diff --git a/README.md b/README.md index d1b9a8d..1ca24fe 100644 --- a/README.md +++ b/README.md @@ -2,12 +2,6 @@ 支持连表查询的[mybatis-plus](https://gitee.com/baomidou/mybatis-plus) -## 运行环境 - -* mysql8 -* jdk8 -* mybatis-plus 3.4.2 - ## 使用方法 ### 方法一 @@ -47,6 +41,7 @@ ## MyQuery用法 ### 简单的3表查询 + ```java class test { @Resource @@ -54,55 +49,54 @@ class test { void testJoin() { List list = userMapper.selectJoinList(UserDTO.class, - new MyLambdaQuery() - .selectAll(UserDO.class) - .select("addr.tel", "addr.address") - .select("a.province") - .leftJoin("user_address addr on t.id = addr.user_id") - .rightJoin("area a on addr.area_id = a.id") - .gt(true, UserDO::getId, 1) - .eq(true, UserDO::getSex, "男") - .stringQuery() - .like(true, "addr.tel", "1") - .le(true, "a.province", "1")); + new MyLambdaQuery() + .selectAll(UserDO.class) + .select("addr.tel", "addr.address") + .select("a.province") + .leftJoin("user_address addr on t.id = addr.user_id") + .rightJoin("area a on addr.area_id = a.id") + .gt(true, UserDO::getId, 1) + .eq(true, UserDO::getSex, "男") + .stringQuery() + .like(true, "addr.tel", "1") + .le(true, "a.province", "1")); } } ``` 对应sql - + ```sql -SELECT - t.id, - t.name, - t.sex, - t.head_img, - addr.tel, - addr.address, - a.province -FROM - user t - LEFT JOIN user_address addr on t.id = addr.user_id - RIGHT JOIN area a on addr.area_id = a.id +SELECT t.id, + t.name, + t.sex, + t.head_img, + addr.tel, + addr.address, + a.province +FROM user t + LEFT JOIN user_address addr on t.id = addr.user_id + RIGHT JOIN area a on addr.area_id = a.id WHERE ( - t.id > ? - AND t.sex = ? - AND addr.tel LIKE ? - AND a.province <= ?) + t.id > ? + AND t.sex = ? + AND addr.tel LIKE ? + AND a.province <= ?) ``` 说明: + * UserDTO.class 查询结果类(resultType) * selectAll(UserDO.class) 查询主表全部字段(主表实体类) * select() mp的select策略是覆盖,以最后一次为准,这里的策略是追加,可以一直select -主表字段可以用lambda,会自动添加表别名,主表别名默认是 t ,非主表字段必须带别名查询 + 主表字段可以用lambda,会自动添加表别名,主表别名默认是 t ,非主表字段必须带别名查询 * leftJoin() rightJoin() innerJoin() 传sql片段 格式 (表 + 别名 + 关联条件) * stringQuery() lambda查询转string查询 * lambda() string查询转lambda查询 * sql组装由mp完成,正常使用没有sql注入风险 ### 分页查询 - + ```java class test { @Resource @@ -110,32 +104,29 @@ class test { void testJoin() { IPage page = userMapper.selectJoinPage(new Page<>(1, 10), UserDTO.class, - new MyLambdaQuery() - .selectAll(UserDO.class) - .select("addr.tel", "addr.address") - .select("a.province") - .leftJoin("user_address addr on t.id = addr.user_id") - .rightJoin("area a on addr.area_id = a.id")); + new MyLambdaQuery() + .selectAll(UserDO.class) + .select("addr.tel", "addr.address") + .select("a.province") + .leftJoin("user_address addr on t.id = addr.user_id") + .rightJoin("area a on addr.area_id = a.id")); } } ``` 对应sql - + ```sql -SELECT - t.id, - t.name, - t.sex, - t.head_img, - addr.tel, - addr.address, - a.province -FROM -user t -LEFT JOIN user_address addr on t.id = addr.user_id -RIGHT JOIN area a on addr.area_id = a.id -LIMIT ?,? +SELECT