Field and Parameter Converter

Field Converter

The field converter is used to convert the values queried from the database into the values we need. For example, the value queried from the database is an Integer type number, while we need a Long type value.

Bean Searcher provides 7 field converters:

NumberFieldConvertor

since v3.0.0

Only valid for the BeanSearcher retriever

This converter provides mutual conversion between Integer, int, Long, long, Float, float, Double, double, Short, short, Byte, byte, and BigDecimal (support for BigDecimal starts from v4.0).

Configuration Method

SpringBoot / Grails projects

It is recommended to use the dependency of bean-searcher-boot-starter v3.1.0 +. No configuration is required, and it takes effect automatically. If you need to disable this converter, you need to configure it in application.properties:

properties

bean-searcher.field-convertor.use-number = false

If you use the bean-searcher-boot-starter dependency of version v3.0.x, you need to configure a Bean to enable it:

java

@Bean
public NumberFieldConvertor numberFieldConvertor() {
    return new NumberFieldConvertor();
}

SpringMVC projects

You need to add the following configuration to the xml file for configuring Beans:

xml

<bean id="beanReflector" class="cn.zhxu.bs.implement.DefaultBeanReflector">
    <property name="convertors">
        <list>
            <bean class="cn.zhxu.bs.convertor.NumberFieldConvertor" />
            <!-- Omit the configuration of other field converters -->
        <list>
    </property>
</bean>
<bean id="beanSearcher" class="cn.zhxu.bs.implement.DefaultBeanSearcher">
    <!-- Omit the configuration of other attributes -->
    <property name="beanReflector" ref="beanReflector">
</bean>

Others

java

DefaultBeanReflector beanReflector = new DefaultBeanReflector();
beanReflector.addConvertor(new NumberFieldConvertor());         // Add the converter
// Build the Bean retriever
BeanSearcher beanSearcher = SearcherBuilder.beanSearcher()
        // Omit the configuration of other attributes
        .beanReflector(beanReflector)
        .build();

StrNumFieldConvertor

since v3.0.0

Only valid for the BeanSearcher retriever

Configuration Method

SpringBoot / Grails projects

properties

bean-searcher.field-convertor.use-str-num = false

If you use the bean-searcher-boot-starter dependency of version v3.0.x, you need to configure a Bean to enable it:

java

@Bean
public StrNumFieldConvertor strNumFieldConvertor() {
    return new StrNumFieldConvertor();
}

SpringMVC projects

You need to add the following configuration to the xml file for configuring Beans:

xml

<bean id="beanReflector" class="cn.zhxu.bs.implement.DefaultBeanReflector">
    <property name="convertors">
        <list>
            <bean class="cn.zhxu.bs.convertor.StrNumFieldConvertor" />
            <!-- Omit the configuration of other field converters -->
        <list>
    </property>
</bean>
<bean id="beanSearcher" class="cn.zhxu.bs.implement.DefaultBeanSearcher">
    <!-- Omit the configuration of other attributes -->
    <property name="beanReflector" ref="beanReflector">
</bean>

Others

java

DefaultBeanReflector beanReflector = new DefaultBeanReflector();
beanReflector.addConvertor(new StrNumFieldConvertor());         // Add the converter
// Build the Bean retriever
BeanSearcher beanSearcher = SearcherBuilder.beanSearcher()
        // Omit the configuration of other attributes
        .beanReflector(beanReflector)
        .build();

BoolNumFieldConvertor

since v3.6.1

Only valid for the BeanSearcher retriever

See: https://github.com/troyzhxu/bean-searcher/issues/33

Configuration Method

SpringBoot / Grails projects

It is recommended to use the dependency of bean-searcher-boot-starter v3.6.1 +. No configuration is required, and it takes effect automatically.

