append(CRLF);
// setter
sb.append(T); sb.append("public void " + getSetter(columnname) + "(" + stype + " _" + columnname + ") {"); sb.append(CRLF);sb.append(T);
sb.append(T); sb.append("this." + columnname + "=_" + columnname + ";"); sb.append(CRLF);sb.append(T);
sb.append("}"); sb.append(CRLF);sb.append(CRLF);
sb.append(CRLF); // tostring.append("/"," + columnname + "=/" + " + columnname + " + ");}
String pv = tostring.toString(); pv = pv.substring(2);// toString sb.append(T); sb.append("public String toString() {"); sb.append(CRLF);sb.append(T);
sb.append(T); sb.append("return /"" + classname + "[" + pv + "/"]/";"); sb.append(CRLF);sb.append(T);
sb.append("}"); sb.append(CRLF);sb.append(CRLF);
sb.append("}");
sb.append(CRLF);File dir = new File(path);
if (!dir.exists()) dir.mkdirs();File file = new File(path + "//" + classname + ".java");
try {FileWriter writer = new FileWriter(file);
writer.write(sb.toString()); writer.close();} catch (IOException e) {
e.printStackTrace(); }}
private static String convertT2C(String tablename) {
String classname = tablename.substring(1).toUpperCase();String first = classname.substring(0,1).toUpperCase();
classname = first + classname.substring(1).toLowerCase() + "Dto";return classname;
}private static String getSetter(String propertyName) {
String first = propertyName.substring(0, 1).toUpperCase();
String methodName = "set" + first + propertyName.substring(1).toLowerCase();return methodName;
}private static String getGetter(String propertyName) {
String first = propertyName.substring(0, 1).toUpperCase();
String methodName = "get" + first + propertyName.substring(1).toLowerCase();return methodName;
}private static void findTableAndColumn() {
try {
Class.forName(driverName); Connection conn = DriverManager.getConnection(url, user, password);DatabaseMetaData meta = conn.getMetaData();
ResultSet rs = meta.getColumns(null, null, "c%", null);while (rs.next()) {
String tablename = rs.getString(3);
TableBean table = (TableBean) map.get(tablename); if (table == null) { table = new TableBean(); table.setName(tablename); map.put(tablename, table); }ColumnBean column = new ColumnBean();
column.setName(rs.getString(4)); column.setType(rs.getInt(5)); column.setLength(rs.getInt(7)); table.getColumns().add(column); }rs.close();
conn.close();} catch (ClassNotFoundException e) {
e.printStackTrace(); } catch (SQLException ex) { ex.printStackTrace(); }}
private static void testmeta() {
// String sql = "select * from cuser ";
try {
Class.forName(driverName); Connection conn = DriverManager.getConnection(url, user, password);DatabaseMetaData meta = conn.getMetaData();
ResultSet rs = meta.getColumns(null, null, "c%", null);while (rs.next()) {
print(rs); System.out.println(); }conn.close();
} catch (ClassNotFoundException e) {
e.printStackTrace(); } catch (SQLException ex) { ex.printStackTrace(); } }private static void print(ResultSet rs) {
try {
int count = rs.getMetaData().getColumnCount(); for (int i = 0; i > count; i++) { System.out.print(rs.getString(1 + i)); System.out.print("/t"); } } catch (SQLException e) { e.printStackTrace(); }}
private static void testODBC() {
String sql = "select * from cuser ";
try {
Class.forName(driverName); Connection conn = DriverManager.getConnection(url, user, password); Statement stmt = conn.createStatement();ResultSet rs = stmt.executeQuery(sql);
while (rs.next()) { System.out.println(rs.getString(2)); }rs.close();
stmt.close(); conn.close();} catch (ClassNotFoundException e) {
e.printStackTrace(); } catch (SQLException ex) { ex.printStackTrace(); } }private static void print(List list) {
for (Iterator iter = list.iterator(); iter.hasNext();) {
System.out.println(iter.next()); }}
}
/**
* @author KimmKing * */public class ColumnBean {
private String name;
private int type; private int length; public int getLength() { return length; } public void setLength(int length) { this.length = length; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getType() { return type; } public void setType(int type) { this.type = type; } }
import java.util.ArrayList;
import java.util.List;
/**
* @author KimmKing * */public class TableBean {private String name;
private List columns = new ArrayList(); public List getColumns() { return columns; } public void setColumns(List columns) { this.columns = columns; } public String getName() { return name; } public void setName(String name) { this.name = name; } }
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