t.id, + t.name, + t.sex, + t.head_img, + addr.tel, + addr.address, + a.province +FROM user t + LEFT JOIN user_address addr on t.id = addr.user_id + RIGHT JOIN area a on addr.area_id = a.id LIMIT ?,? ``` ### 还可以这么操作,但不建议 @@ -147,21 +138,21 @@ class test { void testJoin() { List list = userMapper.selectJoinList(UserDTO.class, - new MyLambdaQuery() - .selectAll(UserDO.class) - .select("addr.tel", "addr.address") - //行列转换 - .select("CASE t.sex WHEN '男' THEN '1' ELSE '0' END AS sex") - //求和函数 - .select("sum(a.province) as province") - //自定义数据集 - .leftJoin("(select * from user_address) addr on t.id = addr.user_id") - .rightJoin("area a on addr.area_id = a.id") - .eq(true, UserDO::getId, 1) - .stringQuery() - .like(true, "addr.tel", "1") - .le(true, "a.province", "1") - .orderByDesc("addr.id")); + new MyLambdaQuery() + .selectAll(UserDO.class) + .select("addr.tel", "addr.address") + //行列转换 + .select("CASE t.sex WHEN '男' THEN '1' ELSE '0' END AS sex") + //求和函数 + .select("sum(a.province) as province") + //自定义数据集 + .leftJoin("(select * from user_address) addr on t.id = addr.user_id") + .rightJoin("area a on addr.area_id = a.id") + .eq(true, UserDO::getId, 1) + .stringQuery() + .like(true, "addr.tel", "1") + .le(true, "a.province", "1") + .orderByDesc("addr.id")); } } ``` @@ -169,23 +160,21 @@ class test { 对应sql ```sql -SELECT - t.id, - t.name, - t.sex, - t.head_img, - addr.tel, - addr.address, - CASE t.sex WHEN '男' THEN '1' ELSE '0' END AS sex, - sum(a.province) as province -FROM -user t -LEFT JOIN (select * from user_address) addr on t.id = addr.user_id -RIGHT JOIN area a on addr.area_id = a.id +SELECT t.id, + t.name, + t.sex, + t.head_img, + addr.tel, + addr.address, + CASE t.sex WHEN '男' THEN '1' ELSE '0' END AS sex, + sum(a.province) as province +FROM user t + LEFT JOIN (select * from user_address) addr on t.id = addr.user_id + RIGHT JOIN area a on addr.area_id = a.id WHERE ( - t.id = ? - AND addr.tel LIKE ? - AND a.province <= ?) + t.id = ? + AND addr.tel LIKE ? + AND a.province <= ?) ORDER BY addr.id DESC ``` @@ -201,12 +190,17 @@ class test { private UserMapper userMapper; void testJoin() { - List list = userMapper.selectJoinList(UserDTO.class, new MyLambdaQueryWrapper() - .selectAll(UserEntity.class) - .leftJoin(UserEntity::getId, UserAddressEntity::getUserId, - r1 -> r1.select(UserAddressEntity::getAddress) - .leftJoin(UserAddressEntity::getAreaId, AreaEntity::getId, - r2 -> r2.select(AreaEntity::getProvince)))); + List list = userMapper.selectJoinList(UserDTO.class, + new MyLambdaQueryWrapper() + .selectAll(UserDO.class) + .select(UserAddressDO::getTel) + .selectAs(UserAddressDO::getAddress, UserDTO::getUserAddress) + .select(AreaDO::getProvince, AreaDO::getCity) + .leftJoin(UserAddressDO.class, UserAddressDO::getUserId, UserDO::getId) + .leftJoin(AreaDO.class, AreaDO::getId, UserAddressDO::getAreaId) + .eq(true, UserDO::getId, 1) + .like(true, UserAddressDO::getTel, "1") + .gt(true, UserDO::getId, 5)); } } ``` @@ -214,98 +208,71 @@ class test { 对应sql ```sql -SELECT t0.name, - t0.sex, - t0.head_img, - t0.id, - t1.address, - t2.province -FROM user t0 - LEFT JOIN user_address t1 ON t0.id = t1.user_id - LEFT JOIN area t2 ON t1.area_id = t2.id -``` - -sql -> 伪代码 - -```java -class test { - void testJoin() { - List list = userMapper.selectJoinList(UserDTO.class, new MyLambdaQueryWrapper() - .selectAll(user表实体类.class)//查询user表全部字段 - .leftJoin(user表on字段, user_address表on字段, - user_address表对象 -> user_address表对象 - .select(user_address表address字段) - .leftJoin(user_address表表的on字段, area表的on字段, - area表对象 -> area表对象.select(area表的province字段)))); - } -} -``` - -#### 字段别名,查询字段别名 head_img as userHeadImg - -```java -class test { - @Resource - private UserMapper userMapper; - - void testJoin() { - List list = userMapper.selectJoinList(UserDTO.class, new MyLambdaQueryWrapper() - .as(UserEntity::getHeadImg, UserDTO::getUserHeadImg) - .leftJoin(UserEntity::getId, UserAddressEntity::getUserId, - right -> right.select(UserAddressEntity::getAddress, UserAddressEntity::getTel))); - } -} -``` - -对应sql - -```sql -SELECT t0.head_img AS userHeadImg, - t1.address, - t1.tel -FROM user t0 - LEFT JOIN user_address t1 ON t0.id = t1.user_id -``` - -#### 左连接 leftJoin(UserEntity::getId,UserAddressEntity::getUserId,right -> right) - -前连个参数是两个表的连接条件: -user left join user_address on user.id = User_address.user_id -第三个参数是右表wrapper对象,可以继续使用,以上方法. - -#### 条件查询 - -```java -class test { - @Resource - private UserMapper userMapper; - - void testJoin() { - List list = userMapper.selectJoinList(UserDTO.class, new MyLambdaQueryWrapper() - .selectAll(UserEntity.class) - .leftJoin(UserEntity::getId, UserAddressEntity::getUserId, - right -> right.select(UserAddressEntity::getAddress, UserAddressEntity::getTel)) - .eq(true, UserEntity::getId, 1) - .like(UserAddressEntity::getTel, "1") - .eq(UserEntity::getId, UserAddressEntity::getUserId)); - } -} -``` - -对应sql - -```sql -SELECT t0.name, - t0.sex, - t0.head_img, - t0.id, - t1.address, - t1.tel -FROM user t0 - LEFT JOIN user_address t1 ON t0.id = t1.user_id +SELECT user.id, + user.name, + user.sex, + user.head_img, + user_address.tel, + user_address.address AS userAddress, + area.province, + area.city +FROM user + LEFT JOIN user_address ON user_address.user_id = user.id + LEFT JOIN area ON area.id = user_address.area_id WHERE ( - t0.id = ? - AND t1.tel LIKE ? - AND t0.id = t1.user_id) + user.id = ? + AND user_address.tel LIKE ? + AND user.id > ?) ``` +说明: + +* UserDTO.class 查询结果返回类(resultType) +* selectAll() 查询指定实体类的全部字段 +* select() 查询指定的字段,支持可变参数,同意个select只能查询相同表的字段 + 故将UserAddressDO和AreaDO分开为连个select +* selectAs() 字段别名查询,用于数据库字段与业务实体类属性名不一致时使用 +* leftJoin() 参数说明 + 第一个参数:参与连表的实体类class + 第二个参数数:连表的ON字段,这个属性必须是第一个参数实体类的属性 + 第三个参数:参与连表的另一个实体类属性 +* 条件查询,可以查询主表以及参与连接的所有表的字段,全部调用mp原生的方法,正常使用没有sql注入风险 + +#### 分页查询 + +```java +class test { + @Resource + private UserMapper userMapper; + + void testJoin() { + IPage iPage = userMapper.selectJoinPage(new Page<>(2, 10), UserDTO.class, + new