If you need to disable this converter, you can configure it in application.properties:

properties

bean-searcher.field-convertor.use-bool-num = false

SpringMVC projects

You need to add the following configuration to the xml file for configuring Beans:

xml

<bean id="beanReflector" class="cn.zhxu.bs.implement.DefaultBeanReflector">
    <property name="convertors">
        <list>
            <bean class="cn.zhxu.bs.convertor.BoolNumFieldConvertor" />
            <!-- Omit the configuration of other field converters -->
        <list>
    </property>
</bean>
<bean id="beanSearcher" class="cn.zhxu.bs.implement.DefaultBeanSearcher">
    <!-- Omit the configuration of other attributes -->
    <property name="beanReflector" ref="beanReflector">
</bean>

Others

java

DefaultBeanReflector beanReflector = new DefaultBeanReflector();
beanReflector.addConvertor(new BoolNumFieldConvertor());           // Add the converter
// Build the Bean retriever
BeanSearcher beanSearcher = SearcherBuilder.beanSearcher()
        // Omit the configuration of other attributes
        .beanReflector(beanReflector)
        .build();

BoolFieldConvertor

since v3.0.0

Only valid for the BeanSearcher retriever

This converter provides type conversion from String | Number to Boolean | boolean. Since v3.1.4, v3.2.3, and v3.3.2, it also supports the conversion from Boolean -> boolean.

For numeric types, it defaults to converting 0 to false and non-0 to true. For String types, it defaults to converting "0" | "OFF" | "FALSE" | "N" | "NO" | "F" (case-insensitive) to false and others to true. Additionally, it provides a method to add which string values should be converted to false, for example:

java

BoolFieldConvertor convertor = new BoolFieldConvertor();
// Add the string value "Nothing" in the database to be converted to false, also case-insensitive
convertor.addFalseValues(new String[] { "Nothing" });

Configuration Method

SpringBoot / Grails projects

properties

bean-searcher.field-convertor.use-bool = false

If you use the bean-searcher-boot-starter dependency of version v3.0.x, you need to configure a Bean to enable it:

java

@Bean
public BoolFieldConvertor boolFieldConvertor() {
    return new BoolFieldConvertor();
}

SpringMVC projects

You need to add the following configuration to the xml file for configuring Beans:

xml

<bean id="beanReflector" class="cn.zhxu.bs.implement.DefaultBeanReflector">
    <property name="convertors">
        <list>
            <bean class="cn.zhxu.bs.convertor.BoolFieldConvertor" />
            <!-- Omit the configuration of other field converters -->
        <list>
    </property>
</bean>
<bean id="beanSearcher" class="cn.zhxu.bs.implement.DefaultBeanSearcher">
    <!-- Omit the configuration of other attributes -->
    <property name="beanReflector" ref="beanReflector">
</bean>

Others

java

DefaultBeanReflector beanReflector = new DefaultBeanReflector();
beanReflector.addConvertor(new BoolFieldConvertor());           // Add the converter
// Build the Bean retriever
BeanSearcher beanSearcher = SearcherBuilder.beanSearcher()
        // Omit the configuration of other attributes
        .beanReflector(beanReflector)
        .build();

DateFieldConvertor

since v3.1.0

Only valid for the BeanSearcher retriever

This converter provides mutual conversion between Date, java.sql.Date, java.sql.Timestamp, LocalDateTime, and LocalDate. It also supports setting the time zone (if not set, the system default time zone is used). For example:

java

DateFieldConvertor convertor = new DateFieldConvertor();
convertor.setZoneId(ZoneId.of("Asia/Shanghai"));

Configuration Method

SpringBoot / Grails projects

It is recommended to use the dependency of bean-searcher-boot-starter v3.1.0 +. No configuration is required, and it takes effect automatically. If you need to modify the time zone, you only need to add it to application.properties:

properties

# This configuration is shared with DateFormatFieldConvertor
bean-searcher.field-convertor.zone-id = Asia/Shanghai

If you need to disable this converter, you need to configure it in application.properties:

properties

bean-searcher.field-convertor.use-date = false

If you use the bean-searcher-boot-starter dependency of version v3.0.x, you need to configure a Bean to enable it:

java

@Bean
public DateFieldConvertor dateFieldConvertor() {
    return new DateFieldConvertor();
}

