1 package com.easyrail.base.dao;
2
3 import java.io.Serializable;
4 import java.lang.reflect.Field;
5 import java.lang.reflect.ParameterizedType;
6 import java.sql.Types;
7 import java.util.LinkedHashMap;
8 import java.util.List;
9 import java.util.Map;
10
11 import org.springframework.jdbc.core.BeanPropertyRowMapper;
12 import org.springframework.jdbc.core.JdbcTemplate;
13 import org.springframework.jdbc.core.RowMapper;
14
15 public abstract class BaseDaoImpl<T>{
16 /** 设置一些操作的常量 */
17 public static final String SQL_INSERT = "insert";
18 public static final String SQL_UPDATE = "update";
19 public static final String SQL_DELETE = "delete";
20
21 private JdbcTemplate jdbcTemplate;
22
23 public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
24 this.jdbcTemplate = jdbcTemplate;
25 }
26
27 private Class<T> entityClass;
28
29 @SuppressWarnings("unchecked")
30 public BaseDaoImpl() {
31 ParameterizedType type = (ParameterizedType) getClass().getGenericSuperclass();
32 entityClass = (Class<T>) type.getActualTypeArguments()[0];
33 System.out.println("Dao实现类是：" + entityClass.getName());
34 }
35
36 public void save(T entity) {
37 String sql = this.makeSql(SQL_INSERT);
38 Object[] args = this.setArgs(entity, SQL_INSERT);
39 int[] argTypes = this.setArgTypes(entity, SQL_INSERT);
40 jdbcTemplate.update(sql.toString(), args, argTypes);
41 }
42
43 public void update(T entity) {
44 String sql = this.makeSql(SQL_UPDATE);
45 Object[] args = this.setArgs(entity, SQL_UPDATE);
46 int[] argTypes = this.setArgTypes(entity, SQL_UPDATE);
47 jdbcTemplate.update(sql, args, argTypes);
48 }
49
50 public void delete(T entity) {
51 String sql = this.makeSql(SQL_DELETE);
52 Object[] args = this.setArgs(entity, SQL_DELETE);
53 int[] argTypes = this.setArgTypes(entity, SQL_DELETE);
54 jdbcTemplate.update(sql, args, argTypes);
55 }
56
57 public void delete(Serializable id) {
58 String sql = " DELETE FROM " + entityClass.getSimpleName() + " WHERE id=?";
59 jdbcTemplate.update(sql, id);
60 }
61
62 public void deleteAll() {
63 String sql = " TRUNCATE TABLE " + entityClass.getSimpleName();
64 jdbcTemplate.execute(sql);
65 }
66
67 public T findById(Serializable id) {
68 String sql = "SELECT * FROM " + entityClass.getSimpleName() + " WHERE id=?";
69 RowMapper<T> rowMapper = BeanPropertyRowMapper.newInstance(entityClass);
70 return jdbcTemplate.query(sql, rowMapper, id).get(0);
71 }
72
73 public List<T> findAll() {
74 String sql = "SELECT * FROM " + entityClass.getSimpleName();
75 RowMapper<T> rowMapper = BeanPropertyRowMapper.newInstance(entityClass);
76 return jdbcTemplate.query(sql, rowMapper);
77 }
78
79 // 组装SQL
80 private String makeSql(String sqlFlag) {
81 StringBuffer sql = new StringBuffer();
82 Field[] fields = entityClass.getDeclaredFields();
83 if (sqlFlag.equals(SQL_INSERT)) {
84 sql.append(" INSERT INTO " + entityClass.getSimpleName());
85 sql.append("(");
86 for (int i = 0; fields != null && i < fields.length; i++) {
87 fields[i].setAccessible(true); // 暴力反射
88 String column = fields[i].getName();
89 sql.append(column).append(",");
90 }
91 sql = sql.deleteCharAt(sql.length() - 1);
92 sql.append(") VALUES (");
93 for (int i = 0; fields != null && i < fields.length; i++) {
94 sql.append("?,");
95 }
96 sql = sql.deleteCharAt(sql.length() - 1);