MyLambdaQueryWrapper() + .selectAll(UserDO.class) + .select(UserAddressDO::getTel) + .selectAs(UserAddressDO::getAddress, UserDTO::getUserAddress) + .select(AreaDO::getProvince, AreaDO::getCity) + .leftJoin(UserAddressDO.class, UserAddressDO::getUserId, UserDO::getId) + .leftJoin(AreaDO.class, AreaDO::getId, UserAddressDO::getAreaId)); + } +} +``` + +对应sql + +```mysql +SELECT user.id, + user.name, + user.sex, + user.head_img, + user_address.tel, + user_address.address AS userAddress, + area.province, + area.city +FROM user + LEFT JOIN user_address ON user_address.user_id = user.id + LEFT JOIN area ON area.id = user_address.area_id +LIMIT ?,? +``` + + diff --git a/src/main/java/com/github/mybatisplus/wrapper/MyAbstractLambdaWrapper.java b/src/main/java/com/github/mybatisplus/wrapper/MyAbstractLambdaWrapper.java index 6d0162d..5020a8e 100644 --- a/src/main/java/com/github/mybatisplus/wrapper/MyAbstractLambdaWrapper.java +++ b/src/main/java/com/github/mybatisplus/wrapper/MyAbstractLambdaWrapper.java @@ -14,6 +14,7 @@ import org.apache.ibatis.reflection.property.PropertyNamer; import java.util.Arrays; import java.util.HashMap; import java.util.Map; +import java.util.Objects; import static java.util.stream.Collectors.joining; @@ -93,8 +94,9 @@ public abstract class MyAbstractLambdaWrapper lambdaClass) { ColumnCache columnCache = columnMap.get(LambdaUtils.formatKey(fieldName)); - Assert.notNull(columnCache, "can not find lambda cache for this property [%s] of entity [%s]", - fieldName, lambdaClass.getName()); + if (Objects.isNull(columnCache)) { + columnCache = new ColumnCache(fieldName, null); + } return columnCache; } diff --git a/src/main/java/com/github/mybatisplus/wrapper/MyLambdaQueryWrapper.java b/src/main/java/com/github/mybatisplus/wrapper/MyLambdaQueryWrapper.java index 2039304..5092634 100644 --- a/src/main/java/com/github/mybatisplus/wrapper/MyLambdaQueryWrapper.java +++ b/src/main/java/com/github/mybatisplus/wrapper/MyLambdaQueryWrapper.java @@ -118,10 +118,20 @@ public class MyLambdaQueryWrapper extends MyAbstractLambdaWrapper MyLambdaQueryWrapper selectAs(SFunction columns, SFunction alias) { Class clazz = MyLambdaUtils.getEntityClass(columns); TableInfo info = TableInfoHelper.getTableInfo(clazz); + Assert.notNull(info, "table can not be find for lambda"); selectColumns.add(new SelectColumn(clazz, info.getTableName(), MyLambdaUtils.getColumn(columns), MyLambdaUtils.getName(alias))); return typedThis; } + public final MyLambdaQueryWrapper selectAll(Class clazz) { + TableInfo info = TableInfoHelper.getTableInfo(clazz); + Assert.notNull(info, "table can not be find -> %s", clazz); + selectColumns.add(new SelectColumn(clazz, info.getTableName(), info.getKeyColumn(), null)); + info.getFieldList().forEach(c -> + selectColumns.add(new SelectColumn(clazz, info.getTableName(), c.getColumn(), null))); + return typedThis; + } + @Override public String getSqlSelect() { if (StringUtils.isBlank(sqlSelect.getStringValue())) {