SpringMVC projects

You need to add the following configuration to the xml file for configuring Beans:

xml

<bean id="beanReflector" class="cn.zhxu.bs.implement.DefaultBeanReflector">
    <property name="convertors">
        <list>
            <bean class="cn.zhxu.bs.convertor.DateFieldConvertor" />
            <!-- Omit the configuration of other field converters -->
        <list>
    </property>
</bean>
<bean id="beanSearcher" class="cn.zhxu.bs.implement.DefaultBeanSearcher">
    <!-- Omit the configuration of other attributes -->
    <property name="beanReflector" ref="beanReflector">
</bean>

Others

java

DefaultBeanReflector beanReflector = new DefaultBeanReflector();
beanReflector.addConvertor(new DateFieldConvertor());           // Add the converter
// Build the Bean retriever
BeanSearcher beanSearcher = SearcherBuilder.beanSearcher()
        // Omit the configuration of other attributes
        .beanReflector(beanReflector)
        .build();

DateFormatFieldConvertor

since v3.1.0

Only valid for the MapSearcher retriever.

This converter can format field values of types Date, java.sql.Date, java.sql.Timestamp, LocalDateTime, LocalDate, LocalTime, java.sql.Time into strings. It provides a very powerful setFormat(String scope, String format) method, which supports setting multiple date formats by scope (the more precise the scope, the higher the priority of using the format). For example:

java

DateFormatFieldConvertor convertor = new DateFormatFieldConvertor();
// Set all date fields in the com.example.sbean package to use the yyyy-MM-dd HH:mm format.
convertor.setFormat("com.example.sbean", "yyyy-MM-dd HH:mm");
// Set date fields of type LocalTime in the com.example.sbean package to use the HH:mm format.
convertor.setFormat("com.example.sbean:LocalTime", "HH:mm");
// Set date fields of type LocalDate in the com.example.sbean package to use the yyyy-MM-dd format.
convertor.setFormat("com.example.sbean:LocalDate", "yyyy-MM-dd");
// Set all date fields in the com.example.sbean.User entity class to use the yyyy-MM-dd HH:mm:ss format.
convertor.setFormat("com.example.sbean.User", "yyyy-MM-dd HH:mm:ss");
// Set fields of type Date in the com.example.sbean.User entity class to use the yyyy-MM-dd HH format.
convertor.setFormat("com.example.sbean.User:Date", "yyyy-MM-dd HH");
// Set the createDate field in the com.example.sbean.User entity class to use the yyyy-MM-dd format.
convertor.setFormat("com.example.sbean.User.createDate", "yyyy-MM-dd");

Note

In the scopes like com.example.sbean:LocalTime and com.example.sbean.User:Date above, the type qualifier after : does not refer to the field type declared in the entity class, but to the data type retrieved by SqlExecutor (i.e., the native field type returned by Jdbc by default).

In addition, it also supports setting the time zone (if not set, the system default time zone will be used). For example:

java

DateFormatFieldConvertor convertor = new DateFormatFieldConvertor();
convertor.setZoneId(ZoneId.of("Asia/Shanghai"));

Enabling the Effect

When a field of date/time type is formatted, the field in the Map object of the retrieval result of the MapSearcher retriever will no longer be of date/time type, but a formatted string. The value type has changed.

Configuration Methods

SpringBoot / Grails Projects

It is recommended to use the bean-searcher-boot-starter dependency of version v3.1.0 +. You only need to configure the relevant date formats in application.properties:

properties

bean-searcher.field-convertor.date-formats[com.example] = yyyy-MM-dd HH:mm      # The content in the square brackets is the scope of the format.
bean-searcher.field-convertor.date-formats[com.example.sbean] = yyyy-MM-dd HH
bean-searcher.field-convertor.date-formats[com.example.sbean\:Date] = yyyy-MM-dd
bean-searcher.field-convertor.date-formats[com.example.sbean.Employee] = yyyy-MM
bean-searcher.field-convertor.date-formats[com.example.sbean.Employee\:Date] = yyyy/MM/dd
bean-searcher.field-convertor.date-formats[com.example.sbean.Employee.entryDate] = yyyy-MM-dd HH:mm
# If you need to modify the time zone, you can add this configuration (this configuration is shared with DateFieldConvertor).
bean-searcher.field-convertor.zone-id = Asia/Shanghai