97 sql.append(")");
98 } else if (sqlFlag.equals(SQL_UPDATE)) {
99 sql.append(" UPDATE " + entityClass.getSimpleName() + " SET ");
100 for (int i = 0; fields != null && i < fields.length; i++) {
101 fields[i].setAccessible(true); // 暴力反射
102 String column = fields[i].getName();
103 if (column.equals("id")) { // id 代表主键
104 continue;
105 }
106 sql.append(column).append("=").append("?,");
107 }
108 sql = sql.deleteCharAt(sql.length() - 1);
109 sql.append(" WHERE id=?");
110 } else if (sqlFlag.equals(SQL_DELETE)) {
111 sql.append(" DELETE FROM " + entityClass.getSimpleName() + " WHERE id=?");
112 }
113 System.out.println("SQL=" + sql);
114 return sql.toString();
115
116 }
117
118 // 设置参数
119 private Object[] setArgs(T entity, String sqlFlag) {
120 Field[] fields = entityClass.getDeclaredFields();
121 if (sqlFlag.equals(SQL_INSERT)) {
122 Object[] args = new Object[fields.length];
123 for (int i = 0; args != null && i < args.length; i++) {
124 try {
125 fields[i].setAccessible(true); // 暴力反射
126 args[i] = fields[i].get(entity);
127 } catch (Exception e) {
128 e.printStackTrace();
129 }
130 }
131 return args;
132 } else if (sqlFlag.equals(SQL_UPDATE)) {
133 Object[] tempArr = new Object[fields.length];
134 for (int i = 0; tempArr != null && i < tempArr.length; i++) {
135 try {
136 fields[i].setAccessible(true); // 暴力反射
137 tempArr[i] = fields[i].get(entity);
138 } catch (Exception e) {
139 e.printStackTrace();
140 }
141 }
142 Object[] args = new Object[fields.length];
143 System.arraycopy(tempArr, 1, args, 0, tempArr.length - 1); // 数组拷贝
144 args[args.length - 1] = tempArr[0];
145 return args;
146 } else if (sqlFlag.equals(SQL_DELETE)) {
147 Object[] args = new Object[1]; // 长度是1
148 fields[0].setAccessible(true); // 暴力反射
149 try {
150 args[0] = fields[0].get(entity);
151 } catch (Exception e) {
152 e.printStackTrace();
153 }
154 return args;
155 }
156 return null;
157
158 }
159
160 // 设置参数类型（写的不全，只是一些常用的）
161 private int[] setArgTypes(T entity, String sqlFlag) {
162 Field[] fields = entityClass.getDeclaredFields();
163 if (sqlFlag.equals(SQL_INSERT)) {
164 int[] argTypes = new int[fields.length];
165 try {
166 for (int i = 0; argTypes != null && i < argTypes.length; i++) {
167 fields[i].setAccessible(true); // 暴力反射
168 if (fields[i].get(entity).getClass().getName().equals("java.lang.String")) {
169 argTypes[i] = Types.VARCHAR;
170 } else if (fields[i].get(entity).getClass().getName().equals("java.lang.Double")) {
171 argTypes[i] = Types.DECIMAL;
172 } else if (fields[i].get(entity).getClass().getName().equals("java.lang.Integer")) {
173 argTypes[i] = Types.INTEGER;
174 } else if (fields[i].get(entity).getClass().getName().equals("java.util.Date")) {
175 argTypes[i] = Types.DATE;
176 }
177 }
178 } catch (Exception e) {
179 e.printStackTrace();
180 }
181 return argTypes;
182 } else if (sqlFlag.equals(SQL_UPDATE)) {
183 int[] tempArgTypes = new int[fields.length];
184 int[] argTypes = new int[fields.length];
185 try {
186 for (int i = 0; tempArgTypes != null && i < tempArgTypes.length; i++) {
187 fields[i].setAccessible(true); // 暴力反射
188 if (fields[i].get(entity).getClass().getName().equals("java.lang.String")) {
189 tempArgTypes[i] = Types.VARCHAR;
190 } else if (fields[i].get(entity).getClass().getName().equals("java.lang.Double")) {