If you are using application.yml, the configuration is as follows:

yaml

bean-searcher:
  field-convertor:
    date-formats[com.example]: yyyy-MM-dd HH:mm
    date-formats[com.example.sbean]: yyyy-MM-dd HH
    date-formats[com.example.sbean:Date]: yyyy-MM-dd
    date-formats[com.example.sbean.Employee]: yyyy-MM
    date-formats[com.example.sbean.Employee:Date]: yyyy/MM/dd
    date-formats[com.example.sbean.Employee.entryDate]: yyyy-MM-dd HH:mm

If you are using the bean-searcher-boot-starter dependency of version v4.0.0 +, you can also configure it as follows in application.yml:

yaml

bean-searcher:
  field-convertor:
    date-formats:
      com.example: yyyy-MM-dd HH:mm
      com.example.sbean: yyyy-MM-dd HH
      # A hyphen is used instead of a colon in the key.
      com.example.sbean-Date: yyyy-MM-dd
      com.example.sbean.Employee: yyyy-MM
      com.example.sbean.Employee-Date: yyyy/MM/dd
      com.example.sbean.Employee.entryDate: yyyy-MM-dd HH:mm

If you need to disable this converter, you need to configure it in application.properties:

properties

bean-searcher.field-convertor.use-date-format = false

If you are using the bean-searcher-boot-starter dependency of version v3.0.x, you need to configure a Bean to enable it:

java

@Bean
public DateFormatFieldConvertor dateFormatFieldConvertor() {
    DateFormatFieldConvertor convertor = new DateFormatFieldConvertor();
    convertor.setFormat("com.example.sbean", "yyyy-MM-dd HH:mm");
    return convertor;
}

SpringMVC Projects

You need to add the following configuration to the xml file for configuring Beans:

xml

<bean id="mapSearcher" class="cn.zhxu.bs.implement.DefaultMapSearcher">
    <!-- Omit the configuration of other attributes. -->
    <property name="convertors">
        <list>
            <bean class="cn.zhxu.bs.convertor.DateFormatFieldConvertor" />
            <!-- Omit the configuration of other field converters. -->
        <list>
    </property>
</bean>

Using the xml registration method, it is not convenient to call the setFormat(String scope, String format) method during Bean initialization. We can get the Bean of type DateFormatFieldConvertor in the project startup listener and then call its setFormat method to set the format.

Others

java

DateFormatFieldConvertor convertor = new DateFormatFieldConvertor();
convertor.setFormat("com.example.sbean", "yyyy-MM-dd HH:mm");
// Build the MapSearcher retriever.
MapSearcher mapSearcher = SearcherBuilder.mapSearcher()
        // Omit the configuration of other attributes.
        .addFieldConvertor(convertor)
        .build();

EnumFieldConvertor

since v3.2.0

Only valid for the BeanSearcher retriever.

This converter provides type conversion in the direction of String | Integer | int -> Enum (since v3.7.0, it supports converting Integer | int to an enumeration, which is converted according to the enumeration sequence number).

For example, when there is a VARCHAR type field gender (gender) in the database, and the value Male represents male and Female represents female, you can define an enumeration class:

java

public enum Gender {
    Male, Female
}

Then declare it as the type of the corresponding attribute in the entity class:

java

public class User {
    private Gender gender;
    // Omit other...
}

Configuration Methods

SpringBoot / Grails Projects

It is recommended to use the bean-searcher-boot-starter dependency of version v3.2.0 +. No configuration is required, and it will take effect automatically. If you need to disable this converter, you need to configure it in application.properties:

properties

bean-searcher.field-convertor.use-enum = false          # Whether to enable this converter, default is true.
bean-searcher.field-convertor.enum-fail-on-error = true # Whether to report an error when an illegal value cannot be converted, default is true (since v3.7.0).
bean-searcher.field-convertor.enum-ignore-case = false  # Whether to ignore case when converting a string value to an enumeration, default is false (since v3.7.0).

SpringMVC Projects

You need to add the following configuration to the xml file for configuring Beans:

xml

<bean id="beanReflector" class="cn.zhxu.bs.implement.DefaultBeanReflector">
    <property name="convertors">
        <list>
            <bean class="cn.zhxu.bs.convertor.EnumFieldConvertor">
                <property name="failOnError" value="true">  <!-- Whether to report an error when an illegal value cannot be converted (since v3.7.0). -->
                <property name="ignoreCase" value="false">  <!-- Whether to ignore case when converting a string value to an enumeration (since v3.7.0). -->
            </bean>
            <!-- Omit the configuration of other field converters. -->
        <list>
    </property>
</bean>
<bean id="beanSearcher" class="cn.zhxu.bs.implement.DefaultBeanSearcher">
    <!-- Omit the configuration of other attributes. -->
    <property name="beanReflector" ref="beanReflector">
</bean>

Others

java

DefaultBeanReflector beanReflector = new DefaultBeanReflector();
beanReflector.addConvertor(new EnumFieldConvertor());           // Add the converter.
// Build the Bean retriever.
BeanSearcher beanSearcher = SearcherBuilder.beanSearcher()
        // Omit the configuration of other attributes.
        .beanReflector(beanReflector)
        .build();

TimeFieldConvertor

since v3.5.0

Only valid for the BeanSearcher retriever.

This converter supports the mutual conversion between java.sql.Time and LocalTime:

Configuration Methods

SpringBoot / Grails Projects

It is recommended to use the bean-searcher-boot-starter dependency of version v3.5.0 +. No configuration is required, and it will take effect automatically.

If you need to disable this converter, you can configure it in application.properties:

properties

bean-searcher.field-convertor.use-time = false

SpringMVC Projects

You need to add the following configuration to the xml file for configuring Beans:

xml

<bean id="beanReflector" class="cn.zhxu.bs.implement.DefaultBeanReflector">
    <property name="convertors">
        <list>
            <bean class="cn.zhxu.bs.convertor.TimeFieldConvertor" />
            <!-- Omit the configuration of other field converters. -->
        <list>
    </property>
</bean>
<bean id="beanSearcher" class="cn.zhxu.bs.implement.DefaultBeanSearcher">
    <!-- Omit the configuration of other attributes. -->
    <property name="beanReflector" ref="beanReflector">
</bean>

Others

java

DefaultBeanReflector beanReflector = new DefaultBeanReflector();
beanReflector.addConvertor(new TimeFieldConvertor());           // Add the converter.
// Build the Bean retriever.
BeanSearcher beanSearcher = SearcherBuilder.beanSearcher()
        // Omit the configuration of other attributes.
        .beanReflector(beanReflector)
        .build();

JsonFieldConvertor

since v4.0.0

Only valid for the BeanSearcher retriever

This converter supports the conversion from JSON string to POJO and is used in conjunction with the annotation @DbField(type = DbType.JSON) on the field of the SearchBean.

Prerequisites

Since JSON conversion is involved, it is inevitable to use a JSON parsing framework. However, different developers may prefer different JSON frameworks. Therefore, this converter is not bound to a specific JSON framework but allows users to choose their own (currently, there are 5 default frameworks to choose from). You only need to add the following specific dependencies:

Use the Jackson framework

groovy

implementation 'cn.zhxu:xjsonkit-jackson:1.5.1'

Use the Gson framework

groovy

implementation 'cn.zhxu:xjsonkit-gson:1.5.1'

Use the Fastjson framework

groovy

implementation 'cn.zhxu:xjsonkit-fastjson:1.5.1'

Use the Fastjson2 framework

groovy

implementation 'cn.zhxu:xjsonkit-fastjson2:1.5.1'

Use the Snack3 framework

groovy

implementation 'cn.zhxu:xjsonkit-snack3:1.5.1'

If your preferred JSON parsing framework is not included, you can also customize the underlying implementation. Refer to: https://gitee.com/troyzhxu/xjsonkit

Configuration Methods

SpringBoot / Grails projects

It is recommended to use the bean-searcher-boot-starter dependency of v4.0.0+. No configuration is required, and it takes effect automatically.