191 tempArgTypes[i] = Types.DECIMAL;
192 } else if (fields[i].get(entity).getClass().getName().equals("java.lang.Integer")) {
193 tempArgTypes[i] = Types.INTEGER;
194 } else if (fields[i].get(entity).getClass().getName().equals("java.util.Date")) {
195 tempArgTypes[i] = Types.DATE;
196 }
197 }
198 System.arraycopy(tempArgTypes, 1, argTypes, 0, tempArgTypes.length - 1); // 数组拷贝
199 argTypes[argTypes.length - 1] = tempArgTypes[0];
200
201 } catch (Exception e) {
202 e.printStackTrace();
203 }
204 return argTypes;
205
206 } else if (sqlFlag.equals(SQL_DELETE)) {
207 int[] argTypes = new int[1]; // 长度是1
208 try {
209 fields[0].setAccessible(true); // 暴力反射
210 if (fields[0].get(entity).getClass().getName().equals("java.lang.String")) {
211 argTypes[0] = Types.VARCHAR;
212 } else if (fields[0].get(entity).getClass().getName().equals("java.lang.Integer")) {
213 argTypes[0] = Types.INTEGER;
214 }
215
216 } catch (Exception e) {
217 e.printStackTrace();
218 }
219 return argTypes;
220 }
221 return null;
222 }
223
224 private List<T> find(int pageNo, int pageSize, Map<String, String> where, LinkedHashMap<String, String> orderby) {
225 // where 与 order by 要写在select * from table 的后面，而不是where rownum<=? )
226 // where rn>=?的后面
227 StringBuffer sql = new StringBuffer(
228 " SELECT * FROM (SELECT t.*,ROWNUM rn FROM (SELECT * FROM " + entityClass.getSimpleName());
229 if (where != null && where.size() > 0) {
230 sql.append(" WHERE "); // 注意不是where
231 for (Map.Entry<String, String> me : where.entrySet()) {
232 String columnName = me.getKey();
233 String columnValue = me.getValue();
234 sql.append(columnName).append(" ").append(columnValue).append(" AND "); // 没有考虑or的情况
235 }
236 int endIndex = sql.lastIndexOf("AND");
237 if (endIndex > 0) {
238 sql = new StringBuffer(sql.substring(0, endIndex));
239 }
240 }
241 if (orderby != null && orderby.size() > 0) {
242 sql.append(" ORDER BY ");
243 for (Map.Entry<String, String> me : orderby.entrySet()) {
244 String columnName = me.getKey();
245 String columnValue = me.getValue();
246 sql.append(columnName).append(" ").append(columnValue).append(",");
247 }
248 sql = sql.deleteCharAt(sql.length() - 1);
249 }
250 sql.append(" ) t WHERE ROWNUM<=? ) WHERE rn>=? ");
251 System.out.println("SQL=" + sql);
252 Object[] args = { pageNo * pageSize, (pageNo - 1) * pageSize + 1 };
253 RowMapper<T> rowMapper = BeanPropertyRowMapper.newInstance(entityClass);
254 return jdbcTemplate.query(sql.toString(), args, rowMapper);
255 }
256
257 private int count(Map<String, String> where) {
258 StringBuffer sql = new StringBuffer(" SELECT COUNT(*) FROM " + entityClass.getSimpleName());
259 if (where != null && where.size() > 0) {
260 sql.append(" WHERE ");
261 for (Map.Entry<String, String> me : where.entrySet()) {
262 String columnName = me.getKey();
263 String columnValue = me.getValue();
264 sql.append(columnName).append(" ").append(columnValue).append(" AND "); // 没有考虑or的情况
265 }
266 int endIndex = sql.lastIndexOf("AND");
267 if (endIndex > 0) {
268 sql = new StringBuffer(sql.substring(0, endIndex));
269 }
270 }
271 System.out.println("SQL=" + sql);
272 return jdbcTemplate.queryForInt(sql.toString());
273 }
274 }
来源：https://www.cnblogs.com/jianguang/p/5884643.html