If you need to disable this converter, you can configure it in application.properties:

properties

bean-searcher.field-convertor.use-json = false

Other configuration items:

properties

# Whether to throw an exception when JSON conversion fails. The default is false, and only warning logs are printed.
bean-searcher.field-convertor.json-fail-on-error = false

SpringMVC projects

You need to add the following configuration to the XML file for configuring beans:

xml

<bean id="beanReflector" class="cn.zhxu.bs.implement.DefaultBeanReflector">
    <property name="convertors">
        <list>
            <bean class="cn.zhxu.bs.convertor.JsonFieldConvertor" />
            <!-- Omit the configuration of other field converters -->
        <list>
    </property>
</bean>
<bean id="beanSearcher" class="cn.zhxu.bs.implement.DefaultBeanSearcher">
    <!-- Omit the configuration of other attributes -->
    <property name="beanReflector" ref="beanReflector">
</bean>

Others

java

DefaultBeanReflector beanReflector = new DefaultBeanReflector();
beanReflector.addConvertor(new JsonFieldConvertor());           // Add the converter
// Build the Bean retriever
BeanSearcher beanSearcher = SearcherBuilder.beanSearcher()
        // Omit the configuration of other attributes
        .beanReflector(beanReflector)
        .build();

Usage Examples

Example 1: Convert a JSON array to a simple object

java

public class User {
    // Database value: {id: 1, name: "Administrator"}
    @DbField(type = DbType.JSON)
    private Role role;
    // Omit other fields...
}

Example 2: Convert a JSON array to a simple List

java

public class User {
    // Database value: ["New student", "Excellent"]
    @DbField(type = DbType.JSON)
    private List<String> tags;
    // Omit other fields...
}

Example 3: Convert a JSON array to a complex List (since v4.2.6)

java

public class User {
    // Database value: [{id: 1, name: "Administrator"},{id: 2, name: "Finance"}]
    @DbField(type = DbType.JSON)
    private List<Role> roles;
    // Omit other fields...
}

ListFieldConvertor

since v4.0.0

Only valid for the BeanSearcher retriever

This converter supports the conversion from string value to List and can be used to handle lightweight one-to-many relationships.

Configuration Methods

SpringBoot / Grails projects

It is recommended to use the bean-searcher-boot-starter dependency of v4.0.0+. No configuration is required, and it takes effect automatically.

If you need to disable this converter, you can configure it in application.properties:

properties

bean-searcher.field-convertor.use-list = false

Other configuration items:

properties

# Separator for each item in the List string. The default is a single English comma.
bean-searcher.field-convertor.list-item-separator = ,

SpringMVC projects

You need to add the following configuration to the XML file for configuring beans:

xml

<bean id="beanReflector" class="cn.zhxu.bs.implement.DefaultBeanReflector">
    <property name="convertors">
        <list>
            <bean class="cn.zhxu.bs.convertor.ListFieldConvertor" />
            <!-- Omit the configuration of other field converters -->
        <list>
    </property>
</bean>
<bean id="beanSearcher" class="cn.zhxu.bs.implement.DefaultBeanSearcher">
    <!-- Omit the configuration of other attributes -->
    <property name="beanReflector" ref="beanReflector">
</bean>

Others

java

DefaultBeanReflector beanReflector = new DefaultBeanReflector();
beanReflector.addConvertor(new ListFieldConvertor());           // Add the converter
// Build the Bean retriever
BeanSearcher beanSearcher = SearcherBuilder.beanSearcher()
        // Omit the configuration of other attributes
        .beanReflector(beanReflector)
        .build();

Usage Examples

Example 1: Convert a single-table field value to a simple List

The user table in the database has a tags field, and its value is a comma-separated string, for example: New student,Excellent. Then the SearchBean can be designed as follows:

java

public class User {
    // You can directly use a List to receive user tags.
    private List<String> tags;
    // Omit other fields...
}

Example 2: Convert a one-to-many joined table to a simple List

The database has a user(id,..) table and its child table user_tag(user_id, tag) for storing user tags. Then the SearchBean can be designed as follows:

java

@SearchBean(tables="user u")
public class User {
    // Use a List to receive user tags.
    @DbField("select group_concat(t.tag) from user_tag t where u.id = t.user_id")
    private List<String> tags;
    // Omit other fields...
}

Example 3: Convert a many-to-many joined table to a simple List

The database has user(id,..), tag(id,name) tables and their association table user_tag(user_id, tag_id) for storing user tags. Then the SearchBean can be designed as follows:

java

@SearchBean(tables="user u")
public class User {
    @DbField("select group_concat(t.id) from tag t, user_tag ut where u.id = ut.user_id and ut.tag_id = t.id")
    private List<Integer> tagIds;  // Collection of tag IDs
    @DbField("select group_concat(t.name) from tag t, user_tag ut where u.id = ut.user_id and ut.tag_id = t.id")
    private List<String> tagNames; // Collection of tag names
    // Omit other fields...
}

Example 4: Convert a many-to-many joined table to a complex List

In Example 3, we got two simple List fields, tagIds and tagNames. Now we combine them into a more complex List. First, define a simple tag class containing id and name fields:

java

public class Tag {
    private int id;
    private String name;
    // Omit Getter and Setter
}

Then the SearchBean is designed as follows:

java

@SearchBean(tables="user u")
public class User {
    // Query all the tag IDs and names and separate them with a colon.
    @DbField("select group_concat(concat(t.id,':',t.name)) from tag t, user_tag ut where u.id = ut.user_id and ut.tag_id = t.id")
    private List<Tag> tags; // Collection of tag objects
    // Omit other fields...
}

Finally, you need to define a list item converter and declare it as a Bean:

java

@Component
public class TagConvertor implements ListFieldConvertor.Convertor<Tag> {
    public Tag convert(String value) {
        String[] vs = value.split(":"); // Split according to the colon
        int tagId = Integer.parseInt(vs[0]);
        String tagName = vs[1];
        return new Tag(tagId, tagName);
    }
}

B2MFieldConvertor

since v3.6.0

Only valid for the MapSearcher retriever

This converter can combine the BFieldConvertor, which is only valid for the BeanSearcher retriever, into an MFieldConvertor, so that it also works for the MapSearcher.

Enable Effect

When not enabled, the value type of the retrieval result of the MapSearcher retriever may not be consistent with the field type declared in the entity class. For example, the field is declared as Long type in the entity class, but the value in the Map object of the retrieval result may be of Integer type (determined by the database column type and the JDBC driver).

After enabling this converter, the value type of the retrieval result of the MapSearcher retriever can be consistent with the field type declared in the entity class.

Note

When the DateFormatFieldConvertor is enabled, and a field of the date/time type is within the formatting range specified by it, then this field will still be formatted as a string, so it will no longer be consistent with the date/time type declared in the entity class.

For performance reasons, this converter is not enabled by default. Users can decide whether to enable it according to their own business needs.

Configuration Methods

SpringBoot / Grails projects

When using the bean-searcher-boot-starter (v3.6.0+) dependency, you can add the following configuration to application.properties to enable it:

properties

bean-searcher.field-convertor.use-b2-m = true

SpringMVC projects

You need to add the following configuration to the XML file for configuring beans:

xml

<bean id="mapSearcher" class="cn.zhxu.bs.implement.DefaultMapSearcher">
    <!-- Omit the configuration of other attributes -->
    <property name="convertors">
        <list>
            <bean class="cn.zhxu.bs.convertor.B2MFieldConvertor">
                <constructor-arg>
                    <list>
                        <bean class="cn.zhxu.bs.convertor.NumberFieldConvertor" />
                        <bean class="cn.zhxu.bs.convertor.StrNumFieldConvertor" />
                        <bean class="cn.zhxu.bs.convertor.BoolNumFieldConvertor" />
                        <bean class="cn.zhxu.bs.convertor.BoolFieldConvertor" />
                        <bean class="cn.zhxu.bs.convertor.DateFieldConvertor" />
                        <bean class="cn.zhxu.bs.convertor.EnumFieldConvertor" />
                        <bean class="cn.zhxu.bs.convertor.TimeFieldConvertor" />
                    <list>
                </constructor-arg>
            </bean>
            <!-- Other field converter configurations are omitted -->
        <list>
    </property>
</bean>

Parameter Converter

To be improved...

Custom Converter

If none of the built-in converters above can meet your requirements, you can implement your special needs through a custom converter. A custom converter only needs to implement the following interfaces:

BFieldConvertor (Implementing this interface supports the BeanSearcher retriever)
MFieldConvertor (Implementing this interface supports the MapSearcher retriever)

Both of these interfaces only require implementing two methods:

boolean supports(FieldMeta meta, Class<?> valueType) - Determine the types of entity class attributes and database values supported by this converter.
Object convert(FieldMeta meta, Object value) - Conversion operation to convert the value to the value of the field type specified by meta.

For specific coding, you can refer to the source code implementations of the built-in converters:

Configuration Methods

SpringBoot / Grails Projects

It is recommended to use the bean-searcher-boot-starter dependency. After customizing the converter, you only need to declare it as a Spring Bean:

java

@Bean
public MyFieldConvertor myFieldConvertor() {
    return new MyFieldConvertor();
}

SpringMVC Projects

You need to add the following configuration to the xml file for configuring Beans:

xml

<bean id="beanReflector" class="cn.zhxu.bs.implement.DefaultBeanReflector">
    <property name="convertors">
        <list>
            <bean class="com.example.MyFieldConvertor" />
            <!-- Omit the configuration of other field converters -->
        <list>
    </property>
</bean>
<bean id="beanSearcher" class="cn.zhxu.bs.implement.DefaultBeanSearcher">
    <!-- Omit the configuration of other attributes -->
    <property name="beanReflector" ref="beanReflector">
</bean>

Others

java

DefaultBeanReflector beanReflector = new DefaultBeanReflector();
beanReflector.addConvertor(new MyFieldConvertor());           // Add the converter
// Build the Bean retriever
BeanSearcher beanSearcher = SearcherBuilder.beanSearcher()
        // Omit the configuration of other attributes
        .beanReflector(beanReflector)
        .build();

Field and Parameter Converter ​

Field Converter ​

NumberFieldConvertor ​

Configuration Method ​

StrNumFieldConvertor ​

Configuration Method ​

BoolNumFieldConvertor ​

Configuration Method ​

BoolFieldConvertor ​

Configuration Method ​

DateFieldConvertor ​

Configuration Method ​

DateFormatFieldConvertor ​

Enabling the Effect ​

Configuration Methods ​

EnumFieldConvertor ​

Configuration Methods ​

TimeFieldConvertor ​

Configuration Methods ​

JsonFieldConvertor ​

Prerequisites ​

Configuration Methods ​

Usage Examples ​

ListFieldConvertor ​

Configuration Methods ​

Usage Examples ​

B2MFieldConvertor ​

Enable Effect ​

Configuration Methods ​

Parameter Converter ​

Custom Converter ​

Configuration Methods ​

Field and Parameter Converter

Field Converter

NumberFieldConvertor

Configuration Method

StrNumFieldConvertor

Configuration Method

BoolNumFieldConvertor

Configuration Method

BoolFieldConvertor

Configuration Method

DateFieldConvertor

Configuration Method

DateFormatFieldConvertor

Enabling the Effect

Configuration Methods

EnumFieldConvertor

Configuration Methods

TimeFieldConvertor

Configuration Methods

JsonFieldConvertor

Prerequisites

Configuration Methods

Usage Examples

ListFieldConvertor

Configuration Methods

Usage Examples

B2MFieldConvertor

Enable Effect

Configuration Methods

Parameter Converter

Custom Converter

Configuration Methods